小龙潭褐煤不同气氛下液化性能的研究

根据褐煤含水量高的特点，研究了以水为溶剂，不同气氛条件下小龙潭褐煤的液化行为。结果表明，小龙潭褐煤具有较好的液化活性，在420℃，H₂气氛下以四氢萘为溶剂时煤的液化转化率可达到94.5%。煤液化过程中，稳定热解产生的自由基活性氢主要来自于供氢溶剂，而气相H₂不具活性，不能直接为液化过程提供活性氢。当以水为溶剂取代四氢萘进行褐煤直接液化时，相对于H₂和N₂气氛，CO 气氛下表现出较好的液化性能。这表明发生了水煤气变换反应并生成了活性氢，该活性氢可以使得煤热解产生的自由基稳定，生成低分子的液化产物，提高了液化转化率。由于在较低的CO初压下反应生成的活性氢数量有限，因而液化转化率不高。实验表明，以水为溶剂在CO气氛下进行褐煤的液化是一种新的褐煤直接液化技术。

Preliminary study on liquefaction properties of Xiaolongtan lignite under different atmospheres

The liquefaction properties and mechanism of Xiaolongtan (XLT) lignite were studied. On the basis of high content of water in lignite, the liquefaction behavior of XLT lignite under different atmospheres using water as solvent was preliminarily probed. The results show that XLT lignite has a good liquefaction activity, and its liquefaction conversion gets to 94.5% at 420°C, H₂ atmosphere, and tetralin (THN) used as solvent. During coal liquefaction, the active H stabilizing free radicals formed during coal pyrolysis is mainly from hydrogen donor solvent. H₂ Gas has no hydrogenation activity, and it cannot directly provide active H for coal liquefaction. When water was used as solvent instead of THN in liquefaction of XLT lignite, high liquefaction conversion occurs under CO atmosphere compared to H₂ or N₂ atmosphere. This suggested that the water gas shift reaction produced active H under CO atmosphere. The active H stabilized the free radicals formed from coal pyrolysis to form lower molecular weight liquefaction products, and therefore, increasing liquefaction conversion. Because of the low primary pressure of CO in the experiment, the active H formed from the water gas shift reaction is limited. Thus, the liquefaction conversion of XLT lignite is not high when water is used as solvent. But our preliminary study shows that it is new lignite liquefaction technology using water as solvent under CO atmosphere and has remarkable market value and utilization prospects.