Modification method of pebble coal disposal system of medium-speed coal mill and pebble coal disposal system

Abstract

The invention discloses a modification method of a pebble coal treatment system of a medium-speed coal mill and the pebble coal treatment system.The modification method comprises the steps that a pebble coal ball mill grinding system is installed on the side face of an electric dust remover, and meanwhile the pebble coal ball mill grinding system and a pebble coal negative pressure collecting system share one pebble coal raw material bin; pebble coal output by the pebble coal ball mill grinding system enters the positive-pressure pulverizing system, pebble coal powder output by the positive-pressure pulverizing system is conveyed out through the pebble coal powder dense-phase pneumatic conveying system, and the pebble coal treatment system transformed through the method can achieve pebble coal treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of power generation in coal-fired power plants, and relates to a method for transforming a pebble coal handling system of a medium-speed coal mill and a pebble coal handling system. Background Art

[0002] The pulverizing system of a coal-fired power plant provides qualified pulverized coal for the economic and stable operation of the boiler. For the medium-speed coal mill pulverizing system, a certain amount of pebble coal will be produced during normal operation. As a solid waste pollutant, the pebble coal produced by some coal-fired units is disposed of in open-air piles. As the boiler operation time increases, the amount of pebble coal gradually increases. The existing pile-up site is very effective, and there is no better disposal measure. At that time, there will be a problem of nowhere to pile up the pebble coal.

[0003] Based on the above research background, a feasibility study on the pebble coal recycling technology was conducted in order to seek a scientific and reasonable technical solution to solve the current pebble coal problem. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method for modifying a pebble coal handling system of a medium-speed coal mill and a pebble coal handling system. The pebble coal handling system modified by the method can realize the disposal of pebble coal.

[0005] To achieve the above object, the present invention discloses a method for modifying a pebble coal handling system of a medium-speed coal mill, comprising:

[0006] The pebble coal ball mill grinding system is installed on the side of the electrostatic precipitator, and the pebble coal ball mill grinding system and the pebble coal negative pressure collection system share a pebble coal raw material bin;

[0007] The pebble coal output from the pebble coal ball mill grinding system enters the positive pressing pulverizing system, and the pebble coal powder output from the positive pressing pulverizing system is transported out through the pebble coal powder dense phase pneumatic conveying system.

[0008] The further improvement of the transformation method of the medium speed coal mill pebble coal handling system of the present invention is:

[0009] Furthermore, the pebble coal ball mill grinding system includes a pebble coal raw material bin, a vibrating feeder, a ball mill, a discharge hopper elevator and a pebble coal powder finished product bin, wherein the outlet of the pebble coal raw material bin is connected to the inlet of the ball mill via the vibrating feeder and the discharge hopper elevator, and the outlet of the ball mill is connected to the inlet of the positive pressing pulverizing system via the pebble coal powder finished product bin.

[0010] Furthermore, the stone coal output from the ball mill is sent into the positive pressing pulverizing system by pneumatic conveying.

[0011] Furthermore, the pebble coal powder dense phase pneumatic conveying system is arranged vertically.

[0012] Furthermore, a PLC control cabinet is configured, wherein the PLC control cabinet is connected to the pebble coal ball mill grinding system, the pebble coal negative pressure collection system, the positive pressure pulverizing system and the pebble coal powder dense phase pneumatic conveying system.

[0013] Furthermore, the PLC control cabinet is configured with an on-site power distribution box for providing electrical energy.

[0014] The invention discloses a medium-speed coal mill pebble coal handling system, which is transformed by a transformation method of the medium-speed coal mill pebble coal handling system, wherein the transformation method of the medium-speed coal mill pebble coal handling system comprises installing a pebble coal ball mill grinding system on the side of an electrostatic precipitator, and simultaneously the pebble coal ball mill grinding system and a pebble coal negative pressure collection system share a pebble coal raw material bin;

[0015] The pebble coal output from the pebble coal ball mill grinding system enters the positive pressing pulverizing system, and the pebble coal powder output from the positive pressing pulverizing system is transported out through the pebble coal powder dense phase pneumatic conveying system.

[0016] The further improvement of the medium speed coal mill pebble coal handling system of the present invention is:

[0017] Furthermore, the pebble coal ball mill grinding system includes a pebble coal raw material bin, a vibrating feeder, a ball mill, a pebble coal negative pressure conveying pneumatic pipeline, a discharge hopper elevator and a pebble coal powder finished product bin, wherein the outlet of the pebble coal raw material bin is connected to the inlet of the ball mill via the vibrating feeder and the discharge hopper elevator, and the outlet of the ball mill is connected to the inlet of the positive pressure pulverizing system.

[0018] Furthermore, the pebble coal powder dense phase pneumatic conveying system is arranged vertically.

[0019] Furthermore, it also includes a PLC control cabinet, wherein the PLC control cabinet is connected to the pebble coal ball mill grinding system, the pebble coal negative pressure collection system, the positive pressure pulverizing system and the pebble coal powder dense phase pneumatic conveying system.

[0020] The present invention has the following beneficial effects:

[0021] In the specific operation of the transformation method of the medium-speed coal mill pebble coal disposal system and the pebble coal disposal system described in the present invention, the pebble coal of the coal-fired thermal power unit belongs to solid hazardous waste according to the policy. Therefore, its treatment must be carried out strictly in accordance with the national policy, which undoubtedly increases the difficulty of treatment. The present invention reuses the pebble coal, and the pebble coal after use is calcined in the boiler to form fly ash and slag. At present, the fly ash and slag of the power plant can be sold as raw materials, thereby turning the unprocessed solid hazardous waste into raw materials for producing finished products, which has very good social and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 This is the structural diagram of the pebble coal negative pressure pneumatic conveying system. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0026] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0027] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0028] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0029] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0032] As is known, the grinding system of the stone coal ball mill is a complex and efficient mechanical system, which is mainly used to grind materials such as stone coal into the required particle size. The following is a detailed analysis of the grinding system of the stone coal ball mill: The grinding system of the stone coal ball mill is mainly composed of the following parts: Feeding part: mainly responsible for feeding the stone coal material to be ground into the grinding part. Usually includes components such as feed hopper and feed screw to ensure that the material can enter the grinding area smoothly and evenly. Grinding part: It is the core of the ball mill. Its main function is to grind the material into the required particle size through the collision and friction between the steel ball and the material. It is mainly composed of cylinder, steel ball, liner, etc. The cylinder is the main bearing component of the ball mill. The steel ball collides and rubs with the material in the cylinder, and the liner plays a role in protecting the cylinder. Discharging part: responsible for discharging the ground material from the ball mill. Usually includes components such as discharge port and discharge screw. The design of the discharge port should ensure that the material can be discharged smoothly, and the discharge screw can transport the material from the inside of the cylinder to the discharge port. Transmission system: It is the power source of the ball mill, responsible for driving the cylinder to rotate, so that the steel balls and materials collide and rub against each other in the cylinder. It usually includes components such as motors, reducers, couplings, etc. to ensure that the ball mill can operate stably and reliably. Lubrication system: It is an important auxiliary part of the ball mill, responsible for providing necessary lubrication and cooling for the transmission system. The main components include oil pumps, oil tanks, oil pipes, etc., to ensure that the transmission system can operate under good lubrication conditions and extend the service life of the equipment.

[0033] The pebble coal negative pressure pneumatic conveying system is an efficient and environmentally friendly material conveying method, especially suitable for conveying powdered or granular materials such as pebble coal. The following is a detailed analysis of the pebble coal negative pressure pneumatic conveying system: The pebble coal negative pressure pneumatic conveying system is mainly composed of the following parts: Pebble coal hopper: used to store and temporarily store the pebble coal materials to be transported. Hopper feeding valve: installed at the connection between the pebble coal hopper and the conveying pipeline, used to control the feed amount of the material to prevent excessive materials from entering the conveying pipeline and causing blockage. Negative pressure dust suction device: The fan generates negative pressure to suck the pebble coal material into the conveying pipeline. Conveying pipeline: used to transport the pebble coal material from the hopper to the target location. Cyclone / bag separator: used to separate the pebble coal material from the air in the conveying pipeline to ensure that the material can be accurately delivered to the target location while avoiding air pollution. Power integration box: as the power source for the operation of the system, it establishes a negative pressure environment and sufficient air volume through the action of the vacuum pump. Control system: Programmatic control of the entire system, including material feeding, conveying, separation and other processes, to ensure that the system can operate stably and reliably.

[0034] Embodiment 1

[0035] The method for transforming the medium-speed coal mill pebble coal handling system of the present invention comprises the following steps:

[0036] The pebble coal negative pressure pneumatic conveying system is used to discharge the pebble coal generated during the operation of the medium-speed coal mill. The pebble coal negative pressure pneumatic conveying system is powered by a Roots blower, the output of the blower measuring point is adjusted by a frequency conversion control system, the cooling system ensures the normal operation of the blower, the soundproof room and silencer are used to reduce the noise of the blower, and the dust is removed by a bag dust collector.

[0037] like Figure 1 As shown, the pebble coal negative pressure pneumatic conveying system includes a Roots blower, a cooling system, a dust removal system, a pebble coal bunker, a pebble coal hopper, a pneumatic valve, a pneumatic feeder, a conveying pipeline and a control system.

[0038] The material flow is as follows: the pebble coal is discharged through the slag discharge door (a size screening device is set up, and large particles that cannot meet the requirements of pneumatic conveying cannot enter, and are cleaned up manually regularly), falls into the pebble coal hopper, enters the conveying pipeline through the pneumatic feeder, and then enters the pebble coal bin for separation. After separation, the gas enters the dust removal system for dust removal, and then is discharged into the atmosphere through the Roots blower.

[0039] The present invention installs the pebble coal ball mill grinding system on the side of the electrostatic precipitator. This position can share a pebble coal raw material bin with the pebble coal negative pressure collection system. At the same time, this area is close to the electrostatic precipitator, and there is no need to add a dust removal fan. The collection powder bin can be directly introduced into the inlet of the electrostatic precipitator. Since the dust of the newly added system is a small amount of dust leaked from the equipment body, its overall content is very small, and the negative pressure of the boiler electrostatic precipitator system can be directly used for suction. It is estimated that the dust suction power does not exceed 10kW. Compared with the total air volume of the induced draft fan, its proportion is basically negligible, and it has no effect on the original dust removal system.

[0040] The grinding system of the stone coal ball mill includes a stone coal raw material bin, a GZ3 type electromagnetic vibrating feeder, The pebble coal raw material warehouse is directly connected to the pebble coal negative pressure pneumatic conveying system. Considering the need to deal with the accumulated pebble coal, an accumulated pebble coal inlet is added at the interface between the pebble coal raw material warehouse and the vibrating feeder, and a small bucket elevator is used for feeding. The accumulated pebble coal is transported to the feeding port area of ​​the ball mill by the pebble coal bucket.

[0041] The pebble coal output from the ball mill is sent to the positive pressure pulverizing system by pneumatic conveying. Therefore, the positive pressure conveying method is adopted. Considering that the pulverizing system has normal dry airflow, in order not to affect the normal operation of the coal mill, less conveying airflow is used. Therefore, dense phase pneumatic conveying is more suitable. In addition, considering the continuity of system operation, the continuous dense phase conveying of pebble coal powder has the least interference with the original system.

[0042] The pebble coal powder adopts dense phase pneumatic conveying technology and can use a vertical two-stage silo pump to achieve continuous dense phase conveying. The silo pump is arranged at the bottom of the pebble coal powder finished product silo, and is transported back to the pulverizer inlet along the lower channel of the horizontal flue between the air preheater and the electrostatic precipitator, and the pebble coal powder is sent into the coal drop pipe. The pebble coal powder is connected to the two pulverizers on the bottom layer, and two pumps are installed, each pump is equipped with a conveying pipeline.

[0043] The dense phase pneumatic conveying system of gravel and coal powder includes a storage pump, a feeding pump, a feeder and a compressed air intake assembly. The system is arranged vertically. The storage pump is located above the feeding pump. The inlet of the storage pump is controlled by an inlet dome valve with a sealing ring. The feeding pump provides a continuous and stable amount of material for the feeder.

[0044] The feeder is driven by a standard induction motor with a gearbox. The frequency converter controls the feeder's rotation speed and thus the feed rate. The air consumption of a single silo pump is 7.7Nm 3 / min, the air consumption of the whole system is 15.4Nm 3 / min, the system runs continuously. When the flow rate of stone pulverized coal decreases, the continuous conveying mode can be adjusted to the interval conveying mode, or the continuous conveying flow rate can be reduced.

[0045] During the feeding process, the feed pump is pressurized to maintain a given pressure, and the storage pump achieves the function of periodically replenishing materials for the feed pump through alternating pressure balance with the feed pump and the gravel and coal powder silo, so as to achieve a continuous and stable feeding process.

[0046] The moisture and sulfur content of stone coal powder are both low, and low-temperature corrosion is not likely to occur in winter conditions, so there is no need to consider adding a heating system.

[0047] The present invention provides a pebble coal negative pressure pneumatic conveying system, a pebble coal powder dense phase pneumatic conveying system and a pebble coal ball mill grinding system;

[0048] The present invention is equipped with a PLC control cabinet, adopts a Schneider or Siemens small PLC, is equipped with a touch screen, and reserves an Ethernet host computer communication interface. The interface demarcation point with the demander's DCS (or host computer) is at the supplier's PLC communication interface. The PLC control cabinet is connected to a pebble coal negative pressure pneumatic conveying system, a pebble coal powder dense phase pneumatic conveying system and a pebble coal ball mill grinding system.

[0049] A power distribution box is added on site to provide power for the inverter control box, solenoid valve box and instruments. The purchaser provides a 380 / 220VAC power supply to the incoming switch of the local power distribution box.

[0050] The newly added equipment is designed according to the on-site PLC control mode, and the PLC equipment required by each system is necessary for the system to operate independently. In the specific implementation stage of the present invention, the PLC control system of the entire system can be considered as a whole and centrally arranged according to the actual transformation plan, and the cables, control cabinets and other components can be appropriately reduced to save investment and reduce the complexity of the system. At the same time, after the transformation, the newly added equipment can also be introduced into the DCS centralized control, and the DCS centralized control can be realized by only introducing the on-site PLC signal into the upper computer communication interface.

[0051] However, due to the harsh working environment of pebble coal and ball mill equipment, and once the equipment fails, it takes a long time for the operating personnel to reach the site from the control room, which is not conducive to timely handling of the fault. Therefore, on-duty personnel are still required on site. Therefore, local control is given priority to save investment and improve the maintenance reliability of equipment.

[0052] Each device of the present invention needs to be connected to a 380VAC / 220VAC three-phase four-wire total power supply from an electrical system, and a corresponding power cabinet is provided, and the wiring position is selected between two electrostatic precipitators.

[0053] It should be noted that pebble coal is gangue with a certain calorific value. Therefore, its reuse can realize resource recovery and reduce a certain amount of raw coal consumption. Therefore, it has a certain energy-saving and consumption-reducing effect. In the current domestic carbon reduction context, it has positive significance.

[0054] Embodiment 2

[0055] The medium-speed coal mill pebble coal handling system described in this embodiment is transformed by the transformation method of the medium-speed coal mill pebble coal handling system described in the first embodiment.

[0056] In this embodiment, the pebble coal ball mill grinding system includes a pebble coal raw material bin, a vibrating feeder, a ball mill, a pebble coal negative pressure conveying pneumatic pipeline, a discharge hopper elevator and a pebble coal powder finished product bin, wherein the outlet of the pebble coal raw material bin is connected to the inlet of the ball mill via the vibrating feeder and the discharge hopper elevator, and the outlet of the ball mill is connected to the inlet of the positive pressure pulverizing system.

[0057] In this embodiment, the pebble-coal powder dense phase pneumatic conveying system is arranged vertically.

[0058] In this embodiment, a PLC control cabinet is also included, wherein the PLC control cabinet is connected to the pebble coal ball mill grinding system, the pebble coal negative pressure collection system, the positive pressure pulverizing system and the pebble coal powder dense phase pneumatic conveying system.

[0059] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0060] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0061] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for transforming a medium-speed coal mill pebble coal handling system, characterized in that: include: The pebble coal ball mill grinding system is installed on the side of the electrostatic precipitator, and the pebble coal ball mill grinding system and the pebble coal negative pressure collection system share a pebble coal raw material bin; The pebble coal output from the pebble coal ball mill grinding system enters the positive pressing pulverizing system, and the pebble coal powder output from the positive pressing pulverizing system is transported out through the pebble coal powder dense phase pneumatic conveying system.

2. The method for transforming the pebble coal handling system of a medium-speed coal mill according to claim 1, characterized in that: The pebble coal ball mill grinding system includes a pebble coal raw material bin, a vibrating feeder, a ball mill, a discharge hopper elevator and a pebble coal powder finished product bin, wherein the outlet of the pebble coal raw material bin is connected to the inlet of the ball mill via the vibrating feeder and the discharge hopper elevator, and the outlet of the ball mill is connected to the inlet of the positive pressing pulverizing system via the pebble coal powder finished product bin.

3. The method for transforming the pebble coal handling system of a medium-speed coal mill according to claim 2, characterized in that: The stone coal output from the ball mill is sent into the positive pressing pulverizing system by pneumatic conveying.

4. The method for transforming the pebble coal handling system of a medium-speed coal mill according to claim 1, characterized in that: The pebble coal powder dense phase pneumatic conveying system adopts a vertical arrangement.

5. The method for transforming the pebble coal handling system of a medium-speed coal mill according to claim 1, characterized in that: A PLC control cabinet is configured, wherein the PLC control cabinet is connected to the pebble coal ball mill grinding system, the pebble coal negative pressure collection system, the positive pressure pulverizing system and the pebble coal powder dense phase pneumatic conveying system.

6. The method for transforming the pebble coal handling system of a medium-speed coal mill according to claim 1, characterized in that: The PLC control cabinet is configured with an on-site power distribution box for providing electrical energy.

7. A medium speed coal mill stone coal handling system, characterized in that: The medium-speed coal mill pebble coal handling system is transformed by the transformation method described in claim 1.

8. The medium speed coal mill pebble coal handling system according to claim 7, characterized in that: The pebble coal ball mill grinding system includes a pebble coal raw material bin, a vibrating feeder, a ball mill, a discharge hopper elevator and a pebble coal powder finished product bin, wherein the outlet of the pebble coal raw material bin is connected to the inlet of the ball mill via the vibrating feeder and the discharge hopper elevator, and the outlet of the ball mill is connected to the inlet of the positive pressing pulverizing system via the pebble coal powder finished product bin.

9. The medium speed coal mill pebble coal handling system according to claim 7, characterized in that: The pebble coal powder dense phase pneumatic conveying system adopts a vertical arrangement.

10. The medium speed coal mill pebble coal handling system according to claim 7, characterized in that: It also includes a PLC control cabinet, wherein the PLC control cabinet is connected to the pebble coal ball mill grinding system, the pebble coal negative pressure collection system, the positive pressure pulverizing system and the pebble coal powder dense phase pneumatic conveying system.

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