A ventilation system for coal mills

Abstract

This utility model discloses a coal mill air supply system, belonging to the field of thermal power generation technology. It includes a circulating heating component, an auxiliary heating component, a pipeline flow control component, and several coal mills. The circulating heating component heats cold air supplied to the coal mills via waste heat from the boiler tail flue gas. The auxiliary heating component heats cold air and supplies it to the coal mills during boiler startup or low load. The pipeline flow control component regulates the supply of hot air to one or more coal mills. This utility model effectively solves the problems of existing technologies where plasma heaters and coal mills form a fixed "one-to-one" correspondence, making it difficult to flexibly adapt to heating multiple coal mills, and extending the unit's startup time and reducing its startup efficiency.

Description

Technical Field

[0001] This utility model relates to the field of thermal power generation technology, specifically to a ventilation system for a coal mill. Background Technology

[0002] In the operating system of a thermal power generating unit, the coal mill is a key piece of equipment, and the temperature conditions of its working environment directly affect the drying and grinding efficiency of coal and the stable operation of the unit. To ensure that the coal mill can work normally under different operating conditions (especially during unit startup and low-load operation), it is usually necessary to heat the air entering the coal mill through a heater to provide hot air that meets the process requirements.

[0003] Currently, the commonly used technical solution in the industry is to conventionally arrange plasma air heaters, with one plasma air heater corresponding to one coal mill, specifically for heating the hot air entering that designated coal mill. While this arrangement meets the basic heating needs of the coal mills to a certain extent, it has the following significant problems in practical applications: Limited operational flexibility: Because of the fixed "one-to-one" correspondence between the plasma air heater and the coal mill, only one coal mill can be heated at a time, making it inflexible for heating multiple coal mills; Slow start-up speed: During the start-up phase, multiple coal mills need to be preheated gradually to meet the load increase requirements. However, in the conventional "one-to-one" arrangement, each plasma air heater can only provide heating for one coal mill individually, resulting in the preheating process for multiple coal mills having to be performed sequentially or requiring the deployment of more air heaters, thus prolonging the start-up time and reducing the start-up efficiency of the unit.

[0004] Therefore, given the limitations of existing plasma heater layouts in terms of unit operation flexibility and start-up speed, there is an urgent need for a technical solution that can optimize plasma heater settings to improve the operating performance of thermal power generating units. Utility Model Content

[0005] To address the problems existing in the prior art, this utility model provides an air supply system for a coal mill, aiming to solve the problems of the fixed "one-to-one" correspondence between the plasma heater and the coal mill in the prior art, which makes it unable to flexibly adapt to the heating of multiple coal mills, and prolongs the start-up time of the unit and reduces the start-up efficiency of the unit. To achieve the above objectives, this utility model provides the following technical solution: A coal mill air supply system includes a circulating heating component, an auxiliary heating component, a pipeline flow control component, and several coal mills; the circulating heating component heats cold air supplied to the coal mills via waste heat from flue gas at the boiler tail end; the auxiliary heating component heats cold air and supplies it to the coal mills when the boiler is started or at low load; the pipeline flow control component is used to regulate the supply of hot air to one or more coal mills.

[0006] Furthermore, the circulating heating component is an air preheater; the air preheater uses the waste heat from the flue gas at the tail end of the boiler to heat the cold air.

[0007] Furthermore, the auxiliary heating component is a plasma heater; the plasma heater heats the cold air with heating steam.

[0008] Furthermore, the pipeline flow control component includes a main pipeline and branch pipelines in the same number as the coal mills; several of the coal mills are respectively connected to the main pipeline through the branch pipelines.

[0009] Furthermore, two air preheaters are provided, namely a first air preheater and a second air preheater; the first air preheater and the second air preheater are respectively connected to the main pipeline through pipes.

[0010] Furthermore, an auxiliary pipe is connected in parallel to the main pipe; the auxiliary pipe is located between the first air preheater and the second air preheater; the plasma heater is connected to the auxiliary pipe.

[0011] Furthermore, several branch pipe inlets of the coal mill are equipped with gate valves.

[0012] Furthermore, the pipeline flow control component also includes several electrically operated dampers, which are respectively installed on the auxiliary pipeline and the main pipeline.

[0013] Furthermore, the coal mill is provided in six parts: a first coal mill, a second coal mill, a third coal mill, a fourth coal mill, a fifth coal mill, and a sixth coal mill; two electric dampers are provided on the main pipeline: a first electric damper located between the branch pipelines of the first coal mill and the branch pipelines of the second coal mill, and a second electric damper located between the branch pipelines of the second coal mill and the branch pipelines of the third coal mill; a third electric damper is provided on the auxiliary pipeline.

[0014] Furthermore, one end of the auxiliary pipe is connected to the right side of the first electric damper, and the other end is connected to the left side of the second electric damper.

[0015] The beneficial effects of this utility model are: 1. This utility model, by setting up a main pipeline, branch pipelines, and auxiliary pipelines in conjunction with the gate valve on the coal mill, the first electric damper and the second electric damper on the main pipeline, and the third damper on the auxiliary pipeline, enables one plasma air heater to heat the air entering six coal mills, flexibly distributing hot air to each coal mill to meet the special needs of specific coal mills; by increasing the heating steam of the plasma air heater, any two coal mills can be heated simultaneously. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model; The attached diagram is labeled as follows: 1. Plasma air heater; 2. Main pipe; 3. Branch pipe; 4. First air preheater; 5. Second air preheater; 6. Auxiliary pipe; 7. Sluice gate; 8. First coal mill; 9. Second coal mill; 10. Third coal mill; 11. Fourth coal mill; 12. Fifth coal mill; 13. Sixth coal mill; 14. First electric damper; 15. Second electric damper; 16. Third electric damper; 17. Heating steam. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited to the following embodiments.

[0018] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0019] In the description of this utility model, "first feature" and "second feature" may include one or more of the features.

[0020] In the description of this utility model, "multiple" means two or more.

[0021] In the description of this utility model, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or it may include the first and second features not being in direct contact but being in contact through another feature between them.

[0022] In the description of this utility model, the terms "above", "over" and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicate that the first feature is at a higher horizontal level than the second feature.

[0023] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," and "some examples" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0024] Example See attached Figure 1 This embodiment provides a coal mill air supply system, mainly composed of a circulating heating component, an auxiliary heating component, a pipeline flow control component, and six coal mills. The circulating heating component uses two air preheaters (first air preheater 4 and second air preheater 5), both connected to the main pipeline 2 via pipelines. The first air preheater 4 is located on the right side of the system, and the second air preheater 5 is located on the left side. They are connected in series through the main pipeline 2 to form the main heating path, utilizing the waste heat of the boiler tail flue gas to heat the cold air. The heated hot air is then used as the coal powder conveying medium to supply the coal mill. A plasma air heater 1 is used as an auxiliary heating device, connected in parallel to the main pipeline 2 via an auxiliary pipeline 6. One end of the auxiliary pipeline 6 is connected to the right side of the first electric damper 14 on the main pipeline 2, and the other end is connected to the left side of the second electric damper 15. A third electric damper 16 is provided on the auxiliary pipeline 6 to control its on / off state. The heat source for the plasma air heater 1 is start-up steam, used to supplement heating of the cold air during unit startup or low load. The pipeline flow control component includes a main pipeline 2, auxiliary pipelines 6, and six branch pipelines 3 (corresponding to six coal mills). The main pipeline 2 is equipped with a first electric damper 14 (located between the branch pipeline 3 of the first coal mill 8 and the second coal mill 9) and a second electric damper 15 (located between the branch pipeline 3 of the second coal mill 9 and the third coal mill 10). Each coal mill's branch pipeline 3 inlet is equipped with a gate valve 7 for independently controlling the hot air supply to that single coal mill. The system has a total of six coal mills, namely the first coal mill 8 to the sixth coal mill 13, all connected to the main pipeline 2 via their respective branch pipelines 3.

[0025] In the initial stage of unit startup, the air preheater has no heat source and needs to be assisted by the plasma air heater. In this embodiment, the process of heating the first coal mill 8 or the second coal mill 9 is as follows: after the cold air passes through the second air preheater 5 on the left (at which time there is no heat source), it is heated to the set temperature by the plasma air heater 1 through the auxiliary pipe 6; then it enters the main pipe 2 through the opened third electric damper 16 and flows to the first coal mill 8 or the second coal mill 9. At this time, the inlet gate 7 of other coal mills that are not heated needs to be closed, and the second electric damper 15 needs to be closed, while the first electric damper 14 and the third electric damper 16 need to be opened, to prevent the cold air coming out of the second air preheater 5 from directly entering the first / second coal mill 9 through the main pipe 2.

[0026] In the initial stage of unit startup, the air preheater has no heat source and requires auxiliary heating through a plasma air heater. In this embodiment, the heating process of the third coal mill 10, the fourth coal mill 11, the fifth coal mill 12, or the sixth coal mill 13 is as follows: After passing through the first air preheater 4 on the right, the cold air enters the auxiliary pipe 6 through the open third electric damper 16, is heated by the plasma air heater 1, and then flows to the target coal mill through the main pipe 2. During operation, the gate valve 7 of the coal mill that is not heated is closed, the first electric damper 14 or the second electric damper 15 is closed (to ensure that the cold air coming out of the first air preheater 4 enters the plasma air heater 1 for heating), and the third electric damper 16 is kept open.

[0027] In this embodiment, two coal mills are heated simultaneously: based on the above-mentioned single-mill heating logic, the heating steam 17 supply of the plasma heater 1 is increased, and the inlet gate 7 of the two target coal mills is opened at the same time.

[0028] During the stable operation phase of the unit, the waste heat from the boiler tail flue gas can meet the heating requirements, and the air preheater is working normally. During operation, the third electric damper 16 is closed, the first electric damper 14 and the second electric damper 15 are opened, and the inlet gate valves 7 of all coal mills are opened according to operating requirements. After being heated by the first air preheater 4 and the second air preheater 5, the cold air is delivered to each coal mill through the main pipeline 2 and the branch pipelines 3 to achieve stable heating.

[0029] In this embodiment, the gate 7 is used to isolate non-operating coal mills to avoid hot air waste; the electric damper switches the hot air path through a combination of on / off states to ensure that the heating energy of the plasma heater 1 is accurately distributed to the target coal mill; the steam supply is dynamically adjusted according to the number of heated coal mills to ensure stable hot air temperature. Through the above structural and process design, the system can quickly heat one or more coal mills during the unit startup phase and efficiently utilize waste heat from flue gas during the stable operation phase, significantly improving the unit's startup speed and operational flexibility.

[0030] The above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model. Technologies, shapes, and structural parts not described in detail in this utility model are all known technologies.

Claims

1. A ventilation system for a coal mill, characterized in that: It includes a circulating heating component, an auxiliary heating component, a pipeline flow control component, and several coal mills; the circulating heating component heats cold air supplied to the coal mills by connecting to the waste heat of flue gas at the tail end of the boiler; the auxiliary heating component heats cold air supplied to the coal mills when the boiler is started or at low load; the pipeline flow control component is used to regulate the supply of hot air to one or more coal mills.

2. The air supply system for a coal mill according to claim 1, characterized in that: The circulating heating component is an air preheater; the air preheater uses the waste heat from the flue gas at the tail end of the boiler to heat the cold air.

3. The air supply system for a coal mill according to claim 2, characterized in that: The auxiliary heating component is a plasma heater (1); the plasma heater (1) heats the cold air with heating steam (17).

4. The air supply system for a coal mill according to claim 3, characterized in that: The pipeline flow control assembly includes a main pipeline (2) and branch pipelines (3) in number consistent with the number of coal mills; several of the coal mills are connected to the main pipeline (2) through the branch pipelines (3).

5. A ventilation system for a coal mill according to claim 4, characterized in that: Two air preheaters are provided, namely a first air preheater (4) and a second air preheater (5); the first air preheater (4) and the second air preheater (5) are respectively connected to the main pipeline (2) through pipelines.

6. A ventilation system for a coal mill according to claim 5, characterized in that: An auxiliary pipe (6) is connected in parallel to the main pipe (2); the auxiliary pipe (6) is located between the first air preheater (4) and the second air preheater (5); the plasma heater (1) is connected to the auxiliary pipe (6).

7. A ventilation system for a coal mill according to claim 4, characterized in that: Each of the branch pipes (3) of the coal mill is equipped with a gate valve (7).

8. A ventilation system for a coal mill according to claim 6, characterized in that: The pipeline flow control assembly also includes several electric dampers, which are respectively installed on the auxiliary pipeline (6) and the main pipeline (2).

9. A ventilation system for a coal mill according to claim 8, characterized in that: The coal mills are arranged in six parts, namely the first coal mill (8), the second coal mill (9), the third coal mill (10), the fourth coal mill (11), the fifth coal mill (12), and the sixth coal mill (13); two electric dampers are installed on the main pipeline (2), namely the first electric damper (14) between the branch pipeline (3) of the first coal mill (8) and the branch pipeline (3) of the second coal mill (9), and the second electric damper (15) between the branch pipeline (3) of the second coal mill (9) and the branch pipeline (3) of the third coal mill (10); a third electric damper (16) is installed on the auxiliary pipeline (6).

10. A ventilation system for a coal mill according to claim 9, characterized in that: One end of the auxiliary pipe (6) is connected to the right side of the first electric damper (14), and the other end is connected to the left side of the second electric damper (15).

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