Chapter 28: Open-Ended Problems

ILLUSTRATIVE EXAMPLE 28.11, Page number: 600

In [11]:
hm1 = 50000                      #Mass flowrate (lb/h)
hcP1 = 0.65                      #Heat capacity (Btu/lb.°F)
hTi1 = 70                        #Inlet temperature (°F)
hTo1 = 300                       #Outlet temperature (°F)
#For stream 2 to be heated:
hm2 = 60000                      #Mass flowrate (lb/h)
hcP2 = 0.58                      #Heat capacity (Btu/lb.°F)
hTi2 = 120                       #Inlet temperature (°F)
hTo2 = 310                       #Outlet temperature (°F)
#For stream 3 to be heated:
hm3 = 80000                      #Mass flowrate (lb/h)
hcP3 = 0.78                      #Heat capacity (Btu/lb.°F)
hTi3 = 90                        #Inlet temperature (°F)
hTo3 = 250                       #Outlet temperature (°F)
#From table 28.4:
#For stream 1 to be cooled:
cm1 = 60000                      #Mass flowrate (lb/h)
ccP1 = 0.70                      #Heat capacity (Btu/lb.°F)
cTi1 = 420                       #Inlet temperature (°F)
cTo1 = 120                       #Outlet temperature (°F)
#For stream 2 to be cooled:
cm2 = 40000                      #Mass flowrate (lb/h)
ccP2 = 0.52                      #Heat capacity (Btu/lb.°F)
cTi2 = 300                       #Inlet temperature (°F)
cTo2 = 100                       #Outlet temperature (°F)
#For stream 3 to be cooled:
cm3 = 35000                      #Mass flowrate (lb/h)
ccP3 = 0.60                      #Heat capacity (Btu/lb.°F)
cTi3 = 240                       #Inlet temperature (°F)
cTo3 = 90                        #Outlet temperature (°F)

#Calculation:
H1 = hm1*hcP1*(hTo1-hTi1)        #Heating duty for stream 1 (Btu/h)
H2 = hm2*hcP2*(hTo2-hTi2)        #Heating duty for stream 2 (Btu/h)
H3 = hm3*hcP3*(hTo3-hTi3)        #Heating duty for stream 1 (Btu/h)
H = H1+H2+H3                     #Total heating duty (Btu/h)
C1 = cm1*ccP1*(cTi1-cTo1)        #Cooling duty for stream 1 (Btu/h)
C2 = cm2*ccP2*(cTi2-cTo2)        #Cooling duty for stream 2 (Btu/h)
C3 = cm3*ccP3*(cTi3-cTo3)        #Cooling duty for stream 1 (Btu/h)
C = C1+C2+C3                     #Total Cooling duty (Btu/h)

#Result:
print "Table: Duty Requirements."
print "Stream                   Duty, Btu/h"
print "1                       ",round(H1)
print "2                       ",round(H2)
print "3                       ",round(H3)
print "4                       ",round(C1)
print "5                       ",round(C2)
print "6                       ",round(C3)
Table: Duty Requirements.
Stream                   Duty, Btu/h
1                        7475000.0
2                        6612000.0
3                        9984000.0
4                        12600000.0
5                        4160000.0
6                        3150000.0