Coal mill coal powder initial temperature raising device

Abstract

The utility model provides a kind of coal pulverizer coal dust initial temperature promotion device, it is related to the technical field of coal-fired unit, including the flue between denitration device and air preheater and the flue gas inlet of coal pulverizer are communicated to the first pipeline leading out between them, high-temperature dust collector and temperature rising fan are sequentially provided on the first pipeline along the flow direction of flue gas;Flue between induced draft fan and chimney and the flue of first pipeline and second pipeline between high-temperature dust collector and temperature rising fan are converged;Valve group is arranged on the first pipeline and second pipeline;Valve group electric signal is connected with temperature control unit, for calculating the drying output demand temperature of coal pulverizer, solve the existing preprocessing easy to return moisture and technical problem of backflow abrasion equipment, reach the technical effect that internal flue gas of system is used to provide heat for coal pulverizer, while saving energy, reducing coal pulverizer explosiveness, improve low load condition boiler combustion state, improve boiler efficiency.

Description

Technical Field

[0001] This utility model relates to the field of coal-fired power unit technology, and in particular to a coal mill pulverized coal initial temperature raising device. Background Technology

[0002] Under flexible peak-shaving conditions in coal-fired power units, when the unit is operating at low load, the temperature of the primary hot air is relatively low, resulting in insufficient drying output of the coal mill. Consequently, the initial temperature of the pulverized coal fed into the boiler is insufficient, causing delayed pulverized coal ignition. This not only reduces the stability of boiler combustion under low load but also affects the safe and stable operation and peak-shaving capacity of the unit. Therefore, it is necessary to improve the drying output of the coal mill, i.e., the temperature of the air-coal mixture, through various means to ensure normal combustion in the boiler.

[0003] Existing methods for increasing the drying output of coal mills include: first, arranging steam heaters on the hot primary air duct to heat the air-coal mixture through an external heat source; second, drying the raw coal by using pretreatment equipment to reduce its moisture content; and third, using a hot air recirculation system to bring the hot air from the coal mill outlet back to the coal mill inlet through pipelines to mix with fresh hot air to increase the temperature.

[0004] However, the existing technology has the following technical problems:

[0005] 1) Steam heaters require an additional connection to the steam pipeline system, and raw coal drying also requires a dedicated drying equipment, which increases the energy consumption of the equipment; moreover, raw coal pretreatment is prone to moisture absorption during storage, which also increases the possibility of explosion.

[0006] 2) The hot air returning from the coal mill carries a large amount of coal powder, which will cause serious wear and tear on the pipelines and equipment, and the coal powder return is also uneconomical. Utility Model Content

[0007] The purpose of this utility model is to provide a coal mill pulverized coal initial temperature raising device to alleviate the technical problems of pretreatment equipment that is prone to moisture return and backflow wear in the prior art.

[0008] This utility model provides a coal mill pulverized coal initial temperature lifting device, comprising: a coal mill, a boiler, a denitrification device, an air preheater, a dust collector, an induced draft fan, and a chimney connected in sequence; a first pipeline leads out of the flue between the denitrification device and the air preheater and connects to the flue gas inlet of the coal mill; a high-temperature dust collector and a heating fan are sequentially arranged on the first pipeline along the flue gas flow direction; a second pipeline leads out of the flue between the induced draft fan and the chimney and merges with the first pipeline in the flue between the high-temperature dust collector and the heating fan;

[0009] Valve groups are installed on the first and second pipelines; the valve groups are electrically connected to a temperature control unit to calculate the required drying output temperature of the coal mill.

[0010] Furthermore, the valve assembly includes a first regulating valve, a second regulating valve, and a main valve;

[0011] The first regulating valve is located at the inlet of the first pipeline near the high-temperature dust collector, the second regulating valve is located on the second pipeline, and the main valve is located at the confluence of the first and second pipelines.

[0012] Furthermore, the first regulating valve includes a stainless steel base material, and a high-chromium cast iron liner is provided on the outside of the stainless steel base material. The outer wall of the high-chromium cast iron liner is coated with a nickel-based alloy.

[0013] Furthermore, the second regulating valve includes a glass flake liner, the exterior of which is coated with a vinyl ester resin coating.

[0014] Furthermore, the operating temperature of the high-temperature dust collector is 300℃~420℃.

[0015] Furthermore, the heating fan is a centrifugal blower.

[0016] Furthermore, a Y-type mixing joint is installed at the junction of the first and second pipelines to guide the flue gas to mix before entering the coal mill.

[0017] Furthermore, the temperature control unit has a built-in PID controller. The input of the PID controller is connected to the temperature sensor and load sensor of the coal mill, and the signal output of the PID controller is connected to the electric actuators of the first regulating valve, the second regulating valve, and the main valve, respectively.

[0018] Beneficial effects:

[0019] This utility model provides a coal mill pulverized coal initial temperature raising device, comprising: a first pipeline leading out of the flue between the denitrification device and the air preheater and connected to the flue gas inlet of the coal mill; a high-temperature dust collector and a heating fan are sequentially arranged on the first pipeline along the flow direction of the flue gas; a second pipeline leading out of the flue between the induced draft fan and the chimney merges with the first pipeline in the flue between the high-temperature dust collector and the heating fan; valve groups are arranged on the first and second pipelines; the valve groups are electrically connected to a temperature control unit for calculating the drying output temperature required by the coal mill.

[0020] By using high-temperature and low-temperature flue gas within the system to provide heat to the coal mill, external heat sources such as steam are eliminated, reducing energy consumption and achieving energy savings. The flue gas is predominantly inert with low oxygen content, reducing the explosiveness within the coal mill and improving the unit's safe operation. The heated flue gas re-enters the furnace, reducing excess oxygen in the furnace under low load conditions and improving boiler efficiency. Simultaneously, it lowers the furnace center temperature, reducing the initial formation of nitrogen oxides. Under the same conditions of downstream equipment and nitrogen oxide emission requirements, this reduces ammonia consumption in the denitrification system, saving resources.

[0021] The high-temperature dust collector installed on the first pipeline has a lower resistivity at around 400℃, making it easier to remove dust, thus improving dust removal efficiency. This results in lower dust content in the flue gas after passing through the high-temperature dust collector, less wear on the equipment, and extended equipment lifespan. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 A schematic diagram of the structure of the coal mill pulverized coal initial temperature lifting device provided in this embodiment of the utility model.

[0024] Icons: 1 - Coal mill; 2 - Boiler; 3 - Denitrification device; 4 - Air preheater; 5 - Dust collector; 6 - Exhaust fan; 7 - Chimney; 8 - High-temperature dust collector; 9 - Heating fan; 10 - Valve group; 101 - First regulating valve; 102 - Second regulating valve; 103 - Main valve; 11 - Temperature control unit. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0027] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0028] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0030] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] The following detailed description, in conjunction with the accompanying drawings, outlines some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0032] The coal mill pulverized coal initial temperature raising device provided by this utility model includes: a coal mill 1, a boiler 2, a denitrification device 3, an air preheater 4, a dust collector 5, an induced draft fan 6, and a chimney 7 connected in sequence. The flue between the denitrification device 3 and the air preheater 4 leads out a first pipeline to the flue gas inlet of the coal mill 1. A high-temperature dust collector 8 and a heating fan 9 are arranged in sequence along the flow direction of the flue gas on the first pipeline. The flue between the induced draft fan 6 and the chimney 7 leads out a second pipeline, which merges with the first pipeline in the flue between the high-temperature dust collector 8 and the heating fan 9.

[0033] A valve group 10 is installed on the first and second pipelines; the valve group 10 is electrically connected to a temperature control unit 11, which is used to calculate the required drying output temperature of the coal mill 1.

[0034] Specifically, such as Figure 1As shown, the coal mill 1, boiler 2, denitrification device 3, air preheater 4, dust collector 5, induced draft fan 6, and chimney 7 are connected in sequence to form the main path for flue gas flow. The coal mill 1 outlet injects the air-coal mixture into the boiler 2 for combustion. The high-temperature flue gas generated by the boiler 2 is discharged from the chimney 7 after passing through the denitrification device 3, air preheater 4 (flue gas temperature drops from about 400℃ to 160℃~110℃), dust collector 5 for dust removal, and induced draft fan 6 for pressurization. A first pipeline is led out from the flue between the denitrification device 3 and the air preheater 4. One end of the first pipeline is connected to the flue, and the other end is connected to the flue gas inlet of the coal mill 1, forming a branch loop on the main path. On the first pipeline, along the flue gas flow direction, a high-temperature dust collector 8 and a heating fan 9 are installed in sequence. That is, the high-temperature dust collector 8 is located on the side closer to the flue between the denitrification device 3 and the air preheater 4, and the heating fan 9 is located on the side closer to the flue gas inlet of the coal mill 1. Simultaneously, a second pipeline is drawn from the flue between the induced draft fan 6 and the chimney 7. One end of the second pipeline is connected to the flue between the induced draft fan 6 and the chimney 7, and the other end merges with the first pipeline in the flue between the high-temperature dust collector 8 and the heating fan 9. In addition, valve groups 10 are installed on both the first and second pipelines. The valve groups 10 are connected to the temperature control unit 11 via electrical signals. The temperature control unit 11 calculates the temperature based on the drying output requirements of the coal mill 1 and controls the opening degree or on / off state of the valve groups 10 via electrical signals.

[0035] It should be noted that all pipe connections are fixed using flanges or welding to ensure airtightness; the high-temperature dust collector 8 and the heating fan 9 are fixed with pipe supports and kept coaxial with the center line of the pipes to reduce the resistance to flue gas flow. The temperature control unit 11 is installed in the control cabinet and communicates with the valve group 10 via shielded cables.

[0036] Through the linkage between the temperature control unit 11 and the valve group 10, the flow rates of the first pipeline (high temperature flue gas) and the second pipeline (low temperature flue gas) are dynamically adjusted according to the drying requirements of the coal mill 1. When the demand is low, only the low temperature clean flue gas from the outlet of the induced draft fan 6 is introduced. When the demand is high, the high temperature (after dust removal by the high temperature dust collector 8) and the low temperature flue gas are mixed to increase the temperature of the air-coal mixture, avoid the high energy consumption problem of existing steam heating, and broaden the operating load range of the unit.

[0037] The high-temperature dust collector 8 is installed in the first pipeline. It takes advantage of the low resistivity of dust in the high-temperature flue gas at about 400℃ to significantly improve dust removal efficiency, reduce dust content in flue gas, reduce dust wear on coal mill 1 and heating fan 9, and extend equipment life.

[0038] This utility model adopts internal flue gas circulation heating, which eliminates the need for an external heat source and utilizes the waste heat of the flue gas to achieve energy saving. Furthermore, the flue gas has a high content of inert gases and a low oxygen content, which can reduce the risk of coal powder explosion inside the coal mill 1.

[0039] In an embodiment of this utility model, the valve assembly 10 includes a first regulating valve 101, a second regulating valve 102, and a main valve 103;

[0040] The first regulating valve 101 is located at the inlet of the first pipeline near the high-temperature dust collector 8, the second regulating valve 102 is located on the second pipeline, and the main valve 103 is located at the junction of the first pipeline and the second pipeline.

[0041] The first regulating valve 101 includes a stainless steel base material, and a high-chromium cast iron liner is provided on the outside of the stainless steel base material. The outer wall of the high-chromium cast iron liner is coated with a nickel-based alloy.

[0042] The second regulating valve 102 includes a glass flake liner, the outside of which is coated with a vinyl ester resin coating.

[0043] The temperature control unit 11 has a built-in PID controller. The input of the PID controller is connected to the temperature sensor and load sensor of the coal mill 1. The signal output of the PID controller is connected to the electric actuators of the first regulating valve 101, the second regulating valve 102 and the main valve 103 respectively.

[0044] Specifically, the first regulating valve 101 is installed at the inlet of the first pipeline near the high-temperature dust collector 8 to control the flow rate of high-temperature, high-dust flue gas drawn from between the denitrification device 3 and the air preheater 4; the second regulating valve 102 is arranged on the second pipeline to regulate the flow rate of low-temperature, clean flue gas drawn from between the induced draft fan 6 and the chimney 7; and the main valve 103 is located at the confluence of the first and second pipelines to control the total flow rate of the mixed flue gas.

[0045] The first regulating valve 101 is constructed with a high-temperature resistant material to cope with high-temperature and high-dust environments; the second regulating valve 102 is constructed with a material for low-temperature, clean flue gas environments containing corrosive components.

[0046] The temperature control unit 11 has a built-in PID controller. The input end of the controller is connected to the temperature sensor and load sensor of the coal mill 1 by cable or wireless signal to collect the temperature and load data of the coal mill 1 in real time. The signal output end is connected to the electric actuator of the first regulating valve 101, the second regulating valve 102 and the main valve 103 respectively. The controller calculates and outputs control signals based on the collected data to dynamically adjust the opening degree of each valve.

[0047] In the embodiments of this utility model, the operating temperature of the high-temperature dust collector 8 is 300℃~420℃.

[0048] The heating fan 9 is a centrifugal blower.

[0049] A Y-type mixing joint is installed at the junction of the first and second pipelines to guide the flue gas to mix before entering the coal mill 1.

[0050] Specifically, the high-temperature dust collector 8 operates in the range of 300℃ to 420℃. The high-temperature, high-dust flue gas is drawn out from the outlet of the denitrification device 3 and first enters the high-temperature dust collector 8. After dust removal, it flows to the heating fan 9. The heating fan 9 is a centrifugal blower, installed on the first pipeline after the high-temperature dust collector 8, which is used to provide power to transport the dust-removed high-temperature flue gas to the confluence point. A Y-type mixing joint is provided at the confluence point of the first pipeline and the second pipeline. The low-temperature clean flue gas from the second pipeline enters the first pipeline through this joint. After the two flue gases are mixed, they are pressurized by the heating fan 9 and transported to the coal mill 1.

[0051] The high-temperature dust collector 8 operates in a high-temperature environment of 300℃~420℃. It utilizes the characteristics of low resistivity and good charge performance of dust in this temperature range to improve dust removal efficiency. Compared with conventional low-temperature dust collectors (such as dust collector 5 in the main process, which operates at a temperature of about 120℃), it removes dust from high-temperature flue gas more efficiently and reduces the dust content of the flue gas. The heating fan 9 adopts a centrifugal blower, which has the characteristics of high air pressure, stable flow, and adaptability to high-temperature media. It can provide sufficient power under low-load conditions to ensure the stable delivery of the mixed airflow of high-temperature flue gas and low-temperature flue gas to the coal mill 1.

[0052] The Y-type mixing joint enables the high-temperature flue gas from the first pipeline and the low-temperature flue gas from the second pipeline to form a symmetrically split and uniformly mixed flow field when they converge, reducing eddies and resistance losses and ensuring the temperature uniformity of the mixed flue gas.

[0053] Based on the above embodiments, the specific working process of the coal mill pulverized coal initial temperature lifting device provided by this utility model is as follows:

[0054] During normal operation, the air-coal mixture from the outlet of the coal mill 1 is injected into the boiler 2 for combustion, and the resulting high-temperature flue gas is discharged sequentially. When the drying output of the coal mill 1 is insufficient, the heating fan 9 provides power to draw flue gas that has been dusted by the high-temperature dust collector 8 from between the denitrification device 3 and the air preheater 4, and draw low-temperature clean flue gas from between the induced draft fan 6 and the chimney 7. The two flue gases are mixed and then enter the coal mill 1 to raise the initial temperature of the pulverized coal.

[0055] The temperature control unit 11 receives the temperature and load signals of the coal mill 1 through the PID controller, and automatically adjusts the opening of the first regulating valve 101, the second regulating valve 102 and the main valve 103 to control the mixing ratio and meet the drying temperature requirements under different working conditions.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A device for raising the initial temperature of pulverized coal in a coal mill, comprising: A coal mill (1), boiler (2), denitrification device (3), air preheater (4), dust collector (5), induced draft fan (6), and chimney (7) connected in sequence, characterized in that, The first pipeline leading out of the flue between the denitrification device (3) and the air preheater (4) is connected to the flue gas inlet of the coal mill (1). A high-temperature dust collector (8) and a heating fan (9) are sequentially arranged on the first pipeline along the flow direction of the flue gas. The second pipeline leading out of the flue between the induced draft fan (6) and the chimney (7) merges with the first pipeline in the flue between the high-temperature dust collector (8) and the heating fan (9). A valve group (10) is provided on the first pipeline and the second pipeline; the valve group (10) is electrically connected to a temperature control unit (11) for calculating the drying output temperature required by the coal mill (1).

2. The coal mill pulverized coal initial temperature lifting device according to claim 1, characterized in that, The valve assembly (10) includes a first regulating valve (101), a second regulating valve (102), and a main valve (103); The first regulating valve (101) is located at the inlet of the first pipeline near the high-temperature dust collector (8), the second regulating valve (102) is located on the second pipeline, and the main valve (103) is located at the junction of the first pipeline and the second pipeline.

3. The coal mill pulverized coal initial temperature lifting device according to claim 2, characterized in that, The first regulating valve (101) includes a stainless steel base material, and a high-chromium cast iron liner is provided on the outside of the stainless steel base material. The outer wall of the high-chromium cast iron liner is coated with a nickel-based alloy.

4. The coal mill pulverized coal initial temperature lifting device according to claim 2, characterized in that, The second regulating valve (102) includes a glass flake liner, the exterior of which is coated with a vinyl ester resin coating.

5. The coal mill pulverized coal initial temperature lifting device according to claim 1, characterized in that, The operating temperature of the high-temperature dust collector (8) is 300℃~420℃.

6. The coal mill pulverized coal initial temperature lifting device according to claim 1, characterized in that, The heating fan (9) is a centrifugal blower.

7. The coal mill pulverized coal initial temperature lifting device according to claim 1, characterized in that, A Y-type mixing joint is provided at the junction of the first pipeline and the second pipeline to guide the flue gas to mix before entering the coal mill (1).

8. The coal mill pulverized coal initial temperature lifting device according to claim 2, characterized in that, The temperature control unit (11) has a built-in PID controller. The input end of the PID controller is connected to the temperature sensor and load sensor of the coal mill (1). The signal output end of the PID controller is connected to the electric actuators of the first regulating valve (101), the second regulating valve (102) and the main valve (103).

Images