Molten salt heat exchanger design for the thermolysis reactor in the Cu–Cl cycle of hydrogen production

The thermochemical copper–chlorine (Cu–Cl) cycle is known as a promising method for producing clean hydrogen. Due to the high-temperature environment of the thermolysis reactor, there are commercialization challenges with regard to the heat exchanger design. In this study, a new design for the heat exchanger used in the thermolysis reactor of a 4-step Cu–Cl cycle is presented, aiming to achieve the required temperature distribution of 430 °C–550 °C. A design methodology is developed for the heat exchanger along with an iterative algorithm for the sizing problem. The final design of this study has decreased the T* (representative of the temperature range) by 51 % compared to the previous designs, with the improvement techniques resulting in increasing the heat exchanger effectiveness and thermal performance factor by 15 % and 138 % and decreasing average TD (representative of the temperature dispersal) by 61 %. The achieved operating temperature ranges from 431.3 °C to 539.0 °C.