Study On The Properties Of The Thermal Dissolution Of Xilinguole Lignite And The Use Of Their Tdsfs In The Coal Blending For Coke-making

In this paper, the effect of thermal dissolution(TD) temperature and solvent on the TD property of Xilinguole lignite(XLGL), 1/3 coking coal were compared, and the structure and composition of TD soluble fraction(TDSF) were characterized by TG-DTG curve, FT-IR, elemental analysis, dynamic viscoelastic and acidic functional groups determinations. At the same time, TD insoluble fraction( TDIF) in coal blending for coke-making on the quality of coke was investigated, and the relation between the coal structure, composition and the caking and coking ability was revealed in this thesis.Experimental results show that ash in coal can be removed by TD. TD temperature play a significant effect on the TD properties of XLGL lignite, and too high or low of TD temperature is disadvantage to the TD of XLGL lignite. In non polar solvent 1- methyl naphthalene(1-MN), the TD yield of XLGL lignite got the highest of 45.8% at 360 ?. Solvent also has influences to the TD of XLGL lignite.1-methylnaphthalene + 10% methanol(1-MN+10%MT) gave highest TD yield of79.8%. CMNO was the next and 1-MN gave the minimum TD yield. Polar solvent gave better TD properties to XLGL lignite than non polar solvent at 360?. Addition of methanol in 1-MN, the TD yield of XLGL lignite increased significantly, and also was for CMNO, which increased about 10% at 360 ?. The reason that 1-MN+10%MT gave high TD yield may be the result of alcoholysis reaction of methanol and the structure of-OH. With the increase of the polarity of the solvent, the destruction to large molecular structure of coal by solvent is strong, and more heavy components with aromatic hydrocarbon structure are extracted. But the TD yield of 1/3 coking coal increased gradually with temperature rising, and the highest TD yield of 75.6%was obtained in non polar solvent1-MN at 380?. The TD yields in 1-MN with 10%methanol and CMNO were all lower than that in 1-MN, they decreased by 12.9%,4.8% respectively. This may be because that the polar solvent is disadvantage to breakthe association structure of coal, resulting in the decrease of TD yield.Dynamic viscoelastic measurement of TDSF suggest that the softening temperature of TDSF of XLGL lignite obtained in 1-MN at 340? gave the minimum value. This is because with increase of TD temperature, more heavy components with aromatic hydrocarbon structure which is difficult to volatile and to decompose, were extracted and enter into TDSF, resulting in the increase of softening temperature.Softening temperature of TDSF from CMNO at 360 ? is minimum, and the temperature range of thermoplasticity is widest, indicating that The TDSF of CMNO contains more small molecular compounds. The TDSF from 1/3 coking coal in 1-MN at 360 ? gave the lowest softening temperature and the highest solidification temperature, therefore the temperature range of thermoplasticity is the widest. The TDSF in 1-MN+10%MT gave the highest softening temperature and the narrowest temperature range of thermoplasticity. The longer the TDSF keeps in thermoplasticity,the better improvement it to the coke-making quality.Effects of addition of different TDSFs from XLGL lignite, 1/3 coking coal on the quality of coke suggest that addition of TDSF of XLGL lignite in coke-making, with TD temperature rising, quality of cokes obtained gradually decreased, but they were still higher than the quality of coke from standard coal blends. Adding TDSF from TD in CMNO at 360? the reactivity of coke decreased about 16.2%, PSR and MSI0.2improved significantly. The TDSF from CMNO gave the best improvement to the quality of coke, and those from 1-MN+10%MT and 1-MN were next and the worst respectively. Addition of TDIF of XLGL lignite does not have improvement to the quality of coke, but the quality of coke is higher than the quality of coke with addition of XLGL raw coal, suggesting that TD have significant modification to the low rank coal. The improvement effects of TDSFs of 1/3 coking coal obtained from different solvents at same conditions on the quality of coke are different. The TDSF from1-MN gave the best improvement, and those from CMNO and 1-MN+10%M were next and the worst. The improvement effects to the quality of coke by the TDSF in1-MN from 1/3 coking coal were higher than that from XLGL lignite, while those in CMNO and 1-MN+10%MT from 1/3 coking coal were lower than those from XLGL lignite.