Wet Entrained Flow Gasification Of Coal Liquefaction Residue Application

Direct coal liquefaction is a way of efficient use of coal and it belongs to the clean coal utilization technologies.However, the direct coal liquefaction is not only bring the liquid oil to us, at the same time, it also generate a large amount of liquid residue can not be reasonably used and this situation limits the direct coal liquefaction technology in popularization and use. In this thesis, two materials, Shenhua and Gansu coal liquefaction residue, were chosen for the study objects and the slurry idiosyncrasy with gasification results of the residue slurry were identified as the two important investigation focuses, the feasibility of the coal liquefaction residues as raw materials for the wet entrained flow gasification is explored.In the slurry preparation side, Shenhua Coal Liquefaction residues can not be directly prepared to the slurry of high concentration, high stability and high fluidity. Under the condition of add the additive which was selected in the test, the residue slurry concentration can be reached to 76% (wt%)and the slurry were non-Newtonian pseudoplastic fluid, this characteristics including the stability and liquidity of the slurry are all in line with the requirements of material which the wet entrained flow gasification required. Appropriate amount of additives added is 0.5% (wt%, residue basis).Reasonable size segment can restrictedly improve the slurry concentration.In the gasification area, Shenhua coal liquefaction residue has high C and H elements content and high heat energy. The effective gas content of syngas which obtained by 70% (wt%) concentration of the slurry gasification is 86.87% (vol%), the carbon conversion rate reaches to 98.38% (wt%), the consumption of raw materials is 537 kg/KNm3(CO+H2), the oxygen consumption is 376 Nm3/KNm3(CO+H2) and the cold gas efficiency is 76.39%.All of the results are better than the effect which after the 60% of the concentration slurry of Shenhua raw coal gasification. The volume content of H2, the consumption of raw materials and the oxygen consumption are increased with the concentration of slurry reduced, but the CO volume fraction, the total volume fraction of effective gas and cold gas efficiency are all increased with the concentration of the slurry increased. The CH4 content in the syngas is reduced with the gasification temperature increased.In the case of no additive joined, Gansu coal liquefaction residue can not be cranked out high concentration, high stability and high fluidity slurry too.After adding suitable additives that through the test select and determining the appropriate amount of additives (0.5%,wt%, residue-based), the concentration of the slurry prepared by residue is 78%(wt%), both the stability with the liquidity are good and the slurry is non-Newtonian pseudoplastic fluid, all the performances of the slurry are fully meet the requirements of raw materials which the entrained flow gasification needed. As the gasification feedstock, Gansu coal liquefaction residue has lower C and H elemental content and has lower heat energy, higher ash content than Shenhua Coal Liquefaction residues. Affected by these factors, the effective gas content of syngas which obtained by 72%(wt%) concentration of the slurry gasification is 80.96% (vol%),the carbon conversion rate is 92.57%(wt%), the consumption of raw materials is 847kg/KNm3(CO+H2), the oxygen consumption is 430Nm3/KNm3 (CO+H2) and the cold gas efficiency is low, only reaches to 69.33%.All the index of gasification are bad than the gasification results which obtained by 60% concentration slurry of Gansu raw coal except the oxygen consumption. The same situation to the Shenhua coal liquefaction residues gasification, the volume content of H2 in syngas, the material consumption and the oxygen consumption are reduced when the slurry concentration increased, while the volume content of CO, the total effective gas volume fraction and cold gas efficiency data are increased.