NOVELTY - A biogas purification system, comprises marsh gas pressurizing device (1), buffering tank (2), water washing tower (3), a dryer (4), analysis tower (5), air blower (6) and water storage tank (7).    USE - As biogas purification system.    ADVANTAGE - The system is simple, energy consumption is low, cost is low, environment-friendly, purify marsh gas, and saves water resource waste.    DETAILED DESCRIPTION - A biogas purification system, comprises marsh gas pressurizing device (1), buffering tank (2), water washing tower (3), a dryer (4), analysis tower (5), air blower (6) and water storage tank (7), where a gas pressurizing device exit gas of the buffering tank of the air inlet connected, buffering tank is a gas exit and the water washing tower of connected air inlet, a water washing tower comprise at least two layer tower body, lower most layer tower body lower end set with a liquid storage section, a liquid storage section bottom end set with a drain valve, a water washing tower of the air inlet set with liquid storage section of upper part, a liquid storage section is further set with a lower one of two a liquid level window, where the upper part of the liquid level window is located below the air inlet of a water washing tower, tower body of inner top part set with water spraying device, a water spraying device comprise spraying pipe (8) and the mounting pipe of a nozzle (9), the spray pipe the water inlet extends out of the tower body, the most upper layer tower body top part set with a demisting section, the top end of the carbon dioxide water washing tower set with exhaust valve, a discharge valve through pipeline and dryer connected, tower body is further set with a body with a viewing mirror (10), a drainage valve through pipeline and the analysis tower liquid inlet connected, the analysis tower part is set with a gas inlet, air outlet of gas inlet through a pipeline and the analysis tower, a parsing tower lower end set with a water inlet, the upper end is set with an air outlet, the analysis tower of the water outlet through pipeline is connected to the water storage, the water inlet of the water spraying tube B through a pipeline and the water distributor (11) is connected with a water distributor of the water inlet through a pipeline to the water storage tank, the water distributor is connected with water tank of a pipeline set with a pump (12).    DESCRIPTION OF DRAWING(S) - The figure shows a schematic diagram of biogas purification system.    Marsh gas pressurizing device (1)    Buffering tank (2)    Water washing tower (3)    Dryer (4)    Analysis tower (5)    Air blower (6)    Water storage tank (7)    Spraying pipe (8)    Nozzle (9)    Viewing mirror (10)