CN214513705U

CN214513705U - Complicated flue gas purification system

Info

Publication number: CN214513705U
Application number: CN202023301451.9U
Authority: CN
Inventors: 闫龙; 朱清亮; 苏海军; 田勤; 张卫国; 张翠
Original assignee: China Chemical Engineering Second Construction Corp
Current assignee: China Chemical Engineering Second Construction Corp
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2021-10-29
Anticipated expiration: 2030-12-31

Abstract

The utility model relates to a complex flue gas purification system, which comprises a desulfurization filtering device, an SCR denitration device, an ammonia spraying device and a flue gas emission device; the flue gas outlet of the desulfurization filtering device and the ammonia spraying device are both connected with the flue gas inlet of the SCR denitration device, and the flue gas outlet of the SCR denitration device is connected with the flue gas discharge device; and a waste heat recovery device is connected between the SCR denitration device and the flue gas discharge device. Sulfur dioxide and other pollutants can be absorbed in the desulfurization filter device, and a large amount of water can be absorbed, so that the discharge of water vapor can be reduced, and the aim of whitening can be fulfilled; when sulfur dioxide and water vapor are removed, a large amount of reaction heat can be released, and the defect that the temperature of the SCR denitration flue gas is low at the rear end due to heat loss can be overcome. The utility model discloses can satisfy more complicated gas cleaning requirement, the process route is shorter, the device is simple, need not to increase flue gas reheating system separately, helps reducing the running cost.

Description

Complicated flue gas purification system

Technical Field

The utility model relates to a technical field is administered to the flue gas, particularly, is a complicated gas cleaning system.

Background

The flue gas generated by fuel combustion mainly discharges sulfur dioxide, nitrogen oxide and particulate matters. The treatment mode is basically different combination forms of three devices of desulfurization, denitration and dust removal. However, in different industries, different combustion devices and different working conditions, the flue gas may contain some other pollutants or components affecting desulfurization, denitrification and dust removal efficiency, such as: water, heavy metals, tar, carbon black, etc., and additional facilities are required to treat these component substances in order to solve these problems.

At present, for the thermal power industry, most enterprises still adopt medium-temperature SCR denitration, electric bag or cloth bag dust removal and wet desulphurization, although the process combination is mature, the moisture content of flue gas discharged by the wet desulphurization is high, a dehydration and whitening device needs to be additionally arranged in a part of areas, and the wastewater generated by the wet desulphurization is difficult to treat.

When the flue gas is subjected to SCR denitration without desulfurization in the coking and metallurgy industries due to low flue gas temperature, high water content and complex flue gas components, ammonium sulfate or ammonium bisulfate is easily generated in the ammonia spraying process to cause SCR catalyst poisoning. Therefore, dry or semi-dry desulfurization, cloth bag dust removal and low-temperature SCR denitration combined processes are mostly adopted.

The common dry and semi-dry desulfurization methods adopt sodium bicarbonate as a desulfurizer, so that water and other pollutants in the flue gas cannot be removed simultaneously, the water content in the flue gas is high, the denitration efficiency of the denitration catalyst is affected, and in addition, for some areas requiring whitening, a whitening device needs to be newly arranged on the flue gas. In addition, the coke oven working condition of part coking enterprises is poor, substances such as tar and carbon black are easy to enter flue gas, and the substances are easy to attach to a cloth bag of a dust remover and an SCR denitration catalyst, so that the dust remover is blocked and the SCR denitration catalyst is poisoned and inactivated.

And active carbon/coke is adopted for desulfurization, although most pollutants and moisture in the flue gas can be absorbed, the active carbon/coke has higher relative price, the device is large, and the operating cost is high.

For a system with lower flue gas temperature, if the system has poorer heat preservation and larger flue gas temperature drop by adopting the desulfurization mode, a flue gas reheating system is required to be added for meeting the denitration temperature requirement.

Disclosure of Invention

The to-be-solved technical problem of the utility model is to provide a complicated gas cleaning system that the process route is short, and the device is simple.

In order to solve the technical problems, the utility model provides a complex flue gas purification system, which comprises a desulfurization filtering device, an SCR denitration device, an ammonia spraying device and a flue gas emission device; the flue gas outlet of the desulfurization filtering device and the ammonia spraying device are both connected with the flue gas inlet of the SCR denitration device, and the flue gas outlet of the SCR denitration device is connected with the flue gas discharge device; and a waste heat recovery device is connected between the SCR denitration device and the flue gas discharge device.

Further, a vertically arranged moving bed for placing desulfurization filtering agent is arranged in the desulfurization filtering device.

Further, a fixed bed for placing an SCR denitration catalyst is arranged in the SCR denitration device.

Furthermore, an induced draft fan is connected between the waste heat recovery device and the smoke discharge device.

Furthermore, a desulfurization filtering agent feeding device is arranged at the top of the desulfurization filtering device, and a desulfurization filtering agent discharging device is arranged at the bottom of the desulfurization filtering device.

Compared with the prior art, firstly, the moving bed desulfurization filter device can simultaneously remove sulfur dioxide, dust and other pollutants to avoid damage to the SCR denitration catalyst; secondly, sulfur dioxide and other pollutants can be absorbed in the desulfurization filter device, and a large amount of moisture can be absorbed, so that the emission of water vapor can be reduced, and the aim of whitening can be achieved; thirdly, the desulfurization filter equipment can release a large amount of reaction heat while removing sulfur dioxide and water vapor, and can make up the deficiency that the flue gas temperature is lower because of the SCR denitration at the rear end of the heat loss.

The utility model discloses can satisfy more complicated gas cleaning requirement, the process route is shorter, the device is simple, need not to increase flue gas reheating system separately, helps reducing the running cost.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention in any way.

Fig. 1 is a schematic structural diagram of a complex flue gas purification system provided by the present invention.

In the figure, 1-a desulfurization filter device, 2-an SCR denitration device, 3-an ammonia spraying device, 4-a flue gas discharge device, 5-a moving bed, 6-a fixed bed, 7-a waste heat recovery device, 8-an induced draft fan, 9-a desulfurization filtering agent feeding device, 10-a desulfurization filtering agent discharging device and 11-a flue gas pipeline.

Detailed Description

In order to make the present invention better understood by those skilled in the art, the present invention will be further clearly and completely described below with reference to the accompanying drawings and embodiments. In addition, the features of the embodiments and examples in the present application may be combined with each other without conflict.

The utility model relates to a typical embodiment provides a complex flue gas purification system, which comprises a desulfurization filtering device 1, an SCR denitration device 2, an ammonia spraying device 3 and a flue gas discharge device 4; the flue gas outlet of the desulfurization filtering device 1 and the ammonia spraying device 3 are both connected with the flue gas inlet of the SCR denitration device 2, and the flue gas outlet of the SCR denitration device 2 is connected with the flue gas discharge device 4. And a waste heat recovery device 7 is connected between the SCR denitration device 2 and the flue gas discharge device 4.

In the above embodiment, the waste heat recovery device 7 is a waste heat recovery boiler, the induced draft fan 8 is connected between the waste heat recovery device 7 and the flue gas emission device 4, and the waste heat recovery device 7 is used for recovering partial flue gas heat and can generate partial steam as a byproduct. The ammonia injection device 3 mainly provides a denitration reducing agent for the SCR denitration device. The middle lower part of the desulfurization filtering device 1 is provided with a flue gas inlet which is connected with a flue gas pipeline 11 for inputting flue gas.

The temperature of the flue gas involved in the embodiment is not lower than the temperature range required by desulfurization and denitration, and is usually 220-320 ℃. According to the above embodiment, the complex flue gas firstly enters the moving bed desulfurization filtering device 1 through the flue gas pipeline 11 to remove sulfur dioxide, dust and other pollutants in the flue gas; flue gas after desulfurization and purification enters the SCR denitration device 2 through the flue gas pipeline 11, the flue gas is mixed with ammonia gas from the ammonia spraying system 3 in the SCR denitration device 2, nitrogen oxide in the flue gas is reduced into nitrogen gas and water, and the flue gas after the desulfurization and purification is discharged after reaching the standard through the draught fan 8 and the flue gas discharge device 4 after recycling part of heat through the waste heat recovery device 7.

In a preferred embodiment, a vertically arranged moving bed 5 for placing desulfurization filtering agent is arranged inside the desulfurization filtering device 1, and the desulfurization filtering agent can move from top to bottom by means of gravity. The top of the desulfurization filtering device 1 is provided with a desulfurization filtering agent feeding device 9, and the bottom of the desulfurization filtering device 1 is provided with a desulfurization filtering agent discharging device 10. The desulfurization filter device 1 is filled with a desulfurization filter agent which is a calcium oxide-based porous columnar particle composite material, has the functions of removing sulfur dioxide and adsorbing other substances, and can absorb a large amount of water in the flue gas. The desulfurization filtering agent is loaded from the upper part through the feeding device, moves from the top to the bottom according to the gravity and is discharged from the bottom through the desulfurization filtering agent discharging device.

The inside fixed bed 6 that is used for placing SCR denitration catalyst that is provided with of SCR denitrification facility 2. And selecting a medium-temperature or low-temperature SCR denitration catalyst according to the temperature of the flue gas.

The scope of the invention is not limited to the above embodiments, and various modifications and changes may be made by those skilled in the art, and any modifications, improvements and equivalents made within the spirit and principle of the invention are intended to be included within the scope of the invention.

Claims

1. A complex flue gas purification system is characterized by comprising a desulfurization filtering device, an SCR denitration device, an ammonia spraying device and a flue gas emission device; the flue gas outlet of the desulfurization filtering device and the ammonia spraying device are both connected with the flue gas inlet of the SCR denitration device, and the flue gas outlet of the SCR denitration device is connected with the flue gas discharge device; a waste heat recovery device is connected between the SCR denitration device and the flue gas discharge device; a vertically arranged moving bed for placing desulfurization filtering agent is arranged in the desulfurization filtering device; the SCR denitration device is internally provided with a fixed bed for placing an SCR denitration catalyst.

2. The complex flue gas purification system of claim 1, wherein: and an induced draft fan is connected between the waste heat recovery device and the smoke discharge device.

3. The complex flue gas purification system of claim 2, wherein: the top of the desulfurization filtering device is provided with a desulfurization filtering agent feeding device, and the bottom of the desulfurization filtering device is provided with a desulfurization filtering agent discharging device.