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.