Abstract:

The target of this study is to investigate the performance and efficiency of an integrated autothermal reforming and SOFC (solid oxide fuel cell) system fueled by methane. A zero dimensional SOFC stack model, which consists of electrochemical reactions and thermodynamics, is developed by Fortran and validated with experiment results, and links it to Aspen Plus software as a subroutine. Based on mass and energy balances, influences of steam to carbon(S/C) ratio and fuel utilization(U_f) on performance of SOFC power systems are investigated. The simulation results show that increase in the S/C ratio can enhance hydrogen production while reduce CO formation. Oxygen to carbon ratio and system efficiency achieve maximum when S/C ratio is 1.5. Increase of fuel utilization can enhance current density, resulting in increase of excess air ratio and decrease of air utilization. The overall efficiency and electric efficiency of the system all are increase because more chemical energy is converted into electric energy, whose maximum values are 44.5% and 39.2%, respectively. The performance characteristics obtained is of great significance for further optimization of integrated SOFC systems with autothermal reforming of natural gas.

Key words: solid oxide fuel cell, electrochemistry, methane, autothermal reforming, simulation, efficiency

摘要：

建立一个天然气自热重整的固体氧化物燃料电池(SOFC)系统模型,利用Aspen Plus化工流程模拟软件链接基于Fortran语言编写的电堆模型,在质量守恒和能量守恒的基础上,分析不同参数对系统性能的影响。模拟结果表明:随着水碳比的增加,甲烷和一氧化碳的转化率增大,导致氢气和二氧化碳含量增加;氧碳比和系统效率在水碳比为1.5时达到最大。随着燃料利用率的增加,电流密度增大,导致空气过量系数增大,空气利用率降低;系统的总效率和净效率均随之增大。尾气温度随着水碳比和燃料利用率的增加均呈现下降趋势。系统的最大总效率和净效率分别为44.5%和39.2%。研究结果为进一步优化自热重整系统指明了方向。

关键词: 固体氧化物燃料电池, 电化学, 甲烷, 自热重整, 模拟, 效率