甲醇水蒸气重整与煤热解耦合制油过程研究

Coal pyrolysis for tar production is one of the most important utilization technologies of coal. This proposal intends to explore a new method for clean coal conversion by integrating the coal pyrolysis process with steam reforming of methanol (SRM), in which a large number of active intermediate and free radicals generated by SRM can stabilize the free radicals cracked by coal pyrolysis and prevent them from condensation, resulting in the increase of tar yield during coal pyrolysis. Catalysts for SRM will be prepared by impregnation and coprecipitation methods, and the effects of preparing technologies and reaction conditions on their catalytic performances will be investigated. After that, the preparing technologies of the catalysts will be optimized to compatible with process parameters of the integrated process by characterization and analysis. The pyrolysis properties and kinetics of the coal samples selected will be conducted to obtain the optimal parameters of coal pyrolysis for tar production. Then the SRM and coal pyrolysis process will be matched thought adjusting and optimizing the process parameters of both single processes, so that the effect of reaction conditions of the integrated process on tar yield could be systematically investigated. The relations between parameters of the integrated process and the distribution and composition of the products will be established by characterization of the products, and the parameters of the integrated process can be optimized accordingly so that the integrated process can proceed towards the direction of increasing tar yield and improving tar quality. The reaction mechanism of the integrated process will be discussed by steady-state isotope tracer method.

煤热解制取焦油是一种重要的煤炭分质转化利用技术。拟将甲醇水蒸气重整过程与煤热解制油过程耦合，利用甲醇水蒸气重整过程中产生的大量活性中间产物和自由基稳定煤热解自由基，抑制煤热解自由基的缩聚，提高煤热解过程焦油产率，为煤的清洁转化利用探索新途径。分别采用浸渍法和共沉淀法制备甲醇水蒸气重整催化剂，考察制备工艺及反应条件对其催化性能的影响，并通过分析表征，优化制备工艺，制得适合耦合过程的催化剂；对所选煤样进行热解特性及热解动力学研究，获得煤热解制油的最佳工艺参数范围；将甲醇水蒸气重整过程与煤热解过程结合起来，调整和优化工艺参数范围，使耦合过程协调进行，系统考察过程参数对焦油形成规律的影响；对耦合过程产物进行分析表征，建立耦合过程工艺参数与产物分布及组成之间的关系，并据此优化耦合过程工艺参数，使耦合过程朝有利于提高焦油产率和改善焦油品质的方向进行；利用稳定同位素示踪法对耦合过程机理进行探讨。

煤热解是一种重要的煤炭分质转化利用技术。现有热解工艺存在焦油收率低、焦油中重质组分含量高等问题。本项目将甲醇水蒸气重整过程与煤热解制油过程耦合，利用甲醇水蒸气重整过程中产生的大量活性中间产物和自由基稳定煤热解自由基，抑制煤热解自由基的缩聚，提高煤热解过程焦油产率，为煤的清洁转化利用探索新途径。分别采用浸渍法和共沉淀法制备了Ni基甲醇水蒸气重整催化剂，考察了制备工艺及反应条件对其催化性能的影响；研究了甲醇蒸气预处理对煤的物理化学性质及热解产物分布的影响；考察了工艺条件对甲醇蒸气气氛下煤热解过程的影响规律；将甲醇水蒸气重整与煤热解过程耦合，研究了4种不同的Ni基催化剂、热解过程工艺条件如温度、水醇比、流量等因素对耦合过程产物分布及组成的影响规律，获得了合适的工艺参数；对耦合过程机理进行了初步的分析探讨。研究结果表明，甲醇蒸气预处理改变了煤的化学组成，煤中的孔隙孔径增大，促进了热解焦油产率的增加；甲醇气氛能提高煤热解过程焦油收率并改善焦油品质，在热解温度为550 ℃，甲醇流量为300 mL/min时，焦油收率可达到14.9%；甲醇水蒸气重整与煤热解耦合过程能显著提高煤热解焦油产率，在热解温度550 ℃，水醇比1.2，水醇流量为300 mL/min时，耦合过程焦油产率可达到16.1 %，且在此条件下，焦油中轻质组分（苯类、酚类）的相对含量最高；焦油产率提高的原因是甲醇水蒸气重整过程中产生的大量活性中间产物和自由基与煤热解产生自由基相互作用的结果。项目研究工作为认识甲醇水蒸气重整与煤热解耦合过程中焦油的形成规律和机理，以及高焦油收率的煤热解工艺过程的实现提供重要的基础。