Techno-economic analysis of fermentation carbon dioxide utilization for hydrocarbon blend-stock production in corn ethanol refineries

The increasing demand for sustainable fuels has driven interest in using fermentation carbon dioxide from corn ethanol refineries to produce gasoline-range hydrocarbons, offering both carbon emission reductions and economic benefits for existing refineries. While various carbon dioxide utilization technologies have been explored, ethanol dry reforming integrated with methanol-to-gasoline for direct gasoline production has not been extensively studied in terms of economic viability and scalability. This study hypothesizes that combining these processes in a corn ethanol refinery can provide a more economically viable and scalable solution compared to traditional indirect hydrogenation pathways by reducing hydrogen dependency and improving utilization. Aspen Plus simulations modeled both pathways integrated with methanol synthesis and coupled to methanol-to-gasoline for producing denatured ethanol and E85. A techno-economic analysis evaluated net present value and the levelized cost of production, while a life-cycle assessment quantified carbon dioxide emissions and the impact of policy incentives. The dry reforming pathway reduced hydrogen requirement from 0.53 to 0.26 kg/kg of gasoline compared to indirect hydrogenation, but at the expense of reduced output. Denaturant production from the hydrogenation pathway is more economically viable, with a net present value of $332.02 million and a production cost of $1.69 per gallon. In conclusion, denatured ethanol from indirect hydrogenation is the most suitable option for short-term commercialization, but dry reforming of ethanol offers long-term scalability by reducing hydrogen dependence and enhancing carbon dioxide utilization.