System Design And Experimental Study Of Rice Straw By Microwave Pyrolysis

Bioenergy is an important renewable energy.China is a large agricultural country,has rich bioenergy resource reserves,especially the crops straw biomass,but the bioenergy utilization level is not high.Biomass pyrolysis is a kind of biomass thermochemical conversion mode,can obtain the product of gas,liquid and solid three forms,to achieve efficient utilization of biomass,but conventional pyrolysis technology of straw biomass needs pretreatment requirements,which increased the complexity of the straw utilization and energy consumption.However the microwave heating is quick and even,with penetrating and holistic benefits,it will be introduced into the straw pyrolysis.Not only could it greatly reduce the requirements of straw pretreatment,but also improve the composition and content of pyrolysis products.Thus explore the characteristics of the straw microwave pyrolysis,is a new kind of bioenergy conversion method.In this paper,the microwave pyrolysis system was designed firstly,the most common crops straw-rice straw was used as raw material secondly,and carried out on the pyrolysis experiment.By using gas chromatography,the gas product components was analyzed.The influence of test mainly studies are the pyrolysis temperature,microwave power,water and catalyst four factors on the rice straw microwave pyrolysis,gas products,liquid products,solid products and main gas CH4,CO2,H2 and CO volume percentage change.Finally,in order to reveal the pyrolysis temperature,microwave power,water and catalysts four factors on the combine influence of rice straw microwave pyrolysis,to obtain factor sequence and optimum pyrolysis reaction conditions of the gas product,the liquid product,the solid product and the main CH4,CO2,H2 and CO gas products,this article also has carried on the four factors and four levels orthogonal experiment and the best combination of pyrolysis experiment is carried out.Main conclusions are as follows:(1)Through the analysis of technical indicators and the use of the environment,according to the demand of the system,the main components are selected,and the PLC was taken as the controller,the configuration of touch screen as human-computer interaction interface of the microwave pyrolysis control system,and the WinCC flexible 2008 configuration software was used to develop the system of microwave pyrolysis the human-computer interface,and the ladder diagram programming language was used in Step7 Microwin software,the control program design of PLC machine.The results show that,the microwave pyrolysis system design is reasonable,the selection of proper,stable function,can satisfy the test requirements of microwave pyrolysis.(2)When rice straw microwave pyrolysis temperature pyrolysis is 600?,the reaction is more fully,the liquid yield,solid yield and gas yield remained basically unchanged,while the microwave power is 1.5kW,the reaction is not entirely,and in microwave power 1.8 kW,more liquid product is converted to gas product.(3)The moisture content have a significant impact on the rice straw microwave pyrolysis solid yield,the microwave power have a significant impact on the rice straw microwave pyrolysis gas products CO yield,and the moisture and catalyst are important influence factors on the rice straw microwave pyrolysis gas products H2 yield,among them,the selection of ZnCl2 catalyst have the best effect.(4)The degree of influence factors of moisture and catalyst on the rice straw microwave pyrolysis gas liquid solid three phase yield,the gas product of CH4 and H2 yield is much greater than the pyrolysis temperature factor and microwave power factor,and for rice straw microwave pyrolysis gas product of CO2 and CO yield,the degree of influence of microwave power factor and catalyst factor is far greater than the pyrolysis temperature factor and moisture factor.(5)When the pyrolysis was taken place at temperature 400?,microwave power 1.5kW,moisture content 61.84%,without catalyst,can obtain the smallest solid production rate of 12.29%and up to 67.39%of the gas production rate.When the pyrolysis was taken place at temperature 700?,microwave power 2.5kW,moisture content 61.84%,the catalyst selection ZnCl2,can obtain the biggest H2 yield was 44.94%,the smallest CO2 production rate of 20.98%,4.8%of the minimum production rate of CH4 and CO production rate of 29.27%.