A thermal power plant desulfurization wastewater zero-discharge treatment system and method thereof

Abstract

The invention discloses a thermal power plant desulfurization wastewater zero-discharge treatment system and a method thereof, belonging to the technical field of desulfurization wastewater treatment. It mainly includes a wastewater pretreatment system, a membrane concentration system, an evaporation crystallization device, a reagent addition device, a controller, and a power supply device; the wastewater pretreatment system in the present invention is obtained by adding Ca(OH) 2 、Na 2 CO 3 Two-stage reaction and adding precipitation and clarification treatment to reduce the calcium and magnesium content in the water to achieve the purpose of softening treatment; through two-stage crystallization treatment on the concentrated solution, the crystallization effect is increased, and the primary crystallization of the concentrated solution adopts a closed-loop treatment process, that is After the concentrated solution passes through the primary crystallization plate for primary crystallization, the incompletely crystallized raffinate enters the membrane concentration system through the solenoid valve 3, and then performs primary crystallization treatment again. Through the above process, all the concentrated solution is used in the crystallization process to achieve zero concentration of the concentrated solution. emission.

Description

technical field [0001] The invention relates to the technical field of desulfurization wastewater treatment, in particular to a zero-discharge treatment system and method for desulfurization wastewater in thermal power plants. Background technique [0002] Thermal power plants produce a large amount of exhaust gas containing sulfur and nitrate in the coal burned for power generation. These exhaust gases will cause pollution and form acid rain when they are discharged into the atmosphere. These exhaust gases must be desulfurized and denitrified to achieve flue gas emissions. Wet desulfurization method is to add calcium carbonate fine powder in the desulfurization tower, and add water at the same time. Calcium carbonate and sulfur dioxide react to form calcium sulfite, which is then oxidized into calcium sulfate. At the same time, due to the high temperature of the flue gas, part of the water evaporates and is discharged with the flue gas , resulting in the continuous concentr...

AI Technical Summary

Problems solved by technology

As the supplementary primary water contains chloride ions, as the water continues to evaporate, the concentration of chloride ions in the desulfurization tower will continue to increase. As the chloride ions accumulate to a certain concentration, the crystallization of calcium sulfate will be affected, and part of the desulfurization wastewater has to be discharged to reduce the The concentration of chloride ions in the slurry; while the wastewater generated during the desulfurization and denitrification process is often rich in salt and suspended solids, and its composition is extremely complex. If it is discharged directly, it will cause serious pollution to the environment. In recent years, its zero discharge has become a hot spot in the industry.

[0003] Therefore, the treatment of desulfurization wastewater is imminent, and the existing desulfurization wastewater treatment system has the following disadvantages: 1) When pretreating desulfurization wastewater, it is not possible to add reagents in a targeted manner according to the type of harmful substances in the wastewater , the treatment effect is poor; 2) When the pretreated concentrated solution is crystallized, the incompletely crystallized concentrated raffinate cannot be recovered, and the crystallization process is carried out again, resulting in a reduction in the content of salts after crystallization and a reduction in the resource recovery rate

Images