Abstract:

Ammonia cracking for hydrogen production is an emerging method that utilizes the exhaust gas from ammonia combustion as the heat source. A multi-physics coupling numerical model of an ammonia cracking reactor utilizing the waste heat from ammonia-hydrogen combustion was established. In this model, the catalytic region was treated as a porous media. The effects of exhaust gas and ammonia inlet temperature, velocity and flow patterns on ammonia conversion, hydrogen yield, and thermal efficiency were investigated. The results showed that increasing the exhaust gas inlet velocity and temperature, increasing the reactant inlet temperature, and decreasing the reactant inlet velocity could significantly improve the ammonia conversion and hydrogen yield. Additionally, increasing the exhaust gas inlet temperature and reactant inlet velocity, decreasing the exhaust gas inlet velocity and the reactant inlet temperature could be helpful to improve the thermal efficiency of the reactor. Notably, the exhaust gas parameters had a greater influence on thermal efficiency compared to the reactants. These findings contributed to the design and optimization of ammonia cracking reactors integrated with the waste heat from ammonia-hydrogen combustion utilization.

Key words: ammonia cracking, hydrogen production, packed bed, porous media, exhaust heat utilization

摘要：

氨裂解制氢是一种新兴的制氢方式，采用氨氢燃烧的余热烟气为热源。本文建立了以氨氢燃烧余热为热源的氨裂解反应器多物理场耦合数值模型，将催化区域视为多孔介质模型，研究了余热烟气和反应物氨的进口温度、流量以及流型等对氨转化率、产氢率、热利用率等反应器性能的影响。结果表明，提高余热烟气进口流量和温度、提高反应物进口温度以及降低反应物进口流量可明显提高氨制氢的转化率；提高余热烟气进口温度和反应物进口流量，降低余热烟气进口流量和反应物进口温度对提升反应器整体热利用率有帮助，余热烟气因素对热利用率的影响大于反应物。研究结果有助于耦合氨氢燃烧余热烟气利用的氨裂解反应器的设计和优化。

关键词: 氨裂解, 制氢, 填充床, 多孔介质, 余热利用