Self-recuperative high temperature co-electrolysis-based methanol production with vortex search-based exergy efficiency enhancement

The reduction of greenhouse gas emission via the transformation of carbon dioxide into methanol results in several secondary benefits including the production of a valuable by-product that can be used for energy storage and as a fuel source. As such, this is a promising approach for mitigating climate change. Methanol production via the co-electrolysis process using solid oxide electrolyzer cells is an efficacious solution to the issue of excess electricity storage in the context of renewable energy and carbon dioxide utilization. However, this process is an energy-intensive and temperature-sensitive method, mainly due to the requirement of high-temperature electrolysis. In this context, this study investigates and evaluates the potential for overall performance improvement by minimizing energy consumption and increasing methanol production using self-heat recuperation technology. The newly developed vortex search strategy was employed to achieve the maximum potential benefit from retrofitted recuperators. Detailed exergy analysis was performed for the process and the evaluation of its performance. The findings revealed that the electrochemical system for co-electrolysis has the highest exergy destruction rate. By employing the vortex search approach, the exergy loss of the energy process system can be reduced by 61.7% with a total reduction of the exergy loss of 15.9%, while improving methanol production and decreasing distillation reboiler duty. The simple solution of self-recuperation with optimization that was utilized in this study is a flexible approach that can be directly applied to the improvement of co-electrolysis and methanol synthesis. (C) 2019 Elsevier Ltd. All rights reserved.