Method and device for recycling and extracting lightweight oil to regenerate methanol

The invention discloses a method and a device for recycling and extracting lightweight oil to regenerate methanol. The method comprises the following steps: S1: cooling and condensing oil-containing coal gas to separate out lightweight oil; S2: separating oil coal gas by adopting a pre-washing tower, and cooling the cooled and condensed to a set temperature; S3: introducing the cooled coal gas to a methanol pre-washing tower, and adopting cold methanol to wash and absorb the coal gas; S4: heating the methanol which absorbs the lightweight oil and then discharging the methanol into a flash evaporator to perform gas separating and recycling; S5: discharging water and methanol discharged out of the flash evaporator into an extractor for extracting to obtain an oil phase and a water phase; S6: rectifying the water phase to separate out lightweight oil and a methanol solution, and returning the separated lightweight oil back to an extractor for extraction; and S7, rectifying the methanol solution to separate out methanol and water. The method disclosed by the invention is high in lightweight oil recovery rate and the recovered lightweight oil is high in quality.