Numerical investigation of hydrogen charging performance for a combination reactor with embedded metal hydride and coolant tubes

Abstract

A two-dimensional model investigating the hydrogen charging process in a combination reactor filled with both LaNi 4.3 Al 0.4 Mn 0.3 and 2LiNH 2 -1.1MgH 2 -0.1LiBH 4 -3wt.%ZrCoH 3 materials has been developed. The selected configuration is a cylindrical reactor of 32 cm of diameter where the MeH is filled in annular tubes separated from the complex hydride bed by a gas permeable layer. The diffusion of hydrogen towards the two storage media is ensured by filters embedded in the middle of the MeH tubes whereas the coolant tubes are placed in the centre of their triangular arrangement. Simulation results have shown that the charging process depends on the MeH reaction heat required for the initiation of the CxH reaction as well as the heat management once the complex hydride starts to store hydrogen. High hydrogen storage rates and short refueling times can be obtained by increasing the number of MeH and coolant tubes and ensuring an efficient heat removal at the peripheral area of the CxH media. A refueling time of 3 min is achieved for an optimum configuration of 49 MeH tubes and 96 coolant tubes while increasing the thermal conductivity of the CxH media to 3.5 W/(m K). Such a result could make the identified optimum configuration as a suitable hydrogen storage system for fuel cell forklift trucks since it meets the requirements of this application in terms of weight and size.

Review of thermal management technology for metal hydride reaction beds

“…Not only does this collection enhance the hydrogen storage capacity, but it also enlarges the region where the MHB comes into contact with the coolant. [32][33][34][35][36][37] As shown in Fig. 2b, 33 nine tubular MHRs are located inside with the coolant added outside the tubes, in which nearly 90% improvement in storage time can be achieved by optimizing the parameters.…”

SSH2S: Hydrogen storage in complex hydrides for an auxiliary power unit based on high temperature proton exchange membrane fuel cells

“…Moreover, the best CxH:MeH gravimetric ratio for optimizing the kinetics of absorption and desorption has been calculated to be equal to 1:1. The complete results of finite elements simulations were published To be submitted to Journal of Power Sources elsewhere [32][33][34]. On the basis of that complete study, the geometry of the single storage vessel was defined: each container is built using stainless steel and comprises two concentric cylindrical compartments containing the MeH (inner shell) and the CxH (outer shell), as shown in Figure 4a.…”

Machine learning modelling and optimization for metal hydride hydrogen storage systems

“…water). [22][23][24][25] The embedded HTF tubes and HTF concentric jacket heat exchanger arrangements within the MH bed primarily result in a higher overall heat transfer coefficient due to uid ow within them along with additional…”

“…water). 22–25 The embedded HTF tubes and HTF concentric jacket heat exchanger arrangements within the MH bed primarily result in a higher overall heat transfer coefficient due to fluid flow within them along with additional heat transfer surface area. 26–29 In recent times, incorporation of heat pipes and nanofluids to enhance the MH system performance has been studied as heat exchange solutions.…”