SEPARATION 1pt 1 In gas absorption, when the conditions at the bottom of the tower are xed and the gas ow rate is gi!en, the "imiting ow rate based on e#$i"ibri$m conditions that wi"" re#$ire innite"% ta"" tower is Se"ect one& a' minim$m "i#$id ow rate
b' maxim$m gas ow rate
c' minim$m gas ow rate
d' maxim$m "i#$id ow rate
(eedbac) The correct answer answer is& maxim$m "i#$id ow rate rate * The ease of di+c$"t% of separating components b% disti""ation is determined b% the Se"ect one& a' re"ati!e !a"ati"it%
b' !iscosit%
c' weight fraction of the components
d' mo"efraction
(eedbac) The correct answer answer is& re"ati!e !a"ati"it% !a"ati"it% - The rate e#$ation in terms of the gasphase mass transfer coe+cient transfer coe+cient is $sed in design ca"c$"ations instead of that in terms of the "i#$id phase is when Se"ect one& a' the tie "ine is hori.onta"
b' the so"$bi"it% of the so"$te in the so"!ent is !er% "ow
c' the contro""ing resistance is that of the "i#$id phase
d' the contro""ing resistance is that of the gas phase
(eedbac) The correct answer answer is& the contro""ing resistance is that of the the gas phase / A deb$tani.er is a Se"ect one& a' si.e red$ction e#$ipmant
b' $id transfer e#$ipment
c' mass transfer e#$ipment transfer e#$ipment
d' heat transfer e#$ipment transfer e#$ipment
(eedbac)
The correct answer answer is& mass transfer e#$ipment transfer e#$ipment 0 The mass transfer rate transfer rate of a materia" from one phase to another across an interface is increased b% Se"ect one& a' increassing
b' decreasing the dierence between the b$") concentration and the
concentration at the interface between the * phases
c' )eeping constant
d' ma)ing .ero
(eedbac) The correct answer answer is& increassing 2 A $nit operation in which a so"$b"e component is remo!ed from an inert so"id b% a so"!ent which preferentia""% disso"!es the so"$b"e matter from the mixt$re is )nown as& Se"ect one& a' so"!ent extraction
b' sedimentation
c' adsorption
d' "eaching
(eedbac) The correct answer answer is& adsorption 3 In a !ac$$m disti""ation co"$mn the !ac$$m is $s$a""% created b % a Se"ect one& a' !ac$$m p$mp
b' steam e4ecctor
c' centrif$ga" p$mpcompressor
(eedbac) The correct answer answer is& !ac$$m p$mp 5 In this case a so"$te in a "i#$id so"$tion is remo!ed b% contacting with another "i#$id so"!ent which is re"ati!e"% immiscib"e with the so"$tion Se"ect one& a' Absorption
b' so"id "i#$id extraction
c' 6i#$id "i#$id extraction
(eedbac) The correct answer answer is& 6i#$id "i#$id extraction extraction 7 8hen the re"ati!e !o"ati"% of * miscib"e are c"ose to 1'99 the components can be separated b% Se"ect one&
a' sedimentation
b' extracti!e disti""ation
c' simp"e fractionation
d' "ow press$re disti""ation
(eedbac) The correct answer answer is& extracti!e disti""ation disti""ation 19 To impro!e the degree of separation of the more !o"ati"e component from the "ess !o"ati"e component thro$gh disti""ation the chemica" engineer ma%, witho$t changing the other !ariab"es' Se"ect one& a' increase the reboi"er temperat$re
b' increase the co"$mn press$re
c' red$ce the co"$mn press$re
d' increase the feed temperat$re
(eedbac) The correct answer answer is& red$ce the co"$mn press$re press$re 11 :&&SEparation191&&The separation of a di"$te s"$rr% or s$spension b% gra!it% sett"ing into a c"ear $id and a s"$rr% of higher so"ids content is ca""ed ;;;;;: Se"ect one&
a' ("oatation
b' e!aporation
c' sedimentation
d' cr%sta""i.ation
(eedbac) The correct answer is& e!aporation 1* A membrane separation process where the component from a heated "i#$id phase permeates thro$gh the membrane and is remo!ed $nder "ow press$re is Se"ect one& a' micro"tration
b' dia"%sis
c' re!erse osmosis
d' per!aporation
(eedbac) The correct answer is& re!erse osmosis 1- In gas absorption,pac)ings are $sed Se"ect one&
a' to red$se the presss$re drop created b% the fo""owing gas
b' to increase the area of the contact between the gas and the "i#$id
c' to reinforce the absorption tower d$e to drag created b% the "i#$id and the
gas
d' to disseminate the heat generated to maintain isotherma" conditions
(eedbac) The correct answer is& to increase the area of the contact between the gas and the "i#$id 1/ A binar% so"$tion, where A is a "ow boi"er,exhibiting a maxim$m boi"ing point, is s$b4ected to ash disti""ation' If the feed has a concentration in A "ess than the a.eotropic point, the concentration of the disti""ate wi"" be Se"ect one& a' same
b' higher in <
c' higher in A
(eedbac) The correct answer is& higher in < 10 The temperat$re in a disti""ing co"$mn from bottom to top Se"ect one&
a' increase
b' decrease
c' maxim$m
d' between maxim$m and minim$m
(eedbac) The correct answer is& maxim$m 12 Increasing the operating press$re of a disti""ation co"$mn Se"ect one& a' sharpens separation
b' re#$ires "ess heat in the feed heater
c' does not ma)e a dierence in components separation
d' ma)es separation di+c$"t
(eedbac) The correct answer is& ma)es separation di+c$"t 13 The degrees of freedom associated with ternar% disti""ation process according to the =ibb>s phase r$"e is Se"ect one&
a' 0
b' *
c' /
d' -
(eedbac) The correct answer is& 15 In a disti""ing co"$mn the highest press$re wi"" be at & Se"ect one& a' the top
b' the bottom
c' the feed p"ate
d' between the feed p"ate and the top
(eedbac) The correct answer is& the bottom 17 The press$re drop a"ong a pac)ed tower is Se"ect one& a' direct"% proportiona" to the s#$are of the mass ow rate
b' in!erse"% proportiona" to the s#$are of the mass ow rate
c' direct"% proportiona" to the mass ow rate
d' in!erse"% proportiona" to the mass ow rate
(eedbac) The correct answer is& direct"% proportiona" to the s#$are of the mass ow rate *9 8hen the "i#$id ow rate is xed and the composition of the "i#$id and the gas at the bottom of the absorption tower are xed , the "imiting ow rate to gi!e innite"% ta"" tower becomes Se"ect one& a' the minim$m ow of the rate of the !apor
b' the minim$m "oading of the "i#$id
c' the maxim$m ooding !e"ocit% of the !apor
d' the maxim$m ow of the rate of the !apor
(eedbac) The correct answer is& the minim$m ow of the rate of the !apor *1 In a gas absorption co"$mn the press$re of the "ean gas is expected to be Se"ect one& a' higher than
b' "ower than
c' the same as
d' do$b"e the press$re of the rich gas entering the co"$mn
(eedbac) The correct answer is& "ower than ** It is not !er% nessesar% to correct the rate e#$ation for the phase drift enco$ntered d$ring gas absorption,since the height ca"c$"ated is Se"ect one& a' based on the same percentage reco!er% an%wa%
b' based on e#$imo"a" co$nter di$sion an%wa%
c' s"ight"% $nder designed an%wa%
d' s"ight"% o!erdesigned an%wa%
(eedbac) The correct answer is& s"ight"% o!erdesigned an%wa% *- In a twocomponent ash disti""ation process, when the operating press$re is specied, the concentration of the disti""ate ma% be impro!ed in the more !o"ati"e component if Se"ect one& a' the amo$nt of disti""ation is increase
b' the operating temperat$re is decrease
c' none of the abo!e
d' the operating temperat$re is increase
(eedbac) The correct answer is& the operating temperat$re is decrease */ 8hen the feed to the co"$mn is a sat$rated "i#$id,the feed "ine is Se"ect one& a' !ertica"
b' inc"ined to the right
c' hori.onta"
d' inc"ined to "eft
(eedbac) The correct answer is& !ertica" *0 ?ac$$m disti""ation is resorted to in order to Se"ect one& a' $se the thinner she"" p"ates for the co"$mn
b' red$ce the n$mber of tra%s in the co"$mn
c' obtain more bottom prod$cts
d' a!oid high feed and reboi"er temperat$res
(eedbac) The correct answer is& red$ce the n$mber of tra%s in the co"$mn *2 In teaching, the partic"e si.e in$ences the extraction rate' The sma""er si.e, I the greater is the interfacia" area between the so"id and the "i#$id II the sma""er is the distance the so"$te m$st di$se written the so"id III the "ower is the rate of transfer of materia" Se"ect one& a' both I @ II
b' both II and III
c' I on"%
d' II on"%
(eedbac) The correct answer is& both I @ II *3 The primar% reason wh% c"ose team is $sed in an open batch steam disti""ation is to& Se"ect one& a' s$pp"% the heat needed b% !apori.ing "i#$id
b' increase the operating temperat$re
c' increase the operating press$re
d' increase the n$mber of degrees of freedom
(eedbac) The correct answer is& increase the n$mber of degrees of freedom *5 The recent a!ai"abi"it% of digita" comp$ters res$"ted in the de!e"opment of man% ana"%tica" expressions for the e!a"$ation of !a"$es'8hich of the items be"ow is a so$rce of ana"itica" method for !a"$es& i'NRT6 ii'8i"son e#s' iii'BNICBAD i!=PA Se"ect one& a' iii on"%
b' I and i! on"%
c' none among the choices
d' a"" are so$rces
(eedbac) The correct answer is& a"" are so$rces *7 At minim$m re$x ratio, the n$mber of p"ates is Se"ect one& a' minim$m
b' between minim$m and maxim$m
c' innite
d' maxim$m
(eedbac) The correct answer is& innite -9 In the remo!a" of a so"$te from a water phase b% "i#$id extraction $sing a membrane, it is ad!antageo$s to $se Se"ect one& a' an ass%metric membrane
b' a po"%mer membrane
c' an% poro$s membrane
d' a h%drophobic membrane
(eedbac) The correct answer is& a h%drophobic membrane -1 In a simp"e batch disti""ation, the boi"ing point of the disti""ate prod$ct compared to the resid$e is Se"ect one& a' the same
b' higher
c' "ower
(eedbac) The correct answer is& "ower -* 8hen the two"m theor% is app"ied to gas absorption, the o!era"" resistance can be expressed in terms of the indi!id$a" resistance in the form 1%a F 1)%aGm)xa This is possib"e beca$se of an important ass$mption'This ass$mption is Se"ect one& a' the tie "ine has a s"ope between 9 and 1@
b' the operating "ine is "inear
c' the so"$te forms an idea" so"$tion with the so"!ent
d' the s"ope of the e#$i"ibri$m c$r!e near the tie "ine is "inear
(eedbac) The correct answer is& the s"ope of the e#$i"ibri$m c$r!e near the tie "ine is "inear -- 8hen the re"ati!e !o"ati"% of * miscib"e are c"ose to 1'99 the components can be separated b% Se"ect one& a' simp"e fractionation
b' extracti!e disti""ation
c' "ow press$re disti""ation
d' sedimentation
(eedbac) The correct answer is& extracti!e disti""ation -/ The ma4or prob"em in "eaching is to promote di$tion of the so"$te o$t of the so"id and into the "i#$id'The most eecti!e wa% of doing this is& Se"ect one& a' to red$ce the so"id to the sma""est si.e feasib"e
b' to $se co$nter c$rrent operation
c' none of the abo!e
d' to $se cross ow e!aporation
(eedbac) The correct answer is& to red$ce the so"id to the sma""est si.e feasib"e -0 Hc DabeThie"e method to determine the theoretica" n$mber of stages, ma% be app"ied with acceptab"e res$"ts if Se"ect one& a' heat "osses and heat of so"$tion are !er% neg"igib"ee
b' the components ha!e high re"ati!e !o"ati"it%
c' the components ha!e dierent boi"ing points
d' the s%stem fo""ow Tro$ton@
(eedbac) The correct answer is& the s%stem fo""ow Tro$ton@ -2 In disti""ation where there are two components and both components are fo$nd in both phases,on"% one !ariab"e e'g', "i#$id pphase concentration, can be changed independent"% if the press$re is xed and temperat$re and !apor phase concentration wi"" fo""ow' Is this Se"ect one& a' (A6SE
b' tr$e
(eedbac) The correct answer is& tr$e -3 This concerns the remo!a" of a so"$te s$ch as a sa"t from a so"$tion b% precipitating the so"$te from the so"$tion Se"ect one& a' Ji$sion
b' e!aporation
c' cr%sta""i.ation
d' dr%ing
(eedbac) The correct answer is& cr%sta""i.ation -5In batch open steam disti""ation, the so"$tion to be open steam disti"""ed sho$"d be Se"ect one& a' s"ight"% immiscib"e in water
b' containing "arge non!o"ati"e imp$rities
c' comp"ete"% immiscib"e in water
d' miscib"e in water
(eedbac) The correct answer is& comp"ete"% immiscib"e in water -7 The method of separating a partic$"ar gaseo$s component from a mixt$re of gases d$e to their dierences in so"$bi"it% in a "i#$id phase is Se"ect one& a' disti""ation
b' extraction
c' adsorption
d' absorption
(eedbac)
The correct answer is& absorption /9 The re"ati!e !o"ati"it% of the mixt$re at the a.eotropic point where the so"$tion exhibits minim$m boi"ing point is Se"ect one& a' e#$a" to 1
b' greater than 1
c' "ess than 1
(eedbac) The correct answer is& e#$a" to 1
/1 A 09K b% weight ben.eneto"$ene mixt$res is fed to a co"$mn at 159o( and 1 atm' The condition of this feed is Se"ect one& a' s$b coo"ed
b' sat$rated "i#$id
c' !apor
d' mixt$re of "i#$id and !apor
(eedbac) The correct answer is& s$b coo"ed
/* This process in!o"!es the separation of so"$te from a $id b% di$sion of this so"$te from a "i#$id or gas thro$gh a semipermeab"e membrane barrier to another "i#$id Se"ect one& a' Jisti""ation
b' membrane separation
c' absorption
(eedbac) The correct answer is& membrane separation /- Agitation of the "i#$id in$ences the rate of extraction' Agitation osf so"!ent is important beca$se I it pre!ents sedimentation it increases edd% di$sion III it increases the transfer of materia" from the s$rface of the partic"es to the b$") of so"$tion Se"ect one& a' I on"%
b' both I and II
c' II on"%
d' both II and III
(eedbac) The correct answer is& both II and III
// In a simp"e batch disti""ation, the boi"ing point of the disti""ate prod$ct compared to the resid$e is Se"ect one& a' "ower
b' higher
c' the same
(eedbac) The correct answer is& "ower /0 In a gas absorption tower, mass transfer occ$rs primari"%& Se"ect one& a' from the gas phase to the pac)ing
b' from the gas phase to the "i#$id phase
c' from the "i#$id phase to the gas phase
d' from the "i#$id phase to the pac)ing
(eedbac) The correct answer is& from the "i#$id phase to the pac)ing /2 8hen the gas ow rate ind$ces ooding in a pac)ed co"$mn gas absober,this is best remedied if the percent reco!er% of the so"$te is to be maintained b% Se"ect one&
a' increasing the diameter of the co"$mn
b' increasing the height of the co"$mn
c' red$cing the !apor ow rate
d' red$cing the "i#$id ow rate
(eedbac) The correct answer is& increasing the diameter of the co"$mn /3 In nonidea" "eaching conditions, the tie "ines s"ant to the right indicating that the so"$te is more high"% concentrated in the $nderow beaca$se' Se"ect one& a' the so"!ent and the so"$te are comp"ete"% miscib"e
b' of a partia""% miscib"e carrier or incomp"ete sett"ing
c' a"" of the choices
d' of e#$i"ibri$m so"$bi"it% or f in comp"ete "eaching
(eedbac) The correct answer is& of e#$i"ibri$m so"$bi"it% or f in comp"ete "eaching /5 The temperat$re a"so aects the rate of extraction' In most cases, the so"$bi"it% of the materia" which is being extracted wi"" increase with temperat$re to I gi!e a higher rate of extraction II increase the di$sion coe+cient III pre!ention of en.%me action
Se"ect one& a' I on"%
b' both II and III
c' II on"%
d' both I and II
(eedbac) The correct answer is& both I and II /5 In a twocomponent ash disti""ation process, when the operating press$re is specied, the concentration of the disti""ate ma% be impro!ed in the more !o"ati"e component if Se"ect one& a' the operating temperat$re is decrease
b' the amo$nt of disti""ation is increase
c' the operating temperat$re is increase
d' none of the abo!e
(eedbac) The correct answer is& the operating temperat$re is decrease /7 The temperat$re of the so"$tion Prob' * as disti""ation progress at constant operating press$re is
Se"ect one& a' constant
b' increasing
c' decreasing
(eedbac) The correct answer is& constant 09 Thera are two $nderowo!erow "eaching conditions name"% idea" and non idea"'The idea" "eaching condition exist if& Se"ect one& a' a"" of the choices are correct
b' s$+cient contact time for the so"!ent to penetrate the so"$te comp"ete"% is
permitted
c' the carrier so"id is comp"ete"% inert and is not disso"!ed or entrained in the
so"!ent d' the so"$te is innite"% so"$b"e in the so"$b"e
(eedbac) The correct answer is& a"" of the choices are correct 0* In the case of a straight or conca!e downward operating "ine and a straight or conca!e $pward e#$i"ibri$m "ine, the minim$m "i#$idrate is that at which the Se"ect one&
a' the operating "ine 4$st to$ches the e#$i"ibri$m "ine on top of the
tower
b' the s"ope of the operating "ine is sma""er than the e#$i"ibri$m "ine
c' the operating "ine 4$st to$ches the e#$i"ibri$m "ine at the bottom of the tower
d' the operating "ine intersects the e#$i"ibri$m "ine at the midd"e of the tower
(eedbac) The correct answer is& the operating "ine 4$st to$ches the e#$i"ibri$m "ine at the bottom of the tower 0* In pac)ed co"$mns,the press$re drop for irrigated pac)ing is a"wa%s greater than the press$re drop for dr% pac)ings beca$se Se"ect one& a' the s$rface of dr% pac)ing is smoother
b' the ow area of dr% pac)ing is greater
c' none of the abo!e
d' the drag friction is "esser than the s)in friction for dr% pac)ing
(eedbac) The correct answer is& the ow area of dr% pac)ing is greater
0- The dierence between stage operation LAM and a contin$o$s phase contact operation L
concentration changes b' that an idea" L
c' that LAM is coc$rrent ow whi"e L
d' that LAM %ie"ds discreet concentration changes whi"e L
concentration changes (eedbac) The correct answer is& that LAM %ie"ds discreet concentration changes whi"e L
b' re#$ires "ess heat in the feed heater
c' sharpens separation
d' does not ma)e a dierence in components separation
(eedbac) The correct answer is& ma)es separation di+c$"t
00 The mechanism of mass transfer in a gas absorber is best described b% Se"ect one& a' Two"m stor%
b' S$rfaceRenewa" theor%
c' the Penetration Theor%
d' Dhi"tonDo"b$rn Ana"og%
(eedbac) The correct answer is& Two"m stor% 02 In a stripping or desorption operation, the e#$i"ibri$m c$r!e is Se"ect one& a' abo!e the operating "ine
b' "inear
c' be"ow the operating "ine
d' perpendic$"ar with the tie "ine
(eedbac) The correct answer is& abo!e the operating "ine 03 Jescription is another term for Se"ect one&
a' stripping
b' deph"egmation
c' ash disti""ation
d' rectication
(eedbac) The correct answer is& stripping 05 (or an absorberLmass transfer from gas into "i#$idM the operating "ines a"wa%s Se"ect one& a' interest at one@
b' "ies abo!e the e#$i"ibri$m@
/0so"$bi"it% c$r!e c' "ies be"ow the e#$i"ibri$m@
d' coincides the e#$i"ibri$m c$r!e
(eedbac) The correct answer is& "ies abo!e the e#$i"ibri$m@ 07 The o!era"" height of a transfer $nit based on the gas phase wi"" e#$a" the gas phase indi!id$a" TB,% when Se"ect one&
a' the gsa phase resistance is !er% sma"" copmared with the "i#$id phase
b' the e#$i"ibri$m c$r!e is "enear
c' the operating "ine is "enear
d' the "i#$id@
(eedbac) The correct answer is& the "i#$id@ 29 (or a mass transfer to ta)e p"ace, there m$st be Se"ect one& a' heat present
b' more than two components in!o"!e
c' entha"p% change
d' concentration gradient
(eedbac) The correct answer is& concentration gradient 21 The $se of a "i#$id rate far abo!e the minim$m !a"$e wi"" res$"t in Se"ect one& a' none of the choices
b' sma"" n$mber of p"ates
c' innite n$mbers of p"ate
d' minim$m n$nber of p"ates
(eedbac) The correct answer is& sma"" n$mber of p"ates 2* The distrib$tion coe+cient of nhexane at 19 atm abs and *99oD is Se"ect one& a' *@
/22 b' 1@
c' none
d' 9@
(eedbac) The correct answer is& 1@ 2- In gas absorption, when the conditions at the bottom of the tower are xed and the gas ow rate is gi!en, the "imiting ow rate based on the e#$i"ibri$m conditions that wi"" re#$ire innite"% ta"" tower is Se"ect one& a' minim$m "i#$id ow rate
b' maxim$m "i#$id ow rate
c' minim$m gas ow rate
d' maxim$m ow rate
(eedbac) The correct answer is& maxim$m "i#$id ow rate 2/ The ph%sica" separation of component in a miscib"e mixt$re b% sim$"taneo$s e!aporation and condensation is Se"ect one& a' absorption
b' disti""ation
c' extraction
d' dr%ing
(eedbac) The correct answer is& disti""ation 20 Open steam binar% rectication ma% be app"ied with s$ccess if the "ess !o"ati"e component is Se"ect one& a' water
b' acetone
c' a"coho"
d' ben.ene
(eedbac) The correct answer is& water 22 The $nit operations bb% which the "ighter components in a m$"ticomponent so"$tion of !o"ati"e "i#$ids are separated from the hea!ier components is Se"ect one& a' absorption
b' dr%ing
c' disti""ation
(eedbac) The correct answer is& disti""ation
23 In a membrane separation process, an ass%metric membrane refers to Se"ect one& a' a membrane that is not $niform in thic)ness
b' a composite po"%mer and poro$s membrane
c' a series of po"%mer membranes
d' a membrane that is not s%mmetrica" in thic)ness
(eedbac) The correct answer is& a composite po"%mer and poro$s membrane 25 A wettedwa"" co"$mn is $s$a""% $sed to determine mass transfer coe+cient experementa""% beca$se ;;;;; is acc$rate"% )nown' Se"ect one& a' concentration gradient of A
b' mass transfer area
c' the ow rate of gas and "i#$id
d' thic)ness of the "aminar "ms ad4acent to the interface
(eedbac) The correct answer is& mass transfer area 27 In the choice of so"!ent for gas absorption, one of the properties to be consideered is Se"ect one& a' so"!ent sho$"d be $n$s$a"
b' so"!ent sho$"d ha!e a "ow !apor press$re
c' so"!ent sho$"d ha!e "ow boi"ing point
d' so"!ent sho$"d be high"% !isco$s
(eedbac) The correct answer is& so"!ent sho$"d ha!e a "ow !apor press$re 39 The primar% reason wh% c"ose team is $sed in an open batch steam disti""ation is to& Se"ect one& a' s$pp"% the heat needed b% !apori.ing "i#$id
b' increase the n$mber of degrees of freedom
c' increase the operating temperat$re
d' increase the operating press$re
(eedbac) The correct answer is& increase the n$mber of degrees of freedom 31 Bsing the Antoine e#$ation, the !apor press$re of tetrah%drof$ran at 59oD is estimatedto be ;;;;; in torr' Se"ect one& a' 113-
b' *0*2
c' 1015
d' *999
(eedbac) The correct answer is& 1133* In the disti""ation the coo"ed "i#$id stream ret$rned to the co"$mn to coo" a p"ate or stage is ca""ed Se"ect one& a' reboi"
b' feed
c' bottms
d' re$x
(eedbac) The correct answer is& re$x 3- (or moderate"% so"$b"e gases with re"ati!e"% "itt"e intersection between the gas and "i#$id mo"ec$"es, the "aw which app"ies most to estab"ish e#$i"ibri$m re"ationship is Se"ect one& a' none of the abo!e
b' enr%@
c' Ja"ton@
d' Rao$"t@
-7s "aw (eedbac) The correct answer is& enr%@ 3/ In an absorption tower pac)ings are p"aced inside to Se"ect one& a' "" $p !oid spaces
b' red$ce press$re drop across the tower
c' pro!ide a bigger mass transfer area
d' strengthen ther towert
(eedbac) The correct answer is& pro!ide a bigger mass transfer area 30 Tha ana"og% between mass and heat transfer is comp"ete when Se"ect one& a' the moment$m transfer rate is neg"igib"e
b' the temperat$re gradient and concentration gradient are e#$a"
c' the resistance to mass and heat transfer are neg"igib"e
d' no con!icti!e $x or phase drift in!o"!ed
(eedbac) The correct answer is& no con!icti!e $x or phase drift in!o"!ed 32 8hen the mo"a" "atent heat of !apori.ation of the binar% s%stem is !er% m$ch dependent on concentration, the most appropriate method to $se to determine the n$mber of idae" stage is Se"ect one& a' (ens)e Bnderwood method
b' Hc DabeThie"e method
c' PonchonSa!arit method
d' 6ewisHatheson method
(eedbac) The correct answer is& PonchonSa!arit method 33 A heat transfer e#$ipment to con!ert !apor to "i#$id is ana & Se"ect one& a' sti""
b' condenser
c' reboi"er
d' e!aporator
(eedbac) The correct answer is& condenser 35 In the case of a straight or conca!e downward operating "ine and a straight or conca!e $pward e#$i"ibri$m "ine, the minim$m "i#$idrate is that at which the Se"ect one& a' the operating "ine intersects the e#$i"ibri$m "ine at the midd"e of the tower
b' the operating "ine 4$st to$ches the e#$i"ibri$m "ine at the bottom of the
tower
c' the operating "ine 4$st to$ches the e#$i"ibri$m "ine on top of the tower
d' the s"ope of the operating "ine is sma""er than the e#$i"ibri$m "ine
(eedbac) The correct answer is& the operating "ine 4$st to$ches the e#$i"ibri$m "ine at the bottom of the tower 37 In mass transfer, a transfer $nit means that Se"ect one& a' the a!erage dri!ing force is e#$a" to $nit%
b' the mass transfer coe+cient wi"" aprroach $nit%
c' the concentration range is e#$a" to the a!erage dri!ing force
d' a mo"e of so"$te is transferred in a$nit height
(eedbac) The correct answer is& the concentration range is e#$a" to the a!erage dri!ing force 59 The $nit operation b% which miscib"e "i#$ids are separated from one another thro$gh heat and mass transfer is Se"ect one& a' sedimentation
b' "tration
c' extraction
d' disti""ation
(eedbac) The correct answer is& disti""ation 51 In teaching, the partic"e si.e in$ences the extraction rate' The sma""er si.e, I the greater is the interfacia" area between the so"id and the "i#$id II the sma""er is the distance the so"$te m$st di$se written the so"id III the "ower is the rate of transfer of materia" Se"ect one& a' II on"%
b' both II and III
c' I on"%
d' both I @ II
(eedbac) The correct answer is& both I @ II 5* It is a $nit operation which in!o"!es in the mass transfer of so"$b"e materia"s from the "i#$id phase to the gseo$s phase Se"ect one& a' dr%ing
b' desorption
c' absorption
d' h$midication
(eedbac) The correct answer is& desorption 5- A reboi"er pro!ides heat to the Se"ect one& a' the feed
b' the intermediate re$x
c' top
d' the bottom of a disti""ation co"$mn
(eedbac) The correct answer is& the bottom of a disti""ation co"$mn 5/ Strict"% spea)ing, the re"ati!e !o"ati"it% of most idea" binar% so"$tion is Se"ect one& a' not aected b% temperat$regreat"% aected b% temperat$re
b' great"% aected b% temperat$re
c' s"ight"% aected b% temperat$re
(eedbac) The correct answer is& s"ight"% aected b% temperat$re 50 The disti""ation process in!o"!es& Se"ect one& a' moment$m transfer
b' heat transfer
c' heat and mass transfer
d' mass transfer
(eedbac) The correct answer is& heat and mass transfer
-pts 1 Jisti""ation& Hinim$m n$mber of theoretica" tra%s can be obtained at Se"ect one& a' Hinim$m Re$x
b' Tota" Re$x
(eedbac) The correct answer is& Tota" Re$x * One h$ndred mo"es per ho$r of so"$tion containing 59 mo"es of A, the rest < is s$b4ected to a simp"e contin$o$s disti""ation' J mo"es of disti""ate containing 3* mo"es A is obtained' If A is !e times more !o"ati"e than <, the concentration of A in the disti""ate is Se"ect one& a' none of these
b' 9'50
c' 9'59
d' 9'0--
(eedbac) The correct answer is& 9'50 - Jisti""ation& if the feed is "i#$id at boi"ing point the # "ine is Se"ect one& a' /0
b' ori.onta"
c' !ertica"
(eedbac) The correct answer is& !ertica" / (or gas absorption where no chemica" reaction occ$rs, the height e#$i!a"ent to a theoretica" p"ateLETPM for a norma" pac)ing si.e of 09 mm ma% be estimated to be Se"ect one& a' 9'71'9m
b' 9'39'7 m
c' 9'/9'0m
d' 9'09'3m
(eedbac)
The correct answer is& 9'39'7 m 0 It has been determined that the e#$i!a"ent TB and NTB os f a pac)ed absorption tower are 9'50 ft and 10,resfecti!e"%' If the same separation can be done in a 19 p"ate absorption tower,then the ETP isft' Se"ect one& a' 1*'30none
b' 1'*30
c' 9'023
(eedbac) The correct answer is& 1'*30 2 A "i#$id mixt$re containing /0K ben.ene and 00K to"$ene b% weight is to be fed into a fractionating co"$mn at a rate of 0999)ghr' The feed rate )gmo"shr is Se"ect one& a' 05'59"bmo"shr
b' 05'59
c' *5'5/2
d' 05'3/
(eedbac) The correct answer is& 05'3/
3 If the entha"ph% of sat$rated !apor at *99o( referred to -*o( is 1-99 bt$"b whi"e the entha"ph% of sat$rated "i#$id LDp1M refered to 9o( is /99
b' 799
c' 7-*
d' 525
(eedbac) The correct answer is& 525
b' 5th
c' 1-th
d' 1*th
(eedbac) The correct answer is& 11th
7 Jisti""ation& the main ass$mption in this method is that there m$st be e#$imo"ar o!erow thro$gh the tower between the feed in"et and the top tra% and the feed in"et and bottom tra%' Se"ect one& a' PonchonSa!arit
b' HcDabeThie"e
(eedbac) The correct answer is& HcDabeThie"e 19 The percentage change in the boi"ing point of a *9mo"eK so"$tion of ben.ene to"$ene so"$tion when the press$re is increased from 1 atm to * atm is Se"ect one& a' *0'0Kincrease
b' 19'0Kincrease
c' 19'0K decrease
d' *0'0K decrease
(eedbac) The correct answer is& *0'0K decrease 11 The press$re drop ind$ce in a pac)ed co"$mn containing 1in namina" si.e te""erettes for a ow rate of gas of 1099 "bhrs# ft and -999 "bhrs# ft of "i#$id is estimated to be Se"ect one&
a' *
b' 9'/
c' 9'3
d' 1'0
(eedbac) The correct answer is& 9'3 1* Jimension"ess n$mber dened as the ratio of moment$m di$si!it% and mass di$si!it% and is $sed to characteri.e $id ows in which there are sim$"taneo$s moment$m and mass di$sion Se"ect one& a' schmidt
b' prandt"
c' b"ot
d' N$sse"t
(eedbac) The correct answer is& schmidt 1- One h$ndred mo"es per ho$r of so"$tion containing 59 mo"es of A, the rest < is s$b4ected to a simp"e contin$o$s disti""ation' J mo"es of disti""ate containing 3* mo"es A is obtained' If A is !e times more !o"ati"e than <, the concentration of A in the disti""ate is
Se"ect one& a' 9'59
b' 9'50
c' none of these
d' 9'0--
(eedbac) The correct answer is& 9'50 1/ The mo"e fraction of so"$te entering a gas absorber is 9'*0' If the percentage reco!er% is 30 percent, then the mo"e fraction of the so"$te "ea!ing the tower wi"" be Se"ect one& a' 9'9327
b' 9'95--
c' 9'92*0
d' 9'103
(eedbac) The correct answer is& 9'9327
0pts
1 A gas mixt$re at 1'9 atm press$re abs containing air and DO* is contacted in a sing"estage mixer contin$o$s"% with p$re water at *7-' The two exit gas and "i#$id streams reach e#$i"ibri$m' The in"et gas ow rate is 199 )gmo"h, with a mo"e fraction of DO* of %A*F9'*9' the "i#$id ow rate entering is -99 )gmo"waterh' Da"c$"ate the amo$nts and compositions of the two o$t"et phasesL)gmo"hM' Ass$me that water does not !apori.e to the gas phase'enr%>s "aw constant at *7- is 9'1/*x19/atmmo" frac Se"ect one& a' 199
b' 61
c' *99 ?1
d' 109 ?1
e' 61
f' 61
g' *09
h' 109
i' 61
4' -99 ?1
)' *99
"' *09?1
(eedbac) The correct answer is& 61 * Doconot oi" is to be prod$ce from dr% copra in two stages'(irst, thro$gh expe""ers to s#$ee.e o$t part of the cocon$t oi" and then thro$gh a co$nter c$rrent m$"ti stage so"!ent extraction process' After expe""ing, the dr% copra ca)e contains *9K resid$a" oi"' In the so"!ent extraction operation, 79K of the rasid$a" oi" in the expe""er ca)e is extracted as a so"$tion containing 09K b% weights oi"' If fresh so"!ent is $sed and one )g of so"$tion with e!er% * )g of inso"$b"e co)e is remo!ed with $nderow, the n$mber of idea" stages re#$ired is Se"ect one& a' 3
b' 0
c' /
d' 2
(eedbac) The correct answer is& 0 - A "i#$id mixt$re containing /0K ben.ene and 00K to"$ene b% weight is to be fed into a fractionating co"$mn at a rate of 0999)ghr' The feed rate )gmo"shr is Se"ect one&
a' 05'59"bmo"s@
b' *5@
/25/2 c' 05@
d' 05@
(eedbac) The correct answer is& 05@ / 8hat wi"" be the concentration of ox%gen disso"!ed in water at *75 when the so"$tion is in e#$i"ibri$m with air at 1 atm tota" press$re The enr%>s "aw constant is /'-5x19/atmmo" IM fraction and the partia" press$re pAof ox%gen in air is 9'*1 atm' Se"ect one& a' /'7*x190
b' /'5x192
c' ' 5'/x192
d' 7'/*x19/
(eedbac) The correct answer is& /'5x192 0 A s"$rr% a)ed so%beans weighing 199)g contains 30)g inert so"ids and *0 )g of so"$ti$on weight K oi" and 79 weight K so"!ent hexane' This s"$rr% is contacted with
199 )g p$re hexane in a sign"e stage so that tha !a"$e of retention for the o$t"et $nderow is 1'0 )g of inso"$b"e so"id per )g so"!ent in the $dhering so"$tion' The compositon of $nderow "ea!ing the extraction stage in percent b% weight oi" is Se"ect one& a' 1'0
b' 9'-*'-
c' 9'5
(eedbac) The correct answer is& 9'5 2 8hat wi"" be the concentration of ox%gen disso"!ed in water at *75 when the so"$tion is in e#$i"ibri$m with air at 1 atm tota" press$re The enr%>s "aw constant is /'-5x19/atmmo" IM fraction and the partia" press$re pAof ox%gen in air is 9'*1 atm' Se"ect one& a' /'7*x190
b' /'5x192
c' ' 5'/x192
d' 7'/*x19/
(eedbac) The correct answer is& /'5x192
3 A s"$rr% a)ed so%beans weighing 199)g contains 30)g inert so"ids and *0 )g of so"$ti$on weight K oi" and 79 weight K so"!ent hexane' This s"$rr% is contacted with 199 )g p$re hexane in a sign"e stage so that tha !a"$e of retention for the o$t"et $nderow is 1'0 )g of inso"$b"e so"id per )g so"!ent in the $dhering so"$tion' The compositon of $nderow "ea!ing the extraction stage in percent b% weight oi" is Se"ect one& a' 1'0
b' 9'-*'-
c' 9'5
(eedbac) The correct answer is& 9'5 5 :&&SEparation192&&The ratio between partia" press$re of water !apor in air and the !apor press$re of the water at A the air temperat$re m$"tip"ied b% 199 is;;;;;: Se"ect one& a' @
-3Sat$ration b' @
c' @
d' @
(eedbac) The correct answer is& @
7 8hat wi"" be the concentration of ox%gen disso"!ed in water at *75 when the so"$tion is in e#$i"ibri$m with air at 1 atm tota" press$re The enr%>s "aw constant is /'-5x19/atmmo" IM fraction and the partia" press$re pAof ox%gen in air is 9'*1 atm' Se"ect one& a' /'7*x190
b' ' 5'/x192
c' /'5x192
d' 7'/*x19/
(eedbac) The correct answer is& /'5x192
19 T$ng mea" containing 00K oi" is to be extracted at a rate of /,999 "b per ho$r $sing nhexane containign 0K wt oi" as so"!ent' A co$nterc$rrent m$"tip"e stage extraction s%stem is to be $sed' The mea" retains * "b of so"!ent per po$nd of oi" free mea" whi"e the resid$a" chagre contain 9'11 "b oi" per "b oi" free mea" whi"e the prod$ct is compose of 10 wt percent of oi"' The theoretica" n$mber of idea" stages is Se"ect one& a' /
b' -
c' 0
d' 2
(eedbac) The correct answer is& /
11 In a sa"t reco!er% p"ant, roc) sa"t is being "eached to prod$ce ind$stria" sa"t in a contin$o$s co$nter c$rrent s%stem consisting of twoL*M idea" stages $sing water as teaching medi$m' The a!erage composition of the roc) sa"t is & inerts F 39K, so"$b"e sa"ts F*0K, moist$re F0K, a"" percentage b% weight' The $nderow from each stage contains 9'-)g of so"$tion per )g inerts'The p"ant "eaches 09 HT of roc) sa"t per da% $sing 09 HT of water' The #$antit% of so"$b"e sa"ts reco!ered in HTda% is Se"ect one& a' 1/
b' 11@
c' 1*@
d' 1-@
/21 (eedbac) The correct answer is& 1*@ 1* Raw g%ps$m from a ferti"i.er p"ant is being "eached o$t of its sa"tLNaD"M content is a * step contin$o$s co$nter c$rrent s%stem $sing sa"tfree water as "eaching medi$m' The $nderow, DaSO/ s"$rr% is then sent to a drier to obtain the na" prod$ct' The operating data are as fo""ows&Raw g%ps$m feed F 19 HTda%Sa"t content of raw g%ps$m F 1Kwt8ater feed rate F 79 m-da%8taer content of s"$ rr% F 9'97 HT *O per HT DaSO/,brQ