Decarbonizing the Gas-to-Liquid (GTL) Process Using an Advanced Reforming of Methane Process
Zeinab Ataya, Mohamed S. Challiwala, Gasim Ibrahim, Hanif A. Choudhury, Mahmoud M. El‐Halwagi, Nimir O. Elbashir
Abstract
High Resolution Image Download MS PowerPoint Slide The gas-to-liquid (GTL) process is a promising technology for converting natural gas into synthetic fuels and chemicals. However, its high carbon dioxide (CO 2 ) emissions present significant challenges. Methane reforming contributes up to 60% of GTL’s CO 2 emissions, necessitating decarbonization. Dry reforming of methane (DRM) shows potential for CO 2 conversion. Still, it faces challenges such as high energy requirements, catalyst deactivation, and an incompatible hydrogen-to-carbon monoxide (H 2 /CO) ratio for GTL processing, requiring extensive research. A previous study proposed a two-reactor system known as CARGEN that co-produces solid carbon (in the form of multiwalled carbon nanotubes [MWCNTs]) and syngas, reducing CO 2 emissions by 40% compared to the benchmark autothermal reforming (ATR) process through life cycle assessment (LCA) studies. This paper presents a comprehensive simulation of the advanced DRM process used to retrofit an existing ATR-based GTL plant─initially, a 50,000 bbl./day ATR-based GTL plant is simulated. The advanced reformer process replaces ATR through retrofitting. Comparative analysis shows a remarkable 73% reduction in net CO 2 emissions and the potential coproduction of 243 kg of MWCNTs per barrel of syncrude, equivalent to 12,150 tons/day of MWCNTs. However, the advanced reformer-based GTL plant requires 61% more natural gas feedstock while utilizing 79% less oxygen than the ATR-based plant. Furthermore, a separate techno-economic analysis examines the advanced reformer-based GTL plant based on a calculation for 13,100 tons/day of CO 2 feedstock to co-produce 3,277 tons/day of MWCNTs and 50,000 barrels/day of syncrude. This analysis, considering a 25% tax rate, 25-year plant life, and zero salvage value, demonstrates an attractive 10-year payback period at selling prices of 80 USD/bbl. for syncrude and 10 USD/kg for MWCNTs. These results provide a process system-level perspective, showcasing the advanced reformer-based GTL plant (CARGEN Process) as an effective solution for low-carbon GTL production.