Equipment DesignDesigned by Eman A. Khajah

Outline• Design of Heater.• Design of Stripper.

Heater Design• Construction of Shell and Tube Heat Exchanger.

Objective• To heat up the streams before entering the

reactors.• To heat up the propane stream before

recycle it back to the feed.

Assumptions

• Counter current flow heat exchanger to provide more effective heat transfer.

• Assume the value of the overall heat transfer coefficient.

• Assume the outer, the inner diameter and the length of the tube on both the Shell and tube sides.

Design Procedure

• Calculate the duty or heat load.

Where,

m: mass flow rate, kg/hr

Cp: specific heat, kJ/kg°C

∆T: temperature difference, °C• Collect physical properties.

coldphotp TmCTmCQ

• Assume U : overall heat transfer coefficient, W/m2oC.• Calculate heat transfer area required.

Where,

Tm = Ft Tlm.

∆Tlm : log mean temperature difference.

T1 : inlet shell side fluid temperature.

T2 : outlet shell side temperature fluid temperature.

t1 : inlet tube side fluid temperature .

t2 : outlet tube side fluid temperature.

mo TU

QA

12

21

1221

lntT

tTtTtT

Tlm

• Choose tube size and material, then calculate number of tubes required.

• Calculate Ds : shell diameter.

• Estimate tube side heat transfer coefficient hi, W/m2°C.

• Choose Lb : baffle spacing.

• Calculate area of cross flow.

• Estimate shell side heat transfer coefficient ho, W/m2°C.

• Calculate U overall heat transfer coefficient using:

Where,Uo: overall coefficient based on outside area of the tube (W/m2oC).ho: outside fluid film coefficient (W/m2oC).hi : inside fluid film coefficient (W/m2oC ).hod : outside dirt coefficient (fouling factor) (W/m2oC).hid : inside dirt coefficient (fouling factor) (W/m2oC).kw : thermal conductivity of the wall material (W/m2oC ).di : tube inside diameter.do: tube outside diameter.

SdSw

i

oo

i

o

idio hhk

d

dd

d

d

hhU

11

2

ln111

• Estimate tube and shell side pressure drop.• Calculate shell thickness.

Where,P: design pressure, psia R: inside radius of shell, inchS: maximum allowable stress value, psiaE: the joint efficiency C: corrosion allowance• Select a material of construction and insulation.• Calculate cost.

CPSE

PRt

6.0

Results Equipment Heater E-102

Type Shell and tube heat exchanger

Material of construction Carbon Steel

Qtotal (kW) 11943.699

U(W/m² °C) 30

Inlet temperture, Shell side °C 327

Oultlet, Shell side °C 550

Inlet temperature, Tube side °C 600

Outlet temperature, Tube side °C 100

Number of tubes 5593

Shell diameter, m 1.56

LMTD, °C 155.6

Heat exchanger area, m² 2558.21

Insulation Glass wool

Cost, $ 77,300 $

Stripper Design

• Construction of stripper.

Objective• To separate CO2 from water and get a

stream of pure CO2.

Assumptions• Tray spacing= 0.75.• Efficiency= 75%.• Percent of flooding at maximum flow rate=85%.• Percent of downcomer area of total area=12%.• Percent of hole area of active area=10%.• Weir height=50 mm.• Hole diameter=5 mm.• Plate thickness=5 mm.

Design Procedure• Collect, or estimate, the system physical properties.• Calculate liquid vapor flow rate.

Where:

FLV= liquid vapor flow rate.

L= liquid flow rate.

V= vapor flow rate.

5.0

L

vLV V

LF

• Calculate the flooding velocity

Where:Uf= flooding velocity.K1= constant.

• Calculate the actual velocity.

Where:Uv= actual velocity.

5.0

1

)(

V

VLf KU

fV UxFloodingPercentageU

• Calculate the maximum volumetric flow rate.

Where:

Vmax= maximum volumetric flow rate.

MwtV= vapor molecular weight.• Calculate the net area required.

• Calculate the diameter.

V

VMwtV

max

Vnet U

VA max

5.04

netAD

• Calculate the maximum volumetric flow rate.

• Calculate the column area.

• Calculate the net area.

• Calculate the active area.

• Calculate weir length.

L

LxMwtrateliquidvolumetric

max

2

4DAC

dCn AAA

dca AAA 2

Dlengthweir 75.0

• Calculate the actual minimum vapor velocity.

• Calculate the thickness.

Where:t= thickness.P= pressure.r= radius.S= working stress.Ej= efficiency of joints.CC= allowance for corrosion.

• Calculate the cost.

hA

ratevaporvelocityvaporactual

.min.min

Ci CxPSxEj

Pxrt

6.0

ResultsEquipment Stripper T-102

Type Continuous distillation column

Material of construction Carbon steel

Insulation Mineral wool

Operating temperature, °C 110

Operating pressure, atm 3

Height of beds 0.75

Diameter, m 3.17

Thickness, m 0.0127

Number of beds 10

Height, m 13.2

Cost, $ 353,933