A flue gas denitration device for a cement kiln

Abstract

The present invention relates to the technical field of flue gas treatment, and specifically relates to a flue gas denitration device for a cement kiln, which includes a furnace chamber. A first flue gas passage is provided at the top of the furnace chamber. A second flue gas passage is provided on one side of the first flue gas passage. A second air outlet passage is provided at the bottom end of the second flue gas passage. The device further includes a first air outlet passage provided at the bottom of the first flue gas passage; a baffle rotatably provided in the first air outlet passage. In the present invention, a gas detector is provided in the first flue gas passage, and a rotatable baffle is provided between the first air outlet passage and the second flue gas passage. After denitrifying the high-temperature flue gas through SNCR, the denitrified flue gas is detected. After passing the detection, the flue gas is discharged from the first air outlet passage. However, if the standard is exceeded, the first air outlet passage can be closed by the baffle, and the second flue gas passage can be connected to denitrify the flue gas through SCR, and an appropriate amount of reducing agent can be adjusted according to the specific concentration.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas treatment, and in particular to a flue gas denitrification device for a cement kiln. Background Art

[0002] Furnace flue gas typically contains large amounts of nitrogen oxides (NOx), such as NO. Directly emitting these oxides into the atmosphere pollutes the air, forming photochemical smog and acid rain, which are harmful to human health. Therefore, flue gas must undergo denitrification (denitrification) before discharge. Currently, there are two main flue gas denitrification technologies: selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR). Selective catalytic reduction uses a reducing agent, such as liquid ammonia, aqueous ammonia, or urea, at a specific temperature and in the presence of a catalyst to selectively react with nitrogen oxides in the flue gas to produce non-toxic and non-polluting nitrogen and water. The SCR method operates at a relatively low reaction temperature (300-420°C) and achieves a denitrification efficiency exceeding 85%. SCR technology offers high denitrification efficiency and low ammonia slip.

[0003] In actual project operation, single denitrification technology is no longer able to meet increasingly stringent environmental protection targets. Therefore, SCR+SNCR combined denitrification technology has been widely used in boiler flue gas treatment. However, compared with single-stage SCR denitrification, the adjustment and control process of SCR+SNCR combined denitrification is much more complex, and more factors need to be considered during specific combined operation. In addition to ensuring that NOx emissions meet standards, the concentration range of ammonia slip must also be considered to prevent excessive dust accumulation in the air preheater and secondary pollution to the atmospheric environment caused by excessive injection of reducing agent. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned deficiencies and provide a flue gas denitrification device for a cement kiln.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A flue gas denitrification device for a cement kiln comprises a furnace, a first flue gas channel is provided at the top of the furnace, a second flue gas channel is provided on one side of the first flue gas channel, a second gas outlet channel is provided at the bottom end of the second flue gas channel, and further comprises:

[0007] a first gas outlet channel, arranged at the bottom of the first smoke channel;

[0008] a baffle, rotatably disposed in the first air outlet channel, for controlling the flow direction of the smoke;

[0009] a smoke filtering channel, provided between the first smoke channel and the second smoke channel, for filtering the smoke passing through the first smoke channel;

[0010] The gas detector is arranged in the first flue gas channel and is used to detect the content of nitrogen oxides in the flue gas.

[0011] Furthermore, a plurality of partition plates are provided in the first flue gas channel, a first reducing agent spray gun is provided between the partition plates, a guide plate is provided at one end of the partition plate away from the first reducing agent spray gun, a vortex channel is provided at one end of the guide plate away from the partition plate, a gas detector is provided on the side of the vortex channel away from the guide plate, and an economizer is provided at the bottom of the inner cavity of the first flue gas channel.

[0012] Furthermore, a filter screen is provided in the smoke filter channel, a slide is movably provided on the side wall of the filter screen, and a waste box is provided at one end of the slide screen away from the filter screen.

[0013] Furthermore, a brush plate is provided at one end of the slide close to the filter screen, and the brush plate is tightly attached to the filter screen. A driving component is provided at the bottom of the slide, and the driving component is used to drive the slide to slide along the surface of the filter screen.

[0014] Furthermore, the slide includes a first movable plate rotatably connected to the inner wall of the smoke filter channel, a second movable plate is rotatably provided at one end of the first movable plate, a sleeve plate is provided at one end of the second movable plate away from the first movable plate, a lifting plate is provided on the sleeve plate, the lifting plate is slidably connected to the filter screen, the brush plate is fixed on the lifting plate, and the movable end of the drive assembly is connected to the lifting plate.

[0015] Furthermore, the driving assembly includes two driving wheels rotatably arranged in the smoke filter channel, the driving wheels are rotatably connected to the smoke filter channel through a driving shaft, the two driving shafts are connected by a conveyor belt transmission, a protrusion is fixedly provided on the driving wheel, a push plate is fixedly provided at the bottom end of the lifting plate, a limit plate is fixedly provided at the end of the push plate away from the lifting plate, a movable groove is provided on the surface of the limit plate, and the protrusion slides in the movable groove.

[0016] Furthermore, a second reducing agent spray gun and a flue gas mixer are provided in the second flue gas channel, a plate catalyst is provided on one side of the flue gas mixer, and the plate catalyst is slidably connected to the second flue gas channel.

[0017] Furthermore, a lifting groove is provided on the inner wall of the second flue gas channel, a sliding rod is provided in the lifting groove, vibration plates are provided on both sides of the plate catalyst and are sleeved on the sliding rod, and a limit spring is provided on one side of the vibration plate and is sleeved on the sliding rod.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. In the present invention, a gas detector is provided in the first flue gas passage, and a flip - up baffle is provided between the first outlet passage and the second flue gas passage. After denitrifying the high - temperature flue gas by SNCR, the denitrified flue gas is detected. When the detection is qualified, the baffle can be rotated upward to block the second flue gas passage, allowing the flue gas to directly discharge from the first outlet passage. When the nitrogen oxides in the flue gas still exceed the standard, the first outlet passage can be closed by the baffle, and the second flue gas passage can be connected to denitrify the flue gas by SCR, and the appropriate amount of reducing agent can be adjusted according to the specific concentration.

[0020] 2. In the present invention, a flue gas filtration passage is also provided between the first flue gas passage and the second flue gas passage. Since there is a corner between the first flue gas passage and the second flue gas passage, ash accumulation is likely to occur. Therefore, when the flue gas enters the second flue gas passage, the accumulated ash can be cleaned to avoid excessive accumulation, and at the same time, the flue gas can be filtered, thereby improving the denitrification efficiency of SCR. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0022] Figure 1 is a schematic diagram of the main structure of the present invention;

[0023] Figure 2 is a schematic diagram of the internal structure of the first flue gas passage of the present invention;

[0024] Figure 3 is a connection diagram of the first flue gas passage and the first outlet passage of the present invention;

[0025] Figure 4 is a schematic diagram of the structure of the plate - type catalyst of the present invention;

[0026] Figure 5 is a schematic diagram of the structure of the flue gas filtration passage of the present invention;

[0027] Figure 6 is a connection diagram of two driving wheels of the present invention;

[0028] Figure 7 is a connection diagram of the driving wheel and the push plate of the present invention.

[0029] In the figure: 1, furnace; 2, first flue gas passage; 20, gas detector; 21, partition plate; 22, first reductant spray gun; 23, guide plate; 24, eddy current passage; 25, economizer; 3, second flue gas passage; 31, second reductant spray gun; 32, flue gas mixer; 33, plate catalyst; 331, vibrating plate; 332, sliding rod; 333, limiting spring; 4, first air outlet passage; 41, baffle; 5, flue gas filtration passage; 51, filter screen; 52, slideway; 521, first movable plate; 522, second movable plate; 523, sleeve plate; 524, lifting plate; 53, brush plate; 54, driving assembly; 541, driving wheel; 542, driving shaft; 543, convex block; 544, limiting plate; 545, push plate; 546, conveyor belt; 55, waste bin; 6, second air outlet passage. Detailed implementation mode

[0030] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the protection scope of the present invention.

[0031] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative position relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0032] Refer to Figures 1-7 As shown, a flue gas denitration device for a cement kiln includes a furnace 1. A first flue gas passage 2 is provided at the top of the furnace 1. The first flue gas passage 2 performs denitration operation through SNCR. A second flue gas passage 3 is provided on one side of the first flue gas passage 2. The second flue gas passage 3 performs secondary denitration operation through SCR. A special cooling device is also provided at the tail of the first flue gas passage 2. Mainly, when the flue gas just enters the first flue gas passage 2, the temperature is a high temperature of 850 - 1100 °C, while the temperature of the flue gas entering the second flue gas passage 3 needs to be controlled at 300 - 400 °C. A second air outlet passage 6 is provided at the bottom end of the second flue gas passage 3. It also includes:

[0033] A first air outlet passage 4 is provided at the bottom of the first flue gas passage 2. If the nitrogen oxides in the flue gas are in a qualified state after denitration through SNCR, they can be discharged through the first air outlet passage 4.

[0034] The gas detector 20 is installed in the first flue gas passage 2 and is used to detect the content of nitrogen oxides in the flue gas. It can determine subsequent operations based on the detection results.

[0035] The baffle 41 is rotatably arranged in the first air outlet passage 4. The baffle 41 is arranged between the first air outlet passage 4 and the second flue gas passage 3. If the flue gas is qualified, the baffle 41 can be flipped upwards to close the second flue gas passage 3, allowing the qualified flue gas to directly discharge from the first air outlet passage 4. If the flue gas is unqualified, the first air outlet passage 4 will be closed, allowing the flue gas to enter the second flue gas passage 3, which is used to control the flow direction of the flue gas.

[0036] The flue gas filtration passage 5 is arranged between the first flue gas passage 2 and the second flue gas passage 3. Since there is an inflection point from bottom to top between the two flue gas passages, ash accumulation is likely to occur at this place. Therefore, the flue gas can be filtered through the flue gas filtration passage 5, and the accumulated ash can also be cleaned.

[0037] In an embodiment, a plurality of partition plates 21 are arranged in the first flue gas passage 2. A first reducing agent spray gun 22 is arranged between the partition plates 21. Guide plates 23 are arranged at one end of the partition plates 21 away from the first reducing agent spray gun 22. There are two guide plates 23, and the two guide plates 23 are in an inwardly inclined state. A vortex passage 24 is arranged at one end of the guide plates 23 away from the partition plates 21. It can be set as a specific protrusion so that the flue gas can form a vortex, or a vortex tube can be arranged inside. After the flue gas enters it, it will automatically form a vortex. The gas detector 20 is arranged on one side of the vortex passage 24 away from the guide plates 23. A economizer 25 is arranged at the bottom of the inner cavity of the first flue gas passage 2. The economizer 25 can be used to absorb the high temperature of the flue gas and reduce the temperature of the flue gas to 300 - 400 °C.

[0038] The plurality of partition plates 21 can divide the flue gas into multiple channels, and a first reducing agent spray gun 22 is arranged in each channel, which is convenient for the mixing of the flue gas and the reducing agent. Then, after passing through the partition plates 21 and being guided by the guide plates 23, the flue gas in each channel converges in the vortex passage 24, and then the flue gas and the reducing agent form a vortex to accelerate the mixing.

[0039] In an embodiment, a filter screen 51 is arranged in the flue gas filtration passage 5. A slideway 52 is movably arranged on the side wall of the filter screen 51. A waste box 55 is arranged at one end of the slideway 52 away from the filter screen 51.

[0040] The slideway 52 is in an inclined state, and the end close to the filter screen 51 is at a higher position, which is convenient for the dust to enter the waste box 55 along the slideway 52.

[0041] In one embodiment, a brush plate 53 is provided at one end of the slide 52 close to the filter 51. The brush plate 53 is closely attached to the filter 51. A driving assembly 54 is provided at the bottom of the slide 52. The driving assembly 54 is used to drive the slide 52 to slide along the surface of the filter 51.

[0042] The driving assembly 54 can push the slide 52 to slide up and down along the filter 51 . When the slide 52 slides, the brush plate 53 can be driven to slide along the surface of the filter 51 to clean the surface of the filter 51 .

[0043] In one embodiment, the slide 52 includes a first movable plate 521 rotatably connected to the inner wall of the smoke filter channel 5. A second movable plate 522 is rotatably provided at one end of the first movable plate 521. A certain angle is also formed between the first movable plate 521 and the second movable plate 522. A sleeve plate 523 is sleeved on the end of the second movable plate 522 away from the first movable plate 521. A lifting plate 524 is provided on the sleeve plate 523. The lifting plate 524 is slidably connected to the filter screen 51. The brush plate 53 is fixed to the lifting plate 524. The movable end of the drive assembly 54 is connected to the lifting plate 524.

[0044] When the driving assembly 54 pushes the lifting plate 524, the lifting plate 524 slides upward along the surface of the filter screen 51. When the lifting plate 524 slides, it will pull the two movable plates to deflect. At the same time, the sleeve plate 523 will also slide along the second movable plate 522 to adapt to the changes of the entire slide 52.

[0045] In one embodiment, the driving assembly 54 includes two driving wheels 541 rotatably disposed in the smoke filter channel 5. The driving wheels 541 are rotatably connected to the smoke filter channel 5 via a driving shaft 542. The two driving shafts 542 are connected via a transmission belt 546, and a motor for driving is disposed on one of the driving shafts 542. In this way, the two driving wheels 541 can be driven to rotate together at the same time. A protrusion 543 is fixedly disposed on the driving wheel 541. The protrusion 543 is located on the side close to the driving wheel 541. A push plate 545 is fixedly disposed at the bottom end of the lifting plate 524. A limit plate 544 is fixedly disposed on the end of the push plate 545 away from the lifting plate 524. A movable groove is opened on the surface of the limit plate 544, and the protrusion 543 slides in the movable groove.

[0046] When the driving wheel 541 rotates, the protrusion 543 will be driven to rotate upward, and the protrusion 543 will push the limit plate 544, so that the push plate 545 will push the lifting plate 524 to slide upward; when the protrusion 543 rotates downward, the protrusion 543 will pull the limit plate 544, so that the push plate 545 will pull the lifting plate 524 to slide downward.

[0047] In one embodiment, a second reducing agent spray gun 31 and a flue gas mixer 32 are arranged in the second flue gas passage 3. A plate catalyst 33 is arranged on one side of the flue gas mixer 32, and the plate catalyst 33 is slidably connected to the second flue gas passage 3.

[0048] In one embodiment, a lifting groove is formed in the inner wall of the second flue gas passage 3. A sliding rod 332 is arranged in the lifting groove. Vibration plates 331 sleeved on the sliding rod 332 are arranged on both sides of the plate catalyst 33. A limiting spring 333 sleeved on the sliding rod 332 is arranged on one side of the vibration plate 331.

[0049] Under the blowing of the flue gas, the plate catalyst 33 can be driven to vibrate, preventing the interior of the plate catalyst 33 from being blocked.

[0050] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention.

Claims

1. A flue gas denitration device for a cement kiln, comprising a furnace chamber (1), a first flue gas passage (2) is arranged at the top of the furnace chamber (1), a second flue gas passage (3) is arranged on one side of the first flue gas passage (2), and a second air outlet passage (6) is arranged at the bottom end of the second flue gas passage (3), characterized in that, It further includes: A first gas outlet channel (4), arranged at the bottom of the first flue gas channel (2); A baffle plate (41), rotatably arranged in the first gas outlet channel (4) for controlling the flow direction of the flue gas; A flue gas filtration channel (5), arranged between the first flue gas channel (2) and the second flue gas channel (3) for filtering the flue gas passing through the first flue gas channel (2); A gas detector (20), arranged in the first flue gas channel (2) for detecting the content of nitrogen oxides in the flue gas; A plurality of partition plates (21) are arranged in the first flue gas channel (2). A first reductant spray gun (22) is arranged between the partition plates (21). Guide plates (23) are arranged at one end of the partition plates (21) away from the first reductant spray gun (22). There are two guide plates (23), and the two guide plates (23) are in an inwardly inclined state. An eddy current channel (24) is arranged at one end of the guide plates (23) away from the partition plates (21). The gas detector (20) is arranged on the side of the eddy current channel (24) away from the guide plates (23). A economizer (25) is arranged at the bottom of the inner cavity of the first flue gas channel (2); A filter screen (51) is arranged in the flue gas filtration channel (5). A slideway (52) is movably arranged on the side wall of the filter screen (51). A waste box (55) is arranged at one end of the slideway (52) away from the filter screen (51); A brush plate (53) is arranged at one end of the slideway (52) close to the filter screen (51). The brush plate (53) is closely attached to the filter screen (51). A driving assembly (54) is arranged at the bottom of the slideway (52) for driving the slideway (52) to slide along the surface of the filter screen (51); A second reductant spray gun (31) and a flue gas mixer (32) are arranged in the second flue gas channel (3). A plate catalyst (33) is arranged on one side of the flue gas mixer (32), and the plate catalyst (33) is slidably connected to the second flue gas channel (3); A lifting groove is formed in the inner wall of the second flue gas channel (3). A slide bar (332) is arranged in the lifting groove. Vibration plates (331) sleeved on the slide bar (332) are arranged on both sides of the plate catalyst (33). A limiting spring (333) sleeved on the slide bar (332) is arranged on one side of the vibration plate (331).

2. The flue gas denitration device for a cement kiln according to claim 1, wherein, The slideway (52) includes a first movable plate (521) rotatably connected to the inner wall of the flue gas filtration channel (5). A second movable plate (522) is rotatably arranged at one end of the first movable plate (521). A sleeve plate (523) is sleeved at one end of the second movable plate (522) away from the first movable plate (521). A lifting plate (524) is arranged on the sleeve plate (523). The lifting plate (524) is slidably connected to the filter screen (51). The brush plate (53) is fixed on the lifting plate (524). The movable end of the driving assembly (54) is connected to the lifting plate (524).

3. The flue gas denitrification device of a cement kiln according to claim 2, characterized in that, The driving assembly (54) comprises two driving wheels (541) rotatably arranged in the smoke filter channel (5); the driving wheels (541) are rotatably connected to the smoke filter channel (5) via a driving shaft (542); the two driving shafts (542) are connected to each other via a conveyor belt (546); a protrusion (543) is fixedly arranged on the driving wheel (541); a push plate (545) is fixedly arranged at the bottom end of the lifting plate (524); a limiting plate (544) is fixedly arranged at one end of the push plate (545) away from the lifting plate (524); a movable groove is provided on the surface of the limiting plate (544); the protrusion (543) slides in the movable groove.

Images