WO2025156512A1 - Dust removal apparatus for slag bin of slag dryer for thermal power plant and dust removal method therefor - Google Patents

Abstract

The present application discloses a dust removal apparatus for a slag bin of a slag dryer for a thermal power plant and a dust removal method therefor. The dust removal apparatus comprises a dust collecting cover mounted on a slag discharge port of a slag bin. The dust collecting cover is connected to a horizontal section of an air-cooled slag dryer by means of a pipe, and negative pressure generated at the horizontal section of the air-cooled slag dryer is used for providing suction required by the dust collecting cover for dust collection. A dust-containing gas collected by the dust collecting cover is used as cooling air of the air-cooled slag dryer, and is delivered to a furnace after cooling slag on a conveyor belt. A pipe adjusting door is mounted on the pipe. During slag unloading from the slag bin, the degree of opening of the pipe adjusting door is adjusted on the basis of the slag unloading volume and the conditions of flying dust to adjust the air volume of the dust collecting cover. According to the present application, dust removal from the slag bin of the slag dryer is completed by using the negative pressure in the furnace without additionally increasing the amount of cold air entering the furnace, therefore saving more energy. In addition, a filter surface in the form of a conventional cloth bag or the like is not needed, and generation of steam in the slag bin and a low environmental temperature have no impact on the dust removal process, so that the working conditions of discharging dry slag and wet slag from the slag bin can both be adapted to, such that the present application has strong adaptability to seasons and regions.

Description

A dust removal device and dust removal method for a slag bin of a dry slag machine in a thermal power plant

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to a Chinese patent application filed with the Patent Office of China on January 22, 2024, with application number 202410088530.X and invention name “A dust removal device for a slag bin of a dry slag machine in a thermal power plant and a dust removal method thereof”, the entire contents of which are incorporated herein by reference.

Technical Field

The present application belongs to the technical field of pollutant treatment in thermal power plants, and specifically relates to a dust removal device for a slag bin of a dry slag machine in a thermal power plant and a dust removal method thereof.

Background Art

In current thermal power generation, slag removal is mostly done using air-cooled dry slag removal. Each boiler is typically equipped with a dry slag removal system consisting of an air-cooled steel belt conveyor, a slag crusher, and two bucket elevators, which convey the slag directly to a slag bin. Two slag discharge ports are located at the bottom of the slag bin, allowing for either dry or wet slag discharge, depending on the application.

During the slag bin unloading process, dust is inevitably generated. As my country's requirements for unorganized emissions become increasingly stringent, thermal power plants have taken measures to control dust during the slag unloading process. The main method is to add negative pressure dust suction at the slag discharge port and send the dust-laden gas to the bag dust collector. The dust is collected by the bag dust collector and then disposed of in a unified manner.

Existing technologies offer excellent dust removal performance during dry slag discharge. However, during wet slag discharge, the high temperature of the slag in the slag bin generates a large amount of water vapor after the dry slag passes through the twin-shaft agitator. This water vapor, along with the dust, is drawn into the bag filter, causing the bags to become clogged, increasing resistance and reducing dust removal efficiency. During winter operation in northern China, the ash hopper can become ice-bound, preventing ash delivery. Therefore, a dust removal technology suitable for wet slag discharge from the slag bin is urgently needed.

Summary of the Invention

The purpose of this application is to address the problems in the above-mentioned prior art and provide a slag bin dust removal device and a dust removal method for a thermal power plant dry slag machine, which utilizes the negative pressure of the furnace to absorb dust and can adapt to the working conditions of discharging dry slag and wet slag from the slag bin at the same time. It has strong adaptability to seasons and regions and has a better dust removal effect.

In order to achieve the above objectives, this application has the following technical solutions:

A dust removal device for a slag bin of a slag dryer in a thermal power plant, comprising a dust collecting hood mounted on a slag discharge port of the slag bin, the dust collecting hood being connected to a horizontal section of an air-cooled slag dryer via a pipeline, and utilizing the negative pressure generated by the horizontal section of the air-cooled slag dryer to provide the dust collecting hood with the suction force required for dust collection;

The dust-laden gas collected by the dust hood is used as cooling air for the air-cooled slag dryer and is sent into the furnace after cooling the slag on the conveyor belt. A pipe regulating valve is installed on the pipe. When unloading slag from the slag bin, the air volume of the dust hood is adjusted by adjusting the opening of the pipe regulating valve according to the unloading amount and dust situation.

As an optional solution, the dust hood is a gradually expanding umbrella-shaped structure, and the end of the dust hood with a smaller diameter is connected to the slag discharge port of the slag bin; the pipe is inserted into the interior of the dust hood from the side of the dust hood and connected to the horizontal section of the air-cooled dry slag machine.

As an optional solution, the dust hood is respectively provided with a first dust hood exhaust port, a second dust hood exhaust port, a slag bin dry exhaust port and a slag bin wet exhaust port on the end face connected to the slag bin discharge port; the first dust hood exhaust port and the second dust hood exhaust port are symmetrically arranged on both sides of the line connecting the slag bin dry exhaust port and the slag bin wet exhaust port.

As an optional solution, an electric telescopic opening is provided at one end of the dust collecting hood with a larger diameter, and the distance between the dust collecting hood outlet and the slag transport vehicle is adjusted by the electric telescopic opening.

As an optional solution, the inner walls of the dust collecting hood and the pipeline are sprayed with ceramic materials that are wear-resistant and corrosion-resistant.

As an optional solution, the air-cooled slag dryer is provided with a head air volume regulating door at the head of the conveyor belt. A thermal logic interlock is provided between the head air volume regulating door and the pipeline regulating door. The thermal logic interlock is used to achieve:

When the duct regulating valve is adjusted to the required air volume of the dust collecting hood, the head air volume regulating valve is adjusted according to the total air volume required by the air-cooled dry slag machine including the air volume required by the dust collecting hood, so that the total air volume required by the air-cooled dry slag machine including the air volume required by the dust collecting hood does not exceed 1% of the total air volume of the boiler combustion.

A method for removing dust from a slag bin of a slag dryer in a thermal power plant comprises the following steps:

A dust collecting hood is installed on the slag discharge port of the slag bin, and the dust collecting hood is connected to the horizontal section of the air-cooled slag dryer through a pipeline. When the slag bin is unloading, the horizontal section of the air-cooled slag dryer is used to provide negative pressure for the dust collecting hood, and the dust collecting hood collects dust under the action of the negative pressure;

Adjust the pipe valve opening and the air volume of the dust collecting hood according to the slag discharge amount and dust emission situation;

The dust-laden gas collected by the dust hood is used as cooling air for the air-cooled slag dryer and is sent into the furnace after cooling the slag on the conveyor belt.

As an optional solution, the head air volume regulating door of the air-cooled slag dryer is linked to the pipe regulating door through thermal logic interlocking. The air volume required by the dust collector is deducted from the total air volume required by the air-cooled slag dryer to obtain the air volume required by the air-cooled slag dryer at the head of the conveyor belt. After PID calculation, it outputs the opening control instruction of the head air volume regulating door to control the opening of the head air volume regulating door so that the air volume required by the air-cooled slag dryer at the head of the conveyor belt is equal to the total air volume required by the air-cooled slag dryer minus the air volume required by the dust collection hood, so that the total air volume required by the air-cooled slag dryer including the air volume required by the dust collection hood does not exceed 1% of the total air volume of the boiler combustion.

Compared with the prior art, this application has at least the following beneficial effects:

By installing a dust hood on the slag discharge port of the slag bin, connecting the dust hood to the horizontal section of the air-cooled dry slag machine through a pipe, and utilizing the negative pressure generated by the horizontal section of the air-cooled dry slag machine, the dust hood is provided with the suction force required for dust collection. At the same time, the dust-laden gas collected by the dust hood is used as cooling air for the air-cooled dry slag machine, and is sent into the furnace after cooling the slag on the conveyor belt. The dust removal device proposed in this application utilizes the negative pressure of the furnace itself to complete the dust removal of the slag bin of the dry slag machine, without the need to increase the amount of cold air entering the furnace, and is therefore more energy-efficient. At the same time, the dust removal device of this application does not require a traditional filter surface such as a bag. The generation of water vapor in the slag bin and the low ambient temperature have no effect on the dust removal process. It can adapt to the working conditions of discharging dry slag and wet slag from the slag bin at the same time, has strong seasonal and regional adaptability, and has a more stable dust removal effect. The structure and dust removal process flow of the dust removal device for the slag bin of the thermal power plant dry slag machine proposed in this application are simple, do not require additional excessive equipment, have low investment costs, and occupy a small area, and have broad application prospects.

Furthermore, the air-cooled slag dryer of the present application is provided with a head air volume adjustment door at the head of the conveyor belt, and a thermal logic interlock is provided between the head air volume adjustment door and the pipeline adjustment door. The head air volume adjustment door of the slag dryer can be interlocked and adjusted according to the air supply volume of the dust hood. Through the interlock adjustment, the total air volume required by the air-cooled slag dryer, including the air volume required by the dust hood, is ensured to be no more than 1% of the total air volume of the boiler combustion, thereby avoiding excessive cold air from entering the furnace and affecting the thermal efficiency of the boiler.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

FIG1 is a schematic structural diagram of a slag bin dust removal device for a thermal power plant dry slag machine according to an embodiment of the present application;

FIG2 is a schematic diagram of a top view of the dust collecting hood according to an embodiment of the present application;

FIG3 is a schematic side view of the dust collecting hood according to an embodiment of the present application;

In the attached figure: 1-slag pit; 2-air-cooled slag dryer; 3-slag bin; 4-dust hood; 5-head air volume adjustment door; 6-pipe adjustment door; 41-first dust hood exhaust outlet; 42-second dust hood exhaust outlet; 43-slag bin dry outlet; 44-slag bin wet outlet.

DETAILED DESCRIPTION

In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

Referring to Figure 1 , this embodiment of the present application provides a dust removal device for a slag bin of a thermal power plant slag dryer. The device comprises a dust hood 4 mounted on the slag discharge port of the slag bin 3. The hood 4 has a gradually expanding, umbrella-like structure, and the smaller end of the hood 4 is connected to the slag discharge port of the slag bin 3. The hood 4 is connected to the horizontal section of the air-cooled slag dryer 2 via a pipe. Furthermore, in this embodiment of the present application, a pipe is inserted from the side of the hood 4 into the interior of the hood 4 and connected to the horizontal section of the air-cooled slag dryer 2. The negative pressure generated by the horizontal section of the air-cooled slag dryer 2 provides the suction force required for dust collection in the hood 4. The dust-laden gas collected by the hood 4 serves as cooling air for the air-cooled slag dryer 2 and is delivered to the furnace after cooling the slag on the conveyor belt. A pipe damper 6 is installed on the pipe. When the slag bin 3 is unloaded, the air volume of the hood 4 is adjusted by adjusting the opening of the pipe damper 6 according to the amount of slag discharged and the level of dust emission. The air-cooled slag dryer 2 of the embodiment of the present application is provided with a head air volume adjustment door 5 at the head of the conveyor belt, and a thermal logic interlock is provided between the head air volume adjustment door 5 and the pipeline adjustment door 6. The thermal logic interlock is used to achieve: when the pipeline adjustment door 6 is adjusted to the required air volume according to the dust collecting hood 4, the head air volume adjustment door 5 is adjusted according to the total air volume required by the air-cooled slag dryer 2 including the air volume required by the dust collecting hood 4, so that the total air volume required by the air-cooled slag dryer 2 including the air volume required by the dust collecting hood 4 does not exceed 1% of the total air volume of the boiler combustion, thereby avoiding excessive cold air entering the furnace and affecting the thermal efficiency of the boiler.

Referring to Figure 2 , in one possible embodiment, the dust hood 4 of the present embodiment is provided with a first dust hood exhaust port 41, a second dust hood exhaust port 42, a slag bin dry outlet 43, and a slag bin wet outlet 44 on the end surface thereof connected to the slag bin 3. Furthermore, the first dust hood exhaust port 41 and the second dust hood exhaust port 42 are symmetrically arranged on either side of a line connecting the slag bin dry outlet 43 and the slag bin wet outlet 44.

In a possible embodiment, the dust collecting hood 4 of the embodiment of the present application is provided with an electric telescopic opening at one end with a larger diameter, as shown in FIG3 , and the distance between the dust collecting hood outlet and the slag transport vehicle is adjusted by the electric telescopic opening to improve the dust collection efficiency.

In a possible embodiment, the dust collecting hood 4 and the inner wall of the pipeline are sprayed with a ceramic material that is wear-resistant and corrosion-resistant to achieve the effect of wear and corrosion resistance.

The dust removal device for the slag bin of the thermal power plant dry slag machine proposed in the embodiment of the present application has a simple structure and does not require additional equipment, thus saving investment and space. The dust removal device of the embodiment of the application does not require additional equipment such as Roots blowers, which is more energy-efficient. Since the dust removal device of the embodiment of the application does not have a filter surface in the form of a bag, the generation of water vapor in the slag bin and the low ambient temperature have no effect on the dust removal process, and it has strong adaptability to seasons and regions. The air volume adjustment valve at the head of the dry slag machine of the dust removal device of the embodiment of the application can be interlocked and adjusted according to the air supply volume of the dust collection hood, without increasing the amount of cold air entering the furnace and without affecting the efficiency of the boiler.

Another embodiment of the present application further provides a method for removing dust from a slag bin of a dry slag machine in a thermal power plant, comprising the following steps:

A dust collecting hood 4 is installed on the slag discharge port of the slag bin 3, and the dust collecting hood 4 is connected to the horizontal section of the air-cooled slag dryer 2 through a pipeline. When the slag bin 3 is unloading slag, the horizontal section of the air-cooled slag dryer 2 is used to provide negative pressure for the dust collecting hood 4, and the dust collecting hood 4 collects dust under the action of the negative pressure;

Adjust the opening of the pipe valve 6 and the air volume of the dust collecting hood 4 according to the slag discharge amount and dust emission situation;

The dust-laden gas collected by the dust collecting hood 4 is used as cooling air for the air-cooled slag dryer 2 and is sent into the furnace after cooling the slag on the conveyor belt.

Furthermore, the embodiment of the present application associates the head air volume regulating door 5 of the air-cooled slag dryer 2 with the pipeline regulating door 6 through a thermal logic interlock. According to the air volume value obtained by subtracting the air volume required by the dust hood 4 from the total air volume required by the air-cooled slag dryer 2, the air volume value required by the air-cooled slag dryer 2 at the head of the conveyor belt is obtained. After PID calculation, the opening control instruction of the head air volume regulating door 5 is output to control the opening of the head air volume regulating door 5 so that the air volume value required by the air-cooled slag dryer 2 at the head of the conveyor belt is equal to the air volume value obtained by subtracting the air volume required by the dust hood 4 from the total air volume required by the air-cooled slag dryer 2, so that the total air volume required by the air-cooled slag dryer 2 including the air volume required by the dust hood 4 does not exceed 1% of the total air volume of the boiler combustion.

The dust removal method for the slag bin of a thermal power plant dry slag machine proposed in this embodiment utilizes negative pressure from the furnace to remove dust. This method can accommodate both dry and wet slag discharge from the slag bin. It features a simple process flow, low investment costs, and a small footprint. Dust removal from the dry slag bin is accomplished by utilizing the furnace's own negative pressure, without increasing the amount of cold air entering the furnace, resulting in greater energy savings. Furthermore, the generation of water vapor in the slag bin and low ambient temperatures have no impact on the dust removal process. The method is highly adaptable to seasonal and regional conditions and has broad application prospects.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them. Although the present application has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present application can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present application should be included in the scope of protection of the claims of the present application.

Claims (8)

A dust removal device for a slag bin of a slag dryer in a thermal power plant, characterized in that it comprises a dust collecting hood (4) installed on a slag discharge port of a slag bin (3), wherein the dust collecting hood (4) is connected to a horizontal section of an air-cooled slag dryer (2) via a pipeline, and utilizes the negative pressure generated by the horizontal section of the air-cooled slag dryer (2) to provide the dust collecting hood (4) with the suction force required for collecting dust; The dust-laden gas collected by the dust collecting hood (4) is used as cooling air for the air-cooled slag dryer (2) and is sent into the furnace after cooling the slag on the conveyor belt; a pipe regulating valve (6) is installed on the pipe, and when the slag bin (3) is unloaded, the opening of the pipe regulating valve (6) is adjusted according to the amount of unloaded slag and the dust emission situation to adjust the air volume of the dust collecting hood (4). The slag bin dust removal device for a thermal power plant slag dryer according to claim 1 is characterized in that the dust collecting hood (4) is a gradually expanding umbrella-shaped structure, and the end with a smaller diameter of the dust collecting hood (4) is connected to the slag discharge port of the slag bin (3); the pipe is inserted into the interior of the dust collecting hood (4) from the side of the dust collecting hood (4) and connected to the horizontal section of the air-cooled slag dryer (2). The slag bin dust removal device for a thermal power plant dry slag machine according to claim 2 is characterized in that the dust collecting hood (4) is respectively provided with a first dust collecting hood exhaust port (41), a second dust collecting hood exhaust port (42), a slag bin dry discharge port (43) and a slag bin wet discharge port (44) on the end surface connected to the slag discharge port of the slag bin (3); the first dust collecting hood exhaust port (41) and the second dust collecting hood exhaust port (42) are symmetrically arranged on both sides of a line connecting the slag bin dry discharge port (43) and the slag bin wet discharge port (44). The slag bin dust removal device for a thermal power plant dry slag machine according to claim 2 is characterized in that an electric telescopic opening is provided at one end of the dust collecting hood (4) with a larger diameter, and the distance between the dust collecting hood outlet and the slag transport vehicle is adjusted by the electric telescopic opening. The slag bin dust removal device for a thermal power plant dry slag machine according to claim 1 is characterized in that the dust collecting hood (4) and the inner wall of the pipeline are sprayed with a ceramic material that is wear-resistant and corrosion-resistant. The dust removal device for the slag bin of the thermal power plant dry slag machine according to claim 1 is characterized in that The air-cooled slag dryer (2) is provided with a head air volume regulating door (5) at the head of the conveyor belt, and a thermal logic interlock is provided between the head air volume regulating door (5) and the pipeline regulating door (6). The thermal logic interlock is used to achieve: When the duct regulating door (6) is adjusted to the required air volume of the dust collecting hood (4), the head air volume regulating door (5) is adjusted according to the total air volume required by the air-cooled slag dryer (2) including the air volume required by the dust collecting hood (4), so that the total air volume required by the air-cooled slag dryer (2) including the air volume required by the dust collecting hood (4) does not exceed 1% of the total air volume of the boiler combustion. A method for removing dust from a slag bin of a slag dryer in a thermal power plant, characterized by being implemented based on the slag bin dust removal device of a thermal power plant slag dryer according to any one of claims 1 to 6, comprising the following steps: A dust collecting hood (4) is installed on the slag discharge port of the slag bin (3), and the dust collecting hood (4) is connected to the horizontal section of the air-cooled slag dryer (2) through a pipeline. When the slag bin (3) is unloading slag, the horizontal section of the air-cooled slag dryer (2) is used to provide negative pressure for the dust collecting hood (4), and the dust collecting hood (4) collects dust under the action of the negative pressure. Adjust the opening of the pipeline regulating valve (6) and the air volume of the dust collecting hood (4) according to the slag discharge amount and dust emission situation; The dust-containing gas collected by the dust collecting hood (4) is used as cooling air for the air-cooled slag dryer (2) and is sent into the furnace after cooling the slag on the conveyor belt. The dust removal method for the slag bin of the thermal power plant slag dryer according to claim 7 is characterized in that the head air volume regulating door (5) of the air-cooled slag dryer (2) is associated with the pipeline regulating door (6) through thermal logic interlocking, and the air volume value obtained by subtracting the air volume required by the dust collecting hood (4) from the total air volume required by the air-cooled slag dryer (2) is obtained. After PID calculation, an opening control instruction of the head air volume regulating door (5) is output to control the opening of the head air volume regulating door (5) so that the air volume value required by the air-cooled slag dryer (2) at the head of the conveyor belt is equal to the air volume value obtained by subtracting the air volume required by the dust collecting hood (4) from the total air volume required by the air-cooled slag dryer (2), so that the total air volume required by the air-cooled slag dryer (2) including the air volume required by the dust collecting hood (4) does not exceed 1% of the total air volume of the boiler combustion.