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Techno‐economic comparison of biogas cleaning for grid injection, compressed natural gas, and biogas‐to‐methanol conversion technologies
Author(s) -
Sheets Johnathon P.,
Shah Ajay
Publication year - 2018
Publication title -
biofuels, bioproducts and biorefining
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.931
H-Index - 83
eISSN - 1932-1031
pISSN - 1932-104X
DOI - 10.1002/bbb.1848
Subject(s) - biogas , methanol , anaerobic digestion , waste management , natural gas , pulp and paper industry , methane , compressed natural gas , environmental science , chemistry , engineering , organic chemistry
Technologies to upgrade biogas to value‐added products have great potential to reduce greenhouse gas emissions and provide economic benefits. However, the costs of conventional upgrading methods, such as purification for natural gas grid injection or compressed natural gas (bio‐CNG), have not been compared to the thermochemical or biological conversion of biogas to methanol. This study compared the techno‐economic feasibility of upgrading biogas from a large‐scale landfill or anaerobic digestion (AD) facility (5900 Nm 3 /h) to: 1) purified biogas (>97% CH 4 ) for grid injection; 2) bio‐CNG; 3) methanol via thermochemical conversion; and 4) methanol via biological conversion using methanotrophs (methane‐oxidizing bacteria). Bio‐CNG had the highest net present value (NPV) ($43 million), followed by purified biogas ($80 000), biological methanol production (−$303 million), and thermochemical methanol production (−$358 million). Methanol costs were slightly lower for thermochemical conversion ($2.11/kg methanol, 1.99/kg after credits) compared to biological conversion ($2.24/kg methanol, $2.19/kg after credits) because the thermochemical technology had higher methanol production rates. Sensitivity analysis indicated that biological conversion costs can be lowered if methanotrophs are modified to have higher CH 4 oxidation rates and higher tolerance to methanol, and if formate costs are reduced. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd