Thermal Ammonia Decomposition for Hydrogen‐Rich Fuel Production and the Role of Waste Heat Recovery

Abstract

Hydrogen is an attractive future fuel with the potential to play a crucial role in reducing carbon dioxide emissions, but the major obstacles to implement hydrogen are associated with its storage, transportation, and safety. As a solution, ammonia has been recognized as a promising carbon‐free hydrogen carrier; however, due to the poor combustion performance of ammonia fuel, this review first outlines the significance of on‐site ammonia decomposition to generate COx‐free H2‐rich fuel. Furthermore, to demonstrate the potential of this approach in different fields, the main focus of this review is on the pivotal role of integrating waste heat recovery and thermal ammonia decomposition across various industries including power plants, transportation, and industrial furnaces, enabling researchers to gain insights and benefit from the work of each other. As a means to enhance fuel saving and reduce greenhouse gas emissions, two significant methods including thermochemical recuperation and autothermal reforming are investigated considering the impact of several factors like exhaust gas species, temperature, and the performance parameters of the main fuel consumers. Finally, the paper provides vital recommendations for research directions in waste heat recovery‐based ammonia decomposition systems to promote sustainable and eco‐friendly solutions applicable to various industries. These include but are not limited to conducting life cycle analyses considering green ammonia, optimization of the independency level for the decomposition system, and integrating it with various components such as dual‐fuel engines, hydrogen purification, solar energy, and fuel cells.