Zero-release coupling humidifying dust-removing synergizing system and method for desulfurization wastewater

Abstract

The invention relates to a zero-release coupling humidifying dust-removing synergizing system and a zero-release coupling humidifying dust-removing synergizing method for desulfurization wastewater. The zero-release coupling humidifying dust-removing synergizing system comprises a desulfurizing tower, a gypsum dewatering system, a wastewater cyclone, a wastewater box, a rotary spraying and evaporating tower and a dust remover, wherein wastewater treated through the gypsum dewatering system is treated through the wastewater cyclone; afterwards, one part underflows to the desulfurizing tower to be repeatedly utilized; one part overflows to a wastewater box to be collected; the wastewater is conveyed to a rotary sprayer to be atomized; an atomized fog drop descends, is regressively in contact with a high-temperature fume which is introduced from the front of an air pre-heater; a solid particle in the evaporated wastewater and the fume integrally descend to the lower part of a rotary evaporating tower, and enter a front flue of the dust remover through an outlet flue of the rotary evaporating tower; the wastewater passes through the dust remover in a form of purified water vapor to enter the desulfurizing tower. The zero-release coupling humidifying dust-removing synergizing system and the zero-release coupling humidifying dust-removing synergizing method are high in wastewater treatment stability, and are not influenced by the load of a unit; the investment and running expenses are low; the water consumption and the energy consumption are reduced; the fume humidity is increased while the zero release of the wastewater is realized; the dust removal efficiency of the dust remover is improved.

Description

technical field [0001] The invention belongs to the technical field of desulfurization wastewater control, and in particular relates to a desulfurization wastewater zero-discharge coupling humidity adjustment and dust removal efficiency enhancement system and method. Background technique [0002] The desulfurization wastewater is acidic with a pH between 4 and 6, and the salt content is high. For aluminum hydroxide, the hardness of the wastewater is relatively high between 5116 and 11545 mg / L. The cations in the wastewater are mainly hardness ions such as calcium and magnesium. There are many types of heavy metal ions, and the content is much higher than the discharge standard. Chloride ions are likely to cause corrosion of subsequent equipment. [0003] The "Technical Regulations for Wastewater Treatment Design of Thermal Power Plants" promulgated in 2006 has clearly stated that the desulfurization wastewater treatment facilities of thermal power plants should be set up se...

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Problems solved by technology

[0008] The desulfurization wastewater is used in the wet slag removal system after conventional treatment or without treatment. Because the desulfurization wastewater is acidic and contains high chloride ions, it will affect the comprehensive utilization of ash and slag and is extremely corrosive to metals. In addition, the slag washing water needs Secondary treatment, it is difficult to achieve true zero discharge of wastewater

[0009] Chinese patent CN 204185326U provides a zero-discharge treatment system for desulfurization wastewater, including wastewater pretreatment equipment, evaporation concentration equipment, and evaporation crystallization equipment. Through the treatment of the equipment, the final products are distilled water and crystallized salt, reducing the discharge of harmful substances. However, the evaporation and crystallization technology has requirements on the purity of the crystallized salt, and advanced pretreatment of desulfurization wastewater is required. The subsequent membrane concentration and evaporation crystallization conditions need to remove turbidity, scaling substances, and chemical oxygen demand (COD). In the concentration stage, it is easy to scale, which affects the operation and service life of the equipment. The concentration of magnesium ions in the desulfurization wastewater is high, and the softened product magnesium hydroxide is a flocculent colloid, which is difficult to precipitate and difficult to filter and separate, which brings difficulties to the process operation. , at the same time, the operating cost is relatively high, and the operating cost of evaporation and crystallization accounts for about 45% of the total operating cost

The system must discharge a small part of brine or sludge, and the product crystal salt obtained in wastewater treatment is difficult to be used commercially or needs to be treated as solid waste

[0010] Chinese patent CN 204097264U provides a zero-discharge device for desulfurization wastewater, which consists of a desulfurization system, a two-stage wastewater cyclone, an ultrasonic atomizing nozzle, a dust collector, a wastewater pump, and a wastewater delivery pump. There is no external discharge of waste water, and the inorganic salt ions and heavy metal ions in the waste water are efficiently removed, but the load is greatly affected, and the treatment capacity is insufficient; the flue gas temperature after the air preheater is low, and it may cause damage to the dust removal system with low and low temperature electric dust removal The length of the flue is shortened, and the evaporation is not complete, resulting in dust accumulation and corrosion

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