The utilization of high-sulfur coal is becoming more urgent due to the excessive utilization of low-sulfur,high-quality coal resources,and sulfur removal from high-sulfur coal is the most important issue.This paper re...The utilization of high-sulfur coal is becoming more urgent due to the excessive utilization of low-sulfur,high-quality coal resources,and sulfur removal from high-sulfur coal is the most important issue.This paper reviews the speciation,forms and distribution of sulfur in coal,the sulfur removal from raw coal,the thermal transformation of sulfur during coal pyrolysis,and the sulfur regulation during coal-blending coking of high organic-sulfur coals.It was suggested that the proper characterization of sulfur in coal cannot be obtained only by either chemical method or instrumental characterization,which raises the need of a combination of current or newly adopted characterization methods.Different from the removal of inorganic sulfur from coal,the organic sulfur can only be partly removed by chemical technologies;and the coal structure and property,particularly high-sulfur coking coals which have caking ability,may be altered and affected by the pretreatment processes.Based on the interactions among the sulfur radicals,sulfur-containing and hydrogen-containing fragments during coal pyrolysis and the reactions with minerals or nascent char,regulating the sulfur transformation behavior in the process of thermal conversion is the most effective way to utilize high organic-sulfur coals in the coke-making industry.An in-situ regulation approach of sulfur transformation during coal-blending coking has been suggested.That is,the high volatile coals with an appropriate releasing temperature range of CH4 overlapping well with that of H2 S from high organic-sulfur coals is blended with high organic-sulfur coals,and the C–S/C–C bonds in some sulfur forms are catalytically broken and immediately hydrogenated by the hydrogencontaining radicals generated from high volatile coals.Wherein,the effect of mass transfer on sulfur regulation during the coking process should be considered for the larger-scale coking tests through optimizing the ratios of different coals in the coal blend.展开更多
The low to medium-rank Tertiary coals from Meghalaya,India,are explored for the first time for their comprehensive micro-structural characterization using the FTIR and Raman spectroscopy.Further,results from these coa...The low to medium-rank Tertiary coals from Meghalaya,India,are explored for the first time for their comprehensive micro-structural characterization using the FTIR and Raman spectroscopy.Further,results from these coals are compared with the Permian medium and high-rank coals to understand the microstructural restyling during coalification and its controls on hydrocarbon generation.The coal samples are grouped based on the mean random vitrinite reflectance values to record the transformations in spectral attributes with increasing coal rank.The aliphatic carbon and the apparent aromaticity respond sharply to the first coalification jump(R:0.50%)during low to medium-rank transition and anchizonal metamorphism of the high-rank coals.Moreover,the Raman band intensity ratio changes during the first coalification jump but remains invari-able in the medium-rank coals and turns subtle again during the onset of pregraphitization in high-rank coals,revealing a polynomial trend with the coal metamorphism.The Rock-Eval hydrogen index and genetic potential also decline sharply at the first coalification jump.Besides,an attempt to comprehend the coal microstructural controls on the hydrocarbon poten-tial reveals that the Tertiary coals comprise highly reactive aliphatic functionalities in the type I-S kerogen,along with the low paleotemperature(74.59-112.28℃)may signify their potential to generate early-mature hydrocarbons.However,the presence of type II-II admixed kerogen,a lesser abundance of reactive moieties,and overall moderate paleotemperature(91.93-142.52℃)of the Permian medium-rank coals may imply their mixed hydrocarbon potential.Meanwhile,anchizonal metamorphism,polycondensed aromatic microstructure,and high values of paleotemperature(~334.25 to~366.79℃)of the high-rank coals indicate a negligible potential of producing any hydrocarbons.展开更多
The accumulation of coal gangue(CG)from coal mining is an important source of heavy metals(HMs)in soil.Its spatial distribution and environment risk assessment are extremely important for the management and remediatio...The accumulation of coal gangue(CG)from coal mining is an important source of heavy metals(HMs)in soil.Its spatial distribution and environment risk assessment are extremely important for the management and remediation of HMs.Eighty soil samples were collected from the high-sulfur CG site in northern China and analyzed for six HMs.The results showed that the soil was heavily contaminated by Mn,Cr and Ni based on the Nemerow index,and posed seriously ecological risk depended on the geo-accumulation index,potential ecological risk index and risk assessment code.The semi-variogram model and ordinary kriging interpolation accurately portrayed the spatial distribution of HMs.Fe,Mn,and Cr were distributed by band diffusion,Ni was distributed by core,the distribution of Cu had obvious patchiness and Zn was more uniform.The spatial autocorrelation indicated that all HMs had strong spatial heterogeneity.The BCR sequential extraction was employed to qualify the geochemical fractions of HMs.The data indicated that Fe and Cr were dominated by residual fraction;Cu,Ni and Zn were dominated by reducible and oxidizable fractions;Mn was dominated by reducible and acid-extractable(25.38%-44.67%)fractions.Pearson correlation analysis showed that pH was the main control factor affecting the non-residue fractions of HMs.Therefore,acid production from high sulfur CG reduced soil pH by 2-3,which indirectly promoted the activity of HMs.Finally,the conceptual model of HMs contamination at the CG site was proposed,which can be useful for the development of ecological remediation strategies.展开更多
Preliminary sink-float experiments on high-sulfur coal was done in some mining areas and carried on elementary analysis, industrial analysis, and ashcontent analysis. Through the experiments, definite middlings, and g...Preliminary sink-float experiments on high-sulfur coal was done in some mining areas and carried on elementary analysis, industrial analysis, and ashcontent analysis. Through the experiments, definite middlings, and gangue, the phase analysis of sulfur was carried on, by which a good understanding of sulfur characters in raw coal was achieved.展开更多
基金financial support of National Natural Science Foundation of China(U1910201,21878208)Transformation of Scientific and Technological Achievements Programs of Higher Education Institutions in Shanxi(TSTAP)Shanxi Province Science Foundation for Key Program(201901D111001(ZD))。
文摘The utilization of high-sulfur coal is becoming more urgent due to the excessive utilization of low-sulfur,high-quality coal resources,and sulfur removal from high-sulfur coal is the most important issue.This paper reviews the speciation,forms and distribution of sulfur in coal,the sulfur removal from raw coal,the thermal transformation of sulfur during coal pyrolysis,and the sulfur regulation during coal-blending coking of high organic-sulfur coals.It was suggested that the proper characterization of sulfur in coal cannot be obtained only by either chemical method or instrumental characterization,which raises the need of a combination of current or newly adopted characterization methods.Different from the removal of inorganic sulfur from coal,the organic sulfur can only be partly removed by chemical technologies;and the coal structure and property,particularly high-sulfur coking coals which have caking ability,may be altered and affected by the pretreatment processes.Based on the interactions among the sulfur radicals,sulfur-containing and hydrogen-containing fragments during coal pyrolysis and the reactions with minerals or nascent char,regulating the sulfur transformation behavior in the process of thermal conversion is the most effective way to utilize high organic-sulfur coals in the coke-making industry.An in-situ regulation approach of sulfur transformation during coal-blending coking has been suggested.That is,the high volatile coals with an appropriate releasing temperature range of CH4 overlapping well with that of H2 S from high organic-sulfur coals is blended with high organic-sulfur coals,and the C–S/C–C bonds in some sulfur forms are catalytically broken and immediately hydrogenated by the hydrogencontaining radicals generated from high volatile coals.Wherein,the effect of mass transfer on sulfur regulation during the coking process should be considered for the larger-scale coking tests through optimizing the ratios of different coals in the coal blend.
文摘The low to medium-rank Tertiary coals from Meghalaya,India,are explored for the first time for their comprehensive micro-structural characterization using the FTIR and Raman spectroscopy.Further,results from these coals are compared with the Permian medium and high-rank coals to understand the microstructural restyling during coalification and its controls on hydrocarbon generation.The coal samples are grouped based on the mean random vitrinite reflectance values to record the transformations in spectral attributes with increasing coal rank.The aliphatic carbon and the apparent aromaticity respond sharply to the first coalification jump(R:0.50%)during low to medium-rank transition and anchizonal metamorphism of the high-rank coals.Moreover,the Raman band intensity ratio changes during the first coalification jump but remains invari-able in the medium-rank coals and turns subtle again during the onset of pregraphitization in high-rank coals,revealing a polynomial trend with the coal metamorphism.The Rock-Eval hydrogen index and genetic potential also decline sharply at the first coalification jump.Besides,an attempt to comprehend the coal microstructural controls on the hydrocarbon poten-tial reveals that the Tertiary coals comprise highly reactive aliphatic functionalities in the type I-S kerogen,along with the low paleotemperature(74.59-112.28℃)may signify their potential to generate early-mature hydrocarbons.However,the presence of type II-II admixed kerogen,a lesser abundance of reactive moieties,and overall moderate paleotemperature(91.93-142.52℃)of the Permian medium-rank coals may imply their mixed hydrocarbon potential.Meanwhile,anchizonal metamorphism,polycondensed aromatic microstructure,and high values of paleotemperature(~334.25 to~366.79℃)of the high-rank coals indicate a negligible potential of producing any hydrocarbons.
基金supported by the National Key R&D Program of China (No.2019YFC1805001)Open Foundation of State Key Laboratory of Mineral Processing (No.BGRIMM-KJSKL2022-07)。
文摘The accumulation of coal gangue(CG)from coal mining is an important source of heavy metals(HMs)in soil.Its spatial distribution and environment risk assessment are extremely important for the management and remediation of HMs.Eighty soil samples were collected from the high-sulfur CG site in northern China and analyzed for six HMs.The results showed that the soil was heavily contaminated by Mn,Cr and Ni based on the Nemerow index,and posed seriously ecological risk depended on the geo-accumulation index,potential ecological risk index and risk assessment code.The semi-variogram model and ordinary kriging interpolation accurately portrayed the spatial distribution of HMs.Fe,Mn,and Cr were distributed by band diffusion,Ni was distributed by core,the distribution of Cu had obvious patchiness and Zn was more uniform.The spatial autocorrelation indicated that all HMs had strong spatial heterogeneity.The BCR sequential extraction was employed to qualify the geochemical fractions of HMs.The data indicated that Fe and Cr were dominated by residual fraction;Cu,Ni and Zn were dominated by reducible and oxidizable fractions;Mn was dominated by reducible and acid-extractable(25.38%-44.67%)fractions.Pearson correlation analysis showed that pH was the main control factor affecting the non-residue fractions of HMs.Therefore,acid production from high sulfur CG reduced soil pH by 2-3,which indirectly promoted the activity of HMs.Finally,the conceptual model of HMs contamination at the CG site was proposed,which can be useful for the development of ecological remediation strategies.
文摘Preliminary sink-float experiments on high-sulfur coal was done in some mining areas and carried on elementary analysis, industrial analysis, and ashcontent analysis. Through the experiments, definite middlings, and gangue, the phase analysis of sulfur was carried on, by which a good understanding of sulfur characters in raw coal was achieved.
