Natural gas reforming in thermochemical waste-heat recuperation systems: A review

Abstract

This article summarizes researches on thermochemical waste-heat recuperation (TCR) systems based on natural gas reforming. It includes the results of an industrial application, experimental lab tests, and simulation of TCR for various fuel-consuming equipment. A classification of thermochemical recuperation systems is proposed. In this review, thermochemical recuperation of different types of waste-heat such as exhaust gas, molten slag, elements of thermal protection has been considered. The TCR systems based on various reactions of methane reforming (with steam, carbon dioxide, a mixture of steam and carbon dioxide, steam and flue gases, a mixture of steam and oxygen) are summarized. After analyzing the articles on thermochemical recuperation, a flowchart of tasks for the TCR study was proposed. This flowchart can virtually be divided into six blocks: thermodynamic analysis; TCR configuration; heat and mass transfer in the reformer; catalysts design; synthesis gas combustion; experimental testing and industry application. The analyzed TCR systems perform the traditional function of ensuring waste-heat recovery and allow the production of fuel with superior characteristics containing molecular hydrogen. As a result, it becomes possible to use primary hydrocarbon fuel and hydrogen-rich gas – products of endothermic reforming. Considering, the global trend of using hydrogen as an energy source, the production of hydrogen at the equipment where it is consumed (on-board hydrogen production system) could use the TCR systems with endothermic hydrocarbon fuel reforming. According to this statement, analysis has been made on the impact of TCR on the emission of NOx and CO2, when synthesis gas after TCR systems is used. TCR based on steam methane reforming can be considered as ultralow NOx emission technology for gas turbine application.