Study On The Maceral Crushing And Liberation And On The Coal Blending Coking For Gas Coal

China is rich in coal resources,but coal type is unevenly distributed.The shortage of high quality coking coal will be the main bottleneck restricting the development of China's coking and metallurgical industry in the future.It is of great significance to the development of China's coking industry,economic and long-term planning to explor methods and techniques to expanding coking coal resources.It will be a possible way to expland coking coal resources to the realization of coal utilization by the use of concentrates with different coal macreals obtained by the seperation technology of maceras which based on the different properties of macerals.With the long flame coal of ShenDong,gas coal of DongHuantuo,fat coal of Qian Jiaying,and coking coal of LvJiatuo as the research object,this article systematically studied the mechanical properties,crushing behavior,dissociation characteristics and separation effects of different particle size from different rank coal maceral;This article also studied coking properties,dilatation,thermal behavior,different pyrolysis temperature of the solid product microstructure,microstructure and crystalline structure from different gas maceral concentrates;This paper studied coke characteristics from different gas coal maceral concentrates individually This paper studied laws of cake cold strength,thermal properties,pore structure,microstructure and crystal structure the with additive amount of gas coal reactives when gas coal rich-vitrinite and rich-inertinite concentrates respectively in coal blending for coking.The main conclusions as follows:1 Study on crushing and dissociation of macerals(1)The study of the mechanical properties of macerals show that,the microhardness and microbrittleness and HGI of the vitrinite and the inertinite increase gradually with the increase of coal rank;To Long flame coal,the microbrittleness and HGI of vitrinite are lower than that of inertinite.To gas coal and fat coal,the microbrittleness and HGI of vitrinite are higher than that of inertinite.(2)The study of crushing of macerals show that,for Long flame coal,the inertinite is brittle and fragile,and tends to enrich in coarse product when crushing,while vitrinite is opposite;For gas coal and fat coal,the vitrinite is brittle and fragile,and tends to enrich in the fine product when crushing,while inertinite is opposite.(3)The study of maceral dissociation show that,the free fraction of maceral gradually increase with decrease of crushing size;the optimum liberation size are 0.125 mm,0.074 mm and 0.074 mm for long flame coal,gas coal and fat coal,when 85% degree of dissociation of useful minerals as the standard.While the corresponding vitrinite optimum liberation size are 91.88%,91.42% and 90.77%,the inertinite optimum liberation size are 86.77%,87.81% and 61.78% respectively.(4)The study of maceral separation show that,the recovery and purity of vitrinite increase in low density products with the decrease of crushing size;the recovery rate of vitrinite was 58.73%,58.50% and 61.19%,and vitrinite concent was 86.05%,89.52% and 90.54% for long flame coal,gas coal and fat coal when the vitrinite concentrates is the product with density below 1.33kg/l.2 Study on the properties of gas coal maceral concentrates(1)The study on coking property and dilatation of maceral concentrates show that,the coking index and the quality and size of net structure increase with the increase of the amount of reactives.The relation between macerals and total dilatation is determined,the maximum capacity of inertinite for gas coal reactives is 16.19%.(2)The study on thermal behavior show that,the process of coking coal mainly includes drying desorption stage,pyrolysis initial stage,bound formation stage and semicoke polycondensation stage.The thermal weightlessness mainly focus on the stage of bound formation.The higher the amount of reactives,the greater the proportion of weightlessness.With the decrease of the reactives,the Ti and Tmax decrease,and Tf shifted to the high temperature,the TG curve decreased gradually,and the DTGmax decreased gradually.The dynamics show that the activation energy of the concentrates is from 68.43 kJ·mol-1 to 76.81 kJ·mol-1,when the amount of reactives is from 65.63% to 91.11%.(3)The study on structure of concentrates pyrolysis product show that,there are more aliphatic structure in the pyrolysis product of DQ1 and more aromatic structure in the produce of DQ3,when temperature under 450?.There is no difference of structure for all the products when up 550?.(4)The study on optical texture of concentrates pyrolysis product show that,Below 350?,there is no obvious change in reflectance and surface for vitrinite and inertinit.When 350-550?,the vitrinite particles softening and melting and form pore structure,the reflectance of vitrinite and inertinite obviously increase.When 550-750?,the reflectance of vitrinite and inertinite rapidly increase to 5%,the vitrinite transform mainly into isotropic texture and lightly into fine mosaick,the inertinite transform mostly into fragments and filaments.When 750-900?,the optical texture is no longer change,the reflectance increase to 6.5%.The amount of metaplast adhered to the surface of inertinite increased gradually with the increase of the amount of reactives in concentrates,when up 550?.(5)The study on microcrystalline structure of concentrates pyrolysis product show that,the development of microcrystalline structure is mainly based on longitudinal joint growth,when below 650?.The inner formation of aromatic lamellae gradually increase,when up 650?.The higher the amount of reactives in the concentrates,the greater the Lc and La of the pyrolysis products,the smaller the d002.(6)The study on coke quality carbonized by single coal with different amount of reactives show that,I10 and SSI and CRI of coke increase and MSI and CSR decrease gradually with the increase of the amount of reactives in concentrates.The main factors affecting the thermal properties of coke are optical structure and specific surface area,but the difference of the thermal properties of coke is caused by the difference of specific surface area.3 Study on coal blending and coking for gas coal maceral concentrates(1)The study on the effect of the additive amount of gas coal reactives on coke mechanical strength show that,the additive of rich-vitrinite and rich-inertinite degrade the mechanical strength of coke from fat coal and coking coal,and the deterioration degree is more for coke from coking coal.The amount additive gas coal reactives into unit mass base coal is the same,the degradation degree of coke I10 and SSI is smaller when adding DQ1,the degradation degree of coke MSI is small when adding DQ3.When I10 and SSI for coke from blended coal is close to coke from fat coal,the max-amount additive gas coal reactives into fat coal is 0.39 when DQ1 is added,the max-amount additive gas coal reactives into fat coal is 0.16 when DQ3 is added;When MSI for coke from blended coal is close to coke from fat coal,the max-amount additive gas coal reactives into fat coal is both 0.10 when DQ1 and DQ3 is added.The mechanical strength evenly decrease when gas coal is added,and there is no degradation point.(2)The study on the effect of the additive amount of gas coal reactives on coke thermal property show that,the additive of rich-vitrinite and rich-inertinite degrade the thermal property of coke from fat coal and coking coal,the thermal property change evenly with the increase of gas reactives added in fat coal and coking coal,and there is no degradation point,and the deterioration degree is more for coke from coking coal.The amount additive gas coal reactives into unit mass base coal is the same,the degradation degree of coke thermal property is smaller when adding DQ3.(3)The study on the effect of the additive amount of gas coal reactives on coke pore structure show that,the porosity and average pore diameter of coke increased gradually,and the pore size distribution shifted to the direction of large pores,and the average thickness of the pore wall decreased gradually,and the specific surface area of coke increased firstly and then decreased with the amount of gas coal reactives added into unit mass fat coal or coking coal increase.The amount additive gas coal reactives into unit mass base coal is the same,the degradation degree of coke porosity and average pore diameter is more significant when adding DQ3,the degradation degree of coke average thickness of the pore wall and the specific surface area is more significant when adding DQ1.When porosity and average pore diameter for coke from blended coal is close to coke from fat coal,the max-amount additive gas coal reactives into fat coal is 0.39 and 0.22,when DQ1 and DQ3 is added respectively.The change of coke porosity and average pore diameter is the main cause of deterioration of coke SSI,which provides for the relationship between SSI and MSI and CRI change with the amount of coal active coke interpretation.(4)The study on the effect of the additive amount of gas coal reactives on coke optical texture show that,the degree of anisotropy decreases gradually with the amount of gas coal reactives added into unit mass coal increase,which provides an explanation for the relationship between the CRI and the amount of gas reactives.The additive gas coal reactives is the same,the degradation degree of coke degree of anisotropy is more significant when adding DQ3.Coking with gas coal and fat coal,fat coal have an modification on gas coal,which promoting the development of anisotropic microstructure of coke,insulting OTI>OTIweighted,ISO<ISOweighted.Coking coal have no modification on gas coal.(5)The study on the effect of the additive amount of gas coal reactives on coke microcrystalline structure show that,the additive of rich-vitrinite and rich-inertinite degrade the microcrystalline structure of coke from fat coal and coking coal,and the deterioration degree is more for coke from coking coal.The amount additive gas coal reactives into unit mass base coal is the same,the degradation degree of coke microcrystalline structure is smaller when adding DQ3.When La?Lc and d002 for coke from blended coal is close to coke from fat coal,the max-amount additive gas coal reactives into fat coal is 0.39 and 0.16 when DQ1 and DQ3 is added respectively.The mutation point is same or close between microcrystalline structure and thermal property,which indicate that the change of the microcrystalline structure of coke is one of the factors that cause the change of coke thermal property.(6)The cause of SSI degradation is the change of porosity and average pore diameter;the cause of MSI deterioration is the change of coke optical texture and pore wall thickness;the cause of thermal properties deterioration is the change of surface area,optical structure and crystal structure.