Pipeline-Quality Methane from Anaerobic Digestion Systems

"Large farms and feedlot operations produce large quantities of manure in a small area. Anaerobic digester units capable of producing pipeline quality methane installed at each farm or dairy could be instrumental in eliminating the difficulties associated with the transport of manure off site. If consumed properly, use of manure-derived fuels can also protect against environmental problems such as groundwater leaching and greenhouse gas emissions (methane emission) associated with land filling of the farm wastes. The use of anaerobic digester gas reduces the amount of methane emitted into the atmosphere and provides a new and untapped resource of energy. TDA Research, Inc. (TDA) proposes to develop an vacuum swing adsorption (VSA) based system for upgrading the biogas produced from farm wastes to pipeline specifications. TDA’s system uses a novel low cost, high capacity CO2 adsorbent to convert the biogas to pipeline quality methane. The vacuum swing adsorption process results in a low methane loss, 95% of the methane entering the separation unit is sent ti the Further, the unit has very low operating and capital costs. Results: Successful completion of Phase I will result in the demonstration of the feasibility of TDA’s VSA system to produce pipeline quality methane from biogas and show its economic viability. In Phase II TDA will build and test a sub-scale prototype unit and scale up production of the sorbent. Potential Commercial Applications: This technology will enable the animal and dairy farms to solve a major waste “manure” handling problem. This will also provide a cheaper way to upgrade the biogas to a high-value fuel, pipeline methane that can be exported from the farm. It will also find use in waste water treatment or any other facilities that may use anaerobic digestion and want to sell pipeline quality natural gas instead of burning the gas on-site. Key Words: Waste-to-energy, Biogas, Pipeline methane, Adsorption, CO2 removal, Methane emissions "