Design and performance study on the primary & secondary helical-tube reactor

Using metal hydride (MH) to store hydrogen is developing into an effective approach due to its high hydrogen storage capacity & prominent safety, and MH reactor can significantly advance hydriding & heat transfer rates consequently. In this work, a new primary & secondary helical-tube reactor (P&SHR) is proposed to simplify the reactor structure and improve hydriding rate and heat transfer efficiency, especially near the central H₂ tube and inner periphery region of the reactor. The results reveal that P&SHR owns an outstanding H₂ uptake performance, which takes less than 500 s to reach its saturated H₂ absorption capacity of 99%, saving 300-2700 s hydrogenation time compared with other reactors. Further sensitivity analysis indicates that the structural parameters of P&SHR follow the order: R_p > R′_p > P_t > P′_t > R′_s > R_s > R, whose optimal values are: 18 mm, 2.5 mm, 8 mm, 9 mm, 2.5 mm, 9 mm and 4 mm, respectively. Moreover, the operation parameters including H₂ supply pressure, initial temperature and heat transfer coefficient are systematically investigated, conforming that larger H₂ pressure and lower fluid temperature tend to promote the driving force and would be beneficial to hydrogenation process and future application scenario for P&SHR.