Rake type soot blower for cement kiln SCR (selective catalytic reduction) system and control method

Abstract

The invention discloses a rake type soot blowing device for a cement kiln SCR system and a control method, the rake type soot blowing device comprises a rake type soot blowing main air inlet pipe, a transverse rake outer pipe and a transverse rake inner pipe, and further comprises a first electromagnet, a second electromagnet, a first connecting flange, a second connecting flange, a third connecting flange, a flange seal and a control box which are connected with a reactor. The control box controls a built-in soot blowing precise control logic and is used for controlling the operation mode of the soot blowing system and the power-on and power-off of an electromagnet so as to realize the continuous and stable operation of the system; the structure of the inner sleeve and the outer sleeve is adopted, the position of the inner pipe of the transverse rake is changed through the electromagnet, so that compressed air is controlled to purge different positions, damage to a catalyst caused by single-position purge is effectively prevented, and meanwhile the purge area is effectively increased.

Description

Technical Field

[0001] The invention relates to the technical field of flue gas denitration, and in particular to a rake-type sootblower device and a control method for a cement kiln SCR system. Background Art

[0002] At present, the ultra-low emission control technology of nitrogen oxides in the cement industry is constantly improving, and more and more cement companies have adopted SCR denitrification systems. At present, the dust content in the SCR denitrification system of cement kilns is relatively high. For the denitrification system with high temperature and high dust, the dust content in the flue gas is about 80-120g / m3; for the denitrification system with medium temperature and medium dust, the dust content in the flue gas is about 60-80g / m3. Due to the large dust content in the flue gas, it is easy to cause the SCR denitrification catalyst to be blocked and cause the denitrification catalyst to be deactivated. In order to prevent the catalyst from accumulating dust and improve the denitrification efficiency, most cement kiln SCR denitrification systems currently use a sonic soot blower and a rake soot blower to blow soot together.

[0003] In the prior art, a rake soot blower is usually installed in the reactor. The position of extending and retracting compressed air for blowing is fixed and cannot be adjusted horizontally. Some parts cannot be blown, resulting in blind spots for blowing. The parts that cannot be blown first form dust accumulation, reducing the active surface area of ​​the catalyst and affecting the denitration efficiency of the system. In addition, under a certain soot blowing pressure for a long time, dust is easily accumulated in the pipe, resulting in a decrease in the soot blowing effect of the rake soot blower and catalyst blockage. Summary of the invention

[0004] Purpose of the invention: The present invention provides a rake-type sootblowing device and a control method for a cement kiln SCR system, which prevents damage to the catalyst caused by single-position blowing.

[0005] Technical solution: The present invention proposes a rake sootblowing device for a cement kiln SCR system, comprising a reactor, a rake sootblowing main air inlet pipe located in the reactor, a horizontal rake outer pipe fixedly connected to the rake sootblowing main air inlet pipe, a horizontal rake inner pipe located in the horizontal rake outer pipe, and a hose; electromagnets are fixed on both sides of the inner wall of the reactor, and the electromagnets are connected to a control box; one end of the hose is connected to the horizontal rake inner pipe, and the other end of the hose is connected to the rake sootblowing main air inlet pipe; a plurality of exhaust holes in a row are provided on the bottom of the horizontal rake outer pipe, and a plurality of fourth air holes in a row are provided on the bottom of the horizontal rake inner pipe, and the number of exhaust holes is greater than the number of fourth air holes; a plurality of fourth air holes (13) are connected to some exhaust holes.

[0006] Preferably, the cross rake inner tube is mechanically connected to the cross rake outer tube, and the cross rake inner tube is movable inside the cross rake outer tube.

[0007] Preferably, one end of the hose is connected to a second flange, the outer shell of the rake sootblowing main air inlet pipe is connected to the first flange, the outer shell of the horizontal rake outer pipe is connected to a third flange, the rake sootblowing main air inlet pipe and the horizontal rake outer pipe are fixedly connected through the first flange and the third flange, and the second flange is fixed through the first flange and the third flange.

[0008] Preferably, the first flange, the second flange and the third flange are sealed through end faces using flange seals (10).

[0009] Preferably, a first electromagnet and a second electromagnet are respectively placed on both sides of the inner wall of the reactor, and the first electromagnet and the second electromagnet are energized and de-energized under the automatic control of the PLC of the control box, thereby controlling the movement of the inner tube of the horizontal rake in the outer tube of the horizontal rake.

[0010] Preferably, the plurality of exhaust holes on the bottom of the horizontal rake outer tube include a plurality of air hole groups connected at the ends, each air hole group includes a first air hole, a second air hole and a third air hole, and the diameters of the first air hole, the second air hole and the third air hole are different; each air hole group corresponds to a fourth air hole; when the horizontal rake inner tube moves relative to the horizontal rake outer tube, each fourth air hole is only connected to the first air hole, the second air hole or the third air hole in the corresponding air hole group.

[0011] Preferably, the diameter of the fourth air hole on the inner tube of the cross rake is larger than that of the third air hole.

[0012] Preferably, the outer tube of the horizontal rake is a composite ceramic tube, and the inner tube of the horizontal rake is a metal tube.

[0013] A control method for a rake sootblower device of a cement kiln SCR system, wherein the control box controls a built-in sootblowing precision control logic, which is used to control the operation mode of the sootblowing system and the energization and de-energization of the electromagnet, so as to realize continuous and stable operation of the system; the horizontal rake inner tube has three working positions, when the first electromagnet is energized and the second electromagnet is de-energized, the horizontal rake inner tube is in working state 1: left position; when the first electromagnet is de-energized and the second electromagnet is energized, the horizontal rake inner tube is in working state 3: right position; when the first electromagnet is de-energized and the second electromagnet is energized, the horizontal rake inner tube is in working state 2: middle position.

[0014] Preferably, when in the left working state, the fourth air hole of the horizontal rake inner tube corresponds to the first air hole of the horizontal rake outer tube; when in the middle working state, the fourth air hole of the horizontal rake inner tube corresponds to the second air hole of the horizontal rake outer tube; when in the right working state, the fourth air hole of the horizontal rake inner tube corresponds to the third air hole of the horizontal rake outer tube.

[0015] Beneficial effect: The present invention provides a rake-type sootblowing device and a control method for a cement kiln SCR system. The device adopts an inner and outer outer casing structure, and changes the position of the inner tube of the horizontal rake through an electromagnet, thereby controlling the compressed air to blow at different positions, effectively preventing the damage to the catalyst caused by blowing at a single position, and effectively increasing the blowing area. The device uses an intelligent PLC control box to control the power on and off of the electromagnet, thereby driving the inner tube of the horizontal rake to move to the left, middle, and right positions. By changing the sizes of different sootblowing holes and the blowing pressure, the "pulsating" sootblowing is achieved, effectively preventing soot accumulation in the tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the rake type soot blower of the present invention;

[0017] Figure 2 This is a schematic diagram of the connection between the main air intake pipe and the horizontal rake pipe of the present invention;

[0018] Figure 3 It is a partial enlarged schematic diagram of the structural schematic diagram of the present invention at position I;

[0019] Figure 4 The positions of the pores in each working state of the present invention;

[0020] Figure 5 This is a schematic diagram of the structure of the outer tube of the horizontal rake of the present invention;

[0021] Figure 6 It is a cross-sectional view of the horizontal rake outer tube and the horizontal rake inner tube of the present invention. DETAILED DESCRIPTION

[0022] The present invention proposes a rake sootblowing device for a cement kiln SCR system, comprising a rake sootblowing main air intake pipe 1, a horizontal rake outer pipe 2 and a horizontal rake inner pipe 3, and also comprising a first electromagnet 5, a second electromagnet 6, a first connecting flange 7, a second connecting flange 8, a third connecting flange 9, a flange seal 10 and a control box 11 connected to a reactor 12; the sootblowing main air intake pipe 1, the horizontal rake outer pipe 2 and the horizontal rake inner pipe 3 are placed in the reactor 12, and the denitrification flue gas undergoes a denitrification reaction through the reactor 12; the rake sootblowing main air intake pipe 1 is connected to the outer shell of the horizontal rake outer pipe 2 through the first connecting flange 7, the second connecting flange 8, the third connecting flange 9 and the flange seal 10, the horizontal rake inner pipe 3 is connected to the hose 4 through a flange, one end of the hose 4 is the second connecting flange 8, the second connecting flange 8 is fixed by the first connecting flange 7 and the third connecting flange 9, the first connecting flange 7 and the second connecting flange 9 are connected The flange 8 is sealed by a flange seal 10 to prevent air leakage; the horizontal rake outer tube 2 is a ceramic tube with a plurality of air holes at the bottom of the tube, which are the first air hole 14, the second air hole 15 and the third air hole 16 from small to large, and the first air hole 14, the second air hole 15 and the third air hole 16 are circular holes or waist-shaped holes; the horizontal rake inner tube 3 is a metal tube, which can be an iron tube, and the bottom of the horizontal rake inner tube 3 is provided with a plurality of fourth air holes 13, and the size of the fourth air hole 13 is slightly larger than the third air hole 16 of the horizontal rake outer tube; the control box 11 controls the built-in soot blowing precision control logic, which is used to control the operation mode of the soot blowing system and the power on and off of the electromagnet, so as to realize the continuous and stable operation of the system; the first electromagnet 5 and the second electromagnet 6 are respectively placed on both sides of the horizontal rake tube, and the two electromagnets are controlled to be powered on and off by the control box 11. By changing the power on and off of the two electromagnets, the horizontal rake inner tube 3 stays in the left, middle and right positions.

[0023] The sootblower drives the gear rack through a motor or hydraulic drive, thereby pushing the rake sootblower main air intake pipe 1 to move forward and backward along the axial direction. There is a small gap between the horizontal rake inner tube 3 and the horizontal rake outer tube 2, and the horizontal rake inner tube 3 can move laterally in the horizontal rake outer tube 2. The horizontal rake outer tube 2 and the horizontal rake inner tube 3 are connected by mechanical matching. There is a keyway in the horizontal rake outer tube 2 and a guide key on the outside of the horizontal rake inner tube 3, which plays a positioning and guiding role, is convenient for the installation of the inner and outer tubes, and is convenient for left and right movement.

[0024] The first electromagnet 5 and the second electromagnet 6 are provided on the inner walls on both sides of the reactor 12, and are located on both sides of the horizontal rake inner tube 3. The first electromagnet 5 and the second electromagnet 6 are energized and de-energized under the automatic control of the PLC of the control box 11, so that the horizontal rake inner tube 3 moves. The control box 11 controls the built-in soot blowing precision control logic, which is used to control the operation mode of the soot blowing system and the energization and de-energization of the electromagnets, so as to realize the continuous and stable operation of the system. Control method of sootblowing device: the horizontal rake inner tube 3 has three working positions. When the first electromagnet 5 is energized and the second electromagnet 6 is de-energized, the horizontal rake inner tube 3 is in working state 1: left position. At this time, the fourth air hole 13 of the horizontal rake inner tube 3 corresponds to the first air hole 14 of the horizontal rake outer tube 2 to form a sootblowing hole; when the first electromagnet 5 is de-energized and the second electromagnet 6 is energized, the horizontal rake inner tube 3 is in working state 3: right position. The fourth air hole 13 of the horizontal rake inner tube 3 corresponds to the second air hole 15 of the horizontal rake outer tube 2 to form a sootblowing hole; when the first electromagnet 5 is de-energized and the second electromagnet 6 is energized, the horizontal rake inner tube 3 is in working state 2: middle position. The fourth air hole 13 of the horizontal rake inner tube 3 corresponds to the third air hole 16 of the horizontal rake outer tube 2 to form a sootblowing hole. When the horizontal rake inner tube 3 is in different working positions, the movement of the rake sootblower's air blowing in the left, middle and right positions effectively increases the working range of sootblowing by changing the sizes of different sootblowing holes, thereby achieving accurate and effective sootblowing.

[0025] The present invention adopts an inner and outer sleeve structure, and changes the position of the inner tube 3 of the horizontal rake through an electromagnet, thereby controlling the compressed air to blow at different positions, effectively preventing the damage to the catalyst caused by blowing at a single position, and effectively increasing the blowing area; an intelligent PLC control box is used to control the power on and off of the electromagnet, thereby driving the inner tube of the horizontal rake to move to the left, middle and right positions, and by changing the sizes of different soot blowing holes and the blowing pressure, "pulsating" soot blowing is achieved, effectively preventing soot accumulation in the tube.

Claims

1. A rake-type sootblower for a cement kiln SCR system, characterized in that: It comprises a reactor (12), a rake-type sootblowing main air intake pipe (1) located in the reactor (12), a horizontal rake outer pipe (2) fixedly connected to the rake-type sootblowing main air intake pipe (1), a horizontal rake inner pipe (3) located in the horizontal rake outer pipe (2), and a hose (4); electromagnets are fixed on both sides of the inner wall of the reactor (12), and the electromagnets are connected to a control box (11); one end of the hose (4) is connected to the horizontal rake inner pipe (3), and the other end of the hose (4) is connected to the rake-type sootblowing main air intake pipe (1); a plurality of exhaust holes in a row are provided on the bottom of the horizontal rake outer pipe (2), and a plurality of fourth air holes (13) in a row are provided on the bottom of the horizontal rake inner pipe (3), and the number of exhaust holes is greater than the number of fourth air holes (13); a plurality of fourth air holes (13) are connected to some of the exhaust holes.

2. The rake-type sootblowing device for the cement kiln SCR system according to claim 1, characterized in that: The cross-rake inner tube (3) is mechanically connected to the cross-rake outer tube (2), and the cross-rake inner tube (3) can move inside the cross-rake outer tube (2).

3. The rake-type sootblowing device for the cement kiln SCR system according to claim 1, characterized in that: One end of the hose (4) is connected to a second flange (8), the outer shell of the rake-type sootblowing main air inlet pipe (1) is connected to the first flange (7), the outer shell of the horizontal rake outer pipe (2) is connected to the third flange (9), the rake-type sootblowing main air inlet pipe (1) and the horizontal rake outer pipe (2) are fixedly connected via the first flange (7) and the third flange (9), and the second flange (8) is fixed via the first flange (7) and the third flange (9).

4. The rake-type sootblowing device for the cement kiln SCR system according to claim 3, characterized in that: The first flange (7), the second flange (8) and the third flange (9) are sealed through end faces using flange seals (10).

5. The rake-type sootblowing device for the cement kiln SCR system according to claim 2, characterized in that: A first electromagnet (5) and a second electromagnet (6) are respectively placed on both sides of the inner wall of the reactor (12); the first electromagnet (5) and the second electromagnet (6) are energized and de-energized under the automatic control of the PLC of the control box (11), thereby controlling the movement of the inner tube (3) of the horizontal rake in the outer tube (2).

6. The rake-type sootblowing device for the cement kiln SCR system according to claim 1, characterized in that: The bottom of the horizontal rake outer tube (2) is provided with a plurality of exhaust holes, including a plurality of air hole groups connected at the end, each air hole group comprising a first air hole (14), a second air hole (15) and a third air hole (16), the first air hole (14), the second air hole (15) and the third air hole (16) having different diameters; each air hole group corresponds to a fourth air hole (13); when the horizontal rake inner tube (3) moves relative to the horizontal rake outer tube (2), each fourth air hole (13) is only connected to the first air hole (14), the second air hole (15) or the third air hole (16) in the corresponding air hole group.

7. The rake-type sootblowing device for the cement kiln SCR system according to claim 6, characterized in that: The diameter of the fourth air hole (13) on the cross rake inner tube (3) is larger than that of the third air hole (16).

8. The rake-type sootblowing device for a cement kiln SCR system according to claim 1, characterized in that: The horizontal rake outer tube (2) is a composite ceramic tube, and the horizontal rake inner tube (3) is a metal tube.

9. A control method for a rake sootblower device for a cement kiln SCR system according to any one of claims 1 to 8, characterized in that: The control box (11) controls the built-in sootblowing precision control logic, which is used to control the operation mode of the sootblowing system and the power on and off of the electromagnet, so as to realize continuous and stable operation of the system; the horizontal rake inner tube (3) has three working positions. When the first electromagnet (5) is powered and the second electromagnet (6) is powered off, the horizontal rake inner tube (3) is in working state 1: left position; when the first electromagnet (5) is powered off and the second electromagnet (6) is powered on, the horizontal rake inner tube (3) is in working state 3: right position; when the first electromagnet (5) is powered off and the second electromagnet (6) is powered on, the horizontal rake inner tube (3) is in working state 2: middle position.

10. The control method for a rake-type sootblower of a cement kiln SCR system according to claim 9, characterized in that: When in the left working state, the fourth air hole (13) of the horizontal rake inner tube (3) corresponds to the first air hole (14) of the horizontal rake outer tube (2); when in the middle working state, the fourth air hole (13) of the horizontal rake inner tube (3) corresponds to the second air hole (15) of the horizontal rake outer tube (2); when in the right working state, the fourth air hole (13) of the horizontal rake inner tube (3) corresponds to the third air hole (16) of the horizontal rake outer tube (2).

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