Enhancing Biomass-to-Liquid conversion through synergistic integration of natural gas pyrolysis: process options and environmental implications

• Published in: Energy conversion and management 2024-02, Vol.302, p.118142, Article 118142
• Main Authors: Ostadi, Mohammad, Zang, Guiyan, Bromberg, Leslie, Cohn, Daniel R., Gençer, Emre
• Format: Article
• Language: English
• Subjects: administrative management; Biomass gasification; byproducts; carbon; combustion; electrolysis; endothermy; energy conversion; feedstocks; gasification; greenhouse gas emissions; greenhouse gases; greenhouses; heat; hydrogen; life cycle assessment; liquids; methane; Methane decomposition; methanol; natural gas; Natural gas pyrolysis; prices; Process integration; pyrolysis; Renewable fuel; synthesis gas; transportation; woody biomass
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2024.118142

[Display omitted] •Framework for integrating pyrolytic hydrogen with biomass gasification to methanol process.•Assessment of process parameters for ”hydrogen-enhancement” of biomass to methanol.•Methanol cost ∼ $440-$470/tonne for biomass gasification and natural gas pyrolysis.•Fugitive methane from the natural gas supply chain is a key contributor to GHG emissions. Low-carbon liquid fuels are needed to reduce greenhouse gas emissions in sectors reliant on liquid fuels/chemicals, such as transportation as well as other difficult to electrify sectors. A range of biomass feedstocks is a renewable carbon source which holds substantial promise for generating low-carbon liquid fuel through, for example, the Biomass-to-Liquid (BTL) gasification process. However, biomass availability is limited, and it is hydrogen-lean; consequently, syngas generated from biomass through gasification is hydrogen deficient for converting all of the biomass carbon to methanol. By supplementing external low-carbon hydrogen, in other words ”hydrogen-enhancement”, the biomass carbon conversion efficiency of the process can be increased by around a factor of two for methanol. Production of low-carbon hydrogen from natural gas pyrolysis is showing promise as a substantially lower cost alternative to widely known water electrolysis. Because of the endothermic nature of natural gas pyrolysis reaction, providing the heat required by the process impacts the carbon and thermal efficiencies of the overall biomass to liquid fuel process. We have developed a framework in which five different integration options of natural gas pyrolysis within a thermochemical biomass to fuel process are analyzed. As an illustrative case for the developed framework, methanol production from an illustrative biomass feedstock (woody biomass) is considered. The five integration options considered include natural gas combustion, syngas combustion, hydrogen combustion, heat integration within the process (no external heating), as well as electrical heating to provide heat for the pyrolyzer. Technoeconomic and net greenhouse gas (GHG) analyses of each of these options on the methanol production are performed. The technoeconomic analysis indicates that for an illustrative pyrolysis process using molten material, the costs of methanol that is produced is in the range of ∼ $440 to $470/tonne (assuming sale of the byproduct carbon at a price of $100/tonne carbon; without sale of the carbon byproduct, the cost would be in