Integrated Optimization of Flare Gas for Hydrogen Production, Power Generation, and Emission Control

Abstract This study presents a multi-objective optimization (MOO) of a flare gas-fuelled Solid Oxide Fuel Cell (SOFC) system. Three conflicting objectives, such as hydrogen flow rate maximization, fuel utilization maximization, and global warming potential (GWP) minimization, were considered. The Pareto-optimal solutions in four important decision variables, i.e., stack inlet air pressure, fuel feed flow, stack operating temperature, and steam/carbon ratio, have been obtained through the Non-dominated Sorting Genetic Algorithm (NSGA-II). It was found that the optimal performance is achieved at the stack temperature of 1150–1200 K, air pressure of 1.6–2.0 atm, and steam-to-carbon ratio of 2–3. Notably, a moderate hydrogen production rate of 0-1.5 kmol/hr was associated with significantly lower GWP values. Though hydrogen production was increased with the rise in fuel flow rate, the excess input lowers efficiency and increases emissions. The results illustrate the successful trade-off approach for power and hydrogen generation and show a promising pathway to low-emission energy systems for flare from the oil and gas industry.