Plate Heat Exchanger design in excel

PLATE HEAT EXCHAN SIDE-I FLUID:

Water

Flow Rate in kg/s Properties @ 43.5 C Specific Heat Thermal Conductivity Viscocity Density

m3/hr

J/Kg-K Watt/mK Ns/m2*(10^-3) Kg/m3

Dirt Coefficient from Coulson and Richardson table 12.9

139.32 38.68 4190 0.586 0.0013 999.564 30000

Thermal Conductivity of Alloy 316 @ 23 C

W/m-K

Temperature In Temperature Out Average Temp for calculating Properties TD1=TI1-TO2 TD2=TO1-TI2

C C

Logarithmic Mean Temp Diff

16.3 49 38 43.5 12.879 8 10.247

No of Transfer Units=(TI1-TO1)/LMTD

1.074

Ft found from fig:12.62 of Ch Engg Design by Coulson and Richardson is 2:2 pass arrangement assumed U(Overall Heat Transfer Coeficient) assumed is from fig 12.2 Mass Flow Rate Heat Duty is HT Area required Plate Length Plate Width Plate thickness Plate Spacing No of Plates per pass Plate (Length * width)

passes

2

W/m2-K Kg/s W m2 m m m m

3088 38.683 1782887 60.92 0.8 0.7 0.0005 0.003 54.5 0.56

m2

Number of Channels/pass

54

No of Plates Required Number of Plates rounded up Channel Cross section area is (width * spacing)

Plates Plates

De or hydraulic mean radius is

m

108.78 109 0.0021 0.006

Calculation for Channel Velocity SIDE-1 Water Channel Velocity (MFR/(D*Channel CS* no of channels/pass) m/s Reynolds Number (Nre)

0.34 1637.36

Prandtl Number Npr

8.94

Heat Transfer Coefficient is

W/m2-K

7488.67

Overall Heat Transfer Coefficient calculated

W/m2-K

3088.3

Pressure Drop Calculation The Plate Pressure drop can be estimated using a form of the equation for flow in the ΔPp= conduit Lp The path Length Gp/ρ

up

Friction Factor

jf=

For this PHE jf= Path Length =

8jf(Lp/de)(ρup2/2)

0.6x Re^(-0.3)

0.065 Plate length x Number of Passes 1.600 m

ΔPp= The Port Pressure drop due to contraction and expansion losses through the ports in the plates must be added to the friction ΔPpt= loss

8089.7 N/m2

1.3Np(ρupt2/2)

The velocity through the ports=w/ρAp, m/s

upt

mass flow through the ports, kg/s

w

Area of the ports, m2

(Πdpt2)/4

Port diameter,m

dpt

Number of Passes

Np

Take Port Diameter as Port Area is Velocity through Port ΔPpt= Total Pressure drop=

125 mm 0.012 m2 3.152 m/s 12912.1 N/m2 21001.8 N/m2 0.2 bar

PLATE HEAT EXCHANGERS SIDE-II FLUID

Water

Flow Rate in kg/s Properties @ 33.8 C Specific Heat Thermal Conductivity Viscocity Density

m3/hr

250.00 69.43

J/Kg-K Watt/mK Ns/m2*(10^-3) Kg/m3

4196 0.583 0.0013 999.75

Dirt Coefficient from Coulson and Richardson table 12.9

Temperature In Temperature Out

30000

C C

Avg Temp for calculating Properties

30 36.1

33.1

0.925

Mass Flow Rate

Kg/s

69.43

SIDE-2 Water Channel Velocity (MFR/(D*Channel CS* no of channels/pass) Reynolds Number (Nre)

m/s

0.61 2766.11

Prandtl Number Npr

9.56

Heat Transfer Coefficient is

W/m2-K

10760.98

Overall Heat Transfer Coefficient Asumed

W/m2-K

3088

sure Drop Calculation The Plate Pressure drop can be estimated using a form of the equation for flow in the conduit

ΔPp=

The path Length Gp/ρ

Lp

Friction Factor

jf=

up

For this PHE jf= Path Length =

0.6x Re^(-0.3)

0.056 Plate length x Number of Passes 1.600 m

ΔPp=

The Port Pressure drop due to contraction and expansion losses through the ports in the plates must be added to the friction loss

8jf(Lp/de)(ρup2/2)

6913.5 N/m2

ΔPpt=

1.3Np(ρupt2/2)

The velocity through the ports=w/ρAp, m/s

upt

mass flow through the ports, kg/s

w

Area of the ports, m2

(Πdpt2)/4

Port diameter,m

dpt

Number of Passes

Np

Take Port Diameter as Port Area is Velocity through Port ΔPpt= Total Pressure drop=

125 mm 0.012 m2 5.657 m/s 41585.4 N/m2 48498.9 N/m2 0.5 bar