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为了提高SOFC联供系统的综合利用效率和降低CO_2捕集能耗,提出一种基于SOFC循环的CO_2近零排放冷热电联供系统。建立了系统数学模型,给出了设计工况下各点的热力参数值,分析了燃料利用率、空燃比、燃料电池入口温度与工作压力变化对系统性能的影响。结果显示,在设计工况下,SOFC发电效率、联供系统净发电效率和一次能源利用率分别为51.59%、53.84%和72.01%,与没有CO_2捕集的联供系统相比,净发电量降低了3.66%,一次能源利用率降低了2.05%。变参数研究结果显示,随着工作压力的增加,SOFC的发电效率增大,而系统净发电效率和一次能源利用率减小;另外,增加空燃比会降低SOFC发电效率、系统净发电效率和一次能源利用率,所以在保证SOFC在正常工作情况下应选择较小的空燃比。在燃料利用率和阴极入口温度变化中,SOFC的输出功率和输出电压先增加后减少,而阳极入口温度变化对SOFC性能影响较小。
In order to improve the comprehensive utilization efficiency of SOFC combined system and reduce the energy consumption of CO 2 capture, a CO 2 near-zero emission cogeneration system based on SOFC cycle is proposed. The mathematical model of the system was set up, and the parameters of the thermal parameters were given. The influence of fuel efficiency, air-fuel ratio, fuel cell inlet temperature and working pressure on system performance was analyzed. The results show that under the design conditions, the SOFC power generation efficiency, the net generation efficiency of the cogeneration system and the primary energy utilization rate are 51.59%, 53.84% and 72.01% respectively. Compared with the cogeneration system without CO_2 capture, the net generation capacity 3.66% lower, primary energy utilization decreased by 2.05%. The results of variable parameters show that with the increase of working pressure, the power generation efficiency of SOFC increases, while the net power generation efficiency and the primary energy utilization rate of the system decrease. In addition, increasing the air-fuel ratio will reduce the SOFC power generation efficiency, Energy efficiency, so to ensure that SOFC should be in the normal working conditions should choose a smaller air-fuel ratio. In the fuel utilization and cathode inlet temperature changes, the output power and output voltage of SOFC first increase and then decrease, while the change of anode inlet temperature has little effect on SOFC performance.