Parameter optimization and performance evaluation of elliptical spiral mini-tube bundle reactor

Storage and transportation are one of the primary restrictions on the approach involving hydrogen energy. The traditional hydrogen storage methods, including high-pressure gas cylinder and cryogenic liquid tank show unfavorable economy, thus hindering their further industrial application and development. Metal hydrides can reversibly react with hydrogen and accomplish the hydriding/dehydriding process under mild operation conditions, which feature advantages such as large hydrogen storage amount, low operation pressure and energy consumption. This process is expected to replace the conventional hydrogen storage and transportation. Meanwhile, considering the strong endothermal/exothermic effect during hydrogenation/dehydrogenation, the prompt heat removal/support inside the metal hydride reactor is a key parameter for H₂ absorption/desorption rate and H₂ storage efficiency. To improve the heat transfer and absorption/desorption rates of metal hydride reactor, comprehensive analysis and evaluation were conducted. Based on the heat and mass transfer intensification, a new elliptical spiral mini-tube bundle reactor (ESMBR) with high efficiency was designed and proposed; the reactor possesses numerous features, such as high heat transfer speed, compact structure, high reaction rate, and convenient operation. All the hydrogen storage reactor models were established, and both the model accuracy and effectiveness were experimentally validated. Numerical simulations of ESMBR, spiral mini-tube bundle reactor, and mini-tube bundle reactor were calculated and compared by COMSOL. ESMBR was proven to exhibit favorable heat and mass transfer performance during the H₂ storage. Results of further analysis indicate that the sensitivity order of elliptical spiral structure parameters as follows: D_c > A > B > Pt > α. A multi-element valued model was used to evaluate the reactor schemes systematically, and the calculation results show the integrated superiority of ESMBR could achieve a value of 0.845. The comparison results indicate that the ESMBR presents an outstanding performance compared with other reactors and features a broad application prospect in the field of hydrogen energy.