CN115105935A - Flue gas desulfurization and denitrification system and method for blast furnace hot blast stove - Google Patents

Abstract

The invention provides a flue gas desulfurization and denitrification system and method for a blast furnace hot blast stove. The system includes a hot blast stove, an inlet NOx content detection device, a hot blast stove preheater, a first desulfurization agent conveying switching device, a second desulfurizing agent conveying and switching device, and a denitrification device. A reducing agent injection device and a desulfurization, denitrification and dust removal device; the flue gas outlet of the hot blast stove is connected to the inlet of the hot blast stove preheater through the original flue through the inlet NOx content detection device and the original flue cut-off valve in turn; the first desulfurization agent conveying switching device It is used to spray the desulfurizer into the original flue; its flue gas outlet is also connected to the flue gas inlet of the desulfurization, denitrification and dust removal device through the inlet flue through the inlet flue cut-off valve, and its flue gas outlet is cut off through the outlet flue. The valve is connected with the inlet of the preheater of the hot blast stove; the second desulfurization agent conveying switching device is connected with the desulfurization agent injection port of the desulfurization, denitrification and dust removal device through the pipeline; agent.

Description

A blast furnace hot blast stove flue gas desulfurization and denitrification system and method

technical field

The invention relates to a system and method for desulfurization and denitration of flue gas of a blast furnace hot blast stove, and belongs to the technical field of flue gas treatment.

Background technique

Iron and steel enterprises have many processes, and the composition of flue gas emissions is complex, and the pollutant emission control methods applicable to different processes are different; practitioners in the industry are constantly developing and innovating the best flue gas treatment methods suitable for the characteristics of each process, and the technical route is frequently replaced. In order to achieve the purpose of effective governance and economical energy saving. Blast furnace hot blast stoves serve for blast furnace blast heating, and there are a large number of them. At the same time, blast furnace hot blast stove flue gas has new characteristics, and new treatment schemes and emission reduction methods need to be studied.

The flue gas emission of each blast furnace hot blast stove is generally 150,000-400,000 Nm ³ /h, and the concentration of SO ₂ and NOx in the flue gas generally does not exceed 200 mg/Nm ³ , but due to the large number of blast furnaces, the total emissions cannot be tolerated. ignore. At present, some hot blast stoves have added flue gas desulfurization and denitrification treatment devices. The desulfurization processes adopted are mainly fixed bed desulfurization and SDS desulfurization, and the denitration methods are mainly medium temperature SCR denitration and fixed bed. Among them, the fixed bed desulfurization and denitrification technology does not produce waste water, but the denitration efficiency of this method is not high. To achieve ultra-low NOx emissions, a large amount of denitrification agent needs to be invested, which will increase the investment cost; while the SDS desulfurization method requires Ensure that the flue gas temperature is above 140 ℃ to have good removal efficiency. In addition, because the medium and low temperature SCR denitration technology is limited by the temperature window, the flue gas needs to be heated to above 200-280 °C. For this reason, the system needs to add a heating device and a large heat exchanger, which leads to an increase in overall investment and energy consumption for system operation. rise.

Prior art one related to the present invention:

The technical solution of the existing technology 1:

Chinese patent CN211936312U discloses a blast furnace hot blast furnace waste gas desulfurization and denitrification system, which adopts dry desulfurization and removal of SO ₂ , and uses low-temperature SCR denitration catalyst to catalyze the removal of NOx in flue gas. The desulfurization tower and bag filter are arranged in the denitrification. On the upstream side of the reactor, a hot blast stove component is installed on the side wall of the main frame of the denitration reactor, which can control the temperature of the flue gas to a certain extent, so that it can meet the better catalytic effect. If the exhaust gas temperature is lower than the optimal catalytic temperature of the catalyst, High temperature flue gas is injected through the hot air distribution pipe to increase the temperature of the exhaust gas.

Disadvantages of prior art one:

In this technology, the dry process is used for desulfurization at the end of the hot blast stove system, and the adverse effects of the low temperature of the flue gas of the hot blast stove on the desulfurization efficiency are not considered. As the temperature increases, a large amount of external heat source is consumed, and the operating cost increases.

Prior art two related to the present invention:

The technical solution of the existing technology 2:

Chinese patent CN215233228U discloses an automatic desulfurization device for hot blast stove flue gas, which is used to solve the problem of waste or excessive sulfur dioxide emission caused by unreasonable input of desulfurizer in the process of hot blast stove flue gas desulfurization.

Disadvantages of the existing technology two:

This technology only studies the scheme of automatically adjusting the input amount of desulfurizer. Although a new type of desulfurizer is used for desulfurization, the desulfurization effect is not clarified, and no technical scheme for the characteristics of hot blast stove flue gas is proposed.

Therefore, it has become an urgent technical problem to be solved in this field to provide a novel high-efficiency, stable, and low-energy-consumption blast furnace hot blast stove flue gas desulfurization and denitrification system and method.

SUMMARY OF THE INVENTION

In order to solve the above shortcomings and deficiencies, one object of the present invention is to provide a flue gas desulfurization and denitrification system for a blast furnace hot blast stove.

Another object of the present invention is to provide a method for desulfurization and denitrification of flue gas from a blast furnace hot blast stove.

In order to achieve the above purpose, on the one hand, the present invention provides a flue gas desulfurization and denitrification system for a blast furnace hot blast stove, wherein the system for flue gas desulfurization and denitrification of a blast furnace hot blast stove includes: a hot blast stove, an inlet NOx content detection device, a hot blast stove preheater Heater, first desulfurization agent conveying switching device, second desulfurizing agent conveying switching device, denitrification reducing agent injection device and desulfurization, denitrification and dust removal device;

Wherein, the flue gas outlet of the hot blast stove is communicated with the inlet of the hot blast stove preheater through the original flue through the inlet NOx content detection device and the original flue cut-off valve in sequence; the first desulfurization agent conveying switching device is used for Spray the desulfurizer into the original flue;

The flue gas outlet of the hot blast stove is also communicated with the flue gas inlet of the desulfurization, denitrification and dust removal device through the inlet flue through the inlet flue cut-off valve, and the flue gas outlet of the desulfurization, denitration and dust removal device passes through the outlet flue through the outlet flue. The shut-off valve is communicated with the inlet of the hot blast stove preheater;

The second desulfurization agent conveying switching device is communicated with the desulfurizing agent injection port of the desulfurization, denitrification and dust removal device through a pipeline, so as to inject desulfurization agent into the desulfurization, denitrification and dust removal device through the second desulfurization agent conveying and switching device;

The denitration reducing agent injection device is used for injecting the denitration reducing agent into the desulfurization, denitration and dust removal device.

As a specific embodiment of the blast furnace hot blast furnace flue gas desulfurization and denitrification system of the present invention, the system further includes an interlocking control device, and the interlocking control device is respectively disconnected from the inlet NOx content detection device and the original flue. The valve, the inlet flue cut-off valve, the outlet flue cut-off valve, the first desulfurization agent conveying switching device, the second desulfurizing agent conveying switching device and the denitration reducing agent injection device are electrically connected.

As a specific embodiment of the above-mentioned blast furnace hot blast furnace flue gas desulfurization and denitrification system of the present invention, wherein the desulfurization agent injection port is located above the flue gas inlet, and is evenly distributed along the circumferential direction of the desulfurization, denitrification and dust removal device, Its number is 4-6.

As a specific embodiment of the blast furnace hot blast furnace flue gas desulfurization and denitrification system of the present invention, the desulfurization agent injection ports are uniformly distributed along the circumferential direction of the desulfurization, denitrification and dust removal device on the same plane.

As a specific embodiment of the above-mentioned blast furnace hot blast furnace flue gas desulfurization and denitrification system of the present invention, the desulfurization, denitrification and dust removal device is further provided with a dynamic disturbance element and a static disturbance element, wherein the dynamic disturbance element is arranged in the desulfurizer Above the injection port, and it is inserted into the desulfurization, denitrification and dust removal device in a manner of 10-30° from the plane where the desulfurizer is injected into the plane/the plane where the desulfurizer injection port is located;

The static disturbance element is arranged in the desulfurization, denitration and dust removal device, and is located above the dynamic disturbance element.

As a specific embodiment of the blast furnace hot blast furnace flue gas desulfurization and denitration system of the present invention, the dynamic disturbance element is arranged above the desulfurization agent injection port, and the distance between the dynamic disturbance element and the desulfurization agent injection port is 0.5m ;

The static disturbance element is located above the dynamic disturbance element, and the distance between the static disturbance element and the desulfurization agent injection port is 1.0-1.5m.

As a specific embodiment of the above-mentioned blast furnace hot blast furnace flue gas desulfurization and denitrification system of the present invention, the static disturbance element is fixedly arranged in the desulfurization, denitrification and dust removal device.

As a specific embodiment of the above-mentioned blast furnace hot blast furnace flue gas desulfurization and denitration system of the present invention, the dynamic disturbance element is an automatic stirrer.

As a specific embodiment of the above-mentioned blast furnace hot blast furnace flue gas desulfurization and denitrification system of the present invention, wherein the static disturbance element includes a plurality of steel folded plates arranged in parallel, and the plate length of the steel folded plates depends on the desulfurization, denitration and dust removal device. The width of the steel folded plate is 30-100mm, the distance between adjacent steel folded plates is 150-200mm, and the downward angle of the steel folded plate is 10-30°.

In the present invention, the downwardly folded position of each steel folded plate in the plurality of parallel steel folded plates may be the same or different, and may be adjusted within an appropriate range according to the actual working conditions and flow field conditions.

As a specific embodiment of the above-mentioned blast furnace hot blast furnace flue gas desulfurization and denitrification system of the present invention, wherein, the desulfurization, denitrification and dust removal device is further provided with a filter unit, which is arranged between the flue gas outlet and the static disturbance element, and the The filtration unit contains a denitration catalyst.

As a specific embodiment of the blast furnace hot blast furnace flue gas desulfurization and denitration system of the present invention, the filter unit includes a ceramic fiber filter tube, a filter bag or a filter cartridge.

The ceramic fiber filter tubes, filter bags or filter cartridges used in the present invention are all conventional equipment, which can be prepared by first dipping the denitration catalyst on the fibers, and then using the obtained fibers as raw materials according to the molding process disclosed in Chinese Patent CN113603502A into ceramic fiber filter tubes, filter bags or filter cartridges, etc.

In the present invention, the denitration catalyst is a conventional denitration catalyst used in the field, and can be reasonably selected according to the actual operation conditions on site, as long as the denitration purpose of the present application can be achieved.

As a specific embodiment of the above-mentioned blast furnace hot blast stove flue gas desulfurization and denitration system of the present invention, the system further includes a chimney, and the outlet of the hot blast stove preheater is connected to the chimney through a pipeline via a booster fan. The entrance is connected.

As a specific embodiment of the blast furnace hot blast furnace flue gas desulfurization and denitrification system of the present invention, the system further includes denitration reducing agent production and storage equipment for providing denitration reducing agent.

As a specific embodiment of the blast furnace hot blast furnace flue gas desulfurization and denitrification system of the present invention, the desulfurization, denitrification and dust removal device is further provided with an atomized water injection port, which is located above the desulfurization agent injection port, and is different from the desulphurization agent injection port. The distance between the injection ports of the desulfurizer is greater than 0.8m.

The present invention has no specific requirements on the shape of the desulfurization, denitration and dust removal device, and can be reasonably adjusted according to the actual working conditions on site. As in some embodiments of the present invention, the cross section of the desulfurization, denitration and dust removal device may be circular or square.

As a specific embodiment of the blast furnace hot blast furnace flue gas desulfurization and denitrification system of the present invention, the desulfurization, denitrification and dust removal device includes a plurality of (no less than two) chambers arranged in parallel.

The blast furnace hot blast stove flue gas desulfurization and denitration system provided by the present invention can be connected between the existing blast furnace hot blast stove and the hot blast stove preheater in a plug-in form, so as to realize the removal of nitrogen oxides, sulfur dioxide and particulate matter in the blast furnace hot blast stove flue gas. It can be highly integrated with the main system of the existing blast furnace hot blast stove, and is an ultra-low emission treatment system suitable for the technological characteristics of blast furnace hot blast stoves in iron and steel plants; Compared with the tail treatment technology of desulfurization and denitrification, the system provided by the invention has less equipment, shorter process and fewer failure points, thereby reducing the system failure rate and saving investment costs; the high flue gas temperature can ensure desulfurization and denitrification efficiency. The minimum limit will not be too low, making the system run more stable.

On the other hand, the present invention also provides a method for desulfurization and denitrification of blast furnace hot blast stove flue gas, wherein the method is realized by utilizing the above-mentioned blast furnace hot blast stove flue gas desulfurization and denitrification system, including the following steps:

Use the inlet NOx content detection device to detect the NOx content in the flue gas of the blast furnace hot blast stove. When the NOx content is lower than the set value, open the original flue cut-off valve and close the inlet flue cut-off valve and the outlet flue cut-off valve. The desulfurizing agent conveying switching device sprays the desulfurizing agent into the original flue to complete the desulfurization treatment of the flue gas in the original flue;

When the NOx content is not lower than the set value, open the inlet flue cut-off valve and the outlet flue cut-off valve and close the original flue cut-off valve, so that the flue gas from the blast furnace hot blast stove enters the desulfurization, denitrification and dust removal device through the inlet flue. The desulfurization agent and the denitration reducing agent are respectively injected into the desulfurization, denitration and dust removal device through the second desulfurization agent conveying switching device and the denitration reducing agent injection device, so that the blast furnace hot blast stove flue gas can be desulfurized, Dust removal and denitration treatment.

In the present invention, the set value of the NOx content can be reasonably determined according to the actual working conditions on site. As in some embodiments of the present invention, the set value of the NOx content is 150 mg/Nm ³ .

As a specific embodiment of the above-mentioned method for desulfurization and denitrification of blast furnace hot blast stove flue gas of the present invention, the temperature of the blast furnace hot blast stove flue gas is 260-450°C.

In the present invention, the flue gas of the blast furnace hot blast stove is not cooled by the preheater before entering the original flue or the desulfurization, denitrification and dust removal device, and its temperature is about 260-450°C. Ensure the high activity temperature conditions required by the dry desulfurizer (baking soda ≥ 140°C and slaked lime ≥ 250°C). To achieve the removal of SO ₂ in the flue gas. Due to the high temperature of the flue gas, the activity of the dry desulfurizer is high, so that the removal efficiency of SO2 is greater _than 98%.

As a specific embodiment of the above-mentioned blast furnace hot blast furnace flue gas desulfurization and denitration method of the present invention, the denitration temperature is 250-440°C.

As a specific embodiment of the blast furnace hot blast furnace flue gas desulfurization and denitration method of the present invention, the desulfurization agent includes baking soda or lime; the denitration reducing agent includes ammonia or carbon monoxide.

As a specific embodiment of the blast furnace hot blast furnace flue gas desulfurization and denitrification method of the present invention, the desulfurization agent is dry baking soda powder with a size of 600 mesh or more.

As a specific embodiment of the blast furnace hot blast furnace flue gas desulfurization and denitrification method of the present invention, the desulfurization agent is slaked lime powder with a purity of not less than 90%.

As a specific embodiment of the method for desulfurization and denitrification of blast furnace hot blast stove flue gas according to the present invention, when the SO ₂ content/concentration in the blast furnace hot blast stove flue gas exceeds 300 mg/Nm ³ , the method further includes: After the desulfurization agent is sprayed into the desulfurization, denitrification and dust removal device through the second desulfurization agent transportation switching device, atomized water is sprayed into the desulfurization, denitration and dust removal device to improve the desulfurization efficiency of the flue gas.

In the blast furnace hot blast furnace flue gas desulfurization and denitrification method provided by the present invention, when the NOx content is lower than the set value, only the flue gas needs to be desulfurized, and during the desulfurization process, the chain control device is used to control the original flue The shut-off valve, the inlet flue shut-off valve, the outlet flue shut-off valve and the first desulfurizing agent delivery switching device are turned on or off.

In the blast furnace hot blast stove flue gas desulfurization and denitrification method provided by the present invention, when the NOx content is not lower than the set value, desulfurization and denitration treatment of the flue gas needs to be carried out, wherein the desulfurizing agent is provided by the second desulfurizing agent conveying switching device. The power is injected into the desulfurization, denitrification and dust removal device through the desulfurization agent injection port on the surface of the desulfurization, denitration and dust removal device. Under the full stirring of the dynamic disturbance element, the dry powder of the desulfurization agent is fully contacted with the flue gas, and as the flue gas moves upward, it passes through the static disturbance element. The disturbance effect makes the gas-solid contact more uniform, and the removal of SO ₂ in the flue gas is realized in the above process;

The flue gas after desulfurization continues to be evenly mixed with the denitration reducing agent sprayed into the desulfurization, denitrification and dust removal device, and then continues to pass through the filter unit. During the process of passing through the filter unit, the flue gas after desulfurization mainly undergoes two purification processes: first , When the flue gas carrying particulate matter passes through the filter unit, the particulate matter is intercepted on the surface of the filter unit, and a powder cake layer (containing part of the desulfurizer) is formed on the outer surface of the filter unit. , to achieve the effect of prolonging the desulfurization reaction time and filtering dust with dust; secondly, under the catalytic action of the denitration catalyst contained in the filter unit, the denitration reducing agent reacts with the original NOx in the flue gas, and the reaction is under medium and high temperature conditions ( 250-440℃), it is well known in the industry that SCR denitration efficiency and denitration catalyst activity increase with the increase of reaction temperature, and it is not easy to be poisoned and deactivated by the influence of SO ₂ at high temperature. Compared with the low temperature denitration method, the efficiency of medium and high temperature denitration high, the risk of stable operation is greatly reduced, therefore, in the method provided by the present invention, after the denitration reaction is completed, more than 90% of NOx is removed;

In addition, in the present invention, the denitration catalyst with catalytic action is evenly distributed in the inner fibers of the filter unit, and the contact area with the flue gas is large, which can increase the residence time of the flue gas to about 1s, which is longer than the contact time in the traditional SCR (( 0.2-0.3s) increase 2-4 times;

The hot flue gas after desulfurization, dust removal and denitrification is completed and sent to the original hot blast stove preheater through the outlet flue, and heat exchange with gas or air, etc., and the clean flue gas cooled by the original hot blast stove preheater is passed through the booster fan. It is sent to the discharge chimney of the original hot blast stove for discharge up to the standard, and the resistance of the whole system is overcome by the booster fan installed at the end.

Compared with the prior art, the beneficial technical effects that the present invention can achieve include:

The blast furnace hot blast stove flue gas desulfurization and denitrification system and method provided by the invention can simultaneously realize the ultra-clean removal of SO ₂ and NOx in the blast furnace hot blast stove flue gas, and the SO ₂ concentration in the treated flue gas is less than 20mg/Nm ³ , NOx Concentration<30mg/Nm ³ ;

The blast furnace hot blast stove flue gas desulfurization and denitrification system and method provided by the present invention can make full use of the residual heat of the blast furnace hot blast stove flue gas itself. The loss is small, which can reduce the comprehensive energy consumption of flue gas desulfurization and denitrification; at the same time, there is no need to configure sub-system equipment such as heating furnace and GGH heat exchanger, and the fault point is greatly reduced, so that its impact on the main process can be greatly reduced;

The blast furnace hot blast stove flue gas desulfurization and denitrification system and method provided by the present invention adopts the scheme of co-treatment of sulfur nitrite and dust removal, which saves land occupation and investment;

The filter unit used in the blast furnace hot blast furnace flue gas desulfurization and denitration system and method provided by the present invention adopts hard filter materials, namely ceramic fiber filter tubes, filter bags or filter cartridges, which effectively solves the problem of the service life of the cloth bags used in the prior art. It is a major problem that affects the stable operation of the system; in addition, the long curvature of the pores in the filter unit can improve the contact time between the catalyst and the flue gas, so that the denitration efficiency can reach more than 90%;

The blast furnace hot blast stove flue gas desulfurization and denitrification system and method provided by the present invention can also open and close the denitration function of the system in real time according to the real-time monitoring data of the NOx content in the flue gas, so as to realize deep energy saving under the premise that the emission reaches the standard;

To sum up, the blast furnace hot blast stove flue gas desulfurization and denitrification system and method provided by the present invention can make full use of the own heat of the blast furnace hot blast stove flue gas, without the need for external heat sources and heating and heat exchange equipment; Before the preheater, high temperature desulfurization, dust removal and denitrification processes are adopted, which not only improves the desulfurization efficiency, but also meets the requirements of medium and high temperature denitration temperature. It belongs to the desulfurization and denitrification technology with low energy consumption, low investment and high stability.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the drawings in the following description are some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a blast furnace hot blast furnace flue gas desulfurization and denitrification system provided in Embodiment 1 of the present invention.

FIG. 2 is a schematic structural diagram of a static disturbance element used in Embodiment 1 of the present invention.

Description of main symbols:

1. Hot blast stove;

2. Inlet NOx content detection device;

3. Hot blast stove preheater;

4. The first desulfurizer conveying switching device;

5. The second desulfurizer conveying switching device;

6. Desulfurization, denitrification and dust removal device;

61. Flue gas inlet;

62. Flue gas outlet;

63. Desulfurizer spray inlet;

64. Dynamic disturbance element;

65. Static disturbance element;

650, steel folding plate;

66. Filter unit;

7. Denitration reducing agent injection device;

8. Chimney;

9. Chain control device;

10. The original flue;

11. The original flue cut-off valve;

12. Entrance flue;

13. Inlet flue cut-off valve;

14. Exit flue;

15. Outlet flue cut-off valve;

16. Desulfurizer storage tank;

17. Booster fan.

Detailed ways

It should be noted that the term "comprising" in the description and claims of the present invention and the above-mentioned drawings and any modifications thereof are intended to cover non-exclusive inclusion, for example, a process, method, method including a series of steps or units. A system, product or device is not necessarily limited to those steps or units expressly listed, but may include other steps or units not expressly listed or inherent to the process, method, product or device.

In the present invention, the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "middle", etc. is based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily used to better describe the invention and its embodiments, and are not intended to limit the fact that the indicated device, element or component must have a particular orientation, or be constructed and operated in a particular orientation.

In addition, some of the above-mentioned terms may be used to express other meanings besides orientation or positional relationship. For example, the term "on" may also be used to express a certain attachment or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present invention can be understood according to specific situations.

Furthermore, the terms "arranged", "connected" should be construed broadly. For example, "connection" may be a fixed connection, a detachable connection, or a unitary construction; it may be a mechanical connection, or an electrical connection; it may be a direct connection, or an indirect connection through an intermediary, or two devices, elements or Internal connectivity between components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

The "ranges" disclosed herein are given in the form of lower and upper limits. There can be one or more lower limits, and one or more upper limits, respectively. The given range is bounded by choosing a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges defined in this manner are combinable, ie any lower limit can be combined with any upper limit to form a range. For example, ranges of 60-120 and 80-110 are listed for certain parameters, with the understanding that ranges of 60-110 and 80-120 are also contemplated. Additionally, if the minimum range values listed are 1 and 2, and the maximum range values listed are 3, 4, and 5, the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.

In the present invention, unless otherwise stated, the numerical range "a-b" represents an abbreviated representation of any combination of real numbers between a and b, where both a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in the present invention, and "0-5" is just an abbreviated representation of the combination of these numerical values.

In the present invention, unless otherwise specified, all the embodiments and preferred embodiments mentioned in the present invention can be combined with each other to form new technical solutions.

In the present invention, unless otherwise specified, all the technical features and preferred features mentioned in the present invention can be combined with each other to form a new technical solution.

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments described below are a part of the embodiments of the present invention, but not all of the embodiments, and are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market.

Example 1

The present embodiment provides a blast furnace hot blast stove flue gas desulfurization and denitrification system, the schematic diagram of which is shown in FIG. 1 , and it can be seen from FIG. 1 that the blast furnace hot blast stove flue gas desulfurization and denitrification system includes:

Hot blast stove 1, inlet NOx content detection device 2, hot blast stove preheater 3, desulfurization agent storage tank 16, first desulfurization agent conveying switching device 4, second desulfurizing agent conveying switching device 5, desulfurization, denitrification and dust removal device 6, denitration reduction The agent injection device 7, the chimney 8 and the interlocking control device 9; wherein, the cross-sectional shape of the desulfurization, denitration and dust removal device 6 can be a circle or a square, which includes two parallel chambers;

Wherein, the flue gas outlet of the hot blast stove 1 is connected to the inlet of the hot blast stove preheater 3 through the original flue 10 through the inlet NOx content detection device 2 and the original flue cut-off valve 11 in sequence; the desulfurization agent storage tank 16 is communicated with the original flue 10 through the first desulfurizing agent conveying switching device 4 through the pipeline, so as to spray the desulfurizing agent into the original flue 10 through the first desulfurizing agent conveying switching device 4;

The flue gas outlet of the hot blast stove 1 also communicates with the flue gas inlet 61 of the desulfurization, denitration and dust removal device 6 through the inlet flue 12 and the inlet flue cut-off valve 13, and the flue gas outlet 62 of the desulfurization, denitration and dust removal device 6 passes through. The outlet flue 14 is communicated with the inlet of the hot blast stove preheater 3 via the outlet flue cut-off valve 15, and the outlet of the hot blast stove preheater 3 is communicated with the chimney 8 through a pipeline via a booster fan 17;

The desulfurization agent storage tank 16 is also communicated with the desulfurization agent injection port 63 of the desulfurization, denitrification and dust removal device 6 through the second desulfurization agent transportation switching device 5 through the pipeline, so as to pass the second desulfurization agent transportation switching device 5 to the desulfurization agent. The desulfurization agent is sprayed into the desulfurization, denitration and dust removal device 6;

The denitration reducing agent injection device 7 is used for injecting the denitration reducing agent into the desulfurization, denitration and dust removal device 6;

Wherein, the interlock control device 9 is respectively connected with the inlet NOx content detection device 2, the original flue cut-off valve 11, the inlet flue cut-off valve 13, the outlet flue cut-off valve 15, the first desulfurizer delivery switching device 4, the first The second desulfurizer conveying switching device 5 and the denitration reducing agent spraying device 7 are electrically connected;

Among them, the desulfurization, denitration and dust removal device 6 is further provided with a dynamic disturbance element 64, a static disturbance element 65 and a filter unit 66. The dynamic disturbance element 64 is arranged above the desulfurization agent injection port 63, and the distance from the desulfurization agent injection port 63 is 0.5 m, and it is inserted into the desulfurization, denitration and dust removal device 6 at an angle of 20° to the plane where the desulfurizer is sprayed into the plane/the plane where the desulfurizer is sprayed;

The static disturbance element 65 is fixedly arranged in the desulfurization, denitration and dust removal device 6, and is located above the dynamic disturbance element 64, and the distance from the desulfurization agent injection port 63 is 1.2m;

The dynamic disturbance element 64 is an automatic stirrer;

FIG. 2 shows the schematic diagram of the structure of the static disturbance element 65 and its arrangement in the desulfurization, denitrification and dust removal device 6 when the cross-sectional shapes of the desulfurization, denitration and dust removal device 6 are circular and square, respectively. From FIG. 2, it can be seen that It can be seen that it includes a plurality of parallel steel folded plates 650, the length of the steel folded plates 650 is 3.8m, the width is 80mm, the distance between adjacent steel folded plates is 150mm, the steel folded plates 650 The downward folded angle is 20°, and the downward folded position of each steel folded plate is the same;

The filter unit 66 is arranged between the flue gas outlet 62 and the static disturbance element 65, and the filter unit 65 contains a denitration catalyst, wherein the filter unit 66 is a ceramic fiber filter tube, which is passed through the ceramic fiber filter tube. First, the denitration catalyst is impregnated and coated on the fiber, and then the obtained fiber is used as the raw material to prepare according to the molding process disclosed in Chinese patent CN113603502A;

Wherein, the desulfurization agent injection ports 63 are located above the flue gas inlets 61, and are evenly distributed along the circumferential direction of the desulfurization, denitrification and dust removal device 7, and the number thereof is six.

Example 2

The present embodiment provides a method for desulfurization and denitrification of flue gas from a blast furnace hot blast stove, which is realized by using the blast furnace hot blast stove flue gas desulfurization and denitration system provided in Embodiment 1, wherein the method includes the following specific steps:

(1) Use the inlet NOx content detection device to detect the NOx content in the flue gas of the blast furnace hot blast stove (SO ₂ concentration is 200mg/Nm ³ and the temperature is 450°C), and the detected NOx content is 150mg/Nm ³ , which is the same as the set value ( 150mg/Nm ³ ) is the same, open the inlet flue cut-off valve and the outlet flue cut-off valve through the interlock control device, close the original flue cut-off valve, and slowly start the booster fan;

(2) The blast furnace hot blast stove flue gas enters the desulfurization, denitration and dust removal device through the inlet flue through the flue gas inlet, and at the same time, the second desulfurization agent conveying and switching device is activated through the interlock control device, and the desulfurizer (baking soda) is replaced by the second desulfurizer. The conveying switching device provides power, and is sprayed into the desulfurization, denitrification and dust removal device through the desulfurization agent spray port on the surface of the desulfurization, denitration and dust removal device. Under the full stirring of the dynamic disturbance element, the dry powder of the desulfurization agent and the flue gas are fully contacted and reacted, and with the upward movement of the flue gas, The gas-solid contact is made more uniform through the perturbation effect of the static perturbation element, and the removal of SO2 in the flue gas is achieved in the above process. After the reaction, the SO2 in the flue gas is removed by more _than 98%, and the outlet concentration is less _than 20mg /Nm ³ ;

(3) Start the denitration reducing agent injection device through the chain control device, and inject the denitration reducing agent (ammonia or carbon monoxide) into the desulfurization, denitration and dust removal device through the denitration reducing agent injection device, and the flue gas after desulfurization continues to move upward and The denitration reducing agent sprayed into the desulfurization, denitration and dust removal device is evenly mixed, and then continues to pass through the ceramic fiber filter tube. During the process of passing through the ceramic fiber filter tube, the flue gas after desulfurization mainly undergoes two purification processes: When the flue gas passes through the ceramic fiber filter tube, the particulate matter is intercepted on the surface of the ceramic fiber filter tube, and a powder cake layer (containing part of the desulfurizer) is formed on the outer surface of the ceramic fiber filter tube. The dust removal effect has achieved the effect of prolonging the desulfurization reaction time and filtering dust with dust; secondly, the denitration catalyst contained in the ceramic fiber filter tube (such as the medium and low temperature NH ₃ -SCR catalyst disclosed in Chinese Patent CN108435237A or a catalyst with a temperature of 250-440 ℃) Under the catalysis of high-activity commercial denitration catalyst), the denitration reducing agent reacts with the original NOx in the flue gas, and the reaction is carried out under medium and high temperature conditions (250-440 ° C). After the removal is completed, the NOx outlet concentration is less than 30mg/Nm ³ , the particulate matter concentration in the flue gas drops to 5-10mg/Nm ³ , and the desulfurization, dust removal and denitration treatment are completed;

(4) The flue gas after desulfurization, dust removal and denitration is completed, the temperature drop is controlled at 5-20 °C, and sent to the hot blast stove preheater through the outlet flue for heat exchange with gas or air, etc. The flue gas after heat exchange is increased by After the pressure blower is pressurized by about 3000-4000Pa, it is sent to the chimney of the original hot blast stove for discharge up to the standard.

Example 3

This embodiment uses the blast furnace hot blast stove flue gas desulfurization and denitrification system provided in Example 1 to perform desulfurization and denitrification on the flue gas of a blast furnace hot blast stove in a factory area, including: first, according to the connection relationship shown in FIG. Between the blast furnace hot blast stove and the hot blast stove preheater in a certain factory area, desulfurization and denitration are carried out according to the operation steps in Example 2;

Among them, the amount of flue gas discharged from a blast furnace hot blast stove in a certain factory area is 350000Nm ³ /h, the flue gas temperature is 300°C, and the SO ₂ concentration at the inlet of the desulfurization, denitrification and dust removal device is 150mg/Nm ³ , after desulfurization by the system provided in Example 1, The flue gas temperature before and after the desulfurization section in the desulfurization, denitrification and dust removal device does not change significantly, and the outlet SO ₂ concentration is less than 20mg/Nm ³ ;

The flue gas temperature before dust removal and denitrification is about 300°C, and no additional external thermal energy is required during the denitration process. After denitration, the particle concentration in the flue gas is <5mg/Nm ³ , and the NOx concentration is < 30mg/Nm ³ ; The temperature conditions used in the conventional post-installation desulfurization and denitrification technology are the post-installation medium-high temperature SCR of 150-280°C. In the embodiment of the present invention, there is no need to increase the investment of the flue gas heating furnace and the gas-gas heat exchanger, and each cubic meter of flue gas can be saved. The investment cost of about 70,000 yuan;

The flue gas temperature after desulfurization, dust removal and denitration treatment by the desulfurization, denitration and dust removal device drops by about 10°C, and the temperature is about 290°C. The treated flue gas is sent back to the hot blast stove preheater through the outlet flue. Compared with the conventional post-preheater SCR denitrification technology in the conventional post-preheater denitration technology, the denitrification is completed before the heat exchange of the flue gas, which can save the blast furnace gas consumption by about 5000Nm ³ /h (the calorific value of the blast furnace gas is 750Kcal). /Nm ³ ), which reduces the energy consumption of the system and improves the overall economic benefit of the system;

The flue gas at the outlet of the preheater of the hot blast stove is led to the chimney for discharge through the booster fan. The full pressure of the booster fan is 3500Pa. Since the flue gas desulfurization and denitrification system of the blast furnace hot blast stove does not need to be equipped with flue gas heating equipment and heat exchange equipment before and after denitration, the equipment is reduced. Resistance loss, making its pressure drop significantly lower than that of conventional post-desulfurization and denitrification technology (6500-8000Pa), which can reduce system power consumption;

Among them, the conventional post-desulfurization and denitrification technical process is the heat exchange of the heat exchanger (the main engine part) after the heat exchange of the flue gas and flue gas (depending on the requirements of the desulfurization situation) before the desulfurization and denitrification.

Compared with the prior art, the beneficial technical effects that the embodiments of the present invention can achieve include:

The blast furnace hot blast stove flue gas desulfurization and denitrification system and method provided by the embodiment of the present invention can simultaneously realize the ultra-clean removal of SO ₂ and NOx in the blast furnace hot blast stove flue gas, and the SO ₂ concentration in the treated flue gas is less than 20mg/Nm ³ , NOx concentration <30mg/Nm ³ ;

The blast furnace hot blast stove flue gas desulfurization and denitrification system and method provided by the embodiments of the present invention can make full use of the residual heat of the blast furnace hot blast stove flue gas itself, and compared with the post-SCR denitrification technology in the conventional post-desulphurization and denitrification technology, no additional heat is required to increase the temperature. The system resistance loss is small, which can reduce the comprehensive energy consumption of flue gas desulfurization and denitrification; at the same time, there is no need to configure sub-system equipment such as heating furnace and GGH heat exchanger, and the failure points are greatly reduced, thereby greatly reducing its impact on the main process;

The blast furnace hot blast stove flue gas desulfurization and denitrification system and method provided by the embodiment of the present invention adopts the scheme of synergistic treatment of sulfur nitrate and dust removal, which saves land occupation and investment;

The filter unit used in the blast furnace hot blast furnace flue gas desulfurization and denitrification system and method provided by the embodiment of the present invention adopts a hard filter material, that is, a ceramic fiber filter tube, a filter bag or a filter cartridge, which effectively solves the problem of the cloth bag used in the prior art. The short life of the filter is a major problem that affects the stable operation of the system; in addition, the long curvature of the pores in the filter unit can improve the contact time between the catalyst and the flue gas, so that the denitration efficiency can reach more than 90%;

The blast furnace hot blast stove flue gas desulfurization and denitrification system and method provided by the embodiment of the present invention can also open and close the denitrification function of the system in real time according to the real-time monitoring data of the NOx content in the flue gas, so as to realize deep energy saving on the premise that the emission reaches the standard;

To sum up, the system and method for desulfurization and denitrification of blast furnace hot blast stove flue gas provided by the embodiment of the present invention can make full use of the heat of blast furnace hot blast stove flue gas without external heat source and heating and heat exchange equipment; In front of the hot blast stove preheater, high temperature desulfurization, dust removal and denitration processes are adopted, which not only improves the desulfurization efficiency, but also meets the requirements of medium and high temperature denitration temperature. It belongs to the desulfurization and denitration technology with low energy consumption, low investment and high stability.

The above descriptions are only specific embodiments of the present invention, and cannot limit the scope of implementation of the invention. Therefore, the replacement of equivalent components, or the equivalent changes and modifications made according to the scope of the patent protection of the present invention should still be covered by this patent. category. In addition, in the present invention, the technical features and the technical features, the technical features and the technical inventions, and the technical inventions and the technical inventions can be freely combined and used.

Claims (13)

1. a blast furnace hot blast stove flue gas desulfurization and denitration system, is characterized in that, the system of described blast furnace hot blast stove flue gas desulfurization and denitrification comprises: hot blast stove, inlet NOx content detection device, hot blast stove preheater, the first desulfurization agent transport Switching device, second desulfurizing agent conveying switching device, denitration reducing agent injection device and desulfurization, denitrification and dust removal device; Wherein, the flue gas outlet of the hot blast stove is communicated with the inlet of the hot blast stove preheater through the original flue through the inlet NOx content detection device and the original flue cut-off valve in sequence; the first desulfurization agent conveying switching device is used for Spray the desulfurizer into the original flue; The flue gas outlet of the hot blast stove is also communicated with the flue gas inlet of the desulfurization, denitrification and dust removal device through the inlet flue through the inlet flue cut-off valve, and the flue gas outlet of the desulfurization, denitration and dust removal device passes through the outlet flue through the outlet flue. The shut-off valve is communicated with the inlet of the hot blast stove preheater; The second desulfurization agent conveying switching device is communicated with the desulfurizing agent injection port of the desulfurization, denitrification and dust removal device through a pipeline, so as to inject desulfurization agent into the desulfurization, denitrification and dust removal device through the second desulfurization agent conveying and switching device; The denitration reducing agent injection device is used for injecting the denitration reducing agent into the desulfurization, denitration and dust removal device. 2. The blast furnace hot blast stove flue gas desulfurization and denitration system according to claim 1, characterized in that the system further comprises an interlock control device, and the interlock control device is respectively cut off from the inlet NOx content detection device and the original flue. The valve, the inlet flue cut-off valve, the outlet flue cut-off valve, the first desulfurization agent conveying switching device, the second desulfurizing agent conveying switching device and the denitration reducing agent injection device are electrically connected. 3. The flue gas desulfurization and denitrification system of a blast furnace hot blast furnace according to claim 1 or 2, wherein the desulfurization agent injection port is located above the flue gas inlet, and is uniform along the circumferential direction of the desulfurization, denitrification and dust removal device distribution, the number of which is 4-6. 4 . The flue gas desulfurization and denitrification system of blast furnace hot blast stove according to claim 1 , wherein the desulfurization, denitrification and dust removal device is further provided with a dynamic disturbance element and a static disturbance element, wherein the dynamic disturbance element is arranged in the desulfurization agent. 5 . Above the injection port, and it is inserted into the desulfurization, denitrification and dust removal device in a manner of 10-30° from the injection plane of the desulfurizer; The static disturbance element is arranged in the desulfurization, denitration and dust removal device, and is located above the dynamic disturbance element. 5 . The flue gas desulfurization and denitration system of blast furnace hot blast stove according to claim 4 , wherein the dynamic disturbance element is an automatic stirrer. 6 . 6 . The flue gas desulfurization and denitrification system of a blast furnace hot blast furnace according to claim 4 , wherein the static disturbance element comprises a plurality of steel folded plates arranged in parallel, and the width of the steel folded plates is 30-100 mm. 7 . The distance between adjacent steel folded plates is 150-200mm, and the downwardly folded angle of the steel folded plates is 10-30°. 7. The blast furnace hot blast stove flue gas desulfurization and denitrification system according to any one of claims 1, 4-6, characterized in that, a filter unit is also provided in the desulfurization, denitrification and dust removal device, which is arranged between the flue gas outlet and the static Between the disturbance elements, and the filter unit contains a denitration catalyst. 8 . The flue gas desulfurization and denitration system of a blast furnace hot blast furnace according to claim 7 , wherein the filter unit comprises a ceramic fiber filter tube, a filter bag or a filter cartridge. 9 . 9. A blast furnace hot blast stove flue gas desulfurization and denitration method, characterized in that, the method is realized by utilizing the blast furnace hot blast stove flue gas desulfurization and denitration system described in any one of claims 1-8, comprising the following steps: Use the inlet NOx content detection device to detect the NOx content in the flue gas of the blast furnace hot blast stove. When the NOx content is lower than the set value, open the original flue cut-off valve and close the inlet flue cut-off valve and the outlet flue cut-off valve. The desulfurizing agent conveying switching device sprays the desulfurizing agent into the original flue to complete the desulfurization treatment of the flue gas in the original flue; When the NOx content is not lower than the set value, open the inlet flue cut-off valve and the outlet flue cut-off valve and close the original flue cut-off valve, so that the flue gas from the blast furnace hot blast stove enters the desulfurization, denitrification and dust removal device through the inlet flue. The desulfurization agent and the denitration reducing agent are respectively injected into the desulfurization, denitration and dust removal device through the second desulfurization agent conveying switching device and the denitration reducing agent injection device, so that the blast furnace hot blast stove flue gas can be desulfurized, Dust removal and denitration treatment. 10 . The method for desulfurization and denitration of flue gas from a blast furnace hot blast stove according to claim 9 , wherein the temperature of the blast furnace hot blast stove flue gas is 260-450° C. 11 . 11. The method for desulfurization and denitrification of blast furnace hot blast stove flue gas according to claim 9 or 10, wherein the temperature of denitration is 250-440°C. 12. The method for desulfurization and denitrification of blast furnace hot blast stove flue gas according to claim 9 or 10, wherein the desulfurization agent comprises baking soda or lime; the denitration reducing agent comprises ammonia gas or carbon monoxide. 13. The method for desulfurization and denitrification of blast furnace hot blast stove flue gas according to claim 9 or ₁₀ , wherein when the SO content/concentration in the blast furnace hot blast stove flue gas exceeds 300 mg/Nm ³ , the method also It includes spraying the desulfurization agent into the desulfurization, denitrification and dust removal device through the second desulfurization agent conveying switching device, and then spraying atomized water into the desulfurization, denitrification and dust removal device.

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