Analysis of the Heat Balance of a Metal Hydride Separator Used for the Separation of Hydrogen from Syngas

Abstract

The present article discusses the potential for hydrogen separation using a metal hydride separator, which facilitates the generation of hydrogen contained in syngas following the thermal recovery of wastes. The article provides a detailed description of the separator heat balance using analytical calculations and optimised calculations, and by applying numerical methods. The proposed concept of a separator intended for hydrogen separation from syngas offers a solution to a problem associated with the use of metal hydride alloy powders; in particular, their low thermal conductivity. In order to eliminate big temperature differences in the alloy, a heat transfer intensifier was implemented in the metal hydride alloy volume; the intensifier was made of metal and exhibited high thermal conductivity. For the purpose of comparing the thermal fields, the first stage comprised the creation of a numerical simulation of hydrogen absorption without the use of an intensifier. Subsequently, three different geometries were created for an intensifier intended to remove heat from the metal hydride alloy powder towards the separator cover, and the effects of these three geometries were analysed. The implementation of heat transfer intensifiers into the metal hydride alloy powder improved the heat removal by as much as 43.9% and increased the thermal field homogeneity by 77%. A result of the heat removal optimisation was an increase in the hydrogen absorption kinetics and the efficiency of the separator operation.