Investigation of Hydrogen and Methane Production from Flue Gas Released from the Steel Industry

Abstract

This paper concerns a potential multigeneration system where the flue gas is generated to be utilized for power, hydrogen and methane production, and an additional subsystem where the blending of 20% hydrogen into the methane is accomplished for residential usages. The proposed system mainly involves combined Brayton and organic Rankine cycles, water-gas shift reactor, Sabatier reactor, and combustion chamber. The Aspen Plus simulations are performed for the development and assessment of the presented multigeneration system. When the flue gas temperature is 815 degrees C, the work rate generated is 41.6 MW. As another beneficial output, the Sabatier reactor's CH4 production rate is 0.26 kg/s, and a part of it is sent to blend with hydrogen at amolar fraction of 0.20 in the blend for household applications. It is observed that when combustion temperature of the blend increases from 800 degrees C to 1200 degrees C, the CO2 emissions decrease from 2.63 kmol/h to 1.42 kmol/h, and the net released heat from the combustion reactor decreases from 1175 kW to 944 kW. Furthermore, the overall energetic and exergetic efficiencies of the system are calculated as 52.1% and 68.9%, respectively.