Title : Optimal design and sensitivity analysis of Gas-solid reactor for efficient H2 storage
Abstract:
Metal hydride (MH) has large hydrogen storage capacity and mild operation conditions, which is considered to be a promising method for H_2 utilization. Since the hydrogenation/dehydrogenation is reversible chemical reaction with strong thermal effect, the design and optimization of gas-solid reactor is crucial to H_2 storage and transportation. Based on the bionic optimization and constructal theory, a new bionic duplex DNA elliptical-tube reactor (B-D (DNA)-ER) is developed to descend the maximal axial temperature difference (?t) by 5.1 K/5.6 K for absorption/desorption inside the gas-solid reactor. The sensitivity analysis results of B-D (DNA)-ER indicate that the effect sequence of structural parameters (optimal value) on reaction rate should obey: major diameter (10 mm) > major axis (4 mm) > minor axis (2 mm) > pitch (6 mm) > installation angle (45°), which is consistent with the effect order of heat transfer tubes on the radial distribution in B-D (DNA)-ER. Therefore, the radial distribution of the heat transfer tubes was proved as the major factor to reaction performance compared to the axial direction. According to the theory of constructal entransy dissipation rate, a novel radiation mini-channel reactor (RMCR) is proposed to further improve the heat transfer and reaction performance through the arrangement of radial tubes. The calculation results illustrate that RMCR can significantly accelerate the H_2 absorption rate in radial direction, which may complete the hydriding process within 1200 s, causing the 11.4 K reduction of maximal radial ?t than B-D (DNA)-ER. The 7 reactors are extensively investigated and compared, revealing that the gas-solid reactor with radiation tubes own the best performance than others, which can save 77%, 52% and 37% reaction time than tank reactor, straight tube reactor and spiral tube reactor, respectively. The sensitivity analysis results indicated that axial pitch was the most sensitive structure factor for RMCR.
