Hydrogenation and Liquefaction of Waste Plastics through Partical Oxidation and Water Gas Shift Reaction in Supercritical Water

研制了废塑料在超临界水中部分氧化和水煤气移位反应加氢工艺。在本研究中，为了开发该工艺，我们对关键反应进行了基础研究，即1)烃类热解，2)烃类部分氧化，3)超临界水中部分氧化和水煤气移位（WGS）反应加氢。结果如下：1)烃-超临界水体系相平衡的测量我们研制了一种新型设备（高温高压振动密度测定仪）来测量烃-超临界水体系的相平衡。2)烃类在超临界水中热解，采用间歇式反应器对聚乙烯进行热解实验。结果表明：随着水密度的增加，l-烷烃/烯烃比增大，产物分布向短链烃转移；这一结果可以通过考虑反应相随水密度的变化来解释。3)超临界水中烃类部分氧化加氢的研究。采用间歇式反应器进行了正十六烷在超临界水中部分氧化的实验。结果表明，随着水密度的增加，CO和正构烷烃生成的选择性增强。正构烷烃选择性的提高说明生成的CO与水反应生成H2，然后l-烷烃加氢生成正构烷烃。我们还利用流动装置进行了超临界水中CH4部分氧化的实验。CO的选择性随水密度的增加而增加。我们采用了常见于CH4气相氧化的自由基网络模型来描述超临界水中CH4的部分氧化。考虑水密度效应，对生成H2O2的基本反应进行修正，可以用模型描述超临界水中CH4部分氧化的反应速率和产物分布。在上述实验结果的基础上，对烃类部分氧化连续工艺进行了可行性研究。结果表明：a)烃类原料浓度应高于10%，b)氧气浓度应在15%左右，c)以液相供氧为宜。上述结果表明，超临界水中部分氧化催化加氢和水煤气移位反应具有较高的碳氢化合物加氢潜力。少

We have developed a hydrogenation process of waste plastics through partial oxidation and water gas shift reaction in supercritical water. In this research, for the development of the process, we conducted the basic study of the key reactions, namely 1) pyrolysis of hydrocarbon, 2) partial oxidation of hydrocarbon, and 3) hydrogenation through partial oxidation and water gas shift (WGS) reaction in supercritical water. The results are as follows.1) Measurement of phase equilibria of hydrocarbon - supercritical water systemWe have developed the new equipment (vibrational density measurement apparatus for high temperature and pressure) to measure the phase equilibria of hydrocarbon - supercritical water system.2) Pyrolysis of hydrocarbon in supercritical waterPolyethylene pyrolysis experiments were conducted by using batch reactors. The results showed that l-alkane/alkene ratio increased and product distribution shifted toward shorter chain hydrocarbons with increasing water density. Thi … More s result can be explained by considering change of the reaction phase with water density.3) Study on hydrogenation of hydrocarbons through partial oxidation in supercritical water.The experiments of partial oxidation of n-hexadecane in supercritical water were conducted by batch reactors. In the results, the selectivities of CO and n-alkane formation were enhanced with increasing water density. The increase in n-alkane selectivity indicates that the produced CO reacted with water to produce H2 followed by the hydrogenation of l-alkane to n-alkane.We also conducted the experiments of partial oxidation of CH4 in supercritical water using a flow apparatus. The selectivity of CO increased with increasing water density. We applied a radical network model, which is commonly used for the gas-phase oxidation of CH4, for describing the partial oxidation of CH4 in supercritical water. Modifying the elementary reactions of forming H2O2 with considering the water density effect, we could described the reaction rate and the product distribution of the partial oxidation of CH4 in supercritical water by model.4) Designs of a continuous processWe made a feasibility study for a continuous process of partial oxidation of hydrocarbon based on the above experimental results. The results suggest that a) the feed concentration of hydrocarbon should be higher than 10%, b) oxygen concentration should be around 15%, and c) liquid phase feeding of oxygen is preferable.The above results suggest that catalytic hydrogenation through partial oxidation and water gas shift reaction in supercritical water have a high potential for hydrogenation of hydrocarbons. Less