Concentration crystallization zero-emission system for wastewater in thermal power plant

Abstract

The invention belongs to the technical field of wastewater treatment in a thermal power plant and particularly relates to a concentration crystallization zero-emission system for wastewater in the thermal power plant. The system includes a denitrating apparatus, a main dust remover and a desulfurizing column. An air preheater is arranged on a flue between the denitrating apparatus and the main dust remover. A draft fan is arranged on a flue between the main dust remover and the desulfurizing column. The system also includes a desulfurizing wastewater spray-concentrating apparatus, which performs spray-concentration to the desulfurizing wastewater by means of heat in low-temperature flue gas in the flue between the main dust remover and the desulfurizing column, and a concentrated wastewater spray-crystallization apparatus, which performs spray-crystallization to the concentrated wastewater by means of heat in high-temperature flue gas in the flue between the denitrating apparatus and the air preheater. The system is free of consumption of extra heat during the concentration crystallization process, so that operation energy consumption is greatly reduced, and zero-emission of wastewater in thermal power plant is achieved.

Description

technical field [0001] The invention belongs to the technical field of waste water treatment in thermal power plants, and in particular relates to a zero discharge system for concentration and crystallization of waste water in thermal power plants. Background technique [0002] Limestone-gypsum wet desulfurization technology is currently the most widely used flue gas desulfurization technology in thermal power plants. During the operation of the desulfurization device, a large amount of wastewater is regularly discharged, that is, desulfurization wastewater. The wastewater has the characteristics of high concentration of suspended solids, high concentration of inorganic salts and heavy metal ions. [0003] Traditional desulfurization wastewater treatment process chemical dosing method: traditional chemical treatment methods of neutralization, precipitation, flocculation, concentration and clarification are often used for treatment. Although it can reduce the content of heav...

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Problems solved by technology

[0010] Although this evaporation method has a simple system and low investment and energy consumption, it has high requirements on the flue gas temperature and the evaporation process in the flue; if the evaporation conditions are not met, the waste water will enter the electric main dust collector in a liquid state There is a great risk of damage caused by downstream equipment. A small number of power plants in China have done pilot installations, but they have basically been shut down or dismantled now.

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