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Zero discharge technology for desulfurization wastewater-water quality analyzer
Release time：
2025-12-01 13:43:27
Zero discharge of desulfurization wastewaterTechnology-Water Quality Analyzers
Zero discharge of desulfurization wastewaterIt means that after power plant wastewater needs to be processed, the salts and pollutants in the wastewater are separated and cultured, and then discharged into the power plant enterprise in the form of a solid structure for analysis and processing or recycling, and the generated fresh water is reused to achieve no wastewater. exhaust technology. In 2017, the country promulgated the "Guidelines on Feasible Technologies for Pollution Prevention and Control in Thermal Power Plants" (HJ 2301-2017), which pointed out that the key technology for achieving near-zero discharge of wastewater from thermal power plants is to achieve zero discharge of desulfurization wastewater. Therefore, the development of low-cost zero-discharge desulfurization wastewater technology is of great research significance.
The quality of desulfurization wastewater is weakly acidic, with high SS content, excessive COD, high salt content, high hardness, and high Cl-, heavy metal ions and fluoride content. The water quantity and quality of desulfurization wastewater from different power plants fluctuate greatly. A kind of wastewater with complex water quality and difficult to treat. According to the characteristics of desulfurization wastewater, separate desulfurization wastewater treatment facilities should be set up. The discharge treatment process of enterprises that meet the standard under conventional management is the "three-box" treatment process of "neutralization + sedimentation + flocculation and clarification". In order to further realize water recycling, the "pretreatment + concentration reduction + crystallization and solidification" process route is adopted to achieveZero discharge of desulfurization wastewater, ultimately achieving the purpose of water-salt separation and freshwater reuse.
Crystal solidification technology
After pretreatment and concentration reduction treatment, most of the SS and heavy metal ions are removed. However, soluble salts such as chloride ions cannot be removed.
At present, the development of commonly used crystallization and solidification treatment technologies in my country mainly includes evaporation crystallization and flue evaporation. Evaporative crystallization is to evaporate the solution by heating, and evaporate different solvents from the solution to form a saturated solution. Then the evaporation is further increased, and the excess solute is precipitated in the form of crystals to achieve the separation of brine. Evaporation crystallization mainly includes MSF, MED and MVR technologies. Relevant content has been introduced in the chapter on heat-focused weight loss. By increasing the action or stages of the system, crystallization and separation of salts in wastewater can be achieved.
Flue evaporation uses the residual heat of the flue gas in the horizontal flue to completely evaporate the atomized wastewater, converting the pollutants in the wastewater into a solid material crystal or salt, which is eventually captured by the dust collector and removed from the flue to achieve desulfurization. Zero discharge of desulfurization wastewater. Flue evaporation is divided into main flue evaporation and bypass flue evaporation. Flue evaporation is mainly to spray atomized desulfurization wastewater into the air and analyze the direction of the flue between the preheater and dust collector for evaporation; bypass flue evaporation is to add a bypass flue evaporator to evaporate by the air preheater. A small amount of previously high-temperature treated flue gas is introduced into a bypass flue evaporator to evaporate the atomized desulfurization wastewater, and then is discharged into the flue in front of the dust collector based on crystallized salts. The crystallized salts formed after the wastewater evaporates through the flue are captured by the electrostatic precipitator and then discharged together with the fly ash.
Evaporation crystallization technology is relatively mature and widely used in power plants. It can be used in conjunction with membrane concentration technology to achieve secondary industrial salt recovery. However, the investment and operation costs are high, the area is large, and the water quality requirements are high. The development of flue gas evaporation technology has the advantages of simple information system, low investment and operation and management costs, small footprint, and low requirements for incoming water quality standards. The evaporation speed is fast and has little impact on the main flue of the boiler. However, due to the use of high-grade high-temperature flue gas, the impact on boiler efficiency should be considered.
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