City of Modesto Digester-Gas Scrubber System (Methane)

摘要

A system is described that separates methane from sewage gas. To process the raw digester gas, it is first compressed and then injected into the base of a pressurized tower (scrubber tower). As the digester gas flows up the tower, a counter flow of water removes the contaminants leaving 98% pure methane with a heating value of about 1000 BTU's per cubic foot. The water from the bottom of the scrubber tower is piped to the top of a second tower (regenerator tower). In the regenerator tower the contaminants are removed from the water and are vented to the atmosphere. The water is recirculated. The methane can be used to propell autos by pumping it into pressure tanks, usually 2400 PSI pressure. A reasonable sized tank will hold 325 cubic feet of methane which is the equivalent to 3.25 gallons of gasoline. More than one tank may be mounted on a vehicle. (ERA citation 07:050796)