Fractionation Column Calculation

8/13/2019 Fractionation Column Calculation

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SIZING COLUMN DISTILATION (based on GPSA - Detailed Method)

INPUT DATA5.06 lb/ft3

Vapor Mass rate 10460.00 lb/hr

Vapor Vol. rate 2065.97 ft3/hr

47.31 gpmLiquid density 24.14 lb/ft3

Liquid surface tension, 1.399 dyne/cm

12 inch

CALCULATION

A Calculate System Factor based on Fig. 19.15

system factor 0.72

Vapor Density

Liquid rate

tray spacing,


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B Calculate the downcomer velocity (VDdsg) based on Fig. 19-16

Tray spacing 12 inch

rL - rV 19.077 lb/ft3

VD*dsg 115 gpm/ft2

VDdsg= VD*dsg x system factor82.81 gpm/ft2

C Calculate the vapor capacity factor (CAF) based on Fig. 19.17

rV 5.063 lb/ft3

tray spacing 12 inch


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CAFo 0.27 ft/s

CAF= CAFo x system factor

0.19 ft/s

C Calculate the tray active area (AAM)

Vload 0.30 ft3/s NP 1

Dt 2

GPM 47.308387 gpm FPL 18

CAF 0.19 ft/s

FF 0.82 Flooding Factor (commonly used is 0.82 for most syste

AAM 2.27 ft2

D Calculate the tray downcomer area (ADM)

ADM 0.70 ft2 ok


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Check: if ADM is less than 11% of AAM, use 11% of AAM or double ADM, whicever is small

11% AAM 0.25 ft2

E Calculate the diameter of column (Dt)

ATM (1) 3.66 ft2 ATM (2) 2.38 ft2

Dt (1) 2.16 ft Dt (2) 1.74 ft

Dt selected 2.16 ft

F Height of Column Required (H)

21 HYSYS

Tray Efficiency 80% Assumption

Actual Tray 26

25

Tray Spacing 1.00 ft

Top Section 5 ft Commonly 5-10 ft is sufficie

Bottom Section 4 ft

34.25 ft

RESULT PARAMETER result

ID 2.16 ft= 660 mm H/ID 16

H 34.25 ft= 10450 mm H 34

G Nozzle Sizing

LocationMass Rate,

lb/hrDensity,lb/ft3

Vol. Rate,

ft3/h ID Pipe, inch

Actual

Velocity, ft/s

Actual rho-

v2

Feed Inlet 3715.07 9.217708572 403 2 1.75 28

Liquid Outlet 11940.326 24.39749223 489 2 2.12 110

Vapor Outlet 4803.2009 3.199174364 1501 2 6.50 135

Reflux Inlet 2886.5702 28.60986633 101 2 0.44 5Reboiler Inlet 10141.886 5.145151558 1971 2 8.54 375

H Bottom Level Setting

Interval Level, inch

Total Volume,

ft3

Hold-up

Time, minin. Level, inc

Min. Hold-up

Time, minCriteria

LLLL-BOV 12 43.91 7 12 OK

LLL-LLLL 6 21.95 3 6 1 OK

Theoritical Tray

space inter Tray

Heigh of Column


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NLL-LLL 6 21.95 3

HLL-NLL 6 21.95 3

HHLL-HLL 6 21.95 3 6 1 OK

Total 36

Min. height of bottom sectio 3 ft

12 3 OK


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Hysys

Hysys

HysysHysys

Hysys

Assumption


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pass tray assumption

ft Fig. 19.14

ft

m)


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r.

t for disengaging purpose

Criteria

max. 20

175

.

Velocity,Max. rho-

v2Criteria

4000 OK

3 OK

60 2500 OK

4000 OK4000 OK


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Fractionation Column Calculation