Answer Happy

1. Alternatives for cooling a batch exothermic reaction a) The first-order, liquid-phase, exothermic reaction A → B takes place in a batch reactor. At t = 0 h, all the reactant A is present in the reactor (no B present) at the required reaction temperature and the reaction is initiated by adding a small amount of catalyst. At t=0 h, an inert coolant flow to the reactor is initiated to control the reaction temperature. The reaction temperature is kept constant at 400 K, by varying the flowrate of the coolant. The coolant C temperature is 390 K. i) Calculate the flowrate of the coolant (in kg sl) at the start of the reaction (t=0 h) [7] ii) Calculate the flowrate of the coolant (in kg sl) at t=2 h after the reaction started S [3] iii) When is the coolant flowrate higher (at t=0 h or t=2 h) and why? [3] iv) How would the results change if the reaction was not first order? [2] b) Another way to keep the reactor temperature constant (at 400 K) is by using a cooling jacket where a boiling fluid is flowing to keep the reaction temperature constant. i) Calculate the amount of heat that the boiling fluid is removing (in Js !) at the start of the reaction (t=0 h) [3] ii) Calculate the amount of heat that the boiling fluid is removing (in J s-1) at t= 2 h after the reaction started [3] iii) When is the heat removal higher (at t=0 hr or t= 2 hr) and why?
iv) Comment on the advantages and disadvantages of the above cooling methods (by coolant added to the reaction mixture as in a) and by a cooling jacket as in b)) [2] State any assumptions you are making clearly. S Additional Information for Question 1. Reaction rate constant at 400 K, Heat capacity of all components, Heat of reaction at 400 K, Initial concentration of A, Initial volume of reaction mixture, k= 1.2 x 10-4 5-1 Cp=4 J giá: AHRx = - 50,000 J mol-1 CA0 = 5 mol dm-3 V = 1.5 m3 =- =