Effect of Moisture on Methane Permeation Through Fermenter Covering Films in Biogas Plants

Abstract

Abstract Methane permeation through polyamide and polyethylene mono and multilayer films has been measured via direct coupling of a gaschromatograph with a permeation measurement cell. Methane permeabilities [in cm3 (STP)·mm·d−1·bar−1·m−2] for single films were found to be 335 for polyethylene (PE) at 40°C, 0.64 for polyamide (PA) 6/6.6 with dry gas and 8.7 for PA 6/6.6 with water vapour saturated test gas. As a result, under operating conditions of biogas production facilities (40°C, water vapour saturated), the replacement of PE by PA, as biogas membrane on top of a fermenter, can reduce methane emission through permeation by a factor of about 40.