FIELD: process engineering.
SUBSTANCE: invention relates to biogas cleaning for extraction of methane containing, for example, carbon dioxide, compounds of sulfur and ammonium to be separated at several process step. Proposed method is implemented at three steps. At first step, biogas is forced through contact column K1 in counterflow with sweet water wherein carbon dioxide, hydrogen sulphide, ammonium and other organic water-soluble substances are fixed in sweet water while methane gas is bled at contact column head. At second step, dissolved methane is removed at first evaporator K2 by adding aerating air or aerating air and oxygen. At third step, dissolved carbon dioxide is removed at second evaporator K3 by adding aerating air. Note here that cleaned cleaning solution is discharged along with used gas fed to column K1. Proposed system comprises contact column K1, first evaporator K2 and third evaporator K3. Note here that contact column and evaporators are connected in series while second evaporator bottom is connected with contact column head of line 04 with cleaning solution.
EFFECT: better extraction of methane, reduced power consumption.
18 cl, 2 dwg, 2 ex
