Chlorine-alkali wastewater forward osmosis treatment system and treatment process

Abstract

The invention discloses a chlorine-alkali wastewater forward osmosis treatment system which comprises a forward osmosis treatment unit; the forward osmosis treatment unit comprises a forward osmosis membrane component, a concentrated wastewater outlet of the forward osmosis membrane component is sequentially connected with an evaporation and crystallization unit and a centrifugal dewatering unit, a primary slat water storage tank is connected to an absorbing liquid inlet of the forward osmosis membrane component, and absorbing liquid provided for the forward osmosis membrane component is filled in the primary slat water storage tank. The invention further discloses a treatment process of chlorine-alkali wastewater, which comprises the following treatment steps: a, performing forward osmosis treatment on wastewater by taking a sodium chloride solution as absorbing liquid; b, performing evaporation and crystallization treatment on concentrated wastewater generated by the forward osmosis treatment; c, performing dewatering treatment on a solid phase generated by the evaporation and crystallization treatment, returning a liquid phase generated by the treatment into the step b for treatment, and recovering or discharging generated solid salt. The treatment system and the treatment process disclosed by the invention have the benefits that the process is simple, the running cost is low, and the regeneration and the zero discharge of the chlorine-alkali wastewater can be realized.

Description

Technical field [0001] The invention relates to a chlor-alkali wastewater treatment system and process, in particular to a chlor-alkali wastewater forward osmosis treatment system and treatment process using sodium chloride electrolyte as a draw liquid, and belongs to the technical field of environmental water treatment. Background technique [0002] Chlor-alkali chemical industry is a type of industry that produces sodium hydroxide, chlorine, and hydrogen from aqueous sodium chloride solution, and produces a series of chemical products using sodium hydroxide, chlorine and hydrogen as raw materials. The chlor-alkali industry needs to use a lot of water to convert salt during the production process. At the same time, a large amount of wastewater rich in salt and organic matter will be produced in the subsequent chemical process. As the country's requirements for environmental protection become higher and higher, it is of great practical significance to realize the efficient recycl...

AI Technical Summary

Problems solved by technology

[0008] However, in the current forward osmosis process, in order to consider the recovery and reuse of the draw solution, volatile substances such as ammonia that are easy to be recovered are usually used as the draw solution. On the one hand, ammonia water has a relatively strong smell, which affects the production and working environment; The advanced recovery and recycling process significantly increases the operating cost of the forward osmosis process

Moreover, if ammonium ions or organic nitrogen compounds remain in the clear water after the recovery of the drawing solution, they will be converted into highly explosive NCl by chlorine in the electrolytic cell 3 , may explode with the accumulation of chlorine gas in the liquid chlorine process

Therefore, in the forward osmosis process using ammonia water as the draw solution, the recovered clean water is not suitable for reuse in the system, and the operating cost is relatively high

Images