NOVELTY - The device for the separation of methane from methane-containing mixtures e.g. biogas, comprises a plate-type heat exchanger (21) with an inlet and outlet for cooling agent, a separation chamber (43), which encloses the heat exchanger and comprises an outlet for gaseous methane, a liquefaction unit (16), a line (17) for liquefied methane, a line (46) for gaseous methane, a discharge system for non-methane containing components, and a pretreatment mechanism for cooling the mixtures. The components of mixtures have a higher boiling-, melting- or a sublimation temperature than liquid methane.    USE - Device for the separation of methane from methane-containing mixtures such as biogas, gas from purification plants, fermentation gas or firedamp.    ADVANTAGE - The device ensures effective separation of methane with lower energy consumption by saving a large amount of the energy used to the gas processing during the gas liquefaction and or the gas cleaning.    DETAILED DESCRIPTION - The device for the separation of methane from methane-containing mixtures e.g. biogas, comprises a plate-type heat exchanger (21) with an inlet and outlet for cooling agent, a separation chamber (43), which encloses the heat exchanger and comprises an outlet for gaseous methane, a liquefaction unit (16), a line (17) for liquefied methane, a line (46) for gaseous methane, a discharge system for non-methane containing components, and a pretreatment mechanism for cooling the mixtures. The components of mixtures have a higher boiling-, melting- or a sublimation temperature than liquid methane. The line for liquefied methane connects the liquefaction unit with the cooling agent inlet. The line for gaseous methane connects the liquefaction unit with the cooling agent discharge opening and with the discharge opening for the gaseous methane of the separation chamber. The heat exchanger has a smooth surface, and comprises a heating element. The line for liquid methane and the line for gaseous methane comprise a valve. The discharge system comprises a collecting trough, a piston, a gate valve and a discharge line. The pretreatment mechanism comprises a cooling circuit with a heat exchanger for cooling the cooling agent in the cooling circuit and with two heat exchangers for cooling the mixture, a line loop with two inlets for the uncooled mixture, and a discharge opening for the pre-cooled mixture. The line loop comprises two valves, where the first valve is arranged between the first inlet for the uncooled mixture and the discharge opening for the pre-cooled gas mixture, and the second valve is arranged between the second inlet for the uncooled mixture and the discharge opening for the pre-cooled mixture. The heat exchanger for cooling the cooling agent comprises a container with an inlet for the cooling agent, a discharge opening for the cooling agent, and an inlet for dry ice. The device includes a tank for collecting liquid methane and a connection to a gas network, where the tank is connected with the line for liquefied methane by a three-way regulator and the connection is connected with the line for gaseous methane by another three-way regulator or is arranged directly. The cooling agent is ethanol. An INDEPENDENT CLAIM is included for a procedure for the separation of methane from methane-containing mixtures.    DESCRIPTION OF DRAWING(S) - The diagram shows a cross-sectional view of a device for the separation of methane.    Liquefaction unit (16)    Line for liquefied methane (17)    Heat exchanger (21)    Separation chamber (43)    Line for gaseous methane. (46)