Techno-Economic Assessment of Biogas-to-Methanol Processes Coupled with Low-Carbon H₂ Production Technologies

In order to realize carbon mitigation and the efficient utilization of waste biogas, the biogas-to-methanol process is an important method. The syngas produced by the conventional biogas reforming technology is rich in CO₂ and CO, whereas it is poor in hydrogen. Therefore, additional H₂ is introduced into the system to adjusted the syngas ratio, promoting the efficient conversion of the biogas. However, the use of traditional H₂ production technologies generally results in considerable carbon emissions. Given these points, low-carbon H₂ production technologies, namely methane pyrolysis technology and chemical looping reforming technology, are integrated with the biogas-to-methanol process to enhance carbon conversion, carbon reduction, and cost-saving potentials. Comprehensive technical and economic comparisons of the integrated processes are conducted. The process coupled with chemical looping reforming technology has a higher carbon conversion efficiency (73.52%) and energy efficiency (70.41%), and lower unit carbon emissions (0.73 t CO₂/t methanol). Additionally, the process coupled with methane pyrolysis technology has higher product revenue, whereas that including chemical looping reforming technology has a lower net production cost (571.33 USD/t methanol). In summary, the novel chemical looping reforming technology provides a cleaner and more sustainable pathway with which to promote the efficient conversion of biogas into methanol.