(219c) Evaluating CO2-to-Olefins Conversion Using Nuclear Energy: A Modeling and TEA/LCA Approach

Light olefins, such as ethylene and propylene, are essential chemicals widely used in various industries. Traditionally, light olefins are produced through steam cracking of fossil fuels, such as ethane, natural gas liquid and naphtha, etc., these process usually results in substantial greenhouse gas (GHG) emissions. To explore more sustainable alternatives, we developed a novel process to produce ethylene and propylene from carbon dioxide (CO₂) and hydrogen (H₂) utilizing nuclear energy for electricity and onsite H₂ generation. We designed and modeled this alternative pathway using Aspen Plus software to produce low carbon ethylene and propylene by coupling CO₂-to-methanol process and methanol to olefins (MTO) technology, both processes are relatively high technology readiness level (TRL) technologies.

Using 1 GWe nuclear energy, the conceptual plant can produce 635 metric tons of ethylene and 434 metric tons of propylene per day, achieving a carbon conversion rate of 98.2%, and an energy efficiency (relative to electricity input) of 66%. We conducted a life cycle analysis using Argonne National Laboratory’s GREET (Greenhouse gases, Regulated Emissions, and Energy use in Technologies) model to assess the well-to-gate (WTG) GHG emissions of produced olefins. The results range from -2.94 to -3.09 kgCO₂e/kg Olefins depending on the CO₂ feedstock sources, indicating a significant reduction compared to fossil-based olefins. The techno-economics of this light olefins production process were conducted by using a discounted cash flow analysis. With electricity cost of $70/MWh and H₂ cost of $3.8/kg, the levelized production costs of ethylene and propylene are $1.6/kg and $3/kg, respectively, without considering any tax credit. Considering the potential tax credit of 45Q for CO₂ utilization, the ethylene and propylene levelized cost was $1.5/kg and $2.8/kg, respectively. The cost of H₂ is the most impactful economic variable. When the H₂ cost decreases to $1/kg, the levelized production cost of light olefins could be comparable to the market olefins prices.