System and method for treating desulfurization wastewater by utilizing flue gas waste heat

Abstract

The invention belongs to the technical field of wastewater treatment, and particularly relates to a system and a method for treating desulfurization wastewater by utilizing flue gas waste heat. The desulfurization wastewater treatment system is characterized by comprising a boiler, an air preheater, an electrostatic dust collector, an induced draft fan, and a concentration system, a desulfurization tower and a chimney which are arranged in parallel; all the mentioned units are sequentially connected through a flue; a liquid outlet in the bottom of the concentration system is connected with a spraying device in the drying bed, a flue in front of the air preheater is communicated with an inlet of the drying bed, and an outlet of the drying bed is communicated with the flue. The problems thatin the prior art, scaling is likely to be caused by direct spraying in a flue, and production and operation are seriously affected are solved, wherein low-grade heat source evaporation and concentration of salt-containing wastewater can be achieved, so that the investment and operation cost is low, energy conservation and consumption reduction of enterprises are promoted, and meanwhile the wastewater treatment cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a system and method for treating desulfurization wastewater by using waste heat of flue gas. Background technique [0002] At present, the processes commonly used to treat desulfurization wastewater include pretreatment→membrane concentration→evaporation crystallization process. Desulfurization wastewater needs to be pretreated before membrane permeation to remove heavy metals and scaling ions, and a large amount of chemicals need to be added, which not only causes secondary pollution, but also is expensive; the membrane concentration process is prone to concentration polarization, and the permeable membrane is easily blocked by pollution The pores of the membrane lead to a significant reduction in the water treatment capacity and treatment efficiency of the permeable membrane. In addition, the cleaning process of the permeable membrane is cumbersome and...

AI Technical Summary

Problems solved by technology

Desulfurization wastewater needs to be pretreated before membrane permeation to remove heavy metals and scaling ions, and a large amount of chemicals need to be added, which not only causes secondary pollution, but also is expensive; the membrane concentration process is prone to concentration polarization, and the permeable membrane is easily blocked by pollution The pores of the membrane lead to a significant reduction in the water treatment capacity and treatment efficiency of the permeable membrane

In addition, the cleaning process of the osmotic membrane is cumbersome and has high requirements on the quality of desulfurization wastewater; the evaporation and crystallization process consumes a lot of energy, is easy to form crystal scale, and has a high operating cost, which restricts the development of the process

[0003] After preliminary treatment, the desulfurization wastewater is still in a state of high chloride and high salt content, and it is impossible to achieve true zero discharge, and its reuse is very limited

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