Integrated Carbon Capture and Conversion To Produce Syngas: Novel Process Design, Intensification, and Optimization

An integrated, modular, and multifunctional process is conceptually designed, simulated, and optimized for direct utilization of CO 2 from dilute flue gas to produce high-quality syngas, a precursor for many value-added chemicals and liquid transportation fuels. The process is intensified to simultaneously capture and convert CO 2 using methane, natural gas, or excess fuel gas from the same plant, or using nearby unconventional methane from biogas or landfill gas. It is an integrated adsorption-purge-reaction system where CO 2 is first adsorbed and then desorbed using methane-rich feed leading to a mixture suitable for dry-reforming. The merging of concentration-based CO 2 desorption with the reactor feed premixing step eliminates the need for pressure or temperature swings and significantly reduces the energy penalty and cost of CO 2 capture and utilization. The process is simulated at different conditions using a high-fidelity process model to elucidate the effects of key decision variables as well as the trade-offs and interactions between the capture and reforming sections. The technology is flexible to handle different feedstock compositions, and is amenable to both centralized and distributed production of syngas. A constrained grey-box optimization method is employed to achieve a maximum of 99.7% net overall CO 2 utilization considering auxiliary emissions at a total cost ranging from $110–130 per ton of syngas. As much as 14.6% of the total CO 2 input to the process comes “directly” from flue gas without additional cost for CO 2 capture while maintaining about 91% overall CO 2 utilization. The technology is also computationally found to be robust in terms of CO 2 utilization and cost for different natural gas feeds with CO 2 contamination as high as 60%. This can be attributed to the novel process intensification concept and the gray-box constrained optimization method presented in this work.