碳-水蒸气气化反应新机理探讨

The New Mechanism of Carbon-Steam Gasification Reaction

通过对碳-水蒸气气化反应特性分析,提出了全新的基于·OH自由基氧化性的碳-水蒸气气化反应机理,认为碳-水蒸气气化反应是各种复杂因素共同作用的结果,反应体系中·OH自由基的浓度是决定反应速率的关键因素;碳-水蒸气的气化反应速率取决于水的解离度,水的解离度大,产生·OH自由基增多,碳-水蒸气气化反应速率加快;催化剂对碳-水蒸气气化反应的催化作用也是因为碱金属能够降低水分子的解离活化能,有利于断键形成·OH自由基,从而降低了碳-水蒸气气化反应的初始温度,提高了碳-水蒸气气化反应的速率。碳-水蒸气气化反应的新机理的提出,能够合理描述碳-水蒸气气化反应过程,如何确立反应体系中·OH自由基的数目与气化反应速率的关联耦合机制将是今后研究的重点。

A new mechanism of the carbon-steam gasification reaction based on · OH radical oxidation was proposed through analysis on characteristics of the reaction. The reaction was considered as a result of the interaction of various complicated factors for the carbon-steam gasification reaction. The key factor deciding the reaction rate of the carbon-steam gasification was the concentration of · OH radicals in the reaction system. The reaction rate of the carbon-steam gasification depended on the degree of dissociation of water. The bigger the degree of dissociation of water was, the more· OH radicals were generated, and the faster the reaction rate of the carbon-steam gasification was. The function of the catalyst for the carbonsteam gasification reaction was realized by increasing the concentration of · OH radicals in the reaction system. The addition of alkali metal catalyst not only reduced the initial temperature of the carbon-steam gasification reaction, but also enhanced the reaction rate of the carbon-steam gasification. The main reason was that the alkali metal could reduce the dissociation activation energy of water molecules to form ·OH radicals. The carbon-steam gasification reaction process could be reasonably described by the proposed newmechanism of the carbon-steam gasification reaction. The associated coupling mechanism concerning the ·OH radical number and the gasification reaction rate will be the research focus in the future.