Technique for joint production of methanol and natural gas with methyl hydride containing synthesis gas

The invention belongs to the technology field of coal gasification comprehensive utilization and provides particularly a technique for preparing methanol and natural gas from methane-containing synthetic gas. The technique can overcome the shortcomings of a processing scheme of methanol in synthetic gas in the prior art; and the technique comprises the following steps: methane-containing synthetic gas is pressurized and then mixed with recycle gas from a methanol synthetic tower to synthesize methanol; the methanol-containing gas from the methanol synthetic tower is heat-exchanged with the gas mixture fed into the tower and cooled, and methanol is separated; a part of the methanol-separated gas as purged gas is introduced into a methane synthesizing device, and the other part is introduced into the methanol synthetic tower to continuously react to obtain natural gas after it is pressurized via circulator, recycled and then mixed with the methane-containing synthetic gas. The technique combines synthesis of methanol of high CH4 inert gas and production of natural gas by re-synthesizing methane from purged gas obtained from methanol synthesis. With the technique, two synthesis pressures and heat energy utilization can be combined together; thus making full use of the material and achieving the purposes of saved investment, energy and consumption and good benefit.