Techno-Economic Analysis on an Electrochemical Non-oxidative Deprotonation Process for Ethylene Production from Ethane

Abstract

This report has been prepared as part of a study for Light Water Reactor Sustainability (LWRS) program to evaluate the technical and economic feasibility of integrating a light-water reactor (LWR) nuclear power plant (NPP) with an electrochemical, nonoxidative deprotonation (ENDP) process for production of ethylene from ethane. Process synthesis and modeling were utilized to assess the economic feasibility. ENDP is a novel, early Technical Readiness Level (TRL)~1-2 process for producing ethylene and hydrogen via the electrochemical dehydrogenation of ethane. It is currently being demonstrated at the laboratory scale at Idaho National Laboratory (INL) (Ding et al. 2018). Ethane is a plentiful feedstock that is separated as a condensate during natural-gas processing. The U.S. LWR NPP fleet is facing increasing financial challenges due to the expansion of solar and wind power, as well as the low price of natural gas. Alternative strategies are being sought to increase the revenues of NPPs and to find new applications for NPP heat and electricity during periods of overgeneration. NPPs enable solar and wind generating-capacity buildout by providing carbon-free baseload capacity needed for times when solar and wind are unable to generate. Overgeneration occurs during periods when excess electricity is generated due to high solar-or wind-energy output. During these times, NPPs are either paying to curtail wind and solar power or are flexibly operating by turning down their reactor power and generation output. Flexible operations can have impacts on NPP fuel cycles and maintenance while also decreasing revenue. An NPP could alternatively provide carbon-free energy for process-heat steam, cooling water for cooling duties, and house-load electricity to industrial processes, such as ENDP, as an alternative revenue-generating source. In conventional chemical processes, energy and utilities are generated by utilizing fossil fuels, such as coal, fuel oils, and natural gas, resulting in significant emissions of carbon dioxide greenhouse gases (GHGs). Ethylene production via the current industry-standard process of steam cracking, for example, is energy intensive and uses large furnaces burning large amounts of natural gas to "crack" feedstocks from ethane and naphtha to heavy gasoils into lighter olefinic molecules (such as ethylene, propylene, etc). Steam cracking is a mature and optimized industrial process, but remains both capital and energy intensive. Thus, the steam-cracking process is the subject of frequent process-intensification studies to reduce the process-energy demand (Gao et al. 2019). The primary purpose of this report is to present a scaled modeling and technoeconomic analysis (TEA) of the novel ENDP process for producing ethylene and hydrogen from ethane. This TEA provides the related chemical process and economic analysis for the production of ethylene and hydrogen via the ENDP process and compares it with conventional industrial steam cracking of ethane for ethylene production. The modeled ENDP process is co...

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