This unit is a semi-batch stirred tank reactor where feed stocks (simply called A & B) are reacted to form desired product (C). The user can add A and B by opening the feed valves. If the reactor is over-filled, the game has to be re-started. The reaction is exothermic ie heat is given out. This heat can be removed by the cooling jacket; the user can adjust the cooling water flow to this jacket. The reaction only goes very slowly at low temperatures but the reaction rate increases with temperature. One can increase the reactor temperature and the reaction rate by using steam to heat feed A and by not using cooling. However if the temperature goes too high, the cooling cannot cope and the reactor ‘runs away’. The challenge is to maximise the yield of C without exceeding the maximum permissible temperature.
The reaction rate between A and B is given by the following expression:
reaction rate = (mass A/total mass) * (mass B/total mass) * k1 * exp(-k2/(temperature+273))
where the rate depends upon the concentration of A in the reactor [mass A/total mass in reactor], the concentration of B [mass B/total mass in reactor] and an exponential term which shows how the rate increases with absolute temperature (degree K or temperature in degree C plus 273); k1 and k2 are constants chosen to give a batch time of three minutes.
The model considers the process in short time steps and for each step it calculates the reaction rate and the new reactor composition, the amount of heat produced, the amount of heat removed by cooling and hence the new reactor temperature.
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