Research Of PH Value Control System Of Beer Dilution Water

Water has very important roles to play in the process of beer production. The percentage of water reaches the maximum value in beer. This is the reason why water is called the blood of beer. In addition, due to a rising consumption and increasing output of beer, technology of high concentration brewing is accepted by more and more beer manufacturers. The quality of dilution water largely determine the quality of the final products in process of beer post-dilution. Therefore, in the beer production, it is very important to make the pH value in a certain range, or else it may debase product quality, cause waste of material, block the production, even make the enterprise competitive falling.With the adding acid system of dilution water in a brewery in JinZhou as example, this article studys problem of pH value control. On the basis of theory analysis for pH value control process, this article builds the dilution water’s static model and dynamic model, obtains nonlinear characteristic curve of pH value process, and then analyzes the characteristics of pH value control of dilution water that pH value process is a serious nonlinear process and has large lag, different interferences. Then this article uses existing pH Hammerstein model and improves the model to make it become the empirical model that is appropriate for this object. After that, the transfer function of the control object is obtained by unit-step response.(1) This article uses segmented linear design thought to design control algorithm of variable gain PID to compensate nonlinearity of pH value process and modified Smith predictor to compensate large lag of pH value process, and then makes simulations and analysis.(2)In order to improve system’s dynamic performance and precision of the system, a new intellectual control algorithm which is called PID control algorithm based on BP neural network is proposed to design the controller of controlled object in this article. At last, with the help of Matlab, this article makes the simulation and analysis of controllers that are designed using two different kinds of methods.The simulations reveal that segmented variable gain PID controller based on Smith predictor has good stability, whose control precision is within two percent, PID control controller based on BPNN has good robustness and anti-interference, whose control precision is within ten thousandths. PID controller based on BPNN is more appropriate than PID controller based on Smith predictor at the segmented border point. When fraction is similar to controlled object, PID controller based on Smith predictor is better than PID controller based on BPNN. What’s more, when it comes to interferences, PID controller based on BPNN is better than PID controller based on Smith predictor. Simulation and analysis of the designed controllers demonstrates the designed algorithm is very feasible and available. It provides a good theoretical support and practical basis for the research of pH value control system in future.