阅读说明：本技术 一种利用烟气热量的脱硫废水处理系统和处理方法 (Desulfurization wastewater treatment system and method utilizing flue gas heat ) 是由 胡相余 王健 荆黎 阮柏松 秦福初 葛智泉 李建 叶明君 于 2021-07-13 设计创作，主要内容包括：本发明公开了一种利用烟气热量的脱硫废水处理系统和处理方法,所述系统包括脱硝装置、空预器、除尘器、主烟道浓缩装置、湿法脱硫吸收塔、预沉池和蒸发塔；脱硝装置、空预器、除尘器、主烟道浓缩装置和湿法脱硫吸收塔依次通过烟气管道连通；湿法脱硫吸收塔的出水口连通预沉池,预沉池的出水口连通主烟道浓缩装置的入水口；主烟道浓缩装置的出水口连通蒸发塔的入水口；蒸发塔的入风口连通于脱硝装置和空预器之间的烟气管道上；蒸发塔的出风口连通于空预器和除尘器之间的烟气管道上。本发明能够降低处理脱硫废水的成本。(The invention discloses a desulfurization wastewater treatment system and a desulfurization wastewater treatment method by utilizing flue gas heat, wherein the system comprises a denitration device, an air preheater, a dust remover, a main flue concentration device, a wet desulfurization absorption tower, a pre-settling tank and an evaporation tower; the denitration device, the air preheater, the dust remover, the main flue concentration device and the wet desulphurization absorption tower are sequentially communicated through a flue gas pipeline; the water outlet of the wet desulphurization absorption tower is communicated with a pre-settling tank, and the water outlet of the pre-settling tank is communicated with the water inlet of the main flue concentration device; the water outlet of the main flue concentration device is communicated with the water inlet of the evaporation tower; an air inlet of the evaporation tower is communicated with a flue gas pipeline between the denitration device and the air preheater; the air outlet of the evaporation tower is communicated with a flue gas pipeline between the air preheater and the dust remover. The invention can reduce the cost of treating the desulfurization wastewater.)

1. A desulfurization wastewater treatment system utilizing flue gas heat is characterized by comprising a denitration device, an air preheater, a dust remover, a main flue concentration device, a wet desulfurization absorption tower, a pre-settling tank and an evaporation tower;

the denitration device, the air preheater, the dust remover, the main flue concentration device and the wet desulphurization absorption tower are sequentially communicated through a flue gas pipeline;

the water outlet of the wet desulphurization absorption tower is communicated with a pre-settling tank, and the water outlet of the pre-settling tank is communicated with the water inlet of the main flue concentration device; the water outlet of the main flue concentration device is communicated with the water inlet of the evaporation tower; an air inlet of the evaporation tower is communicated with a flue gas pipeline between the denitration device and the air preheater; the air outlet of the evaporation tower is communicated with a flue gas pipeline between the air preheater and the dust remover.

2. The desulfurization wastewater treatment system using heat of flue gas according to claim 1, wherein the water inlet of the main flue concentration device is disposed at the top of the main flue concentration device, the air inlet and the air outlet are disposed at the side of the main flue concentration device, and the water outlet is disposed at the lower part of the main flue concentration device.

3. The desulfurization wastewater treatment system utilizing heat of flue gas as recited in claim 1, wherein the air inlet and the water inlet of the evaporation tower are both disposed at the top of the evaporation tower, and the air outlet of the evaporation tower is disposed at the bottom of the evaporation tower.

4. The desulfurization wastewater treatment system utilizing heat of flue gas according to any one of claims 1 to 3, further comprising a coagulation sedimentation device, wherein a water inlet of the coagulation sedimentation device is communicated with a water outlet of the main flue concentration device, and a water outlet of the coagulation sedimentation device is communicated with a water inlet of the evaporation tower.

5. The desulfurization wastewater treatment system utilizing heat of flue gas as recited in claim 4, wherein an atomizer is further disposed between the water outlet of said coagulation sedimentation device and the water inlet of said evaporation tower.

6. The desulfurization wastewater treatment system utilizing heat of flue gas as recited in claim 5, wherein said atomizer is a two-fluid atomization spray gun, said two-fluid atomization spray gun comprises an air compressor and a spray water pump, said spray water pump is communicated with the water outlet of the coagulation sedimentation device and the water inlet of the evaporation tower, and said air compressor is communicated with the spray water pump.

7. The desulfurization waste water treatment system utilizing heat of flue gas as set forth in any one of claims 1 to 3, further comprising a chimney communicating with the wet desulfurization absorption tower through a flue gas duct.

8. A desulfurization wastewater treatment method using heat of flue gas, comprising the steps of:

collecting desulfurization wastewater in the wet desulfurization absorption tower;

concentrating the desulfurization wastewater by using the flue gas in the flue gas pipeline;

and drying the concentrated desulfurization wastewater by using the flue gas in the flue gas pipeline to obtain a crystalline solid.

9. The method of claim 8, further comprising the steps of:

discharging the flue gas after concentrating the desulfurization wastewater into a wet desulfurization absorption tower for desulfurization;

and (4) discharging the flue gas subjected to desulfurization wastewater evaporation into a dust remover and a wet desulfurization absorption tower in sequence for dust removal and desulfurization.

Technical Field

The invention relates to the technical field of industrial wastewater treatment, in particular to a concentration treatment system and a treatment method for zero discharge of desulfurization wastewater.

Background

SO₂Is one of the main atmospheric pollutants faced by human beings at present, SO in air₂Too high a content may cause acid rain, damaging crops and buildings. SO (SO)₂It can also be adsorbed on dust in the air and enter human body through respiratory tract, which seriously damages human health. And most of SO₂The emissions of (b) are derived from coal combustion, for example: in a thermal power plant, industrial coal, heating and the like, a large amount of SO is generated in the process of burning the coal₂。

In order to reduce SO in the process of burning coal₂The emission of (2) and the flue gas desulfurization are treatment modes widely adopted at present. For example: in coal-fired power plants, limestone/gypsum wet flue gas desulfurization processes are commonly used to desulfurize flue gas. However, the wet desulfurization process generates a large amount of desulfurization wastewater containing suspended solids and heavy metal ions, and having high hardness and high pollution.

Currently, to realize zero discharge of desulfurization waste water, the method generally adopts the method comprising: chemical pretreatment, concentration and decrement, and concentrated water end treatment. In the related technology, the chemical cost of the chemical pretreatment stage is high, and the energy consumption cost for evaporation and crystallization in the concentration reduction and concentrated water end treatment is high, so that the operation cost of the desulfurization wastewater zero-discharge system is high.

Therefore, the operation cost of the desulfurization wastewater zero-discharge system in the related art is high.

Disclosure of Invention

The invention provides a wastewater concentration treatment system and a wastewater concentration treatment method aiming at a desulfurization wastewater zero-discharge process, and aims to solve the problem of high operation cost of a desulfurization wastewater zero-discharge system in the related art.

In order to solve the technical problems, the invention adopts the following technical scheme:

a desulfurization wastewater treatment system utilizing flue gas heat comprises a denitration device, an air preheater, a dust remover, a main flue concentration device, a wet desulfurization absorption tower, a pre-settling tank and an evaporation tower;

the denitration device, the air preheater, the dust remover, the main flue concentration device and the wet desulphurization absorption tower are sequentially communicated through a flue gas pipeline;

the water outlet of the wet desulphurization absorption tower is communicated with a pre-settling tank, and the water outlet of the pre-settling tank is communicated with the water inlet of the main flue concentration device; the water outlet of the main flue concentration device is communicated with the water inlet of the evaporation tower; an air inlet of the evaporation tower is communicated with a flue gas pipeline between the denitration device and the air preheater; the air outlet of the evaporation tower is communicated with a flue gas pipeline between the air preheater and the dust remover.

Preferably, the water inlet of the main flue concentration device is arranged at the top of the main flue concentration device, the air inlet and the air outlet are arranged at the side part of the main flue concentration device, and the water outlet is arranged at the lower part of the main flue concentration device.

Preferably, the air inlet and the water inlet of the evaporation tower are both arranged at the top of the evaporation tower, and the air outlet of the evaporation tower is arranged at the bottom of the evaporation tower.

Preferably, the system further comprises a coagulating sedimentation device, wherein a water inlet of the coagulating sedimentation device is communicated with a water outlet of the main flue concentration device, and a water outlet of the coagulating sedimentation device is communicated with a water inlet of the evaporation tower.

Further preferably, an atomizer is further arranged between the water outlet of the coagulating sedimentation device and the water inlet of the evaporation tower.

Still further preferably, the atomizer is a two-fluid atomization spray gun, the two-fluid atomization spray gun comprises an air compressor and a spray water pump, the spray water pump is communicated with a water outlet of the coagulation sedimentation device and a water inlet of the evaporation tower, and the air compressor is communicated with the spray water pump.

Preferably, the system further comprises a chimney, and the chimney is communicated with the wet desulphurization absorption tower through a flue gas pipeline.

A desulfurization wastewater treatment method using heat of flue gas, comprising the steps of:

collecting desulfurization wastewater in the wet desulfurization absorption tower;

concentrating the desulfurization wastewater by using the flue gas in the flue gas pipeline;

and drying the concentrated desulfurization wastewater by using the flue gas in the flue gas pipeline to obtain a crystalline solid.

Further, the method further comprises the steps of:

discharging the flue gas after concentrating the desulfurization wastewater into a wet desulfurization absorption tower for desulfurization;

and (4) discharging the flue gas subjected to desulfurization wastewater evaporation into a dust remover and a wet desulfurization absorption tower in sequence for dust removal and desulfurization.

The invention provides a desulfurization wastewater treatment system, which is applied to a coal-fired power plant, wherein flue gas generated by the coal-fired power plant is discharged to the outside after being sequentially introduced into a denitration device, an air preheater, a dust remover and a wet desulfurization absorption tower through a flue gas pipeline, and the temperature of the flue gas in the pipeline before the air preheater is higher than that of the flue gas in the pipeline after the air preheater, wherein the system comprises:

the pre-settling tank is communicated with a water outlet of the wet desulphurization absorption tower and is used for collecting the desulphurization wastewater in the wet desulphurization absorption tower;

the main flue concentration device replaces part of the flue, a water inlet of the main flue concentration device is communicated with a water outlet of the pre-sedimentation tank, and an air inlet of the main flue concentration device is communicated with a flue gas pipeline behind the dust remover and used for concentrating the desulfurization wastewater by utilizing flue gas in the pipeline;

and the water inlet of the evaporation tower is communicated with the water outlet of the main flue concentration device, and the air inlet of the evaporation tower is communicated with a flue gas pipeline between the denitration device and the air preheater and used for evaporating, drying and concentrating the desulfurization wastewater by utilizing the flue gas in the pipeline.

Preferably, the concentration device is formed by rebuilding a main flue of an original power plant, a concentration tower does not need to be additionally built, a foundation is built without soil, a booster fan does not exist, and the concentration device can also be newly built.

Preferably, a coagulating sedimentation device is communicated between the water outlet of the main flue concentration device and the water inlet of the evaporation tower, and is used for clarifying and separating the concentrated desulfurization wastewater into clarified liquid and precipitate through the coagulating sedimentation device so as to discharge the clarified liquid into the evaporation tower.

Preferably, an atomizer is further arranged between the water outlet of the coagulating sedimentation device and the water inlet of the evaporation tower, and is used for discharging the clear liquid discharged by the coagulating sedimentation device into the evaporation tower after being atomized.

Preferably, the atomizer is a two-fluid atomization spray gun, the two-fluid atomization spray gun comprises an air compressor and a spray water pump, the air compressor atomizes the clear liquid sprayed by the spray water pump into water mist with the particle size of 20-200 μm, the spray water pump is communicated with a water outlet of the coagulation and precipitation device and a water inlet of the evaporation tower, and the water outlet of the two-fluid atomization spray gun is arranged at the water inlet of the evaporation tower.

Compared with the prior art, the invention has the beneficial effects that:

in the invention, the flue gas discharged by the coal-fired power plant is used for concentrating the desulfurization wastewater in the concentration device, and the concentrated desulfurization wastewater is evaporated in the evaporation tower, so that the zero discharge of the desulfurization wastewater is realized. Compared with the traditional concentration device for the waste heat of the flue gas, the device omits a booster fan and saves a large amount of electricity charge; compared with other membrane concentration technologies, chemical pretreatment of the desulfurization wastewater is omitted, so that the chemical pretreatment agent cost is saved, the desulfurization wastewater is dried twice by using the energy discharged by a coal-fired power plant, and energy is not required to be provided for drying the desulfurization wastewater, so that the energy consumption for treating the desulfurization wastewater is reduced, and therefore, the desulfurization wastewater treatment system provided by the invention can reduce the cost for treating the desulfurization wastewater.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed for the embodiment or the prior art description will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic view showing the construction of a desulfurization waste water treatment system of the present invention;

FIG. 2 is a flow chart of the desulfurization waste water treatment method of the present invention;

FIG. 3 is a flow chart of the desulfurization waste water treatment method of the present invention.

Reference numerals: 12. a denitration device; 13. an air preheater; 14. a dust remover; 15. a main flue concentration device; 16. a wet desulfurization absorption tower; 17. a chimney; 21. a preliminary sedimentation tank; 22. a coagulating sedimentation device; 23. an evaporation tower; 301-305 are steps of the method.

Detailed Description

The technical solutions in the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

As shown in figure 1, flue gas generated by a coal-fired power plant is sequentially introduced into a denitration device 12, an air preheater 13, a dust remover 14, a main flue concentration device 15, a wet desulfurization tower 16 and a chimney 17 through a flue gas pipeline and then discharged to the outside, and the temperature of the flue gas in the flue gas pipeline before the air preheater 13 is higher than that of the flue gas in the flue gas after the air preheater 13.

As shown in fig. 1, the desulfurization waste water treatment system comprises:

the pre-settling tank 21 is communicated with a water outlet of the wet desulphurization absorption tower 16 and is used for collecting desulphurization wastewater in the wet desulphurization absorption tower 16;

a main flue concentration device 15, wherein a water inlet of the main flue concentration device 15 is communicated with a water outlet of the pre-sedimentation tank 21, and an air inlet of the main flue concentration device 15 is communicated with a flue gas pipeline behind the dust remover and is used for concentrating the desulfurization wastewater by utilizing flue gas in the pipeline;

and the water inlet of the evaporation tower 23 is communicated with the water outlet of the main flue concentration device 15, and the air inlet of the evaporation tower 23 is communicated with a flue gas pipeline between the denitration device and the air preheater and used for evaporating, drying and concentrating the desulfurization wastewater by utilizing the flue gas in the pipeline.

Wherein, the boiler of the coal-fired power plant carries out coal-fired reaction, thereby generating flue gas with high temperature, and the flue gas is mixed with dust and sulfur dioxide SO₂Oxynitride (e.g. NO)₂) In order to avoid the environmental pollution caused by the flue gas, the flue gas is required to comprise: and the waste gas can be discharged into the atmosphere after the treatment including denitration, temperature reduction, dust removal and desulfurization.

In addition, before the temperature reduction, the temperature of the flue gas discharged by the coal-fired power plant is very high, such as: between 150 ℃ and 220 ℃, which can be called high temperature flue gas. After the temperature reduction, the flue gas still has high residual heat, such as: between 90 ℃ and 110 ℃, which can be called low temperature flue gas.

And, can concentrate 60 ~ 80% with desulfurization waste water through flue main concentration device 15, greatly reduced the volume that gets into the desulfurization waste water in the evaporation tower 23.

Therefore, the low-temperature flue gas is firstly utilized to concentrate the desulfurization wastewater so as to reduce the water content of the desulfurization wastewater and reduce the volume of the desulfurization wastewater. And the concentrated desulfurization wastewater is completely evaporated by using high-temperature flue gas, so that zero discharge of the wastewater is achieved. The utilization rate of high-temperature flue gas can be reduced, so that the reduction of the heat efficiency of the boiler is avoided.

As shown in fig. 1, the coal-fired power plant is further provided with a chimney 17, and the wet desulfurization absorption tower 16 is communicated with the chimney 17 so as to discharge flue gas subjected to denitration, temperature reduction, dust removal, desulfurization and the like to the atmosphere.

The denitration device 12 may be a selective catalytic reduction denitration device (SCR), but may be any of a flue gas recirculation denitration device, a selective non-catalytic reduction denitration device (SNCR), and the like.

The water consumption of the wet desulfurization absorption tower 16, i.e., the process make-up water consumption, needs to be supplemented to ensure the efficiency of wet desulfurization in the wet desulfurization absorption tower 16. The air outlet of the main flue concentration device 15 and the air outlet of the evaporation tower 23 are both communicated with a flue gas pipeline, so that water vapor formed by evaporation in the concentration device 15 and the evaporation tower 23 enters the wet desulphurization absorption tower 16 through the flue gas pipeline to supplement the water amount in the wet desulphurization absorption tower 16.

Therefore, the water in the desulfurization wastewater can be recycled, and the aim of reducing the supplementary water amount in the wet desulfurization absorption tower is achieved.

In this embodiment, the flue gas after utilizing the dust removal is concentrated desulfurization waste water, avoids in the dust in the flue gas gets into desulfurization waste water, causes to carry out repeated dust removal to the dust to can promote desulfurization waste water's treatment effeciency.

In addition, as shown in fig. 1, the air outlet of the evaporation tower 23 communicates with a pipe between the air preheater and the dust remover.

Since the desulfurization waste water is completely evaporated in the evaporation tower 23, the residual crystals after drying the desulfurization waste water are blown into the dust collector 14 by blowing the flue gas, so as to remove dust.

In this embodiment, can utilize the dust remover to collect the crystallization of desulfurization waste water, avoid the crystallization of desulfurization waste water to discharge to the external world and cause environmental pollution.

In addition, residual crystals after the desulfurization wastewater is dried enter the fly ash after being dedusted by the deduster, and the amount of miscellaneous salts in the crystals is small, so that the comprehensive utilization of the fly ash is not influenced, and the problem of disposal of miscellaneous salts is avoided, thereby facilitating the cyclic utilization of the fly ash.

The water inlet of the concentration device 15 is arranged at the top of the concentration device 15, the air inlet is arranged at the side part of the concentration device 15, the water outlet of the concentrated water is arranged at the lower part of the concentration device 15, and the air outlet is arranged at the other side part of the concentration device 15. Therefore, the lateral heat exchange between the desulfurization waste water and the flue gas can be realized.

The air inlet and the water inlet of the evaporation tower 23 are both arranged at the top of the evaporation tower 23, and the air outlet of the evaporation tower 23 is arranged at the bottom of the evaporation tower 23.

Therefore, the flue gas in the evaporation tower and the desulfurization wastewater can move along the same direction, the flue gas dries the desulfurization wastewater into crystals, the crystals are blown out from the air outlet of the evaporation tower and enter the dust remover together for dust removal, the crystals of the desulfurization wastewater are prevented from being discharged into the atmosphere, the crystals of the desulfurization wastewater are collected conveniently, and the environmental protection performance of the desulfurization wastewater treatment system is improved.

A coagulating sedimentation device 22 is communicated between the water outlet of the concentration device 15 and the water inlet of the evaporation tower 23, and is used for clarifying and separating the concentrated desulfurization wastewater into clear liquid and precipitate through the coagulating sedimentation device 22 so as to discharge the clear liquid into the evaporation tower 23.

An atomizer is further arranged between the water outlet of the coagulating sedimentation device and the water inlet of the evaporation tower and used for atomizing the clear liquid discharged by the coagulating sedimentation device and then discharging the atomized clear liquid into the evaporation tower.

The atomizer is a two-fluid atomization spray gun, the two-fluid atomization spray gun comprises an air compressor and a spray water pump, the air compressor atomizes the clear liquid sprayed by the spray water pump into water mist with the particle size of 20-200 mu m, the spray water pump is communicated with a water outlet of the coagulating sedimentation device and a water inlet of the evaporation tower, and a water outlet of the two-fluid atomization spray gun is arranged at the water inlet of the evaporation tower.

Like this, can reduce the impurity that gets into in the desulfurization waste water of evaporating tower, alleviate impurity recovery's work burden to reduce the impurity content who discharges to in the external flue gas, promote desulfurization waste water treatment system's feature of environmental protection.

In the invention, the flue gas discharged by the coal-fired power plant is used for concentrating the desulfurization wastewater in the concentration device, and the concentrated desulfurization wastewater is evaporated in the evaporation tower, so that the zero discharge of the desulfurization wastewater is realized. Compared with the traditional concentration device for the waste heat of the flue gas, the device omits a booster fan and saves a large amount of electricity charge; compared with other membrane concentration technologies, chemical pretreatment of the desulfurization wastewater is omitted, so that the chemical pretreatment agent cost is saved, the desulfurization wastewater is dried twice by using the energy discharged by a coal-fired power plant, and energy is not required to be provided for drying the desulfurization wastewater, so that the energy consumption for treating the desulfurization wastewater is reduced, and therefore, the desulfurization wastewater treatment system provided by the invention can reduce the cost for treating the desulfurization wastewater.

FIG. 2 shows a flow chart of a desulfurization waste water treatment method. The method is applied to a coal-fired power plant, smoke generated by the coal-fired power plant is sequentially introduced into a denitration device, an air preheater, a dust remover and a wet desulphurization absorption tower through a smoke pipeline and then is discharged to the outside, the smoke temperature in the pipeline before the air preheater is higher than the smoke temperature in the pipeline after the air preheater, and the method comprises the following steps:

and 301, collecting the desulfurization wastewater in the wet desulfurization absorption tower.

And 302, concentrating the desulfurization wastewater by using the flue gas in the second side pipeline.

Step 303, drying the concentrated desulfurization wastewater by using the flue gas in the first side pipeline, so that the dried desulfurization wastewater is dried into crystals.

Further, as shown in fig. 3, the method further includes:

and 304, discharging the flue gas after the desulfurization wastewater is concentrated into the wet desulfurization absorption tower for desulfurization.

And 305, discharging the flue gas subjected to the evaporation of the desulfurization wastewater into the dust remover and the wet desulfurization absorption tower in sequence to remove dust and perform desulfurization.

The method provided by the invention can be applied to the desulfurization wastewater treatment system as shown in fig. 1, and can obtain the same beneficial effects, and the method is not repeated herein for avoiding repetition.

Conventional technical knowledge in the art can be used for the details which are not described in the present invention.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited. Although the present invention has been described in detail with reference to the embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims.