Changes Of Sulfur Elements During Co-pyrolysis Of Coal And Corn Stover

The co-pyrolysis of coal and biomass mainly has the following factors:pyrolysis temperature,pyrolysis time,catalyst,mixing ratio of biomass and coal,alkali metal ions,pyrolysis atmosphere.This article focuses on the study of the effects of pyrolysis temperature,pyrolysis atmosphere,and staged co-pyrolysis on the changes of coal and biomass co-pyrolysis sulfur.This paper uses experiments to explore the process of sulfur transition in the co-pyrolysis process,uses a horizontal tube furnace to conduct experiments and uses FTIR(Fourier infrared flue gas analyzer)to determine the gas composition,and selects local corn stalks and sorghum stalks in Harbin.And coal as the experimental raw material.The pyrolysis temperature is set in the temperature range of 300-900?,and the mixing ratio of biomass and coal is 1:1.The reaction atmosphere is selected as a nitrogen atmosphere and a weak oxidizing atmosphere(3%,5%,7%concentration of oxygen,nitrogen and carbon dioxide mixed gas).Based on the mechanism of free radical pyrolysis,it is generally believed that the co-pyrolysis process of biomass and coal is mainly the interaction between small molecular free radicals produced by pyrolysis.In order to eliminate the influence of solid-phase substances such as minerals and alkali metals in biomass on co-pyrolysis,a pyrolysis gas co-pyrolysis experiment was designed to separate biomass from coal and use biomass pyrolysis gas to pyrolyze coal;The contrast of pyrolysis can clearly observe the influence of the alkali metal ions of the birth substance on the sulfur transition during the pyrolysis process.After the sample was pyrolyzed in a N2 atmosphere at 300? and 400? for a period of time by staged pyrolysis,the sample was pyrolyzed in a N2 atmosphere at 600? to explore the effect of staged pyrolysis on the sulfur content of coke.The amount of change.The experimental results show that the sulfur element is difficult to remove during the pyrolysis of coal under N2 atmosphere,even if the sulfur removal rate does not exceed 90%under 800?.The desulfurization rate of coal in a weakly oxidizing atmosphere alone can reach 95%at 500?,and the coke yields of the two do not differ by more than 5%at the same temperature.The synergy of coal and corn stalks under N2 atmosphere is significantly higher than that of weak oxidizing atmosphere(triple).Experimental results show that coal pyrolysis alone can be used to produce clean solid fuels in a weakly oxidizing atmosphere.The sulfur-containing gases COS,SO2,CH4S and CS2 released during the pyrolysis process all overflow in large amounts at 600?.This article also found that CH4S is the product of the secondary reaction through a staged pyrolysis experiment,and its output is mainly related to the output of methane and methanol;CS2 is mainly generated in the solid phase through direct reaction of free radical exchange,and is rarely generated by the secondary reaction.The staged co-pyrolysis in an inert atmosphere can reduce the sulfur content in the gas and solid phases of the product by reducing the occurrence of secondary reactions,and increase the sulfur content in the tar.