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: Rp > R′p > Pt > P′t > R′s > Rs > 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.