Energy, Cost, and Environmental Assessments of Methanol Production via Electrochemical Reduction of CO₂ from Biosyngas

Abstract

Electrochemical reduction of CO 2 removed from biosyngas into value-added methanol (CH 3 OH) provides an attractive way to mitigate climate change, realize CO 2 utilization, and improve the overall process efficiency of biomass gasification. However, the economic and environmental feasibilities of this technology are still unclear. In this work, economic and environmental assessments for the stand-alone CO 2 electrochemical reduction (CO 2 R) toward CH 3 OH with ionic liquid as the electrolyte and the integrated process that combined CO 2 R with biomass gasification were conducted systematically to identify key economic drivers and provide technological indexes to be competitive. The results demonstrated that costs of investment associated with CO 2 R and electricity are the main contributors to the total production cost (TPC). Integration of CO 2 R with CO 2 capture/purification and biomass gasification could decrease TPC by 28%−66% under the current and future conditions, highlighting the importance of process integration. Energy and environmental assessment revealed that the energy for CO 2 R dominated the main energy usage and CO 2 emissions, and additionally, the energy structure has a great influence on environmental feasibility. All scenarios could provide climate benefits over the conventional coalto-CH 3 OH process if renewable sources are used for electricity generation.

Thermodynamic and Economic Assessments of Electrochemical CO2 Conversion to Dimethyl Ether: Trade-off between Hydrogen Gas and Water Vapor as a Proton Source

“…46 The current is calculated using a scheme where the electrical costs are inversely proportional to the Faradaic efficiency leading to higher costs at lower Faradaic efficiencies. 12 Due to the high thermodynamic and kinetic requirements for DME pathways 3 and 4, their overall OPEX increases per kWh (Figure 1). Please refer to Tables S1−S12 in the SI for detailed calculations for each pathway.…”

“…47 For industrial purposes, where current densities of 1−5 A/cm 2 are essential, cell voltages of 2−3 V versus RHE are more realistic. 48 For the electrochemical CO 2 RR to MeOH, the reaction requires a higher activation energy and is shown to need a total cell voltage of at least 3 V. 12,49 In the scenario where water vapor is used at the anode instead, the cell voltage would increase by a minimum of 1.23 V due to the standard half-cell voltage of water splitting, leading to increased electrical costs (Figures S9 and S10). Electrical costs can be minimized by reducing the cell voltage and lowering renewable electricity costs.…”

“…Eliminating the hassle and costs associated with the downstream separation and purification of chemicals substantially reduces production costs. 42…”

Techno-Economic Assessment of Amine-Based CO2 Capture Process at Coal-Fired Power Plants: Uncertainty Analysis

“…Chemical absorption is commonly performed using ethanolamine aqueous solutions, such as monoethanolamine (MEA). 13 Over the years, there has been a release of many publications on the techno-economic analysis (TEA) of CCS with a focus on MEA solvent usage in new or retrofitted coal-fired power plants. Cebrucean et al 14 conducted a performance analysis of subcritical (SubC) and supercritical (SC) coal-fired power plants while considering biomass cofiring and CO 2 capture using MEA solution.…”

“…In the chemical absorption process, CO 2 in the exhaust gas reacts with the CO 2 absorbent and then releases it after heat treatment. Chemical absorption is commonly performed using ethanolamine aqueous solutions, such as monoethanolamine (MEA) . Over the years, there has been a release of many publications on the techno-economic analysis (TEA) of CCS with a focus on MEA solvent usage in new or retrofitted coal-fired power plants.…”