合成气气氛/复合溶剂系统下褐煤液化制油及机理研究

Because of the abundance of lignite reserves in our country, developing liquefaction technologies for conversion of lignite to oils is very significant for the energy security of our country and the efficient utilization of lignite resource. Based on deep considerations of the technical properties of lignite and the chemical and physical processes of direct coal liquefaction, the project proposes the liquefaction technology for conversion of lignite to oils under syngas atmospheres (CO+H2) and complex solvents (H2O+organic solvent), which is a new technology with industrialization prospect. Till now, the understandings on the process and mechanism of lignite liquefaction (especially, the actions of CO and H2O on the liquefaction process) under the proposed system are not enough deep. Besides, the studies on the liquefaction catalysts under this proposed system are also so. Therefore, the study on liquefaction process and mechanism for conversion of lignite to oils under syngas atmospheres and complex solvents is proposed, and its main research contents are planned as follows: the effects of main technical conditions on the conversion effectiveness of lignite to oils, the effects and action mechanisms of CO and H2O on the lignite liquefaction process, and the effects of catalysts with different functions on the lignite liquefaction hehaviors. The study with obvious innovations can provide not only the theoretical foundation for the further devolopment and optimization of the lignite liquefaciton technolgoy under this proposed system, but also the reference for the efficient utilization of the bulk lignite resources. The previously pertinent researches can make a firm foundation for the implement of this project.

我国褐煤资源丰富，开发褐煤液化制油技术对我国的能源安全保障和褐煤资源的有效利用具有重要意义。本项目针对褐煤的工艺性质特点，在深入分析煤直接液化化学和物理过程的基础上，提出了合成气气氛(CO+H2)/复合溶剂(H2O+有机溶剂)系统下褐煤液化制油新技术，具有工业化前景。目前，有关本系统下褐煤液化反应及过程机理的认识不够(特别是本系统中CO和H2O对该过程作用)；对本系统下所需催化剂的认识也不够。为此，本项目拟开展本系统下褐煤液化制油及机理的研究，主要围绕以下三个方面的内容： 主要工艺条件对褐煤转化为油的效果；CO和H2O对褐煤液化过程的影响及作用机理；不同功能催化剂对褐煤液化行为的影响。这项研究有明显创新性，不仅可为本系统下褐煤液化技术的进一步开发和优化提供理论基础，而且可为庞大褐煤资源的有效利用提供参考。与本研究有关的前期工作为本项目奠定了坚实基础。

我国褐煤资源丰富，开发褐煤液化制油技术对我国的能源安全保障和褐煤资源的有效具有重要意义。本项目针对褐煤的工艺性质特点，在深入分析煤直接液化化学和物理过程的基础上，提了合成气气氛(CO+H2)/复合溶剂(H2O+有机溶剂)系统下褐煤液化制油新技术，极具工业化前景。本项目以褐煤为原料，探讨主要工艺条件下褐煤转化为油的效果，CO和H2O对褐煤液化过程的影响及作用机理，以及不同功能催化剂对褐煤液化行为的影响。获得一些重要认识，如：相同反应条件下，(H2+CO)/(THN+H2O)体系胜利褐煤液化转化率和油产率显著高于传统H2/THN体系，同时(H2+CO)/(THN+H2O)体系胜利褐煤液化氢气耗量较低，合成气气氛替代纯氢气气氛用于煤液化工艺有一定的可行性。在该系统中水煤气变换反应的发生可以在一定程度上提高煤的转化率与油气水产率，但当含水量过高时，不但导致了气相与溶剂的供氢能力降低，还使沥青烯与前沥青烯发生缩聚，导致液化性能明显降低。该体系中，不添加催化剂水煤气变换反应程度较低，添加碱金属、铁系催化剂均能提高液化系统中水煤气变换反应活性，从而促进活性氢的产生。CO在煤液化过程中起到一定的作用，CO可以与煤结构反应造成了煤结构的裂解；另一方面发生水煤气变换反应产生活性氢，稳定煤裂解自由基，提高煤液化转化率。系统中的水与褐煤形成交互作用，-OH与煤中的苯环结构结合，从而起到弱供氢作用，导致煤中酸性基团浓度和氢、氧元素含量增加，后期褐煤转化率和油产率增加。该系统下液化过程中Na (K) 系催化剂可促进煤中醚键断裂，铁系催化剂形成活性相Fe1-xS能促进煤的裂解加氢，提高油产率。上述研究成果进一步认识了该系统下褐煤液化过程，不仅可为合成气气氛/复合溶剂系统下的褐煤液化制油技术的开发和优化提供理论基础，而且可为庞大褐煤资源的有效利用提供参考。