Cement kiln scr denitration reaction system

Abstract

The present application relates to a kind of cement kiln SCR denitration reaction systems, including reactor main body, main catalyst unit, reactor main body is connected with import flue and export flue, main catalyst unit is arranged in reactor main body, system further includes one or more of first dust arresting unit, second dust arresting unit, first dust arresting unit is arranged in import flue, first dust arresting unit is provided with the flue gas passage that allows flue gas to pass through, the opening size of flue gas passage can be adjusted;Second dust arresting unit is arranged in reactor main body and is located above main catalyst unit, and second dust arresting unit is provided with the flue gas hole that allows flue gas to pass through.The present application can be efficiently intercepted and transport fly ash in flue gas by dust arresting unit, while multiple measures ensure that fly ash is removed before passing through catalyst, extend the service life of catalyst;Dust arresting unit structure is simple, easy to install, and cost saving.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of SCR denitration, and particularly relates to a cement kiln SCR denitration reaction system. BACKGROUND

[0002] The NOx contained in the exhaust gas discharged from a cement kiln pollutes the environment greatly, and the NOx combined with water in the air will eventually be converted into nitric acid and nitrate, so certain measures must be taken to remove as much NOx as possible in the exhaust gas discharged from the cement kiln to reduce the pollution to the environment.

[0003] The technical measures for controlling NOx emission can be divided into two categories: one is so-called source control, which controls the generation reaction of NOx in the combustion process through various technical means; the other is so-called tail control, which reduces the emission of NOx by reducing the generated NOx to N2 through certain means.

[0004] Currently, in order to achieve ultra-low emission of NOx, the selective catalytic reduction (SCR) denitration technology is often used in the kiln treatment in the cement kiln industry. The catalyst, as the core material of the SCR denitration technology, becomes the main factor restricting the denitration reaction. The existing process often arranges high-ash and high-dust. Since the space of the cement production line is often limited, the inlet transition flue forms are various, and it is impossible to set a fixed ash collecting device, plus the extremely high fly ash concentration of the cement kiln, in order to prevent the accumulation of ash on the catalyst and improve the denitration efficiency, a soot blowing device is usually arranged above each layer of catalyst, but the existing soot blowing device has a complex structure, and the soot blowing efficiency and effect are poor, frequent soot blowing treatment of the kiln is required, and the effect is poor. SUMMARY

[0005] The purpose of the present application is to provide a cement kiln SCR denitration reaction system.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0007] A cement kiln SCR denitration reaction system, comprising a reactor main body, a main catalyst unit, the reactor main body is connected with an inlet flue and an outlet flue, the main catalyst unit is arranged in the reactor main body,

[0008] The system further comprises one or more of a first ash blocking unit and a second ash blocking unit, the first ash blocking unit is arranged in the inlet flue, the first ash blocking unit is provided with a flue gas passage allowing flue gas to pass through, and the opening size of the flue gas passage is adjustable; the second ash blocking unit is arranged in the reactor main body above the main catalyst unit, and the second ash blocking unit is provided with a flue gas hole allowing flue gas to pass through.

[0009] Preferably, the first dust blocking unit comprises a dust blocking plate group, a dust blocking driving element, the dust blocking plate group is provided with multiple groups, multiple groups of the dust blocking plate group are located at the same section of the inlet flue and are distributed vertically, the smoke passage is formed between two adjacent groups of the dust blocking plate group; the dust blocking plate group comprises a first plate body and a second plate body, the opening size of the smoke passage can be adjusted by relative rotation between the first plate body and the second plate body, the relative rotation of the first plate body and the second plate body is driven by the dust blocking driving element, the fly ash before entering the reactor body is intercepted and pre-collected by arranging the first dust blocking unit in the inlet flue, the catalyst pressure is relieved, and the automatic adjustment of the dust blocking of the smoke passage is realized by the self-rotation adjustment of the first plate body and the second plate body.

[0010] Further preferably, the included angle between the first plate body and the second plate body is 18°-60°.

[0011] Preferably, the first dust blocking unit further comprises a concentration monitor for monitoring the ash concentration in the reactor body and a differential pressure monitor for monitoring the flue gas resistance in the reactor body, the dust blocking driving element adjusts the angle between the first plate body and the second plate body according to the monitoring data of the concentration monitor and the differential pressure monitor, by monitoring the threshold values of the ash load concentration and the flue resistance, the opening size of the smoke passage can be adjusted according to the ash load and the flue gas pressure, and finally the ash blocking effect is achieved.

[0012] Preferably, the second dust blocking unit comprises a dust blocking plate and a dust guiding passage, the smoke hole is formed in the dust blocking plate, the dust accumulation groove is formed by concave under the dust blocking plate, the upper end of the dust guiding passage is communicated with the two ends of the dust accumulation groove respectively, and the lower end of the dust guiding passage extends to the outlet flue.

[0013] Further preferably, a control valve is arranged at the inlet of the dust guiding passage.

[0014] Further preferably, the dust guiding passage is provided with multiple.

[0015] Further preferably, the cross section of the dust guiding passage is trapezoidal.

[0016] Further preferably, the second dust blocking unit further comprises a dust pushing assembly, the dust pushing assembly is used for pushing the dust in the dust accumulation groove into the dust guiding passage, the dust pushing assembly comprises a dust pushing plate and a dust pushing driving element, the dust pushing plate is arranged in the dust accumulation groove, and the dust pushing driving element is connected with the dust pushing plate to drive the reciprocating movement of the dust pushing plate in the dust accumulation groove.

[0017] Further preferably, the ash pushing plate is provided with holes, and during the ash pushing process, the accumulated ash can pass through the holes, thereby reducing the resistance of the ash pushing plate during the pushing process.

[0018] Further preferably, the ash pushing plate is vertically arranged in the ash accumulation groove.

[0019] Further preferably, the shape of the ash pushing plate is consistent with the cross-sectional shape of the ash accumulation groove.

[0020] Further preferably, the second ash blocking unit further comprises ash blowing members arranged on both sides of the ash blocking plate for blowing the accumulated ash on the ash blocking plate into the ash accumulation groove.

[0021] Preferably, the system comprises a first ash hopper, an ash conveying pipe, the first ash hopper is arranged in the inlet flue at the front of the first ash blocking unit, one end of the ash conveying pipe is in communication with the first ash hopper, and the other end of the ash conveying pipe is in communication with the outlet flue.

[0022] Preferably, the top of the reactor body extends downwardly from one side of the inlet flue to the opposite side, the system further comprises a second ash hopper and an ash conveying pipe, the second ash hopper is arranged in the reactor body opposite to the other side of the inlet flue, one end of the ash conveying pipe is in communication with the second ash hopper, and the other end of the ash conveying pipe is in communication with the outlet flue. Due to the inertia of the flue gas, a large amount of fly ash is carried through the inclined top of the reactor body, and the fly ash carried by the flue gas near the upper part of the flue is collected into the second ash hopper. The collected fly ash can be collected into the outlet flue after falling into the second ash hopper.

[0023] Preferably, the outlet flue is provided with a Venturi pipe section, the Venturi pipe section is tapered to be gradually expanded, and the previous ash is sucked into the outlet flue through the Venturi effect and discharged into the downstream dust removal equipment.

[0024] Preferably, the system further comprises an auxiliary catalyst unit, the auxiliary catalyst unit is arranged in the outlet flue, and the auxiliary catalyst unit absorbs a small amount of flue gas that has not been reacted by the main catalyst unit.

[0025] Thanks to the above technical scheme, the present application has the following advantages compared with the prior art:

[0026] The ash blocking unit can efficiently intercept and transport the fly ash in the flue gas, and a plurality of measures are taken to ensure that the fly ash is removed before passing through the catalyst, thereby prolonging the service life of the catalyst. The ash blocking unit has a simple structure, is easy to install, and saves costs. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a structural schematic diagram of the reactor body of the present embodiment; Figure 1 Figure 2 is a structural schematic diagram of the first ash blocking unit of the present embodiment;

[0028] Figure 3 is a structural schematic diagram of the ash blocking unit group of the present embodiment; Figure 2 Figure 4 is a structural schematic diagram of the ash blocking unit of the present embodiment;

[0029] Figure 5 is a structural schematic diagram of the ash pushing unit of the present embodiment; Figure 3 Figure 6 is a structural schematic diagram of the ash pushing unit of the present embodiment;

[0030] Figure 7 is a structural schematic diagram of the ash pushing unit of the present embodiment. Figure 4 In the above figures:

[0031] 1, reactor body; 10, inlet flue; 11, outlet flue; 110, Venturi pipe section; 2, main catalyst unit; 3, first ash blocking unit; 30, flue gas passage; 31, first plate body; 32, second plate body; 40, ash blocking unit; 400, flue gas hole; 401, ash accumulation groove; 41, ash guiding passage; 42, ash blowing element; 43, ash pushing unit; 430, hole; 44, rod element; 50, first ash hopper; 51, ash conveying pipe; 60, second ash hopper; 61, ash conveying pipe; 7, auxiliary catalyst unit.

[0032] DETAILED DESCRIPTION The technical solutions of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0033] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0034]

[0035] ​In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] like Figure 1 The image shows an SCR denitrification reaction system for a cement kiln, comprising a reactor body 1 and a main catalyst unit 2. The reactor body 1 is connected to an inlet flue 10 and an outlet flue 11, and the main catalyst unit 2 is disposed within the reactor body 1. The inlet flue 10 extends horizontally, and the outlet flue 11 extends downwards at an angle.

[0037] The system also includes a first ash-blocking unit 3 and a second ash-blocking unit. The first ash-blocking unit 3 and the second ash-blocking unit will be described in detail below.

[0038] The first ash-blocking unit 3 is installed inside the inlet flue 10. The first ash-blocking unit 3 has a flue gas passage 30 that allows flue gas to pass through, and the opening size of the flue gas passage 30 is adjustable. For example... Figure 2 As shown: In this embodiment, the first ash-blocking unit 3 includes an ash-blocking plate assembly, an ash-blocking drive component, a controller, etc. Multiple ash-blocking plate assemblies are provided, located at the same cross-section of the inlet flue 10 and distributed vertically, forming a flue gas passage 30 between adjacent ash-blocking plate assemblies. Specifically, the ash-blocking plate assembly includes a first plate 31 and a second plate 32, which are rotatable relative to each other. The ash-blocking drive component drives the relative rotation of the first plate 31 and the second plate 32. The first plate 31 and the second plate 32 are rectangular stainless steel sheets, which can be connected to rotating shafts respectively. The ash-blocking drive component drives the first plate 31 and the second plate 32 to achieve relative rotation through the driving shafts. The first plate 31 and the second plate 32 can be a single plate extending along both sides of the inlet flue 10, or they can be... Figure 2 The diagram shows multiple plates. When the horizontal angle between the first plate 31 and the second plate 32 is 0°, the opening of the flue gas passage 30 between two adjacent sets of ash-blocking plates is at its maximum, allowing all flue gas to flow through without obstruction. Preferably, the included angle between the first plate 31 and the second plate 32 is 18°-60°. By setting the first ash-blocking unit 3 in the inlet flue duct 10, fly ash before entering the reactor body 1 is intercepted and pre-collected, relieving catalyst pressure.

[0039] The first ash blocking unit 3 further comprises a concentration monitor for monitoring the concentration of ash in the reactor body and a differential pressure monitor for monitoring the resistance of flue gas in the reactor body, and the concentration monitor and the differential pressure monitor are connected to the controller. The concentration monitor and the differential pressure monitor can be respectively arranged on both sides of the first ash blocking unit 3, and by monitoring the two parameters of the ash load concentration and the flue resistance threshold value, the opening size of the flue gas passage can be adjusted according to the ash load and the flue gas pressure, so as to finally achieve the effect of blocking the ash.

[0040] The working process of the first ash blocking unit 3 is as follows: when the flue gas flows through the concentration monitor and the differential pressure monitor, if the total concentration of the ash monitored by the concentration monitor is higher than the design value, a feedback signal is fed back to the controller, the controller adjusts the included angle of the first plate body 31 and the second plate body 32, the ash blocking driving member drives the first plate body 31 and the second plate body 32 to rotate and adjust, and the size of the flue gas passage 30 is adjusted; if the differential pressure monitor monitors that the first ash blocking unit 3 causes the flue resistance to be too high, the differential pressure monitor alarms, a feedback signal is fed back to the controller, the controller adjusts the included angle of the first plate body 31 and the second plate body 32, the size of the flue gas passage 30 is adjusted, the pressure difference is reduced, and the accumulated fly ash is dropped. When the ash is too high and the pressure difference is lower than the alarm value, the system starts to work again.

[0041] The second ash blocking unit is arranged in the reactor body 1 above the main catalyst unit 2, and the second ash blocking unit is provided with flue gas holes 400 allowing the flue gas to pass through. Figure 3 As shown in the embodiment: the second ash blocking unit comprises an ash blocking plate 40, a guide ash passage 41 and an ash blowing member 42. The ash blocking plate 40 is provided with flue gas holes 400, the lower part of the ash blocking plate 40 is recessed to form an ash accumulation groove 401, the upper ends of the guide ash passages 41 are respectively connected to the two ends of the ash accumulation groove 401, the lower ends of the guide ash passages 41 extend to the outlet flue 11, and the ash blowing member 42 is arranged on both sides of the ash blocking plate 40 for blowing the accumulated ash on the ash blocking plate 40 into the ash accumulation groove 41, relying on the flue gas and the ash blowing member 42 to carry away the fly ash accumulated on the ash blocking plate 40, and realizing the self-cleaning effect. The ash blocking plate 40 can adopt a guide ash grid, the guide ash passage 41 is provided with a plurality of guide ash passages, two guide ash passages are shown in the figure, and the cross section of the guide ash passage 41 is trapezoidal; a control valve such as a one-way bearing valve is arranged at the inlet of the guide ash passage 41; and the ash blowing member 42 can adopt an air cannon.

[0042] The second ash blocking unit further comprises an ash pushing assembly for pushing the accumulated ash in the ash accumulation groove 401 into the guide ash passage 41. Figure 4As shown, in the present embodiment: the ash pushing assembly includes an ash pushing plate 43, an ash pushing drive (such as a motor, etc.), the ash pushing plate 43 is vertically arranged in the ash accumulation groove 401, and the ash pushing drive is connected with the ash pushing plate 43 through a rod 44 to drive the ash pushing plate 43 to reciprocate in the ash accumulation groove 401. The ash pushing plate 43 is provided with a hole 430, and during the ash pushing process, the accumulated ash can pass through the hole 430 to reduce the resistance of the ash pushing plate 43 during the pushing process. The shape of the ash pushing plate 43 is consistent with the cross-sectional shape of the ash accumulation groove 401.

[0043] In addition, a weight sensor can be arranged at the bottom of the ash accumulation groove 401. When the fly ash accumulated in the ash accumulation groove 401 reaches a certain degree, the ash pushing assembly starts to work, and the ash pushing plate 43 repeatedly pushes in the ash accumulation groove 401, so that the ash is pushed into the ash guiding channel 41. The control valve of the ash guiding channel 41 is opened, and the ash is discharged to the outlet flue 11; when the ash pushing plate 43 is not working, the control valve is closed to prevent the untreated flue gas from flowing out of the channel.

[0044] The system further includes a first ash hopper 50 and an ash conveying pipe 51. The first ash hopper 50 is arranged in the inlet flue 10 at the front of the first ash blocking unit 3, and a load-bearing one-way valve is arranged at the bottom of the first ash hopper 50. One end of the ash conveying pipe 51 is in communication with the first ash hopper 50, and the other end of the ash conveying pipe 51 is in communication with the outlet flue 11. The ash intercepted by the first ash blocking unit 3 falls into the first ash hopper 50 for collection. When the ash reaches a certain weight, the load-bearing one-way valve is opened to discharge the ash to the outlet flue 11.

[0045] The top of the reactor body 1 extends downward from one side of the inlet flue 10 to the opposite side. The system further includes a second ash hopper 60 and an ash conveying pipe 61. The second ash hopper 60 is arranged in the reactor body 1 opposite the other side of the inlet flue 11. One end of the ash conveying pipe 61 is in communication with the second ash hopper 60, and the other end of the ash conveying pipe 61 is in communication with the outlet flue 11. Due to the inertia of the flue gas, a large amount of fly ash carried by the flue gas passes through the inclined top of the reactor body 1, and the fly ash carried by the flue gas near the upper part of the flue is collected into the second ash hopper 60. The collected fly ash falls into the second ash hopper 60 and can be collected into the outlet flue 11 through the ash conveying pipe.

[0046] The outlet flue 11 is provided with a Venturi pipe section 110. The Venturi pipe section 110 is tapered to be gradually expanded. The ash guiding channel 41 and the ash conveying pipe 51 are both in communication with the outlet flue 11 upstream of the Venturi pipe section 110. Through the Venturi effect, the ash before is sucked into the outlet flue 11 and discharged into the downstream dust removal equipment to adsorb the fly ash without the aid of external power.

[0047] The system further includes an auxiliary catalyst unit 7 arranged at the outlet position of the outlet flue 11. The auxiliary catalyst unit absorbs a small part of the flue gas that has not been reacted due to the temporary opening of the control valve of the ash guiding channel 41.

[0048] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. A cement kiln SCR denitrification reaction system, comprising a reactor body and a main catalyst unit, wherein the reactor body is connected to an inlet flue and an outlet flue, and the main catalyst unit is disposed within the reactor body, characterized in that: The system further includes a first ash-blocking unit and a second ash-blocking unit. The first ash-blocking unit is installed inside the inlet flue and has a flue gas passage that allows flue gas to pass through. The opening size of the flue gas passage is adjustable. The first ash-blocking unit includes an ash-blocking plate assembly, an ash-blocking drive component, a concentration monitor for monitoring the ash concentration inside the reactor body, a differential pressure monitor for monitoring the flue gas resistance inside the reactor body, and a controller. Multiple ash-blocking plate assemblies are provided, and the multiple ash-blocking plate assemblies are located at the same cross section of the inlet flue and distributed vertically. The flue gas passage is formed between two adjacent ash-blocking plate assemblies. The ash-blocking plate assembly includes a first plate and a second plate. The first and second plates can rotate relative to each other to adjust the opening size of the flue gas passage. The ash-blocking drive unit drives the relative rotation of the first and second plates. The concentration monitor and differential pressure monitor are connected to the controller. Flue gas flows through the concentration monitor and differential pressure monitor. When the concentration monitor detects that the total ash concentration is higher than the design value, it sends a feedback signal to the controller. The controller adjusts the angle between the first and second plates, and the ash-blocking drive unit drives the first and second plates to rotate and adjust, thereby adjusting the size of the flue gas passage. When the differential pressure monitor detects that the first ash-blocking unit causes excessive flue resistance, the differential pressure monitor alarms and sends a feedback signal to the controller. The controller adjusts the angle between the first and second plates to reduce the pressure difference and cause the accumulated fly ash to fall off. The second ash-blocking unit is located above the main catalyst unit within the reactor body. The second ash-blocking unit has flue gas holes that allow flue gas to pass through. It includes an ash-blocking plate, an ash-guiding channel, and an ash-pushing assembly. The ash-blocking plate has the flue gas holes and is recessed to form an ash-collecting groove. The upper end of the ash-guiding channel connects to both ends of the ash-collecting groove, and the lower end extends to the outlet flue. The ash-pushing assembly pushes the accumulated ash in the ash-collecting groove into the ash-guiding channel. The ash-pushing assembly includes a ash-pushing plate and a ash-pushing drive component. The ash-pushing plate has holes and is positioned within the ash-collecting groove. The shape of the ash-pushing plate matches the cross-sectional shape of the ash-collecting groove. The ash-pushing drive component is connected to the ash-pushing plate and drives it to reciprocate within the ash-collecting groove.

2. The cement kiln SCR denitrification reaction system according to claim 1, characterized in that: The second ash-blocking unit further includes ash-blowing components, which are disposed on both sides of the ash-blocking plate to blow the accumulated ash on the ash-blocking plate into the ash-collecting trough.

3. The cement kiln SCR denitrification reaction system according to claim 1, characterized in that: The system includes a first ash hopper and an ash conveying pipe. The first ash hopper is located in front of the first ash blocking unit inside the inlet flue. One end of the ash conveying pipe is connected to the first ash hopper, and the other end of the ash conveying pipe is connected to the outlet flue.

4. The cement kiln SCR denitrification reaction system according to claim 1, characterized in that: The top of the reactor body extends downwards at an angle from one side of the inlet flue to the opposite side. The system also includes a second ash hopper and an ash conveying pipe. The second ash hopper is located inside the reactor body on the opposite side of the inlet flue. One end of the ash conveying pipe is connected to the second ash hopper, and the other end of the ash conveying pipe is connected to the outlet flue.

5. The cement kiln SCR denitrification reaction system according to claim 1, characterized in that: The outlet flue is equipped with a venturi riser section.

6. The cement kiln SCR denitrification reaction system according to claim 1, characterized in that: The system also includes an auxiliary catalyst unit, which is disposed within the outlet flue.

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