CN111545053A - Vortex type soot blowing assembly, SCR reaction device comprising same and method - Google Patents

Abstract

The invention provides a vortex type soot blowing assembly, an SCR reaction device and method including the same. It is inclined and arranged on the outer wall of the casing in the same direction as the outer circumference of the casing. The blowing pipe is externally connected to a compressed air source, and the compressed air is sprayed into the inside of the casing through the blowing pipe to form an airflow vortex to blow the dust-prone areas inside the casing. Clean the ashes. The vortex type soot blowing assembly provided by the present invention provides compressed air through a compressed air source, and the compressed air is blown into the casing at a certain angle through the blowing pipe, forming an orderly vortex air flow in the area where the casing is prone to dust accumulation, so as to realize Jet cleaning of dust deposits.

Description

A vortex type soot blowing assembly, SCR reaction device and method including the same

technical field

The invention belongs to the technical field of flue gas treatment, and relates to a soot blowing assembly, an SCR reaction device and method including the same, and in particular to a vortex soot blowing assembly, an SCR reaction device and method including the same.

Background technique

The emission of nitrogen oxides in the cement industry is 1.706 million tons, accounting for about 10% of the national total, and it is the second largest industrial emission source after the power industry. China pays more and more attention to the control of NO _x in the cement industry. The emission standard of nitrogen oxides in flue gas is 400mg/Nm ³ , and 320mg/Nm ³ in special areas. As the emission reduction standards of nitrogen oxides become stricter year by year, the research on denitration technology in the cement industry has been accelerated. The selective catalytic reduction (SCR) denitration efficiency is high, reaching 70% to 90%. The layout is flexible and the technology is mature. It is widely used in the cement industry. Has huge potential.

The core of SCR denitration technology lies in efficient catalysts. However, due to the problem of fouling, the catalyst is often blocked and worn, which affects the denitration efficiency of the SCR reactor. Therefore, a soot blowing system is often installed above the catalyst. However, in the case of extremely high dust, the reactor is It is easy to cause ash accumulation at the bottom. When the ash accumulation at the bottom of the reactor is serious, it may block the reactor and affect the normal operation of the reactor.

An important indicator of SCR denitration technology is denitration efficiency, so it is very necessary to study the uniformity of velocity distribution caused by the arrangement of equipment in the reactor. The uniformity of the flow field distribution affects the degree of reaction between the flue gas and the catalyst, and ultimately determines the denitration efficiency. Generally, the arrangement of the deflector is arc-straight deflector, which will inevitably lead to a small speed measured in the reactor, resulting in a low uniformity of the speed, which affects the denitration efficiency.

CN205164496U discloses a denitration reactor system of double soot blowing devices, comprising a denitration reactor, a number of soot blower assemblies are installed in the denitration reactor, and the soot blower assemblies include an ultrasonic soot blower and a steam soot blower. The positions of the soot blower and the steam soot blower are opposite; the steam soot blower is connected with a steam pipeline, and the ultrasonic soot blower is connected with a control valve. In the utility model, in order to remove the ash in the catalyst and prevent the catalyst from blocking the ash, each reactor is provided with an ultrasonic soot blower and a steam soot blower for soot blowing, and the double soot blower design is more efficient than the single soot blower design. It can reduce the pressure drop of the system and improve the efficiency and life of the catalyst. However, this patent is only for soot blowing at the catalyst bed, and does not involve soot blowing at the bottom of the reactor.

CN109821414A discloses an anti-fouling device for a denitrification reactor, comprising: an air blowing device; a horizontal section purging pipeline, one end of which is communicated with the air outlet of the air blowing device; and a horizontal section purging device, which is connected to the horizontal section The other end of the scavenging pipeline is connected, and is used for purging the flue of the inlet horizontal section of the denitration reactor. The denitrification reactor ash prevention device provided by the present invention provides compressed air through an air blowing device, and the compressed air is transported to the horizontal section purging device through the horizontal section purging pipeline, and sprayed on the inlet horizontal section flue. The ash deposited in the flue of the horizontal section of the inlet is blown away under the action of the air flow, and is discharged from the denitration reactor with the flue gas. This solution reduces the problem of excessive load-bearing and damage to the flue caused by the accumulation of ash in the horizontal section of the inlet, but it is mainly for purging the horizontal pipe at the outlet of the reactor, and has no effect on the purging of the vertical wall of the reactor below the catalyst. big.

It can be seen from this that the currently known prior art cannot solve the problem of fouling at the bottom of the SCR reaction device, so it is urgent to design a new type of soot blowing component for the SCR reaction device to effectively solve the problem of fouling. .

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a scroll type soot blowing assembly, an SCR reaction device and method including the same, and the scroll type soot blowing assembly provided by the present invention provides compressed air through a compressed air source, The compressed air is blown into the shell at a certain angle through the injection pipe, and an orderly vortex air flow is formed in the area where the shell is prone to fouling, so as to realize the blowing and cleaning of fouling.

For this purpose, the present invention adopts the following technical solutions:

In a first aspect, the present invention provides a vortex type soot blowing assembly for preventing dust accumulation, the vortex type soot blowing assembly includes at least three blowing pipes arranged along the circumferential direction of the casing, and the blowing pipes are arranged along the circumferential direction of the casing. The outer circumference of the casing is inclined in the same direction on the outer wall of the casing. The blowing pipe is externally connected to a compressed air source. The compressed air is sprayed into the casing through the blowing pipe to form an airflow vortex to blow and clean the dust-prone areas inside the casing. Ash.

The vortex type soot blowing assembly provided by the present invention provides compressed air through a compressed air source, and the compressed air is blown into the casing at a certain angle through the blowing pipe, forming an orderly vortex air flow in the area where the casing is prone to dust accumulation, so as to realize Blast cleaning of fouling.

It should be noted:

(1) The soot blowing assembly provided by the present invention has strong adaptability to the outer shape of the casing. In other words, the present invention does not make special requirements or specific restrictions on the cross-sectional shape of the casing, and any casing of any shape existing on the market is suitable for this application. The scroll type soot blowing assembly provided by the invention;

(2) The present invention also does not make specific requirements or special restrictions on the installation position of the scroll type soot blowing assembly on the casing. On the premise of satisfying the layout conditions, it can be installed in the area where the casing is prone to fouling. According to the changes in the usage scenarios and application fields, those skilled in the art can also adjust the installation position of the soot blowing assembly in a timely manner, which is inconvenient to be limited in the present invention;

(3) The present invention does not have special requirements and specific limitations on the number of blowing pipes. Those skilled in the art can arrange more or less blowing pipes according to the limitation of the amount of ash, usage scenarios and the size of the casing. There should be at least three groups of vortex airflow formed inside;

(4) The blowing pipe provided by the present invention can be installed obliquely on the outer wall of the casing on the horizontal plane, and the vortex air flow formed thereby is a plane vortex air flow, and the blowing pipe can also be inclined on the vertical plane and installed on the outer wall surface of the casing (horizontal plane). It should also be installed along the same inclined direction to ensure the formation of vortex airflow), that is, the compressed air is injected into the housing obliquely upward or downward through the injection pipe, and the vortex airflow formed thereby is a three-dimensional vortex airflow. The personnel can choose different inclination methods according to the actual production needs, but it must be ensured that the injection pipes are inclined in the same direction, otherwise the internal air flow will be turbulent and will not be able to form eddy currents.

As a preferred technical solution of the present invention, the blowing pipe is arranged horizontally along the circumferential direction of the casing, the blowing pipe is inclined and arranged on the outer wall surface of the casing along the same inclined direction on the horizontal plane, and the compressed air is sprayed into the casing through the blowing pipe. The inside of the casing forms a vortex of airflow on the horizontal plane.

Preferably, the cross-section of the casing is polygonal, and at least one blowing pipe is respectively provided on the outer wall of each side of the casing.

Preferably, in the horizontal plane, the angle between the blowing pipe and the outer wall of the casing is 15-45°, and the compressed air is injected into the casing at an oblique angle of 15-45°, for example, it can be 15°, 17°, 19° °, 21°, 23°, 25°, 27°, 29°, 31°, 33°, 35°, 37°, 39°, 41°, 43° or 45°, but not limited to the recited values, The same applies to other non-recited values within this numerical range.

Preferably, the cross section of the casing is circular, and at least three blowing pipes are equidistantly arranged on the outer wall of the casing.

Preferably, in the horizontal plane, the angle between the tangent of the point where the blowing pipe and the casing meet and the blowing pipe is 15-45°, and the compressed air is injected into the casing at an oblique angle of 15-45°, for example, it can be is 15°, 17°, 19°, 21°, 23°, 25°, 27°, 29°, 31°, 33°, 35°, 37°, 39°, 41°, 43° or 45°, but Not limited to the recited values, other non-recited values within the range of values apply equally.

In a second aspect, the present invention provides an SCR reaction device provided with the soot blowing assembly as described in the first aspect. The SCR reaction device includes a vertical casing and at least one laterally disposed inside the vertical casing. layer catalyst layer.

The bottom of the vertical casing is provided with the soot blowing assembly described in the first aspect.

In the present application, a vortex type soot blowing component is arranged under the catalyst layer, and the vortex cyclone generated by the vortex type soot blower component inside the shell increases the air disturbance at the bottom of the catalyst layer, and effectively solves the problem of smoke caused by soot accumulation in the flue. Excessive channel load and blockage of the bottom pipeline ensure the normal operation of the SCR reaction device.

It should be noted that, in order to fully realize the SCR denitration process, the entire SCR denitration system, in addition to the SCR reaction device defined in the present invention, must also include general equipment such as a reducing agent storage tank and a reducing agent injection device. The reducing agent injection device is arranged in the SCR. On the flue gas inlet pipeline of the reaction device, the reducing agent injection device is connected to an external reducing agent storage tank. When the flue gas flows through the flue gas inlet pipeline, it contacts and mixes with the reducing agent injected by the reducing agent injection device and then passes into the SCR reaction device. However, it can also be understood that the above contents are known to those skilled in the art, and are necessary equipment in the SCR denitration system disclosed in the prior art. The improvement of the internal structure, as for the remaining equipment connected to the SCR denitration device, such as the above-mentioned reducing agent injection device, reducing agent storage tank, etc., do not belong to the scope of protection and disclosure of the present invention, even if the present invention does not apply to the entire SCR denitration system. The structure is described in detail, and those skilled in the art can also restore the entire SCR denitration system according to the technical knowledge they have mastered.

As a preferred technical solution of the present invention, the top inlet of the vertical casing is provided with a horizontal variable diameter inlet flue, and the bottom outlet of the vertical casing is provided with a horizontal variable diameter outlet flue, The flue gas enters the vertical casing from the inlet flue along the horizontal direction, passes through the catalyst layer in sequence from top to bottom, and is discharged from the outlet flue along the horizontal direction.

Preferably, at least two sets of deflectors are arranged inside the turning flue where the inlet flue is connected to the vertical casing, and the deflectors are used to change the flow direction of the flue gas entering the inlet flue.

Preferably, the deflector is an arc-straight deflector with a segmented structure.

Preferably, at least one layer of rectifying grille is provided on the top of the vertical housing.

Preferably, the rectifying grids are arranged at equal intervals.

Preferably, the distance between two adjacent rectifying grids is controlled within 40-100mm, for example, it can be 40mm, 50mm, 60mm, 70mm, 80mm, 90mm or 100mm, but it is not limited to the listed values, within the range of the values Other non-recited values also apply.

Preferably, the soot blowing assembly is provided on the outer wall surface of the vertical casing above the outlet flue;

Preferably, the outlet flue is provided with a particulate matter detection device, and the particulate matter detection device is used to detect the concentration of particulate matter in the exhaust smoke from the outlet flue.

As a preferred technical solution of the present invention, the deflector is divided into an inner deflector and an outer deflector, and the inner deflector is arranged on the turning flue where the inlet flue and the vertical casing are butted On the inner side, the outer deflector is arranged on the outside of the turning flue where the inlet flue and the vertical casing are butted, and the inner deflector and the outer deflector are radially distributed along the flue gas flow direction.

Preferably, the inner side deflector includes a butt-jointed inner arc-shaped deflector and an inner straight deflector along the flue gas flow direction, and the inner arc-shaped deflector extends toward the inside of the turning flue to form an inner straight deflector plate.

Preferably, the included angle between the inner straight deflector and the vertical direction is 5° to 15°, such as 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12° , 13°, 14° or 15°, but are not limited to the recited values, and other unrecited values within this range of values are equally applicable.

Preferably, the outer baffle plate includes a butt-jointed outer arc-shaped baffle plate and an outer straight baffle plate along the flue gas flow direction, and the outer arc-shaped baffle plate extends in the vertical direction to form an outer straight baffle plate .

In the present invention, on the outside of the inlet flue, a plurality of arc-shaped guide plates are connected with the vertical downward straight guide plates, and on the inner side, a plurality of arc-shaped guide plates are connected with the straight guide plates with an angle of 5-15°, The distribution uniformity and speed uniformity of the flue gas entering the inlet flue are effectively improved through the special structure of the deflector.

It should be noted that the present invention does not impose specific requirements or special restrictions on the number of inner and outer baffles. Those skilled in the art can make appropriate adjustments according to the cross-sectional area of the inlet flue and the amount of flue gas to be treated, but at least Set up an inner deflector and an outer deflector, and through the radial distribution of the inner deflector and the outer deflector, the cross-sectional area of the flue formed between the two gradually increases along the flue gas flow direction, thereby improving the smoke flow. uniformity of gas distribution.

As a preferred technical solution of the present invention, a soot blowing device is provided above each catalyst layer, and the soot blowing device is used to spray and clean the catalyst layer.

Preferably, the compressed air inlets of the soot blowing device are combined into one channel and then connected to the compressed air source through the compressed air main pipe, and the compressed air source respectively provides compressed air to different soot blowing devices through the compressed air main pipe.

Preferably, a heating device is provided on the compressed air main pipe, and the compressed air provided by the compressed air source is heated by the heating device and distributed to different soot blowing devices.

Preferably, the soot blowing device and the blowing pipe use different compressed air sources respectively or share the same compressed air source, further preferably, the soot blowing device and the blowing pipe share the same compressed air source air source.

Preferably, a compressed air branch pipe is arranged on the main compressed air main pipe, the outlet end of the compressed air branch pipe is connected to the blowing pipe, and the compressed air provided by the compressed air source is heated by the heating device and then flows into the blowing pipe pair. The dust accumulation area at the bottom of the vertical shell is sprayed to clean the dust.

Preferably, the compressed air branch pipe is provided with a regulating valve.

In the present invention, a heating device is arranged at the front end of the compressed air flow of the soot blowing device and the vortex soot blowing assembly, and the compressed air is preheated and passed into the soot blowing device and the vortex soot blowing assembly to reduce the temperature difference between the flue gas and the compressed air.

As a preferred technical solution of the present invention, the catalyst used in the catalyst layer includes a carrier and active components and auxiliary components supported on the carrier.

Preferably, the carrier comprises one or a combination of at least two of TiO ₂ , molecular sieve, mesoporous alumina or montmorillonite.

Preferably, the active ingredient includes V ₂ O ₅ .

Preferably, the auxiliary component includes WO ₃ .

As a preferred technical solution of the present invention, a first catalyst layer, a second catalyst layer and a third catalyst layer are arranged in the vertical casing at intervals along the flue gas flow direction.

In a third aspect, the present invention provides a method for denitrifying flue gas using the SCR reaction device described in the second aspect, the method comprising:

The flue gas enters the SCR reaction device, passes through the catalyst layer from bottom to top, and undergoes a selective catalytic oxidation reaction with the reducing agent under the action of the catalyst to remove NO _x in the flue gas. The internal dust accumulation area is sprayed to clean the dust.

As a preferred technical solution of the present invention, the method specifically comprises the following steps:

(I) The flue gas enters the SCR reaction device, passes through the catalyst layer from bottom to top, and undergoes a selective catalytic oxidation reaction with the reducing agent under the action of the catalyst to remove NO _x in the flue gas;

(II) The compressed air provided by the compressed air source is preheated by the heating device and distributed to different soot blowing devices, and the catalyst layer is regularly sprayed to clean the soot;

(III) The compressed air provided by the compressed air source is preheated by the heating device and then passed into the blowing pipe. After the compressed air is sprayed into the vertical casing, an airflow vortex on the horizontal plane is formed, which realizes the protection of the dust-prone area at the bottom of the vertical casing. Blow out dust.

Preferably, in step (II), the soot blowing frequency of the soot blowing device on the catalyst layer is 1 to 3 times a day, for example, it can be once a day, twice a day or three times a day, but it is not limited to the listed value, other non-recited values within this value range also apply.

Preferably, when the concentration of particulate matter in the flue gas discharged from the outlet flue is greater than 20 mg/Nm ³ , the regulating valve is opened, and step (III) is performed.

Exemplarily, the SCR reaction device provided by the present invention is used to perform SCR denitrification treatment on the flue gas of the cement kiln tail, and the treatment process specifically includes the following steps:

(1) In the early stage of operation of the SCR reaction device, the flue gas discharged from the kiln tail flue of the cement kiln flows into the inlet flue of the SCR denitrification device, passes through the guide plate to improve the uniformity of the distribution of the flue gas, and then passes through the rectification grille. The speed uniformity of the flue gas is improved, and the nitrogen oxides and the reducing agent (ammonia) in the flue gas react on the catalyst layer to generate nitrogen and water, and the flue gas is purified. After the catalyst layer and the ^third catalyst layer are discharged from the outlet flue, the particulate matter detection device detects the concentration of particulate matter in the exhaust flue gas from the outlet flue. Less soot deposits at the bottom, close the regulating valve, stop the soot blowing components, reduce the use of compressed air and heating devices, and reduce operating costs. After running for a period of time, the particulate matter in the flue gas blocks the catalyst layer. The compressed air provided by the compressed air source is preheated by the heating device and then passes into the soot blowing device, and blows the opposite catalyst layer below to remove dust to reduce the clogging of the catalyst layer. , reduce the temperature difference between the compressed air and the flue gas by preheating, and the soot blowing frequency of the soot blowing device on the catalyst layer is 1 to 3 times a day.

(2) During the later operation, the particulate matter detection device detected that the outlet particulate matter concentration in the exhaust flue gas was greater than 20mg/Nm ³ , indicating that the inner wall and bottom of the SCR reaction device had serious dust accumulation at this time, and the regulating valve was opened at this time. , the opening of the regulating valve is adjusted to half the size, the compressed air provided by the compressed air source is preheated by the heating device and sent to the scroll soot blowing component, and the preheated compressed air is injected into the vertical shell at a 30° inclination through the injection pipe In the ash accumulation area at the bottom of the body, the compressed air forms a vortex air flow on the horizontal plane at the bottom of the vertical casing to realize the cleaning of the ash accumulation at the bottom.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The scroll type soot blowing assembly provided by the present invention provides compressed air through a compressed air source, and the compressed air is blown into the casing at a certain angle through the injection pipe, and an orderly vortex is formed in the area where the casing is prone to fouling. Air flow to achieve blowing and cleaning of dust deposits.

(2) In the present invention, on the outside of the inlet flue, several arc-shaped baffles are connected to the vertical downward straight baffles, and on the inner side are several arc-shaped baffles and the straight baffles with an angle of 5 to 15° Connected to each other, the distribution uniformity and speed uniformity of the flue gas entering the inlet flue are effectively improved through the special structure of the deflector.

(3) In the present application, a vortex type soot blowing assembly is arranged below the catalyst layer, and the vortex cyclone generated by the vortex type soot blower assembly inside the casing increases the air disturbance at the bottom of the catalyst layer, effectively solving the problem of soot accumulation in the flue The resulting flue load is too large and the bottom pipe is blocked.

(4) In the present invention, a heating device is arranged at the front end of the compressed air flow of the soot blowing device and the vortex soot blowing assembly, and the compressed air is preheated and passed into the soot blowing device and the vortex soot blowing assembly to reduce the gap between the flue gas and the compressed air. temperature difference.

Description of drawings

1 is a schematic structural diagram of a scroll-type sootblower assembly for a polygonal section shell provided by a specific embodiment of the present invention;

2 is a schematic structural diagram of a scroll-type sootblower assembly for a casing with a circular section provided by a specific embodiment of the present invention;

FIG. 3 is a schematic structural diagram of an SCR reaction device provided by a specific embodiment of the present invention.

Wherein, 1-vertical shell; 2-inlet flue; 3-outlet flue; 4-first catalyst layer; 5-second catalyst layer; 6-third catalyst layer; 7-first soot blowing device; 8-Second soot blowing device; 9-Third soot blowing device; 10-Compressed air main pipe; 11-Heating device; 12-Compressed air source; 13-Compressed air branch pipe; 14-Regulating valve; 16-outer deflector; 17-inner deflector; 18-particulate detection device; 19-spray pipe.

Detailed ways

It should be understood that in the description of the present invention, the terms "center", "portrait", "horizontal", "top", "bottom", "front", "rear", "left", "right", " The orientation or positional relationship indicated by vertical, horizontal, top, bottom, inner, outer, etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and The description is simplified rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention. In addition, the terms "first", "second", etc. are used for descriptive purposes only, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first", "second", etc., may expressly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

It should be noted that, in the description of the present invention, unless otherwise expressly specified and limited, the terms "arranged", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; it can be mechanical connection or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

The technical solutions of the present invention are further described below with reference to the accompanying drawings and through specific embodiments.

In a specific embodiment, the present invention provides a vortex type sootblower assembly 15. As shown in FIG. 1 or FIG. 2 , the vortex type sootblower assembly 15 includes at least three A blowing pipe 19 is provided, and the blowing pipe 19 is inclined and arranged on the outer wall of the casing along the same direction of the outer circumference of the casing. The internal dust accumulation area is sprayed to clean the dust.

The blowing pipe 19 is arranged horizontally along the circumferential direction of the casing, and the blowing pipe 19 is arranged on the outer wall of the casing along the same inclined direction on the horizontal plane.

The soot blowing assembly 15 provided by the present invention has strong adaptability, and has lower requirements on the cross-sectional shape of the casing. Any shape casing existing on the market today is suitable for the scroll type soot blowing assembly 15 provided by the present invention. A possible applicable cross-sectional shape of the casing is: as shown in Figure 1, when the cross-section of the casing is square, at least one blowing pipe 19 is respectively provided on the outer wall of each side of the casing. In the horizontal plane, the blowing pipe 19 The included angle with the outer wall of the casing is 15-45°, and the compressed air is injected into the casing at an oblique angle of 15-45°. As shown in FIG. 2 , when the cross-section of the casing is circular, at least three blowing pipes 19 are equidistantly arranged on the outer wall of the casing. The included angle is 15-45°, and the compressed air is sprayed into the casing at an oblique angle of 15-45°.

In another specific embodiment, the present invention provides an SCR reaction device provided with the above-mentioned soot blowing assembly 15 inside. As shown in FIG. 3 , the SCR reaction device includes a vertical casing 1 and a vertical At least one catalyst layer inside the vertical casing 1, as shown in Figure 3, the vertical casing 1 is provided with a first catalyst layer 4, a second catalyst layer 5 and a third catalyst layer 6 at intervals along the flue gas flow direction. The above-mentioned soot blowing assembly 15 is arranged at the bottom of the type housing 1 .

The top inlet of the vertical housing 1 is provided with a horizontal variable diameter inlet flue 2, and the bottom outlet of the vertical housing 1 is provided with a horizontal variable diameter outlet flue 3, and the flue gas enters the vertical housing from the inlet flue 2 along the horizontal direction. The casing 1 passes through the catalyst layer in sequence from top to bottom and is discharged from the outlet flue 3 along the horizontal direction.

At least two sets of deflectors are arranged inside the turning flue where the inlet flue 2 is docked with the vertical casing 1 , and the deflectors are used to change the flow direction of the flue gas entering the inlet flue 2 . The deflector is an arc-straight deflector with a segmented structure. The top of the vertical housing 1 is provided with at least one layer of rectifying grids, the rectifying grids are arranged at equal intervals, and the distance between two adjacent rectifying grids is controlled at 40-100 mm. The above-mentioned soot blowing assembly 15 is arranged on the outer wall surface of the vertical casing 1 above the outlet flue 3 , and a particle detection device 18 is arranged on the outlet flue 3 .

The deflector is divided into an inner deflector 17 and an outer deflector 16. The inner deflector 17 is arranged on the inner side of the turning flue where the inlet flue 2 and the vertical casing 1 are butted, and the outer deflector 16 is arranged on the inlet flue. On the outside of the turning flue where the flue 2 is connected to the vertical casing 1, the inner baffle 17 and the outer baffle 16 are radially distributed along the flue gas flow direction. The inner baffle 17 includes abutted inner arc baffle and inner straight baffle along the flue gas flow direction, the inner arc baffle extends to the inside of the turning flue to form an inner straight baffle, and the inner straight baffle The included angle in the vertical direction is 5 to 15°. The outer baffle 16 includes abutted outer arc baffle and outer straight baffle along the flue gas flow direction, and the outer arc baffle extends in the vertical direction to form an outer straight baffle.

A soot blowing device is arranged above each catalyst layer, and the soot blowing device is used to spray and clean the catalyst layer. Specifically, as shown in FIG. 3 , a first soot blower 7 is arranged above the first catalyst layer 4 , a second soot blower 8 is arranged above the second catalyst layer 5 , and a third soot blower 9 is arranged above the third catalyst layer 6 . , the compressed air inlets of the soot blowing devices of each layer are combined into one channel and then connected to the compressed air source 12 through the compressed air main pipe 10 , and the compressed air source 12 respectively provides compressed air to different soot blowing devices through the compressed air main pipe 10 . The compressed air main pipe 10 is provided with a heating device 11, and the compressed air provided by the compressed air source 12 is heated by the heating device 11 and distributed to different soot blowing devices.

The soot blowing device and the blowing pipe 19 share the same compressed air source 12 , a compressed air branch pipe 13 is arranged on the compressed air main pipe 10 , the outlet end of the compressed air branch pipe 13 is connected to the blowing pipe 19 , and the compressed air source 12 The provided compressed air is heated by the heating device 11 and then passed into the blowing pipe 19 to blow and clean the dust accumulation area at the bottom of the vertical casing 1 . The compressed air branch pipe 13 is provided with a regulating valve 14 .

The catalyst used in the catalyst layer includes a carrier and active components and auxiliary components supported on the carrier. The carrier can be selected from one or a combination of at least two of TiO ₂ , molecular sieve, mesoporous alumina or montmorillonite. The active components include V ₂ O ₅ and auxiliary components include WO ₃ .

In another specific embodiment, the present invention provides a denitrification treatment of flue gas using the above-mentioned SCR reaction device, and the treatment process specifically includes the following steps:

(I) The flue gas enters the SCR reaction device, passes through the catalyst layer from bottom to top, and undergoes a selective catalytic oxidation reaction with the reducing agent under the action of the catalyst to remove NO _x in the flue gas;

(II) The compressed air provided by the compressed air source 12 is preheated by the heating device 11 and distributed to different soot blowing devices, and the catalyst layer is periodically blown to clean the soot. 3 times;

(III) When the concentration of particulate matter in the flue gas discharged from the outlet flue 3 is greater than 20 mg/Nm ³ , the regulating valve 14 is opened, and the compressed air provided by the compressed air source 12 is preheated by the heating device 11 and passed into the blowing pipe 19, After the compressed air is injected into the vertical casing 1 , an airflow vortex on the horizontal plane is formed, so as to realize the blowing and cleaning of the dust-prone area at the bottom of the vertical casing 1 .

Example 1

This embodiment provides an SCR reaction device. As shown in FIG. 3 , the SCR reaction device includes a vertical casing 1 and three catalyst layers laterally arranged inside the vertical casing 1 . A first catalyst layer 4 , a second catalyst layer 5 and a third catalyst layer 6 are arranged at intervals in the gas flow direction. The catalyst used in the three-layer catalyst layer includes a carrier, active components and auxiliary components supported on the carrier, the carrier is TiO ₂ , the active component is V ₂ O ₅ , and the auxiliary component is WO ₃ .

The top inlet of the vertical housing 1 is provided with a horizontal variable diameter inlet flue 2, and the bottom outlet of the vertical housing 1 is provided with a horizontal variable diameter outlet flue 3, and the flue gas enters the vertical housing from the inlet flue 2 along the horizontal direction. The casing 1 passes through the first catalyst layer 4 , the second catalyst layer 5 and the third catalyst layer 6 sequentially from top to bottom and then is discharged from the outlet flue 3 along the horizontal direction.

Inside the turning flue where the inlet flue 2 and the vertical shell 1 are connected, there are five groups of arc-straight deflectors with segmented structure. 17 and 3 sets of outer baffles 16, 2 sets of inner baffles 17 are arranged parallel to the inside of the turning flue where the inlet flue 2 and the vertical casing 1 are butted, and 3 sets of outer baffles 16 are arranged parallel to the inlet flue 2. On the outside of the turning flue butted with the vertical casing 1, the inner baffle 17 and the outer baffle 16 are radially distributed along the flue gas flow direction. The inner baffle 17 includes abutted inner arc baffle and inner straight baffle along the flue gas flow direction, the inner arc baffle extends to the inside of the turning flue to form an inner straight baffle, and the inner straight baffle The included angle in the vertical direction is 5°. The outer baffle 16 includes abutted outer arc baffle and outer straight baffle along the flue gas flow direction, and the outer arc baffle extends in the vertical direction to form an outer straight baffle.

The top of the vertical housing 1 is provided with four layers of rectifying grids, the rectifying grids are arranged at equal intervals, and the distance between two adjacent rectifying grids is controlled at 40mm.

The outer wall surface of the bottom of the vertical casing 1 is provided with a vortex type soot blowing assembly 15 , and the vortex type soot blowing assembly 15 is shown in FIG. The blowing pipe 19, the blowing pipe 19 is arranged on the outer wall of the vertical casing 1 along the same inclined direction on the horizontal plane, the blowing pipe 19 is externally connected to the compressed air source 12, and the compressed air is sprayed into the vertical casing 1 through the blowing pipe 19 to form The airflow vortex on the horizontal plane (as shown in Figure 1, the direction of the inclination of the blowing pipe 19, the counterclockwise airflow vortex is formed inside the vertical housing 1), and the dust-prone area at the bottom of the vertical housing 1 is sprayed and cleaned. , the angle between the blowing pipe 19 and the outer wall surface of the vertical casing 1 is 15°. The outlet flue 3 is provided with a particle detection device 18 .

A first soot blowing device 7 is arranged above the first catalyst layer 4, a second soot blowing device 8 is arranged above the second catalyst layer 5, and a third soot blowing device 9 is arranged above the third catalyst layer 6. The catalyst layer is sprayed to remove dust. The compressed air inlets of the soot blowing devices of each layer are combined into one channel and then connected to the compressed air source 12 through the compressed air main pipe 10 , and the compressed air source 12 respectively provides compressed air to different soot blowing devices through the compressed air main pipe 10 . The compressed air main pipe 10 is also provided with a heating device 11, and the compressed air provided by the compressed air source 12 is heated by the heating device 11 and distributed to different soot blowing devices. The soot blowing device and the blowing pipe 19 share the same compressed air source 12, and the connection between the three is as follows: the compressed air main pipe 10 is provided with a peripheral compressed air branch pipe 13, and the outlet end of the compressed air branch pipe 13 is connected to the blowing pipe 19, and the compressed air branch pipe 13 is connected to the blowing pipe 19. The compressed air provided by the air source 12 is heated by the heating device 11 and then passed into the spray pipe 19 to spray and clean the dust accumulation area at the bottom of the vertical casing 1 . The compressed air branch pipe 13 is provided with a regulating valve 14 .

Example 2

The difference between this embodiment and Embodiment 1 in terms of structural parameters is:

(1) The catalyst used in the three-layer catalyst layer includes a carrier, active components and auxiliary components supported on the carrier, the carrier is molecular sieve, the active component is V ₂ O ₅ , and the auxiliary component is WO ₃ .

(2) Four groups of arc-straight deflectors with segmented structure are arranged inside the turning flue where the inlet flue 2 is connected to the vertical shell 1, and the four groups of arc-straight deflectors are divided into two groups according to different structures. baffles 17 and 2 sets of outer baffles 16;

(3) The angle between the inner straight deflector and the vertical direction is 7°;

(4) A four-layer rectifying grid is arranged on the top of the vertical housing 1, and the distance between two adjacent rectifying grids is controlled at 60mm;

(5) The angle between the blowing pipe 19 and the outer wall surface of the vertical casing 1 is 20°;

The remaining structural features are exactly the same as those in Embodiment 1, and will not be repeated here.

Example 3

The difference between this embodiment and Embodiment 1 in terms of structural parameters is:

(1) The catalyst used in the three-layer catalyst layer includes a carrier, active components and auxiliary components supported on the carrier, the carrier is mesoporous alumina, the active component is V ₂ O ₅ , and the auxiliary component is WO ₃ ;

(2) Five groups of arc-straight deflectors with segmented structure are arranged inside the turning flue where the inlet flue 2 is connected to the vertical shell 1, and the five groups of arc-straight deflectors are divided into 3 groups according to different structures. baffles 17 and 2 sets of outer baffles 16;

(3) The angle between the inner straight deflector and the vertical direction is 10°;

(4) Two layers of rectifying grids are arranged on the top of the vertical housing 1, and the distance between two adjacent rectifying grids is controlled at 70mm;

(5) The angle between the blowing pipe 19 and the outer wall surface of the vertical casing 1 is 30°.

The remaining structural features are exactly the same as those in Embodiment 1, and will not be repeated here.

Example 4

The difference between this embodiment and Embodiment 1 in terms of structural parameters is:

(1) The catalyst used in the three-layer catalyst layer includes a carrier, active components and auxiliary components supported on the carrier, the carrier is montmorillonite, the active component is V ₂ O ₅ , and the auxiliary component is WO ₃ ;

(2) The curved flue where the inlet flue 2 is connected to the vertical casing 1 is provided with six groups of arc-straight deflectors with a segmented structure, and the six groups of arc-straight deflectors are divided into three groups according to different structures. baffles 17 and 3 sets of outer baffles 16;

(3) The angle between the inner straight deflector and the vertical direction is 12°;

(4) Two layers of rectifying grids are arranged on the top of the vertical housing 1, the rectifying grids are arranged at equal intervals, and the distance between two adjacent rectifying grids is controlled at 80mm;

(5) The angle between the blowing pipe 19 and the outer wall surface of the vertical casing 1 is 40°.

The remaining structural features are exactly the same as those in Embodiment 1, and will not be repeated here.

Example 5

The difference between this embodiment and Embodiment 1 is:

(1) The curved flue where the inlet flue 2 is connected to the vertical shell 1 is provided with three groups of arc-straight deflectors with a segmented structure. Flow plate 17 and 2 sets of outer guide plates 16;

(2) The angle between the inner straight deflector and the vertical direction is 15°;

(3) Two layers of rectifying grids are arranged on the top of the vertical housing 1, and the distance between the two layers of rectifying grids is controlled at 100mm;

(4) The angle between the blowing pipe 19 and the outer wall surface of the vertical casing 1 is 45°.

The remaining structural features are exactly the same as those in Embodiment 1, and will not be repeated here.

Application Example

The SCR reaction device provided in Example 1 is used to carry out SCR denitration treatment on the kiln tail gas of the cement kiln, and the treatment process specifically includes the following steps:

(1) In the early stage of operation of the SCR reaction device, the flue gas discharged from the kiln tail flue of the cement kiln flows into the inlet flue 2 of the SCR denitration device, passes through the guide plate to improve the uniformity of the distribution of the flue gas, and then passes through the rectification grid , the speed uniformity of the flue gas is improved, the nitrogen oxides and the reducing agent (ammonia) in the flue gas react on the catalyst layer to generate nitrogen and water, the flue gas is purified, and the flue gas passes through the first catalyst layer 4, The second catalyst layer 5 and the third catalyst layer 6 are then discharged from the outlet flue 3. The particulate matter detection device 18 detects the concentration of particulate matter in the exhaust smoke from the outlet flue 3, and the detected particulate matter concentration at the outlet is less than 20 mg/Nm ³ , indicating that this When there is less dust accumulation on the inner wall and bottom of the SCR reaction device, the regulating valve 14 is closed, the soot blowing assembly 15 stops working, the use of compressed air and heating device 11 is reduced, and the operating cost is reduced. After running for a period of time, the particulate matter in the flue gas blocks the catalyst layer, the compressed air provided by the compressed air source 12 is preheated by the heating device 11 and then passed into the soot blowing device, and blows the opposite catalyst layer below to remove the dust to reduce the catalyst layering. The soot is blocked, and the temperature difference between the compressed air and the flue gas is reduced by preheating; the soot blowing frequency of the soot blowing device to the catalyst layer is 1 to 3 times a day.

(2) In the later operation process, the particulate matter detection device 18 detects that the outlet particulate matter concentration in the exhaust smoke from the outlet flue 3 is greater than 20 mg/Nm ³ , indicating that the inner wall and bottom of the SCR reaction device at this time are seriously fouled, and it is turned on at this time. Adjustment valve 14, the opening degree of the adjustment valve 14 is adjusted to half the size, the compressed air provided by the compressed air source 12 is preheated by the heating device 11 and sent to the scroll soot blowing assembly 15, and the preheated compressed air is passed through the blowing pipe 19. The 30° inclined jet is injected into the ash accumulation area at the bottom of the vertical casing 1, and the compressed air forms a vortex air flow on the horizontal plane at the bottom of the vertical casing 1, so as to realize the cleaning of the ash accumulation at the bottom.

The applicant declares that the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should Changes or substitutions that can be easily conceived within the technical scope all fall within the protection scope and disclosure scope of the present invention.

Claims (10)

1. The vortex type soot blowing assembly is characterized by comprising at least three blowing pipes arranged along the circumferential direction of a shell, wherein the blowing pipes are obliquely arranged on the outer wall surface of the shell along the same direction of the periphery of the shell, the blowing pipes are externally connected with a compressed air source, and compressed air is sprayed into the shell through the blowing pipes to form airflow vortexes to blow and remove soot in an area easy to deposit soot in the shell.

2. The vortex type soot blowing assembly as claimed in claim 1, wherein the blowing tube is horizontally arranged along the circumference of the housing, the blowing tube is obliquely arranged on the outer wall surface of the housing along the same oblique direction on the horizontal plane, and the compressed air is injected into the interior of the housing through the blowing tube to form an airflow vortex on the horizontal plane;

preferably, the cross section of the shell is polygonal, and at least one blowing pipe is arranged on the outer wall surface of each side of the shell;

preferably, in the horizontal plane, the included angle between the blowing pipe and the outer wall surface of the shell is 15-45 degrees, and compressed air is sprayed into the shell at an oblique angle of 15-45 degrees;

preferably, the section of the shell is circular, and at least three blowing pipes are arranged on the outer wall surface of the shell at equal intervals;

preferably, in the horizontal plane, the included angle between the tangent line of the connecting point of the injection tube and the shell and the injection tube is 15-45 degrees, and the compressed air is injected into the shell at an oblique angle of 15-45 degrees.

3. The SCR reaction device is characterized by comprising a vertical shell and at least one catalyst layer which is transversely arranged in the vertical shell;

the bottom of the vertical shell is provided with a vortex type soot blowing assembly as claimed in any one of claims 1 to 4.

4. The SCR reaction device of claim 3, wherein a horizontal reducing inlet flue is arranged at an inlet at the top of the vertical shell, a horizontal reducing outlet flue is arranged at an outlet at the bottom of the vertical shell, and flue gas enters the vertical shell from the inlet flue along the horizontal direction, sequentially passes through the catalyst layer from top to bottom, and then is discharged from the outlet flue along the horizontal direction;

preferably, at least two groups of guide plates are arranged in the turning flue of which the inlet flue is in butt joint with the vertical shell, and the guide plates are used for changing the flow direction of flue gas entering the inlet flue;

preferably, the guide plate is an arc straight guide plate with a segmented structure;

preferably, at least one layer of rectifying grating is arranged at the top of the vertical shell;

preferably, the rectifying grids are arranged at equal intervals;

preferably, the distance between two adjacent rectification grids is controlled to be 40-100 mm;

preferably, the soot blowing assembly is arranged on the outer wall surface of the vertical shell above the outlet flue;

preferably, the outlet flue is provided with a particulate matter detection device, and the particulate matter detection device is used for detecting the concentration of particulate matter in the exhaust smoke of the outlet flue.

5. The SCR reaction device of claim 3 or 4, wherein the guide plate is divided into an inner guide plate and an outer guide plate, the inner guide plate is arranged at the inner side of the turning flue with the inlet flue in butt joint with the vertical shell, the outer guide plate is arranged at the outer side of the turning flue with the inlet flue in butt joint with the vertical shell, and the inner guide plate and the outer guide plate are radially distributed along the flow direction of flue gas;

preferably, the inner side guide plate comprises an inner side arc guide plate and an inner side straight guide plate which are butted with each other along the flow direction of the flue gas, and the inner side arc guide plate extends towards the inner side of the turning flue to form the inner side straight guide plate;

preferably, the included angle between the inner side straight guide plate and the vertical direction is 5-15 degrees;

preferably, the outside guide plate along the flue gas flow direction including the outside arc guide plate and the outside straight guide plate of butt joint, outside arc guide plate along vertical direction extension formation outside straight guide plate.

6. The SCR reaction device of any one of claims 3 to 5, wherein a soot blower is arranged above each catalyst layer and used for blowing soot to the catalyst layers;

preferably, after the compressed air inlets of the soot blowers are combined into one path, a compressed air source is connected through a compressed air main pipe, and the compressed air source provides compressed air for different soot blowers through the compressed air main pipe respectively;

preferably, a heating device is arranged on the compressed air main pipe, and compressed air provided by a compressed air source is heated by the heating device and then distributed to different soot blowers;

preferably, the soot blower and the blowing pipe respectively use different compressed air sources or share the same compressed air source, and further preferably, the soot blower and the blowing pipe share the same compressed air source;

preferably, a compressed air branch pipe is arranged outside the compressed air main pipe, the outlet end of the compressed air branch pipe is connected to the blowing pipe, and compressed air provided by a compressed air source is heated by a heating device and then is introduced into the blowing pipe to blow and clean ash on an area easy to deposit ash at the bottom of the vertical shell;

preferably, the compressed air branch pipe is provided with a regulating valve.

7. The SCR reaction device according to any one of claims 3 to 6, wherein the catalyst used in the catalyst layer comprises a carrier and an active component and an auxiliary component supported on the carrier;

preferably, the support comprises TiO₂One or the combination of at least two of molecular sieve, mesoporous alumina or montmorillonite;

preferably, the active ingredient comprises V₂O₅；

Preferably, the adjunct ingredient comprises WO₃。

8. The SCR reaction device according to any one of claims 3 to 7, wherein the vertical casing has a first catalyst layer, a second catalyst layer and a third catalyst layer provided therein at intervals in a flow direction of the flue gas.

9. A method for denitration of flue gas by using the SCR reactor according to any one of claims 3 to 8, the method comprising:

the flue gas enters an SCR reaction device, sequentially passes through a catalyst layer from bottom to top, and is subjected to selective catalytic oxidation reaction with a reducing agent under the action of a catalyst to remove NO in the flue gas_xAnd the soot blowing component is used for blowing and cleaning soot in an area which is easy to accumulate soot in the vertical shell at regular intervals.

10. The method according to claim 9, characterized in that it comprises in particular the steps of:

the flue gas enters an SCR reaction device, sequentially passes through a catalyst layer from bottom to top, and is subjected to selective catalytic oxidation reaction with a reducing agent under the action of a catalyst to remove NO in the flue gas_x；

(II) preheating compressed air provided by a compressed air source through a heating device, distributing the preheated compressed air into different soot blowing devices, and periodically blowing and cleaning soot on a catalyst layer;

(III) compressed air provided by a compressed air source is preheated by a heating device and then is introduced into an injection pipe, and the compressed air is injected into the vertical shell to form airflow vortex on the horizontal plane, so that injection and ash removal of an area easy to deposit ash at the bottom of the vertical shell are realized;

preferably, in the step (II), the soot blowing frequency of the soot blowing device to the catalyst layer is 1-3 times a day;

preferably, when the concentration of the particulate matters in the flue gas discharged from the outlet flue is more than 20mg/Nm³And (5) opening the regulating valve to perform the step (III).

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