(4av) Carbon Capture, Utilization and Storage: From Material Screeening to Process Optimization to Network Design

Atmospheric CO₂ levels, which surpassed 400 parts per million this year, are at their highest in human history. The continued increase in CO₂ levels is attributed to the anthropogenic CO₂ emissions from global consumption and burning of fossil fuels. The goal of my research is to design, optimize and screen processes, materials, and supply chain networks for cost-effective CO₂ capture, utilization and storage (CCUS) to reduce CO₂ emissions from stationary sources. This would enable the production of clean energy from carbonaceous fuels, and allow both conventional fuels (coal, oil and natural gas) and nonconventional fuels (shale gas, stranded natural gas, biomass, municipal solid waste, etc.) to continue to meet the global energy demands without emitting excess CO₂, thereby reducing the risks of global warming and man-made climate change.

In a CCUS chain, CO₂ is first captured and compressed at the source of emission, and then transported to a site where it can be utilized or injected for sequestration in geological formations. The costs of CO₂ capture and compression represent 60-70% of the total CCUS cost. Through process synthesis and optimization, we have explicitly shown how the investment and operating costs of absorption-, membrane- and adsorption-based post-combustion CO₂ capture processes would change from sector to sector, even from plant to plant, and how the carbon mitigation effort could benefit by early-adopting industries which have higher feed CO₂ compositions and flow rates [1–2].

More recently, we have demonstrated that no single materials-centric metric is adequate to identify the most cost-effective materials or processes for CO₂ capture, and we must combine atomistic, geometric and process understanding to screen materials and processes in tandem for CO₂ separation [3-4]. Using a hierarchical in silico screening method [3] that combines material screening with process optimization, we have identified many zeolites for cost-effective CO₂ capture from power plants for the first time. This has also unfolded the possibility to quickly explore the universe of microporous materials (zeolites and metal-organic frameworks) and membranes (polymeric and zeolitic) for discovery of novel applications that include, but are not limited to, carbon capture, natural gas upgrading, air separation, H₂ purification, and xylene separation.

It is also critical to integrate capture, compression, transportation, utilization and sequestration in an optimal fashion. To this end, we have designed a nationwide CCUS supply chain network [5] by considering simultaneous selection of materials and processes for CO₂ capture, selection of CO₂ sources, selection of utilization and sequestration sites, network costs, and actual geographic locations. Results suggest that it is possible to capture 50% of the current CO₂ emissions from the stationary sources in the United States at reasonable cost. Results for the CCUS in South Central United States and Texas are also favorable. Overall, it is found to be crucial to consider both the selection of materials and processes as integral parts of a large-scale CCUS network.

References:

[1.] Hasan, M. M. F.; Baliban, R. C.; Elia, J. A.; Floudas, C. A. Modeling, simulation, and optimization of post-combustion CO₂ capture for variable feed concentration and flow rate. 1. Chemical absorption and membrane processes. Ind. Eng. Chem. Res. 2012a, 51, 15642-15664.

[2.] Hasan, M. M. F.; Baliban, R. C.; Elia, J. A.; Floudas, C. A. Modeling, simulation, and optimization of post-combustion CO₂ capture for variable feed concentration and flow rate. 2. Pressure swing adsorption and vacuum swing adsorption processes. Ind. Eng. Chem. Res. 2012b, 51,15665-15682.

[3.] Floudas, C. A.; First, E. L.; Hasan, M. M. F.; Gounaris, C. E. Database screening method for cost-effective separations. U.S. Provisional Patent Application #61/761,436 and #61/765,284.

[4.] Hasan, M. M. F.; First, E. L.; Floudas, C. A. Cost-effective CO₂ capture based on in silico screening of zeolites and process optimization. Submitted for publication, 2013.

[5.] Hasan, M. M. F.; Boukouvala, F.; Floudas, C. A. Nationwide, regional and statewide CO₂ Capture, utilization and sequestration (CCUS) supply chain networks. Submitted for publication, 2013.