The Research Of Process Control Methods On The Production Of Ammonia Synthesis

As the main raw materials of chemical products, ammonia with the highest demand and production in all kinds of inorganic chemical products and occupies an important position in national economy. The synthetic ammonia plants in our country usually adopt the conventional PID control method to control ammonia synthesis process. There are two control difficulties. Firstly, the link of hydrogen nitrogen ratio is a complicated large delay link which is difficult to control, but the requirement of hydrogen nitrogen ratio control is so strict, and the control ability of conventional PID for large time-delay strong interference link is extremely poor. Secondly, the results prove that within synthetic tower there are strong coupling among each catalyst bed on the temperature control.In the light of the high temperature control precision demand for ammonia synthesis reaction in the tower, this would greatly affect the efficiency of ammonia synthesis.At first this paper analyses the reasons of difficult control above, after simply introducing the ammonia synthesis process and difficult control sections then in view of the two major problems put forward reasonable solution. For many disruptive big lag link,put forward the hybrid control method based on weighted fuzzy rules. It not only brings the characteristics of fuzzy control, such as the good dynamic response, the fast rise time and the small overshoot; but also has the characteristics of PID controller, such as the better dynamic tracking quality and steady precision. In addition, weighted fuzzy rules can realize the undisturbed switching. Its control effect is satisfactory and easy to implement.Given the advanced nature of control technical requirements and the strict requirement of hydrogen nitrogen ratio, put forward yet PSO(particle swarm optimization algorithm)control method to optimize the RBF neural network. This method makes up for the disadvantage that RBF can only local optimization, it has very high superiority for complex control. For the temperature control coupling of each beds in ammonia synthesis tower, designing a multivariable decoupling control method based on QDRNN network. It solved the problem of the coupling between the double variables of control system, at the same time it ensured good steady performance of the system.Then, this article details the process of algorithm, and in view of the controlled object models of two systems in the MATLAB environment using various methods to realize.The control effect is verified by comparison.Finally, the control algorithm could be implemented with the help of DCS andconfiguration monitoring interface is produced through choosing Siemens WINCC software.