1kW SOFC-CHP系统用催化燃烧耦合蒸汽重整反应器的实验研究

Experimental study on reactor integrating catalytic combustion and steam reforming for 1 kW SOFC-CHP

针对1 k W固体氧化物燃料电池热电联供（SOFC-CHP）系统开发了集成催化燃烧、换热及蒸汽重整的反应器,搭建了性能评价系统,系统研究了燃烧侧气体组分及工艺参数对该反应器性能的影响规律。实验结果表明：在反应器燃烧侧气体入口温度为300℃、空燃比为10：1、电堆燃料利用率为65%、水碳比为3的条件下,重整侧转化率达到73.6%,重整尾气中H2含量为67.5%。电堆燃料利用率对重整反应转化效率影响较大,其值大于80%时,采用尾气燃烧的余热回收方式无法有效为蒸汽重整提供所需热量。在150~350℃范围内,降低燃烧侧气体入口温度对重整反应效率影响较小,建议采用尾气先换热再进行催化燃烧的流程设计,保证重整效率的前提下可有效提升系统热效率。空燃比的降低可小幅度提升重整效率,在保证电堆反应温度稳定的前提下,适当降低空燃比可减少空气压缩机的功耗,从而提升整个系统的效率。研究成果对SOFC-CHP系统的优化和整体效率提升具有指导意义。

A reactor integrating catalytic combustion, heat exchange and steam reforming was developed for a 1 k W solid oxide fuel cell-combined heating and power system（SOFC-CHP）. Experiments were carried out to investigate the effect of combustion gas components and process parameters on properties of the reactor. The results showed that methane conversion rate was 73.6% and hydrogen concentration in the exhaust gas was 67.5% under operating conditions at the inlet temperature of combustion gas of 300℃, air-fuel ratio of 10：1, fuel utilization of stacks of 65% and water-carbon ratio of 3：1. Fuel utilization of the SOFC stacks had significant effect on methane conversion. Waste heat recovery from the exhaust gas combustion cannot provide enough heat for methane steam reforming when the fuel utilization was greater than 80%. Reduction of the inlet temperature of combustion gas had slight effect on methane conversion in the range of 150—350℃. Thus, it was recommended that the heat exchange can be firstly conducted before catalytic combustion to improve heat efficiency without obvious change to reforming reaction efficiency. Reduction of air-fuel ratio under the premise of ensuring the efficiency of reforming can decrease power consumption of the compressor and increase the system efficiency. This achievements can provide guidance to the increase of the whole system efficiency and optimum design of SOFC-CHP.