Production of Benzoic Acid

Table of Contents Cont ents Chapter 1........................................................................ ..... ....................................................... ......... O-Hydroxy benzoic acid and related compounds .............................................. ................................................................................................................ ......... Introduction .......................................................................................................

Chapter 2....................................................................... .... Process selection and description of flow sheet .................................................. ......................................................... ....... Flow Sheet Selection ....................................................................................... ....... ........................................................................................... ....... Flow Sheet Description ....................................................................................

Chapter 3....................................................................... .... Material balance ................................................................................................... .......

Chapter 4....................................................................... .... ner!y "alance .................................................................................................... .......

Chapter 5....................................................................... .... Desi!n of #uipments ........................................................................................... .................................................................................................. ....... Desi!n of $FS%& ............................................................................................. ............................................................................................. ....... .................................................................................................... ....... Flash %an' Desi!n ............................................................................................. ................................................................................. ....... Desi!n of Distillation $olumn .......................................................................... Desi!n of autocla(e ........................................................................................... ....... ............................................................................................... ....... Desi!n of $entrifu!e ........................................................................................ ....................................................................................................... ..... Desi!n of dryer .................................................................................................. Sublimation ....................................................................................................... ............................................................................................................. ......

Chapter 6....................................................................... .. Instrumentation and process control .................................................................. ..... $ontrol scheme of distiallation column .......................................................... .....

Chapter 7....................................................................... .. ................................................................................ ..... "asic principles of Hazop study ...........................................................................

Chapter 8....................................................................... .. Potential Health Eect ………………………………………………121 Chapter ....................................................................... .. $ost stimation ..................................................................................................... .......................................................................................................... .....

!E"E!E#CE$................................................................ ..

2

$hapter )

O-Hydroxy "enzoic *cid and &elated $ompounds

$hapter +o,)

O-HD&O. "+/OI$ "+/O I$ *$ID *+D &0*%D $OMPO1+DS

$hapter )


$hapter ) O-HD&O. "+/OI$ *$ID *+D &0*%D $OMPO1+DS Introduction $ompounds of the !eneral structure

Where the hydroxy is ortho [69-72- 7], meta [99-06.9], or para [9996-7] are commonly known as the monohydroxybenoic acids. !" the three acids, the ortho isomer, salicylic acid, is by "ar the most important. #he main importance o" salicylic acid and its deri$ati$es lies in their antipyretic and anal%esic actions &see 'nal%esics, antipyretics, and anti-in"lammatory a%ents(. )at*ral salicylic acid, which exists mainly as the %l*cosides o" methyl salicylate [++9--6] and salicyl alcohol [90-0+-7], is widely distrib*ted in the roots, bark, lea$es, and "r*its o" $ario*s plants and trees. 's s*ch, their *se as preparations "or ancient remedies is probably as old as herbal therapy. ippocrates recommended the /*ice o" poplar trees as treatment "or eye diseases. alicyl alcohol %lycosides &salicin( [+-12-( occ*r in op*lo*s halsami"era &poplar( and nlix helix &willow( trees. 3ethyl salicylate %l*cosides occ*r in 4et*la &birch( and #o%as &beech( trees. ' more "amiliar so*rce o" methyl salicylate is the lea$es o" 5a*ltheria proc*mbens &winter%reen( &see also hydroxy carboxylic acids(. ree salicylic acid occ*rs in nat*re only in $ery small amo*nts. t has been isolated "rom the roots, plants, blossoms, and "r*it o" pirctea *lmaria, "rom which its ori%inal name, acidi*m spiric*m, was deri$ed. alicylic acid as well as salicy"iltes occ*r in t*lips, hyacinths, and $iolets, and in common "r*its, e%, oran%es, apples, pl*ms, and %rapes, which explains the presence o" salicylic

$hapter )


acid in most wines &+ 8 2(. Physical Properties,

alicylic acid is obtained as white crystals, "ine needles, or "l*""y white crystalline powder. t is stable in air and may discolor %rad*ally in s*nli%ht. #he synthetic "orm is white and odorless. When prepared "rom nat*ral methyl salicylate, it may ha$e a li%htly yellow or pink tint and a "aint, winter%reenlike odor. ydroxybenoic acid crystallies "rom water in the "orm o" white needles and "rom alcohol as platelets or rhombic prisms. pydroxybenoic acid crystallies in the "orm o" monoclinic prisms. ario*s physical properties o" hydroxybenoic acids are listed in #ables +8:. %able )

Physical Properties of Hydroxybenzoic *cids

roperty

al*e &somer( !rtho

3eta

ara

3olec*lar wei%ht

+.+2

+.+2

+.+2

3eltin% point, o;

+19

20<1-20

2+:.1 8 2+1.6

4oilin% point, o;

2++ sw*b

=ensity

+.::,:

+.:7, 22 29

+.:97

>e"racti$e ndex

+.161

lash point &#a% closed-c*p(, o;

+.17

? a &acid dissociation( at 21o;

+.01

.×+0-1

2.6×+0-1

eat o" comb*stion, m@Amolo

.026

.0

.01

eat o" s*blimation, k@Amol o

91.+:

•

,,

#o con$ert @ to cal, di$ide by :.+:.

++6.+

20 29

$hapter )

%able 2


Solubilities of the Hydroxybenzoic *cids in 3ater4 3t 5

#emperat*re, o;

somer

!rtho

3eta

ara

0

0.+2

0.1

0.21

+0

0.+:

0.11

0.10

20

0.20

0.1

0.+

0

0.0

+.1

0.+

:0

0.:2

2.0

+.2

10

0.6:

.0

2.

60

0.90

:.

:.2

70

+.7

7.0

7.0

0

2.2+

++.0

+2.0

Fi!ure ), &eactions of the carboxyl !roup of salicylic acid,

$hapter )


>eactions. #he hydroxybenoic acids ha$e both the hydroxyl and the carboxyl moieties and, as s*ch, participate in chemical reactions characteristic o" each. n addition, they can *nder%o electrophilic rin% s*bstit*tion. >eactions characteristic o" the carboxyl %ro*p incl*de decarboxylationB red*ction to alcoholsB and the "ormation o" salts, acyl halides, amides, and esters. >eactions characteristic o" the phenolic hydroxyl %ro*p incl*de the "ormation o" salts, esters, and ethers. >eactions in$ol$in% "orm sodi*m salicylate. owe$er, i" salicylic acid dissol$es in the presence o" alkali metals or ca*stic alkalies, e.%., excess sodi*m hydroxide, the disodi*m salt "orms. alicylic acid can be con$erted to salicyloyl chloride by reaction with thionyl chloride in boilin% benene. owe$er, the "ormation o" acyl halides can be complicated by the presence o" the phenolic hydroxyl. or example, the reaction with phosphor*s to arid pentachlorides is not restricted to the "ormation o" the acid chloride. *rther interaction o" the phosphor*s halide and the phenolic hydroxyl res*lts in the "ormation o" the phosphoric or ph osphoro*s esters. #he "ormation o" amides can be accomplished by the dehydration o" the ammoni*m salt o" salicylic acid. #he more common method "or amides is the reaction o" the ester, acylhalide, or anhydride with an amine or ammonia. Cach step is "ast and essentially irre$ersible. Csteri"ication is "reD*ently carried o*t by direct reaction o" the carboxylic acid with an alcohol in the presence o" a small amo*nt o" mineral acid, *s*ally concentrated s*l"*ric or hydrochloric acid. #he ester o" commercial importance is methyl salicylate. =irect esteri"ication has the ad$anta%e o" bein% a sin%le-step synthesisB its disad$anta%e is the re$ersibility o" the reaction. #he eD*ilibri*m can be shi"ted to the ri%ht i" either raw material is *sed in lar%e excess, or by selecti$e remo$al o" one o" the prod*cts. !ne less "reD*ently employed techniD*e is the trans"ormation o" the acid to the acid chloride "ollowed by alcoholysisB each step is essentially irre$ersible. 'nother method is the reaction o" the alkali salt, e%, sodi*m salicylate, with an alkyl or an aryl alkyl halide.

$hapter )


ydroxyl. #he hydroxyl %ro*p is alkylated readily by the sodi*m salt and an alkyl halide &Williamson ether synthesis( &see i%. 2(. )ormally, only !alkylation is ob rin% s*bstit*tion incl*des nitration, s*l"onation, halo%enation, alkylation, and acylation. #he "ollowin% reactions are ill*strated only with salicylic

acidB

howe$er,

these

reactions

are

characteristic

o" all

the

bydroxybenoic acids. %able 6 Solubilities of the Hydroxybenzoic *cids in +on a#ueous Sol(ents4 3t 5

ol$ent

somer !rtho

3eta

ara

'cetone at 2o;

96

27

21

4enene at 21 o;

0.771

0.0+0

0.001

+-b*tanol

2-.- ,-c ;

20.7 ,6.1c ;

+9.1 22.1c ;

Cthanol &99 wt E(

:0.6 :+c ;

,.9.6 61c ;

,-.71 67c ;

n-heptane

2.09 92.2c ;

2.0+97c ;

+.1+97c ;

3ethanol at +1 o;

9.7

:0.

6.22

;arbon tetrachloride at 21 o;

0.262

;hloro"orm &satd in  2!( at 21 +.: o ; Cthanol &abs( at 2+ o;

:.7

-propanol at 2+ o; 27.6 %able 7 Saturated 8apor Pressure 9p: of o- and p-Hydroxybenzoic *cids %emperature4 o $

o-Hydroxybenzoic acid p4 Pab

91

0.9

+00

:.7

+01

70.+

++0

+0:

++1

+1

+20

220

p-Hydroxybenzoic acid p4 Pab

$hapter )


+21

22

+0

.0 :.19

+1

6:9

6.9:

+:0

+0.6

+:1

+6.+

+10

2.9

+11

:.6

+19

:7. 4. #o con$ert a to mm %, di$ide by +..

Salicylic *cid &eactions; ;arboxyl. #ypical decarboxylation by simple heatin% o" a

"ree acid occ*rs with only a "ew types o" acids. owe$er, decarboxylation o" salicylic acid takes place readily beca*se o" the presence o" the hydroxyl %ro*p, which is electron donatin% &see i%. +(. Fpon slow heatin%, salicylic acid decomposes to phenol and carbon dioxideB when heated rapidly, it s*blimes. 5enerally, the carboxyl %ro*p is not readily red*ced.
$hapter )


Fi!ure 2, &eactions of the hydroxyl !roup of salicylic acid,

Csters o" the phenolic hydroxyl are obtained easily by the chotten4a*mann reaction. #he reaction in many cases in$ol$es an acid chloride as the acylatin% a%ent. owe$er, acylation can also be achie$ed by reaction with an acid anhydride. #he sin%le most important commercial reaction o" this type is the acetylation o" salicylic acid with acetic anhydride to yield acetylsalicylic acid [107-2] &aspirin(. >in% *bstit*tion. n the introd*ction o" a third %ro*p into a disnbstit*ted benene, the position the %ro*p takes depends on the %ro*ps present &see i%. (. n the case o" salicylic acid the h$droxyl directs ortho and pan and the carboxyl directs meta s*bstit*tion. t is %enerally accepted that i" both an ortho-para and a meta director are competin% "or the orientation o" a third %ro*p, the ortho-para director pre$ails since, *nlike the meta director, it acti$ates the rin%. peci"ically, the hydroxyl %ro*p is electron-donatin% which, on the basis o" resonance considerations, increases the

$hapter )


Fi!ure 6 &in!-substitution reactions of salicylic acid, . < halo!en,

Clectron density in the  and 1 positions. #he electron-withdrawal nat*re o" the car-boxyl %ro*p decreases the electron density aro*nd the : and ; positions, which "*rther enhances the electron density o" the  and 1 positions. 's a r*le, direct s*bstit*tion occ*rs more easily in the less sterically hindered 1 position, b*t most o"ten small amo*nts o" the  s*bstit*ted and ,1-dis*bstit*ted prod*ct also "orm. i%h yields o" the -s*bstit*ted salicylic acid *s*ally can only be prepared indirectly. =irect halo%enation o" salicylic acid is %enerally carried o*t in %lacial acetic acid. 's expected, the main prod*ct is the 1-halo-salicylic acid with small D*antities o" the -halo- and , 1-dihalosalicylic acids. >eaction with cold nitric acid res*lts primarily in the "ormation o" 1nitrosalicylic acid [96-97-9]. owe$er, reaction with "*min% nitric acid res*lts in decarboxylation as well as the "ormation o" 2, :, ;-trinitrophenol [-9-+]

$hapter )


&picric acid(. *l"onation with chloros*l"onic acid at +6!o; yields 1-s*l"osalicylic acid [16107-0-]. 't hi%her temperat*res &+00 ;( and with an excess o" chloros*l"onic acid, ,1-dis*l"osalicylic acid "orms. *l"onation with liD*id s*l"*r trioxide in tetrachloroethylene leads to a nearly D*antitati$e yield o" 1s*l"osalicylic acid &1(. 4eca*se salicylic acid contains the deacti$atin% meta-directin% carboxyl %ro*p, riedel-;ra"ts reactions &D$( are %enerally inhibited. #his e""ect is somewhat o""set by the presence o" the acti$atin% hydroxyl %ro*p. alicylic acid also reacts with isob*tyl or t-b*tyl alcohol in 0 wt E s*l"*ric acid at 71 0; to yield 1-t-b*tylsalicylic acid [+609:-+-]. n the case o" isob*tyl alcohol, the intermediate carboni*m ion rearran%es to &;(;H. Miscellaneous, #he >eimer-#iemann reaction o" salicylic acid with

chloro"orm and alkali res*lts in the - and 1-"ormyl deri$ati$es.

" the reaction is carried o*t with carbon tetrachloride, the correspondin% dicarboxylic acids "orm.

'lkylation in$ol$in% "ormaldehyde in the presence o" hydro%en

$hapter )


chloride is known as chloromethylation. #he rea%ent may be a mixt*re o" "ormalin and hydrochloric acid, para"ormaldehyde and hydrochloric acid, a chloromethyl ether, or a "ormal. Iinc chloride is commonly employed as a catalyst, altho*%h many others can be *sed. ;hloromethylation o" salicylic acid yields primarily the 1-J*bstit*ted prod*ct. #he reaction o" salicylic acid with "ormaldehyde with catalytic amo*nts o" acid res*lts in the condensation prod*ct methylene-1, 1K-disalicylic acid [+2221-].

alicylic acid, *pon reaction with amyl alcohol and sodi*m, red*ces to a rin%-opened aliphatic dicarboxylic acid, ie, pimelic acid. #he reaction proceeds thro*%h the intermediate cyclohexanone-2-carboxylic acid.

=*rin% certain s*bstit*tion reactions, the carboxyl %ro*p is o"ten replaced by the enterin% %ro*p. '* example is "*min% nitric acid, which res*lts in the "ormation o" trinitrophenol. 'nother is the bromination o" salicylic acid in aD*eo*s sol*tion to yield the tribromophenol deri$ati$e.

$hapter )


alicylic acid co*ples with diaoni*m salts in the expected manner. With diaotied aniline, i.e, benenediaoni*m chloride, the primary prod*ct is 1 phenylaosalicylic acid [+: 7-1-].

#he close proximity o" the carboxyl and the hydroxyl %ro*ps can be *sed "or beterocyclic synthesis, as in the preparation o" hydroxyxanthones &6(.

1SS 'pproximately 60E o" the salicylic acid prod*ced in the Fnited tates is cons*med in the man*"act*re o" aspirinL this statistic has remained relati$ely constant "or at least the last ten years. 'pproximately +0E o" the salicylic acid prod*ced is cons*med in $ario*s applications, e%, "o*ndry and phenolic resins, r*bber retarders, dyest*""s, and other miscellaneo*s *ses. #he remainin% 0E is *sed in the man*"act*re o" its salts and esters "or a $ariety o" applications. #here are many "o*ndry-resin systems in *se. alicylic acid is a small component only in the hell process. t is *sed as a cross-linkin% a%ent in the phenolM"ornrnldehyde resin *sed as a sand core and mold binder and imparts hi%her tensile stren%th. 3ore recent de$elopments ha$e demonstrated that hi%her concentrations o" salicylic acid than pre$io*sly *sed "*rther impro$e cold and hot

$hapter )


tensile stren%th and red*ce c*re and machine processin% time &+(. #he contin*in% interest in ener%y and en$ironmental considerations has led to the low ener%y processes, which typically do not *se salicylic acid. #heir %rowth has been somewhat limited beca*se o" the lar%e capital expendit*res reD*iredB howe$er, the economics is expected to shi"t as the cost o" ener%y increases. #here"ore, a ero or small ne%ati$e %rowth "or salicylic acid is predicted in "o*ndry-resin applications. alicylic acid has also been *sed in other phenolic resin applications, ie, binders "or %rindin% wheels, "iber %lass, and brake linin%s &D$( &see henolic resins(.

$hapter )


$hapter +o, 2

Process Selection and Description Of Flow Sheet

$hapter )


$hapter 2 Process Selection and Description of Flow Sheet FI&S% S+%HSIS alicylic acid was "irst prepared by >.iria by the "*sion o" salicyaldehide with the potassi*m hydroxide. n +19, a synthesis method o" preparin% salicylic acid was disco$ered by treatin% the phenol with carbon dioxide in presence o" metallic sodi*m. owe$er the only commercial method o" man*"act*rin% salicylic acid *ntil +7: was the sponi"ication o" the methyl salicylate obtained "rom the lea$es o" the winter %reen or 4ark o" the birch.

=O0" P&O$SS #he "irst technically s*itable process was introd*ced in +7: by ?olb. t in$ol$es the reaction o" the dry sodi*m phenolate with carbon dioxide *nder press*re and hi%h temperat*re &+0-200( 0;. #he drawback o" the process was that the yield was not more than 10E and the separation o" byprod*cts which were in lar%e D*antity was di""ic*lt. alicylic acid is man*"act*red by the reaction o" phenol with ca*stic soda and the s*bseD*ent treatment o" the sodi*m phenolate "ormed with carbon dioxide and acidi"yin% the res*ltant prod*ct with the s*l"*ric acid .henol and ca*stic soda are char%ed in eD*omolar proportions to a mixer. #he res*ltin% sol*tion is heated to a temperat*re o" +00; and "*rther e$aporated to dryness in a stirred a*tocla$e or a heated ball mill. =ry carbon dioxide %as is absorbed and the cr*de prod*ct "rom the a*tocla$e is dissol$ed in the eD*al amo*nt o" water and "iltered. #he "iltrate is precipitated and dried.#o obtain p*re prod*ct, the cr*de sodi*m salicylate sol*tion decoloried with the acti$ated carbon containin% the inc d*st and "iltered. #he clari"ied "iltrate is acidi"ied with the excess o" s*l"*ric acid to precipitate the salicylic acid which is centri"*%ed and dried to %i$e the hi%h %rade salicylic acid.

$hapter )


S$HMI%% chmitt introd*ced the new lower temperat*re ran%es "rom +20+:00; which si%ni"icantly increased the yield o" the process. #he reaction o" the carbon dioxide on the phenol "orms an intermediate phenyl carbonate which rearran%es itsel" to %i$e o-sodi*m salicylate. #he ?olb-chmitt synthesis method is still the only ind*strial process in *se in di""erent modi"ications.

More4 et al 3ore introd*ced a new step process "or the carbonation o" dry sodi*m phenolate. #he reaction is carried o*t in a stirred reactor. ;arbon dioxide is passed at a temperat*re o" +00; *ntil 21E o" the stiochiometeric amo*nt o" the carbon dioxide is absorbed. n step ++ the temperat*re o" the raised to 2+00;and the remainin% carbon dioxide is introd*ced into the reactor "or 1 hr. the yield o" the process was 0 to 2E and "or time d*ration the yield was 76E.

Stopp4et al #he carbonation o" the sodi*m salicylate is carried o* t in a "l*idied bed reactor at +:00; and press*re o" 6bar *ntil hal" o" the phenolate is con$erted to salicylate. #he res*ltin% reaction mixt*re can be "*rther carbona ted in a s*bseD*ent sta%e at a temperat*re o" 2+00;and a press*re o" +0 bars. #he s*bseD*ent sta%e may be "l*idied bed reactor or stirred $essel. #he yield was 1E.

"ar'ley et al #he sodi*m phenolate was cooled to 90 0;. #he carbon dioxide was passed into the a*tocla$eB the temperat*re was maintained at +20 0; *ntil the carbon dioxide adsorption was come to an end. #he temperat*re was raised to ind*ced rearran%ement o" the intermediate prod*ct. #he temperat*re was kept +60-+700;*nder a carbon dioxide press*re 1 bar.

>enson4 et at 'n impro$ed method "or the prod*ction o" salicylic acid "rom phenol with hi%h de%ree o" con$ersion and with a si%ni"icant red*ction in the by prod*cts was modi"ied by @enson and his collea%*es. #he process comprises o" reaction o"

$hapter )


sodi*m phenolate with the carbon dioxide indirect sin%le step at a temperat*re abo$e +610;.n the ?olb carboxylation, the reaction between sodi*m phenolate with carbon dioxide co*ld ad$anta%eo*sly takes place in sin%le step well the temperat*re at which sodi*m phenyl carbonate is ordinarily con$erted to sodi*m salicylate. 3ore partic*larly instead o" introd*cin% carbon dioxide below +10 0; to prod*ce sodi*m phenyl carbonate which is then in second step is con$erted to sodi*m salicylate bein% held abo$e +610;.

Our contributions #he reaction o" sodi*m phenolate and carbon dioxide is slowest reaction in whole plant so e$ery scientist "oc*sed his attention "or "indin% the set o" thermodynamics properties that wo*ld %i$e maxim*m con$ersion and minim*m byprod*ct as well as cost "actor wo*ld remain *nder considerations alon% with the sa"e operation.  was personally interested in "indin% s*ch data to impro$e the per"ormance o" the plant *sed "or man*"act*rin% o" salicylic acid. #he a*tocla$e present in o*r department was D*ite *ns*itable "or the reaction o" carbon dioxide with sodi*m phenolate at di""erent temperat*re and press*re. 4*t "ort*nately the circ*mstances "or carryin% the experiments in determination the kinetic data  was %i$en opport*nity in the chemistry department lab.  per"ormed n*mber o" experiment at di""erent temperat*re and di""erent speed o" a%itation in simple conical "lask. '"ter the res*lt o" experiment  decided batch reaction was not economical. o  made chan%es in the "low dia%ram a$ailable in literat*re.

$hapter )


$hapter )


F0O3 SH% DS$&IP%IO+ Preparation of Sodium Phenolate henol is approximately 1:E is reacted with 10Eca*stic soda in a ;#>. #he reaction temperat*re is 91-99 0;. #he reaction is exothermicB heat e$ol$ed "rom the reaction is *tilied raisin% the temperat*re o" the prod*ct to 990;. li%htly excess amo*nt o" phenol is "ed into the reactor instead o" ca*stic soda beca*se o" material o" constr*ction is %reatly in"l*enced by the stron% alkali. #he reaction temperat*re is so hi%h that l*mp "ormation o" sodi*m phenolate is o*t o" D*estion. Preparation of Sodium salicylate #he prod*ct o" the "irst reactor is "ed into the "lash tank where separation o" water is carries o*t and then "or any batch $al$e is opened and a*tocla$e is char%ed and $al$e o" the carbon dioxide is opened at the press*re o" bars "or the time o" 1-6hrs. #he reaction temperat*re is raised to abo*t +210;. 'lmost 70E con$ersion is achie$edB carbon dioxide released is recycled back and then *tilied. )ow 600?% o" phenol is added so that some sort o" aeotrope is "ormed and when steam is pro$ided, this mixt*re is $aporied lea$in% the thick sl*rry o" sodi*m salicylate. #he e$aporated material is condensed and sent into the contin*o*s distillation col*mn where separation o" phenol and sodi*m phenate is carried o*t.

*cidification tan' #he prod*ct o" the a*tocla$e is thick sl*rry and it is dil*ted with the water in the dil*tion tank. #he sol*tion, so obtained is char%ed into the acidi"ication tank where :0E s*l"*ric acid is reacted that comes "rom the stora%e tank o" s*l"*ric acid. 'lmost two hr alon% with a%itation %i$es +00 app. ;on$ersion. n the acidi"ication tank solid salicylic acid as well as sodi*m s*l"ate is "ormed

$hapter )


Purification from water 9remo(al of water: >emo$al o" water is carried in two stepsL in "irst step centri"*%e remo$es the lar%e amo*nt o" water i.e. "rom 66 to +6 Ewater content. #he waste water is sent to the waste water treatment plant. #he solid prod*ct that contains salicylic acid and sodi*m s*l"ate is sent to the dryer where app. 'll water content is remo$ed.

Sublimation and crystallization #he solid prod*ct is char%ed into the s*blimation tank where steam is *sed as heatin% medi*m and $ac**m is created with the help o" $ac**m p*mp. 't red*ced press*re the s*blimation o" salicylic acid is carried o*t at 760;. #he $apors comin% "rom the s*blimation tank are in/ected into crystallier where condensation o" $apors takes place res*ltin% more than 99E p*re prod*ct.

$hapter )


$hapter +o, 6

Material "alance

$hapter )


$hapter 6 Material "alance Reactor-1 output

input component NaOH H2O phenol Na-h total

(Kgmol) 10.65625 66.48056 11.7216 0 88.8584

Kg 426.25 1196.65 1101.83 0 2724.73

%Wt 15.64375 43.91811 40.43814 0 100

Kgmol 0.156 76.98056 1.22 10.5 88.85656

Kg 6.24 1385.65 114.68 1218 2724.57

%Wt 0.22902697 50.8575665 4.20910456 44.704302 100

Kg 6.24 35 101.16 1218 1360.4

%Wt 0.45868862 2.57277271 7.43604822 89.5324904 100

FLASH TANK

input component NaOH H2O henol Na-h

(Kgmol) 0.156 76.98056 1.22 10.5 88.85656

output Kg 6.24 1385.65 114.68 1218 2724.57

%Wt 0.229027 50.85757 4.209105 44.7043 100

Kgmol 0.156 1.944444 1.07617 10.5 13.67661

side stream !ate"-o#t total phenol

1350.65 2711.05 13.52

$O2

side stream 231

Autoca!e reactor-2 Addition o" #$2 and reaction

input component NaOH H2O henol Na-h $O2 Na-al

(Kgmol) 0.156 1.944444 1.07617 10.5 12.6

output Kg %Wt Kgmol Kg %Wt 6.24 0.325951 0.156 6.24 0.36897969 35 1.828249 1.9444 35 2.06959761 101.16 5.284162 1.07617 101.16 5.98172841 1218 63.62307 3.15 365.4 21.6065991 554 28.93857 0 0 0 0 7.35 1183.35 69.9730952 1914.4 100 1691.15 100 Addition o" p%eno and separation o" a&eotrope


(Kgmol) 0.156 1.9444 6.395319 3.15 7.35

output Kg 6.24 35 601.16 365.4 0 1183.35

%Wt 0.284782 1.597335 27.43582 16.67617 0 54.00589

Kgmol 0.156 1.9444 0.01234 0.012069 0 7.35

Kg 6.24 35 1.16 1.4 0 1183.35

%Wt 0.50849529 2.85213707 0.09452797 0.11408548 phenol 0 Na-h 96.4307542

side stream 600 364

$hapter )


2191.15

100

1227.15

100

Kg 6.24 2489.3 1.16 1.4 0 1183.35 3681.45

%Wt 0.16949843 67.617379 0.03150932 0.03802849 0 !ate" 32.1435847 100

Kg 0 3033.55 1.16 1.4 1014.3 0 541.85

%Wt 0 66.0226652 0.02524642 0.03046982 22.0753867 0 11.7929097 0 0.05332219 100

'iution tan(


(Kgmol) 0.156 1.9444 0.01234 0.012069 0 7.35

output Kg 6.24 35 1.16 1.4 0 1183.35 1227.15

%Wt 0.508495 2.852137 0.094528 0.114085 0 96.43075 100

Kgmol 0.156 138.2944 0.01234 0.012069 0 7.35

side input 2454.3

Acidi"ication tan(

input component NaOH H2O henol Na-h &al'cl'c ac'* Na-al Na2O4

(Kgmol) 0.156 138.2944 0.01234 0.012069 0 7.35 0 side input

&#l+#"'c ac'* !ate"

output Kg 6.24 2489.3 1.16 1.4 0 1183.35 0

%Wt 0.169498 67.61738 0.031509 0.038028 0 32.14358 0

362.6 543.9 4587.95 #entri"u)e

2.45 4594.71

input component NaOH H2O henol Na-h &al'cl'c ac'* Na-al Na2O4 &#l+#"'c ac'*

Kgmol 0 168.5306 0.01234 0.012069 7.35 0 3.815845

(Kgmol) 0 168.5306 0.01234 0.012069 7.35 0 3.815845

output Kg 0 3033.55 1.16 1.4 1014.3 0 541.85 2.45 4594.71

%Wt 0 66.02267 0.025246 0.03047 22.07539 0 11.79291 0.053322 100

Kgmol 0 16.46667 0.001702 0.003448 7.35 0 3.799296 0.0125

side stream Kgmol Kg 0 0 152.0639 2737.15 0.01063 1 0.008621 1 0 0 0 0 2.35,142 2.35 0.0125 1.225 2742.725

Kg 0 296.4 0.16 0.4 1014.3 0 539.5 1.225 1851.985

%Wt 0 16.0044493 0.00863938 0.02159845 54.7682622 0 29.1309055 0.06614524 100

Kg 0 2.96

side stream %Wt Kgmol Kg 0 0 0 0.19008965 16.30222 293.44

%Wt 0 99.79673 0.03646 0.03646 0 0 0.085681 0.044664 100

'r*in) unit

input component NaOH H2O

(Kgmol) 0 16.46667

output Kg 0 296.4

%Wt 0 16.00445

Kgmol 0 0.164444

%Wt 0 99.53023

$hapter )

henol Na-h &al'cl'c ac'* Na-al Na2O4 &#l+#"'c ac'*

0.001702 0.003448 7.35 0 3.8 0.0125


0.16 0.4 1014.3 0 539.5 1.225 1851.985

0.008639 0.021598 54.76826 0 29.13091 0.066145 100

0 0.003448 7.35 0 3.8 0

0 0.4 1014.3 0 539.5 0 1557.16

0 0.001702 0.02568779 0 65.137815 0 0 0 34.6464076 0 0 0.0125 100

0.16 0 0 0 0 1.225 294.825

0.054269 0 0 0 0 0.415501 100

Su+imation unit and #r*stai&ation

input component NaOH H2O henol Na-h &al'cl'c ac'* Na-al Na2O4 &#l+#"'c ac'*

(Kgmol) 0 0.164444 0 0.003448 7.35 0 3.8 0

output Kg 0 2.96 0 0.4 1014.3 0 539.5 0 1557.16

%Wt 0 0.19009 0 0.025688 65.13781 0 34.64641 0 100

Kgmol 0 0.069444 0 0 7.333333 0 0 0

Kg 0 1.25 0 0 1012 0 0 0 1013.25

side stream %Wt Kgmol Kg 0 0 0 0.12336541 0.095 1.71 0 0 0 0.4 99.8766346 2.3 0 0 0 539.5 0 0 100 543.91

%Wt 0 0.345829 0 0.080896 0.46515 0 109.1081 0 110

$hapter )


$hapter +o,7

+&? "*0*+$

$hapter )


$hapter 7 +&? "*0*+$ FO& %H P&O>

%$&*$%O& ) +&? "*0*+ ; )aoO+0.66k%mol H Water O

+00E ;on$ersion at 91 ;

)a-phenO Water O

henolO++.72k%mol 2! O

N > O P "p - P  "r

N >

O Q +0.616R&-26.6( H +0.616&-21.:(S8Q+0.616&-+61( H +0.616&-:26.99(S O 19.2:7 ?@

#!#'< C'# >TF>C= O m; p d# H N >

N

O &+.22R220.1?@A?%mol.? R &76.9R71R1(water H&+0.1R2:.+7R1( 0.+16R7.62R1 H 19.2:7 ?@ O :099 ?@

1( phenolH H

$hapter )


C)C>5U 4'<');C 4'<' );C ! 'F#!;<' 'F#!;<'CL

;!2O+2.6k%mol 0 ;

#O+02 ;

70 E con$ersion

)a!O0.+16k%m Water O +.9: k%m henolO +.07k%m )a-phenO+0.1 AA

#O+21; )aoO0.+16k%mol WaterO+.9:: AA henolO+.07 AA )a-phenO.+1 AA )a-sal. O 7.1 AA

;!2O1.21 k% mol #O+21 ;

+ # #C L C'>'#!) C'>'#!) ! !  W' W'#C> #!#'< C'# >TF>C= O sensible heat H latent heat O Q 0.+1 0.+16R 6R7 7R7 R7S S )a! H Q 76.9 76.9R R71 71R7 R7S Swater HQ+.22R29R+7S phenolHQ +0.1R2:R7S )a-ph H Q+10.61R211+.6Swater H Q +.12A9: R:1700 ?@A?%molS phenol O 1++0.1 ?@

2nd #CL '==#!) ! ;! 2 ')= >C';#!) C'# ! >C';#!) O N > OP OP  H P> <'# <'#C)# C'# C'# >CTF>C= O &+2.6R .61R91(;!2H 0.+16R7R7( )ao H &+.9::R71R+(2! H &+.07++7R220R+( phenol H&+0.1R2:.+7R+( )a-ph O 99+0 ?@

#!#'< C'# >TF>C= O  O  l H N> O O 0

$hapter )


l O N> l O Pn"p - Pn"r, Pn"r H H l O Pn"p 7.1&-9.1+R +000( H7.1&-:1R+000( H7.1&-:1R+000( O -7.1R V V

O 19.1++ ?@A%mol

V

O 90 90:.7: ?@A%mol

1E loss so,

rd stepL

addition o" phenol and separation o" aeotrope 3'#)5 #C ;!#C)#

C)C>5U 4'<');C ! =<
eat balanceL +7R71R&#-21(

O Q& 0.+16R7R&+21-#(( )a! H&+.9::R71R&+21-#((2! H&0.0+2:R220R&+21-#(( phenolH&7.1R217.76R&+21-#((sod.sal H&0.0+2069R2:R&+21-#(( )a-phen

#here"ore, +12+H+22.71H9.1H26+7H661.96H21671O#Q+02718 +2.+6H+:1.H2.7+:H+9:. 16H2.9(S #O 62.97 ;

';=;'#!) #')? > O

n"p - n"r

Q-96909 Q-96909H&9 H&970R 70R::( ::(SR+ SR+000 000

O Q.++ Q.++1R& 1R&-+ -+:.1 :.1R+00 R+000(? 0(?@H @H 7.1R&-19.1R+000(SQ&-90:R7.1(H&-++R.69(H0.+16R&-:26(SR+000

$hapter )


> O 9:0 ?@ #his m*ch amo*nt o" heat is contained co ntained a"ter the reaction in the system. )ow reaction temp. is 20 ;

eat balanceL eat inp*t O eat o*t p*t Q.69R+7.777R1S2!: HQ 0.2 0.22R 2R71 71R1 R1S Swater H Q 0.+16R 16R7R&6 R&6-20(S )a! HQ+.29::R71R&6-20(Swater H H Q 0.0+2:R220R:S phen H Q0.0+20R69R2:.+7R&620(S )a-phen H Q7.1R217.76R:S )a-sal O 1:2097.71 ?@ #his m*ch amo*nt is contained in the system be"ore reaction occ*rs. )ow the total amo*nt o" heat that m*st be re/ected to keep the system at 20; O 1:2097.71 H 9:0 O 61171.7

$hapter )


$hapter +o, @ Desi!n of #uipments

$hapter )


$hapter @ Desi!n of #uipments &*$%O& DSI?+ &eactor selection I selected the ;#> >eactor selection criteria

+- ;on$ersion 2- selecti$ity - prod*cti$ity :- sa"ety 1- economics 6- a$ailability 7- "lexibility - compatibility with processin% 9- ener%y *tiliation +0- "easibility ++- in$estment operatin% cost +2- heat exchan%e and mixin%

>eaction rate

ol*m e "low rate

ol*m e o" reactor

Model !*tlet concen tration nlet concent ration

;ontactin% pattern

=inds of impellers

$hapter )


' rotatin% impeller in a "l*id imparts "low and shear to it, the shear res*ltin% "rom the "low o" one portion o" the "l*id past another.
a. #he three-bladed mixin% propeller is modelled on the marine propeller b*t has a pitch selected "or maxim*m t*rb*lence. #hey are *sed at relati$ely hi%h speeds &*p to +00rpm( with low $iscosity "l*ids, *p to abo*t :000c. 3any $ersions are a$ailableL with c*to*t or per"orated blades "or shreddin% and breakin% *p l*mps, with sawtooth ed%es as on i%*re +0.2&%( "or c*ttin% and tearin% action, and with other than three blades. #he stabiliin% rin% shown in the ill*stration sometimes is incl*ded to minimie sha"t "l*tter and $ibration partic*larly at low liD*id le$els.b. #he t*rbine with "lat $ertical blades extendin% to the sha"t is s*ited to the $ast ma/ority o" mixin% d*ties *p to +00,000 ; or so at hi%h p*mpin% capacity. #he simple %eometry o" this desi%n and o" the t*rbines o" i%*res +0.2&c( and &d( has inspired extensi$e testin% so that prediction o" their per"ormance is

on

a more rational basis than that o" any other kind o" impeller.

c. #he horiontal plate to which the impeller blades o" this t*rbine are attached

$hapter )


has a stabiliin% e""ect. 4ackward c*r$ed blades may be *sed "or the same reason as "or type e. d. #*rbine with blades are inclined :1 &*s*ally(. ;onstr*ctions with two to ei%ht blades are *sed, six bein% most common. ;ombined axial and radial "low are achie$ed. Cspecially e""ecti$e "or heat exchan%e with $essel walls or internal coils.

e. ;*r$ed blade t*rbines e""ecti$ely disperse "ibro*s materials witho*t "o*lin%. #he swept back blades ha$e a lower startin% torD*e than strai%ht ones, which is important when startin% *p settled sl*rries. ". hro*ded t*rbines consistin% o" a rotor and a stator ens*re a hi%h de%ree o" radial "low and shearin% action, and are well adapted to em*lsi"ication and dispersion. g. lat plate impellers with sawtooth ed%es are s*ited to em*lsi"ication and dispersion. ince the shearin% action is localied, ba""les are not reD*ired. ropellers and t*rbines also are sometimes pro$ided with sawtooth ed%es to impro$e shear. b. ;a%e beaters impart a c*ttin% and beatin% action. Fs*ally they are mo*nted on the same sha"t with a standard propeller. 3ore $iolent action may be obtained with spined blades.

SH*F%

#he sha"t is $ital component o" the a%itator and "reD*ently limits its mechanical per"ormance. n addition to transmittin% torD*e, the sha"t *nder%oes bendin%, and i" not sti"" eno*%h or ri%idly s*pported, it may $ibrate badly and ca*se discom"ort to personnel or dama%e to the eD*ipment. #here"ore it m*st be analyed "or combined torsional and bendin% stresses, de"lection, and critical speed and m*st be selected to meet the limitin% criteria "or each. nadeD*ately in these respects can res*lt in "ail*re o" the sha"t by o$erstress, "ail*re o" the seal d*e to excessi$e sha"t bendin%, or "ail*re o" bearin%s d*e to wear or impact #orsional and bendin% stresses calc*lation

$O1P0I+?S

$hapter )


3ost a%itators with lon% o$erh*n% sha"t ha$e ri%id co*plin%s to connect the a%itator sha"t and the %ear red*cer o*tp*t sha"t. #he co*plin% "acilities shipment, installation, remo$al and ser$icin% o" the a%itators. 'ltho*%h it is an innoc*o*s appearance block o" metal, care in its desi%n and "abrication can contrib*te si%ni"icantly towards the satis"actory per"ormance o" the a%itator. #he reasons "or this become mani"est "rom the reD*irement that the ri%id co*plin% m*st meet

$hapter )


$hapter )


+- the co*plin% m*st be capable o" transmittin% the a%itator torD*e 2- the co*plin% m*st pro$ide at least as m*ch ri%idity as the sha"t i" the critical speed o" the a%itator is not to be red*ced . - the co*plin% m*st stron% eno*%h to withstand the bendin% moments imposed *pon it by the *nbalanced hydra*lic and centri"*%al "orce. :- #he co*plin% m*st pro$ide %ood ali%nment between the sha"ts bein% connected 1- 4eca*se it m*st be assembled and disassembled in the "ield, "reD*ently *nder incon$enient workin% condition, the co*plin% sho*ld be relati$ely easy to take apart and reassembled, and sho*ld pre"erably be sel"-ali%nin%. 6- #he co*plin% m*st be capable o" takin% the thr*st d*e to wei%ht o" the a%itator.

'RAFT T,S ' dra"t t*be is a cylindrical ho*sin% aro*nd and sli%htly lar%er in diameter than the impeller. ts hei%ht may be little more than the diameter o" the impeller or it may extend the "*ll depth o" the liD*id, dependin% on the "low pattern that is reD*ired. Fs*ally dra"t t*bes are *sed with axial impellers to direct s*ction and dischar%e treams. 'n impeller-dra"t t*be system beha$es as an axial "low p*mp o" somewhat low e""iciency. ts top to bottom circ*lation beha$ior is o" partic*lar $al*e in deep tanks "or s*spension o" solids.

$hapter )


calculations

odi*m hydroxide concentration calc*lation

)a! added O +0.616 ?%mol O :26.21 ?% Water added O 66.: ?%mol O ++96.61 ?% =ensity o" )a! O +02.7 ?%A3 =ensity o" water O 997?%A3 #otal $ol*me o" the mixt*re O +H2Hd where+ is partial $ol*me o" )a! 2 is partial $ol*me o" water d is chan%e in $ol*me d*e to sol*bility



O

:26.21 ---------- H +02.7

++96.61 ----------997

O +.6+7 3 &eactor (olume and dimensions calculations

O

O

;'0

+0.616 ----------+.6+7 6.19 ?%molA3

O 6.19 %molAlit

 Va -------- O --------- O :2 a0 - >a  O 0.+22R21R:2 O +.011 3

&"rom %raph(

$hapter )


 O

2.+

&10E reactor is "illed(

pro$e it

L 4asic eD*ation *sed "or calc*latin% reactor $ol*me O

∆V' " O '0 &------------( - r ' " O +.1 m

" O $ol*me o" "l*id

 O 2.+ m &7E "ill(

 O $ol*me o" $essel

= O +.2 m

= O diameter o"

$essel  O +.2 m

 O hei%ht o" "l*id

< O len%th o" $essel

Selection and !eometry of Impeller  selected the 00 c*r$ed, sD*are pitched t*rbine blade with the Followin! specifications;

-+ O =aA=t -2 O CA=t - O
O 0. O 0. O 0.21 O 0.20 O 0.0 O +.00 &no clearance, not twisted b*t ad/acent with wall o" the $essel (

Power calculation;  O) p0&)r (&=a(1ρ O ?t &)r (&=a(1ρ O 0.: ?w O0.:1 hp

$hapter )


O 0.11 &2 E e""iciency o" the motor(

SH00 %HI$=+SS ri

+ ;c

V

O

&C / − 0.6  (



O

ress*re o" system

O

>adi*s o" shell



O

tress o" material

C /

O

C""iciency o" /oint

;s

O

;orrosion rateik

r i

V

+0+.,× 7.7 × +.292

O

+60000 × 0.-1 − 0.6 × 7.7 ×+0+.,

O

1.102 mm

+ 0.002

H*D %HI$=+SS ress*re at the lease

O

ρ%h

O

+00.:6 X 9. X :.:

O #otal press*re at base

O

t

O

:6.907 ?a 27.697 ?a i = i 2  C /

−

O -27.69 ×+.92 2 ×+60000 × 0.-1 − 0.2

×

-27.69

O

1.: mm

0.2 

$hapter )


ower n*mber, ),  %,A)=1p, a%ainst >eynolds n*mber, )>e  )=pAp, "or se$eral kinds of impellersL &a( helical shape (Oldshue, 1983); &b( anchor shape (Oldshue, 1983); &c( se$eral shapesL &+( propeller, pitch eD*allin% diameter, witho*t ba""lesB &2( propeller, s  d, "o*r ba""lesB &( propeller, s  2d, witho*t ba""lesB &:( propeller, s =2d, "o*r ba""lesB (5) t*rbine impeller, six strai%ht blades, witho*t ba""lesB &6( t*rbine impeller, six blades, "o*r ba""lesB &7( t*rbine impeller, six c*r$ed blades, "o*r ba""lesB &( arrowhead t*rbine, "o*r ba""lesB &9( t*rbine impeller,inclined c*r$ed blades, "o*r ba""lesB &+0( two-blade paddle, "o*r ba""lesB &++( t*rbine impeller, six blades, "o*r ba""lesB &+2( t*rbine impeller with stator rin%B &+( paddle witho*t ba""les &data o" 3iller and 3ann(B &+:( paddle witho*t

$hapter )


ba""les &data o" White and *mmer"ord(. 'll ba""les are o" width 0.+= [after Rushton, Costich, and Eerett, ;hem. Cn%. ro%. !"(9), !"# (1950)l.

$hapter )


Specification Sheet Identification;

tem L tem noL )o.reD*iredL

;#> & ;ontin*o*s low tirred #ank >eactor( >-0+ 0+

Function;

ormation o" sodi*m phenate "rom carbolic acid and ca*stic soda Operation;

;ontin*o*s %ype;

'%itator cylindrical $essel Desi!n Data; 8essel;

Workin% ol*me =esi%n ol*me #em perat*re &rocess temperat*re( =esi%n #emperat*re Workin% ress*re =esi%n ress*re =ia o" essel ei%ht o" $essel Workin% hei%ht ei%ht to dia ratio #ype o" head #hickness o" cylindrical protion #hickness o" bottom head )o. o" ba""le Width o" 4a""le ei%ht o" ba""le

+.1 m +.6 m 99Y; +09Y; + atm +.1 atm +.2 m +.16 m +.2 m +. #orispherical

$hapter )


*!itator; Followin! specifications; S-) < DaADt S-2 < ADt S-6 < 0ADa S-7 < 3ADa S-@ < >ADt S- < HADt +o, of baffles < 7

< < < < < < 9no

B,66 B,66 B,2@ B,2B B,BC66 ),BB clearance4 not twisted but adEacent with wall of the (essel :

$hapter )


Flash tan' desi!n $he na%e ori%inate "rom the "act that a liD*id at a press*re eD*al to or %reater than its b*bble point press*re "lashes or $apories, when the press*re is red*ced below its b*bble point press*re prod*cin% two phase system o" liD*id and $apor in eD*ilibri*m.

"asic e#uations used in flash calculation are

?i OUiAVi

+ &material balance eD*ation(

$hapter )


Where ?i eD*ilibri*m constant Ui $apor phase composition Vi liD*id phase composition

rom >a*lts and enry
Uiϕi O ViZiisat

ϕ O + "or low to moderate press*re Zi O + ass*mption as no data is a$ailable in literat*re

Ii ?i Ui O

---------------------+H&?i 8 +(

Ii Vi O

----------------------+H &?i 8 +(

"or "lash calc*lation necessary condition

 dew    b*bble ery important eD*ation *sed in "lash calc*lation

ϕi

Zi - Zidew ---------------Zi b*bble -Zidew

O

-

ϕidew

----------------

ϕ b*bble - ϕidew -+

 8  dew O

--------------------

 b*bble - dew

$hapter )


O

--------------0

- +  8  dew O

---------- b*bble - dew

 

O

-

 dew

-------------------- b*bble 8  dew

 b*bble

O

V++sat HV22sat \\..

+ 

O

dew

-----------------U+A+satHU2Asat \

Throttling Valves Globe Valve is an economical throttling valve. Its heavy duty design provides for long service life. The in-line globe design causes

relatively

high

pressure

drops,

however this is a desirable valve due to its economy and reliability.

eat*res 1- Slow closing - !revents water hammer in !V" piping

$hapter )


#- $eavy %uty "onstruction &- 'ong service life (-e)cient throttling with minimum wire drawing or dis* or seat erosion +-available in multiports- short dis* travel and fewer turn to operate, saving time an% wear on stem and bonnet

$hapter )


>et Eector #he two most common e/ectors are operated by water or steam. #he liD*id e/ectors are *sed "or creatin% a modest $ac**m or "or mixin% liD*ids. #he steam e/ectors is important in creatin% and holdin% a $ac**m in a system. C/ectors ha$e no mo$in% parts and operated by the action o" one hi%h press*re steam entrainin% and other $apors &or liD*ids( at low press*re into a mo$in% stream and thereby a remo$in% them "rom the process system at an intermediate press*re

Feature C/ectors ha$e the "ollowin% "eat*res which make them %ood choice "or contin*o*sly prod*cin% economical $ac**m condition.

+- #hey handle wet, dry or corrosi$e $apor mixt*res 2- #hey de$elop any reasonable $ac**m needed "or ind*strial operation. - 'll sies are a$ailable to match any small or lar%e capacity reD*irement. :- #heir e""iciencies are reasonable to %ood. 1- a$e no mo$in% parts, hence maintenance low, operation "airly constants when corrosion is not a "actor. 6- T*iet operation. 7- table operation within desi%n ran%e - nstallation cost relati$ely low when compare to mechanical $ac**m p*mps. 9- pace reD*irement is small +0- imple operation.

%ypes C/ectors may be sin%le or m*lti-sta%e. #he extra sta%es, with or witho*t inter sta%e condensin% o" steamB allow the system to operate at lower

$hapter )


absol*te press*re than a sin%le sta%e *nit. ario*s combinations o" series o" /ets with no inter-condensin% can be connected to /ets with inter-condensers or a"ter condensers to obtain $ario*s types o" the operation and steam economy.

Material of construction ince the e/ector is basically simple in constr*ction, it is a$ailable in many material s*itable "or handlin% corrosi$e $apors. tandard materials incl*de cast iron, meehanite, cast steel, and brone "or the body and di""*sers dependin% *pon the press*re and temperat*re ratin%. #he nole is *s*ally stainless steel or monel. !ther material o" constr*ction incl*de porcelain, carbon %raphite, impre%nated %raphite, synthetic resins, %lass and special metal o" all types

DMIS%&S O& IMPI+?+% SP*&*%O&

's the descripti$e name s*%%ests, the impin%ement separator allows the particles to be remo$ed to strike some type o" s*r"ace. #his action is better accomplished in press*re system where press*re drop can be taken as a res*lt o" t*rb*lence which necessarily accompanies the remo$al action. articles remo$ed in stream line "low is less e""icient than "or t*rb*lent "low and not be e""ecti$e i" the path o" tra$el is not properly well ba""led. #here is basically three constr*ction type "or impin%ement separators. +-wire mesh 2- lates &c*r$ed, "lat or special shaped( -packed impin%ement beds ' demister pad resembles a %iant brillo pad with the soap. 3any process plants ha$e discarded demister pads lyin% aro*nd their scrape heaps. #he theory o" operation o" demister is simple. apors and droplets o" liD*ids strike the demister pad with a s*stainable $elocity. #he "orce o" this impin%ement $elocity ca*ses the tiny droplets. #he hea$ier droplets o" liD*id to coalesce into lar%e droplets.

$hapter )


or knocko*t dr*m with a demister pad it apparently m*st ha$e ?-$al*e o" at least 0.+1 to 0.20 When a demister pl*%s it increases the press*re drop o" the $apor, b*t press*re drop cannot increase a lot beca*se the demister will break. =emister "ail*re creates two problems. +- #he dislod%ed section o" the demister pad are blown into down stream eD*ipment as into s*ction o" the centri"*%al wet %as compressor 2-the "ailed demister promotes hi%h localied $elocities. apors blows thro*%h the open areas o" the $essel. #he remainin% section o" the demister pad impedes $apor "low. #he res*ltin% hi%h localied $elocities o" $apors creates more entrainment than we co*ld ha$e witho*t any demister

Steam trap ' steam trap is sel" act*atin% a*tomatic drain $al$e in a steam distrib*tion system that per"orms the "ollowin% "*nctions. +- >emo$al o" condensate 2->emo$e air or other noncondensible %ases - re$ents or limits the loss o" steam ;ondensate &water( is "ormed when steam condenses to release latent heat. ome heat is released in the distrib*tion system in the "orm o" *na$oidable losses. 3ost o" the heat is *tilied in the process eD*ipment. !nce steam has condensed, the hot condensate m*st be remo$ed immediately as it hinders e""ecti$e heat trans"er "rom the incomin% steam. 4y selecti$ely p*r%in% a steam system o" its condensate and noncondensible, steam trap helps maintain hi%h heat trans"er coe""icient in eD*ipment witho*t losin% li$e steam n the recent years *ser interest in steam trap has closely paralleled the increase in ener%y cost. i%h "*el cost associated with the mal"*nctionin% trap cannot be i%nored. piralin% cost ha$e hi%hli%hted the need "or optim*m steam trap selection and application. Cxperience indicates that improper selection and

$hapter )


application are the most "reD*ent ca*se o" the trap "ail*re and steam loss. #he installation or the replacement o" steam trap has a pay back period o" as little as three to six months.

$lassification of steam trap #here are three basic type o" steam traps *sin% di""erent physical principle to distin%*ish between steam and condensate.

%hermostatic steam trap

#hese traps are act*ated by the temperat*re sensiti$e which operate on the basis that the steam is hotter than condensate, air, and other noncondesibles. #here are three types o" thermostatic traps. +-

2-

4alanced press*re

-

4imetallic

Mechanical steam trap

#hese traps operate on the di""erence o" density between steam and condensate. #he two important type o" mechanical steam traps are +-

ball "loat

2-

b*cket

%hermodynamic steam trap

#hese traps are operates on the "acts that "lash steam is prod*ced when press*re is red*ced on the hot condensate. #he release o" "lash steam ca*ses the dischar%e to close. #here are the "ollowin% "*rther types. +- =isk type 2-

iston type

-

$hapter )


FLASH #AL#,LAT/$N data tempe"at#"e .p.o+ !ate"Ka .p.o+ .p.o+ phenol Kpa .p.o+ p.o+

100 101.33

"uid composision name compo&'t'on !ate" 0.87

3.51

phenol Na-

0.0137

heKa

2.07

he

0.1182

/#// /#//lle Kpa *e! Kpa

88.4 88.45 5 14.36

NaNa-

apo" 0.856391

l'#'* 0.1436 43609

compo&'t'on 0.975529 0.00729 0.0139688 1.028442

comp. 0.0220693 0.051924 0.871002 0.945

K0RS,R Kpa component 25 !ate" phenol Na-he

al#e& 4.053 0.1404 0.0828

' 0.9786 0.007089 0.014361 1

#otal #otal mole "or 21-ton per day O .1616R21 O 222+.: ?%mol

#otal #otal moles in tank

O

#otal #otal wei%ht

O +.991&0.9R++6H0.06+R9:H0.02+(

O

+.991 ?%mol

129.:+ ?%

Wei%ht We i%ht reD*ired "or +.1-batch o" a*tocla$e O 129.:+A: O 2.1 ?%

'$era%e density O 0.90R+21H0.06+R+02H0.02R99:

O

+222.21 ?%Am

' 0.028531 0. 0.061549 0.9099 1

$hapter )


illed $ol*me

O 7.2+7: m

E "ill total $ol*me

O :1 E O +6 m < O 1m , = O 2m

ome more speci"ications ei%ht o" liD*id

O

ei%ht o" inlet pipe

O

ei%ht o" demister pad O #hickness o" demister pad O 3aterial o" demister pod

O

ei%ht o" o*tlet

O

team press*re

O

DSI?+ OF DIS%I00*%IO+ $O01M+ #he detailed process desi%n o" the carbolic acid col*mn is %i$en below. #he pictorial >epresentation o" the col*mn is %i$en in "i%. #he "eed to the col*mn is a mixt*re o" carbolic carbolic acid and sodi*m phenolate. #he compositions o" the

$hapter )


components are %i$en below. #he top and bottom prod*ct, both a re the reD*ired prod*cts *sed in reactor one and in a*tocla$e &second reactor(.

. #hermodynamicsL #he primary reD*irement while desi%nin% mass trans"er contact eD*ipment is the #hermodynamic eD*ilibri*m data. #he data reD*ired is in the apor-
�i

O acti acti$i $ity ty coe"" coe""ic icie ient nt o" comp compone onent nt i^ i^ in

liD*id. xi O mole "raction o" component i^ in liD*id. i sat O sat*ration $apor press*re o" component i^.

#he eD*ilib eD*ilibri* ri*m m $apor $apor press* press*re re was e$al*a e$al*ated ted *sin% *sin% correl correlati ations ons %i$en %i$en in literat*re. #he correlation was based on the critical properties o" the components. #he two components carbolic acid and sodi*m phenolate "orm a hi%hly non-ideal system. #o accommodate this nonideality, an acti$ity coe""icient term was *sed "or the liD*id phase. #he acti$ity coe""icient was e$al*ated *sin% the F)'; model. ince the e$al*ation o" the 
$hapter )


components reD*ire the col*mn to be operated at + atmosphere. #he operatin% press*re was chosen to be 760 mm % &abs(.

#he "ollowin% D*estions m*st be answered be"ore %oin% into detailed desi%n o" the distillation col*mn

+- what col*mn is selected packed or tray col*mn _

*nswer #ray col*mn wo*ld be better choice in sit*ation "acin% d*e to the "ollowin% reasons +- sta%e e""iciency can be determined experimentally in packed col*mn beca*se ` O"&type and siin% o" packin%, "l*id rates, "l*id properties, col*mn diameter, operatin% temperat*re and press*re, extent o" liD*id dispersion\\( Where as a n*mber o" correlations are a$ailable "or tray col*mn e""iciency disc*ssed by the "amo*s a*thors. ;o*lson and >ichardson, <*dwi%, erry, eter and #immerha*s, concept*al desi%n o" distillation col*mn and more\.. 2-tray col*mn can be desi%ned o$er a wide ran%e witho*t "loodin% -total dry wei%ht o" the tray col*mn is less than the packed col*mn :-desi%n in"ormation "or tray col*mn id readily a$ailable as compared to packed col*mn. #his made path o" workin% easy "or me when  decided tray col*mn 1-i" chances o" "oam "ormation are more then packed col*mn wo*ld be %i$en pre"erence, b*t in sit*ation "acin% me no "oam "ormation &s*r"ace tension at di""erent temperat*re and press*re wo*ld dictate "oam "ormation criteria( 6- #hermal expansion chances can be easily handled with tray col*mn instead o" packed col*mn.

$hapter )


7- CD*ilibri*m =ata "or lar%e compo*nds as well as my compo*nd are a$ailable in literat*re and this data is more reliable "or tray col*mn instead o" packed col*mn

What type o" tray is selected sie$e tray, b*bble cap, or $al$e tray _

*nswer  decided sie$e tray beca*se o" the "ollowin% reasons +- 3an*"act*rin% cost is low 2-operatin% cost is low -simple to constr*ct :-minm*m entrainment as compare to b*bble cap and $al$e tray 1-less press*re drop as compare to other 6-most commonly *sed

?lossary of notations used;  O molar "low rate o" eed, %m = O molar "low rate o" =istillate, %molAhr. W O molar "low rate o" >esid*e, %molAhr. x O mole "raction o" phenol in liD*idAeed. y= O mole "raction o" phenol in =istillate. xW O mole "raction o" phenol in >esid*e. 3 O '$era%e 3olec*lar wei%ht o" eed, %A%mol 3= O '$era%e 3olec*lar wei%ht o" =istillate, %A%mol 3W O '$era%e 3olec*lar wei%ht o" >esid*e, %Amol >>m O 3inim*m >e"l*x ratio >> O 'ct*al >e"l*x ratio <> O 3olar "low rate o" O 3olar "low rate o" apor in the Cnrichin% ection, %molAhr. < O 3olar "low rate o"
$hapter )


s O 3olar "low rate o" apor in trippin% ection, %molAhr. D O #hermal condition o" eed l O =ensity o"
µl O iscosity o"
eed O 99+1 %molAh x O 0.67, 3 O +0+.+6%A%mol. = O 67.9%molAhr, x= O 0.97, 3= O 9:.66%A%mol. WO++.+%molAhr, xW O 0.02, 3W O++1.16%Amol. "asis; ) Hour Operation .

rom the %raph >m O +.1 O 2.+ R>m estimated ( >>O +.1X2.0O .2 )*mber o" deal trays O +7 )*mber o" deal trays in Cnrichin% ection O  )*mber o" deal trays in trippin% ection O 9 )ow, we know that, >> O >A =

O > O>>X= i.e., >O .2R67.9 O 2+701%molAh

> O < H =

&"rom trial this $al*e is

$hapter )


O &>H+(R= O :.2R67.9molAhr O 2:.6%molAh > O 5as "low rate in the Cnrichin% ection O 2:.6%molAh ince "eed is < O 99+1H2+701.6O+6+9.6 %molAh #here"ore, liD*id "low rate in the trippin% ection O +6+9.6 %molAh 'lso, we know that,  O [&D-+( X] H >  O [&+-+( X] H >  = >

O

O 2:.6%molAh

#here"ore, the "low rate o" apor in the trippin% ection O O 2:.6%molAh

I8, Desi!n Specification; %ray Hydraulics

#he desi%n o" a sie$e plate tower is described below. #he eD*ations and correlations are borrowed "rom the 6th and 7th editions o" erryKs ;hemical Cn%ineersK andbook, plant desi%n and economics by eter and #immerha*rse, l*dwick, *nit operation o" chemical en%ineerin% by 3c;abe and mith, ;o*lson and >ichardsonKs book, separation techniD*es by ;.5. ?in% #he proced*re "or the e$al*ation o" the tray parameters is iterati$e in nat*re. e$eral iterations were per"ormed to optimie the desi%n. #he "inal iteration is presented here. +. #ray pacin%, &ts(L
$hapter )


. ole itch &lp(L atio o" hole area to per"orated area &'hA'p(L >e"er "i% 6.)ow, "or a trian%*lar pitch, we know that >atio o" hole area to per"orated area &'hA'p( O  &A:Xdh2(A [&√A:( Xlp2] i.e., &'hA'p( O 0.90X &dhAlp(2 i.e., &'hA'p( O 0.90X &1A+1(2 i.e., &'hA'p( O 0.+ #h*s, &'hA'p( O 0.+ . Plate Diameter 9Dc:;

#he plate diameter is calc*lated based on the "loodin% considerations
;sb, "lood O 0.07 mAs.

Fn" O ;sb, "lood X & A 20( .0.2 [&ρ l - ρ %( A ρ %] 0.1---- QeDn. +.2, pa%e

+.6, 6th edition erry.S

$hapter )


&lant desi%n and economics by eter and #immerha*s(

Where, Fn" O %as $elocity thro*%h the net area at "lood, mAs &"tAs( ;sb, "lood O capacity parameter, mAs &"tAs, as in "i%.+.+0(  O liD*id s*r"ace tension, m)Am &dyneAcm.(

ρ l O liD*id density, k%Am &lbA"t( ρ %

O %as density, k%Am &lbA"t(

)ow, we ha$e,  O 2.17 dyneAcm. l O +02 k%Am. % O 2.12 k%Am. #here"ore, Fn" O 0.07X &2.17A20(0.02 R[97-2.12(A 2.12]0.1 i.e., Fn" O :.7 "tAs O +.:9 mAs.
'ct*al $elocity, FnO 0.XFn" i.e., Fn O +.+9 mAs

)ow, $ol*metric "low rate o" apor Do O 2:.6R9:.1 A &600X2.12R+000( O 0. mAs. )et area a$ailable "or %as "low &'n( )et area O &;ol*mn cross sectional area( - &=own comer area.( 'n O 'c - 'd #h*s,

)et 'cti$e area, 'n O DoA Fn O 0.A+.++9 O 0.212 m2.

Where,
,

c O 2Xsin-+&
$hapter )


'nd,

c O an%le 'd O [&3.14A:( X =c2 X & c A600(] - [&
&97.+0(] 'd O &0.2+96X =c2( - &0.+2:+X =c2( 'd O 0.0911X=c2, m2 ince,

'n O 'c -'d 0.212 O &0.71:X=c2( - &0,0911X =c2( i .e., 0.691X =c2 O 0.212 =c2 O 0.212A 0.691 O 0.61 =c O 0.6 m

#ake =c O 0.61 m ince
)ow,

'd O 0.079X0.61 O 0.01: m2 'n O 'c - 'd 'n O0.+6-0.01: *n < ,2CB m 2 , Perforated plate area 9*p:;

'cti$e area &'a( 'a O 'c - &2X'd( 'a O 0.+6- &2X0.01:( *a < B,27@ m2

O 97.+ 0.

c O an%le

$hapter )


+O+0 0 - 97.+ 0 O 2.2 0

+ O

an%le 'c O 2X
ince, 'h A 'p O 0.+ 'h O 0.+X 'p 'h O 0.+X 0.+7: O0.0+7:m2 #h*s, #otal ole 'rea O 0.0+7: m2 )ow we know that, :R'h O nh X & .fdh2(

Where nh O n*mber o"

holes. nh O &:X0.0+7:(A &.3.14X0.0012(

⇒

nh O 909

#here"ore, )*mber o" holes O GBG, G, 3eir Hei!ht 9hw:;

$hapter )


'll the press*re drops calc*lated in this section are represented as mm head o" liD*id on the plate. #his ser$es as a common basis "or e$al*atin% the press*re drops. +otations used and their units;

hd O ress*re drop thro*%h the dry plate, mm o" liD*id on the plate *h O apor $elocity based on the hole area, mAs how O ei%ht o" liD*id o$er weir, mm o" liD*id on the plate h O ress*re drop d*e to b*bble "ormation, mm o" liD*id hdsO =ynamic seal o" liD*id, mm o" liD*id hl O ress*re drop d*e to "oamin%, mm o" liD*id h" O ress*re drop d*e to "oamin%, =" O '$era%e "low len%th o" the liD*id, m >h O ydra*lic radi*s o" liD*id "low, m *" O elocity o" "oam, mAs &)>e( O >eynolds n*mber o" "low " O riction "actor hh% O ydra*lic %radient, mm o" liD*id hda O
hd O head loss across the dry hole hd O k+ H [k2X &%Al( XFh2] --------- &eDn. +.6, pa%e +.9, 6th edition erry(

$hapter )


where Fh O%as $elocity thro*%h hole area k+, k2 are constants or sie$e plates k+ O 0 and k2 O 10. A &;$(2 where ;$ O dischar%e coe""icient, taken "rom "i%. +.+:, pa%e +.9, 6th edition erry(. )ow, &'hA'a( O 0.0+7:A 0.2:1 m2 O 0.07 also t#Adh O A1 O 0.60 #h*s "or &'hA'a( O 0.0799 and t#Adh O 0.60 We ha$e "rom "i%. edition +.+:, pa%e +.9 6th erry. $( < B,6B

k2 O 10, A 0,702 O G@,62@ ol*metric "low rate o" apor at the top o" the Cnrichin% ection Dt O 0. mAs. elocity thro*%h the hole area &Fh(L elocity thro*%h the hole area at the top O Fh, O Dt A'h O 0.A0.0+7: O +6. mAs elocity thro*%h hole area sho*ld be minim*m beca*se at low %as "low rate weepin% is obser$ed. )ow, hd, O k2 [%Al] &Fh (2 O 91.271.&2.9+A+0++( +6.2 hd, top O 1.2: mm clear liD*id. -------&minim*m at top(

$hapter )


Head 0oss Due to "ubble Formation

h O :09 [ A &ldh(] --- &eDn. +.2.a, pa%e +.7, 6th edition erry( where = s*r"ace tension, m)Am &dyneAcm( dh Oole diameter, mm l O a$era%e density o" liD*id in the section, k%Am O &97H++:+(A2 O +06: k%Am h O:09 [+7.:161 A&777.92 x1(] h O 2.7+: mm clear liD*id Hei!ht of 0i#uid $rest o(er 3eir;

how O 66: )w [&DA
$hapter )


pa%e +.++, 6th edition erry wO correction "actor O+.021 how O +.021.66:. [&6.2:9.+0-(A+.:21]2A how O +.2 mm clear liD*id. )ow, &hd H h( O 1.2: H 2.7+: O 7.91 mm ------ =esi%n $al*e &hw H how( O :1 H +.2 O 6.2 mm 'lso, 'hA'a O 0.0 and &hw H how( O 6.2 mm #he minim*m $al*e&hd H h( o" reD*ired is calc*lated "rom a %raph %i$en in erry, plotted a%ainst 'hA'a. we ha$e "rom "i%. +.++, pa%e +.7, 6th edition erry &hd H h( min O +6.0 mm ------- #heoretical $al*e. #he minim*m $al*e as "o*nd is +6.0 mm. ince the desi%n $al*e is %reater than the minim*m $al*e 4 there is no problem ofweepin!, Down comer Floodin!;

hds Ohw H how H &hh% A2( ------- &eDn +.+0, pa%e +.+0, 6th edition erry( Where,hw O weir hei%ht, mm hds O static slot seal &weir hei%ht min*s hei%ht o" top o" slot abo$e plate "loor, hei%ht eD*i$alent clear liD*id, mm( how O hei%ht o" crest o$er weir, eD*i$alent clear

$hapter )


liD*id, mm hh% O hydra*lic %radient across the plate, hei%ht o" eD*i$alent clear liD*id, mm. n the abo$e eD*ation how is calc*lated at bottom o" the section and since the tower is operatin% at atmospheric press*re, hh% is $ery small "or sie$e plate and hence ne%lected. $alculation of how at bottom conditions of the section;

D O liD*id rate at the bottom o" the section, mAs O +6+9R++6A&600R+21R+000(O.+x+0-: mAs O &.+x+0-:(A &6.09R+0-( O 7.7 %alAmin
Where %a O %as-phase

kinetic ener%y "actor, Fa O s*per"icial %as $elocity, mAs &"tAs(, % O %as density, k%Am &lbA"t( ere Fa is calc*lated at the bottom o" the section.

$hapter )


Fa O &5bA%(A 'a O &2072A2.9+( A&0.2:1x600( O +.2: mAs #h*s, Fa O :.06 "tAs % O 2.9+ k%Am O 2.9+A &+.60+:6.+0-+( O 0.++ lbA"t %a O :.06. &0.++(0.1 %a O +.72 )ow "or %a O +.72, we ha$e "rom "i%. +.+1, pa%e +.+0 6th edition erry( 'eration "actor O β O 0.6 >elati$e roth =ensity O ϕt O 0.20 )ow hlKO β∗ hds ---- &eDn. +., pa%e +.+0, 6th edition erry( Where, hlKO press*re drop thro*%h the aerated mass o$er and aro*nd the disperser, mm liD*id, hlKO 0.6∗ 6:. O .19 mm. )ow, h" O hlAϕt ------- &eDn. +.9, pa%e +.+0, 6th edition erry( h" O .19A 0.20 O +92.99 mm. Head loss o(er down comer apron;

hda O +61.2 QDA 'daS2 ----- &eDn. +.+9, pa%e +.+0, 6th edition erry( Where, hda O head loss *nder the down comer apron, as millimeters o" liD*id, D O liD*id "low rate calc*lated at the bottom o" section, mAs and 'da O minim*m area o" "low *nder the down co mer apron, m2 )ow, D O +910.0A&600.776.9( O 6.77:.+0- mAs #ake clearance, ; O +A2^ O +2.1 mm hap O hds - ; O 6:. 8 +2.1 O1+. mm 'da O
$hapter )


hda O +61.2[6.77:.+0- A 2:.6x +0-] 2 O +2.71 mm ht O total press*re drop across the plate &mm liD*id( O hd H hl O 1.2: H .19 O +2. mm Down comer bac'up;

hdc O htH hw H how H hda H hh% ---- &eDn +., pa%e +.7, 6th edition erry( Where, hdc O hei%ht in down comer, mm liD*id, hw O hei%ht o" weir at the plate o*tlet, mm liD*id, ho Ohei%ht o" crest o$er the weir, mm liD*id, hda O head loss d*e to liD*id "low *nder the down comer apron, mm liD*id, hh% O liD*id %radient across the plate, mm liD*id. hdc O+2. H :1 H +9. H +2.71 H 0 O 20+ mm
8, FFI$+$IS; 9*I$h Method:

*: nrichin! Section;

Point fficiency4 9o!:;

Co% O +-exp &-)o%( ----- &eDn. +., pa%e +.+1, 6th edition erry( Where )o% O !$erall trans"er *nits

$hapter )


)o% O +A [&+A)%( (,Nl(] ---- &eDn. +.:, pa%e +.+1, 6th edition erry( Where )l O
 O&mX5m(A
$hapter )


)l O klX aXl ----- &eDn +.6a, pa%e +.+1, 6th edition erry( Where kl O
+O residence time o" liD*id in the "roth or spray, s  l O &hlX'a(A&+000XD( ---- &eDn. +., pa%e +.+6, 6th edition erry( D O liD*id "low rate, mAs O 1.7+R+0-: mAs hl O hlK O .0 mm 'a O 0.:7 m2 l O &.0X0.:7 (A&+000X1.7+R+0-:( O+.: sec kl Xa O &.71X+0X=<(0.1X &&0.:0XFaX%0.1( H 0.+7(--- &eDn. +.:0a, pa%e +.+6, 6th edition erry( =
$hapter )


Co% O 0.67

∴ Point fficiency < o! < B, 2, Murphree Plate fficiency 9m(:;

)ow, elect n*mber O)e O Il2A &=CX l( Where Il O len%th o" liD*id tra$el, m =C O &6.671 x +0-X &Fa(+.::( H &0.922 X +0 -:X hl( - 0.00162 ----- &eDn. +.:1, pa%e +.+7, 6th edition erry( where =C O Cddy di""*sion coe""icient, m2As =C O &6.671 x +0 -X &+.266(+.::( H &0.922 X +0 -:X .0( - 0.00162 =C O 7.261X+0- m2As 'lso Il O =cX cos &cA2( O 0.61X cos &97.+ 0A2( O 0.:6 m )e O Il2A &=CX l( O 0.:62A &7.261X+0- X 17.+( )e O 1.+ j XCo% O 0.76 x 0.67 O 0.102

no! +o" jXCo% O 0.60 and )e O 1.+ We ha$e "rom "i%.+.29a, pa%e +.+, 6th edition erry 'lso a$ailable in se$enth edition Cm$A Co% O +.2 Cm$ O +.2X Co% O +.2X0.67 O0.+ Murphree Plate fficiency < m( < B,C) 6, O(erall fficiency 9 O$:;

C!; O lo% [+ H Cg &j  - +(]Alo% j ----- &eDn. +.:6, pa%e +.+7, 6th edition erry(

$hapter )


Where Cg ACm$O +A&+ H C3 [ ψ A &+-ψ (]----- &eDn. +.27, pa%e +.+, 6th edition erry( Cm$ O 3*rphee apor e""iciency, C. O 3*rphee apor e""iciency, corrected "or recycle e""ect o" liD*id entrainment. &
ψ O "ractional entrainment, molesAmole %ross down "low O 0.076 Cg O Cm$ +A[+ H Cm$ [ψ A &+- ψ (]] O 0.+[&+H0.+[0.076A &+-0.076(](]

⇒ Cg O 0.77 !$erall C""iciency O C!; O lo% [+ H Cg &j - +(]Alo% j C!; O lo% [+H 0.770&0.76-+(]Alo% 0.76 !$erall C""iciency O C!; O 0.726 'ct*al trays O )act O )#AC!; O &ideal trays(A &o$erall e""iciency( Where )# O #heoretical plates, )act O act*al trays )act O +7A0.7262.:+O21 #h*s act*al trays in recti"yin% section O + #h*s, 'ct*al trays in the trippin% ection O +2 #otal ei%ht o" distillation col*mnO 21Xts O 21X:17 O ++:21 mm O ++.:21 m

Desi!n of autocla(e I+%&OD1$%IO+

$hapter )


'*tocla$es ha$e been *sed in ind*stry "or many decades. 's technolo%y has pro%ressed so has a*tocla$e desi%n, initially "rom basic ri$eted steam heated $essels to $essels "abricated *tiliin% the latest weldin% techniD*es with hi%hly sophisticated comp*teried control systems #he ind*stries that make *se o" a*tocla$es ha$e also e$ol$ed o$er the years. nitially *sed in the textile, timber, "ood, steriliin% and r*bber ind*stries, a*tocla$es are now essential items in the ad$anced composites and n$estment castin% ind*stries ;ommercial press*re a*tocla$es ha$e been in operation since mid +910s. istorical prod*ction data s*%%est that these early a*tocla$es were ori%inally desi%ned with excess capacity &4ere owsky, ;ollins, ?er"oot, and #orres, +99+(. rocess de$elopment initially consisted o" tests in batch a*tocla$es. While in some cases this sta%e had been "ollowed by contin*o*s pilot plant tests in m*lti-compartment a*tocla$es, in many cases the batch test residence times were extended to the contin*o*s commercial sta%e *sin% some "actor, res*ltin% in an o$er estimation o" the reD*ired a*tocla$e $ol*me. n some other instances the contin*o*s sta%e o" testin% had not been per"ormed or its res*lts co*ld not be interpreted as a contin*ation o" batch tests d*e to di""erences in ore composition, %rind sie and reactor conditions. n s*ch cases, it wo*ld be important to be able to scale-*p the batch test data to a m*lti-compartment contin*o*s mode *sin% a so*nd approach that takes into acco*nt both the physical and chemical aspects o" the leachin% reaction as well as the reactor con"i%*ration.

or *se in the prod*ction o" ad$anced composite materials, a hot atmosphere a*tocla$e has to achie$e the "ollowin% criteriaL

•

ail to sa"ety, sa"ety systems

•

'chie$e the reD*ired internal en$ironment &ie. h eat and press*re(

$hapter )


•

ro%rammable temperat*re control and *ni"orm temperat*re distrib*tion

•

ro%rammable press*re control

•

;omp*terised process control, monitorin% and data lo%%in%

)ot only the a*tocla$es are made o" a no. o" di""erent materials,b*t the siea,%eneral desi%n and arran%ement "or heatin% are so $aried that one mi%ht "or%i$e a chemist,*sed only to most common "orms,"or "ailin% to some o" the rare types o" modern apparat*s as bein% a*tocla$e at all. #wo partic*lar types o" a*tocla$es ha$e beenselected as co$erin% the most important ran%es o" hi%h press*re work.#hese are +. i%h press*re a*tocla$es 2.
$hapter )


3any o" the di""erent materials, are *sed "or packin% o" the /oints. #he commonest packin%s are lead,copper,al*mini*m and asbestos.)ot only does the choice o" material *sed on type o" a*tocla$e ,b*t also depend on press*re.t is more common one type to "ix one or more sa"ety $al$es o" the ordinary steam boiler type to an a*tocla$e.4*t these were constantly %ettin% chocked with material either distilled or splashed into the $al$e. ndeed, there is no possibility o" chemical reaction between the char%e and the material o" which a*tocla$e, i" it is do*bt"*l the *se o" liner is necessity. #he liner is a thin walled $essel to "it inside o" the a*tocla$e and intended to hold the char%e. #he liner may be made o" lead, steel tin, copper, iron, or sometime inc.

F*$%O&S *FF$%I+? *1%O$0*8 SI/

n a recent paper on desi%n o" a*tocla$es "or press*re leachin% o" nickel literates &?in%, +996(, the "ollowin% ha$e been listed as the determinin% "actors in the press*re a*tocla$e sieL solids thro*%hp*t and sie distrib*tion +.

selected a*tocla$e circ*it

2.

sl*rry density

.

retention time

:. temperat*re 1.

n*mber o" operatin% trains

6.

shippin% restrictions.

$hapter )


Desi!n $alculations M*SS I+; )a!

O

21.91 k%

2!

O

+:1.6 k%

henol

O

:20.2 k%

)a-henolale

O

1066. k%

;!2

O

20:.6:

#otal mass

O

796.9 k%

Desi!n; '$era%e density o" "l*id

O

ρsoln O +00.:6 k%Am

ol*me o" reactant

O

 O mAρsoln

O

7. m



O

+0.2 m

A=

O

2.

#otal

O

cylinder shell H ellipsoidal head

+0.2

O

π =2 + π

=,

O

π = 2 & 2.,=(

+

=

O

+.92 m



O

2. =

O

:.: m

:0E desi%n allowance

⇒

$*0$10*%IO+S FO& *?I%*%O&

:

:

2:

π 2:

=,

$hapter )


%ype; %urbine Pitched "lade i(

=iameter o" impeller

O

=a O +.92A

ii(

O

0.6:

iii(

ei%ht o" impeller "rom bottom

O

a O 0.6: m

i$(

mpeller blade width

O

$(

o*r $ertical ba""les width

O

=t +1 =t +0

O 0.+2 m

O 0.+92 m

PO3& $O+S1MP%IO+ O

)p )r =a1

O

+200 "tAmin.

#s

O

π X =a X )r

+200

O

.+: X &0.6: X .2( X )r

)r

O

++. rAmin.

O

.0 rAsec.

 #s O #ip speed

>e

O O

= a2 × )r × ρ 0.29-

::99.+

>e is %reater than +0,000 so  is independent o" )p and )p

O

? #



O

1 , ?# = a )r ρ

O

+.61 X 0.6:1 X .0 X

O

1.21 ?w

O

1.21 X +.1

+00.:6

$hapter )


O

7.+ hp

C""iciency o" motor 0E, so ower reD.

7.+-0.-

O O

$*0$10*%IO+

OF

I+SID

FI0M

.9  O 9 ..

$O-FFI$I+%

FO&

&*$%O& or pitched blade t*rbine 0.,,

hi =t

O

0.62 ( ) >e )

; p &mixt*re(

O

2.+ ?A?%-?

µ &mixt*re(

O

0.29 a-sec.

? &mixt*re(

O

0.61 WAm2-?

O

0.62

?

hi 0.0006-1 +.92

0.67

× ( ::99-.+-) 0.67   

 ; p µ     ?  

X 0.,,

2.+ × 0.00029-  0.0006-1

 

0.16 ?@Am2 8 sec 8 ?

O

FI0M $O-FFI$I+% OF >*$=% We ha$e steam in /acket so h /

O

+100 4t*A"t2 8 hr 8 o

O

0.071 ?@Am2 8 sec 8 ?

O

n ;p ∆#

O

0.61 X 7 X +00

H*% "*0*+$ )a ! T

$hapter )


O

1070 ?@

O

.+ X 71.2: X +00

O

609::.: ?@

O

::.2 X 2:.+7 X +00

O

+07:++.: ?@

O

:.: X :1.7 X +00

O

20:7.6 ?@

O

0.62 X 217.76 X +00

O

7926+.+ ?@

O

+910160.12 ?@

2! T

)a 8 ph

h

)a 8 al

#otal heat reD.

%ime &e#, for Heatin!

ln

− #+ #s − #2

O

ln

2,1 − 220 2,1 − +20

O

#s

t

O

F' m ; p

&t (

0.0667 × 26 .1&t ( 796,.-9 × 2.+

2.76 hrs

Heat Flow &ate T

O O

3ass "low rate o" steam

+910160.12 2.76

70672:.2 ?@Ahr

$hapter )


T

O

 ; p ∆# m

70672:.2

O

 X 2.029 X +1 m

 m

O

2220.79 k%Ahr

O

6.:1 k%Asec.

O

F = ' <3#=

For Heat %ransfer *rea 

T

+ F= + F=

+

0.1-6

+

+

0.071,

O

+

hi

+

+

h/

+ V ?

O

+ 0.0011 0.0011 F=

O

0.0667 ?@Am2--?

T



O

F = ' <3#=

70672:.

O

0.0667 X ' X +70.:+

'

O

+7.27 m2

)ow

C""ecti$eness o" /acket

O O

M$H*+I$*0 DSI?+ SH00 %HI$=+SS

+7.27 26.1-

61.: E

$hapter )


ri

+ ;c

V

O

&C / − 0.6  (



O

ress*re o" system

O

>adi*s o" shell



O

tress o" material

C /

O

C""iciency o" /oint

;s

O

;orrosion rate

r i

V

+0+.,× 7.7 × +.292

O

+60000 × 0.-1 − 0.6 × 7.7 ×+0+.,

O

1.102 mm

+ 0.002

H*D %HI$=+SS O

ρ%h

O

+00.:6 X 9. X :.:

O

:6.907 ?a

#otal press*re at base

O

27.697 ?a

t

O

ress*re at the lease

i = i 2  C /

−

O -27.69 ×+.92 2 ×+60000 × 0.-1 − 0.2

×

-27.69

O

1.: mm

0.2 

$hapter )


$hapter )


*$IDIFI$*%IO+ %*+= When the reaction in a*tocla$e is completed the o*tcome stream is at #emperat*re o" +21 ;o and it needs to be cooled to approach the acidi"ication temperat*re reD*irement. o this stream is passed thro*%h dil*tion tank where alon% with lowerin% o" temperat*re to 6 ;0, the dil*tion o" "eed "or reactor is carried o*t to %et maxim*m con$ersion. #hen this stream containin% reactant sodi*m salicylate enters into the 'cidi"ication tank^ and also another stream o" :0E s*l"*ric acid is added into the reactor. #he reaction is carried o*t at 20 ; 0 beca*se this temperat*re %i$es maxim*m con$ersion at these conditions o" temp. 'nd press*re. 's "or as the nat*re o" reaction is concerned, itKs an Cxothermic reaction^. o the released amo*nt o" ener%y is sim*ltaneo*sly absorbed by the circ*latin% coolin% water in the /acket s*rro*ndin% the reactor. 't the end o" the reaction time when the sodi*m salicylate is con$erted into salicylic acid, its in precipitate "orm alon% with sodi*m s*l"ate. o this sol*tion is then send to the centri"*%es^ where separation is carried o*t.

DSI?+ $*0$10*%IO+S OF &*$%O&, •

4'#; >C';#!>L

•

>C=C);C #3CL  hr

•

)F34C> ! >C';#!>

•

#!#'< ;'';#U ! #C >C';#!>L &21 #!) A='U(

•

;'';#U !> C'; >C';#!>L

•

#!#'< 3' ) C> 4'#;L

&. #!)A='U(

&+.0:+67 #!)A4'#;(

• $OMPO++%S I+ FD

M*SS I+P1%

D+SI%

&?%(

&?%Am(

6.:+7

2+00

8O01M &m( )a!

.00

$hapter )


2!

++:.2

997

.+2: henol

+.+797

odi*m phen.

+.::

odi*m salicylate

+02.7

0.00++1 +219

+2+6.

0.00++: +7

0.6 2!:

72.7

+:.:

0.20

8O01M OF &*$%O& &!
%O%*0 8O01M

<  )a!H2!HhenolHsod.phenHsod.salH2!:

O:.2+1 m

DI*M%& OF %*+= $*0$10*%IO+S 'ccordin% to the consideration "or reactor diameter calc. =iameter o" tank O ei%ht o" liD*id in tank We know the "orm*la "or the $ol*me o" reactor, ol*me O &A:(R=#2Rl( &'s lO=#( #here"ore

=# O +.71 m

's the $ol*me o" reactor is not "*lly "illed and 21E is kept as $acant space,

o, #otal $ol*me o" reactor O :.2+A0.71 O 1.62: m

"O%%OM OF &*$%O& ; #he

bottom

o"

reactor

&with

re"erence

liD*id

mixin%

and

processin%^by olland and chpman( is taken as emispherical. o the total

$hapter )


$ol*me now will be contrib*ted by this part o" reactor also. #o "ind the $ol*me o" hemispherical part. We ha$e, ol*me O &2A RR r  ( 's &=# O 2Rr( o  O +.6 m

)ow the total $ol*me o" reactor #otal $ol*me O ;ylindrical H emispherical # O :.2+1 H +.6 O 1.171 m #he $ol*me o" the reactor also incl*des the $acant space pro$ided abo$e the s*r"ace. #hat is taken to be 21E o" the total, so now the $ol*me is %i$en as, 8% < @,@C@A, @ < ,76C m6

>'#!L rom literat*re considerin% len%th to diameter ratio,
 O A: R =# 2R<  O 7.:: m, =# O
< O 2.77 m

'ccordin% to the literat*re &with re"erence liD*id mixin% and processin%^(

=# O =iameter o" the tank O +.717 m =impeller O =#A O 0.176 m  O mpeller hei%ht "rom bottom O = i O 0.176 m

$hapter )


Wi O mpeller 4lade width O =i A 1 O 0.++17 m r^ O mpeller blade len%th O = i A : O 0.+::61m
O WC<A=# O ei%ht o" liD*id R &peci"ic %ra$ity( '$% A=# l O +.717)o. !" t*rbine impellers O +.

'pprox. O 2.

=istance between the impellers O +.2 R = # O 0.69: m

PO3& $*0$10*%IO+S tep +L ;'<;F<'#)5 !WC> )F34C>L

#o see the %raph yo* need to ha$e >eynoldsKs n*mber so calc*latin% )>C _ )>C O  = n2 A  ^ O +++.69 k%Am, = O dia. o" impeller, n O >..3 O +60 &*sin% #ip speed "rom lit(  O 0 cp. o )>C O +.99R+06 #hen lookin% at the %raph bAw >eynolds n*mber and power no. )> O 1 #C 82L

$*0$10*%I+? F&O1D +1M"&

$hapter )


)> O &n2 R =i A %c( n^ O re$ A sec O 2., =i O impeller dia. O +.9 "t , %c O 2.2

so we %et "rom here )> O 0.:0 ;alc*latin% exponent termL m^

m^O & a 8 lo% )>C (A b a O +, )>C O +.99R+06, b O :0 &$al*es o" a and b are "rom literat*re and %raph(

#here"ore the $al*e o" ro*d no.Ks exponent m^ is %i$en as

m < -B,)B

S%P 6; Formula for Power calculation

 O Q&) R n R =i1 ( A %cSR&)> ( m  n & re$Asec( O 2., m O -0.+06, ) > O 1,  O 69. lbA"t , )> O 0.:0 o the power calc*lated is %i$en by,

 O :.771 kw  O 6.:+ h.p

$hapter )


H*% OF &*$%IO+ I+ &*$%O& Oer all heat of reaction = &eat of for%ation of reaction ' &eat caacit chan*e

Step one;

H*% OF FO&M*%IO+ $*0$,

J Hf B
Heat of formation data is !i(en at 2@ $ o

J Hf B < 9H*% OF FO&M*%IO+ OF: L 9H*% OF FO&M*%IO+ OF: P&OD1$%S

&*$%*+%S

9 Hf : &*$%*+%S < -G,G N)B => 9 Hf : P&OD1$% < -G,@76N )B => SO4

J Hf B < 62)@B,2@ => S+SI"0 H*% $*0$10*%IO+S

 m cp J% reactants Q  m cp J% product < JH &eaction

 m cp J% reactants < -@G2C6G,BGC7 '>  m cp J% product < -7276 '>

So4 sensible heat chan!e < J H&eaction < -BC2,)262 '>

J Ho(erall < J Hf QJ H&eaction

$hapter )


J Ho(erall < -67@@22 '>

H*% %&*+SF& $OFFI$I+% $*0$10*%IO+S

S%P ); >ac'et side heat transfer coefficient %he followin! e#uation is applicable for the Eac'et side heat transfer coefficient h E < B,B26 $p N? N+ &-B,B2 N +Pr-B, N 9R A Rw:,)7 *t )),@ $B ; $pwater < 7,)CG '>A=!,= < B,GG "tuAlb, F B R water < B,GG $,P < 2,6C lbAft,hr = water < B,@GB wAm,' < B,67C "tuAhr,ft,F B water < GGG '!Am6

Mass flow rate of water; It can be calculated as4 T < m $p J % T < 9calc, throu!h ener!y balance: < 67@@22 '> < 62CB)C,G "tu So4 calculated mass of water4 m < 2)C,G6 lbs +ow as we has selected the Half pipe coil Eac'et based on dealt conditions and literature, Here we need to ha(e a Dia of pipe d), 3hich will be used in calc, Hydraulic radius4 %he standard dimension are !i(en for the half pipe coil Eac'et4 accordin! to which4 Diameter of the U pipe Eac'et < 6 )A 2 inch < B,2G2 ft

From literature4 for Half pipe coil hydraulic radius is !i(en as4D HA2

DH < 7 N )A 2 9V A 7: N9d): 2  A d) 9)2 inAft: So4

DH < B,B6C2 ft

$hapter )


+ow for &eynolds number calc, +& < W N DH N1AR O& +& <  ?NDAR 3here ? < mass (elocity ? < mass A areaN time So4 for 6 h process4 we calculate mass (elocity4 ? < )72B@C,G6 lbsAft 2,hr Hence &eynolds number can be calculated as4

+& < 22B,@@

So at the end puttin! all these (alues in the #uation of Heat transfer coefficient, hE < B,B26 N +& LB,2 N+Pr-B, N $p N ? N 9R A Rw:,)7 Hence h E < )G,2B "tuAhr,ft 2,FB

S%P 2; &*$%O& SID H*% %&*+SF& $OFFI$I+% For reactor side heat transfer coefficient we had the e#uation from the reference of literature4

+1SS*0% +O, < hi D% A = < B,7 N +& B, N +PrB,66 N 9R A Rw:, )7

$hapter )


*s4 +& < )C@@2B, +Pr < $p N R A = FB

$pmix < B,7@7 "tuAlb, R mix < )),@) lbAft,hr = a(!,

B

"tuAhr,ft,F

<

B,B@

%herefore4

hi < ,@G "tuAhr,ft 2,FB

S%P 6; O8&*00 H*% %&*+SF& $OFFI$I+% For o(erall heat transfer e#uation we had the e#uation, ) A 1 < ) A hi Q ) A h E Q . A = 1 < o(erall heat transfer coefficient ac'et side film coefficient < )G,2B "tuAhr,ft 2,FB . < %hic'ness of (essel wall
1 < 7,)6 "tuAhr,ft 2,FB < 2C,2C 3Am2,'

%IM $*0$10*%IO+ FO& ISO%H&M*0 $OO0I+? MDI1M

lo!e  9%b) L %c: A 9%b2 L %c :  <1i *i A 3 $p  N Jt

3here as4 Jt < %ime ta'en to cool the a!itated li#uid, 9hr:
>*$=%D

$hapter )


%b)< nterin! %emp, for li#uid in 8essel, 9F B: < )7@ FB %b2< 0ea(in! %emp, for li#uid in 8essel, 9F B: < C FB %c < %emperature of coolin! medium, 9F B:*(!,< @2, FB 1i < O(erall heat transfer coefficient,9"tuAhr,ft 2,FB: < 7,)6 "tuAhr,ft 2,FB *i < *rea ft2K *rea < V N D% N Hl

* < 6,)7 N @,G N @,C < )B), ft 2 So the time can be calculated for coolin! the mass4 by puttin! all abo(e (alues in e#uation,

Jt < 2,)@ hr

SPECIFICATION SHEET

ID+%IFI$*%IO+; Item; Item number; +o, &e#uired;

F1+$%IO+;

*cidification reactor *,&,6 B6

$hapter )


Formation of product4 salicylic acid from reaction of sulfuric acid with sodium salicylate,

OP&*%IO+;

4atch operation %P OF &*$%O&;

@acketed a%itated cylindrical $essel DSI?+ D*%* 8SS0;

!
7.:: m

%MP&*%1& P&SS1& DI*M%& OF 8SS0 HI?H% HI?H% %O DI*, &*%IO 8O01M OF "O%%OM +O, OF "*FF0S

2B $ B ) atm, ),@ m 2, m ),@ ),6 m 6 B7

'5#'#!>L '5#'#!> ='.

0.176 m

HI?H% F&OM "O%%OM 3ID%H OF %1&"I+ "0*D SPD OF *?I%*%O& PO3& &T1I&D

B,@C m B,))@ m )7B rpm 7,@ 'w

@';?C#L

C'# #! 4C >C3!C= H*% %&*+SF& *&* H*% %&*+SF& $OFFI$I+% h >, O8&*00 H*% %&*+SF& $OFFI$I+% 1 D 3*%& I+0% %MP,

:1122 k/ G,77 m 2 )))C,@2 wAm2,' 2C, wAm2,' 7 $B

$hapter )


3*%& O1%0% %MP&*%1&

)G $ B

M*%&I*0 OF $O+S%&1$%IO+; ?0*SS 0I+D MI0D S%0

S$L/'S S,S0NS/$N aintainin) soids in suspension it%in a iuid is anot%er !er* common appication "or "uid a)itation euipment. /ndustria eampes are di!erse as suspendin) ore in c*anide eac% s*stems or diatomaceous eart% in a "iter aide

$hapter )


surr*. T%e nature o" t%e soids t%e concentration o" soids and t%e de)ree o" suspension desired a contri+ute to a)itator desi)n. /n order "or soids to +e suspended t%e impeer must create enou)% ocai&ed "o to o!er come t%e settin) !eocit* o" t%e materia to +e suspended. Hi)% e""icienc* aia "o impeers 6HF218 and t%e "o pattern t%e* produce are +est suited "or suspendin) soids. T%e de)ree o" suspension is t*pica* +ro(en don into t%ree di""erent cate)ories in order o" increasin) di""icut*.

On-Bottom Motion— a partices mo!in) on t%e +ottom it% t%e i)%ter ones suspended o"" t%e +ottom.

Off-Bottom Suspension—a partices suspended o"" t%e +ottom +ut not uni"orm*.

Complete Uniformity— a partices suspended uni"orm* t%rou)%out t%e tan(. T%e process !aria+es t%at can +e controed in t%is cate)or* incude dissoution rate "or sou+e soids *ieds 6cr*stai&ers8 and mass trans"er.

$hapter )


DSI?+ OF $+%&IF1? ),

$alculations of 8olume of $entrifu!e ol*me o" centri"*%e

2,

6,

⇒

1 &+.22( O +.121 m :

O

$alculations of Diameter X hei!ht π

=2 X 



O

A=

O

=

O

⇒

=

O

+.:6 m





O

0.9+21 m

O

0.7 m

:

0.621 +.121 × : ,.+: × 0.621

%hic'ness of $a'e >

O

+.:6 2

msolid

O

+0:+.67 H 116.:7 O +19.+:

ρsolid

O

2019. k%Am

solid

O

solid

O

π X  &> 2 8 >;2(

0.7

O

.+: X 0.9+21 &0.72 8 >;2(

0.7

O

+.1 8 2.6 >;2

>;

O

+.1, − 0.72.-6

O #hickness o" cake

+19-.+: 2019.,

O 0.7 m

0.12 m O

> 8 >;

$hapter )

7,

@,


0.7 8 0.12

O

0.2+ m

O

2+ cm

$alculation of Inner &adius of Slurry 9I&S: ol*me o" sl*rry

O

>

O

π X  &> 2 8 >2( &,.+: × 0.9+21 × 0.7, 2 ( − +.22 ,.+: × 0.9+21

O

0. m

O

 cm

&elati(e $entrifu!al Force 9&$F: >;

,

O

O

0.000+:2 n2=

O

0.000+:2 &+000(2 X :.79

O

60.+ %

$entrifu!al Pressure c

O

+ 2

ρ ω2 &> 2 − >2 (

O + 2

+2.9,.1 × &+0:.67( 2 &0.7, 2

,

− 0.,, 2 ( O

.00: X +06 ).m2

O

>A &c H ρm > ω2(

3all %hic'ness "

+.:+ X +0  O 6 2 &.00:X+0 H07.6X1X0.7X+0:.67 (

0.7

2.:+ X +0 

O

2.+9 X +06 H 0.6: X +0 s

&2.:+ 8 0.6:(+0 

O

2.+9 X +06

$hapter )




C,

O

2.+9 × +0 +.77 × +0

6

-

O

0.+27 X +0- m

O

+2.7 mm

O

+ mm

Self and total Stresses 

#

'llowable stresses are &#  "(

O

ω2 > 2 ρm

O

&+0:.67(2 &0.7(2 &07.6(

O

:.69 X +07 )Am2

O

2 X :.69 X +07 )Am2

O

2 X :.69 X +07 )Am2

O

9. X +07 )Am2

O

2.:+ X +0 )Am2

O

&@*sti"ied(

O

G,

+o, of Holes in 3all of "as'et =iameter o" hole

O

1 mm O 0.+961^

'rea "or one hole

O

&0.77:(2

O

0.000: m2

O

π=

O

.+: X +.:6 X 0.9+21

O

:.+ m2

#otal 'rea a$ailable

)o. o" holes

O

)o. o" holesAm2

O

:.+0.000:

2100

O +0:10 holes

$hapter @

)B,

Desi!n of #uipments

Power $alculations 3oment o" inertia o" "eed Where

o,

O

m+

 O

2

&>

2

+

2

> + (

>

O

>adi*s o" 4asket

> +

O

> 8 e &e is thickness o" liD*id(

> +

O

0.7 8 0.++1 &0.7(

O

0.6: m



O O

+172.-9 2

&0.7, 2

− 0.6: 2 (

96.97 k%.m2

3oment o" inertia o" basket O

 b O m2 > 2

Where

m2

O

3ass o" 4asket

m2

O

π =   ρm

O

.+: X +.:6 X 0.9+21 X 0.0+27 X

O

:+1.9 k%

 b

O

:+1.9 X 0.72 O 22+.6



O

 H  b O 96.97 H 22+.6

O

+.6 ?% m2

O



O

+.6 X

O

τ X ω

O

+++.+6 X +0:.67

O

++61.+2 Watts

O

++.6 ?w

O

+1.19 ..

07.6

τ

p

dω dt +0:.67 1 × 60

O +++.+6 )-m

$hapter @


O

+6. ..



SP$IFI$*%IO+ SH% +.

CD*ipment

;entri"*%e

2.

#ype

#op s*spended basket

.

3ethod o" operation

4atch wise

:.

)o. >eD*ired

#hree

1.

*nction

#o separate alicylic 'cid crystals "rom mother liD*or.

6.

4asket =iameter

+.:6 m

7.

peed

+000 rpm

.

3axim*m centri"*%al "orce

60.+ %.

9.

#ypical motor sie

+6 ..

+0.

3aterial o" constr*ction o" basket

tainless steel +6

++.

)o. o" holes per sD.meter

2100

$hapter @


Desi!n of dryer D&I+? OP&*%IO+ =ryin% o" solids means the remo$al o" relati$ely small amo*nts o" water or other liD*id "rom the solid material to red*ce the content o" resid*al liD*id to an acceptably low $al*e. =ryin% is *s*ally the "inal step in a series o" operation and the prod*ct "rom a dryer d ryer is o"ten ready "or "inal packa%in%.

$lassification of Dryer %ypes ' wide $ariety o" dryers are *sed in the process ind*stries. owe$er "ollowin% criteria is employed to classi"y dryersL ),

Method of Operation

#able 1.7.+ classi"ies dryer by method o" operation. #he "irst s*bdi$ision is by method o" heat trans"er.

  

a(

;ond*ction he heatin%

b(

;on$ection heatin%

c(

n"r n"raa-re red d hea heati tin% n%,, i.e i.e.. all all "orm "ormss o" o" rad radia iati tion on hea heati tin% n%

d(

=ielectric heatin%

=istinction sometimes bl*rred

reee dryin% may be classi"ied as a special case o" cond*ction heatin%. #he next main s*b-di$ision is by type o" dryin% $essel 8 tray, rotatin% dr*m, "l*idied bed, pne*matic, spray. #he table also shows which types o" $essel are more readily adapted to operation *nder $ac**m or with inert atmospheres. i%. 1.7.+ shows dia%rams o" most o" these types o" dryer.

$hapter @


%able %able ,); $lassification of Dryers based on Method of Operation

2,

Physical Form of Feed

t m*st "irst be emphasied that p*rely mechanical means sho*ld be *sed to red*ce the moist*re content o" the wet "eed to as low a "i%*re as possible, beca*se with "ew exceptions, processes s*ch as e$aporation, "iltration and centri"*%in% are cheaper and "aster than eD*i$alent processes in dryin% plant. #able 1.7.2 classi"ies types o" dryer in terms o" the physical "orm o" the material to be "ed to the plant. >aw pastes and sl*d%es are di""ic*lt to handle into dryers and the dryin% rate D*ickly slows down thro*%h the "ormation o" s*per"icial skins ha$in% a low permeability to $apo*r. #his "orm o" "eed there"ore reD*ires pretreatment by pre"ormin%K into pellets abo*t 1 mm c*be or by "ormin% %ran*les with mixed back "ines.

$hapter @


%able %able @,,2 $lassification of dryers based on physical form of feed

6,

Scale of Operation

#able 1.7. shows the types o" a$ailable dryer classi"ied accordin% to scale o" prod*ction. prod*ction. t will be seen that the n*mber o" types "or contin*o*s contin*o*s lar%e scale dryin% is m*ch more limited than "or medi*m scale o*tp*ts.

$hapter @


%able @,,6 $lassification of dryers by scale of production

7,

+ature of the Feed

We then come to classi"ication in terms o" o$erridin% "eat*res s*ch as toxic or heat sensiti$e materials, special "orm o" dry prod*ct etc.B these are shown in #able 1.7.:. %able @,,7 $lassification of dryers by suitability for special features

@,

$apital and Operatin! $osts

=ryers may also be classi"ied in terms o" the labo*r, heat, "lexibility and capital cost o" their operation. 3echanical maintenance cost can only be estimated by st*dy o" the desi%ns pro$ided by indi$id*al man*"act*rers.

$hapter @

,2


S0$%IO+ OF D&&

When selectin% a dryer, there are se$eral D*estions that need to be answered "or all types o" dryers. >otary dryers will be *sed to ill*strate problems beca*se they dry more material than any other dryer. ' "ew o" the problems are as "ollows. ),

%ype of Feed

What type o" dryers can handle the "eed_ " the "eed is liD*id, dryers s*ch as spray, dr*m, or one o" the many special dryers that can be adapted to liD*ids may be *sed. " the "eed is D*ite sticky, it may be necessary to recycle m*ch o" the prod*ct in order to *se a certain type o" dryer. #he best sol*tion to the "eed problem is to try the material in a pilot *nit. #he pilot *nit "or a spray dryer needs to be near the sie o" the prod*ction *nit as scale-*p is D*ite di""ic*lt in this case. 2,

&eliability of Dryer

s the dryer reliable_ s the dryer likely to ca*se sh*tdowns o" the plant, and what per"ormance history does this *nit ha$e in other installations_ ow lon% is the a$era%e li"e o" this type o" dryer_ 6,

ner!y fficiency

ow ener%y-e""icient is this type o" dryer_ or example, a steam t*be dryer may ha$e an e""iciency o" 1E while a plain t*be type o" rotary dryer may ha$e an e""iciency o" only 10E. owe$er, prod*ction o" the steam entails additional costs so the plain t*be may be more e""icient in o$erall prod*ction.

$hapter @


#he hi%her the temperat*re o" inlet %as stream, the hi%her the e""iciency o" the dryer in %eneral. ' "l*id-bed dryer has a hi%h back-mix o" %as so it is possible to *se a "airly hi%h enterin% %as temperat*re. 'ny dryer can *se recycled stack %as to lower the inlet %as temperat*re and th*s obtain a hi%h e""iciency "or the dryer. owe$er, i" there is any or%anic material in the stack %as, it may be cracked to "orm a $ery "ine carbonaceo*s partic*late which is almost impossible to remo$e "rom the stack. >ecycle also increases the dew point o" the incomin% %as which lowers the dryin% potential o" the dryer. #his lowerin% o" the potential is D*ite important when dryin% heatsensiti$e material. &#= has to ha$e a low $al*e.( 7,

Heatin! Fuel

What type o" "*el can be *sed "or heatin%_ =irect heatin% is *s*ally the most e""icient *nit, and nat*ral %as and <..5. are the best "*els. owe$er, both %ases are %ettin% more expensi$e and in many cases will not be a$ailable. #he next best "*el is li%ht "*el oil which can be b*rned readily with a clean^ stack. #his material is expensi$e, and in some cases may be in short s*pply. #he third best "*el is hea$y "*el oil which is *s*ally a$ailable, b*t this oil reD*ires special b*rners and may not %i$e a s*""iciently clean stack. ;oal is d*sty and hard to handle. #he stack %as *s*ally is too contaminated "or *se in most installations. @,

Dust Problem

=oes the dryer ha$e a d*st problem_ team t*be *nits *se $ery low air "low and ha$e minor d*st problems, while a plain t*be *ses hi%h air rates and may ha$e serio*s d*st problems. n some cases the stack d*st remo$al de$ices may cost more than the dryer. ,

Sensiti(ity of Material

ow heat sensiti$e is the material to be dried_ 3ost materials ha$e a maxim*m temperat*re that can be *sed witho*t the prod*ct deterioratin%. #his temperat*re is a "*nction o" the time o" expos*re as the thermal deterioration

$hapter @


*s*ally is a rate phenomena. Wet material can stand m*ch hi%her temperat*res in the %as d*e to the e$aporation coolin%. 's an exampleL ' rotary dryer workin% with al"al"a can *se +:00o enterin% %as in a co-c*rrent *nit. ' co*nterc*rrent *nit at this temperat*re wo*ld b*rn the al"al"a. 's the temperat*re o" the enterin% %as determines the e""iciency o" the dryer, co-c*rrent dryers, on the a$era%e, are more e""icient than co*nterc*rrent dryers. ,

Tuality of Product

What D*ality o" prod*ct will be obtained "rom the dryer_ reee dryin% *s*ally will %i$e an excellent prod*ct, b*t the cost is prohibiti$e in most cases. ' dryer needs to balance D*ality a%ainst cost o" prod*ction o" a satis"actory prod*ct. C,

Space 0imitations

What space limitations are placed on the installation_ #here are certain hei%ht limitations in some b*ildin%s, and "loor space may be limited or costly. G,

Maintenance $osts

3aintenance costs are o"ten a ma/or consideration. " mo$in% parts either wear o*t or break down d*e to material ballin%-*p^ or stickin%, the plant may be sh*t down "or repair, and repairs cost money. " this is a problem, a record sho*ld be kept o" the per"ormance o" the *nit. t may be possible to %et this in"ormation "rom a plant which is *sin% this partic*lar *nit on a similar prod*ct. )B,

0abour $ost

What is the labor cost_ ' tray dryer has hi%h labor costs, b*t it is the best dryer in many cases where only small amo*nts o" material need to be handled. )),

*(ailability of Data

s a pilot *nit a$ailable which can be *sed to %et data to desi%n the needed prod*ction "acility_ )early all new prod*cts need pilot plant data "or a satis"actory desi%n o" a dryer. n the case o" spray dryin%, an ind*strial sie *nit needs to be *sed. =r*m and rotary *nits and most other dryers can be scaled-*p with s*""icient s*ccess "rom laboratory sied *nits.

$hapter @

)2,


$apital In(estment +eeded for *ccessories

What is the capital in$estment "or the dryer and all the accessories_ )6,

Power &e#uirement

What is the power reD*irement "or the dryer_ ' deep "l*id-bed dryer needs hot %as at a hi%her press*re than most other dryersL +000 "t Amin o" %as reD*ires approximately + hp per : in. o" water press*re. )7,

Scale of Production

What D*antity o" prod*ct is desired_ or lar%er prod*ction a spray or rotary dryer sho*ld be considered. >otary and spray dryers handle most lar%e prod*ction demands, b*t in small prod*ction plants other dryers are o"ten more economical. )@,

&an!eability

;an the dryer per"orm o$er a wide ran%e o" prod*ction rates and still %i$e a satis"actory prod*ct in an e""icient manner_ !nce the abo$e points ha$e been examined, it is possible to select a "ew types o" dryers that appear to be the best "or the partic*lar operation. ilot plant data sho*ld be obtained on these dryers to determine the sie needed. irm D*otations sho*ld be obtained "rom the man*"act*rers. #he most economical dryer now can be selected on the basis o" D*ality o" prod*ct and capital and operatin% costs.

$hapter @

@,,6


3H %O S0$% HO&I/O+%*0 &O%*& 8*$11M D&& #here are "ollowin% reasons in order to select horiontal rotary $ac**m

dryer "or o*r process. +.

4eca*se the material comin% "rom centri"*%e is sticky, so in order to make an e""ecti$e heat trans"er, s*r"ace renewal is needed. 4eca*se materials stick to the s*r"ace o" dryer so an a%itator is reD*ired "or s*r"ace renewal and to make an e""ecti$e heat trans"er.

2.

alicylic acid has tendency to disinte%rate into benoic acid and phenol at its boilin% point, there"ore $ac**m is employed in order to lower the boilin% point o" water.

Dryin! Operation #he centri"*%alie *ndried prod*ct salicylic acid is wei%hed, then by means o" the hoist, li"ted to the hopper o" the cylindrical $ac**m drier, at the same time. #he stirrer inside the drier is started *p. '"ter loadin%, 0.: 3a  +:1o; steam is *sed in the /acket "or heatin%. #he $ac**m p*mp is started *p, the system is at $ac**m state, $ac*ity ≥0.0 3a, the material temperat*re sho*ld not exceed 70o; d*rin% the dryin% process. #he dryin% time is *s*ally  G : ho*rs. '"ter dryin% samples are taken and analyed. When the moist*re is ≤0.1E, the prod*ct will be D*ali"ied and ready "or dischar%e. #he obtained prod*ct is coarse salicylic acid, wei%hed, then transported to the s*blimation re"inement. #he power d*st o" salicylic acid prod*ced d*rin% dryin% process will be ret*rned to the cylindrical $ac**m dryer by the spiral con$eyorB small amo*nt o" powder d*st will be drawn into the phenol water recei$er thro*%h the water tank,

$hapter @


and then p*shed *nder press*re into the centri"*%e "or reco$ery o" ' &alicylic acid(. #he condensed water prod*ced in the dryin% process, "lows by %ra$ity thro*%h the condenser to the phenol water recei$er, "rom where it is p*shed by press*re into the centri"*%e, the phenol water "lows into the o$er"low pool, then into the sewa%e pool "or reco$ery o" phenol by extraction.

@,,7

DSI?+

OF

HO&I/O+%*0

8*$11M

&O%*&

D&& @,,7,) Data for $alculation of Horizontal 8acuum &otary Dryer 'mo*nt o" "eed

O

ms O :1660 k%Aday

3oist*re content in "eed

O

V+ O +6E &70 k%Aday(

eed temperat*re, ti

O

29o?

3oist*re content in prod*ct

O

V2 O 0.+9E &72.9 k%Aday(

rod*ct temperat*re, to

O

:o?

olids speci"ic heat, ;s

O

;s

O

[0.266 &+60.9(].'. H [0.+76 &+7.29(])a2!: O

6+.7: ?@Ak% mol o?

Water speci"ic heat

O

71 ?@Ak% mol o?

eatin% medi*m

O

team

team temperat*re, #

O

:+ o? at 0.: 3a

Cnthalpy o" steam

O

279 ?@Ak%

@,,7,2 %hermal Data for Moisture and solids C$aporation enthalpy Water enthalpy at +1 ?a &$ac**m(

at

O

270 ?@Ak%

O

&27o?( &4.pt.( 221.622 ?@Ak%

1:o;

$hapter @


Water '$era%e &1:o; 8 +:1o;( &27o? 8 :+o?(

$apor O

2669.7

O

27o?

start O

o"

olids temp. in constant rate d*rin% period rod*ct 3oist*re rate period, Vc

at

+ eatin%

"allin%-

E

2

,

;ons tan t − rate

6allin% − rate =ryin%

=ryin% eat ?@ 2

trans"er

rate, +0+

enthalpy, ?@Ak%

11

00

0

60

o

hr .m .?

*r"ace loadin%, E

+00

$alculation =ry solids

rod*ct, m s m sd &+ − V 2 (

m s d O ms &+ 8 V+(

O

:1660 &+ 8 0.+6(

O

1:.: k%Aday

O

p

=

O

,-,1:.: &+ − 0.00+9(

3oist*re "allin%-rate

=

,-:21 k% A day

at O

3oist*re in "inal prod*ct O

m sd

chan%e to × V c ,-,1:.: × 0.0-

&+− V c (

=

&+ − 0.0-(

1 k%

O

:21 x 0.00+9

O

7 k%Aday

O

ms 8 msp

O

:1660 8 :21

O

721 k%Aday

(aporation #otal e$aporation

$hapter @


C$aporation *pto "allin%-rate

O

1 8 7

Ione

O

262 k%Aday

C$aporation *pto constant-rate

O

721 8 262

Ione

O

97 k%Aday

$hapter @


Ione !peration

+

2



eatin%

;onstant-rate dryin%

allin%-rate dryin%

%emperature4 o=

team temp. o?

:+

:+

:+

:+

:+

olids temp. o?

29

27

27

27

:

+21

9+

9+

9+

71

$ %

&$ − t o ( − &$ − t i (

=

ln[&$ − t o ( A &$ − t i (]

+07.+02

9+

2.7:

#emp.di"" &o?(

Heat 0oads4 =>Ahr

olid heat load &?@Ahr(

=ay

k%-mol

;p &eat ;apacity( in ?@

2: hr

=ay

?% mol o?

=

27: .-- x &,27

− 29,(

=

2:

O 2:,0:2 ?@Ahr
= :06x &,27

heat

load

Ione totals o" heat load &?@Ahr(, Th, Tc, Tt

− 29,( x :.

= :.1&,:,

2:

*r"ace area, m2 &ad/*sted "or loadin%(

O

Th #m h . h h . < n

− ,27( x :.+ 2:

O +2.17 ?@Ahr

=

26,:1

2:

O ++,+: ?@Ahr

O 2:+0.12 ?@Ahr C$aporation &?@Ahr(

27:.--x &,:, − ,27 (

,97,x 2,7 2:

=

,262& 2609.7- − 221. 2:

O92,: ?@Ahr

O 2,202 ?@Ahr

O 92,:

O :,12

O

Tc #mc . h c .
O

T" #m " . h " . <"

$hapter @


O

26:1, +07.+02 × +0+ × +.0

O 2.:: m2

O

,92,,: 9+ × 1-1 × 0. O 9.2+ m2

O

,:,12-2.7: × ,00 × 0.6

O 2.07 m2

$hapter @


#otal heat s*r"ace reD*ired, m2, '

O

:.72 m2

#otal heat load, ?@Ahr, T#

O

762,+6 ?@Ahr

team "low-rate

O

T#

O



O

762,+6 27,9

27.2 k%Ahr

rom #able o" sies \\. ac**m rotary dryer

or heatin% s*r"ace o" :.72 m2, #otal capacity o" dryer, 
m

O

+:.06 m

O

6

O

π

: π

O =2<

&=2( &6=(

+:.06

O

2.979

O

=

=

O

+.:: m

<

O

6= O 6 X +.:: O .6

:

$hapter @


 $ >ate o" dryin%, m

h y &# − #i ( + '

O

λi

 $ m

O

>ate o" dryin% &k%Ahr(

#

O

temperat*re o" steam

#i

O

#emperat*re at inter"ace

'

O

=ryin% area

λi

O

hy

O

eat trans"er co-e""icient, [email protected]?

 $ m

O

 $ m

O

t#

O

t#

1-1 & :+- − ,-,( × ,:.7 2229.9:

+.6+ k%Ahr ms

$ m

 ( V+ − V c ) + V c 

 V c      V  2  

ln 

O

 ( 0.+6 − 0.0-) + 0.0,+-.6+ 

O

.6+ hr

72,1

 0.0-     0.00+9  

ln 

or total dryin% time the  o" batches are calc*lated asL )o. o" batches

O

2: t#

O 2: -.6+

= 2.79 ≈ , batches

DSI?+ OF S%*M >*$=% rom errysK ;hemical Cn%ineersK andbook or steam in 'nn*l*sL 3

o

3

'

$hapter @


= =o

O

0.66: +.:: m &calc*lated(

's

=i

O

o,

=o

O

=o

O

+.:: 0.66:

2.+7 m

ence 'nn*l*s dia "or steam "low

=a 'rea o" ann*l*s

O

=o 8 =i

O

2.+7 8 +.::

O

0.7 m

O

O O

π :

π :

&= a ( <

&0.7,( × -.6,

:.91 m2

$hapter @


S1"0IM*%IO+

*blimation is a process in which a solid is $aporied witho*t %oin% into liD*id state and then are condensed back into solid state.^

Where asL

Tuasi-sublimation ; n this process a molten solid is $aporied and then condensed directly back to solid state.

)ormally a s*bstance processed by s*blimation, is a solid at or near ambient temperat*re and press*re and has a reasonably hi%h $apors press*re at operatin% temperat*res, typically a minim*m o" 1 m.% absol*te.

&e(iews of industrial applications of sublimation techni#ues ha(e been made by; =emp 9)G@C:Y Holden and "ryant 9)GG:Y Mellor 9)GC:Y =udela and Sampson 9)GC:Y

*blimation is *sed to separate $olatile solids and to p*ri"y the s*bstances. !ne sho*ld consider *sin% s*blimation when per"ormin% the "ollowin% stepsL

•

>emo$in% the $olatile prod*ct "rom a non-$olatile material or mixt*re o" materials or remo$in% the $olatile materials "rom a non-$olatile prod*ct.

•

eparatin% more $olatile "rom less $olatile components in a mixt*re o" $olatile materials.

•

eparatin% a prod*ct "rom its imp*rities when either is *nstable or heat sensiti$e at temperat*res close to the meltin% point.

$hapter @


•

reparin% a reD*ired type or sie o" crystalline prod*ct.

•

*ri"yin% a wet "eedstock in which dryin% and p*ri"ication can take place in a sin%le s*blimation step.

ome commercial s*blimation processes are %i$en in "ollowin% tableL

#'4C#U ! F4#');C ;') 4C F4<3C=

•

'=C

•

3!!V=C

•

')#>';)C

•

)'#
•

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$hapter @


P&I+$IP0S OF OP&*%IO+; #he basic principles o" $aporiation and condensation ha$e been disc*ssed by >*nter^, 5old"in%er^, and irth^, in +96:. 4y trickland-constable^ in +96 also by 3ellor^ in +97.

#he mechanism o" a s*blimation process can be described with re"erence to the ress*re #emperat*re phase dia%ram in the %i$en "i%*re. #he si%ni"icance o" the -# dia%ram applied to one component system. #he phase dia%ram is di$ided into three re%ions, olid,
#he position o" the triple point in the dia%ram is o" *tmost importance

•

" it occ*rs at a press*re abo$e atmospheric, the solid cannot melt *nder normal atmospheric conditions, and process is called as %rue Sublimation ^ L& =irect "rom solid to $apo*r(.

•

" it occ*rs at a press*re less than atmospheric, howe$er, certain preca*tion are necessary, #he phase chan%es olid to $apor^ or $apor to solid^ m*st be controlled, beca*se it may in$ol$e the liD*id state^.

n ind*strial applications it is not *ncommon "or liD*i"ication to be allowed in $aporiation sta%e^, to "acilitate better heat trans"er, b*t this m*st

$hapter @


ne$er be allowed in the =es*blimation or ;rystalliation step^. #he condensation eD*ipment there"ore m*st operate well below the triple point. " liD*i"ication is employed be"ore $aporiation,

the operation is o"ten called Pseudo-

Sublimation ^.

4oth tr*e and se*do-s*blimation are depicted in the "i%. or the case o" a s*bstance with a triple point at a press*re %reater than atmospheric,  %&1 S1"0IM*%IO+ ^ occ*rs. #he complete cycle is %i$en by the path '4;=C^,

the ori%inal solid ' is heated to some temperat*re represented by 4. #he increase in the $apor press*re press*re o" the s*bstance is traced alon% the s*blimation c*r$e "rom ' to 4. #he condensation side o" the process is represented by the broken line 4;=C^. 's the $apor passes o*t o" the $aporier into the condenser, it may cool sli%htly and it may become dil*ted as it mixes with some inert %as s*ch as air. oint ;, there"ore representin% a temperat*re and partial press*re sli%htly lowers than point 4.

#he condensation side o" the process is represented by the broken line 4;=C^. 's the $apors pass o*t o" the $aporier into the condenser, it may cool sli%htly, and it may become dil*ted as it mixes with some inert %as s*ch as 'ir. !)# ;, there"ore representin% a temperat*re and partial press*re sli%htly lower than point 4, can be taken as condition at the inlet to the condenser. '"ter enterin% the condenser the $apor mixes with more inert %as and partial press*re o" the s*bstance and temperat*re will drop to some point =. #herea"ter the $apor cools essentially at a constant press*re to the conditions represented by point C, the temperat*re o" the condenser. When the #riple point o" the s*bstance occ*rs at a press*re less than atmospheric, the heatin% o" the solid may easily res*lt in its temperat*re and $apor press*re exceedin% the #riple point conditions. #he solid will then melt in

$hapter @


the $aporier thro*%h path ' to 4K in the "i%. represents s*ch a process. ow e$er %reat care m*st be taken in the condensation sta%e. #he partial press*re o" the s*bstance in the $apor stream enterin% the condenser m*st be red*ced below the #riple point press*re to pre$ent initial condensation to a liD*id. #he reD*ired partial press*re red*ction can be bro*%ht abo*t by dil*tin% the $apors with an inert %as, b*t the "ractional press*re drop in the $apor lines is %enerally s*""icient in itsel". oint ; represents the conditions at the point o" entry into the condenser and the condensation path is represented by ;K=C.

P&O$SS *+D T1IPM+%;

!n commercial scale, it is di""ic*lt to $aporie and condense a solid as well as to control these steps. eat trans"er is typically low and remo$in% condensed solids "rom a s*r"ace is not possible. ' proposed s*blimation process can become commercial i" economical sol*tions to s*ch problems can be "o*nd.

Sublimation techni#ues can be classified con(eniently into three basic types;



SIMP0 S1"0IM*%IO+



8*$11M S1"0IM*%IO+



+%&*I+& S1"0IM*%IO+

$hapter @


SIMP0 S1"0IM*%IO+; n this type o" s*blimation the solid material is heated and $aporied, and then $apor di""*ses to condenser. #he dri$in% "orce "or di""*sion is the partial press*re di""erence^ between the $aporiin% and condensin% s*r"aces. #he $apor path between the $aporier and the condenser sho*ld be as short as possible to red*ce the resistance to "low. imple s*blimation has been practiced "or the, 'mmoni*m chloride, iodine and "or the "lowers o" s*l"*r also.

8*$11M S1"0IM*%IO+; tKs a nat*ral "ollow on "rom simple s*blimation. #he trans"er o" apor "rom $aporier to the condenser is enhanced by red*cin% the press*re in the condenser, which th*s increases the partial press*re dri$in% "orce. odine, pyro%ellol and many metals ha$e been p*ri"ied by this type o" s*blimation. #he exit %ases "rom the condenser *s*ally pass thro*%h a cyclone or a scr*bber to protect the $ac**m-raisin% eD*ipment and to minimie the loss o" prod*ct.

+%&*I+& S1"0IM*%IO+; n this type o" s*blimation an inert %as is blown into the $aporiation chamber o" a s*blimer to increase the rate o" "low o" $apors to the condensin% eD*ipment and th*s increase the yield. *ch a process is known as +%&*I+& S1"0IM*%IO+,

#he *se o" entrainer in process has many desirable "eat*resL



It enhances the (apor flow from sublimer to the condenser



It also pro(ides the heat needed for sublimation



Pro(idin! an efficient mean to control the temperature

$hapter @




Pro(idin! enou!h contact time to saturate air with (apor

#he p*ri"ication o" alicylic acid pro$ides a %ood application o" the *se ind*strially o" entrainer s*blimation. 'ir may be *sed as the carrier %asL 4*t as salicylic acid can be decarboxylated in hot air, a mixt*re o" air and carbon dioxide is o"ten pre"erred. ' 1 to +0E o" carbon dioxide is recycled thro*%h the plant, passin% o$er heater coils be"ore o$er the containers, e.%. 4in or trays, holdin% the imp*re salicylic acid in the $aporier. #he $apors are then passed thro*%h the series o" air cooled chambers, where s*blimed salicylic acid is deposited. ' trap remo$es any entrained s*blimate be"ore the %as stream is ret*rned to the heaters. 3ake *p ;!2 and air are introd*ced into the system as reD*ired, and the process contin*es *ntil the containers are emptied o" all $olatile matter. #he imp*re material is p*l$eried in a mill, and hot air or any s*itable %as mixt*re blows the "ine particles, which readily $olatilie, into a series o" separator, e.%. cyclones, where non-$olatile solid imp*rities are remo$edL ' "ilter may also be "itted in the $apor lines to remo$e "inal traces o" imp*rities. #he $apors are then passed to the series o" condensers. #he %ases can be recycled or passed to atmosphere thro*%h a cyclone or scr*bber.

#o obtain the max yield o" the prod*ct the air sho*ld be sat*rated with the $apors o" salicylic acid at +10 0; and sat*ration will only be approached i" the air and salicylic acid are contacted "or a s*""icient period o" time at the reD*ired temperat*re. ' "l*idied bed $aporier may allows these optim*m conditions to be approachedB b*t i" air is simply blown o$er bins or trays is containin% the solid, sat*ration will not be achie$ed and the act*al rate o" s*blimation will be less than that calc*lated. n some cases the de%ree o" sat*ration may be as low as +0 E o" the possible $al*e.

$hapter @


#he calc*lated loss o" prod*ct in the condenser exit %ases is only a minim*m $al*e. 'ny other losses d*e to solids entrainment will depend on the desi%n o" the condenser and cannot be calc*lated theoretically. 'n e""icient exit %as scr*bber can, o" co*rse, minimie these losses.

$hapter @


$hapter +o, 

Instrumentation and Process $ontrol

$hapter @


$hapter  Instrumentation and Process $ontrol 3eas*rement is a "*ndamental reD*isite to process control. Cither the control can be a""ected a*tomatically, semi a*tomatically or man*ally. #he D*ality o" control obtainable also bears a relationship to acc*racy, re prod*ct ability and reliability o" meas*rement methods, which are employed. #here "ore , selection o" the most a""ect means o" meas*rements is an important "irst step in desi%n and "orm*lation o" any process control system.

Temperature measurement and control #emperat*re meas*rement is *sed to control the temperat*re o" o*tlet and inlet streams in heat exchan%ers, reactors, etc. 3ost temperat*re meas*rements in the ind*stry are made by means o" thermoco*ple to "acilitate brin%in% the meas*rements to centralied location. or local meas*rements at the eD*ipment bimetallic or "illed system thermometers are *sed to a lesser extent. *s*ally, "or hi%h meas*rement acc*racy, resistance thermometers are *sed. all these meas*rements are installed with thermo wells when *sed locally. #his pro$ides protection a%ainst atmosphere and other physical elements.

Pressure measurement and control
$hapter @


#h*s press*re meas*rement becomes an indication o" an ener%y decrease or increase. 3ost press*re in ind*stry are elastic element de$ices, either directly connected "or local *se or transmission type to centralied location. 3ost extensi$ely *sed ind*strial press*re is the 4o*rderi #*be or a =iaphram or 4ellow %a*%es.

Flow measurement and control low indicator are *sed to control the amo*nt o" liD*id. 'lso all man*ally set streams reD*ire some "low indication or some easy means "or occasional sample meas*rement. or acco*ntin% p*rposes, "eed and prod*ct streams or metered. n addition *tilities to indi$id*al and %ro*ped eD*ipment are also metered. 3ost "low meas*res in the ind*stry areA by ariable ead de$ices. #o a lesser extent $ariable area is *sed as are many types a$ailable as special meterin% sit*ation arise.

$ontrol scheme of distiallation column

General consideration Obecti!es n distillation col*mn any o" "ollowin% may be the %oals to achie$e. +. !$erhead composition 2. bottom composition . ;onstant o$er head prod*ct rate. :. ;onstant bottom prod*ct rate.

Manipulated !ariables 'ny one or any combination o" "ollowin% may be the manip*lated $ariables.

1. team "low rate to reboiler 2. re"l*x rate.

$hapter @


3. !$erhead prod*ct with drawn rate. 4. 4ottom prod*ct withdrawn rate. 5. Water "low rate to condenser .

"oads or disturbances ollowin% are typical dist*rbances.

1. low rate o" "eed. 2. ;omposition o" "eed. 3. #emperat*re o" "eed. 4. ress*re drop o" steam across reboiler. 5. nlet temperat*re o" water "or condenser . Control sc#eme !$erall prod*ct rate is "ixed and any chan%e in "eed m*st be absorbed by chan%in% bottom prod*ct rate. #he chan%e in prod*ct rate is accomplished by direct le$el control o" reboiler i" the stream rate is "ixed "eed rate increases then $apo*r rate is approximately is constant and the internal re"l*x "low m*st increase.

$d!anta%e ince and increase in "eed rate increases re"l*x rate with $apo*r rate bein% approximately constant, then p*rity o" top prod*ct increases.

&isad!anta%e #he o$erhead chan%e depends on dynamics o" le$el control system that ad/*sts it.

$hapter @


$hapter @


$hapter +o, 

"*SI$ P&I+$IP0S OF H*/OP S%1D

$hapter @


$hapter  "*SI$ P&I+$IP0S OF H*/OP S%1D #he basic concept o" the haard and operability st*dy is to take a "*ll description o" process and to D*estion e$ery part o" it to disco$er what de$iation "rom the intention o" the desi%n can occ*re and what can be their ca*ses and conseD*ences. #he se$en %*ide words recommended in the chemical ind*stries association&;'( booklet are *sed.n addition to these words,the "ollowin% words are also *sed with precise meanin%. ntention =e$iation ;a*ses ;onseD*ences aards n 'I! st*dy,each se%ment&pipeline,piece o" eD*ipment,instr*ment,etc( is care"*lly examined and all possible de$iations "rom normal operatin% conditions are spesi"ied.ome o" %*ide words works recommended by ;' are %i$en in the "ollowin% #able. ?1ID 3O&DS

)o or )ot

)o part o" the intent is achie$ed  nothin% else

occ*rs &e.%. no "low( 3ore

' D*ntitatibe increase&e.%. "low rates  temprat*re(

' D*ntitatibe decrease&e.%. low press*re(

's well as

' D*alitati$e increase &e.%. an imp*rity(

art o"

' D*alitati$e decrease &e.%. only one o" two

components in a mixt*re(

$hapter @


>e$erse

!pposite &e.%. block "low(,the elo%ical opposite o"

!ther than

)o part o" the intent is achie$ed  somethin%

the intention

completely di""erent occ*rs &e.%."low o" wron% material.( #hese %*ide words are applied to "low,temperat*re,press*re,liD*id le$el,composition and any other $ariables a""ectin% the process.#he conseD*ences o" these de$iations on the process are then assessed and the meas*res needed to detect and correct de$iations are established.

%PS OF OP&*%I+? D8I*%IO+S 3a/or operatin% limits low #emperat*re

#ime ;ontact time eD*ence

ress*re

=esi%n cycle

;hemical reacti$ity

=istrib*tion

3echanical stresses

3ixin%

!ther operatin% limits

otspots

;orrosion

!$erheads

Crosion

>esonance

>esistance

tressin%

bearin%sAsha"ts o*lin%

<*bricatin% "a*lts

;a$itation

4locka%e

ibrations

ail*re to contain

material
pilla%e

Cxpension

;ontraction

ented material

;ycles o" acti$ities

;onstr*ction

$hapter @


Cn$ironmental "actors

=e""ecti$e

materials o" constr*ction iscosity

lant

3iscibility

CD*ipment

incomplete

*ns*pported

3eltin%A4oilin% point

CD*ipment

=ensity

CD*ipment

not ali%ned

not ti%ht apor density

3a/or

de$iations hase

tart *pAsh*t

down 'ppearance article sie

3aintnance lanned

chan%es in normal operations ;hemical composition aardo*s materials

!thers *pplyACD*ipment "ail*re =emand chan%es Fnplanned i%nition so*rce

>eactions Cxtent type

;ontrol distrib*tion
comm*nication ide reaction ;atalyst beha$ior

*man error ;limate e""ects +. acti$ity 2. #oxicity

$hapter @


n the scheme shown in the "ollowin% "i%*re soda is *nloaded "rom tank tr*nks into a stora%e tank and is trans"erred to the mixin% tank.'I! st*dy on a stora%e is brie"ly presented in the table.

$hapter G

$ost stimation

$hapter +o, C

Potential Health ffects

$hapter G

$ost stimation

$hapter C Potential Health ffects Inhalation; 3ay ca*se irritation to the respiratory tract. ymptoms may incl*de co*%hin%, sore throat, labored breathin%, and chest pain.

In!estion; n%estion o" siable amo*nts can ca*se salicylism, as e$idenced by abdominal pain, $omitin%, increased respiration, and mental dist*rbances. atalities res*ltin% "rom respiratory or cardio$asc*lar "ail*re are known. 3ean lethal ad*lt dose o" salicylates is between 20 and 0 %rams.

S'in $ontact; 3ay ca*se irritation with redness and pain.

ye $ontact; 3ay ca*se irritation, redness and pain.

First *id Measures Inhalation; >emo$e to "resh air. 5et medical attention "or any breathin% di""ic*lty.

In!estion; nd*ce $omitin% immediately as directed by medical personnel. )e$er %i$e anythin% by mo*th to an *nconscio*s person. 5et medical attention.

S'in $ontact; mmediately "l*sh skin with plenty o" water "or at least +1 min*tes. >emo$e contaminated clothin% and shoes. Wash clothin% be"ore re*se. #horo*%hly clean shoes be"ore re*se. 5et medical attention i" irritation de$elops.

ye $ontact; mmediately "l*sh eyes with plenty o" water "or at least +1 min*tes, li"tin% *pper

$hapter G

$ost stimation

and lower eyelids occasionally. 5et medical attention i" irritation persists.

+ote to Physician; 5astric la$a%e with  - 1E sodi*m bicarb to decrease absorption o" salicylate ion. ire i%htin% 3eas*res Fire;

's with most or%anic solids, "ire is possible at ele$ated temperat*res or by contact with an i%nition so*rce. xplosion;

ine d*st dispersed in air in s*""icient concentrations, and in the presence o" an i%nition so*rce is a potential d*st explosion haard. Fire xtin!uishin! Media;

Water spray, dry chemical, alcohol "oam, or carbon dioxide. Special Information;

n the e$ent o" a "ire, wear "*ll protecti$e clothin% and )!-appro$ed sel"contained breathin% apparat*s with "*ll "acepiece operated in the press*re demand or other positi$e press*re mode.

*ccidental &elease Measures entilate area o" leak or spill. Wear appropriate personal protecti$e eD*ipment as speci"ied in ection . pillsL weep *p and containerie "or reclamation or disposal. ac**min% or wet sweepin% may be *sed to a$oid d*st dispersal. mall amo*nts o" resid*e may be "l*shed to sewer with plenty o" water.

Handlin! and Stora!e

?eep in a ti%htly closed container. rotect "rom physical dama%e. tore in a cool, dry, $entilated area away "rom so*rces o" heat, moist*re and incompatibilities.

$hapter G

$ost stimation

tore in the dark. ;ontainers o" this material may be haardo*s when empty since they retain prod*ct resid*es &d*st, solids(B obser$e all warnin%s and preca*tions listed "or the prod*ct. xposure $ontrolsAPersonal Protection

' system o" local andAor %eneral exha*st is recommended to keep employee expos*res as low as possible. ecommended ractices, most recent edition, "or details. or conditions o" *se where expos*re to d*st or mist is apparent and en%ineerin% controls are not "easible, a partic*late respirator &or better "ilters( may be worn. " oil particles &e.%. l*bricants, c*ttin% "l*ids, %lycerine, etc.( are present, *se a  "ilter. or emer%encies or instances where the expos*re le$els a re not known, *se a "*ll-"ace positi$e-press*re, air-s*pplied respirator. 'ir-p*ri"yin% respirators do not protect workers in oxy%en-de"icient atmospheres. Wear protecti$e %lo$es and clean body-co$erin% clothin%. Fse chemical sa"ety %o%%les. 3aintain eye wash "o*ntain and D*ick-drench "acilities in work area. Disposal $onsiderations

Whate$er cannot be sa$ed "or reco$ery or recyclin% sho*ld be mana%ed in an appropriate and appro$ed waste disposal "acility. rocessin%, *se or contamination o" this prod*ct may chan%e the waste mana%ement options. tate and local disposal re%*lations may di""er "rom "ederal disposal re%*lations. =ispose o" container and *n*sed contents in accordance with "ederal, state and local reD*irements. acilities storin% or *tiliin% this material sho*ld be eD*ipped with an eyewash "acility and a sa"ety shower. Fse adeD*ate %eneral or local exha*st $entilation to

$hapter G

$ost stimation

keep airborne concentrations below the permissible expos*re ersonal rotecti$e CD*ipment Wear appropriate protecti$e eye%lasses or chemical sa"ety %o%%les

limits.

Wear appropriate protecti$e %lo$es to pre$ent skin expos*re. Wear appropriate protecti$e clothin% to pre$ent skin expos*re. ' respiratory protection pro%ram "ollowed whene$er workplace conditions warrant a respiratorqs *se.

Other Information

)'

>atin%sL

ealthL

+

lammabilityL

aard

+

>eacti$ityL

0

Warnin%L

W'>))5 '>3F<  W'<'< )C>!F U#C3. 3'U ;'FC >>#'#!) #! ?), CUC, ')= >C>'#!>U #>';# '$oid

Wash

with

reca*tionsL eyes,

skin

thoro*%hly

'$oid

and

a"ter

handlin%.

breathin%

?eep

d*st.

container

Fse

with

clothin%.

closed.

adeD*ate

$entilation.

irst

'idL

" swallowed, ind*ce $omitin% immediately as directed by medical personnel. )e$er %i$e anythin% by mo*th to an *nconscio*s person. 5et medical attention. n case o" contact, immediately "l*sh eyes or skin with plenty o" water "or at least +1 min*tes. 5et medical attention i" irritation de$elops or persists. " inhaled, remo$e to

"resh

air.

5et

medical

attention

"or

any

breathin%

di""ic*lty.

$hapter G

$ost stimation

$hapter +o,G $ost stimation

$hapter +o,G $ost stimation

$hapter G

$ost stimation

CD*ipment

)*mber

;apacity

;ostAeD*ipment

#otal cost

>e"erenceL

'*tocla$e



;#>

+

+0.2 m +.6 m 

eter and #immerha*se \\\

'cidi"ication tank ;entri"*%e



:.2 m

\\..



7.:: m

=ryer

+

:.91m2

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$ost stimation

ipin% cost

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Clectric cost

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O

4*ildin% &incl*din% ser$ices( &29EC O Uard impro$ement &+0EC( O
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%otal Direct $ost Indirect cost

Cn%ineerin% and *per$ision ;ost &2EC( O ;onstriction Cxpenses &0EC( ;ontractor "ee &+EC(

O

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;ontin%ency ;ost &0EC( O

%otal Indirect $ost ixed ;apital n$estment O =irect cost H ndirect cost .;.

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Product $ost 'ss*me that the ixed ;apital n$estment depreciate by strai%ht line method "or 20 years. 'ss*min% 1 E al$a%e $al*e at the end o" plant li"e. =epreciation O = O &- &-(A)  O .;.  O 0.01R.;. ) Ono. o" years O20 =O #otal #otal rod*ct ;ost O #otal ;apital n$estment 8 =epreciation O

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$ost stimation

ixed ;har%es &+2E#..;( O =irect rod*ct ;ost &11E#..;( O lant !$erhead !$erhe ad &+0E#..;( &+0E#..;( O 5eneral Cxpenses

O

lant ;apacity O 21R0 O210 ton per year &year o" 0 days( ellin% rice O #otal #otal income O ellin% rice Rprod*ction O #otal #otal ro"it be"ore #axes O ncome 8 Cxpenses O >et*rn on n$estment O #otal #otal ro"it lant o$erhead

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$ost stimation

/0//"/S +(

<*dwi%, C.C, 'pplied rocess =esi%n^, rd ed, $ol. 2, 5*l" ro"essional *blishers, 2002.

2(

<*dwi%, C.C, 'pplied rocess =esi%n^, rd ed, $ol. , 5*l" ro"essional *blishers, 2002.

(

3c?etta, @. @., Cncyclopedia o" ;hemical rocessin% and =esi%n^, Cxec*ti$e ed, $ol. +, 3arcel =ekker nc, )ew Uork, Uork, +976.

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?*ppan, ?*ppan, #., eat eat Cxchan Cxchan%er %er =esi%n =esi%n and and 4ook, 4ook, 3arcel =ekker nc., )ew Uork, Uork, 2000.

1(

eaction Cn%ineerin%L, 2nd ed, @ohn Wiley and ons nc., +972.

6(

eters, 3.. and #immerha*s, ?.=., lant =esi%n and Cconom Cconomics ics "or ;hemica ;hemicall Cn%ine Cn%ineeri erin%^, n%^, o*rth o*rth ed, 3c5raw 3c5raw ill, ill, +99+.

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4ock 4ockh*r h*rst st,, @. @.. and ark arker er,, @., @., ro roce cess ss lan lantt =esi%n^, einemann Cd*cational 4ooks
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;o*l ;o*lso son, n, @.m. @.m.,, and and >ich >ichar ards dson, on, @. @.., ;hem ;hemic ical al Cn%ineerin%^, :th ed, ol.2, 4*tterworth eminann, +99+.

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eacock, =.5., ;o*lson  >ichardsonKs ;hemical Cn%ineerin%^, rd ed, $ol, 4*tterworth einenann, +99:.

$hapter G

+0(

$ost stimation

innot, >.?., ;o*lson and >ichardsonKs ;hemical Cn%ineerin%^, 2nd ed, $ol 6, 4*tterword einemann, +99.

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?ern, =.T., rocess eat #rans"er^, 3c5raw ill nc., 2000.

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3c;abe,

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Production of Benzoic Acid

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