Study On The Effect Of TDSFs Of Lignite And Fat Coal Blending For Coke-making On Coke Quality

In the thesis,the thermal dissolutions(TDs)of Xilinguole lignite(HM)and fat coal wasstudied,and the TDs properties of the two kinds of coal under different solvents wasexplored.The composition and structure of the thermal dissolution soluble fraction(TDSF)was characterized by FT-IR,ultimate analysis,rheometers,TG,scanning electron microscope(SEM)and ~1H-NMR,and the law of TDs was explored.The effect of TDSF on coke quality was studied by adding TDSF to blend coal for coking.The results show that the TD process of different rank coal is significantly affected by solvents,and FM with higher rank has higher thermal dissolution yield(TDY)than low-rank HM.In addition,the difference of polarity and structure of solvents can also significantly change the TD effect.For HM the highest TDY of 44.8%was obtained in polar solvent 1-MN+MT,and the highest TDY of FM was 79.3%,which was obtained in polar solvent CMNO.The components of TDSFs from HM were also different from those from FM.The H/C ratio of TDSFs from HM was high,and it mainly consisted of aliphatic hydrocarbons with certain amount of aromatic structure and oxygen functional groups.TDSFs from FM mainly consisted of aliphatic hydrocarbons with high degree of substitution and low degree of branching.They contained a large number of aromatic structures and a small amount of oxygen-containing functional groups,and the effect of TD on the structure of TDSF from was more significatly.The dynamic viscoelasticity and caking properties of the TDSFs from two coals were measured.It was found that the caking properties of TDSFs from HM were significantly enhanced compared with that of raw coal.For the TDSFs from the same coal,with the softening temperature of TDSF decreasing the G increased.The structure analysis showed that the aromaticity and degree of substitution of the TDSFs were different,and the degree of side chain and branched chain were also quite different.The aromaticity of TDSF from HM is generally low,only 0.63 or 0.62.The structure of TDSF from HM was mainly aliphatic hydrocarbon with high degree of substitution and branching.The degree of metamorphism and condensation of aromatic ring for FM are high.After TD,the aromaticity of TDSF from FM reduced to 0.65,which is close to TDSF from HM,and the degree of substitution was increased.The TDSF from FM mainly consisted of aliphatic hydrocarbon,and the degree of branching also increased.Generally speaking,the difference of TDSF structure between the two coals is smaller compared to that of their raw coal.Just like the TDSF from FM,it is found that the TDSF from HM can produce liquid plastic mass during pyrolysis and coking,thus increasing the caking property and thermoplasticity of the blending coal,improving the interface bonding state of semi-coke,and the quality of coke.Among them,the TDSFs of HM-CMNO and FM-1-MN had the best effect,PRI decreased by 4.9%and 3.4%respectively,CSR increased by10.8%and 6.8%respectively,and MSI 0.2 increased by 9.2%and 5.5%respectively,because of their low aromaticity,large amount of aliphatic hydrocarbons and side chain alkanes with high branching degree,which can produce a large amount of plastic mass in the thermoplastic stage,thus improving the quality of coke.Under the same conditions,the coke quality of TDSF from FM was better than that of TDSF from HM,because the distribution of active components in TDSF from FM was wide.The coke quality can be improved by adding TD treated HM in coal blending compared to that adding HM itself,while the TDIF has no obvious effect on improving the quality of coke.That is to say,the TD process can improve the caking properties of HM to a certain extent.The volatile matter of coal is negatively correlated with its coke yield.With the volatile matter of blended coal increasing the coke yield decreased.