A metal expansion joint to prevent slag from flowing out of a drum slag cooler

Abstract

This invention relates to a metal expansion joint for preventing slag flow from flowing freely in a drum slag cooler. The joint includes an inner tube, an expansion mechanism, and a gas discharge mechanism. The expansion mechanism is sleeved outside the inner tube. The inner tube has one or more vent holes connected to the inlet of the gas discharge mechanism. The gas discharge mechanism is located between the inner tube and the expansion mechanism and extends out from within the expansion mechanism. The portion of the gas discharge mechanism extending out from the expansion mechanism has a vent. This invention removes gas from the high-temperature ash particles through the gas discharge mechanism, reducing its gas content and significantly decreasing its fluidity. This effectively blocks the initial cause of slag flow from flowing freely in the drum slag cooler and prevents instantaneous emptying of the slag discharge pipe under abnormal boiler operating conditions, thus protecting surrounding equipment and personnel from hot slag damage.

Description

Technical Field

[0001] This invention relates to the field of metal expansion joints, and in particular to a metal expansion joint for preventing the free flow of slag in a drum slag cooler. Background Technology

[0002] The furnace of a circulating fluidized bed boiler is under slight positive pressure, with a pressure of about 7-10 kPa. In addition, when a circulating fluidized bed boiler burns lignite or a large proportion of coal slurry, the resulting ash particles are extremely fine and have super-fluidity (close to liquid fluidity) in the hot state, thus forming a large gas content in the dense phase zone. This high-temperature ash with a large gas content of about 1000°C must be cooled to 150°C in the drum cooler body through a high-temperature resistant ash discharge pipe, ash valve, and metal expansion joint before being transported to the ash silo for storage and treatment by belt or chain bucket conveyor.

[0003] If the slag cooler is blocked and then suddenly becomes unblocked by gravity or by manual slag removal, if the highly fluid, high-air-content ash-slag gas-solid two-phase flow cannot form a reliable material column seal at the bottom of the high-temperature slag discharge pipe inside the drum slag cooler, even if the drum slag cooler is stopped (or running at low speed), a large amount of high-temperature ash slag that has not been sufficiently cooled will still flow directly to the outlet of the drum slag cooler. This phenomenon is called the slag flow of the drum slag cooler.

[0004] If a drum slag cooler experiences slag overflow, the high-temperature ash and slag that has not been cooled will enter the downstream equipment of the cooler, causing damage to the downstream equipment. The high-temperature flue gas, carrying high-temperature ash and slag, will also leak out from the sealed ends of the cooler cylinder, damaging maintenance personnel, surrounding electrical equipment, and downstream conveying equipment, posing a great hazard. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a metal expansion joint to prevent slag from flowing freely in a drum slag cooler. The expansion joint removes gas from the high-temperature ash granular flow through a gas discharge mechanism, thereby preventing the problem of slag flowing freely in the drum slag cooler and protecting surrounding equipment and personnel from hot slag damage.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A metal expansion joint for preventing slag from flowing out of a drum slag cooler includes an inner tube, an expansion mechanism, and a gas discharge mechanism. The expansion mechanism is sleeved outside the inner tube. The inner tube has one or more vent holes, which are connected to the inlet of the gas discharge mechanism. The gas discharge mechanism is located between the inner tube and the expansion mechanism and extends out of the expansion mechanism. The portion of the gas discharge mechanism extending out of the expansion mechanism has a vent.

[0008] Furthermore, the exhaust mechanism is an exhaust pipe, which is sleeved outside the inner pipe. One end of the exhaust pipe is sealed to the portion of the inner pipe located inside the expansion mechanism, and the other end of the exhaust pipe is sealed to the portion of the inner pipe located outside the expansion mechanism.

[0009] Furthermore, the exhaust port is located on the inner tube, on the side wall inside the exhaust pipe.

[0010] Furthermore, the exhaust pipe extends from the bottom end of the expansion mechanism.

[0011] Furthermore, the exhaust pipe and the inner pipe are sealed together by a sealing end plate.

[0012] Furthermore, the inner tube includes an upper inner tube and a lower inner tube, the top of the lower inner tube is sealed to the upper inner tube, and the inner diameter of the lower inner tube is larger than the inner diameter of the upper inner tube.

[0013] Furthermore, the bottom end of the upper inner tube extends into the lower inner tube, and the vent hole is located on the side wall of the lower inner tube above the bottom end of the upper inner tube.

[0014] Furthermore, the top of the lower inner tube is sealed to the upper inner tube via a movable ring plate.

[0015] Furthermore, the expansion mechanism includes a metal corrugated section.

[0016] Furthermore, the exhaust port is connected to a negative pressure duct.

[0017] The beneficial effects of this invention are:

[0018] By removing gas from the high-temperature ash particles through the gas discharge mechanism, the gas content of the ash particles is reduced, and their fluidity is also significantly reduced. This can effectively block the initial cause of ash flow in the drum ash cooler and prevent the drum ash cooler from experiencing ash flow due to instantaneous emptying in the ash drop pipe under abnormal operating conditions of the boiler. This protects surrounding equipment and personnel from damage caused by hot slag. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention in a cold state;

[0020] Figure 2 This is a schematic diagram of the structure of the present invention in a hot state;

[0021] Figure 3 This is a schematic diagram illustrating the use of the present invention.

[0022] In the diagram, 1-metal corrugated joint, 2-upper inner pipe, 3-movable ring plate, 4-lower inner pipe, 5-exhaust pipe, 51-exhaust port, 61-upper end plate, 62-lower end plate, 7-negative pressure air duct, 8-insulation cotton, 9-sealing end plate, 10-exhaust hole, 11-boiler, 12-high temperature ash and slag pipeline, 13-ash and slag valve, 14-metal expansion joint, 15-drum slag cooler, 16-adjusting damper. Detailed Implementation

[0023] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0024] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0025] Example 1:

[0026] like Figures 1 to 3 As shown, a metal expansion joint for preventing slag from flowing out of a drum slag cooler includes an inner tube, an expansion mechanism, and a gas discharge mechanism. The expansion mechanism is sleeved outside the inner tube. The inner tube is provided with one or more vent holes 10. The vent holes 10 are connected to the air inlet of the gas discharge mechanism. The gas discharge mechanism is located between the inner tube and the expansion mechanism and extends out of the expansion mechanism. The part of the gas discharge mechanism extending out of the expansion mechanism is provided with an exhaust port 51.

[0027] The phenomenon of slag free-flowing is mainly due to the superfluidity of high-temperature ash particles. This superfluidity is due to two main reasons: firstly, the extremely fine particle size of the material, and secondly, and more importantly, the high gas content of the ash. The small, high-temperature particles are enveloped by a uniformly sized "high-temperature flue gas film." This film results in extremely low rolling and sliding friction coefficients between the small, high-temperature particles, thus creating superfluidity. However, when the gas content of the material decreases or it is cooled to a certain temperature of approximately 400°C, the material loses its superfluidity.

[0028] By removing gas from the high-temperature ash particles through the gas discharge mechanism, the gas content of the particles is reduced, and their fluidity is also significantly reduced. This can effectively block the initial cause of slag flow in the drum slag cooler and prevent the drum slag cooler from experiencing slag flow due to instantaneous emptying in the slag drop pipe under abnormal operating conditions of the boiler (preventing the problem of slag flow in the drum slag cooler), thus protecting surrounding equipment and personnel from damage caused by hot slag.

[0029] In particular, when the slag cooler becomes clogged, the high-temperature ash slag with high gas content will rapidly separate into gas and solid after its kinetic energy is reduced in the metal expansion joint. A large amount of diffused high-temperature gas and a small amount of self-carried dust can be discharged through the gas discharge mechanism.

[0030] The exhaust mechanism is an exhaust pipe 5, which is sleeved outside the inner pipe. One end of the exhaust pipe 5 is sealed to the part of the inner pipe located inside the expansion mechanism, and the other end of the exhaust pipe 5 is sealed to the part of the inner pipe located outside the expansion mechanism.

[0031] The exhaust port 10 is located on the inner pipe, on the side wall inside the exhaust pipe 5.

[0032] The exhaust pipe 5 and the inner pipe are sealed together by a sealing end plate 9.

[0033] A cylindrical annular cavity is formed between the inner pipe, the exhaust pipe 5, and the sealing end plate 9. Part of this cylindrical annular cavity is inside the expansion mechanism, and part of it extends outside the expansion mechanism. Flue gas enters the cylindrical annular cavity through the exhaust port 10 and is discharged through the exhaust port 51.

[0034] The inner tube includes an upper inner tube 2 and a lower inner tube 4. The top of the lower inner tube 4 is sealed to the upper inner tube 2, and the inner diameter of the lower inner tube 4 is larger than the inner diameter of the upper inner tube 2.

[0035] The inner diameter of the lower inner tube 4 is larger than that of the upper inner tube 2, which can form a larger expansion cavity in the lower inner tube 4 at the bottom of the metal expansion joint. This facilitates the rapid separation of gas and solid after the high-temperature ash with high gas content loses kinetic energy. After the gas-solid separation, the high-temperature gas and a small amount of dust that diffuse out from the upper part of the expansion cavity are discharged from the expansion cavity through the exhaust port 10 and enter the cylindrical annular cavity formed between the lower inner tube 4 and the exhaust pipe 5.

[0036] The bottom end of the upper inner tube 2 extends into the lower inner tube 4, and the vent 10 is located on the side wall of the lower inner tube 4 above the bottom end of the upper inner tube 2. This prevents solid ash and slag from flowing out from the vent 10 during falling.

[0037] The top of the lower inner tube 4 is sealed to the upper inner tube 2 via a movable ring plate 3.

[0038] The movable ring plate 3 can drive the lower inner tube 4 and the upper inner tube 2 to move relative to each other along the inner tube axis when the expansion mechanism is heated (hot state) or cooled (cold state), thereby achieving expansion or contraction. This increases the space inside the inner tube in the hot state, allowing it to hold more ash and slag.

[0039] The exhaust pipe 5 extends from the bottom of the expansion mechanism.

[0040] The bottom of the lower inner tube 4 is sealed to the portion of the exhaust pipe 5 extending from the expansion mechanism. The top of the exhaust pipe 5 is sealed to the lower inner tube 4.

[0041] The expansion mechanism includes a metal bellows 1.

[0042] The top of the expansion mechanism is connected to the upper inner tube 2 via the upper end plate 61, and the bottom of the expansion mechanism is connected to the exhaust pipe 5 via the lower end plate 62.

[0043] The exhaust port 51 is connected to a negative pressure duct 7.

[0044] The negative pressure duct 7 facilitates the rapid discharge of high-temperature flue gas, and the negative pressure air volume can be adjusted to a suitable air volume by adjusting the damper 16.

[0045] Insulation cotton 8 is provided between the inner tube and the expansion mechanism.

[0046] The exhaust port 10 is a round hole with a diameter of 30-40mm.

[0047] The exhaust port 51 has one or more (e.g., two) round holes with a diameter of 120-150 mm.

[0048] The hot slag with high gas content, flowing from the slag discharge pipe of boiler 11, enters the metal expansion joint 14 via the high-temperature ash slag pipeline 12 and ash slag valve 13. Through expansion of the expansion chamber and negative pressure suction of the negative pressure air duct 7, the gas content of the hot slag is further reduced to a significant extent before entering the drum slag cooler 15. The metal expansion joint is simple to manufacture and has increased functionality. Within the original limited space, it effectively solves the problem of slag overflow and gravity flow in the drum slag cooler through expansion and negative pressure suction. It can be used in new boilers and can also be widely used in the renovation of existing boilers.

[0049] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A metal expansion joint for preventing slag from flowing out of a drum slag cooler, characterized in that: The device includes an inner tube, an expansion mechanism, and a gas discharge mechanism. The expansion mechanism is sleeved outside the inner tube. The inner tube has one or more exhaust holes, which are connected to the inlet of the gas discharge mechanism. The gas discharge mechanism is located between the inner tube and the expansion mechanism and extends out of the expansion mechanism. The portion of the gas discharge mechanism extending out of the expansion mechanism has an exhaust port. The inner tube includes an upper inner tube and a lower inner tube. The top of the lower inner tube is sealed to the upper inner tube, and the inner diameter of the lower inner tube is larger than that of the upper inner tube. The bottom end of the upper inner tube extends into the lower inner tube. The exhaust hole is located on the side wall of the lower inner tube above the bottom end of the upper inner tube. The top of the lower inner tube is sealed to the upper inner tube through a movable ring plate. The bottom of the lower inner tube is sealed to the portion of the exhaust pipe extending out of the expansion mechanism. The top of the exhaust pipe is sealed to the lower inner tube. The gas discharge mechanism is an exhaust pipe, which is sleeved outside the inner pipe. One end of the exhaust pipe is sealed to the portion of the inner pipe located inside the expansion mechanism, and the other end of the exhaust pipe is sealed to the portion of the inner pipe located outside the expansion mechanism. The exhaust port is located on the side wall of the inner pipe inside the exhaust pipe. The expansion mechanism includes a metal bellows. The exhaust port is connected to a negative pressure duct.

2. The metal expansion joint for preventing slag flow in a drum slag cooler according to claim 1, characterized in that: The exhaust pipe extends from the bottom of the expansion mechanism.

3. A metal expansion joint for preventing slag flow in a drum slag cooler according to claim 1, characterized in that: The exhaust pipe and the inner pipe are sealed together by a sealing end plate.

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