Zero-discharge treatment system and method for synthetic ammonia and ethylene glycol wastewater

Abstract

The invention relates to a zero-discharge treatment system for synthetic ammonia and ethylene glycol wastewater. The system comprises a pretreatment unit, a nanofiltration unit and a crystallization unit. The pretreatment unit is used for removing heavy metal ions, silicon dioxide and hardness ions in the wastewater; and the nanofiltration unit is used for nanofiltration salt separation. On the basis of multiple design concepts that gradient treatment is carried out, pollutants are discharged out of the system as much as possible and high-salt-content concentrated water does not return, a wastewater evaporative crystallization treatment system is designed, and sodium chloride extraction is carried out on second produced water in a two-stage membrane concentration and sodium chloride hot crystallization mode; the second concentrated water is subjected to sodium sulfate extraction based on cooling concentration crystallization and melt crystallization, and sodium chloride is further extracted through cooling concentration crystallization; the physicochemical indexes of the prepared sodium chloride and sodium sulfate meet the coal chemical industry byproduct industrial standard, the water quality of produced water reaches the indexes, and the effect of zero discharge of synthetic ammonia and ethylene glycol wastewater is achieved.

Description

technical field [0001] The invention relates to the technical field of zero-discharge treatment, in particular to a system and method for zero-discharge treatment of synthetic ammonia and ethylene glycol wastewater. Background technique [0002] With the continuous development of today's society, the whole process of water treatment needs to further improve efficiency and reduce costs. The zero-discharge system is different from the previous stereotyped chemical desalination systems and non-zero-discharge water reuse systems. The design concept of the zero-discharge system is no longer based on the water production index as the main appeal, but with zero discharge as the overall appeal. The latter-stage treatment device always treats the concentrated water of the previous stage, so it needs to be considered as a whole from the beginning of the design. The requirements and difficulty of zero-discharge salt-separation crystallization of high-salt wastewater are very different...

AI Technical Summary

Problems solved by technology

The defect of this patent is that the zero emission effect cannot be achieved. The reason is that the concentrated water sent to the reverse osmosis membrane has high hardness and high carbon content without a pretreatment device, and the reverse osmosis membrane will be polluted by untreated water quality. Resulting in reduced service life and reduced performance

And also did not consider the influence of silicon oxide inside the concentrated water

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