NOVELTY - Methane with hydrogen sulfide is stored and buffered by wet spiral gas cabinet, and methane is pressurized by methane blower fan and transmitted. The hydrogen sulfide flows to the tower bottom is absorbed using washing liquid, washing liquid is transmitted to bioreactor, and temperature is maintained. Carbon dioxide in airflow is absorbed, and defoamer at the top of the carbon removal tower leaves carbon removal tower from the tower top. The carbon dioxide is flashed, and mist foam of low pressure flashing gas is separated by low flashing separator.    USE - Method for separating methane.    ADVANTAGE - The method efficiently separates methane with high purification degree and automation degree, and reduced energy consumption.    DETAILED DESCRIPTION - Methane with high concentration of hydrogen sulfide (4%(v/v)) is stored and buffered by a wet spiral gas cabinet at 20-40 degrees C under pressure of 1.5-2.5 KPa, and then the methane is pressurized to 30 KPa by a methane blower fan and transmitted to a biological washing tower. The methane has counter current contact with washing liquid from up to down in the washing tower. The high concentration hydrogen sulfide in the methane is absorbed, and desulfurated methane is discharged from the top of washing tower. The hydrogen sulfide flows to the tower bottom is absorbed using washing liquid, the washing liquid is transmitted to a bioreactor by a pump, and temperature in the reactor is maintained at 25-45 degrees C. An air distribution system at the bottom of the bioreactor supplies the oxygen to microorganism, namely thiobacillus, and sulfide dissolved in the reactor is converted to simple substance sulfur. The alkali in the washing liquid is biologically regenerated to circulate and wash, and the simple substance sulfur is transmitted to a sulfur precipitator by the pump. The simple substance sulfur and washing liquid are separated, the simple substance sulfur is transmitted to the back end system to carry out further treatment by the pump and recycled. The concentration of hydrogen sulfide in the methane treated by the biological washing tower is reduced to be less than 300 ppm. The methane after the biological desulfuration treatment is transmitted to the chemical desulfuration tower at 20-40 degrees C, and the gas has counter current contact with desulfuration poor liquid sprayed from the top of the desulfuration tower from down to top. The soda ash in the desulfuration poor liquid and hydrogen sulfide in the gas are reacted to generate sodium bisulfide such that hydrogen sulfide is removed in the gas, and content of hydrogen sulfide in the gas is reduced to 10 mg/m3 or less. The desulfurated methane is discharged from the top of the desulfuration tower, and drop in the gas is separated by a separator to be transmitted to a carbon removal section. The rich liquid at the bottom of the desulfuration tower and the unreacted desulfuration poor liquid enter a rich liquid tank from the bottom of the desulfuration tower are pressurized to 0.35-0.45 MPa by the rich liquid pump and transmitted to a regenerating groove ejector when the rich liquid passes through an ejector nozzle at high speed. The negative pressure is formed at an ejector suction chamber to suck the air automatically, and the poor liquid and air two phase flows through an ejector throat pipe and diffusion pipe, and discharged by a tail pipe, and flow upwards from the bottom of the regenerating groove. The sodium bisulfide in the rich liquid and air are reacted to form simple substance sulfur, and the suspended simple substance sulfur is subjected to air flotation to form foam floating on the upper portion of the regenerating groove. The regenerated poor liquid is pumped to the desulfuration tower by the poor liquid pump for recycling, and the sulfur foam separated from the upper portion of the regenerating groove flows into a foam groove and pumped into the smelting sulfur kettle by the foam pump. The sulfur foam in the smelting sulfur kettle is heated at 135-145 degrees C by steam to form smelted fluid, and the fluid is discharged from the outlet of the smelting sulfur kettle and cooled to normal temperature to form a sulfur product on sale. The methane at normal temperature is compressed to 1-4 MPa to enter a gas exchanger, and cooled by low pressure flashing gas in a sequential process, namely carbon dioxide and carbon removal gas, namely natural gas to 8-11 degrees C. The condensed water is separated by the separator and enters in a carbon removal tower from the bottom, and gas is in contact with carbon removal liquid at -4 degrees C to -5 degrees C from up to down in the tower in the upward flow process. The carbon dioxide in the airflow is absorbed, and a defoamer at the top of the carbon removal tower leaves the carbon removal tower from the tower top. The mist foam is separated by a carbon removal separator, heat is exchanged to room temperature by the gas heat exchanger and transmitted to the user by an off-site pipeline. The rich liquid absorbing the carbon dioxide flows out from the bottom of the carbon removal tower and is decompressed to 0.4-0.6 MPa to enter a high pressure flashing tank. Some methane and carbon dioxide in the rich liquid are flashed in the high pressure groove, the mist foam of high pressure flashing gas is separated by a high flashing separator and enters into a raw gas compressor to be compressed to the carbon removal tower. The carbon dioxide is flashed, mist foam of low pressure flashing gas is separated by the low flashing separator and enters into a carbon dioxide purifier. The level of the desulfuration tower is 1/10. The alkalinity of desulfuration poor liquid is 0.2-0.4 mol/L. The pH value of desulfuration liquid is 8.5-9.2. The circulation amount of desulfuration liquid is 250 Nm3/hour. The level of the carbon removal tower is 50-80%. The level of high pressure flashing tank is 50-95%. The pressure of the high pressure flashing tank is 0.4-0.6 MPa. The rich liquid from the bottom of the high pressure flashing tank contains large amount of carbon dioxide to enter the low pressure flashing tank. The level of the low pressure flashing tank is 25-50%. The pressure of low pressure flashing tank is 0.401-0.05 MPa. An INDEPENDENT CLAIM is included for device.