气化参数影响气流床煤气化的模型研究(Ⅱ)——模型预测及分析

Modelling on effects of operation parameters on entrained flow coal gasification (Ⅱ): Model prediction and analysis

为评价和优化气流床煤气化中的气化方案和气化参数,利用已建立的气流床煤气化动力学模型系统地研究了不同气化剂、气化剂质量比率、气化温度、气化压力和停留时间等参数对气化过程和煤气组分的影响,并对其影响机理及规律进行了分析.结果表明:O2/H2O和O2/CO2两种气化方案各有特点,O2/H2O气化剂方案反应速度快,煤气中H2体积分数高,而O2/CO2气化剂方案可以降低未分解的水煤气,并回收利用CO2.气化温度是影响气化进程和煤气组分的最关键因素,气化压力对气化反应进程影响较大,但对接近平衡时的煤气组分影响却较小;对给定的气化反应系统,存在最佳气化剂质量比率和停留时间.

Calculations were carried out to determine the effects of gasification parameters on the performance of entrained flow coal gasification using the mathematical model previously established by the authors. The studied gasification parameters included gasifier species and its ratio to gasifying medium, gasification temperature, gasification pressure and residence time. Main results obtained are as follows: Using O_2/H_2O and O_2/CO_2 as gasifying medium separately have their own advantages; The gasification reaction rate is fast and the production rate of H_2 is increased with O_2/H_2O as gasification medium while the un-reacted steam is reduced and CO_2 is recovered with O_2/CO_2 as gasification medium. Gasification temperature is a key factor on the gasification process and syngas composition, while gasification pressure has significant influence on gasification process but a little on syngas composition near equilibrium. There are optimal mass ratio of gasifier to gasifying medium and residence time for a given gasification system.