Abstract: A system and method for improving the water quality of a dehydration tower in a purified terephthalic acid device includes a dehydration washing device, a tail gas condensation device communicating with the top of the dehydration washing device, and a water separation device communicating with the tail gas condensation device. The system reduces energy consumption. The tail gas condensation device uses low-pressure vapor of about 0.05 MPa generated by an Nm-th-stage condenser as a heating medium. Working media are water and the low-pressure vapor, and no organic phase is involved in a process, and a reaction is stable and intrinsically safe. The water in the water separation tower is purified water and concentrated water, the purified water is returned to the top of the dehydration tower, and the concentrated water is mixed with a mother liquor and then enters the dehydration tower.

Abstract: Provided are a separation tower and method for treating condensed water. In order to overcome the defects that an apparatus has high investment and energy consumption and requires high safety due to the need to use an organic phase as an extractant, the present disclosure provides a separation tower for treating condensed water. The water separation tower includes a tower body. Evaporation units for purifying the condensed water are disposed in the tower body. A final-effect condensation unit is disposed below the evaporation units and connected with a vacuum pump.

Abstract: The present invention relates to a method of recycling mother liquid of a PTA refining unit. The present invention recycles waste heat and PT acids of a PTA mother liquid to effectively utilize heat in the PTA mother liquid, solves influence of crystallization of the PT acids on subsequent system, reduces pollution to the environment, and can produce huge economic benefits by using high efficient multistage flash distillation technology, low temperature cogeneration technology, heat pump heating and cooling technology, and low temperature crystallization technology.

Abstract: The present invention relates to a method of recycling mother liquid of a PTA refining unit. The present invention recycles waste heat and PT acids of a PTA mother liquid to effectively utilize heat in the PTA mother liquid, solves influence of crystallization of the PT acids on subsequent system, reduces pollution to the environment, and can produce huge economic benefits by using high efficient multistage flash distillation technology, low temperature cogeneration technology, heat pump heating and cooling technology, and low temperature crystallization technology.