胜利褐煤水蒸气气化制富氢合成气及其固有矿物质的催化作用

Production of hydrogen-rich syngas by steam gasification of Shengli lignite and catalytic effect of inherent minerals

利用微型固定床反应装置,研究了内蒙古胜利褐煤水蒸气气化过程中H2、CO2、CO和CH4生成规律及其固有矿物质的催化效应。原煤(SL-raw)、盐酸洗脱(SL-HCl)、氢氟酸洗脱(SL-HF)及盐酸洗脱液回添煤样(SL-HCl-Re)在水蒸气气化反应过程中,H2、CO2和CO生成速率存在明显差异,充分说明胜利褐煤中某些固有的矿物质对其水蒸气气化反应具有显著的催化作用,可大幅度提高其气化反应速率,并使其起始气化温度降低96℃,气化反应主体温度降低150℃以上,同时促进了合成气中H2生成,抑制了CO的生成,使胜利褐煤水蒸气气化反应过程中一直维持着较高的H2/CO摩尔比,SL-raw、SL-HCl-Re水蒸气气化所得合成气中H2/CO摩尔比分别为17.3和4.3,而SL-HCl和SL-HF水蒸气气化所得合成气中H2/CO摩尔比均只有1.22。SL-HCl和SL-HF水蒸气气化生成H2、CO2和CO的规律基本相同,说明起催化作用的物质是可溶解在盐酸洗脱液中的矿物质。经过分析,发现矿物质对胜利褐煤水蒸气气化反应的催化作用主要是通过提高水煤气变换反应(WGSR)速度实现的。最后结合文献报道提出了胜利褐煤水蒸气气化反应过程中矿物质的原位催化机理。

The temperature programmed steam gasification and isothermal steam gasification （TPSG and ISG） of Shengli lignite were studied on a fixed-bed micro-reactor equipment. The TPSG results suggested that some inherent minerals effectively improved steam gasification of Shengli lignite. The initial reaction temperature and gas-reaction temperature for steam gasification decreased by about 96℃ and 150℃, respectively, when the mineral elements were retained in the lignite. The minerals in the lignite which were assumed to be catalysts aiding the lignite-steam gasification could be separated with hydrochloric acid. The effect of different acid treatments of the lignite on steam gasification was also studied. The H2/CO molar ratio in the syngas produced from the steam gasification of raw lignite （SL-raw） and the lignite back- added with HC1 eluate （SL-HC1-Re） were as high as 17.3 and 4.3, respectively, but it was only 1.22 for the lignite treated with HC1 or HF. It was speculated that the enhanced steam gasification of Shengli lignite could be attributed to the promotion effect of inherent minerals on water-gas shift reaction （WGSR）. Finally, the possible in-situ catalytic mechanism of inherent minerals in Shengli lignite for steam gasification reaction was suggested.