Influence Of Metamorphic Degree Of Bituminous Coal On The Carbonization Effect By Flash Joule Heating

The ultra-low ash bituminous coal with three different metamorphism degrees is used as a carbon source,flash Joule heating is used as a method combined with physical adsorption（BET）,scanning electron microscopy（SEM）,X-ray photoelectron spectroscopy（XPS）,fourier transform infrared（FTIR）,X-ray diffraction（XRD）,and Raman,metamorphism degree,compound,flash conditions were studied to investigate physicochemical properties of porous carbon of bituminous coal by flash Joule heating and the effect of adsorption properties of porous caron were tested.The ash content of bituminous coal was reduced by floating-settling primary and heavy liquid centrifugation,and the physical and chemical properties of the selected ultra-low ash bituminous coal were analyzed and the preparation conditions of porous coke by Joule thermal flash were explored.The specific surface area of low-metamorphic（HV）,medium-metamorphic（MV）and high-metamorphic（LV）bituminous coal samples of ultra-low ash is less than 2 m²·g^-1,and the surface contains a large amount of C element and a small amount of O element,as well as similar functional groups.In the Raman analysis of HV,MV and LV,the ratio of ID/IG peak area was 4.73,3.41 and 2.89,respectively,indicating that HV had the lowest degree of graphitization.When the carbon black ratio is 15%,the tube type is straight,the alkali-carbon ratio is 3:1,and K₂CO₃ is the activator,the porous carbon prepared with MV as the carbon source has the largest specific surface area.Using HV,MV and LV as carbon sources,the effects of metamorphism on physical and chemical properties of Coke flash porous charcoal of bituminous coal were investigated.With the increase of metamorphism,the graphitization degree of porous carbon is higher,and the content of C-C in C1s state is increased.At a flash voltage of160V,the degree of graphitization of porous carbon prepared by LV（LV-AC-160）is the highest（I_D/I_G=1.19）and at a flash voltage of 80V,the content of C-C in the C1s state of porous carbon prepared by LV（LV-AC-80）is the highest（72.93%）.With the decrease of metamorphism,the more developed the pore structure of porous carbon,the more C-O content in C1s state increases.At the flash voltage of 80V,the specific surface area,total pore volume and C-O content of the porous carbon（HCV-AC-80）prepared by HV were the highest（601.95m²·g-1,0.44cm²·g-1 and 17.38%）in the state of C1s.Using HV and LV mixed sample（HL）as carbon source,the effects of combination of high volatile and low volatile bituminous coal on physical and chemical properties of Joule thermal flash porous carbon were investigated.Compared with a single coal type HV,with the increase of LV incorporation,the degree of graphitization of porous carbon prepared by HL becomes larger and the content of C-C in C1s increases,but the pore structure of porous carbon prepared by HL is underdeveloped and the content of C-O in C1s decreases.These results indicate that although LV is beneficial to improve the lattice structure of porous carbon prepared by HL,it is not conducive to improve the pore structure of porous carbon prepared by HL.The adsorption properties of four porous charcoal on methylene blue dye wastewater were investigated.The results show that the adsorption process of the four kinds of bituminous coke thermal flash porous carbon is more consistent with the pseudo-second-order kinetic model and Langmuir isothermal model,and the higher the temperature,the more favorable the adsorption.At 40℃,the adsorption capacities can reach 338.98mg·g^-1,which indicated that the Coke thermal flash porous carbon of bituminous coal had a considerable application prospect in the treatment of dye wastewater.There are 31 figures,25 tables and126 references in the thesie.