V.N. Daggupati

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 CuCl2. 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°C to 150°C. The engineering challenges of the new cycle are also discussed in the article.