Advanced treatment method for PTA petrochemical wastewater

Abstract

The invention discloses an advanced treatment method for PTA petrochemical wastewater, which comprises a reboiler, a steam stripping tower, a multi-effect evaporator and a condenser, and comprises the steps of pumping petrochemical wastewater into the reboiler, and indirectly exchanging heat with steam to enable the wastewater to form a steam-water mixture; enabling the steam-water mixture to enter the steam stripping tower, wherein the steam stripping tower operates under normal pressure, and after steam stripping separation, light components with the boiling point lower than that of water enter a light component collecting device to be recycled; enabling the wastewater at the bottom of the steam stripping tower to enter the multi-effect evaporator to evaporate the wastewater at the bottom of the steam stripping tower; enabling the evaporated water vapor to enters the condenser, and condensing the evaporated water vapor into liquid water for recycling; concentrating the remaining wastewater according to a proportion of 10-15 times, and storing in a buffer tank; and spraying the concentrated solution in the buffer tank into an incinerator to be incinerated, recycling heat generated by incineration, and carrying out treatment on smoke generated by incineration. Equipment adopted in the method is small in occupied area, and zero discharge of petrochemical wastewater and resource recycling of light components, industrial water and steam are completely achieved.

Description

technical field [0001] The invention relates to the field of water treatment, more specifically, it relates to a method for advanced treatment of PTA petrochemical wastewater. Background technique [0002] Purified terephthalic acid-PTA, as the main chemical raw material at present, is the main petrochemical product, which is produced by the reaction of p-xylene-PX and acetic acid-AA under the action of a catalyst. PTA is one of the main raw materials for the production of polyethylene terephthalate-PET. PET polyester fiber is commonly known as polyester fiber and is the largest variety of synthetic fiber. The biggest advantage of PET is its good wrinkle resistance and shape retention , with high strength, high modulus and low water absorption, it is widely used in civil fabrics and industrial fabrics. [0003] PTA and other petrochemical products will produce a lot of wastewater, such as PTA wastewater contains phthalic acid, p-xylene, toluic acid, phthalic acid, benzoic a...

AI Technical Summary

Problems solved by technology

[0005] Two-stage aerobic method (O / O): the primary biochemical system operates under high load, has high processing capacity, and can remove most of COD; the secondary biochemical process operates under low load, has advanced processing capacity, and can remove relatively COD is difficult to remove, but the amount of sludge after disposal is large, resulting in a large amount of solid waste and hazardous waste, and the environmental risk of secondary pollution treatment is high, and the operating cost is high

However, the treatment water does not meet the standard and the operation is unstable, which brings instability and risks to the production of the enterprise; the composition of the wastewater is complex, the concentration of CODcr is high, and the concentration of organic matter is as high as 20,000 mg / L, mainly aromatic substances, and various aromatic compounds B / Low C, TDS up to 2%, cobalt, manganese, bromine and other inorganic pollutants, high COD before the wastewater enters the biochemical, strong toxicity to biochemical bacteria; low water production after the supporting membrane treatment, concentrated water still needs supporting systems Treatment can achieve zero discharge or be discharged to the wastewater station in the park

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