The Demonstration of the Superiority of the Dual Ni-Based Catalytic System for the Adjustment of the H2/CO Ratio in Syngas for Green Fuel Technologies

Abstract

A novel dual Ni-based catalytic process (DCP) to control the H2/CO ratio of 2 in the syngas product within one step at temperature <700 °C was created and constructed. With the sequence of the catalysts located in the single reactor, the endothermic combined steam and CO2 reforming of methane (CSCRM) reaction and the exothermic ultra-high-temperature water–gas shift (UHT-WGS) reaction work continuously. During the process, the H2/CO ratio is raised suddenly at UHT-WGS after the syngas is produced from CSCRM, and CSCRM utilizes the heat released from UHT-WGS. Due to these features, DCP is more compact, enhances energy efficiency, and thus decreases the capital cost compared to reformers connecting with shift reactors. To prove this propose, the DCP tests were done in a fixed-bed reactor under various conditions (temperature = 500, 550, and 600 °C; the feed mixture (CH4, CO2, H2O, and N2) with H2O/(CH4 + CO2) ratio = 0.33, 0.53, and 0.67). According to the highest CH4 conversion (around 65%) with carbon tolerance, the recommended conditions for producing syngas with the H2/CO ratio of 2 as a feedstock of Fischer–Tropsch synthesis include the temperature of 600 °C and the H2O/(CH4 + CO2) ratio of 0.53.