Influence Of Biomass Ash On The Gasification Reactivity And Ash Fusion Characteristics Of Coal

In this paper,the effects of biomass(corn stalk,wheat straw,poplar sawdust)ash as catalysts on the gasification reaction of coal(Jincheng anthracite,Shenmu bituminous coal,Dongming lignite)and the melting characteristics of coal ash were studied.The results show that the reaction temperature,biomass ash type,biomass ash mixing ratio and addition method all affect its catalytic effect,and lead to different coal gasification characteristics.The reaction rate of Jincheng anthracite char gasification with 20%corn stalk ash increased by 1.8 times,the reaction rate of Shenmu bituminous coal char with 20%poplar sawdust added was increased by 2.04 times,and the reaction rate of Dongming lignite char with 20%poplar sawdust ash increased by 2.92 times.With the increase of gasification reaction temperature,the gasification reaction rate of coal char with biomass ash also increases.The reaction rate of coal char was affected by the ashing temperature.The reaction rate of coal charslow down with the increase of ashing temperature.The gasification reaction rate of coal char with ash filtration was better than that of mechanical stirring and impregnation method.According to the analysis results,it can be concluded that the main factors affecting the catalytic activity of biomass ash are the content of alkali metals and alkaline earth metals(especially the content of water-soluble alkali metals and alkaline earth metals)in biomass ash.The gasification reaction characteristics of coal char was affected by the physical and chemical structure evolution of coal char during the gasification process,such as the specific surface area,carbon structure and changes of mineral composition.At the same time,the addition of biomass ash will also affect the ash melting characteristics of coal.Therefore,this paper alsofocused on the ash melting behaviors of biomass/coal mixture.This paper investigates the melting characteristics of the ash of three types of coal and three types of biomass mixed sample.The effects of biomass addition ratio on the melting characteristics of Jincheng anthracite,Shenmu bituminous coal and Dongming lignite ash were investigated.Combined with X-ray fluorescence spectroscopy(XRF)and X-ray diffraction analysis(XRD),the ash composition and crystal structure of mixed ash were analyzed,indicating that the addition of biomass can influence the melting temperature of coal ash by changing the mineral composition of mixed ash.The melting characteristics of 42 groups of coal ash,biomass ash and mixed ash were determined by characterization and experiment.The three-layer BP neural network model with 12 inputs and 4 inputs was used to predict the gray melting point,and the simulation results showed that the difference between the predicted value and the experimental value was small,and the R~2 was greater than 0.93,indicating that the BP neural network model can be used for the prediction of ash melting temperature.