Liquid hydrocarbon mercaptan removal excess gas circulation method and system

The invention belongs to the technical field of liquid hydrocarbon mercaptan removal in petrochemical enterprises, and discloses a liquid hydrocarbon mercaptan removal excess gas circulation method and a system, the circulation method comprises the following steps: rich alkali liquor and oxygen enter an alkali liquor regeneration tower from the lower part of the alkali liquor regeneration tower, and working gas enters the alkali liquor regeneration tower from the upper part of the alkali liquor regeneration tower; liquid discharged from the alkali liquor regeneration tower enters an alkali liquor settling tank, disulfide oil is discharged from the upper part of the alkali liquor settling tank, and poor alkali liquor is discharged from the bottom of the alkali liquor settling tank; overhead gas of the alkali liquor settling tank and overhead gas of the alkali liquor regeneration tower serve as circulating gas, are detected by an online analyzer and compressed by a compressor, and then enter a liquid separation