Study On Co-Gasification Characteristics Of Inferior Bituminous Coal And Biomass

Currently, with the problems of energy crisis and environmental pollution, it is very important to study the utilization of coal with biomass. The co-gasification technology of coal and biomass can prolong the life of coal and decrease the emission of CO2, SOX and NOX, which is significant in protecting the environment and reducing the consumption of fossil energy.In this paper, the inferior bituminous coal and biomass were chosen as the research object. The non-isothermal thermogravimetry analysis was taken to research the pyrolysis characteristics and nonlinear fitting of pyrolysis kinetic parameters. The isothermal thermogravimetry analysis was taken to research the gasification characteristics of char. The co-gasification experiments of coal and pine were carried out to study the effect of different conditions on gas characteristics with the gasification agent of oxygen-enriched air and steam.The pyrolysis and gasification thermogravimetry results indicate that: The synergistic interaction was observed during the co-pyrolysis of coal and pine; The sequence of the promoting effect of three kinds of alkali metal on co-pyrolysis is: K2CO3> Ca O> Na2CO3, respectively. The addition of pine can improve the gasification reactivity and reaction rate of inferior. The addition of K2CO3 can apparently improve the reaction of mixed char. The K2CO3 amount of 16.67% is the optimum value, and the thermogravimetry, carbon conversion and reactivity index reached the maximum, respectively. With the increasing of flow of CO2, the maximum mass loss rate, carbon conversion and the mean specific gasification rates increase. With the increasing of temperature, the weight loss rates increased. However, the void was collapsed at higher temperature and the further gasification reaction was decelerated. The gasification results in the fixed bed showed that: with the increasing, the reaction reactivity of inferior coal increased and the hydrogen content and gas yield increased significantly. The addition of pine changed the gas characteristics, which lead to the increase of specific surface area of mixed char. The addition of five kinds of metal compounds promoted the gasification of mixed char and the CO content changed significantly. The sequence of catalytic effect according to the combustible gas content, LHV, gas yield and carbon conversion is: K2CO3> Na2CO3> Fe2O3>Ca O>Ni O。The addition of steam in the oxygen-enriched air promoted steam gasification and water-gas shift reaction, which can optimized the gas distribution, especially for the increasing of hydrogen content and LHV and improved the gas yield and carbon conversion. The addition of K2CO3 enhanced reactivity of mixture. The gasification with K2CO3 under different ratios of pine significantly increased the hydrogen content, combustion gas yield and decreased the content of carbon in the mixture residue. With the increasing of temperature, the carbon conversion, hydrogen yield and combustion yield remarkably increased. As the addition of K2CO3 was 16.67 wt.%, the reactivity achieved the optimal effect, the hydrogen yield and combustion yield achieved the maximum value 2.45811m3.kg-1 and 3.12666 m3.kg-1, respectively.