Techno-economic assessment of flare gas valorisation during membrane-based GTL process by net-zero strategy

This study focuses on the techno-economic comparison of flare gas from an industrial stream valorisation into liquid fuels, comparing conventional gas-to-liquid (GTL) and membrane-based processes. Both processes encompass flare gas sweetening, synthesis gas production, and FT synthesis units. Integration of membrane-based GTL could decrease the overall liquid fuel production by 1.5%, with power requirements 47.3% higher and lower overall energy and steam demand of 25.8% and 21% respectively. The initial analysis indicates a 23.3% decrease in total carbon emissions for the Membrane-based GTL process compared to the Conventional GTL process. The Membrane-based GTL process demonstrates a potential 13% reduction in total capital investment and an 11.8% decrease in production cost for liquid fuel products, coupled with a remarkable 22.5% higher return on investment. Moreover, the payback period in the membrane-based GTL process is reduced by approximately 20.9%. In the membrane-based gas sweetening unit, the total capital investment and production costs increase by approximately 5%. In comparison, the membrane-based process for the FT unit offers a cost-saving approach of around 10.4%. Hence, the incorporation of membranes throughout the process will yield substantial profitability. Upon conducting an in-depth analysis of the flare gas sweetening unit, it becomes evident that enhancing permeability by over 200% could potentially reduce the production cost of the sweetening unit. Consequently, this renders it more preferable and lucrative than the amine process.