System and method for treating high salinity wastewater

Abstract

The invention discloses a treatment system and evaporating treatment method for high salinity wastewater. The treatment system comprises a desulfurization waste water conventional treatment device, a high-salinity water concentration device, a concentrated high-salinity water storage pool and an atomizer which are connected in sequence. The treatment system further comprises a high-salinity water boiling point reducing device which is arranged at any appropriate position in front of the concentrated high-salinity water storage pool. The water spraying amount of concentrated high-salinity water sprayed out of the atomizer can be adjusted. The treatment method comprises the steps that 1, after desulfurization waste water is subjected to conventional treatment, upper-layer clear water, namely, high-salinity water is collected, the high-salinity water is concentrated to be reduced, and concentrated high-salinity water is formed and stored in the concentrated high-salinity water storage pool; 2, the concentrated high-salinity water in the concentrated high-salinity water storage pool is sprayed into a flue between a hearth and a dust remover and / or the hearth through the atomizer and subjected to atomization and evaporation, and crystal substances are mixed into coal ash to be removed together, wherein the water spray amount of the concentrated high-salinity water sprayed into the flue between the hearth and the dust remover and / or the hearth is adjusted according to flue gas temperature.

Description

technical field [0001] The invention relates to a treatment system and method for high-salt waste water, in particular to a treatment system and method for high-salt desulfurization waste water produced in coal-fired boiler flue gas treatment. Background technique [0002] With the improvement of water saving awareness and environmental protection awareness in our country, many manufacturers operating coal-fired boilers require the design of "zero discharge" of wastewater in the whole plant. In order to meet the normal operation of the desulfurization system and the material balance in the system, desulfurization wastewater needs to be discharged. Desulfurization wastewater has high salt content, high corrosion, and easy scaling. At present, this kind of desulfurization wastewater is generally treated by triple box in China, which only removes heavy metals and suspended solids in the wastewater, but cannot remove high-concentration chloride ions. The treated waste liquid is...

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Problems solved by technology

Such as patents: CN104689676A (wet desulfurization wastewater utilization system and its process), CN104030512A (a system and method for treating terminal wastewater by using flue gas waste heat), CN104129824A (comprehensive treatment of desulfurization wastewater in thermal power plants and dust particle emission reduction method), CN104030512A (a kind of 300MW and above thermal power generating unit desulfurization waste water treatment device) etc., but the actual operation effect of above-mentioned design is all not good, for many years, the experiment that high-salt desulfurization waste water is sprayed into the flue before the precipitator is constantly trying, but So far, there is no successful case of zero discharge of desulfurization wastewater

[0006] Although the flue evaporation method has low initial investment and low operating cost, the following problems often occur in actual operation: pipeline corrosion; In the flue, the electrode line of the dust collector and the ash conveying device

[0007] Whether the liquid droplets can completely evaporate in the flue mainly depends on the following four factors: (1) residence time, usually the length of the horizontal flue in front of the dust collector is about 10-20 meters, and the flue gas stays at this position for about one second ; (2) The particle size of the droplet, the evaporation time of the droplet is positively correlated with the square of the particle size, if the particle size is too large, it cannot be completely evaporated in the flue of the dust collector, and the particle size of the atomized droplet is basically in a normal distribution. Among them, although the number of droplets with the largest particle size is small, the evaporation time is the longest, which is the main factor leading to the fouling and blockage of the flue. The existing flue evaporation technology prefers dual-fluid nozzles to ensure that the maximum particle size of the droplets does not exceed 100 microns; (3) The difference between the flue gas temperature and the boiling point of high-salt desulfurization wastewater, the droplet evaporation time is negatively correlated with this temperature difference, the larger the temperature difference, the faster the droplet evaporates; (4) The amount of water sprayed, for each two-fluid For nozzles, the larger the water volume, the larger the maximum particle size of the corresponding droplets, and the smaller the water volume, the smaller the maximum particle size of the corresponding droplets. In addition, the evaporation of water in the flue will reduce the smoke temperature. For the same particle size droplets, the smoke temperature will drop. The larger the magnitude, the longer it takes to evaporate

[0008] Restricted by the above conditions, the existing flue evaporation technology cannot guarantee all the desulfurization wastewater generated by evaporation under various flue gas conditions. It seems that the cost is low, but in most cases it can only achieve the reduction of desulfurization wastewater discharge. Difficult to ensure zero discharge, and poor safety, the greater the amount of water sprayed, the greater the threat of fouling and clogging of the flue and dust collector

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