The Study On Sulfur-containing Gases Release During Different Co-pyrolysis Of Coaland Biomass

In this study,the effects of different co-pyrolysis ways(directly mixed and indirectly layer-separated)on sulfur transformation behavior of Yangquan(YQR),Ordos(EDR)raw coals and their deashed and depyrite coals were investigated during their co-pyrolysis with biomass(corn-cob)in Ar and CO₂atmospheres.Pyrolysis-chromatography(Py-GC)was used to discover the effects of different biomass ratios(25%,50%,75%,100%)on sulfur transformation during these two co-pyrolysis of these coals and biomass in CO₂atmosphere.The effect of low content oxygen atmospheres(1%O₂-Ar,3%O₂-Ar)on sulfur transformation was also investigated during YQ raw coal,its deashed and depyrite coals during different co-pyrolysis.The main conclusions are drawn as following:(1)During same co-pyrolysis,the desulfurization ratios of these coals under CO₂atmosphere are all higher than those under Ar atmosphere,while char yields lower than that under Ar atmosphere.Under CO₂atmosphere,the main sulfur-containing gases are composed by H₂S and COS,while only H₂S in Ar atmosphere.The trend of total release amount of sulfur-containing gases is:indirectly layer-separated co-pyrolysis>directly mixed co-pyrolysis>single-pyrolysis.(2)Under CO₂atmosphere,the desulfurization ratios of these coals with same proportion of biomass(25%,50%,75%or 100%)during indirectly layer-separated co-pyrolysis is higher than that during directly mixed co-pyrolysis.Except from depyrited coal with 100%biomass during directly mixed co-pyrolysis,the desulfurization ratios of other coals are all positively related to the proportions of biomass during these two different co-pyrolysis ways.(3)During same co-pyrolysis,the order of desulfurization ratios of YQ raw coal,its deashed and depyrite coals is:3%O₂-Ar>1%O₂-Ar>Ar,while the order of char yields is just opposite.Under low content oxygen atmospheres,sulfur-containg gases are mainly composed by SO₂during coal single-pyrolysis,while mainly H₂S during co-pyrolysis.The total release amount of sulfur-containing gases under 3%O₂-Ar atmosphere is greater than that in 1%O₂-Ar atmosphere during same pyrolysis.