Assessing the potential of CO2 utilization with an integrated framework for producing power and chemicals

The conventional thinking on CO2 utilization begins with the capture and concentration of CO2 from an emitting source. Here we propose the concept of a CO2-neutral chemicals production process comprising a network of reactions, which begin with the oxy-combustion of methane, the energy source for the process, and end with the production of chemicals with significant global demands. The proposed framework derives all its energy demand from methane and converts excess energy to electricity, and CO2 produced is converted to useful chemicals. The proposed concept provides a framework to obtain an optimistic estimate for the global impact of CO2 utilization subject to the maximum current and projected global demands for all chosen chemicals. Crucially, hydrogen produced internally in the process is not sufficient to achieve both CO2 neutrality and meet global demands for the chosen chemicals. Thus, based on the source of hydrogen, we present results from three different scenarios. First, we assumed unlimited renewable hydrogen supply. In this scenario, the estimated CO2 avoidance was 59% for the 2013 emission levels. The CO2 avoidance dropped dramatically to 6% in the second scenario, which assumed renewable energy at its current global levels. Finally, if the process were limited by the internally produced hydrogen only, then the CO2 avoidance reduced to 1%. Thus, the potential of CO2 utilization depends on the availability of renewable hydrogen. (C) 2017 Elsevier Ltd. All rights reserved.