Ecologic and Economic Evaluation of Combined Methanol Synthesis from CO2 and Biotechnological Upgrading to Value Products. Part 1: Environmental Impact

Abstract

The conversion of waste biomass with green hydrogen into methanol and subsequent biotechnological conversion of this into valuable materials could be a promising value chain. Starting from biogenic CO₂ and green H₂, methanol is produced in a first process path. This is then split into two separate process paths: methanol is used (i) in a biotechnological process with genetically modified bacteria to produce crotonic acid and (ii) to produce biomass protein. To evaluate the ecologically and economic benefits of both biological processes to the conventional production routes, first life cycle assessment and techno-economic assessment of biotechnological and chemical processes are accomplished. For this, a baseline scenario and several scenarios are calculated to investigate the influence of various parameters on environmental impact and economic efficiency. The results also identify the processes that are mainly responsible for costs and environmental impact, as well as the material, energy and waste flows, and process parameters that cause them. From this, measures and conditions for improving economic efficiency and environmental impact are derived.