燃料预重整份额对SOFC-GT混合发电系统设计的影响

Effects of Fuel Pre-reforming Ratio on System Design Performance of a Natural Gas Solid Oxide Fuel Cell/Gas Turbine Hybrid System

针对以天然气为燃料的固体氧化物燃料电池(solid oxide fuel cell,SOFC)-燃气轮机(gas turbine,GT)混合发电系统,利用平衡态重整器模型、一维SOFC模型以及搭建于Ebsilon^(■)中的燃气轮机系统模型,在不同燃料预重整份额和SOFC燃料利用率的设计工况下,开展混合发电系统的性能分析研究。结果表明,高SOFC燃料利用率并不会对应高的系统发电效率。混合发电系统效率最高点出现在热耦合策略对系统性能影响最小的设计工况下。燃料内重整可以提高混合系统的效率,但也要求SOFC运行在极端的设计工况下;燃料外重整则可以提高系统设计的灵活性,降低混合发电系统对SOFC的依赖。仿真分析显示,通过合理配置SOFC燃料利用率和燃料重整过程,有望在不依赖燃料内重整的情况下,提高混合发电系统的发电效率。

A design study was undertaken of a 100kW natural gas solid oxide fuel cell(SOFC)/gas turbine(GT)hybrid system to evaluate the impacts of reforming process under a broad range of SOFC fuel utilizations.An equilibrium reformer model and a one-dimensional SOFC model were employed to perform system study for this hybrid,while balance of plant model was built in Ebsilon^(■)to simulate the associated performance of gas turbine cycle.Fifty design cases with varied external fuel reforming temperatures were analyzed based on different SOFC fuel utilization levels.Results show that high SOFC fuel utilization was not related to high efficiency in SOFC/GT hybrids.Optimal design cases in terms of efficiency occurred at the design conditions where the penalty of thermal management was minimized.Internal reforming could improve the system efficiency but it require SOFC operating at extreme design conditions;while external reforming provided a higher design flexibility and showed opportunities of efficiency improvement with thermal integration.