Experimental Study On Biomass Molding Fuel Pvrolvsis And Gasification In Fixed Beds

Biomass, with its advantages of large output, zero emission of CO2has become an important renewable energy to replace the fossil fuels. As an important thermochemical conversion technology, biomass pyro lysis gasification technology has been more and more concerned. The ordinary straws of agricultural crops and sawdust have the disadvantages of being loss, small density and low calorific value of unit volume and it is not convenient to use them as fuel, causing the numerous straws of agricultural crops abandoned. The biomass fuel modeling technology well solves this problem, and can change the burning characteristics of bio masses such as sawdust and straws, realizing rapid, clean and high-efficiency burning. The theoretical and technical research on the gasification of biomass molding fuel is an important factor to promote the promotion and application of biomass molding fuel.First, self-made large material (2g) thermogravimetry was adopted for isothermal pyrolysis research on the biomass components, chemical kinetic method is used to fit the one-equation velocity model of mass loss and time in the process of pyrolysis and the kinetic parameter of macro model was calculated. The result indicated that the isothermal pyrolysis characteristics were significantly different from those of the thermogravimetric analysis, the temperature gradient in the process of reaction was large, the internal materials need the external thermal transfer, so more peak values occur in the process of reaction due to mutual overlapping, and when the temperature rose, the time when peak value occurs was early and the peak value was large.Thermogravimetric analysis method emphasizes the determination of mass change of the reactant, so it is unable to involve in the reaction of gaseous product, the pyrolysis product is analyzed quantitatively with tube furnace. The characteristics of pyrolysis gas production of29material on the tube furnace were analyzed, the instantaneous gas production characteristics were analyzed, law of influence of different temperatures and N2flows on the calorific value of gas components was researched and the influence of CaO additive is researched. The raising of temperature can improve the calorific value of gas produced substantially, smaller N2flow shortens the gas retention time and gasification was fully reacted. The addition of CaO had an obvious catalytic action, which could increase the content of H2and reduce CO2substantially, promoting the splitting of tar and improving the quality of gas substantially.Then air gasification experiment of continuous feeding was conducted to the biomass briquette fuel on the stet-up static bed gasification experiment table. The influence of five factors (temperature, ER, humidity, steam added and CaO added)on such parameters as gas product composition, calorific value, gasification efficiency and gas production rate of biomass molding fuel was analyzed. The experimental analysis indicated that with the increasing of temperature, the reaction degree became more intense and gasification efficiency was improved from58%to about68%. With the increasing of ER, the content of combustible componentsH2, CH4and CO in the gasified gas reduced, reducing the calorific value of gasified gas. The gas calorific value and gasification efficiency presented a trend of first increasing and then reduction with the increasing of moisture of materials, the humidity of materials should be controlled within a certain range, which is beneficial for gasification. After CaO is added as the catalyst, the content of CO2in air gasification and the calorific value of gasified gas increased significantly. The addition of CaO significantly increased the content of H2and CO in the gasification product. By comparing the biomass raw material and the gasification effect of biomass molding fuel made, it was found that the biomass molding gasification had a better effect and the gasification process was more stable.From the aspect of promoting biomass gasification furnace, the greenhouse gas emission reduction capacity of a4t coal-burned boiler after being changed as biomass gasification direct burning furnace is calculated based on CDM application, it was found that the emission of5965.24tCO2could be reduced within one year with a very good social benefit and environmental benefit.