Cyclone de-dusting method for desulfurization wastewater

Abstract

The invention provides a cyclone de-dusting method for desulfurization wastewater. The method comprises the following steps: adopting a wastewater hydrocyclone for treating wastewater after being treated by a gypsum dehydration system; causing part of underflow to flow to a desulfurization tower for reusing and causing the other part of underflow to overflow to a wastewater tank for collecting; conveying the wastewater to a rotary atomizer for atomizing; causing the atomized fog drop to descend and to be in reverse contact with high-temperature flue gas entering from the front side of an air pre-heater; causing the solid particle in the evaporated wastewater and the flue gas to downward flow to the lower part of a rotary evaporation tower, pass by an outlet flue of the evaporation tower and enter into a front flue of a dust collector; causing the wastewater to enter into the desulfurization tower through the dust collector in the form of purified steam. According to the invention, the wastewater treatment stability is high, the treatment is not influenced by unit load, the investment and running cost is low, the water consumption and the energy consumption are saved, the wastewater treatment is realized while the humidity of the flue gas is increased and the de-dusting efficiency of the dust collector is increased.

Description

technical field [0001] The invention belongs to the technical field of desulfurization wastewater control, and in particular relates to a cyclone dedusting method for desulfurization wastewater. 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 separately, and priority should be given to treatment and reuse, without di...

AI Technical Summary

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, difficult to achieve real wastewater

[0009] Chinese patent CN 204185326U provides a desulfurization wastewater treatment system, including wastewater pretreatment equipment, evaporation concentration equipment and evaporation crystallization equipment, through the treatment of the equipment, the final product is distilled water and crystallization salt, reducing the emission of harmful substances, but evaporation Crystallization technology has requirements on the purity of crystallized salt, which requires advanced pretreatment of desulfurization wastewater. In the subsequent membrane concentration and evaporation crystallization conditions, turbidity, scaling substances, and chemical oxygen demand (COD) need to be removed. 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. 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