The Research Of Temperature Control Technology Of Ammonia Evaporation Tank

The process of ammonia evaporation is one of the important taches in the process of the iron oxide red production and wastewater handle for Titanium yellow powder production. The temperature control of the ammonia evaporation system directly affects the quality of ammonia gas, and then affects the running of the entire production system. To keep the distilling stable, the temperature in the ammonia evaporation tank as the key of the technic must be controlled at about101℃. It is difficult to find the exact mathematical model of the ammonia evaporation system for its nonlinear, uncertainties and time delay. Therefore, conventional control methods which are based on deterministic models and without time delay compensation are unable to adapt to the variation characteristics of the distilling temperature, so that their control performance can not meet the requirements of the ammonia evaporation production. Adaptive ability and anti-disturbance performance of the temperature in the ammonia evaporation tank are the main engineering problems for the control system to solve.Considered the characteristics of the temperature control of the ammonia evaporation tank, the approximate linear model of the ammonia evaporation process is proposed by the hypothesis and simplification based on the mechanism. On the basis of it, adaptive smith control scheme with anti-disturbance controller is proposed on the temperature control. Smith predictor controller is an effective way to solve delay system, however the routine smith predictor controller is very sensitive to model. The control performance will be seriously affected once the model mismatch occurs. Adaptive smith temperature control system is proposed after combining adaptive control with smith predictor control against the mismatch. Considering the disturbance that may occur in the ammonia evaporation system, the anti-disturbance controller is designed. The simulation results fully show that the adaptive smith temperature controller with the anti-disturbance controller still has good control performance in the case of model mismatch and eliminates the influence of disturbance to the system effectively. The hardware and software of the ammonia evaporation temperature control system were designed based on the adaptive smith controller with anti-disturbance, and them are used for the real-time monitor and control on the temperature process in the ammonia evaporation tank.