煤与甲烷共转化制合成气过程的热力学分析

A thermodynamic analysis of combined coal gasification and methane reforming for synthesis gas production

  • 摘要: 采用Gibbs自由能最小法,对流化床煤与甲烷共转化过程进行了热力学分析。在保持体系绝热温度为常压流化床煤气化的操作温度1273K下,将煤与甲烷共转化过程的冷煤气效率、产出合成气的单位有效能氧耗及H2/CO比等指标与单纯煤气化过程进行了比较。结果表明,在煤气化体系中增加甲烷进料,能使冷煤气效率提高,单位有效能氧耗降低,产出合成气的H2/CO比可调。此外,甲烷可作为部分氢源,降低过程水耗。从热力学角度证明了煤与甲烷共转化方法对于有效利用煤层气的优越性,所得出的操作线也为该过程的实际操作指出了方向。

     

    Abstract: A detailed thermodynamic analysis of the combined coal gasification and coal-bed methane reforming under conditions prevailing those in fluidised-beds has been performed using the Gibbs free energy minimization method. By keeping the adiabatic temperature of the reaction system to 1273K, coal gasification alone is compared with the combined coal gasification and methane reforming in terms of cold gas efficiency, oxygen consumption and product gas H2/CO ratio. The results show that increasing methane feed in the gasification system can improve the cold gas efficiency and reduce the oxygen consumption. The H2/CO ratio of the synthesis gas produced is adjustable. Methane is shown to play in part the role of steam and thus reduce the water consumption in the combined process. The findings of the present analysis testify the advantage of combined coal gasification and coal-bed methane reforming process as an alternative means of coal-bed methane utilisation and provide useful guidelines for potential practical applications.

     

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