The elementary, irreversible, gas-phase reaction 

A→B→C is carried out adiabatically in a PFR packed with a catalyst. Pure A enters the reactor at a flowrate of 20dm3/s, at a pressure of10 atmand a temperature of450 K.

 

 Additional information:

HA∘=−70 kJ/mol, HB∘=−50 kJ/mol, HC∘=−40 kJ/mol(all heats of formation are referenced to273 K)

CP,A=40 J/mol−K, Cp,B=25 J/mol−K, CP,C=15 J/mol−K

 

For the reaction:k1(450 K)=0.133dm3/kg⋅cat-s,                                         

E=31.4 kJ/mol                                                                      

For the heat exchanger (where used):Ua/ρB=1.5 J/(s−kg⋅cat−K) whereUis the overall heat transfer coefficient,ais the heat exchange area per unit volume of the reactor, andρBis bulk density of the catalyst. 

 

a. Plot the conversion and temperature down the length of the plug-flow reactor for a catalyst weight of30 kg. Assume no pressure drop. What is the catalyst weight required for80%conversion? 

b. What catalyst weight is necessary to achieve80%conversion in a CSTR? 

c. Account for pressure drop in the reactor usingα=0.0075/kg-cat. Plot the temperature, conversion and pressure along the length of the reactor(W=30 kg). 

d. Plot the temperature and conversion profiles for the PBR(W=30 kg)with pressure drop where a heat exchanger has been added, and the flowrate of cooling fluid is high enough that its temperature is constant at50∘Ce. Repeat part e above with cocurrent and countercurrent heat exchangers where the mass flowrate of cooling fluid in the heat exchanger(m˙c)is0.2 kg/s, its heat capacity(Cp,c)is 5,000J/kg−Kand it enters the heat exchanger at a temperature of50∘C.

Answer rating: 100% (QA)

a To plot the conversion and temperature down the length of the plugflow reactor PFR for a catalyst weight of 30 kg we can use the mole balance and energy balance equations The mole balance equation f... View the full answer