SHELL & TUBE_HEAT-EXCHANGER_DESIGN

DESCRIPTION OF PROBLEM o

43,200 lb/hr of 35 API distillate is cooled from 250 to 120 F using cooling water from 85 to 120oF. Available for service is a 19.25 in. ID 1-2 exchanger having 204 tubes 3/4in. OD, 16 BWG, 16'0" long on 1-in square . Baffles are spaced at 5in. Apart, and the bundle is arranged for 4 passes. Calculate pressure drop & dirt Factor. What is the optimum outlet water temperature? (Allowable Pressure Drop is 10.0 psi)

DATA AVAILABLE

HOT FLUID

Inlet Temperature Outlet Temperature Thermal Conductivity Specific Heat Capacity Viscosity Mass Flow Rate specific Gravity

PARAMETERS

Heat Transfer

Tin Tout k Cp μ m s

UNIT Btu/hr

250 120 0.077 0.52 5.268 43000 0.815

NOTATION

Q

COLD FLUID

UNIT

85 120 0.3615 1 1.815 83051.42857 1

Btu/(hr)(ft2)(°F/ft) Btu/(lb)(°F) lb/(ft)(hr) lb/hr -

HOT FLUID

COLD FLUID

2906800

2906800

°F °F

Calorific Temperature

o

F

TC

156.4

UNIT ft2

NOTATION as GS

VALUES

94.8

SHELL SIDE CALCULATION PARAMETERS

Flow area Mass Velocity Reynolds Number Factor for Heat Transfer Prandtl Number ho/φt μ at wall temperature Viscosity Ratio Heat Transfer Coefficient

2

lb/(hr)(ft ) lb/(ft)(hr) Btu/hr

CLEAN OVERALL HEAT TRANSFER COEFFICIENT

Re JH Pr μw φs ho

0.167100694 257329.8701 3858.971097 35 35.5761039 112.1978341 7.26 0.956091111 107.2713518

UC

94.12363295

CLEAN OVERALL HEAT TRANSFER COEFFICIENT

UD

72.02733936

DIRT FACTOR

RD

0.003259293

OPTIMUM OUTLET WATER TEMPERATURE

to

130.7371768

Pressure Drop Calculation SHELL SIDE Friction factor Number of Crosses Pressure Drop (psi)

f N+1 ∆Ps

0.0026 38.4 3.300501834

THE HEAT EXCHANGER IS SATISFACTORY FOR THE SERVICE

Friction factor Tube side Prssure Drop Return Pressure Drop Total Pressure Drop

f ∆Pt ∆Pr ∆PT

ADDITIONAL DATA ( 1-2 exchanger) UNIT

Shell ID Baffle Spacing passes

Di

No. of Tubes

B n NT

OD of Tubes

do

ID of Tubes Length BWG / Pitch

di L PT

Tube Pitch Clearence between Tubes Eq. Diameter

C' De

Flow Area per Tube

at

External Surface Per lin. ft Velocity through Tubes

a'' V g

Acceleration of Gravity

19.25 5 4 204 0.75 0.0517 16 16/1-in sq. 1 0.25 0.079 0.302 0.1963 2.8 32.2

inch inch ft ft inch inch ft in2 ft2 ft/sec ft/sec2

Log Mean Temperature Difference Temperature Difference at Hot End Temperature Difference at Cold End LMTD

∆T 1 ∆T2 ∆TLM

CORRECTION FACTOR (F) R S

3.714285714 0.212121212

130 35 72.39825135

F

Corrected LMTD

0.87 (FROM GRAPH)

62.98647867

CALORIFIC TEMPERATURE

∆Tc/∆TH

0.269230769

FC WALL TEMPERATURE

HEAT TRANSFER SURFACE

0.28

102.7908355 640.7232

TUBE SIDE CALCULATION PARAMETERS

Flow area Mass Velocity Reynolds Number Factor for Heat Transfer Prandtl Number hi/φt hio/φt μ at wall temperature Viscosity Ratio Heat Transfer Coefficient

UNIT ft2 2

lb/(hr)(ft ) lb/(ft)(hr) Btu/hr

NOTATION at GT Re JH Pr μw φt hio

VALUES

0.106958333 776483.9446 22118.02751 76 5.020746888 909.956839 752.7162972 1.573 1.020236148 767.9483756

TUBE SIDE 0.00027 3.783963561 1.947826087 5.731789648