APPENDIX
clear
clc
R=8.314;
T=270+273;
k=(0.991e-2)*exp(-18330/(R*T))
Vo=1.335e4;
Xa=0.95;
P=5000;
yco=0.1567;
yh2=0.6991;
ymeth=0;
Pco=yco*P
Ph2=yh2*P
Pmeth=ymeth*P
LogofK=(3921/T)-(7.971*log10(T))+(0.002499*T)-((2.953e-7)*T^2)+10.2
Keq=10^LogofK
n=1.5;
r_methanol=k*((Pco*Ph2)-((Pmeth/Keq)*(Pco*Ph2^0.5)^n))/3600
%V_reactor=(Vo/k)*(log(1/1-Xa));
FAO=14790.4247985271;
W=FAO/(r_methanol)*Xa %Weight of Catalyst
den_cat=1300;
Vcatalyst=W/den_cat
Vreactor=3*Vcatalyst
CAO=FAO/Vo
Scaled_volume=Vreactor*1
Scaled_CatVol=Scaled_volume/3
NewCatWeight=Scaled_CatVol*den_cat
Hr=-4.5e4
mass_flo=165336.578900071;
Cp=35.18;
Tad=T+[((-Hr)*(FAO))/(mass_flo*Cp)]*Xa
Vrpi=Scaled_volume/pi
Vc=Vrpi/3
Diameter=nthroot(Vrpi,3)
Lenght=4*Diameter
Space_vel=Vo/Vrpi
Space_time=1/Space_vel
Bed_Length=4*NewCatWeight/(den_cat*pi*Diameter^3)
radiusDome=Diameter/2
VolumeDome=0.667*pi*(radiusDome^3)
TotalVolDome=VolumeDome*2
TotalVolReact=Vrpi+TotalVolDome
clear; clc
Feed = 2161
Ff=0.5544
Dd=0.9903
Ww=0.0103
D=((Feed*Ff)-(Feed*Ww))/(Dd-Ww)
W=Feed-D
disp ('Calculation of Minimum Ratio')
disp ('Feed is at saturated liquid condition, therefore')
q=1
Y_xy=0.8;
X_int=0.55;
Y_int=0.54;
Rec_grad= (Dd-Y_xy)/(Dd-X_int)
Rmin=Rec_grad/(1-Rec_grad)
R=1.3*Rmin
disp ('Calculation of Actual number of stages')
Slope_Rec=R/(R+1)
Rec_OL=['yrec=',num2str(Slope_Rec),'*xrec+',num2str(Y_int)];
disp(Rec_OL)
Nstages_theo=8
Nstages_act=Nstages_theo-1
plate_eff=0.7;
Ass1=['Assuming plate efficiency of ',num2str(plate_eff)];
disp(Ass1)
Nstages=Nstages_act/plate_eff
disp('Calculation of liquid and vapuor amounts in both sections')
disp('Rectifying Section')
Lo=D*R
disp('Vn=Lo+D')
Vn=Lo+D
disp('Ln=Lo')
Ln=Lo;
Lm=Feed+Ln
disp('Vm=Vn')
Vm=Vn
%
disp ('Liquid density of rectifying section')
rho_L1=791.7
disp ('vapour density of rectifying section')
rho_V1=2.9
disp ('Liquid density of stripping section')
rho_L2=943.3
disp ('vapour derho_L1nsity of stripping section')
rho_V2=3.4
disp('CALCULATION OF COLUMN DIAMETER')
disp('diameter of rectifying section')
rho_rect=rho_V1/rho_L1;
FLV_rec= (Ln/Vn)*(sqrt(rho_rect))
tray_spac=0.6;
Ass2 =[' assuming tray spacing of ', num2str(tray_spac)];
disp (Ass2)
disp('from Flooding velocity, sieve plate chart')
K1_rec=9e-2
Floodvel_rec=K1_rec*sqrt((rho_L1-rho_V1)/rho_V1)
disp('Dc- Column diameter,Ac- Column cross sectional area,Ad-Down comer
area')
disp('Aa-Active area, Ah-Holes area, An- Net area,Ua-Actual vapour velocity
required through the column ')
Ass3 = ['Assumming Ad=12% of Ac'];
disp(Ass3)
Flooding_rec=40;
Ass4 = ['Assuming ', num2str(Flooding_rec),'% Flooding'];
disp(Ass4)
actFloodvel_rec=(Flooding_rec/100)*Floodvel_rec
AvrgMolWt_rec=32*0.5552+18*0.4448
VapVel_rec=Vn*AvrgMolWt_rec/3600
An_rect=VapVel_rec/actFloodvel_rec
disp('An=Ac-Ad')
disp('An=0.88Ac')
Ac_rect=An_rect/0.88
Dc=sqrt(4*Ac_rect/pi)
Diameter_rec=['Therefore, the column diamaeter of the rectifying section is
', num2str(Dc), 'm'];
disp(Diameter_rec)
disp('diameter of stripping section')
rho_strip=rho_V2/rho_L2;
FLV_strip= (Lm/Vn)*(sqrt(rho_strip))
tray_spac2=0.6;
Ass5 =[' assuming tray spacing of ', num2str(tray_spac2)];
disp (Ass5)
disp('from Flooding velocity, sieve plate chart')
K1_strip=1.1e-1
Floodvel_strip=K1_strip*sqrt((rho_L2-rho_V2)/rho_V2)
Ass6 = ['Assumming Ad=12% of Ac'];
disp(Ass6)
Flooding_strip=40;
Ass7 = ['Assuming ', num2str(Flooding_strip),'% Flooding'];
disp(Ass7)
actFloodvel_strip=(Flooding_strip/100)*Floodvel_strip
AvrgMolWt_rec=32*0.5552+18*0.4448
VapVel_strip=Vn*AvrgMolWt_rec/3600
An_strip=VapVel_strip/actFloodvel_strip
disp('An=Ac-Ad')
disp('An=0.88Ac')
Ac_strip=An_strip/0.88
Dc_strip=sqrt(4*Ac_strip/pi)
Diameter_strip=['Therefore, the column diamaeter of the rectifying section is
', num2str(Dc_strip), 'm'];
disp(Diameter_strip)
disp('Number of Holes in a tray at rectifying section')
disp('Hole diameter is assumed 12mm')
Aa_rect=Ac_rect-(0.12*2*Ac_rect)
disp('Assume holes area is 10% of active area')
disp('Total holes area in a tray')
TrayHoleArea_rect=0.1*Aa_rect
Ah_rect=pi*(0.012^2)/4
Nholes_rect=TrayHoleArea_rect/Ah_rect
disp('Number of Holes in a tray at stripping section')
disp('Hole diameter is assumed 12mm')
Aa_strip=Ac_strip-(0.12*2*Ac_rect)
disp('Assume holes area is 10% of active area')
disp('Total holes area in a tray')
TrayHoleArea_strip=0.1*Aa_strip
Ah_strip=pi*(0.012^2)/4
Nholes_strip=TrayHoleArea_strip/Ah_strip
disp('Flow pattern identification and down comer selection')
LiqFlow_rect=((Ln/3600)*AvrgMolWt_rec)/993.4
disp('The flow pattern is Cross flow(single pass)')
LiqFlow_strip=((Lm/3600)*AvrgMolWt_rec)/795.2
disp('The flow pattern is Cross flow(single pass)')
disp('Calculation of height of the column ')
plate_thickness=3;
Ass8=['Assume thickness of plate ',num2str(plate_thickness),'mm'];
disp(Ass8)
liq_holdup=0.5;
Ass9=['Assume ',num2str(liq_holdup),'m for liquid hold up and vapor
disengagement'];
disp(Ass9)
Column_height= (Nstages-1)*0.6+liq_holdup+(plate_thickness/1000)
disp('Feed Tray Location')
Feed_Location=round(4/plate_eff);
Ass10=['Feed tray location is the ', num2str(Feed_Location),'th tray'];
disp(Ass10)
%%Pressure drop
Top_operating_pressure =101.3
h=100;
Ass11=['let h=',num2str(h),'mm'];
disp(h)
delta_P=1000*9.81*100e-3
Total_delta_P = delta_P*Nstages
Bottom_pressure=Top_operating_pressure+(Total_delta_P/1000)
k=
1.7090e-04
Pco =
783.5000
Ph2 =
3.4955e+03
Pmeth =
0
LogofK =
-3.1082
Keq =
7.7946e-04
r_methanol =
0.1300
W=
1.0808e+05
Vcatalyst =
83.1352
Vreactor =
249.4056
CAO =
1.1079
Scaled_volume =
249.4056
Scaled_CatVol =
83.1352
NewCatWeight =
1.0808e+05
Hr =
-45000
Tad =
651.7056
Vrpi =
79.3883
Vc =
26.4628
Diameter =
4.2979
Lenght =
17.1914
Space_vel =
168.1609
Space_time =
0.0059
Bed_Length =
1.3333
radiusDome =
2.1489
VolumeDome =
20.7942
TotalVolDome =
41.5884
TotalVolReact =
120.9767
>> >>
Feed =
2161
Ff =
0.5544
Dd =
0.9903
Ww =
0.0103
D=
1.1998e+03
W=
961.2040
Calculation of Minimum Ratio
Feed is at saturated liquid condition, therefore
q=
1
Rec_grad =
0.4322
Rmin =
0.7612
R=
0.9896
Calculation of Actual number of stages
Slope_Rec =
0.4974
yrec=0.49738*xrec+0.54
Nstages_theo =
8
Nstages_act =
7
Assuming plate efficiency of 0.7
Nstages =
10
Calculation of liquid and vapuor amounts in both sections
Rectifying Section
Lo =
1.1873e+03
Vn=Lo+D
Vn =
2.3871e+03
Ln=Lo
Lm =
3.3483e+03
Vm=Vn
Vm =
2.3871e+03
Liquid density of rectifying section
rho_L1 =
791.7000
vapour density of rectifying section
rho_V1 =
2.9000
Liquid density of stripping section
rho_L2 =
943.3000
vapour derho_L1nsity of stripping section
rho_V2 =
3.4000
CALCULATION OF COLUMN DIAMETER
diameter of rectifying section
FLV_rec =
0.0301
assuming tray spacing of 0.6
from Flooding velocity, sieve plate chart
K1_rec =
0.0900
Floodvel_rec =
1.4843
Dc- Column diameter,Ac- Column cross sectional area,Ad-Down comer area
Aa-Active area, Ah-Holes area, An- Net area,Ua-Actual vapour velocity required through the column
Assumming Ad=12% of Ac
Assuming 40% Flooding
actFloodvel_rec =
0.5937
AvrgMolWt_rec =
25.7728
VapVel_rec =
17.0893
An_rect =
28.7830
An=Ac-Ad
An=0.88Ac
Ac_rect =
32.7080
Dc =
6.4533
Therefore, the column diamaeter of the rectifying section is 6.4533m
diameter of stripping section
FLV_strip =
0.0842
assuming tray spacing of 0.6
from Flooding velocity, sieve plate chart
K1_strip =
0.1100
Floodvel_strip =
1.8289
Assumming Ad=12% of Ac
Assuming 40% Flooding
actFloodvel_strip =
0.7316
AvrgMolWt_rec =
25.7728
VapVel_strip =
17.0893
An_strip =
23.3598
An=Ac-Ad
An=0.88Ac
Ac_strip =
26.5453
Dc_strip =
5.8136
Therefore, the column diameter of the rectifying section is 5.8136m
Number of Holes in a tray at rectifying section
Hole diameter is assumed 12mm
Aa_rect =
24.8581
Assume holes area is 10% of active area
Total holes area in a tray
TrayHoleArea_rect =
2.4858
Ah_rect =
1.1310e-04
Nholes_rect =
2.1979e+04
Number of Holes in a tray at stripping section
Hole diameter is assumed 12mm
Aa_strip =
18.6953
Assume holes area is 10% of active area
Total holes area in a tray
TrayHoleArea_strip =
1.8695
Ah_strip =
1.1310e-04
Nholes_strip =
1.6530e+04
Flow pattern identification and down comer selection
LiqFlow_rect =
0.0086
The flow pattern is Cross flow(single pass)
LiqFlow_strip =
0.0301
The flow pattern is Cross flow(single pass)
Calculation of height of the column
Assume thickness of plate 3mm
Assume 0.5m for liquid hold up and vapor disengagement
Column_height =
5.9030
Feed Tray Location
Feed tray location is the 6th tray
>> Top_operating_pressure =
101.3000
100
delta_P =
981
Total_delta_P =
9810
Bottom_pressure =
111.1100