System and method for comprehensive treatment of wastewater of thermal power plant and recovery of chemical resources

Abstract

The invention discloses a system and a method for comprehensive treatment of wastewater of a thermal power plant and recovery of chemical resources. The system comprises a conventional desulfurization wastewater treatment system water outlet pipeline, a regenerated high-salinity wastewater pipeline, an ammonia area wastewater pipeline, a first sodium hydroxide dosing device, a phosphate dosing device, a crystallizing reactor, a second sodium hydroxide dosing device, a coagulant dosing device, a reaction tank, a first settling tank, a carbon dioxide absorbing tower, a desulfurizing tower rear flue gas bypass and a chimney. With the adoption of the system and the method, comprehensive treatment can be effectively performed on the high-ammonia-nitrogen and high-hardness wastewater produced by the thermal power plant, operation is simple, the cost is lower, and the effluent quality is good.

Description

technical field [0001] The invention relates to a recovery system and method, in particular to a system and method for comprehensive treatment of thermal power plant waste water and recovery of chemical resources. Background technique [0002] Ammonia nitrogen is the main pollutant in water bodies. A high content of ammonia nitrogen will cause eutrophication of surface water, which is mainly manifested in the proliferation of aquatic plants, blue-green algae and other organisms, excessive consumption of dissolved oxygen in water, seriously affecting water quality, and causing aquatic organisms such as fish to be deficient. Oxygen death, therefore, in order to protect the ecological environment and reduce water pollution, the country requires ammonia nitrogen-containing wastewater to meet the first-level standard of the "Comprehensive Wastewater Discharge Standard" (GB8978-1996, ρ(NH 3 -N)≤15mg / L) before it can be discharged. The common high-ammonia-nitrogen wastewater in th...

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Problems solved by technology

The commonly used chemical softening method is to add chemical agents such as calcium hydroxide, sodium hydroxide, and sodium carbonate to make calcium and magnesium form mixed sediments such as calcium sulfate, calcium carbonate, and magnesium hydroxide, which are discharged from the power plant in the form of waste chemical sludge. The cost of chemical agents added is high, and the operating cost of the treatment system is high

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