The utility model provides a
methanol rectification device based on multi-effect
thermal coupling. The
methanol rectification device comprises a pre-rectification
tower, a negative pressure rectification
tower, a pressurization rectification
tower, a secondary pressure rectification tower and a normal pressure rectification tower which are connected in sequence, the pre-rectifying tower, the pressurized rectifying tower, the secondary-pressure rectifying tower and the normal-pressure rectifying tower are respectively provided with a pre-tower
reboiler, a pressurized tower
reboiler, a secondary-pressure tower
reboiler and a normal-pressure tower reboiler, the lower part of the negative-pressure rectifying tower is provided with a first negative-pressure tower reboiler and a second negative-pressure tower reboiler, and a
gas phase extracted from the top of the secondary-pressure rectifying tower provides heat for the pre-tower reboiler; a
gas phase extracted from the top of the pressurized rectifying tower provides heat for a secondary pressure tower reboiler and an atmospheric tower reboiler respectively; a
gas phase extracted from the top of the pre-rectifying tower provides heat for a negative pressure tower reboiler I; a gas phase extracted from the top of the normal-pressure rectifying tower provides heat for a negative-pressure tower reboiler II; the energy utilization efficiency in the
methanol rectification process can be remarkably improved, the production cost is reduced, the environmental
pollution is reduced, and remarkable economic and
social benefits are achieved.