Directional Regulation Of Sulfur During Blending Coal Pyrolysis Of High Sulfur Fat Coal And Prediction Of Sulfur Content In Coke

Because of the massive exploitation and utilization,high quality coking coal resources have been increasingly scarce.Meanwhile,with the rapid development and application of large-scale blast furnace and coal injection technology,the role of coke in blast furnace has been changed deeply and the requirement for coke quality has elevated.For the purpose of relieving demand-supply pressure of high quality coking coal resources and guarantee the coke quality,it is urgent and necessary to reasonably utilize the low grade high-sulfur coking coal,expand the coking coal species,reduce enterprise cost and promote the sustainable development of coking industry.Based on this,the correlation between the transformation and change of sulfur species and the volatile content,CaO and Fe2O3 content,sulfur content and forms in single and blending coal during pyrolysis were researched in the paper.The main research results are as following:(1)26 coals for blending coking with different properties were selected as experimental samples and their single pyrolysis experiment were carried out to correlate the interaction between sulfur content in coke and coal properties,such as sulfur content,volatile content and CaO and Fe2O3 content.A good fitting prediction model was established and can be used to provide some guides towards the prediction of sulfur content in coke within a certain application scope.(2)11 coals for blending coking which were used as raw materials in practical coking industry were optimized and selected from the 26 kinds of coking coals.The sulfur transformation behavior during single coal pyrolysis was investigated and the results showed that the differences of sulfur content and distribution in different coal lead to the variance of release behavior of sulfur-containing gases.The decomposition of some unstable organic sulfur in coal was the main source of sulfur-containing gases.(3)The 11 coals for coking were blended as PHM1 according to the blending ratio in practical coking industry,and two kinds of high-sulfur fat coal(FM3 and FM4)were selected to study the sulfur transformation behavior and interaction mechanism during the pyrolysis of PHM1 added with FM3 or FM4.The results showed that the accumulated amount of sulfur-containing gases increased with increasing ratio of FM3 and the decomposition of pyrite in FM4 under 600?lead to the increase of accumulated amount of H2S.Meanwhile,the much more alkaline matters contained in FM4 promoted the sulfur retained in the coke.After removing different single coal from blending coals,the release behavior of SO2 and H2S both changed little and the experimental values of sulfur content in coke were higher than the calculated ones.Besides,the proportion of sulfur in the solid phase increased with the increasing volatile content in the removing single coals.(4)The co-pyrolysis and resolving experiments of a high-volatile non-coking coal(Coal A)and PHM2,which stands for the blending coal that added 10%FM3 replace for FM1,were carried out.During the co-pyrolysis process,the decomposition of aliphatic branched chain structures in Coal A released large amount of active hydrogen radicals which either reacted with the sulfur radicals from blending coal or catalyzed the decomposition of some stable sulfur matters in coal,eventually lead to the increase of accumulated amount of sulfur-containing gases.The different amount of active hydrogen radicals in volatile resulted in the difference between experimental value and calculated value of sulfur content in coke.During the resolving pyrolysis process,for the interactions between Coal A volatile and PHM2 coke,the active hydrogen radicals and other matters contained in Coal A volatile promoted the secondary reaction of PHM2 coke and the decomposition of sulfur-containing matters,which further lead to the reduction of sulfur content in PHM2 coke.When it came to the interactions between PHM2 volatile and Coal A coke,the comprehensive influence of reactions of active sulfur radicals in PHM2 volatile with active hydrogen radicals and alkaline matters in Coal A coke resulted in the increase of sulfur content in Coal A coke.