CN210425005U - Secondary air directional blowing device for embedded pipe in CFB boiler - Google Patents

Abstract

The utility model discloses a directional jetting device of buried pipe overgrate air in CFB boiler stove, the jetting pipe forms different jetting orientations according to the difference with the relative height of coal feed mouth. The utility model discloses with the coal feed mouth parallel and level or when the coal feed mouth lower part, transversely blow off coal dust flow of coal feed mouth spun, still can effectively sweep near the row cinder notch coal flow, prevent that the coal flow from not fully burning is discharged the stove promptly, reduce end sediment carbon content, go up overgrate air blowing direction configuration flexibility, its jetting branch plane projection and the staggered arrangement of overgrate air branch projection down, for the relative oxygen deficiency part coal flow air feed that the lower part rises, make the fuel in the stove realize the most probable space-time matching with the air, guarantee combustion efficiency.

Description

Secondary air directional blowing device for embedded pipe in CFB boiler

Technical Field

The utility model relates to a CFB boiler stove pipe laying overgrate air directional injection device.

Background

The existing CFB boiler is provided with an upper layer of secondary air and a lower layer of secondary air on two sides of a coal feeding port, the mass transfer effect of a large-section air column and a coal flow is poor, an oxygen-rich area and a coal-rich area exist, oxygen enrichment and fuel enrichment (including gas combustible substances and combustible carbon) cannot be optimally combined due to insufficient transverse movement capacity, and the large-section air column can only ascend in one way in each area until reaching a hearth outlet, particularly partially completes combustion reaction after meeting in a cyclone separator, namely the CFB boiler has the phenomenon of 'post combustion'. "afterburning" is a major issue that must be considered in boiler design.

Except that the fine particles which cannot be captured by the separator have the opportunity to re-enter the furnace for burning and releasing heat when the fly ash recycling system is arranged, the vast majority of the rest particles can only be expected to be exclamated and are wasted, and become the main stream of the carbon content of the fly ash. After the larger particles separated by the separator are returned to the hearth by the material returning device, part of the larger particles can not be returned to the hearth finally after being circularly combusted and ground for many times, and fly ash containing carbon is added.

In the existing mode of introducing secondary air, a plurality of secondary air ports are arranged above and below a coal feeding port on a front (rear) wall and on the left side and the right side of the coal feeding port, but the mode only can lead the secondary air to be basically strung along a channel with the minimum resistance and does not go to a place where people want to go, namely, the secondary air is fully mixed with particles in a rising main stream, and the air utilization of a key area is not ensured. Meanwhile, some coal particles which can participate in combustion fall to a slag discharge port and are discharged together with other waste slag, so that recycling is difficult to realize.

Under the above circumstances, how to ensure the uniform distribution of the secondary air in the section of the furnace chamber and realize the maximum mixed combustion of the secondary air and the pulverized coal is a problem to be solved urgently.

SUMMERY OF THE UTILITY MODEL

The technical problem solved by the utility model is to provide a secondary air directional direct current injection device under the pipe laying in the CFB boiler furnace.

The technical means adopted by the utility model are as follows.

A secondary air directional blowing device for a buried pipe in a CFB boiler is characterized in that a secondary air blowing structure is arranged in a hearth of the CFB boiler, the secondary air blowing structure comprises a plurality of blowing pipes which are suspended and inserted into the hearth, and the pipe wall of each blowing pipe is provided with a plurality of openings; the air injection pipes are respectively arranged in the middle of adjacent coal feeding ports, or are respectively arranged below the coal feeding ports or above the coal feeding ports, or are combined in any two of the three arrangement modes; the air injection pipes which are respectively arranged in the middle of the adjacent coal feeding ports horizontally and directionally inject secondary air through the openings, the air injection pipes which are respectively arranged below the coal feeding ports obliquely and directionally inject the secondary air obliquely upwards through the openings, and the air injection pipes which are respectively arranged above the coal feeding ports obliquely and/or obliquely inject the secondary air obliquely upwards and/or downwards through the openings.

The open holes on each air spraying pipe are arranged at intervals along the axial direction of the pipeline.

The blowing direction of the air injection pipe positioned obliquely below the coal feeding port forms an included angle with the tangential direction of the axial direction of the central axis of the air injection pipe to the lower side of the coal feeding port, and the angle range is within +/-10 degrees.

The opening of the side pipe of the blast pipe positioned at the outermost side is arranged in an outward encrypted manner and/or arranged in an encrypted manner near the slag discharge port.

When any two air injection pipe setting modes are combined, the projection of the opening blowing branch plane at the upper part relative to the projection of the opening blowing branch plane at the lower part is arranged in a staggered mode.

The air inlet ends of the plurality of air spraying pipes are all connected with a main pipe, a boundary jet air supply pipe is formed by branches on the main pipe, the boundary jet air supply pipe is connected with a plurality of abrasion-proof devices correspondingly installed on the air spraying pipes and used for supplying air to the abrasion-proof devices and forming a gaseous air film on the lower half circle of the corresponding air spraying pipe.

The air spraying pipe is in an oval shape with a horizontal short axis of the cross section, or the whole air spraying pipe is an eccentric variable cross-section pipeline with a horizontal bottom line, and the cross section of the air spraying pipe is gradually reduced from an air inlet end to an air spraying end.

The beneficial effects of the utility model are as follows.

1. The utility model discloses a set up overgrate air blast pipe cantilever form and stretch into furnace, the jetting has the direct current overgrate air of certain lateral displacement ability, and its jetting angle combines boiler coal supply mouth, row's cinder notch structural parameter to carry out corresponding design, blows off coal supply mouth spun buggy flow in addition transversely, makes oxygen content and fuel burning air distribution realize the most likely space-time matching, promotes combustion efficiency.

2. The utility model discloses after implementing, the air grid that the overgrate air formed has the effect of lifting to the coal breakage down, realizes the letter sorting function of big or small coal cinder, blocks the tiny particle buggy of whereabouts promptly and upwards flow once more, avoids too much useful buggy to get into the coal breakage pipe and wastes, promotes the fuel utilization ratio of boiler, except can directly reducing q3, q4 loss, can also increase dilute phase district fine particle concentration simultaneously, reinforce heat transfer efficiency, stabilize boiler area load capacity.

3. The utility model provides a spout the tuber pipe, its mode that mainly sets up the air film through spouting tuber pipe lower half week erodees the pipe wall and flue gas granule and flows completely isolated to realize the demand of pipe wall abrasionproof, also can adopt other conventional abrasionproof measures simultaneously. Even if the pipeline is partially worn through, air leakage occurs, and only the controlled direction and flow of the air flow are affected, and the furnace shutdown treatment is not needed.

4. The utility model provides a spout the tuber pipe and adopt the cantilever mode, the thermal energy is unrestricted, and the root temperature is low, and intensity is the highest, and requires to suit with the atress.

5. Because the improvement of boiler efficiency, the coal consumption reduces in unit time, the utility model discloses can directly reduce the emission of pollutant to improve the lime-ash (because of the carbon content reduces) quality.

6. The utility model discloses can reduce the secondary air fan pressure head to reduce the engineering and invest in and operate the power consumption just.

7. The coal flow close to the bottom slag discharge port or the side slag discharge port is blown away outwards from the slag discharge port, so that the coal flow is prevented from being discharged out of the furnace when the coal flow is not fully combusted, and the carbon content of the bottom slag is directly reduced.

8. The upper secondary air blowing branch and the lower secondary air blowing branch are arranged in a staggered mode, so that the carbon combustion is facilitated, and the reduction of NOx is facilitated.

Drawings

Fig. 1 is a schematic view of the overlooking angle of the secondary air pipe and the boundary jet air distribution system in the furnace of the present invention.

Fig. 2 is a schematic cross-sectional position diagram of the first embodiment of the arrangement of the secondary air blast pipes in the present invention.

Fig. 3 is a schematic cross-sectional position diagram of a second embodiment of the arrangement of the secondary air blast pipes in the present invention.

Fig. 4 is a schematic cross-sectional position diagram of a third embodiment of the arrangement of the secondary air blast pipes in the present invention.

Detailed Description

The utility model relates to an intubate formula overgrate air directional jetting device in CFB boiler stove.

In the embodiments shown in fig. 1 to 4, a overfire air injection structure is provided in the CFB boiler. Specifically, a plurality of secondary air injection pipes 3 inserted into the hearth 2 are arranged, a plurality of holes are formed in the pipe wall of each air injection pipe 3, and the holes are used for directionally injecting direct-current secondary air.

According to the actual condition of the boiler, adjacent air injection pipes can be selected to inject air obliquely upwards or obliquely downwards or alternatively obliquely upwards or obliquely downwards or horizontally towards two sides. Both of the above approaches are sufficient to power the coal flow with lateral displacement and provide the air required for combustion.

As shown in figure 1, the holes of the two side pipes positioned at the outermost side are arranged in an outward blowing direction in an openable and encrypted mode so as to provide enough lateral displacement power for the coal flow at the outermost side, and the holes near the slag discharge port can also be arranged in a dense mode so as to provide blowing power around the slag discharge port.

In the first embodiment shown in fig. 2, the air injection pipes 3 are respectively arranged between the coal feeding ports 1, and the air injection pipes are opened to inject air in a directional manner to the horizontal two sides.

In the second embodiment shown in fig. 3, the air injection pipe 3 is arranged obliquely below the coal feeding port 1, the opening is provided with air injection in an obliquely upward direction, the injection direction and the tangential line of the axial direction of the air injection pipe on the lower side of the coal feeding port 1 form an included angle, and the angle range is within +/-10 degrees.

As shown in fig. 4, in the third embodiment, the air injection pipe 3 is disposed above the coal feeding port 1, and for the upper secondary air in this embodiment, the injection direction of the air injection pipe 3 can be either upward or downward, so as not to damage the adjacent pipes.

When the air injection pipes 3 are combined in arrangement mode, the projection of the opening injection branch plane at the upper part and the projection of the opening injection branch plane at the lower part are arranged in a staggered mode so as to supply air to the relative oxygen-deficient coal flow with the ascending lower part.

The air injection pipe 3 is a pipe inserted into the hearth 2 in a cantilever shape, and the cross section of the air injection pipe can be in an oval shape with a horizontal short axis. An anti-abrasion device 4 is arranged on the lower half circumference of the air injection pipe 3, such as a gaseous air film, and is mainly used for preventing abrasion on the windward side below the secondary air injection pipe 3, or other structures capable of realizing abrasion prevention. The air inlet ends of the air injection pipes 3 are connected with a main pipe 5, and the main pipe can be branched to form 1 branch pipe 6 for supplying air to a plurality of square membrane devices to form gaseous air membranes.

No matter the air injection pipe is arranged in the mode, the ejected direct-current secondary air has the transverse displacement capacity and is transversely mixed with pulverized coal flow ejected from the coal feeding port, and the combustion efficiency is ensured.

Claims (7)

1. A CFB boiler in-furnace buried pipe secondary air directional blowing device is characterized in that a secondary air blowing structure is arranged in a CFB boiler furnace (2), the secondary air blowing structure comprises a plurality of blowing pipes (3) which are inserted into the furnace (2) in a suspended mode, and the pipe wall of each blowing pipe (3) is provided with a plurality of openings;

the air injection pipes (3) are respectively arranged in the middle of adjacent coal feeding ports, or obliquely below the coal feeding ports, or obliquely above the coal feeding ports, or a combination of any two of the three arrangement modes;

the secondary air is horizontally and directionally blown by the air injection pipes (3) which are respectively arranged in the middle of the adjacent coal feeding ports (1) through the openings, the secondary air is directionally blown by the air injection pipes (3) which are respectively arranged at the oblique lower parts of the coal feeding ports (1) towards the oblique upper parts through the openings, and the secondary air is blown by the air injection pipes (3) which are respectively arranged at the oblique upper parts of the coal feeding ports (1) towards the oblique upper parts and/or the oblique lower parts through the openings.

2. The CFB boiler in-furnace buried secondary air directional blowing device in accordance with claim 1, wherein the openings of each blowing pipe (3) are arranged at intervals along the axial direction of the duct.

3. The CFB boiler in-furnace buried secondary air directional injection device of claim 1, wherein the injection pipe (3) located obliquely below the coal feeding port (1) has an angle with the tangential direction of the lower side of the coal feeding port (1) along the axial direction of the axis of the injection pipe, and the angle is within +/-10 degrees.

4. The CFB boiler in-furnace buried pipe secondary air directional blowing device of claim 1, wherein the side pipe opening of the blowing pipe positioned at the outermost side is arranged in an outward encrypted manner and/or in an encrypted manner near a slag discharge port.

5. The CFB boiler in-furnace buried pipe secondary air directional blowing device of claim 1, characterized in that the blowing pipes (3) are arranged in any two combination modes, and the projection of the relatively upper open-hole blowing branch plane is staggered with the projection of the relatively lower open-hole blowing branch plane.

6. The CFB boiler in-furnace buried secondary air directional blowing device of claim 1, wherein the air inlet ends of the plurality of air injection pipes (3) are all connected with a main pipe (5), the main pipe (5) is branched to form a boundary jet air supply pipe (6), and the boundary jet air supply pipe (6) is connected with a plurality of wear prevention devices (4) correspondingly arranged on the air injection pipes (3) and used for supplying air to the wear prevention devices (4) and forming a gaseous air film on the lower half circumference of the corresponding air injection pipe (3).

7. The CFB boiler in-furnace buried pipe secondary air directional blowing device of claim 1, wherein the air injection pipe (3) is an ellipse with a horizontal minor axis of section, or the air injection pipe (3) is an eccentric variable-section pipeline with a horizontal bottom line as a whole, and the cross section of the eccentric variable-section pipeline gradually decreases from an air inlet end to an air injection end.

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