Quadruple-effect solvent recovery energy-saving system and method

The invention discloses a quadruple-effect solvent recovery energy-saving system. The system comprises a first-effect recovery tower, a second-effect recovery tower, a third-effect recovery tower, a fourth-effect recovery tower, a first-effect evaporation tower, a second-effect evaporation tower, a third-effect evaporation tower, a first mother liquor raw material tank and a second mother liquor raw material tank. The method for recovering alcohol by using the system comprises the following steps: separately distilling the first mother liquor and the second mother liquor, and carrying out low-temperature distillation on the first mother liquor foamed by high-temperature distillation through the fourth-effect recovery tower and the third-effect recovery tower and distilling the second mother liquor which does not foam after high-temperature distillation through the first-effect evaporator, the first-effect recovery tower, the second-effect evaporation tower, the second-effect recovery tower, the third-effect e