Flue gas desulfurization and denitrification device for steel rolling heating furnace

Abstract

The utility model discloses a flue gas desulfurization and denitrification device for a steel rolling heating furnace. Comprising a heating furnace, a soot smoke treatment unit and an empty smoke treatment unit, the soot flue gas treatment unit comprises a steel rolling heating furnace soot flue, a soot primary heat exchanger, a soot desulfurization device, a soot secondary heat exchanger and a soot denitration device which are connected in sequence; the air-smoke flue gas treatment unit comprises a steel rolling heating furnace air-smoke flue, an air-smoke primary heat exchanger, an air-smoke desulfurization device, an air-smoke secondary heat exchanger and an air-smoke denitration device which are connected in sequence; a smoke outlet of the heating furnace is connected with a hot end air inlet of the soot secondary heat exchanger, a hot end air outlet of the soot secondary heat exchanger is connected with a hot end air inlet of the air-smoke secondary heat exchanger, and a hot end air outlet of the air-smoke secondary heat exchanger is connected with an air-smoke flue of the steel rolling heating furnace. The flue gas of the steel rolling heating furnace meets the flue gas emission requirement after being subjected to desulfurization and denitrification treatment, and has the advantages of low equipment investment and low operation cost.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas treatment and environmental protection equipment, in particular to a flue gas desulfurization and denitrification device for a steel rolling heating furnace. Background Art

[0002] Flue gas pollutants in the production process of steel rolling heating furnaces are an important source of pollutants in waste gas. In recent years, the country has paid particular attention to the pollution control in the metallurgical field. During the production process of steel rolling heating furnaces, sulfur oxides, nitrogen oxides and particulate matter are produced, which seriously endanger the environment in which we live. Problems such as acid rain and haze occur frequently. At present, the flue gas treatment guidance standard makes clear requirements on the emission concentration of flue gas pollutants in steel rolling heating furnaces, that is, NO in the flue gas. x <50mg / m 3 、SO2<35mg / m 3 , particulate matter <10mg / m 3 .

[0003] There are many technologies for desulfurization and denitrification of flue gas from steel rolling heating furnaces at home and abroad. Desulfurization includes traditional wet, dry and semi-dry technologies. Among them, wet desulfurization technologies include limestone gypsum method, ammonia method, magnesium method, etc., and dry and semi-dry desulfurization technologies include CFB desulfurization, SDS desulfurization, dense phase tower desulfurization, SDA desulfurization and fixed bed dry desulfurization. Denitrification technologies mainly include SCR, SNCR and low nitrogen combustion technology. The combined technology used is also mostly SDS desulfurization + SCR denitrification process route.

[0004] The flue gas temperature of the steel rolling heating furnace is low, and the original concentration of pollutants is low. Most of them adopt the SDS desulfurization process + SCR denitrification process. Since desulfurization and denitrification require a certain temperature, especially the SCR catalyst, the air flue gas and coal smoke flue gas temperatures of the steel rolling heating furnace are not enough, and multi-stage heat exchange and supplementary heat are required to meet the temperature window required by SCR. The inventor of this application found that if two heating furnaces are set up to heat and supplement the air flue gas and coal smoke respectively, more coal gas will be consumed. If only the coal smoke flue gas is heat exchanged, and the flue gas of the heating furnace is not properly handled after the heat exchange, the concentration of SO2 emitted from the air flue will increase. Utility Model Content

[0005] According to one embodiment of the utility model, the purpose is to provide a new type of flue gas desulfurization and denitrification device for steel rolling heating furnace, so as to desulfurize and denitrify the coal smoke and air smoke of the steel rolling heating furnace. The above purpose can be achieved through the following technical solutions:

[0006] According to one aspect of the utility model, the utility model provides a steel rolling heating furnace flue gas desulfurization and denitrification device, comprising: a heating furnace, a coal smoke and flue gas treatment unit and an air smoke and flue gas treatment unit;

[0007] Among them, the coal smoke flue gas treatment unit includes: a coal smoke flue, a coal smoke primary heat exchanger, a coal smoke desulfurization device, a coal smoke secondary heat exchanger and a coal smoke desulfurization device of a steel rolling heating furnace connected in sequence; the air smoke flue gas treatment unit includes: an air smoke flue, a first air smoke heat exchanger, an air smoke desulfurization device, a second air smoke heat exchanger and an air smoke desulfurization device of a steel rolling heating furnace connected in sequence; the flue gas outlet of the heating furnace is connected to the hot end air inlet of the coal smoke secondary heat exchanger, and the hot end air outlet of the coal smoke secondary heat exchanger is connected to the hot end air inlet of the air smoke secondary heat exchanger; the hot end air outlet of the air smoke secondary heat exchanger is connected to the air smoke flue of the steel rolling heating furnace.

[0008] Optionally, the outlet of the soot removal device is connected to the hot end air inlet of the soot primary heat exchanger.

[0009] Optionally, the outlet of the air-smoke deoxidation device is connected to the hot end air inlet of the air-smoke primary heat exchanger.

[0010] Optionally, a coal smoke fan is also included, and the hot end air outlet of the coal smoke primary heat exchanger is connected to the coal smoke fan, and the air outlet of the coal smoke fan is connected to the coal smoke chimney.

[0011] Optionally, an air smoke fan is also included, and the hot end air outlet of the air smoke primary heat exchanger is connected to the air smoke fan, and the air outlet of the air smoke fan is connected to the air smoke chimney.

[0012] Optionally, the coal smoke desulfurization device and the air smoke desulfurization device are both SDS desulfurization devices.

[0013] Optionally, the soot de-elimination device and the air smoke de-elimination device are both SCR de-elimination devices.

[0014] Optionally, a soot temperature detector is also included, which is respectively connected to the cold end outlet of the soot primary heat exchanger and the soot secondary heat exchanger.

[0015] Optionally, an air-smoke temperature detector is also included, which is respectively connected to the cold end outlet of the air-smoke primary heat exchanger and the air-smoke secondary heat exchanger.

[0016] Beneficial effect: According to the steel rolling heating furnace flue gas desulfurization and denitrification device in one embodiment of the utility model, an independent heating furnace is set up, and the coal smoke and air smoke are used for secondary heat exchange and heat supplement, which meets the desulfurization and denitrification treatment requirements of the coal smoke and air smoke; and the flue gas of the heating furnace after heat exchange is connected to the untreated air smoke flue and is desulfurized and denitrified together with the air smoke of the steel rolling heating furnace, thereby reducing the emission concentration of SO2 from the chimney. The utility model only needs one heating furnace, less system equipment, and low operating cost. It is a new type of flue gas desulfurization and denitrification treatment device for steel rolling heating furnaces.

[0017] Compared with the prior art, some embodiments of the present invention also have the following advantages:

[0018] 1) The utility model adopts a unique heat exchange and heat supplement system, sets a separate heating furnace, two sets of secondary heat exchangers, and desulfurizes and denitrates the flue gas after heat exchange in the heating furnace, which saves gas consumption and reduces the pollutant concentration in the chimney caused by the mixing of flue gas after combustion in the heating furnace. It is a new type of high-efficiency and energy-saving desulfurization and denitrification device for steel rolling heating furnace.

[0019] 2) The utility model adopts an SDS desulfurization device, which can realize the dual functions of desulfurization and dust removal, achieve the requirements of ultra-low emissions, avoid the ultra-low temperature of dust caused by the pulverization of desulfurization agents in dry fixed bed desulfurization, and the many problems such as difficult system matching and whitening caused by wet desulfurization.

[0020] 3) The utility model has a simple device, has no complicated equipment structure, reduces investment and operation costs, and is easy to maintain and use.

[0021] 4) The utility model connects the outlet of the soot and / or air smoke denitrification device to the hot end air inlet of the soot and / or air smoke primary heat exchanger, and uses the smoke after denitrification treatment as the heat source for the primary heat exchange, saving heat exchange energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of a flue gas desulfurization and denitrification device for a steel rolling heating furnace according to an embodiment of the utility model. In the accompanying drawings: 7. Heating furnace; 20. Coal smoke flue of the steel rolling heating furnace; 30. Air smoke flue of the steel rolling heating furnace;

[0023] 1. Coal smoke desulfurization device; 2. Coal smoke primary heat exchanger; 3. Coal smoke secondary heat exchanger; 4. Coal smoke denitrification device; 5. Coal smoke fan; 6. Coal smoke chimney;

[0024] 8. Air smoke desulfurization device; 9. Air smoke primary heat exchanger; 10. Air smoke secondary heat exchanger; 11. Air smoke denitrification device; 12. Air smoke fan; 13. Coal smoke chimney. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the utility model to clearly and completely describe the technical solution of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation on the utility model and its application or use. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] A flue gas desulfurization and denitrification device for a steel rolling heating furnace provided in one embodiment of the utility model comprises a coal smoke and flue gas treatment unit and an air smoke and flue gas treatment unit with two-stage heat exchange, and a heating furnace. The coal smoke and flue gas treatment unit comprises a coal smoke flue, a primary coal smoke heat exchanger, a coal smoke desulfurization device, a secondary coal smoke heat exchanger and a coal smoke denitrification device of the steel rolling heating furnace connected in sequence. The air smoke and flue gas treatment unit comprises an air smoke flue, a primary air smoke heat exchanger, an air smoke desulfurization device, a secondary air smoke heat exchanger and an air smoke denitrification device of the steel rolling heating furnace connected in sequence. The flue gas outlet of the heating furnace is connected to the hot end air inlet of the secondary coal smoke heat exchanger, the hot end air outlet of the secondary coal smoke heat exchanger is connected to the hot end air inlet of the secondary air smoke heat exchanger, and the hot end air outlet of the secondary air smoke heat exchanger is connected to the air smoke flue of the steel rolling heating furnace. The device only sets up an independent heating furnace, which is used to perform secondary heat exchange and heat supplement for coal smoke and air smoke, thus meeting the desulfurization and denitrification treatment needs of coal smoke and air smoke; and the flue gas from the heating furnace after heat exchange is connected to the flue of untreated air smoke and is desulfurized and denitrified together with the air smoke from the steel rolling heating furnace, thereby reducing the SO2 emission concentration of the chimney; the system has few equipment and low operating costs, and is a new type of flue gas desulfurization and denitrification treatment device for steel rolling heating furnaces.

[0027] Figure 1 A steel rolling heating furnace flue gas desulfurization and denitration device provided in a preferred embodiment of the present application is schematically shown. The device includes: a heating furnace, a steel rolling heating furnace coal smoke flue, a coal smoke desulfurization device, a coal smoke primary heat exchanger, a coal smoke secondary heat exchanger, a coal smoke denitration device, a coal smoke induced draft fan, a coal smoke chimney, a steel rolling heating furnace air smoke flue, an air smoke desulfurization device, an air smoke primary heat exchanger, an air smoke secondary heat exchanger, an air smoke denitration device, an air smoke induced draft fan, and an air smoke chimney.

[0028] like Figure 1 As shown, the coal smoke flue of the steel rolling heating furnace is connected to the coal smoke primary heat exchanger, the air outlet at the cold end of the coal smoke primary heat exchanger is connected to the air inlet of the coal smoke desulfurization device, the air inlet at the cold end of the coal smoke secondary heat exchanger is connected to the air outlet of the coal smoke desulfurization device, the coal smoke denitrification device is connected to the air outlet at the cold end of the coal smoke secondary heat exchanger, the air inlet at the hot end of the coal smoke primary heat exchanger is connected to the outlet of the coal smoke denitrification device, the air outlet at the hot end of the coal smoke primary heat exchanger is connected to the coal smoke fan, and the air outlet of the coal smoke fan is connected to the coal smoke chimney.

[0029] The smoke outlet of the hot blast stove is connected to the hot end air inlet of the coal smoke secondary heat exchanger, and the hot end air inlet of the air smoke secondary heat exchanger is connected to the hot end air outlet of the coal smoke secondary heat exchanger.

[0030] The air smoke duct of the steel rolling heating furnace is connected to the first-level air smoke heat exchanger, the air outlet at the cold end of the first-level air smoke heat exchanger is connected to the air inlet of the air smoke desulfurization device, the air inlet at the cold end of the second-level air smoke heat exchanger is connected to the air outlet of the air smoke desulfurization device, the air smoke denitrification device is connected to the cold end outlet of the second-level air smoke heat exchanger, the air inlet at the hot end of the first-level air smoke heat exchanger is connected to the outlet of the air smoke denitrification device, the air outlet at the hot end of the first-level air smoke heat exchanger is connected to the air smoke fan, the air outlet of the air smoke fan is connected to the air smoke chimney, the air inlet at the hot end of the second-level air smoke heat exchanger is connected to the hot end outlet of the second-level coal smoke heat exchanger, and the hot end outlet of the second-level air smoke heat exchanger is connected to the air smoke duct of the steel rolling heating furnace.

[0031] When the device of this embodiment is used for desulfurization and denitrification treatment, it is possible to reasonably supplement heat and exchange heat for the flue gas and effectively utilize energy. A hot blast furnace is provided to perform secondary heat supplement for air flue gas and coal smoke flue gas, and the hot blast furnace flue gas is simultaneously treated without generating additional pollutants. The heat supplement and heat exchange system of the entire scheme is stable, efficient and environmentally friendly.

[0032] In addition, in a preferred embodiment, the coal smoke desulfurization device and the air smoke desulfurization device adopt an SDS desulfurization device, and the coal smoke denitrification device and the air smoke denitrification device adopt an SCR denitrification device. Based on the combination of SDS desulfurization + SCR denitrification, the coal smoke flue gas and air smoke flue gas of the steel rolling heating furnace are desulfurized and denitrified.

[0033] refer to Figure 1 As shown, the flue gas of the steel rolling heating furnace is divided into air flue gas and coal smoke flue gas. Therefore, two independent desulfurization and denitrification devices, namely the air flue gas treatment unit and the coal smoke flue gas treatment unit, are equipped for separate treatment. Among them, since the flue gas temperature of the steel rolling heating furnace is relatively low and cannot meet the temperature required for SDS desulfurization, such as above 140°C, it is necessary to perform a primary heat exchange on the air flue gas and the coal smoke flue gas of the steel rolling heating furnace, and enter the desulfurization device after the heat exchange reaches the required temperature for desulfurization. The air flue gas and the coal smoke flue gas are both equipped with a primary heat exchanger, and the heat source of the primary heat exchanger comes from the clean flue gas after denitrification.

[0034] In addition, the flue gas after desulfurization cannot meet the required temperature for denitrification, such as 220℃. A secondary heat exchanger is set for the coal smoke flue gas and air smoke to raise the temperature to the required temperature for denitrification. The heat source of the secondary heat exchange comes from the high-temperature flue gas of the heating furnace. After the heat exchange, the high-temperature flue gas of the heating furnace enters the air smoke flue of the steel rolling heating furnace before the air-smoke primary heat exchanger. It can be desulfurized and denitrified together with the air smoke of the steel rolling heating furnace. The clean flue gas after denitrification is used as the heat source of the primary heat exchanger and is discharged into the chimney from the fan after heat exchange.

[0035] In addition, a temperature detector can be installed at the cold end outlet of each heat exchanger to detect the flue gas temperature after heat exchange so as to meet the SDS desulfurization or SCR desulfurization treatment. For example, if the temperature drops slightly, the heat source temperature can be appropriately increased.

[0036] Since the flue gas temperature of the steel rolling heating furnace is reduced, it is necessary to exchange heat and supplement heat for the flue gas before and after desulfurization. In this embodiment, multiple flue gas heat exchangers and a heating furnace are set to exchange heat and supplement heat for the flue gas, and an SDS desulfurization device and an SCR denitrification device are used for desulfurization and denitrification. The temperature conditions required for SDS desulfurization and SCR denitrification can be met, the flue gas treatment efficiency is improved, and the exhaust flue gas meets the low emission requirements.

[0037] In addition, the desulfurization and denitrification device in the utility model can be arranged between the steel rolling heating furnace and the fan. After testing, the desulfurization efficiency is 98% and above, and the denitrification efficiency is 95% and above. It can adapt to the flue gas desulfurization and denitrification treatment under various working conditions of the steel rolling heating furnace, and can achieve 100-200mg / Nm 3 SO2 removal to 35mg / Nm 3 And below, the dust concentration is controlled at 10mg / Nm 3 Within, achieve 100 ~ 200mg / Nm 3 NO x Remove to 50mg / Nm 3 And below, the desulfurization and denitrification efficiency is high, the operation and maintenance are simple, and the energy consumption is low.

[0038] The following is a description of the process of treating flue gas using the flue gas desulfurization and denitrification device for a steel rolling heating furnace according to the utility model in conjunction with an application example.

[0039] Specifically, the device is applied to the Tiantie project. The initial SO2 concentration of the flue gas from the steel rolling heating furnace of the Tiantie project is 150mg / Nm 3 , NO X Concentration 150~300mg / Nm 3 , the flue gas temperature is 70~120℃.

[0040] Treatment process: The coal smoke flue gas and the air smoke flue gas are subjected to primary heat exchange through the coal smoke primary heat exchanger and the air smoke primary heat exchanger respectively. When the flue gas heat exchange reaches 180°C, the flue gas enters the coal smoke desulfurization device and the air smoke desulfurization device for SDS desulfurization, wherein the desulfurizer can be baking soda. The flue gas after desulfurization and dust removal enters the coal smoke secondary heat exchanger and the air smoke secondary heat exchanger for secondary heat exchange. When the flue gas heat exchange reaches 220°C, the flue gas enters the coal smoke denitrification device and the air smoke denitrification device for SCR denitrification, wherein the denitrification agent can be ammonia water. The flue gas after denitrification is used as the heat source of the coal smoke primary heat exchanger and the air smoke primary heat exchanger respectively, and then discharged into the chimney through the fan. In addition, the fuel used by the heating furnace is blast furnace gas, and the flue gas of the heating furnace is 600℃, which is sent into the coal smoke secondary heat exchanger. After the secondary heat exchange of the coal smoke, the flue gas of the heating furnace is reduced to 400℃, and then enters the air smoke secondary heat exchanger for secondary heat exchange of the air smoke. After the secondary heat exchange of the air smoke, the heating furnace flue gas enters the air smoke flue of the steel rolling heating furnace for subsequent desulfurization and denitrification treatment together with the air smoke of the steel rolling heating furnace.

[0041] After testing, the application example controls the SO2 concentration of flue gas to 35mg / Nm by using the above desulfurization and denitrification device. 3 , dust control to 10mg / Nm 3 , NO x The concentration is controlled at 50mg / Nm 3 , achieving SO2, NO x The ultra-low emission requirements of 35, 50, and 10 for air and dust are met; the treated flue gas is discharged into the atmosphere through the fan, reducing pollution to the environment.

[0042] In summary, in the above embodiments of the utility model, the device is simple, without complicated equipment structure, and is easy to maintain and use. The utility model is a new type of heat exchange and heat supplement form, which can reasonably supplement and exchange flue gas heat for desulfurization and denitrification, effectively utilize energy comprehensively, reduce gas consumption, avoid the generation of additional pollutants and other problems, and is a new type of efficient, stable and environmentally friendly device; by setting a hot blast furnace to perform secondary heat supplement for air smoke and coal smoke, and synchronously treat the hot blast furnace flue gas, no additional pollutants are generated, and the heat supplement and heat exchange system of the whole scheme is stable, efficient and environmentally friendly; the utility model solves the treatment of flue gas pollutants in steel rolling heating furnace, and has good desulfurization and denitrification efficiency, with a desulfurization efficiency of more than 98% and a denitrification efficiency of more than 95%, achieving the ultra-low emission requirements of flue gas desulfurization and denitrification, and the dust concentration of the flue gas of the steel rolling heating furnace after being treated by the utility model device is ≤10mg / Nm 3 , SO2 concentration ≤35mg / Nm 3 , NOx concentration ≤50mg / Nm 3 .

[0043] The description of the present invention is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the present invention to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and design various embodiments with various modifications suitable for specific uses.

Claims

1. A flue gas desulfurization and denitrification device for steel rolling heating furnace, characterized in that: include: A heating furnace, a coal smoke and fume treatment unit and an air smoke and fume treatment unit, wherein: The soot and flue gas treatment unit comprises: a soot duct of a steel rolling heating furnace, a soot primary heat exchanger, a soot desulfurization device, a soot secondary heat exchanger and a soot desulfurization device which are connected in sequence; The air smoke and flue gas treatment unit comprises: an air smoke flue of a steel rolling heating furnace, an air smoke primary heat exchanger, an air smoke desulfurization device, an air smoke secondary heat exchanger and an air smoke desulfurization device which are connected in sequence; The flue gas outlet of the heating furnace is connected to the hot end air inlet of the coal smoke secondary heat exchanger, and the hot end air outlet of the coal smoke secondary heat exchanger is connected to the hot end air inlet of the air smoke secondary heat exchanger; the hot end air outlet of the air smoke secondary heat exchanger is connected to the air smoke flue of the steel rolling heating furnace.

2. The flue gas desulfurization and denitrification device for steel rolling heating furnace according to claim 1, characterized in that: The outlet of the soot removal device is connected to the hot end air inlet of the soot primary heat exchanger.

3. The flue gas desulfurization and denitrification device for steel rolling heating furnace according to claim 1, characterized in that: The outlet of the air-smoke deoxidation device is connected to the hot end air inlet of the air-smoke primary heat exchanger.

4. The flue gas desulfurization and denitrification device for steel rolling heating furnace according to claim 1, characterized in that: It also includes a coal smoke fan, the hot end air outlet of the coal smoke primary heat exchanger is connected to the coal smoke fan, and the coal smoke fan outlet is connected to the coal smoke chimney.

5. The flue gas desulfurization and denitrification device for steel rolling heating furnace according to claim 1, characterized in that: It also includes an air-smoke fan, the hot end air outlet of the air-smoke primary heat exchanger is connected to the air-smoke fan, and the air outlet of the air-smoke fan is connected to the air-smoke chimney.

6. The flue gas desulfurization and denitrification device for steel rolling heating furnace according to claim 1, characterized in that: The coal smoke desulfurization device and the air smoke desulfurization device are both SDS desulfurization devices.

7. The flue gas desulfurization and denitrification device for steel rolling heating furnace according to claim 1, characterized in that: The soot removal device and the air smoke removal device are both SCR removal devices.

8. The flue gas desulfurization and denitrification device for steel rolling heating furnace according to claim 1, characterized in that: It also includes a soot temperature detector which is respectively connected to the cold end air outlets of the soot primary heat exchanger and the soot secondary heat exchanger.

9. The flue gas desulfurization and denitrification device for steel rolling heating furnace according to claim 1, characterized in that: It also includes an air-smoke temperature detector which is respectively connected to the cold end air outlets of the air-smoke primary heat exchanger and the air-smoke secondary heat exchanger.

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