(80f) A Framework for the Combined Evaluation of Economic and CO2 Fixation Feasibility of Carbon Capture and Utilization (CCU) Reaction Pathways

A global effort is underway to reduce GHG emissions to address the growing concerns of anthropogenic climate change. At 8.5 Gt_CO2 in 2020, industrial greenhouse gas (GHG) emissions account for approximately 24% of total global anthropogenic emissions. Therefore, the industrial sector needs to reduce GHG emissions by 1.2% to 7.4 Gt_CO2 by 2030 to meet sustainability and decarbonization targets. Carbon dioxide capture and utilization (CCU) has garnered significant attention as a means of reducing GHG emissions and for decarbonizing several industries, including the natural gas industry, the cement industry, and the steel manufacturing industry. One means of applying CCU to a process is through the chemical conversion of CO_{2 ­­}into other products. Not all CCU processes may be economically feasible or environmentally sustainable in terms of CO2 fixation. Typically, to assess the CO2 fixation of a given CCU reaction, a life cycle assessment (LCA) is conducted. Additionally, a technoeconomic assessment (TEA) is carried out to evaluate the economic viability of the process. It should be noted that conducting these assessments requires significant effort and time, as well as a substantial amount of theoretical and empirical data. Therefore, it is recommended to perform these assessments at a later stage in the development and scale-up of a CCU technology.

In this work we develop a framework for the combined evaluation of economic and CO₂ fixation feasibility of CCU reaction pathways at early stages of the technology’s development by integrating two metrics: the metric for inspecting sales and reactants (MISR) and the CO2Fix. The MISR is a metric used to assess the economic feasibility of any commercial reaction. The CO2Fix estimates the CO₂ fixation capacity for a given CCU reaction, accounting for Scope 1 and Scope 2 emissions, while providing an upper limit for CO₂ fixation. Both metrics use limited information obtained from the reaction stoichiometry and basic thermodynamic properties of the materials involved in the reaction. The framework categorizes a given CCU conversion technology into one of 4 types: Type 1 technologies that are both economically feasible (MISR>1) and lead to CO₂ fixation (CO2Fix>1), Type 2 technologies that lead to CO₂ fixation (CO2Fix>1) but are not economically feasible on their own (MISR<1), Type 3 technologies that are economically feasible (MISR>1) but do not lead to CO₂ fixation on their own (CO2Fix<1), and Type 4 technologies that are neither economically feasible (MISR<1) nor lead to CO₂ fixation (CO2Fix<1). Furthermore, the framework enables the estimation of various parameters necessary to determine the economic and CO₂ fixation viability of different CCU technologies. Specifically, (a) it allows for the estimation of the minimum subsidy required for a Type 2 CCU conversion technology to become economically feasible, (b) the minimum amount of CO₂ capture necessary for a Type 3 technology to become a CO₂ fixing technology, (c) the minimum CO₂ credit required for a Type 2 technology to become economically feasible, (d) and the maximum CO₂ capture cost required for a Type 3 technology to become CO₂ fixing while maintaining economic feasibility. By providing these estimates, the framework can assist decision-makers in understanding the potential economic and environmental implications of different CCU technologies, and help in determining the most appropriate course of action for the development and scaling up of these technologies.

We provide a demonstration use of this framework to assess two commonly discussed reactions in the realm of CCU: CO₂ hydrogenation to methanol and the dry reforming of methane (DRM). The DRM reaction was assessed to be a Type 3 technology, with a CO2Fix of 0.92 and an MISR of 1.6. Furthermore, it was estimated that for CO₂ capture and sequestration cost less than 0.0.08 $/kg-CO₂, the technology can be considered a Type 1 technology. At a CO₂ capture and sequestration cost of 0.05 $/kg-CO₂ the MISR was calculated to be 1.57 at a CO2Fix of 1. The CO₂ hydrogenation reaction was assessed to be a Type 2 technology with a CO2Fix of 2 and a MISR of 0.9. The developed framework estimates that the CO₂ hydrogenation reaction can be considered a Type 1 technology with a CO₂ utilization credit above 0.073 $/kg-CO₂. Moreover, at a CO₂ utilization credit of 0.1 the reaction has an estimated MISR of 1.02.

The developed framework is a powerful means of quickly screening CCU conversion technologies at early stages of research and development, providing insights on the necessary conditions for the reaction to be economically viable and CO₂ fixing. It can also be used to generate early quantitative estimates of the economic and CO₂ fixation potential of such reactions for the purpose of comparison and optimization studies.