煤气化过程的动态建模和负荷响应特性分析

Dynamic modeling of the gasification process and analysis of load response characteristics

中文关键词: Shell气化炉  渣层物性  负荷响应  惯性时间常数

英文关键词: Shell gasifier  slag layer physical properties  load response  inertial time constant

中文摘要:

      针对限制整体气化联合循环发电系统的关键单元，本文建立了合成气生产过程仿真模型，针对不同负荷过程，模拟了系统动态变化过程，分析了不同煤渣特性对应的炉膛内参数的动态行为，获得了负荷响应过程中合成气参数变化规律和炉内惯性的大小。结果表明液态比热容直接影响固液之间的传质，造成排渣量的大幅上升，导致炉内储热能力下降，温度升高。熔融温度越高，平衡时间越长，系统惯性越大。固态渣层比热容增大，排渣量降低，但不影响最终厚度。氧煤比是影响合成气生产过程负荷响应的关键参数，负荷升高，氧煤比的降低导致出口温度下降，渣层厚度提高，进一步增大了炉内热阻，水冷壁壁面温度显著降低。对于炉内参数的负荷响应特点，结果表明了渣层厚度的响应时间远高于温度和成分。而对于不同的物流输入信号，响应曲线的总体变化趋势一致，但考虑输入物流的延迟性后，参数响应曲线斜率下降，同时引起响应曲线的波动。

英文摘要:

      In this study, a simulation model of the syngas production process was developed to analyze the dynamic behavior of key units within the gasification combined cycle power system under varying load conditions. The research focused on the dynamic variation of furnace parameters in response to different coal ash char-acteristics. Additionally, the variation patterns of syngas parameters and furnace inertia during load re-sponse were examined. The results show that the liquid specific heat plays a crucial role in mass transfer between solid and liquid phases, resulting in a significant increase in slag removal and a decrease in ther-mal storage capacity within the furnace, thereby leading to higher temperatures. That higher melting tem-peratures prolong equilibrium time and increase system inertia. Moreover, an increase in the specific heat of the solid slag layer reduces the amount of slag removal but does not impact the final thickness of the slag layer. The results identify the oxygen-to-coal ratio as a key parameter affecting load response in the syngas production process. As the load increases, a decrease in the oxygen-to-coal ratio leads to a decrease in outlet temperature, an increase in slag layer thickness, and enhanced thermal resistance within the fur-nace, resulting in a significant decrease in water-cooled wall temperature. Furthermore, the response time of the slag layer thickness is considerably longer than that of temperature and composition during load response. When examining different input signals of material flow, the overall trends in the response curve are the consistently same. However, accounting for the delay of input material flow decreases the slope of the parameter response curve and introduces fluctuations in the response curve.