Reactive Capture of CO2 as Feestock for On-site Green Chemical Production with Absorbent Recycle

Although green hydrogen is the ultimate solution to eliminate CO2 emissions, the general consensus today is that green H2 is not economically competitive presently and in the near future. The conventional approaches are likely to dominate H2 and other fuel production in the intermediate term to at least 2030 to 2050 due to their advantage in technical maturity. Hence, decarbonization technology, such as CO2 capture from point sources of industrial manufacturing processes or combustion off-gas and its disposal, will be necessary to achieve GHG reduction targets in the near term. However, state-of-the-art carbon capture and storage (CCS) is not an ideal and convenient decarbonization solution for industrial point sources due to its economics, logistics and implementation. CO2 capture costs are dominated by the energy required for regeneration of spent absorbents and preparation of captured CO2 for sequestration. The actual capture step cost is insignificant. Hence, an economically sensible approach to decarbonization is to capture CO2 with a conventional scrubber as feedstock for downstream reutilization. Here, we propose the employment of an existing CO2 capture process to produce a feedstock for production of a green chemical, dimethyl carbonate (DMC). In the proposed process, the costly regeneration and compression step for CO2 capture can be eliminated. Dimethyl carbonate (DMC) is a promising green chemical due to its simplicity, versatility, low toxicity, high polarity, low corrosivity, and biodegradability. However, the market penetration of DMC is limited due to its currently high production cost, a result of the low reactor yields, and resultant high energy cost associated with product recovery and reactant recycle. Through the use of the reactively captured CO2 as feedstock and the integration of the molecular sieving inorganic membranes for product separation and recycle, the cost of DMC production is expected to be dramatically reduced. Thus, this proposed industrial decarbonization scheme is an economically driven approach and can be implemented in the near term.During the Phase I program we will be conducting bench scale testing of commercial and/or pilot demonstrated MPT membranes in the ultrafiltration, dehydration, and nanofiltration configurations to simulate the proposed process. Our existing ultrafiltration membrane will be demonstrated for the recovery of the chemically precipitated CO2 as feedstock for DMC production. Water and ammonia selective membranes will be used for DMC feedstock preparation and yield improvement. Finally, our organic stable nanofiltration membrane will be used for downstream product separation and recycle as an alternative to or integrated with downstream distillation in a hybrid system to overcome the energy intensive azeotropic distillation. With this data, a process model, LCA, and TEA will be updated. Utilization of CO2 captured from industrial point sources remains a significant challenge. DMC represents a significant opportunity to tap this “no cost” reactant, with a market potential of over $2 billion/year. Further, renewable chemicals will improve US security and stability by reducing dependence upon depleting fossil oil supplies from politically volatile regions.