Method for increasing concentrations of acid gas hydrogen sulfide and carbonyl sulfide in low-temperature methanol washing process

The invention relates to a method for increasing concentrations of acid gas hydrogen sulfide and carbonyl sulfide in a low-temperature methanol washing process. The method comprises the following steps: (1) conducting heat exchange cooling and deamination on transforming gas from carbon monoxide conversion, sending the gas from the bottom of a methanol absorbing tower, and passing the gas a the desulfurization segment and a decarbonization segment; (2) after the decarburization segment and desulfurization segment, sending the methanol solution into an intermediate pressure flash column, conducting vacuum flash to emit carbon monoxide and hydrogen in the methanol solution, and the sending into a re-absorbing tower; (3) removing carbon dioxide in the methanol solution in the re-absorbing tower, and sending the sulfur-rich methanol solution discharged from the bottom of the re-absorbing tower to a thermal regeneration tower by a pump; and (4) removing hydrogen sulfide and carbonyl sulfide in the methanol solution in the thermal regeneration tower. The low-temperature methanol washing process is employed to optimize the operation process, and increase the operating efficiency of a subsequent sulfur recovery section. Meanwhile, the method is simple and feasible in the daily operation and increases the economic efficiency for enterprises.