Abstract Char structural changes occurring during gasification are normally only related to conversion and few data is published on the effect of carbon dioxide partial pressure on the extent of pore development. In this study, the char–CO2 reactivity and consequential pore development of different Highveld coal chars were investigated over a wide pressure range. Reactivity experiments were performed in a fixed bed reactor under reaction controlled conditions. The initial reaction rate was found to be solely a function of temperature and CO2 partial pressure and was well described by the Langmuir Hinshelwood rate equation. Surface analyses were performed on fresh and partially converted chars to quantify the effect of CO2 partial pressure on pore development. It was found that pores development more rapidly with conversion if the CO2 partial pressure is increased. This outcome has fundamental implications for the interpretations of gasification reaction kinetics. The term describing the total amount of active sites in the Langmuir Hinshelwood equation might not be constant at all partial pressures, and the possible impact of that is shown in this work. More work is required to further understand these effects and incorporate them appropriately into high pressure rate equations.

中文翻译：

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二氧化碳分压对高压下 Highveld 煤焦气化速率和孔隙发育的影响

摘要 气化过程中发生的焦炭结构变化通常仅与转化有关，关于二氧化碳分压对孔隙发育程度影响的数据很少发表。在这项研究中，研究了不同 Highveld 煤焦在很宽的压力范围内的炭-CO2 反应性和随之而来的孔隙发展。反应性实验在反应控制条件下在固定床反应器中进行。发现初始反应速率仅是温度和 CO2 分压的函数，并由 Langmuir Hinshelwood 速率方程很好地描述。对新鲜和部分转化的炭进行表面分析，以量化 CO2 分压对孔隙发育的影响。发现如果 CO2 分压增加，孔隙会随着转化而更快地发展。这一结果对气化反应动力学的解释具有根本意义。描述 Langmuir Hinshelwood 方程中活性位点总量的术语在所有分压下可能不是恒定的，这项工作显示了其可能的影响。需要做更多的工作来进一步了解这些影响并将它们适当地合并到高压速率方程中。