California Bioenergy LLC Receives a US Granted Patent for its Biogas to Bioelectricity Process
A patent has been granted to California Bioenergy LLC for the processing of biogas to electricity (“bioelectricity”) in fuel cells. (Buckenham & Waineo, 2022). The company’s primary business is in the processing of dairy farm waste using its CalBio™ anaerobic digester technology which includes an option to convert biogas into electricity using fuel cells or internal combustion engines. (Calbio Energy).
The patent describes a system which has a biogas purification stage followed by conversion to electricity in a solid oxide fuel cell (SOFC) operating at less than 750˚C . The purification stages remove carbonyl sulfides, hydrogen sulfide and entrained water as shown in Figure 1 below. The sorbents used are iron sponge or iron impregnated onto wood chips for bulk H2S removal followed by a bed of activated carbon which acts as an H2S polisher. After dehumidification and oil removal, a bed of copper oxide polishes out carbonyl sulphide (COS). The purified biogas has a methane content of ~60% and the balance is CO2.
The electricity subsequently generated in the SOFC can be supplied to the grid or used to power vehicles. The data management package tracks energy credits in real time and assigns them to the customer. The CO2 and water by-products are reused within the farming operations which improves the overall circularity of the process.
Buckenham, N. R., & Waineo, D. (2022, December 6). US11517853B2. System for processing of biogas to produce electricity in fuel cells.
Calbio Energy. (n.d.). Calbio Projects. Retrieved from Calbio Energy: https://calbioenergy.com/projects/