Integrating indirect CO2 hydrogenation with coal-based chemical industry: Energetic and environmental assessment of a novel low-carbon methanol strategy

As a major source of global CO2 emissions, the chemical sector faces significant decarbonization challenges, particularly in methanol production, which is a highly carbon-intensive process that relies heavily on coal-based techniques. This study proposes an innovative methanol production pathway that integrates indirect CO2 hydrogenation with conventional coal-based methanol synthesis to improve energy efficiency and significantly reduce greenhouse gas emissions. The proposed system strategically incorporates green hydrogen, generated from renewable electricity, to convert captured CO2 into methanol, thereby partially substituting fossil-based carbon inputs. Comprehensive energetic results indicates that the integrated process demonstrates a superior energy efficiency of 57.38 %, a carbon conversion ratio of 95.68 %, and a coal saving ratio of 20.27 %. These improvements can result in a notably reduction in carbon emissions for coal-based menthol production. Life cycle assessment indicates that the proposed process achieves a global warming potential of 1.30 kg CO2-eq per kg methanol, representing a 70.5 % reduction compared to the conventional coal-based methanol process. Furthermore, the integrated system exhibits superior performance across multiple environmental indicators, including life cycle primary energy demand and water consumption, when benchmarked against conventional production processes. This study demonstrates a low-carbon methanol production method combining CO2 utilization and renewable energy, which offers a progressive decarbonization pathway for methanol production.