Abstract: The absorptive removal of carbon dioxide from biogas using a scrubbing liquid in which carbon dioxide is chemically bound proceeds by heating the loaded scrubbing liquid, occurring after the absorption, to a temperature at which liberation of CO2 begins. Immediately thereafter, the loaded scrubbing liquid is fed to at least one centrifugal separator for separating off the gas phase from the liquid phase, wherein methane and dissolved fractions of CO2 escape via the gas phase. After separation is complete, the gas phase is passed into the absorber unit and the liquid phase is further heated to the temperature required for desorption and fed to the desorption unit for regeneration.

Abstract: A method for treating crude gas, in particular biogas, containing methane and carbon dioxide, in order to produce methane, and a plant suitable for carrying out the method. The method includes (a) washing the crude gas with an amine-containing washing solution, thereby forming a pure gas stream of methane and water, from which water is separated by subsequent cooling and condensation; (b) compressing and heating the washing solution containing CO2 and sulfur compounds and expanding the washing solution in a first expansion stage, during a secondary reaction time of 280 to 1200 seconds and at a constant reaction temperature; (c) cooling the purified washing solution and expanding it in a second expansion stage to normal pressure, whereupon any residual amounts of soluble CO2 and sulfur compounds are separated and the completely purified washing solution is cooled to normal temperature and returned to the washing stage.

Abstract: A method for regenerating an amine-containing scrubbing solution which is obtained during gas purification and in which CO2 and sulfur compounds are chemically bonded, as well as a system that is suitable for carrying out the method. The contaminated scrubbing solution is heated, compressed, and expanded in several stages such that CO2 and sulfur compounds are separated. The expanded scrubbing solution is subdivided into two partial streams, and one partial stream is recirculated into the process.

Abstract: The absorptive removal of carbon dioxide from biogas using a scrubbing liquid in which carbon dioxide is chemically bound proceeds by heating the loaded scrubbing liquid, occurring after the absorption, to a temperature at which liberation of CO2 begins. Immediately thereafter, the loaded scrubbing liquid is fed to at least one centrifugal separator for separating off the gas phase from the liquid phase, wherein methane and dissolved fractions of CO2 escape via the gas phase. After separation is complete, the gas phase is passed into the absorber unit and the liquid phase is further heated to the temperature required for desorption and fed to the desorption unit for regeneration.

Abstract: A method for separating methane and carbon dioxide from biogas and a device are intended for purifying biogas, wherein carbon dioxide is separated off from the biogas. The method is distinguished by an energetically favorable mode of operation. The biogas is passed under atmospheric pressure and standard temperature into an absorption column. While the biogas ascends through a packed bed, which has a surface area of 600 to 1200 m2/m3, and at a space velocity of 5 to 40 Nm3/m3h, carbon dioxide present in the biogas is bound in a wash liquid by chemosorption. The purified methane gas is taken off at the top of the absorption column at a defined flow velocity. Carbon dioxide bound in the wash liquid is removed by desorption at a relatively high pressure of 2 to 30 bar and a temperature of at least 120° C. Biogas may be separated into methane and CO2.