Design And Experimental Study Of Temperature Control Systerm For Biogas Dry Fermentation

Biogas dry fermentation,emerging as a prominent technique divergent from the wet fermentation,solidified its significance in biomass domain by its advantages such as low power and water consumption as well as simpler tailing treatment etc.Varied researches and results are implemented and obtained within the theme.As a key factor,the control of temperature still remains technical difficulties to be solved.Three aspects are mainly studied from the optimization of fermentation equipment,the control algorithm of fermentation temperature,and hardware and software designing for the temperature-control system for the biogas dry fermentation.The main research works and results of this thesis are as follows:(1)In order to mitigate the effect of mixing difficulty of solid fermentation,the spiral screw agitator was introduced and the mixing performance of the agitator in solid fermentation was simulated by the FLUENT software.The design of jacket heating system and heat preservation device for fermentation temperature control was put forward.A new multi-point temperature detection device was proposed to solve the problems of temperature detection.(2)According to the heat transfer equation of the fermentation heating system,the transfer function of the heating system was deducted and the parameters were identified by MATLAB software.A temperature compensation algorithm was proposed to solve the problem of large thermal inertia of jacket heating device,and temperature control was divided into two stages: temperature compensation algorithm control and intelligent algorithm control.A fuzzy algorithm and an RBF neural network algorithm are used to optimize the PID controller,and compares the two control effects through simulation.The RBF neural network PID algorithm is better,the maximum overshoot is 0.55 ° C,and the rise time and stabilization time are 548 seconds and 957 seconds,respectively.(3)The hardware and software of intelligent control system were designed,of which the lower computer was the control circuit with the STM32 microprocessor as the core,and the upper computer interface was built by Lab VIEW software.According to the requirements of temperature detection device,the multi-channel temperature detection module circuit with Zig Bee wireless transmission and battery power supply was designed.The validity of fermentation temperature control algorithm was proved by biogas dry fermentation experiments.