Study of small methanol conversion system for biomass resources

未利用的生物质资源和固体废弃物中的有机物转化为液体燃料后，可作为机动车的液体燃料。这种燃料的利用有利于减少化石燃料的消耗和全球变暖。在此背景下，进行了基础研究，以建立一个小型的热化学甲醇生产系统，使用生物质衍生的材料。本文首先从化学平衡出发，用热力学的方法研究了生物质热解过程中氢气和一氧化碳的生成过程。其次，使用流动反应器进行甲醇合成的动力学分析，其中在高压下供给模型气体，通过气相色谱分析产物。最后，提出了一种新型甲醇生产发动机。该发动机依靠往复式压缩机和往复式膨胀机的组合，所获得的结果总结如下：干生物质热解产生的气体需要加水来获得用于甲醇合成的气体混合物。固体碳的形成在热解过程中预测的各种气体混合物。对普通铜锌催化剂进行了甲烷合成的最佳条件的实验研究。甲醇产率在250℃时达到最大值，与反应器内压力无关，并随压力的增加而增加。在适当的停留时间下，产率可高达70%。分析表明，甲醇生产发动机的可能性，可以负担得起实现高压和能量回收。

Unused biomass resources and organic substance in solid wastes may be utilized as liquid fuels for motor vehicles once they are converted into liquid fuels. The utilization of such fuels favors reducing consumption of fossil fuels and global warming. With this background, fundamental studies were carried out to build a small thermo-chemical methanol production system that used biomass-derived materials. At first, pyrolysis of biomass and production of hydrogen and carbon monoxide were dealt with using thermodynamics based on chemical equilibrium. Second, kinetic analysis was made for methanol synthesis using a flow reactor in which model gases were fed at a high pressure, the products being analyzed by gas chromatograph. Last, a new methanol production engine was proposed. This engine relies on the combination of reciprocating compressors and reciprocating expanders.Obtained results are summarized as follows : Gas produced by pyrolysis of dry biomass requires water addition to obtain gas mixture for methanol synthesis. Solid-carbon formation during pyrolysis is predicted for a variety of the gas mixtures. Optimum conditions for methane synthesis are experimentally determined for the case of ordinary Cu-Zn catalyst. Yield of methanol reaches maximum at 250℃ irrespective of the pressure in the reactor and increases as the pressure increases. At a correct residence time, the yield may reach as high as 70%. Analysis shows the likelihood of the methanol production engine that may afford to achieve a high pressure and energy recovery.