Microwave Steam Co-gasification Characteristics And Comparative Study Of Bacteria And Lignite

China has abundant coal reserves,but low-rank coal occupies a large proportion and is difficult to utilize.As the fourth largest energy source,biomass plays an increasingly important role in the sustainable use of energy because of its special advantages.Gasification is an efficient and clean method to use energy,and microwave technology as a new heating method,because of its special heating characteristics,have been widely used in chemical or agricultural fields.Studies have shown that the co-gasification of biomass and coal can effectively overcome the difficulties encountered in their respective gasification and increase the efficiency of gasification.Therefore,this paper mainly focuses on the mixed raw materials of biomass and coal and the mixed semi-coke.The new microwave heating method and the traditional heating method were combined to study the characteristics of their respective steam co-gasification,and the effects of microwave and conventional heating methods on co-gasification were compared.This article first performed thermogravimetric tests in terms of Bacterial and lignite and their mixtures.It was found that biomass plays a catalytic role in the pyrolysis process of coal.The best quality blending ratio is 1:1.The addition of biomass can reduce the activation energy of pyrolysis,and the highest weight loss peak move to low temperature zone,but when the biomass blend ratio exceeds 50%,the synergy gradually becomes inhibitory.Through thermogravimetry after pickling,it was found that the Na and K elements in the biomass were the decisive factors.In addition,it is found that both pyrolysis and co-pyrolysis of biomass and coal are first-order reactions by solving the kinetic parameters and the linear fitting.In this paper,the microwave steam co-gasification and furnace steam co-gasification test bench were set up respectively.The raw materials of the Flammulina velutipes and Baoli lignite and their corresponding microwave pyrolysis semi-coke were used as test samples on two test benches.Co-gasification tests under different conditions were carried out.The comparison of semi-coke and raw materials and the comparison of different heating methods were carried out respectively.In addition,pyrolysis experiments and co-pyrolysis experiments of lignite and biomass were conducted separately.The kinetic parameters were also calculated.For the microwave steam co-gasification test bench,the gasification performance of different pyrolytic semi-coke samples was studied.It was found that the activity of semi-coke obtained by the low microwave power with a mass ratio of 1:1 was better,and BET and SEM were performed.According to the analysis,it was found that high temperature easily lead to the deactivation of active sites and ordering of carbon structures.And for the special semi-coke(pyrolytic power:500W;mass ratio:1:1),steam flow,solid phase residence time and other parameters were investigated during the co-gasification process.The research found that increase microwave power,appropriately increase steam flow and solid phase residence time can improve the gasification effect.In addition,the synergistic effect of the co-gasification process was explored by pickling.It was found that the gasification effect of the semi-coke after the pickling was relatively low.It is the pickling that results in a decrease in the K and Na content.In addition,on the basis of this test bench,the co-gasification of raw materials was also carried out in terms of microwave power,steam flow rate and catalysts.Finally,a comparative analysis was performed on the co-gasification of semi-coke and raw materials under microwaves.The semi-coke was found showed better results in the microwave co-gasification.For the electric steam co-gasification,the semi-coke and raw materials were also conducted respectively.The specific variables were also studied from temperature,steam flow,and mass blending ratio.The conclusion is similar to the microwave steam co-gasification.Finally,by measuring the temperature of the gas produced at the outlet of the reactor,the microwave and electric heating conditions are determined to compare the effects of different heating methods on the semi-coke and the raw materials.The study found that for the semi-coke,because of its hotspot effect,makes microwaves more advantageous than electric heating.For raw materials,electric heating shows relatively better gasification effects.In addition,through the step-by-step comparison of the raw material in gasification process,it was found that the pyrolytic gas plays an impediment role in the steam co-gasification of materials.The reason is that the pyrolysis of volatile substances will cause the deposition to affect the reaction of carbon and steam.