Design And Research Of A Biogas Power Generation Control System

Qingtongxia City of Ningxia Province,has built a large-scale biogas power generation project,which produces 12 thousand cubic meters of methane per day.The project mainly uses cow dung sewage as raw materials for fermentation.After pretreatment,they are put into fermentors to generate biogas.The biogas is purified to support power generation and supply resources to surrounding farmers,which not only achieves efficient energy utilization,but also reduces greenhouse gas emission.In order to realize automatic control of process process,a set of automatic control system should be designed to help operators to manage producing procedures and improve work efficiency.The paper introduces the detailed technological process of biogas power generation system.Based on that,it designs a complete set of biogas power generation control system.Practice has proved that the system is running stable,which is capable to meet the needs of production management for an enterprise.The control system of biogas power generation takes SIEMENS S7-300PLC as the main station,and hangs two ET200M as slave stations.It uses PROFIBUS Fieldbus for communication between the main station and slave stations.The monitoring system of the upper computer is developed and completed by MCGS software.It is a real-time monitor for production procedures,and have the functions of data recording and alarming.Through statistics of the amount and type of devices executed in the process system,the I/O points needed for PLC(Programmable Logic Controller)are determined by the system.Based on that,the hardware design of the control system is also completed.And the PLC control program of each process is designed according to the technological process and the related operation.Considering the characteristic temperature control of biogas fermentation,a fuzzy PID controller is designed to solve the problems during the control procedure,including modeling difficulty,lagging and inertia and so on.Through the simulation analysis,the designed fuzzy PID controller has a fast response speed and no overshoot at the same time.It is very favorable for the temperature control of biogas fermentation,and the control quality is improved obviously.