sub group 43

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Process Flow diagram

Fig : Process Flow sheet Made with help of ASPEN PLUS

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Equipment Designed

1. Compressor2. Pump

3. Reactor

4. Gas Absorber

5. Crude Fractionating Column

6. Refining Column

7. Effluent Column

8. End stripping Column

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Compressor Design Positive Displacement Reciprocating

compressor

Multi Stage.Assumptions:

- Zero clearance

Volume Swept in compressor

n = No. of cylinder Fig:- Interior of reciprocating Compressor

N = rotational speed

D = dia/bore of the cylinderL = Stroke length

[1]

PB= power consumed by compressor

Fig: Gas Compression Cycle1 References: mccabe smith unit o eration of chemical en ineerin 7th edition 7th cha ter a e 221

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Calculated Data

[1] References: COMPRESSOR HANDBOOK Paul C. Hanlon 2001 Chapter 2 compressorperformance - positive displacemnt by

The McGraw-Hill Companies

AIM : To compress the CO coming from Sub group 1 Inter Stage Cooling Assuming Temperature rise in water (T) = 20oc Coolant Used :water Power = 165.56 kw = 221 hp Fig: water cooling system No. of stage = 3 Compression ratio R(total) = 41.95 Heat load in each cooler = 49,570.834 kJ/hr Total heat load = 3*49,570.834 = 148712.50 KJ/hr Amount of water required = 1770.38 Kg/hr

Pressure Temperature Flow Rate

Inlet condition 1 atm 373 k 0.024 m3/sec

Outlet Condition 42 atm 453 k

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RPM calculation

bore/stroke ratio < 1.7. [1]

No. of Cylinders Stroke length and bore diameter Maximum Volume occupied in each

cylinders.

Table : Calculation of RPM, bore length, piston speed, volume of each cylinder[2]

References :

[1] Stroke-to-Bore Ratio: A Key to Engine Efficiency by Dr. Randy Herold Engineer General Atomics Systems[2] ''Large reciprocating Compressor Design Guide Lines''(1972) M.W Garland Frick Company, International Compressor Engineering

Conference

Design Data

RPM 720

No. of cylinder

(each stage)

2

Bore/ Stroke 1.35

Stroke 5.00

Bore 6.75

volume of each

cylinder per

revolution

24.48 cu inch

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Fig: Schematic Diagram for Pump design

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Requirements for adiabatic Pump

Specific volume = 1262 cm3/ kg

Thermal Expansion Coefficient() = 425 x 10-6K-1

Specific Heat capacity = 2.74 KJ/kg k

Assuming

Pump Efficiency = 75 %

equations used for pump :

Ws(isentropic)=V (P2-P1)=Hs ----------- (i)Hs=Ws ------------ (ii)

Hs = CpdT+ V(1-T)P[1] ----------- (ii)

Using equation (i) (ii) and (iii)

we get Ws= 5.24kJ/kg Hs = 6.98 kJ/kg,

and temperature rise to be 2.5 0 c , So final temperature is 57.540 c and pressure is 42 atm out of adiabatic

pump of 9.67 hp

Pressure inlet 1 atm

Temperature 55 c

Mass flow rate 1.034kg/sec

Pressure Inlet 42 atm

Temprature 57.54 c

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Centrifugal Pump

Density of

methanol

791.8 kg/m3

Flow rate 30 gpm , 1.8

kg/ sec

Presuure 1 atm

Temperature 55 0C

RPM 1900

Suction head

loss

0.469 m of

methanol

Total

dynamic

head

13.62 m =

44.7 feet of

methanol

WHP 0.6 hp

BHP(with eff.

0.75)

0.8 hp

Length of

pipe

50 m

Friction factor 0.0193

Total

frictional

head loss

0.78 m of

methanol

Diameter of

pipe(standar

d stainlesssteel)

1.0 in

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Reactor Design

FAo (molar flow rate of

methanol)

132948 mol/hr

X (conversion of methanol) 0.98

(-rmethanol)exit 30.3 mol/ gcat-hr

W (weight of catalyst inreactor)

1.225 kg

Bulk density of catalyst 12410 kg /m3

Volume of catalyst in reactor 9.87 x 10-5m3

Volume of slurry in thereactor with s=0.3

3.29 x 10-4m3

Diameter of tank with

(L/D=5)

2.57 m

Height of the reactor 13 m

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Bubble specifications

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Gas Absorber

Gases Volume (gmol) % volume

CO 3545 23.66

CO2 360 2.40

CH4 75 0.50

HI 60 0.40

CH3I 10940 73.03

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Assumptions

gas and liquid streams flow through the

absorber not change appreciably

90% reduction of CH3I from Inlet

concentration

75% Flooding Velocity

Stream Flow rate = 1.77m3/min

Temp = 328K and pressure = 1atm

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Calculation for Tower Diameter

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Calculation for Tower height

Z = Height

HTU = height of transfer

unit

NTU no of transer unit

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Final Data for absorber

Diameter 1.6m

Height 5.1m

Area 2.24m2

Number of Transfer units 2.43

Gas flow rate 68.35 g-mol /min

Liquid Flow rate 2187.5 gmol/min

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Packing Data

Packing used here is Intalox saddles (plastic)

Size - 2in

Weight - 38(lb/ft2)

Surface area/packing volume - 36 ft2/ft3

VOid Fraction - 79%

Packing factor - 40ft2

/ft3

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Crude Fractionating Column

Extractive Distillation:No azeotropic

High Boiling

Low relative volatility

Fig#1 C 301 Crude Fractionating Column

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Designing:

Column Diar

References: Coulson and Richardson: Volume 6, Tamkang Journal of Science and Engineering, Vol. 4, No. 2, pp. 105-110 (2001)

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HydraulicsColumn Diameter

Fair Correlation

Total Column Area: Ac= An+ Ad

Liquid Flow

Arrangement

Cross Flow

Active area Aa=Ac-2Ad

Weir length Ad / Ac

Plate DesigningMinimum Vapor

Velocity

Crest Depth how=750[(Lm/lw*)2/3]

Check Weeping

References: Coulson and Richardson: Volume 6, Tamkang Journal of Science and Engineering, Vol. 4, No. 2, pp. 105-110 (2001)

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Dry Plate Drop

Total Pressure Drop

DowncomerBack-up

hb= (hw+ how) + ht+ hdc

Head Loss

Residence Time: tr=AdhbcL/L(max)

Entrainment: Fractional entrainment ()

Number of Holes: Area of 1 Hole = (/4)

Dhole2

Pressure Drop

Downcomer

Liquid Backup

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Design Data

No. of trays 68

Pressure 101.325 kpa

Height of column 35m

Diameter of column 1.45m

Hole size 5mm

Pressure drop per

tray

1.2kpa

Tray thickness 5mm

Vapour Flow Ratelbmol/hr

331 lb mol/hr

Downcomer liquid backup 0.20mm

Actual minimum Vapor

Velocity

12.81 m/sec

Active holes 5900

Weir Height 50mm

Weir Length 1m

Reflux Ratio 6.23

Tray Spacing 0.5m

Active Area 1.16 m2

Percentage

Flooding

85%

Entrainment 0.075

Liquid Flow rate 880 lbmol/hr

Residence time 10 sec

MIn. Designing

Vapor Velocity

9m/sec

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Refining Column

Refining column mass balanceTotal Distillate Rate =2Kg/sec

Compound Mass Flow Rate

(Kg/sec)

Mole Flow Rate

(KMol/sec)

Mole Fraction

(Percentage)

Acetic acid 1.97 3.28 x 10-2 98.73

Propionic Acid 0.03 4.21 x 10-4 1.27

Feed Flow Rate =2.29 Kg/sec

Acetic Acid 2.22 3.28 x 10-2 97.75

Propionic Acid 0.07 9.49 x 10-4 2.25

Bottom Flow Rate =0.29 Kg/sec

Acetic Acid 0.25 3.28 x 10-2 86.45

Propionic Acid 0.04 4.42 x 10-4 13.54

Design and optimization of a dividing wall column for debottlenecking of the acetic acid purification process

By:-Nguyen Van Duc Long, Seunghyun Lee, Moonyong Lee Chemical Engineering and Processing 49 (2010)

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Temperature inside

the column=400 K

Pressure=100 Kpa

Column Height

Ideal No. of tray 4

Actual no. of tray 6

Tray spacing 0.5 m

Column height 3 m

Mass transfer operation By:-Robert E. Treybal Third Edition

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Column Diameter

Gas density G1.81 Kg/m3

Vapor rate Q 1.01 m3/sec

Liquid density L725.175 Kg/m3

Liquid flow rate 4.21 10-4m3/sec

Hole diameter 3 mm

plate thickness(0.65 *Hole

area)

1.95 mm

Pitch ( P'=hole diameter/0.33) 9.09 mm

Downspout area

Hole area/Activearea=0.907x(d0/l)2

98.79 10-3


http://profmaster.blogspot.in/2007/06/surface-tension.html(surface tension)

Fluid Phase Equilibria 54 (1990) Masahiro kato, Hiroshi yoshikawa and Yamaguchi Dustrial chemistry

department of faculty of engineering Nihon University Koriyama Fukushima Japan
http://profmaster.blogspot.in/2007/06/surface-tension.htmlhttp://profmaster.blogspot.in/2007/06/surface-tension.htmlhttp://profmaster.blogspot.in/2007/06/surface-tension.htmlhttp://profmaster.blogspot.in/2007/06/surface-tension.html

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Weir Crest h1and weir height hw

q/Weff=1.8939 h13/2

When taking W= Weff h1=5.78 10-3m

Weff = 0.9656 W

again

=5.89 10-3m

Repeat with new value of h1 Weff= 0.9649 W so h1=58.94 10-4m Set weir height hw= 0.012 m

Net tower cross section area of gas

flow Anf=Q/V

0.68 m2

Tower cross-sectional area At=An/(1-

downspout)

0.711 m2

Tower Diameter T=[(4At)/]0.5 95.15 x 10-2 m

Weir length W =0.55T 52.33 10-2m

Liquid rate /weir length (q/W) 8.04 10-4 m2/m-s

Active area 53.59 10-2 m2

for perforated sheet


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Because h1+ hw+ h3< t/2 so my assuming tray spacing (0.50) its perfectly satisfied

Weeping will not occur till velocity through orifice reduce to weeping velocity

Dry Pressure Drop 4.62 10-2m

Hydraulic Head HL 8.25 10-3m

Residual Pressure Drop 8.85 10-4m

Total gas pressure drop 5.938 10-2m

Tray pressure drop 0.00256 psi or 17.650547 Pa

Pressure loss at liquid

entrance

0.56 10-2m

Ada 0.31 10-2m

Backup in downspout 6.4 10-2m

Checking on flooding =81.89 10-2m

Weeping Velocity 0.068 m/sec

Weir set = 0.418 T 0.3978

Z=2 Times weir set 79.56 10-2m

Entrainment 0.0035


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Tray Performance Constraints

1.Foaming:-It's depend on material property.

2. Entrainment:-The entrainment is too small to influencethe tray hydraulics appreciably.

3.Flooding:-flooding will not occur until velocity V isincrease above flooding velocity.

4.Weeping:-The tray will not weeping excessively until thegas velocity through the hole Vois reduced to close thisvalue.

5. Downcomer flooding:it's happened when liquid rate ishigh and vapor flow rate is less.

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End Stripping Column

Plate or Packed Column:

Packed column was selected for the reasons given below: Good liquid distribution can be maintained throughout

Economic to replace packings than trays in case of fouling

Since the liquid is corrosive hence packed column is relatively cheaper

Liquid holdup is comparatively lower in packed columns. Important in caseof flammable inventory

More suitable for handling foaming systems

Relatively lower pressure drop

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Choice of Packing:

Random packing of 0.038m

ceramic intalox saddle has

been chosen for the followingreasons:

One of the most efficient

packings

Little tendency to nest and

block areas of bed

Gives a fairly uniform bed

Higher flooding point

Lower pressure drop

Packing Details

Packing Factor 52

Dry Bed Packing

Factor

50

Mass 624 kg/m3

Surface Area 195 m2/m3

Voidage 76%

Min. Wetting Rate 3.4x10-6m2/s

Material Balance:

D i C l l ti

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Design Calculations:

Harriott, P. Chemical Reactor Design. New York: Marcel Dekker, 2003; Chapter 8

Carl R. Branan. Rule of Thumbs for Chemical Engineers, 4th ed. Butterworth-Heinemann, 2005; p. 109-113; p.143-

152Perry, R.H., and D.W. Green. Perrys Chemical Engineers Handbook, 7th ed. New York: McGraw-Hill, 1997; p. 15-86

Parameter and Equations Calculated Value

1 Height Equivalent of Theroretical Plate

(HETP)

0.035 m

2 Number of Transfer Units 5

3 Height of overall Gas Transfer Units 1.45

4 Column Height:

HTotal= HOGx NTotal

7.78 m

5 Diameter of Column: 0.83 m

M h i l D i

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Mechanical Design:

Parameter and Equations Calculated Value

1 Thickness of Shell (ts): 30.8 mm

2 Shell Weight (W):

W= Vol. of Shell x Density of Material

9670 kg

3 Head Selection and Thickness (th): 32 mm

4 Head Weight (Wh): 58 kg

Gavin Towler, R.K. Sinnott. Chemical Engineering Design: Principles, Practice and Economics of Plant and Process

Design, 2nd ed. Butterworth-Heinemann, 2013; p. 279-302; p. 807-923

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Heat ExchangerPreliminary calculations

Procedure for estimating area

Shell side Q= W*C*dT

Q=4254.34*0.64*(180-57)

Q=334901644.8 cal = 1402166.206449 KJ = 1.402 * 106 KJ

LMTD = (T1-t2)-(T2-t1)/(ln(T1-t2)/(T2-t1))

=((198-180)(108-57.546))/ln((198-108)/(108-57.546))

=48.88 deg C

Assumed data: Di = 1.049 inches = 0.0874 ftDO = 1.315 inches = 0.1096 ft

XW = 0.133 inches = 0.0111 ft

Methanol coefficient = 1020

Water = 1700

Inside Fouling Factor = 5680

Outside Fouling Factor = 2840

DL = (DODI)/(ln(Do/DI)) = (0.10960.0874) / (ln(0.1096/0.0874)) = 0.0983 ft

Overall coefficient, UO = 459 W/m2 deg C

Total outside heat transfer area, Ao = Q/Uo*LMTD

= 1402166.20/(459 * 48.88)

=62.49 sq m

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Pinch Design Method

Stream no Stream type Het capacityFlow rate

Source

temperature

Target

temperature

1Hot 6 200 65

2 Hot 3 90 30

3 Cold 3.5 57.5(temp from

the absorber)

180(final temp as

reqd in the

reactor)

4 Cold 4 25 130

Reference :

B. LINNHOFF and E. HINDMARSH

THE PINCH DESIGN METHOD FOR HEAT EXCHANGER NETWORKS

Department of Chemical Engineering, University of Manchester Institute of Science and TechnologyChemical Engineering Science Vol. 38, No 5 pp 745-763, 1983

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Hot End Design

Design 1 Design 2

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Cold End Design

Design 1 Design 2

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Liquid effluent column

absorbent - CaO 75%-MgO 25%

Mass of absorbent 1.31 kg

L/D 1.75

porosity 0.4

Diameter of spehrical particle 1um

Diameter 5.5

Height of tower 9.625

total No. of particle 771*10 18

total no. of particle in 1 layer 96.35 *10 12

height of absorbent bed 8m

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Storage of acetic acidL/D ratio ?

Design and construction of tank

Stainless steel grade 304 ,316,314

High density polyethene

.propylene and rubber lined carbon steel

hydrostatic gauge fabricated with stainless steel of suitable grade

gauge glass covered from all sides (especially for 80% acetic acid).self- priming centrifugal pumps mechanically sealed with PTFE wedges

pvc or polypropylene ball valves

earthing should be provided

The fitting of low and high temperature alarms

ACETIC ACIDCORROSIVE TO SKIN

Emergency instructions, in case of splashing

eye baths or wash bottles containing water

Buckets of sodium bicarbonate

i

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Storage of raw material (methanol)

Design and construction of tankcarbon steel with interior surface coated with epoxy resin.

side ways agitator according to API-650

volume of raw material 113597m3

L/D 0.5

diameter 13.65m

height 6.825m

no. of tanks 14

sub group 43

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