Optimal operating strategies for semi-batch reactor used for chromium sludge regeneration process

This paper deals with controlling of a semi-batch nonlinear reactor used for chromium sludge regeneration process. The aim is to process the largest amount of chromium filter cake (chromium sludge) in the shortest possible time. The reactor has to be cooled because of strongly exothermic process. For safety reasons the temperature should not exceed 100 °C. In this study the reactor is controlled by two manipulating inputs: filter cake feeding flow rate and cooling water temperature. The speed of the whole process depends on the filter cake feeding flow rate – in case of a large amount filter cake addition a sharp temperature rise follows. The controller must be able to find optimal strategy between the filter cake dosing and the cooling temperature to reach the shortest possible process time. In order to deal with process nonlinearities here an online identification must be used. Results obtained using the proposed control method are then compared with our previous research, especially with control method using only one manipulating input filter cake feeding flow rate. Key-Words: temperature control; online identification; semi-batch reactor; PID; pole placement