Study On The Extreme Optimization Control Of Two-phase Anaerobic Digestion Process Of Lignocellulosic With Hydrogen And Methane Productio

In recent years,with the rapid development of the international economy,the development model of traditional petrochemical energy has become unsustainable,and my country has paid more and more attention to renewable green energy.At present,coal,petroleum,and other fossil energy still occupy a large proportion of my country’s energy consumption.Among them,the utilization rate of abundant biomass energy in my country is low,and more and more organic wastes(such as lignocellulose)are not used reasonably.It is not conducive to the sustainable development of our country.As a green and efficient organic waste treatment technology,anaerobic digestion technology uses anaerobic microorganisms to degrade our intractable organic wastes and generate green energy-hydrogen and methane,which is conducive to improving the current environmental sanitation problems.In this thesis,aiming at the coproduction process of hydrogen and methane in the lignocellulose two-phase anaerobic digestion system,based on the extremum search control algorithm,the maximum gas production in the anaerobic digestion process is taken as the optimization objective,and the optimal control research is carried out.The specific work is introduced as follows:(1)Establish a co-production process model of Lignocellulose cascade two-phase anaerobic digestion system(LCTADS): According to the existing biology and the latest research results of the Institute of Microbiology of the Bulgarian Academy of Sciences,the LCTADS model is established based on the reaction mechanism of lignocellulosic two-phase anaerobic digestion and the law of conservation of material quality.Based on the Matlab/Simulink simulation software,the numerical research and analysis of the open-loop model is carried out,and it’s verified that the system has a maximum point of gas production.(2)Verify the applicability of the extremum search control algorithm in LCTADS:In order to reduce the accuracy requirements of the model,for the co-production process of hydrogen and methane in LCTADS,perturbation extremum search control and sliding mode extremum search control are respectively applied to the model.In terms of numerical analysis,considering LCTADS material input changes,based on Matlab/Simulink simulation software,according to the output research under LCTADS extremum search control,the relatively fast convergence of the dynamic output under the perturbation extremum search control and the relative stationarity of the dynamic output under the sliding mode extremum search control are obtained,which verify the applicability and optimization of extreme value search control.(3)Propose LCTADS extremum search control based on unscented Kalman filter:Aiming at the problem of slow convergence in the extremum search control of LCTADS,an extremum search control based on unscented Kalman filtering is designed,which uses the gradient estimator of unscented Kalman filtering to obtain more accurate gradients.Based on Matlab/Simulink simulation software,comparative simulation experiments of LCTADS process control under stable and changing input materials were carried out respectively,and it’s verified that the proposed algorithm has a faster convergence speed and improves the gas production of the system.(4)Propose sliding mode extremum search control of LCTADS with no steady-state oscillation based on Kalman filter gradient regulation: Aiming at the steady-state oscillation problem in the extremum search control of LCTADS,to further eliminate the steady-state oscillation in the sliding mode extremum search control,a Kalman filter gradient estimator with a smooth gradient estimation process is used,and a sliding mode extremum search control algorithm with no steady-state oscillation based on Kalman filter gradient regulation is proposed.Based on Matlab/Simulink simulation software,comparative simulation experiments of LCTADS process control under stable and changing input materials were carried out,and the no steady-state oscillation characteristic of the proposed control algorithm was verified.