NEW Cu-Cl THERMOCHEMICAL CYCLE FOR HYDROGEN PRODUCTION WITH REDUCED EXCESS STEAM REQUIREMENTS

The Cu-Cl (copper-chlorine) thermochemical cycles for hydrogen production are leading examples of water-splitting methods. In this article, the heat requirements of different types of Cu-Cl cycles with various numbers of steps are analyzed, and their thermal design features are discussed in terms of water requirements, heat quantity, and heat grade. A challenge arises from the excess steam quantity requirement in the hydrolysis of CuCl(2). To address this challenge, a new type of Cu-Cl cycle is proposed in this article. It is found that the steam requirement can decrease by up to ten times, compared with conventional Cu-Cl cycles, and the heat grade of the hydrolysis step in the new cycle is significantly lowered from 375 degrees C to 150 degrees C. The engineering challenges of the new cycle are also discussed in the article.