METHANE CONCENTRATION METHOD AND METHANE CONCENTRATION DEVICE OF BIOGAS

摘要

PROBLEM TO BE SOLVED: To highly concentrate methane from a biogas and to further effectively utilize methane included in the biogas.SOLUTION: The biogas is pressurized and supplied to a first stage separation membrane module 1 via a supply tube 4 and a first compressor 5, a transmitted gas transmitted through the module 1 and containing carbon dioxide much is compressed by a second compressor 9 via a transmission gas tube 7 and cooled by a cooler 10 to liquefy and recover carbon dioxide and residual transmitted gas supplied to a gas engine 26 to be utilized. A non-transmitted gas which is not transmitted through the first stage separation membrane module 1 and contains methane much is supplied to a second stage separation membrane module 2 by residual pressure via a non-transmission gas tube 8 and a transmitted gas transmitted through the module 2 and containing carbon dioxide much is recycled to the first stage separation membrane module 1 via a recycle tube 11 and the supply tube 4 and a non-transmitted gas which is not transmitted through the second stage separation membrane module 2 and contains methane much is recovered as a methane concentrated gas in a recovering tube 12.