CN205832922U - A kind of coalitenessity kiln gas Environmental-protection comprehensive processing system - Google Patents

Abstract

The utility model discloses an environmental protection comprehensive treatment system for low-temperature coke oven flue gas, which comprises an ammonia injection grid, a medium-low temperature SCR reactor, a catalyst, a waste heat recovery device, a first induced draft fan, a desulfurization tower, a bag-type dust removal device, and a second induced draft fan And the original chimney of the coke oven, the coke oven flue gas outlet is connected to the inlet of the medium and low temperature SCR reactor through the flue gas pipe, the ammonia injection grid is installed between the coke oven flue gas outlet and the SCR reactor, and the waste heat recovery device is installed in the medium and low temperature SCR The reactor and the induced draft fan 1 are directly connected through the flue gas pipeline. One end of the induced draft fan 1 is connected to the inlet of the desulfurization tower. The outlet of the tower is connected with the bag type dust removal device, the second induced draft fan and the original chimney of the coke oven in sequence through the flue gas pipeline. According to the characteristics of coke oven flue gas, the utility model adopts the integrated route of medium and low temperature SCR denitrification, waste heat recovery, semi-dry desulfurization and dust removal, effectively removes NOx, SO ₂ and dust in the flue gas, reduces operating costs and improves work efficiency ,Eco-friendly.

Description

A low-temperature coke oven flue gas environmental protection comprehensive treatment system

technical field

The utility model relates to the technical field of environmental protection treatment of industrial flue gas, in particular to an environmental protection comprehensive treatment system for low temperature coke oven flue gas.

Background technique

With the development of society, more and more attention has been paid to environmental protection, and the state has stricter requirements on the emission standards of air pollutants. Due to the low exhaust gas temperature in the coking industry (250-300°C), the traditional medium-high temperature SCR denitrification temperature is required to be above 300°C, so the flue gas temperature needs to be increased before denitrification to meet the denitrification temperature requirements.

The existing desulfurization methods can be divided into three types: dry method, semi-dry method and wet method. Dry desulfurization has low efficiency and produces many by-products, which basically cannot meet the existing emission standards at present; wet desulfurization has the highest effect and is more and more widely used in the coking industry, but it will cause secondary pollution and serious corrosion Equipment, high water consumption, large floor area, high investment and operation costs; semi-dry reaction product is dry powder, no secondary pollution, equipment corrosion problem is relatively light, and its desulfurization rate is between the former two. Traditional industrial flue gas denitrification generally adopts medium and high temperature SCR denitrification. Due to the low temperature of coke oven flue gas, the flue gas temperature must be increased before denitrification. Wet desulfurization is generally used for desulfurization, and the temperature loss is relatively large. When the purified flue gas is led to the original chimney for discharge, additional heat is required to increase the temperature of the flue gas.

At present, there is no suitable process route for the coking industry that can not only meet the new environmental protection requirements, but also reduce investment and operation costs.

Utility model content

The purpose of the utility model is to provide a low-temperature coke oven flue gas environmental protection comprehensive treatment system to solve the problems raised in the above-mentioned background technology.

In order to achieve the above object, the utility model provides the following technical solutions:

A low-temperature coke oven flue gas environmental protection comprehensive treatment system, including ammonia injection grid, medium and low temperature SCR reactor, catalyst, waste heat recovery device, induced draft fan 1, desulfurization tower, bag dust removal device, induced draft fan 2 and the original chimney of coke oven , the coke oven flue gas outlet is connected to the inlet of the medium and low temperature SCR reactor through the flue gas pipeline, and an ammonia injection grid is arranged between the coke oven flue gas outlet and the SCR reactor, and the catalyst in the medium and low temperature SCR reactor adopts "2+1" layer design mode, the waste heat recovery device is set between the medium and low temperature SCR reactor and the induced draft fan 1, and is directly connected through the flue gas pipeline, and one end of the induced draft fan 1 is connected to the inlet of the desulfurization tower, and the The inlet of the desulfurization tower is located at the lower part of one side of the desulfurization tower, and the outlet of the desulfurization tower is located at the upper part of the other side of the desulfurization tower. The outlet of the desulfurization tower is connected with the bag type dust removal device, the second induced draft fan and the original chimney of the coke oven in sequence through the flue gas pipeline.

The catalyst in the medium and low temperature SCR reactor adopts the "3+1" layer design mode instead of the "2+1" layer design mode.

The SO ₂ content of the coke oven flue gas that the medium-low temperature SCR reactor can handle is less than 600 mg/Nm ³ , and the dust content of the flue gas is less than 1000 mg/Nm ³ .

The desulfurization in the desulfurization tower is semi-dry desulfurization, using CaO as the desulfurizer.

Compared with the prior art, the beneficial effects of the utility model are:

1. The exhaust gas temperature in the coking industry is relatively low. Medium and low temperature SCR denitrification technology is used instead of medium and high temperature SCR denitrification technology. Coke oven flue gas does not need to be heated before entering the denitration reactor, thus saving energy consumption and reducing investment and operation costs.

2. The flue gas after desulfurization, denitrification and dust removal is introduced into the original chimney of the coke oven for discharge, and the temperature of the flue gas is required to be above 140°C. The semi-dry desulfurization method is used instead of the wet desulfurization commonly used in the coking industry to reduce temperature loss. Before being introduced into the original chimney of the coke oven No hot standby is required.

3. Compared with traditional wet desulfurization, the semi-dry desulfurization combined with bag dust removal can solve the problems of serious equipment corrosion, high investment and operation costs, and large heat loss while ensuring the desulfurization rate.

4. The establishment of the waste heat recovery device can recover part of the heat energy on the one hand, and on the other hand, it can control the inlet temperature of the desulfurization tower by controlling the steam pressure and output, so that the temperature in the desulfurization tower can be in a more suitable temperature range, and the desulfurization efficiency can be improved.

5. The integration of desulfurization and denitrification waste heat recovery can effectively remove NOx, SO ₂ , and dust in flue gas, reduce operating costs, improve work efficiency, and be environmentally friendly.

Description of drawings

Figure 1 is a schematic structural diagram of a low-temperature coke oven flue gas environmental protection comprehensive treatment system.

1: ammonia injection grid; 2: SCR reactor; 3: catalyst; 4: waste heat recovery device; 5: induced draft fan; 6: desulfurization tower; 7: bag dust removal device; 8: induced draft fan; 9: coke oven chimney.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. example. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

Please refer to Fig. 1, in the embodiment of the utility model, a low-temperature coke oven flue gas environmental protection comprehensive treatment system includes an ammonia injection grid 1, a medium-low temperature SCR reactor 2, a catalyst 3, a waste heat recovery device 4, and an induced draft fan-5 , desulfurization tower 6, bag type dedusting device 7, induced draft fan 2 8 and the original chimney 9 of the coke oven. An ammonia injection grid 1 is arranged between the reactors 2, and the catalyst 3 in the medium and low temperature SCR reactor 2 adopts two layers of catalysts installed, one layer is reserved for non-installation, or three layers of catalysts are installed, and one layer is reserved for non-installation The model, that is, "2+1" layer or "3+1" layer design pattern.

The waste heat recovery device 4 is arranged between the medium and low temperature SCR reactor 2 and the induced draft fan 5, and is directly connected through the flue gas pipeline. One end of the induced draft fan 5 is connected to the inlet of the desulfurization tower 6, and the inlet of the desulfurization tower 6 is It is located at the lower part of one side of the desulfurization tower 6, and the outlet of the desulfurization tower 6 is located at the upper part of the other side of the desulfurization tower 6. The outlet of the desulfurization tower 6 is connected with the bag type dust removal device 7, the induced draft fan 2 8 and the original chimney 9 of the coke oven in sequence through the flue gas pipeline connect.

The SO ₂ content of the coke oven flue gas that the medium-low temperature SCR reactor can handle is less than 600 mg/Nm ³ , and the dust content of the flue gas is less than 1000 mg/Nm ³ . The medium and low temperature SCR denitrification temperature is required to be between 180 and 300°C, and the coke oven flue gas temperature fully meets the denitrification reaction requirements, thus reducing the flue gas heating process. According to the flue gas temperature gradient, waste heat recovery is set after the denitrification reactor to improve energy utilization,

According to the characteristics of coke oven flue gas, the utility model adopts the integrated route of middle and low temperature SCR denitrification, waste heat recovery, semi-dry desulfurization and dust removal.

The desulfurization in the desulfurization tower 6 is semi-dry desulfurization, using CaO as the desulfurizer. Compared with traditional wet desulfurization, the semi-dry desulfurization combined with bag dust removal can solve the problems of serious equipment corrosion, high investment and operation costs, and large heat loss while ensuring the desulfurization rate.

The working principle of the utility model is:

After the coke oven flue gas is evenly mixed with the reducing agent gas ammonia sprayed into the ammonia injection grid 1 in the flue gas pipe, it enters the medium and low temperature SCR reactor 2, and NOx is reduced to _N2 and H2 under the action of the catalyst ₃ O, the flue gas after denitrification enters the waste heat recovery device 4, and uses the induced draft fan 5 to lead the flue gas to the desulfurization tower 6 for desulfurization. The flue gas after desulfurization contains more dust, so the bag dust removal device 7 will The dust is reduced to below the discharge standard, and the purified flue gas is led by the induced draft fan 8 to the original chimney 9 of the coke oven for discharge.

Gas ammonia is produced by evaporation of liquid ammonia, or by atomization of ammonia water.

It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from all points of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, so it is intended to fall within the scope of the claims All changes within the meaning and range of equivalents of the required elements are included in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only contains an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (2)

1. A low-temperature coke oven flue gas environmental protection comprehensive treatment system, characterized in that it includes ammonia injection grid, medium and low temperature SCR reactor, catalyst, waste heat recovery device, induced draft fan 1, desulfurization tower, bag type dust removal device, induced draft fan The original chimney of Erhe coke oven, the coke oven flue gas outlet is connected to the inlet of the medium and low temperature SCR reactor through the flue gas pipe, the ammonia injection grid is arranged between the coke oven flue gas outlet and the SCR reactor, and the waste heat recovery device It is installed between the medium and low temperature SCR reactor and the induced draft fan 1, and is directly connected through the flue gas pipeline. One end of the induced draft fan 1 is connected to the inlet of the desulfurization tower. It is located on the upper part of the other side of the desulfurization tower, and the outlet of the desulfurization tower is connected with the bag type dust removal device, the second induced draft fan and the original chimney of the coke oven in sequence through the flue gas pipeline. 2. The low-temperature coke oven flue gas environmental protection comprehensive treatment system according to claim 1, characterized in that the catalyst in the medium-low temperature SCR reactor adopts a "2+1" layer design mode.