Low-energy-consumption desulfurization wastewater zero emission technology and device

Abstract

The invention discloses a low-energy-consumption desulfurization wastewater zero emission technology and device. The technology comprises the following steps: (1) conveying desulfurization wastewaterinto an adjusting tank and adjusting the pH (Potential of Hydrogen) value; (2) then conveying the desulfurization wastewater into a sedimentation tank; adjusting the pH of the wastewater to be 10 to 13; after carrying out sedimentation, conveying supernatant into a denitrification tower; conveying bottom sludge into a sludge treatment unit; (3) removing ammonia nitrogen pollutants in the wastewater in the denitrification tower through a blowing-off technology; (4) conveying the blown-off wastewater into a primary reverse osmosis membrane device to obtain primary freshwater for direct recycling; conveying concentrated water into an electric ion membrane device; (5) conveying the concentrated water into the electric ion membrane device and separating to obtain concentrated water and freshwater; conveying the concentrated water into an evaporation curing and crystallization system for separating and crystallizing and conveying the freshwater into a secondary reverse osmosis membrane. According to the low-energy-consumption desulfurization wastewater zero emission technology and device, disclosed by the invention, the pre-treatment problems of slightly high operation pressure and largeenergy consumption in a desulfurization wastewater membrane treatment technology are solved; heavy metal and suspended matters are removed and the ammonia nitrogen pollutants also can be removed; furthermore, the quality of recycled water is improved, and the aims of improving the wastewater recycling rate and reducing the wastewater emission are realized.

Description

technical field [0001] The invention relates to a zero-discharge process and device for low-energy desulfurization wastewater, belonging to the field of resources and environmental protection. Background technique [0002] In order to meet the increasingly stringent environmental protection requirements in recent years, most thermal power plants are equipped with flue gas desulfurization and denitrification devices to control the emission of sulfur dioxide and nitrogen oxides. During the flue gas desulfurization process, some pollutants in the flue gas, such as metals, salts, chloride ions, etc., will be absorbed by the desulfurization slurry, and the ammonia escaped during the denitrification process will also enter the desulfurization slurry to form ammonia nitrogen pollutants. With the continuous circulation of the desulfurization slurry, these pollutants are continuously enriched, which will affect the quality of desulfurization gypsum, and will also intensify the corros...

AI Technical Summary

Problems solved by technology

However, the operating pressure of the reverse osmosis membrane used in this process is relatively high. The operating pressure of the roll-type reverse osmosis membrane is 1-6 MPa, and the operating pressure of the high-pressure flat membrane is as high as 8-16 MPa, which leads to an increase in energy consumption of the membrane treatment process.

Patent CN200910233204 has invented a desulfurization wastewater treatment system combined with pretreatment + nanofiltration membrane + reverse osmosis membrane. The operating pressure of the nanofiltration membrane in this process is 0.5-4.0 MPa, and the operating pressure of the reverse osmosis membrane is 0.5-8.0 MPa. Although The operating pressure is lower than the process in the patent CN201710207899, but still high

In addition, neither of the processes invented by these two patents is aimed at treating ammonia nitrogen pollutants in wastewater

In the future, the discharge standards of desulfurization wastewater will become more and more stringent. The current treatment process may no longer meet the environmental protection requirements and needs to be further optimized.

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