Table of contentTable of content

1- Heat exchanger design (cooler )1- Heat exchanger design (cooler )

22 - -Distillation column designDistillation column design..

33 - -ValveValve..

Heat Exchanger DesignHeat Exchanger Design

ObjectivesObjectives::

E102 - To decrease temperature E102 - To decrease temperature of stream which exit from R-100. of stream which exit from R-100.

E103 - To decrease temperature E103 - To decrease temperature of stream which exit from E102.of stream which exit from E102.

AssumptionsAssumptions::

11. Assume the water inter in tube side.. Assume the water inter in tube side.

2.2. Use shell and tube heat exchanger.Use shell and tube heat exchanger.

3. Shell and tube heat exchanger counter flow is used 3. Shell and tube heat exchanger counter flow is used because it is more efficient than the parallel flow.because it is more efficient than the parallel flow.

4. The value of the overall heat transfer coefficient was 4. The value of the overall heat transfer coefficient was

assumed based on the fluid assigned in both sides.assumed based on the fluid assigned in both sides.

5.The outer, the inner diameter , the length of the tube, 5.The outer, the inner diameter , the length of the tube, and the number of passes were assumed.and the number of passes were assumed.

For a good designFor a good design: :

1.1. The assumed overall heat coefficient has to be equaled to The assumed overall heat coefficient has to be equaled to the calculated overall heat transfer coefficient.the calculated overall heat transfer coefficient.

2. The pressure drop in the tube side has to be lower than 1 2. The pressure drop in the tube side has to be lower than 1 bar.bar.

3. The pressure drop in the shell side has to be lower than 1 3. The pressure drop in the shell side has to be lower than 1 bar. bar.

Design procedure of Heat Exchanger

1.Define the duty: heat transfer rate, fluid flow rates, temperature.2.Collect together the fluid physical properties required: density,

viscosity,Thermal conductivity.3.Select a trail value for the overall coefficient, U.

4.Calculate the mean temperature difference, ΔTm.5.Calculate the area required from Q=UAΔTm.

6.Calculate the bundle and shell diameter7.Calculate the individual coefficients.

8.Calculate the overall coefficient and compare with the trail value.9.Calculate the exchanger pressure drop.

10.Calculate thickness of the shell.

11.Find the price of the heat exchanger based on the heat transfer

area and the material of construction

Calculation procedure of shell and tube heat exchanger:

1. Heat load ,(kW)

2 .Log mean Temperature, (˚C)

Where -T1T1 : Inlet shell side fluid temperature (˚C).

- T2T2 : Outlet shell side fluid temperature (˚C).

- t1t1 : Inlet tube side temperature (˚C).

- t2t2 : Outlet tube temperature (˚C).

TmCQ ph

)(

)(ln

)()(

12

21

1221

tT

tTtTtT

Tlm

3.Provisional Area, (m2)

Where:

- True temperature difference.

- Temperature correction factor

Where:Where:FFtt: is the temperature correction factor: is the temperature correction factorR: is the shell side flow *specific heat / tube side R: is the shell side flow *specific heat / tube side

flow*specific heat, (Dimensionless).flow*specific heat, (Dimensionless).S: is temperature efficiency of the heat exchanger, S: is temperature efficiency of the heat exchanger,

(dimensionless)(dimensionless)

mTU

QA

)1(1(2

)1(1(2)1(

)1(

)1()1(

2

2

2

RRS

RRSLNR

RS

SLNR

Ft

)(

)(

12

21

tt

TTR

)(

)(

11

12

tT

ttS

mT

lmtm TFT tF

4. Area of one tube, m2.

Where:

-do : Outer diameter (mm)

-L : Length of tube (mm)

-Number of tubes = provisional area / area of one tube

LdA o

5 .Overall heat transfer coefficient, W/m2 oC.

Where:

- Outside coefficient (fouling factor). -Inside coefficient (fouling factor).

6 .Bundle diameter .

Where:

-Db: Outside diameter (mm).

-Nt: Number of tubes.

-K1 & n1 are constant.

ii

o

id

oi

o

odo hd

d

hdi

d

kw

d

dLNd

hhU

11

2

1110

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odh

idh

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1

n

tob K

NdD

7 .Shell diameter.

8 .Shell thickness.

Where:

-t: shell thickness (in).

-P: internal pressure (psig).

-ri: internal radius of shell (in).

-EJ: efficiency of joints.

-S: working stress (psi).

-Cc: allowance for corrosion (in).

ClearanceDD bs

cJ

i CPSE

t

6.0

Pr

9-Pressure drop9-Pressure dropTube side:Tube side:

Where:

ΔPt: tube side pressure drop (N/m2= pa)

Np : number of tube side passesu : tube side velocity (m/s)L: length of one tube, (m)

Shell sideShell sideLinear velocity = Gs /р

Where:L: tube length, (m)

lb: baffle spacing (m)

Use fig.(12.30) to get jf.

2

25.2

/

/8

u

MM

dLjNP

w

ifpt

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Equipment NameEquipment NameHeat exchanger Heat exchanger

ObjectiveObjectiveTo cool the mixture of To cool the mixture of

Ethanol ,Methanol ,Propanol ,water and Ethanol ,Methanol ,Propanol ,water and syn-gas using cooled water syn-gas using cooled water

Equipment NumberEquipment NumberE-102E-102

DesignerDesignerNoura Manahi Noura Manahi

TypeTypeShell and tube heat exchangerShell and tube heat exchanger

LocationLocationAfter Reactor R-101 After Reactor R-101

UtilityUtilityCooled waterCooled water

Material of ConstructionMaterial of ConstructionCarbon steelCarbon steel

InsulationInsulationQuartz wool – Glass woolQuartz wool – Glass wool

Cost ($)Cost ($)$218500 $218500

Operating ConditionOperating Condition

Shell SideShell Side

Inlet temperature (Inlet temperature (ooC)C)320 320 Outlet temperature Outlet temperature

((ooC)C)187.8 187.8

Tube SideTube Side

Inlet temperature (Inlet temperature (ooC)C)2525 Outlet temperature (Outlet temperature (ooC)C)197.8 197.8

Number of Tube RowsNumber of Tube Rows22Number of TubesNumber of Tubes3369 3369

Tube bundle Diameter (m)Tube bundle Diameter (m)4.46733 4.46733 Shell Diameter (m)Shell Diameter (m)4.5463 4.5463

Q Q totaltotal (Kw) (Kw)1127611276.4243 .4243 LMTD (LMTD (ooC)C)141141.530 .530

U (W/mU (W/m2 o2 oC)C)85 85 Heat Exchanger Area Heat Exchanger Area

(m(m22))1143.007904 1143.007904

Equipment NameEquipment NameCoolerCooler

ObjectiveObjectiveTo cool the mixture of To cool the mixture of

Ethanol ,Methanol ,Propanol ,water and Ethanol ,Methanol ,Propanol ,water and syn-gas using cooled water.syn-gas using cooled water.

Equipment NumberEquipment NumberE-103E-103

DesignerDesignerNoura Manahi Noura Manahi

TypeTypeShell and tube heat exchangerShell and tube heat exchanger

LocationLocationAfter Heat ExchangerAfter Heat Exchanger

UtilityUtilityCooled waterCooled water

Material of ConstructionMaterial of ConstructionCarbon steelCarbon steel

InsulationInsulationQuartz wool – Quartz wool – GlassGlass wool wool

Cost ($)Cost ($)$142300$142300

Operating ConditionOperating Condition

Shell SideShell Side

Inlet temperature (Inlet temperature (ooC)C)187.8187.8 Outlet temperature Outlet temperature ((ooC)C)

60 60

Tube SideTube Side

Inlet temperature (Inlet temperature (ooC)C)2525 Outlet temperature (oC)Outlet temperature (oC)95 95

Number of Tube RowsNumber of Tube Rows22 Number of TubesNumber of Tubes16131613

Tube bundle Diameter (m)Tube bundle Diameter (m)22.666.666 Shell Diameter (m)Shell Diameter (m)27282728

Q Q totaltotal (Kw) (Kw)18772.43018772.430 LMTD (oC)LMTD (oC)59.27606 59.27606

U (W/mU (W/m2 o2 oC)C)560560 Heat Exchanger Area Heat Exchanger Area (m2)(m2)608.0932 608.0932

Distillation ColumnT-(102) designDistillation ColumnT-(102) design

• Objective :

- To separate water from a mixture of ethanol and propanol.

• Assumptions:1.Tray column.2. Sieve plate.3. Material of the distillation is carbon steel.4. Plate spacing= 0.55 m5. Efficiency = 75%6. Flooding % = 85%7. Weir height = 50 mm8. Hole diameter = 5 mm9. Plate thickness =5 mm

Good Design:

1.No weeping.2.Down comer back up is less than

half ( plate thickness+ weir height).

3.No entrainment.4.Calculated percentage flooding

equal to the assumed one.5.Residence time exceeds 3 secs.

Design procedure of Distillation Column

1. Specify the properties of outlets streams: (flow rate, density and surface tension) for both vapor and liquid from HYSYS.

2. Calculate the maximum liquid and vapor outlet flow rate.3. Choose tray spacing and then determine K1 and K2 .4.Calculate correction factor for Bottom K1 and Top K1.5. Design for X% flooding at maximum flow rate for top and bottom part of distillation.6. Calculate the maximum flow rates of liquid.7. Calculate Net area required.8. Take down comer area as %Y of the total column Cross

sectional area.9. Calculate the column diameter.10. Calculate the column height using the actual number of

stage.

11. Calculate column area, down comer area, active area, net

area, hole area and weir length.

12. Calculate the actual min vapor velocity.

13. Calculate Back-up in down comer.

14. Check residence time.

15. Check entrainment.

16. Calculate number of holes.

17. Calculate area of condenser and reboiler.

18. Calculate Thickness of the distillation.

19. Calculate cost.

Calculation procedure of Distillation Column

• For column diameter

1-Calculate the liquid –vapors flow factor for top and bottomFLV= LW / Vw * (ρv / ρl) ½

Where:

• LW = liquid mole flow rate in kmol /h

• Vw = vapors mole flow rate in kmol / h

• ρv = density of the vapors in kg / m³

• ρl = density of the liquid in kg / m³

2-From fig 11.27 get constant for the top and the bottom top k1 and bottom k1

3-Calculate the correction factor for top and the bottomK = (σ / 0.02) ^0.2 * K1

σ = liquid surface tension in N/m

4-calculate the flooding velocity for top and bottomUf = K *( (ρl –ρV) / ρ v)½

Where:

• Uf = flooding vapor velocity in m/s

• K= constant obtain from fig (11.27)

• ρl = density of liquid in kg / m³

• ρv = density of vapour in kg / m³

5-Assume the flooding percentage is 85% at max flow rate for the top and the bottom

UV = 0.85 * Uf

6-Calculate the net area for the top and the bottom

An = V / UVWhere:

• An = net area in m²

• V = Volumetric flow rate in m³ / s

• UV = vapour velocity in m/s

7-Assume as first - trail take down comer as 12% of total cross sectional area

for the top and the bottomAd = An / 0.88

Where:Ad = area of the down comer in m²

An = net area in m²

8-Calculate the diameter for the top and the bottomD = ((4 /3.14) * Ad) ½

Where:D = Diameter in m Ad = area of the down comer in m²

9-calculate the liquid flow pattern

Max liquid volumetric flow rate = Lm *MW / ρL * 3600

10-Calculate the areasAc = (3.14 / 4)*D²

• Where: Ac = total cross sectional area in m²

Ad = 0.12 * Ac

• Where: Ad = area of the down comer in m²

An = Ac –Ad

• Where: An = net area in m²

Aa = Ac – 2Ad

• Where: Aa = active area in m²

Ah = 0.1 * Aa

• Where:Ah = hole area in m²

11-Use fig 11.31 to get LW / D

12-Assume:weir length = 50 mm

Hole diameter = 5 mm

Plate thickness = 5 mm

13-Check weeping how max = 750 * (Lwd/ (Ad*ρl)) ^2/3

how min = 750 * (Lwd/ (LW*ρl)) ^2/3

At min rate = hw + how

Where:how=Weir liquid crest

14-Calculate the weep pointUh = k2- 0.9 *(25.4-dh)/ρv½

Where:Uh = min vapor velocity through the hole in m/s

Dh = hole diameter in m

K2 = constant from fig 11.30

15-Calculate the actual vapor velocity

Calculate the actual vapor velocity = min vapor rate / Ah

It should be above weep point

16-Calculate the pressure drop

UH = Vv / Ah

• Where:

Vv = volumetric flow rate in m³ / s

»Ah = net area in m²

Hd = 51 * (Uh/ C0)² * ρV / ρL

• Where:

Hd = dry plate drop

Uh = min vapor velocity in m/s

C0= 0.84

Continue of calculating the pressure drop

Hr = 12.5E3 / ρL

• Where:

Hr = residual head

Ht = HD + HW + HOW + HR

• Where:

Ht = total pressure drop in mm

17- down comer liquid backup

Hap = Hw – 10

• Where:

Hw= Weir height

Aap = LW * hap *0.001• Where:

Aap = area of apron

Hdc = 166 * LW / (ρ l * Aap)

Backup down comer Hb = hdc + ht + how max + hw

18- Calculate the residence time TR = (Ad * hb * ρ l) / lwd

TR should be >3 s

19-Calculate the flooding percentage Flooding percentage = Uv / Uf * 100

20- Calculate the area of one hole

A = (3.14 / 4 ) * (dh * 0.001 )²

Where:

dh is hole diameter.

21- Calculate number of holes

Number of hole = A h / A

22- Calculate the thickness

Where:t: thickness of the separator in (in)P: operating pressure in Pisari: radius of the separator in (in)S: is the stress value of carbon steel = 13700 PisaEj: joint efficiency (Ej=0.85 for spot examined welding)C0: corrosion allowance = 0.125

23- calculate the cost

Pr

0.6i

oj

t CSE P

Equipment NameDistillation Column

ObjectiveTo separate water from a mixture of

ethanol and propanol .

Equipment NumberT-102

DesignerNoura Manahi

Type Tray column

LocationSeperation section

Material of ConstructionCarbon Steel

InsulationMinral wool and glass fiber

Cost($) 4141505

Column Flow Rates

Feed (kgmole/hr)1321 Recycle (kgmole/hr)-

Distillate (kgmole/hr)110.1 Bottoms (kgmole/hr)1211

Key Components

LightEthanol HeavyWater

Dimensions

Diameter (m)2.7 Height (m)15.2

Number of Trays17 Reflux Ratio12

Tray Spacing0.55Type of traySieve trays

Number of Holes978

Cost

Vessel$137,300Trays$1600

Condenser Unit$23,300Reboiler$202,000

Valve:

Objective:

To decrease the pressure.

Assumptions:

• Gate valve.

• The diameter is 5 in.

Equipment NameValve

ObjectiveTo decrease the pressure

Equipment NumberVLV-100

DesignerNoura AL-Dosari

TypeGate Valve

LocationAfter V-100

Material of ConstructionQuartz wool

Cost$1,500

Operating Condition

Inlet Temperature (oC)60 Outlet

Temperature (oC)

58.88

Inlet Pressure (psia)869.6 Outlet Pressure

(psia)30