Chapter 4
The irreversible gas phase reaction A+B2C is carried out in a PFR reactor. The reaction is non-elementary in that it is first order in A and zero order in B. The feed is equal molar in A and B, and the pressure at the entrance is 10atm and the pressure at the exit is 2atm.
Additional information:
FA0=100 mol/s
K=1dm3/kg.s
CA0=1mol/ dm3
1)What is the conversion exiting the reactor?
2)If the flow were turbulent, what would be pressure drop if the cross sectional area is increased by a factor 2 and the particle size decreased by a factor of 10? All other conditions
remain the same. (Hint: in the turbulent flow, the Ergun equation neglects the part of 150(1-) /Dp. Reference: R.B.Bird, transport phenomena (New York, Wiley, 1960), p. 200.)
Answer: 
1)X=0.5
2)Pressure drops too great, no flow under these conditions.
This problem is to study the pressure drop in PBR.
Mole balance, rate law, stoichiometry and Ergun equation are used to solve the problem.
The main point:
1.Calculate  using the pressure drop
2.The relation between 0 and cross sectional area and particle diameter.
Solution:
1)                  
         
2)
                  (For turbulent flow)             
So
             
Calculate the new pressure drop
Before the exit of PFR, p=0
Chapter 8
The elementary reversible gas phase reaction A 2B is to be carried out adiabatically. Pure A is fed at a rate of 2 mol/min, at temperature of 373 K, and at concentration of 0.01 mol/dm3.
Additional information:
HR= -3500 cal/mol at 373 K
Ke=0.05 at 373 K
What is the adiabatic equilibrium temperature and conversion?
Answer:             
This problem is to study the steady-state nonisothermal reactor.
reaction order
Stoichiometry, the relation between equilibrium constant and conversion, Van’t Hoff’s equation and energy balance are used to solve problem
The main point: mole balance and energy balance.
Solution:
Mole balance:
=1
             
         
Energy balance:
CP=0
Combining the last two equations:
           
Chapter 12
Consider a gas-solid (catalyst) reaction in which the reaction is zero-order, and the solid particles have “slab” or “flat-plat” geometry with two faces permeable to A. The thickness is 2L.
1)Derive the diffusion equation in nondimensional form for A together with the expression for the Thiele Modulus.
2)Solve the equation in 1) to give the nondimensional concentration

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