CN111271725A - Anti-blocking system for multi-stage mixed flow primary air pipe - Google Patents

Abstract

The invention relates to a multistage mixed flow primary air pipe anti-blocking system, which adopts the technical scheme that the system comprises a primary air pipe, wherein the primary air pipe is of a circular hollow tubular structure formed by sequentially connecting a primary air pipe horizontal section, an elbow transition section and a primary air pipe vertical section, the primary air pipe horizontal section is internally provided with a primary cyclone, a secondary mixer and a tertiary mixer in sequence along the conveying direction of the pulverized coal, the bottom of the junction of the primary air pipe horizontal section and the elbow transition section is provided with a powder accumulation collecting port which is communicated up and down, and the powder accumulation collecting port is connected with a pulverized coal collecting device which extends downwards. The coal powder collecting device is arranged at the junction of the horizontal section of the primary air pipe and the transition section of the elbow to collect the accumulated powder.

Description

Anti-blocking system for multi-stage mixed flow primary air pipe

Technical Field

The invention relates to a multistage mixed flow primary air pipe anti-blocking system.

Background

In a coal-fired boiler, most of the existing boilers are pulverized coal boilers, hot air is needed to convey pulverized coal, and the pulverized coal making system comprises a positive-pressure pulverized coal making system and a negative-pressure pulverized coal making system and mainly aims at operating the boilers with four tangential corners. When carrying out the buggy with hot-blast, because the powder pipe is longer, especially when the horizontal segment position, the buggy is because the action of gravity, thick buggy can deposit and flow in the powder pipe lower part, when the tuber pipe that the coal pulverizer belongs to is in the eminence in operation, when entering furnace burning soon, all there is one section vertical rising section, when this position, the thick buggy of deposit in the lower part is because heavier, deposit easily in this vertical segment lower part elbow position when the vertical rising section, gather here, cause the through-flow area to reduce, tuber pipe internal resistance increases, thereby cause the jam to begin to appear in this powder pipe other positions, the coal seam that generally has the jam is D, E, F high-rise positions, the general vertical segment of lower floor coal seam is shorter, can not have a large amount of buggy to pile up, cause the powder pipe jam, influence unit safe operation. Many powder pipes can not be processed after being blocked, and the blocked part of the powder pipe can only be cut off once after the coal mill is stopped, so that the accumulated coal powder is removed, which is very troublesome. Generally, before the hot-state operation, four powder pipes of one coal mill are subjected to a leveling test, the air speeds of the four powder pipes are adjusted to be within +/-5%, the air speeds of the four powder pipes are influenced after the powder pipes are partially blocked, the deviation of the air speeds of four corners is large, the deviation of powder quantity is large, combustion deflection is caused, and the operation safety of a unit is influenced. Therefore, improvement and innovation thereof are imperative.

Disclosure of Invention

In view of the above situation, the present invention aims to provide an anti-blocking system for a multi-stage mixed flow primary air duct, which can effectively solve the problem that the primary air duct is blocked by powder accumulation in the primary air duct.

The technical scheme of the invention is as follows:

a multi-stage mixed flow primary air pipe anti-blocking system comprises a primary air pipe, wherein the primary air pipe is formed by sequentially connecting a primary air pipe horizontal section, an elbow transition section and a primary air pipe vertical section together to form a circular hollow tubular structure, a primary cyclone, a secondary mixer and a tertiary mixer are sequentially arranged in the primary air pipe horizontal section along the conveying direction of pulverized coal, a vertically through accumulated powder collecting port is formed at the bottom of the junction of the primary air pipe horizontal section and the elbow transition section, a pulverized coal collecting device extending downwards is connected to the accumulated powder collecting port, the pulverized coal collecting device is connected to the lower end of the accumulated powder collecting port and is communicated with a dust collecting funnel and a pulverized coal storage tank fixedly connected to the lower part of the dust collecting funnel, the dust collecting funnel is an integrated structure consisting of a funnel body in a truncated cone-shaped tubular structure and an extending pipeline in a cylindrical tubular structure, the large opening end of the funnel body is positioned under the accumulated powder collecting port and is connected with the outer wall of the primary air pipe in, the end of the small mouth of funnel body links to each other with extension pipeline upper junction, the lower part of extension pipeline stretches into its inner chamber from the upper end of buggy holding vessel, the lower extreme edge that stretches into partial extension pipeline lower junction one side is provided with pivoted round pin axle, it extends and follows round pin axle pivoted removable cover to sell epaxial being fixed with orientation extension pipeline lower junction opposite side, it has the inside and outside slip stroke hole that link up to open on the lateral wall of the buggy holding vessel of keeping away from removable cover one side, it extends and stretches out the balancing pole of buggy holding vessel from the slip stroke hole to sell epaxial being fixed with orientation, when the balancing pole is located the lower extreme position in slip stroke hole, removable cover covers the lower junction of sealed extension pipeline completely, when the balancing pole upwards slided along the slip stroke hole, removable cover's free end downward upset breaks away from extension pipeline lower junction, the extension pipeline lower junction is opened.

Preferably, the lower part of the coal powder storage tank is provided with an ash discharge port communicated with the inner cavity of the coal powder storage tank, a plug is screwed on the ash discharge port, and a pull-type ash bearing plate is arranged on the side wall of the coal powder storage tank above the plug.

Preferably, the ash discharge port threaded connection of end cap and buggy holding vessel lower part can be sealed with the ash discharge port shutoff, open the pull passageway that has inside and outside to link up on the buggy holding vessel lateral wall of end cap top, hold the hawk and arrange in the pull passageway and slide along the pull passageway, be fixed with the slot that corresponds with holding the hawk tip on the offside buggy holding vessel inner wall of pull passageway, the pulling holds the hawk and stretches into the buggy holding vessel and insert the slot after, hold the hawk and cover buggy holding vessel inner chamber cross section, stretch out and be fixed with the handle on the outside hawk tip that holds of buggy holding vessel.

Preferably, a balancing weight is hung on the balancing rod extending out of the pulverized coal storage tank.

The invention has novel and unique structure, simplicity, reasonableness and simple operation, the primary air and the coal dust are subjected to continuous rotational flow mixing by arranging the first-stage, second-stage and third-stage flow mixers in the horizontal section of the primary air pipe, the coal dust is ensured not to sink and accumulate to the maximum extent, and finally the coal dust is sent into the vertical section of the primary air pipe through the elbow transition section, the coal dust collecting device is arranged at the junction of the horizontal section of the primary air pipe and the elbow transition section to collect the accumulated powder, the whole system can effectively solve the problem of coal dust blockage of the primary air pipe under the condition of combined use of the flow mixers and the coal dust collecting device, thereby being an innovation on the anti-blockage structure of the primary air pipe.

Drawings

Fig. 1 is a cross-sectional view of the present invention.

Fig. 2 and 3 are sectional views of the pulverized coal collecting apparatus of the present invention, in which fig. 2 shows a closed state of the movable cover and fig. 3 shows an open state of the movable cover.

FIG. 4 is a schematic structural view of a primary swirler and a secondary mixer of the present invention.

FIG. 5 is a schematic structural view of a three-stage flow mixer of the present invention.

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

As shown in figures 1-5, the invention comprises a primary air pipe, the primary air pipe is a circular hollow tubular structure formed by sequentially connecting a primary air pipe horizontal section 1, an elbow transition section 2 and a primary air pipe vertical section 3, a primary cyclone 4a, a secondary mixer 4b and a tertiary mixer 4c are sequentially arranged in the primary air pipe horizontal section 1 along the coal powder conveying direction, a vertically through accumulated powder collecting port 17 is arranged at the bottom of the junction of the primary air pipe horizontal section and the elbow transition section, a coal powder collecting device extending downwards is connected on the accumulated powder collecting port 17, the coal powder collecting device is connected at the lower end of the accumulated powder collecting port and is communicated with an ash receiving funnel 6 and a coal powder storage tank 7 fixedly connected at the lower part of the ash receiving funnel, the ash receiving funnel 6 is an integrated structure formed by a funnel body 6a in a round table tubular structure and an extension pipeline 6b in a cylindrical tubular structure, the large-opening end of the funnel body 6a is positioned under the accumulated powder collecting opening and is hermetically connected with the outer wall of the primary air pipe, the small-opening end of the funnel body 6a is connected with the upper opening of the extension pipeline 6b, the lower part of the extension pipeline 6b extends into the inner cavity of the coal powder storage tank 7 from the upper end of the coal powder storage tank, the lower end edge of one side of the lower opening of the extension pipeline is provided with a rotating pin shaft 10, a movable cover plate 11 which extends towards the other side of the lower opening of the extension pipeline and rotates along with the pin shaft is fixed on the pin shaft 10, the side wall of the coal powder storage tank far away from one side of the movable cover plate is provided with a sliding stroke hole 13 which is communicated with the inside and the outside, a balance rod 12 which extends towards one side far away from the movable cover plate and extends out of the coal powder storage tank from the sliding stroke hole is fixed on the pin shaft 10, when the balance rod 12 is positioned at the lower limit position of the sliding, the free end of the movable cover plate 11 is turned downwards to be separated from the lower edge of the extension pipeline, and the lower opening of the extension pipeline 6b is opened.

The big mouth end of the funnel body 6a can be welded and fixed with the outer wall of the primary air pipe, and the pulverized coal storage tank 7 is welded and fixed with the outer wall of the extension pipeline 6 b.

In order to ensure the using effect, the lower part of the coal powder storage tank 7 is provided with an ash discharge port communicated with the inner cavity of the coal powder storage tank, a plug 8 is screwed on the ash discharge port, and a pull-type ash bearing plate 9 is arranged on the side wall of the coal powder storage tank 7 above the plug 8.

The utility model discloses a coal dust storage tank, including end cap 8, buggy holding tank 7, end cap 8 and buggy holding tank 7, can be sealed with the shutoff of ash discharge mouth, open on 7 lateral walls of buggy holding tank above end cap 8 the pull passageway that link up inside and outside, hold hawk 9 and arrange in the pull passageway and slide along the pull passageway, be fixed with the slot 9b that corresponds with holding hawk tip on the offside buggy holding tank inner wall of pull passageway, the pulling holds hawk and stretches into buggy holding tank and insert the slot after, hold hawk cover buggy holding tank inner chamber cross section, stretch out and be fixed with handle 9a on the outside hawk tip of buggy holding tank, after the defeated powder is accomplished, place the coal charging bag in buggy holding tank below, lift the end cap rotation off, then will hold hawk pull open, the buggy flows in the coal bag, it can to carry away the buggy.

The primary cyclone 4a and the secondary flow mixer 4b have the same structure and respectively comprise 4 first cyclone blades 41 uniformly distributed on the inner wall of the horizontal section of the primary air pipe, and a first cyclone channel 41 is formed by a gap between every two adjacent first cyclone blades.

The third-stage mixer 5 comprises 8 second swirl vanes 51 uniformly distributed on the inner wall of the horizontal section of the primary air pipe, and a second swirl passage 51 is formed by a gap between every two adjacent second swirl vanes.

The maximum height of the first cyclone blade 41 is 1/5 of the inner diameter of the horizontal section of the primary air pipe, and the included angle between the connecting line of the head end point and the tail end point of the central line of the connecting section of the first cyclone blade and the inner wall of the horizontal section of the primary air pipe and the axis of the horizontal section of the primary air pipe is 15-25 degrees;

the maximum height of the second cyclone blades 51 is 1/4 of the inner diameter of the horizontal section of the primary air pipe, and the included angle between the connecting line of the head end point and the tail end point of the central line of the connecting section of the second cyclone blades and the inner wall of the horizontal section of the primary air pipe and the axis of the horizontal section of the primary air pipe is 15-25 degrees;

one-level, the second grade swirler design is for only four at primary air pipe inner wall installation blades, the effect is when producing the whirl after the installation, increase pipeline internal resistance relatively less, mix the back through second grade swirler whirl, the tertiary swirler whirl of 8 blades of rethread mixes, finally send into the vertical section of primary air pipe through the elbow changeover portion, make buggy and primary air misce bene, guarantee the normal transport of buggy, do not influence the economic nature of unit operation when not laying dust yet.

One end of the primary air pipe horizontal section 1, which is far away from the primary air pipe vertical section, is connected with an outlet of a coal mill, the distance between the primary cyclone 4a and the outlet of the coal mill is three times of the inner diameter of the primary air pipe horizontal section, the secondary flow mixer 4b is positioned in the middle of the primary air pipe horizontal section, and the distance between the tertiary flow mixer 4c and the central line of the primary air pipe vertical section is three times of the inner diameter of the primary air pipe horizontal section. The distance calculation takes the centers of the first-stage, second-stage and third-stage cyclones as a reference. As the horizontal section of the primary air pipe is longer, the rotational flow strength of each flow mixer is weakened a lot after the flow mixer passes through the pipe diameter length of 5 times, and the rotational flow mixer is installed in 3 stages. As shown in the arrow direction of figure 1, the primary air and the coal powder form a spiral flow after passing through the primary cyclone, the spiral flow is gradually converted into a direct flow along with the forward movement of the mixed air, and then continuously forms the spiral flow through the secondary and tertiary flow mixers in sequence, so that the primary air and the coal powder are subjected to continuous spiral flow mixing, and the coal powder is prevented from sinking and accumulating to the maximum extent.

A balancing weight 14 is hung on the balancing pole extending out of the pulverized coal storage tank. The lower part of the balancing pole extending out of the pulverized coal storage tank is evenly provided with a plurality of balancing weight hooks 15 along the length direction, and balancing weights 14 are hung on the balancing weight hooks 15. Through the quantity of balancing weight and adjust balancing weight along balancing pole length direction front and back position relation and adjust removable cover ponding volume and open-ended relation, when the increase of balancing weight quantity or when keeping away from round pin axle direction removal towards promptly, removable cover needs bigger ponding volume just can overturn downwards, and the opening when reaching the balance reduces along with the weight is kept away from, when the ponding volume reaches open-ended weight, the removable cover upset is opened, the buggy falls into the buggy holding vessel inner chamber from extending the pipeline end opening, pile up on holding the hawk.

When the invention is used, primary air and coal powder enter the horizontal section of the primary air pipe, then form spiral flow through the primary swirler, the spiral flow is gradually weakened along with the advance of mixed air, and then continuously form spiral flow through the second-stage and third-stage flow mixers, the primary air and the coal powder are continuously mixed in a swirling manner, so that the coal powder is prevented from sinking and accumulating to the maximum extent, and finally sent into the vertical section of the primary air pipe through the elbow transition section, and when the angle of a separator of a pulverizing system is not suitable or the grinding roller and the grinding disc are seriously worn, the fineness of the coal powder deviates from the design value to a larger degree, and when the horizontal section of the primary air pipe is layered more seriously, if the fineness of the coal powder is thicker, the problem can not be solved only by the swirler, therefore, the system is provided with a coal powder collecting device at the junction of the horizontal section of the primary air pipe and the elbow transition section, and 16 behind a powder accumulation collecting port, the deposition in the primary air pipe horizontal segment in long-pending powder collection mouth the place ahead is directly blown in by a wind and is connect grey funnel, the buggy falls into removable cover, when the deposition reaches the opening weight of counter weight, removable cover upset is opened, the buggy falls into buggy holding vessel inner chamber from extending the pipeline end opening, pile up on holding the hawk, defeated powder is accomplished the back, place the dress coal bag in buggy holding vessel below, lift the end cap rotation off, then will hold the hawk and pull open, the buggy flows in the coal bag, can with the buggy transport away. The whole system can effectively solve the problem of coal dust blockage of the primary air pipe under the condition of combined use of the flow mixer and the coal dust collecting device. Under normal conditions, the power plant is generally blocked once in a month period, a primary wind speed online device or a static pressure measuring point is installed in the power plant to monitor the condition of a primary wind pipe, and the wind pipe is blocked when the wind speed is low or the static pressure is high and the measuring point display is problem-free. By looking at the static pressure curve, the increase in static pressure appears to increase steadily, whereby the blockage is more and more severe after a slight blockage has occurred, usually at a month period, and it is not possible to operate normally. This situation can be avoided if the clogged coal dust is discharged in time. The system can effectively solve the problem after being installed, and can not be blocked within one operation period, namely 1-2 years through practical application. Its novel structure is unique, and is simple reasonable, reform transform on original primary air pipe can, its convenient to use, effectual, with low costs, the practicality is strong, is that the structural innovation is prevented blockking up by the primary air pipe, can effectively solve the problem that the long-pending powder of primary air pipe blockked up the primary air pipe, has good social and economic benefits.

Claims (7)

1. A multi-stage mixed flow primary air pipe anti-blocking system comprises a primary air pipe, wherein the primary air pipe is formed by sequentially connecting a primary air pipe horizontal section (1), an elbow transition section (2) and a primary air pipe vertical section (3) to form a circular hollow tubular structure, and is characterized in that a primary cyclone (4a), a secondary mixer (4b) and a tertiary mixer (4c) are sequentially arranged in the primary air pipe horizontal section (1) along the conveying direction of coal powder, a powder accumulation collecting port (17) which is communicated up and down is formed in the bottom of the junction of the primary air pipe horizontal section and the elbow transition section, a coal powder collecting device which extends downwards is connected to the powder accumulation collecting port (17), the coal powder collecting device is connected to the lower end of the powder accumulation collecting port, and a dust collecting funnel (6) and a coal powder storage tank (7) which are fixedly connected to the lower part of the dust collecting funnel are communicated with, the ash receiving funnel (6) is an integrated structure consisting of a funnel body (6a) with a truncated cone-shaped tubular structure and an extension pipeline (6b) with a cylindrical tubular structure, the large opening end of the funnel body (6a) is positioned under the accumulated powder collecting opening and is hermetically connected with the outer wall of a primary air pipe, the small opening end of the funnel body (6a) is connected with the upper opening of the extension pipeline (6b), the lower part of the extension pipeline (6b) extends into the inner cavity of the pulverized coal storage tank (7) from the upper end of the pulverized coal storage tank, the lower end of one side of the lower opening of the extension pipeline is provided with a rotating pin shaft (10), a movable cover plate (11) which extends towards the other side of the lower opening of the extension pipeline and rotates along with the pin shaft is fixed on the pin shaft (10), the side wall of the pulverized coal storage tank far away from one side of the movable cover plate is provided with a sliding stroke hole (13) which is communicated with the inside and outside, a balancing rod (12) which extends towards one side far away from, when the balance rod (12) is located at the lower limit position of the sliding stroke hole (13), the movable cover plate (11) completely covers the lower opening of the sealed extension pipeline (6b), and when the balance rod (12) slides upwards along the sliding stroke hole (13), the free end of the movable cover plate (11) is downwards overturned to be separated from the lower edge of the extension pipeline, and the lower opening of the extension pipeline (6b) is opened.

2. The multistage mixed flow primary air pipe anti-blocking system according to claim 1, wherein an ash discharge port communicated with an inner cavity of the coal dust storage tank (7) is formed in the lower portion of the coal dust storage tank, a plug (8) is screwed on the ash discharge port, and a pull-out ash bearing plate (9) is arranged on the side wall of the coal dust storage tank (7) above the plug (8).

3. The multistage mixed flow primary air pipe anti-blocking system according to claim 2, characterized in that the plug (8) is in threaded connection with the ash discharge port at the lower part of the pulverized coal storage tank (7), the ash discharge port can be sealed in a blocking manner, a pull channel which is through from inside to outside is formed in the side wall of the pulverized coal storage tank (7) above the plug (8), the ash bearing plate (9) is arranged in the pull channel and slides along the pull channel, a slot (9b) corresponding to the end part of the ash bearing plate is fixed on the inner wall of the pulverized coal storage tank opposite to the pull channel, the ash bearing plate covers the cross section of the inner cavity of the pulverized coal storage tank after being stretched into the pulverized coal storage tank and inserted into the slot, and a pull handle (9a) is fixed on the end part of the ash bearing plate stretching out of the pulverized coal.

4. The multi-stage mixed flow primary air pipe anti-blocking system according to claim 1, wherein the primary cyclone (4a) and the secondary mixer (4b) have the same structure, and each of the primary cyclone (4a) and the secondary mixer comprises 4 first cyclone vanes (41) uniformly distributed on the inner wall of the horizontal section of the primary air pipe, and gaps between every two adjacent first cyclone vanes form first cyclone channels (41).

5. The multistage mixed flow primary air pipe anti-blocking system according to claim 1, wherein the tertiary mixed flow device (5) comprises 8 second swirl vanes (51) uniformly distributed on the inner wall of the horizontal section of the primary air pipe, and the gap between every two adjacent second swirl vanes forms a second swirl channel (51).

6. The multi-stage mixed flow primary air pipe anti-blocking system according to claim 1, wherein one end of the primary air pipe horizontal section (1) far away from the primary air pipe vertical section is connected with an outlet of a coal mill, the distance between a primary cyclone (4a) and the outlet of the coal mill is three times of the inner diameter of the primary air pipe horizontal section, a secondary mixed flow device (4b) is positioned in the middle of the primary air pipe horizontal section, and the distance between a tertiary mixed flow device (4c) and the center line of the primary air pipe vertical section is three times of the inner diameter of the primary air pipe horizontal section.

7. The multistage mixed flow primary air pipe anti-blocking system according to claim 1, wherein a balancing weight (14) is hung on a balancing pole extending out of the pulverized coal storage tank.

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