Research And Optimization Design Of Biomass Pyrolysis System

Biomass energy is clean energy with high yield and low recovery.The biomass pyrolysis system has the function of recovering biomass energy.At present,the recovery components of pyrolysis products(different biomass oil production and carbon production at different temperatures)and pyrolysis conditions are still in the analysis stage.In this paper,based on the pyrolysis characteristics of pyrolysis device and process optimization,by adopting the combination of experiment and simulation method,by thermogravimetric experiment,data mining methods of prediction,the temperature control of the pyrolysis device complete biomass pyrolysis temperature response characteristics,relationship between pyrolysis conditions and product characteristics,pyrolysis process temperature control optimization problems such as systemic research.Finally,the whole pyrolysis system is simulated.In order to improve the recovery rate of biomass energy,combined with thermogravimetric experiments of different biomass pyrolysis characteristics and kinetics of pyrolysis was analyzed,and the selection of higher biomass pyrolysis products as raw materials for the pyrolysis,proved that the three kinds of material of coke yield for rice husk>straw>sawdust,determined the main factors that influence the temperature of pyrolysis,The mathematical model of temperature control is established according to the experimental data.According to the data mining method,the SVM support vector machine algorithm of machine learning algorithm was selected in this paper,and the database of pyrolysis conditions and pyrolysis products was established by referring to the experimental data of literatures,and the prediction model was established.To predict the relationship between pyrolysis products bio-oil,biochar,gas and pyrolysis conditions,the coefficient of determination of carbon yield prediction model(R~2)established by literature data reached 0.982,the coefficient of determination of oil yield prediction model(R~2)established 0.989,and the coefficient of determination of gas yield prediction model(R~2)established 0.962.The correlation matrix of the prediction model is established.The pyrolysis conditions were optimized for different kinds of biomass,and the change of carbon,oil and gas yields of rice husk at400℃～800℃was predicted.According to the predicted results,the optimal pyrolysis temperature for the maximum available products of rice husk was 550℃.The mathematical model of temperature control of pyrolysis system is established according to the experimental data of pyrolysis in Chapter 2.For the key factors affecting the pyrolysis process,the temperature of the pyrolysis system was stabilized at 550℃for optimization control.Because the system belongs to large inertia,large lag and nonlinear system,it is difficult to obtain better control effect by using traditional PID control.By comparing several control algorithms,GA-BP-PID algorithm has the best control effect and improves the robustness and accuracy of temperature control.According to the analysis of pyrolysis sample composition and optimal temperature mentioned above,the process process of the whole pyrolysis system was simulated.Aspen Plus software was used to establish system simulation,and conclusions were drawn as follows:The calculated yields of bio-oil,bio-char and NCGs are 16.5%,26.5%and 57%,and the simulated results are in good agreement with the experimental results.