NOVELTY - Hydrogen sulfide and carbon dioxide are removed from methane using a pretreatment tank installed with sodium hydroxide solution having pH of 11-13. Methane generated by garbage landfill, anaerobic digestion of organic waste or high-concentration organic wastewater is passed through sodium hydroxide solution and carbon dioxide. Solid methane is produced using high pressure reaction kettle and distilled water including surfactant as reaction liquid, after supercharging and flow control.    USE - Manufacture of methane gas.    ADVANTAGE - The methane gas is easily, safely, reliably and economically manufactured without affecting environment.    DETAILED DESCRIPTION - Hydrogen sulfide and carbon dioxide are removed from methane using a pretreatment tank installed with sodium hydroxide solution having pH of 11-13. Methane generated by garbage landfill, anaerobic digestion of organic waste or high-concentration organic wastewater is passed through sodium hydroxide solution and carbon dioxide. Methane which is free from carbon dioxide and sodium hydroxide by pretreatment is stored in gas storage bag. Methane from gas storage bag is compressed by a compressor to improve pressure, and transmitted to a methane buffer tank. The outlet of buffer tank is installed with a pressure relief valve for controlling and adjusting pressure of outlet of buffer tank. Methane passing through pressure relief valve is passed through a flow control pipeline with a mass flow meter and transmitted to a high-pressure reaction kettle. Device for generating solid methane is high-pressure reaction kettle. The reaction liquid is 1/4-1/5 of volume of reaction kettle. The reaction liquid is distilled water including surfactant. The methane flows out from buffer tank, after supplying methane through pressure relief valve and flow control pipeline, methane is supplied to reaction kettle and stirred by a stirring device. The rotating speed for stirring is 100-500 revolutions per minute. The stirring time is 30-50 minutes. The kettle of reaction kettle is jacket type kettle. The jacket is installed with a refrigerant. The temperature of the reaction kettle is controlled to 4-20 degrees C via heat exchange action of inner wall of reaction kettle. The pressure in reaction kettle is controlled to 2-6 MPa. When mass flow meter in the flow control meter does not display the gas flux, the reaction of the solid methane is completed. When all gas passage valves are closed, an exhaust pressure relief valve is slowly opened to relive pressure. When the pressure in the reaction kettle is reduced to 0, valve on the bottom of the reaction kettle is opened and the solid methane is discharged into the storage container.