Techno-economic evaluation of pyrolysis and electrolysis integration for methanol and char production

The pyrolysis technology enables the conversion of biomass into different products, such as char, oil, and synthesis gas. These products can play an important role in the decarbonization of agriculture, industry, and transportation, but are challenged by the availability of biomass and low fuel productivity. Electrolysis technologies, such as alkaline or solid oxide electrolysis, can help to overcome these drawbacks by supplying hydrogen derived from renewable sources. This paper focuses on providing the modeling, methods, and analysis necessary to pinpoint the benefits and challenges of this process concept. Integrating electrolysis with pyrolysis greatly improves the carbon conversion efficiency from 65 % to 97.1–97.8 % by increasing the methanol production by 2.7 times. For instance, the integration of co-electrolysis (i.e., CO2 and H2O electrolysis) and pyrolysis can increase carbon conversion from 65 % up to 98 %, while attaining a maximum energy efficiency of 67 % (for methanol production). Moreover, projected methanol production costs are estimated to vary between 706 and 922 USD/t for current technology prices. Char plays an important role in abating biomass costs and enabling net negative emissions in methanol production (−0.62 to −1.02 tCO2/tCH3OH). Further improvements can be achieved by optimizing electrolysis operating conditions and by reducing energy consumption in distillation and CO2 capture.