NOVELTY - A methane and carbon dioxide separating method involves desulfurizing and dedusting marsh gas, and conveying the marsh gas to a desulfurizing tower. Carbon dioxide, small dosage of methane, nitrogen and hydrogen sulfide in the marsh gas are absorbed by an adsorbent. A pregnant solution is decompressed and conveyed to a low flash groove to recycle the carbon dioxide. The carbon dioxide gas is stored in a gas storage bottle. The gas is discharged from a top part of a regeneration tower with air to reduce a residual gas content in the adsorbent solution, and the adsorbent is regenerated.    USE - Method for separating methane and carbon dioxide from marsh gas.    ADVANTAGE - The method enables separating the methane and the carbon dioxide from the marsh gas with low energy consumption, low poison, and high purity in a simple and safe manner. The method enables realizing low carbon and economic recycling function and preventing environmental pollution.    DETAILED DESCRIPTION - A methane and carbon dioxide separating method involves desulfurizing marsh gas generated during refuse filling and organic waste anaerobic digestion process through iron oxide in a desulfurizing tower, dedusting the marsh gas through a sponge in a dedusting device, and dewatering the marsh gas through silicon gel and molecular sieve in a dewatering device to adjust volume sum of methane and carbon dioxide to 97 % of the total volume of the marsh gas. The marsh gas is compressed through a compressor and conveyed to an absorbing tower to separate the methane. The marsh gas is conveyed to the tower from a bottom part of the tower to form counter current contact with adsorbent sprayed from the absorbing tower from top down. Carbon dioxide, small dosage of methane, nitrogen and hydrogen sulfide in the marsh gas are absorbed by the adsorbent. The methane in the marsh gas is retained in the gas form to separate the methane. The separated methane is discharged from the top part of the tower and stored in a gas storage cylinder after being exchanged with heat by a heat exchanger to be used. The adsorbent adsorbed with the carbon dioxide and the small dosage of methane and nitrogen is named as a pregnant solution. The pregnant solution is conveyed to a high flashing groove to be flashed to remove the small dosage of methane and nitrogen in the adsorbent. Pressure emergently is decreased after the pregnant solution enters the flashing groove, and the methane and the nitrogen with low solubility are immediately flashed out from the pregnant solution. The flashed gas is named as high flash gas in total. The high flash gas is discharged from a top part of the flashing groove. The high flash gas is flowed back to a marsh gas pipeline on a front end of the compressor to reduce the methane loss during treatment process, and the methane is recycled in the tower after the pressurization process. The pregnant solution is decompressed by a low flash decompression valve and conveyed to a low flash groove to recycle the carbon dioxide. The carbon dioxide is recycled in the low flash groove, the pregnant solution treated in the high flash procedure is conveyed to the low flash groove, the pressure is emergently decreased, and the carbon dioxide gas is flashed out from the pregnant solution and discharged from a top part of the low flash groove. The carbon dioxide gas is stored in a gas storage bottle through a pressure stabilizing valve to be transported, where the volume of the carbon dioxide is 98 % larger than that of the gas. The adsorbent solution with flashed out carbon dioxide by the low flash groove is conveyed to a regeneration tower to remove the residual gas. The adsorbent solvent is sprayed from a top part of the regeneration tower, air is blown into the regeneration tower from the bottom part, and the pressure of the residual gas contained in the adsorbent solvent is decreased under the air flow action blown by the blower to separate out the gas from the solvent. The gas is discharged from the top part of the regeneration tower with the air to reduce the residual gas content in the adsorbent solution to be lower than 0.05 % (volume ratio), and the adsorbent is regenerated.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view illustrating a method for separating methane and carbon dioxide from marsh gas. '(Drawing includes non-English language text)'