CN2733195Y - Fire coal power plant boiler cold state pulverizing apparatus - Google Patents

Abstract

The utility model provides a cold-state pulverizing device for a coal-fired power station boiler. The device includes a coal mill, an air supply pipe for supplying hot air to the coal mill, and a delivery pipe for sending coal powder in the coal mill into the boiler. The coal pipeline is equipped with a steam heater on the air supply pipeline. Therefore, when the temperature in the boiler is low and the temperature of the air used for coal grinding cannot dry the coal material, or when the boiler is still in a cold state, the steam heater is used to heat it, so that the air used for coal grinding enters through the air supply duct. The coal mill passes through the steam heater before and is heated by the steam heater, so that the temperature of the air entering the coal mill meets the requirements for drying raw coal. Therefore, the coal mill can start working at the initial stage of boiler operation, and the qualified pulverized coal required for grinding can be burned instead of fuel oil as soon as possible, thereby saving the time for pulverized coal grinding and fuel consumption.

Description

Coal-fired power plant boiler cold pulverizing device

technical field

The utility model relates to a pulverizing device, in particular to a device for preparing pulverized coal in a cold state of a coal-fired power station boiler.

Background technique

Existing coal-fired thermal power generation units account for more than 70% of the country's total installed power generation capacity, and each coal-fired unit consists of three parts: a boiler, a steam turbine and a generator. Existing power plant boilers generally use coal-fired methods, and the raw coal needs to be ground into very small powder particles, that is, coal powder, which is blown into the furnace by air for suspension combustion. Therefore, power plant boilers are equipped with corresponding coal-fired pulverizing equipment to produce qualified coal powder with particle size, temperature and dry humidity required for boiler combustion.

Coal mills generally have requirements on the particle size, temperature and dry humidity of the coal fed into the coal mill for grinding. In order to obtain qualified pulverized coal with the required particle size, temperature and dry humidity, in the start-up stage of boiler combustion, generally large-scale thermal power plants first use fuel oil (diesel, heavy oil, etc.) to burn to heat the boiler, and use the thus heated The waste heat of the boiler, through the air supply pipe connecting the boiler and the coal mill, sends the hot air obtained by heating the boiler into the coal mill to grind the qualified coal powder required for boiler combustion through the coal mill, and then The pulverized coal is fed into the combustion chamber of the boiler to burn instead of fuel oil. However, this process consumes a large amount of fuel. The reason is that the coal mill can only be started when the air temperature at the inlet of the coal mill reaches a certain temperature (the temperature is different depending on the type of coal, generally between 150°C and 200°C). The coal is heated and dried in the coal mill, and at the same time, the qualified coal powder that meets the requirements of temperature, particle size and dry humidity is ground, and the qualified coal powder is transported to the boiler through the coal delivery pipeline for combustion, so that through the boiler Internal combustion of pulverized coal instead of fuel combustion.

Especially, in actual situation, because the boiler volume of power plant is very large, it takes a long time to heat the boiler so that the air used for coal grinding is heated to a certain degree. Coal-fired power plant boilers used in thermal power plants, from the ignition of the boiler to the pulverization of the coal mill, the time required varies with the capacity and structure of the unit, as well as the structural type of the boiler and the working mode of the coal mill. Generally, it takes 4-10 hours; in the trial operation stage of the unit and when the unit is overhauled, the time required is longer, often up to 20-70 hours. During this period, the boiler only operates by burning oil, which consumes a lot of energy. fuel volume.

Therefore, there is an urgent need for a milling device and milling method that saves energy, saves time, and reduces costs.

Utility model content

The purpose of the utility model is to provide a cold-state pulverizing device for a coal-fired power station boiler capable of saving energy, shortening boiler start-up and coal grinding time, and reducing costs.

In order to achieve the purpose of this utility model, a cold-state pulverizing device for a coal-fired power plant boiler is provided, which includes a coal mill, an air supply pipe for supplying hot air to the coal mill, and the coal in the coal mill The powder is fed into the coal delivery pipeline of the boiler, and a steam heater is installed on the air supply pipeline.

When the temperature in the boiler is low and the temperature of the air used for coal grinding cannot dry the coal material, such as raw coal, or when the boiler is still in a cold state, use a steam heater to heat, so that the air used for coal grinding is passed through the air supply Before the pipe enters the coal mill, it passes through the steam heater and is heated by the steam heater, so that the temperature of the air entering the coal mill meets the requirements for drying raw coal. Therefore, the coal mill can start working at the initial stage of boiler operation, and the qualified pulverized coal required for grinding can be burned instead of fuel oil as soon as possible, thereby saving the time for pulverized coal grinding and fuel consumption.

The above-mentioned cold-state pulverizing device for a coal-fired power plant boiler, wherein the end of the air supply pipe away from the coal mill is connected to the boiler. A loop is therefore formed between the boiler and the coal mill, optionally the boiler supplies air for drying the coal to the coal mill, and the coal mill supplies the boiler with coal for combustion. For example, when the boiler is not cold, the boiler supplies air for drying coal to the coal mill.

The coal-fired power plant boiler cold-state pulverizing device as described above, wherein the steam heater includes a heating part and connecting parts located on both sides of the heating part for connecting with the air supply pipeline, and the connecting parts are respectively A connecting port communicating with the air supply duct is opened at the end far away from the heating part.

Therefore, the steam heater is convenient to be installed and connected with the air supply pipeline, and the steam heater can be made into a standard unit component which is convenient for installing and removing the air supply pipeline.

The above-mentioned coal-fired power plant boiler cold state pulverizing device, wherein the heating part of the steam heater has at least one set of heating elements, and each set of heating elements includes at least several rows of heating tubes, and the heating The tube has openings for leading in and out the steam so that the steam heats the heating tube when it flows through it.

Generally, the power plant has its own steam device, and the steam heater and the steam device are connected through the steam opening, so that the resources of the power plant itself can be fully utilized without the need to find additional energy sources, and the utilization rate of steam is improved. , reduce production costs, and have good economic benefits. Of course, setting the opening is convenient for external connection of any steam source, so the pulverizing device has greater selectivity for the steam source used.

The above-mentioned cold-state pulverizing device for coal-fired power plant boilers, wherein the air supply pipe is provided with a switchable cold air inlet.

In the cold-state pulverizing device for a coal-fired power plant boiler as described above, conventional various devices for adjusting the degree of opening and closing of the cold air inlet to adjust the flow of cold air can also be provided at the switchable cold air inlet. Adjustment device.

The flow rate of the incoming cold air can be controlled by the regulating device arranged at the inlet of the cold air, and the temperature of the air fed into the coal mill can be controlled more accurately. Especially when the temperature of the air entering the coal mill is too high and may cause danger, in order to avoid coal powder burning in the coal mill, cold air can be introduced through the switchable cold air inlet to reduce the temperature, thereby avoiding danger.

In summary, the cold-state pulverizing method and pulverizing device provided by the utility model enable the coal mill to start working at the initial stage of boiler ignition to grind coal powder. Therefore, compared with the prior art, it greatly saves the fuel oil consumption in the boiler start-up process, saves precious oil resources, and in addition, the fuel cost is greatly reduced (the calorific value of a unit of diesel oil is about twice that of a unit of coal, But the price of fuel oil (3,000 yuan/ton) is about 15 times that of coal (200 yuan/ton), and the economic benefits are remarkable. Especially, the improvement of the present invention to the prior art has the great significance of saving energy.

Description of drawings

Fig. 1 is a schematic diagram showing a cold furnace pulverizing device of a coal-fired power station boiler according to the present invention;

Fig. 2 is a schematic diagram of an embodiment of the steam heater used in the cold furnace pulverizing device of the coal-fired power plant boiler according to the present invention.

Detailed ways

The specific embodiment of the utility model is described below according to accompanying drawing.

Fig. 1 is a schematic diagram showing an embodiment of a cold furnace pulverizing device for a coal-fired power plant boiler according to the present invention. As shown in Figure 1, the cold furnace pulverization device includes the air supply pipe 1 that sends the hot air for coal grinding into the coal mill 3 and the coal delivery pipe 1 that sends the coal powder in the coal mill 3 to the boiler (send Coal pipelines belong to the prior art and are not shown here). As shown in the figure, according to the utility model, a steam heater 2 is installed on the air supply duct 1 that guides the hot air used for coal grinding into the coal mill 3 . The direction indicated by the arrow in the figure is the direction of supplying hot air to the coal mill. Generally, in a large-scale thermal power plant, one boiler (not shown in the figure) can be equipped with several coal mills 3 at the same time. In Fig. 1, A represents the primary hot air main pipe, which is used to provide hot air for all coal mills 3. The primary hot air main pipe can be connected with a plurality of primary air hot air pipes B, which are used to pass through the air supply pipe 1 for corresponding A coal mill provides hot air. For the sake of simplicity, only one cold furnace pulverizing device of coal mill 3 is shown in detail in Fig. 1 , and the principle of cold furnace pulverizing device with multiple coal pulverizers is similar, so it will not be repeated here. Of course, the steam heater in Fig. 1 can also be arranged in the air supply duct without being connected with the boiler.

As shown in FIG. 2 , the steam heater 2 includes a heating part 21 , a housing 215 that confines the heated air therein, and connecting parts 22 as a part of the housing 215 located on both sides of the heating part 21 . The steam heater 2 is connected to the air supply duct 1 in FIG. It communicates with the air supply duct 1 to form a part of the pipeline for circulating the air used for coal grinding, as shown in Figure 1. The arrows in FIG. 2 indicate the direction in which the air for pulverizing coal passes through the steam heater 2 . The heating part 21 has at least one group of heating elements 213, each group of heating elements 213 is composed of several rows of heating tubes 211, shown in Figure 2 as 2 groups of heating elements 213, each group of heating elements has 4 A row of heating pipes 211, the heating pipes 211 are spaced at a certain distance from each other. The two ends of the heating tube 211 are provided with openings 212, 214 that can introduce and export steam. One of the openings 212, 214 can be selected as the import port of the steam, and the other can be used as the export port. The openings 212, 214 can be connected with, for example, The steam device used in the power plant is connected, so that the steam in the steam device can enter the heating pipe 211 through the openings 212, 214, so that the heating pipe 211 is heated to heat the air entering the steam heater 2. The steam may be isolated from the heated air within the housing 215 .

When starting the boiler, if the boiler is heated by fuel oil or other fuels, it is impossible to increase the overall temperature of the boiler in a short time due to the large size of the boiler. Pipeline 1 enters coal mill 3 .

However, if the air passes through the steam heater 2 arranged in the air supply duct 1 before entering the coal mill 3, and is heated to a high temperature by the heating pipe 211 therein, such as 180° C. to 200° C., it can be used The temperature of the hot air entering the coal mill 3 quickly meets the requirements of heating and drying pulverized coal. In this way, the coal mill can be put into operation at the initial stage of boiler startup, and can grind coal powder earlier, so that the required qualified coal powder can be sent into the boiler through the coal delivery pipeline connected with the boiler instead of fuel oil. Combustion can reduce fuel consumption and production costs.

In actual operation, the steam heater 2 can be provided with a steam heat source through the steam device used in the power plant, so that the heating pipe 211 in the steam heater 2 is in a high temperature state to heat the air in the air supply pipe 1 to be sent into the mill. The coal mill makes the coal mill work. Therefore, the steam utilization rate of the power plant is improved and the production cost is reduced.

Preferably, as shown in FIG. 1 , a switchable cold air inlet 4 can be opened on the air supply duct 1 , and the cold air inlet 4 is closed when not in use. When the temperature of the air heated by the steam heater 2 is too high, the cold air inlet can be opened to deliver the cold air to the air supply duct 1 to neutralize the heat and control the temperature so as not to ignite the gas in the coal mill 3 because the air temperature is too high. Coal dust is dangerous.

In addition, a conventional adjusting device for adjusting the size of the opening can also be provided at the above-mentioned cold air inlet 4, and the air flow of the cold air delivered to the air supply duct 1 can be adjusted by controlling the size of the opening of the cold air inlet. For example, the cold air inlet is formed by a rotating door, and the incoming amount of cold air is adjusted by adjusting the rotation angle of the door.

In order to further save fuel oil, the steam heater can be used to preheat the air before the boiler is ignited, and the hot air is sent into the coal mill; the coal mill is started to work so that coal can be burned when the boiler is ignited.

Although the utility model has been disclosed as above with preferred embodiments, it is not intended to limit the utility model, and any person of ordinary skill in the art may make some changes and modifications without departing from the concept and protection scope of the utility model. Amendments should be based on the scope of claims that define and embody the content of the utility model.

Claims (6)

1. A cold-state pulverizing device for a coal-fired power plant boiler, which includes a coal mill, an air supply pipe for supplying hot air to the coal mill, and a coal delivery pipe for sending coal powder in the coal mill to the boiler , is characterized in that: a steam heater is installed on the air supply duct. 2. The cold-state pulverizing device for a coal-fired power plant boiler as claimed in claim 1, wherein the end of the air supply pipe away from the coal mill is connected to the boiler. 3. The cold-state pulverizing device for coal-fired power plant boilers according to claim 1 or 2, characterized in that, the steam heater includes a heating part and two sides of the heating part for connecting with the air supply pipe The connection part is connected, and the connection part is provided with a connection port communicating with the air supply duct at the end far away from the heating part. 4. The cold-state pulverizing device for coal-fired power plant boiler according to claim 1 or 2, characterized in that, the heating part of the steam heater has at least one set of heating elements, and each set of heating elements has at least It includes several rows of heating tubes, and the heating tubes have openings for introducing and exporting steam, so that the heating tubes can be heated when the steam flows through the heating tubes. 5. The cold-state pulverizing device for a coal-fired power plant boiler according to claim 1 or 2, characterized in that said air supply duct is provided with a switchable cold air inlet. 6. The cold-state pulverizing device for a coal-fired power plant boiler according to claim 5, characterized in that an adjusting device for adjusting the degree of opening and closing of the cold air inlet to adjust the air volume is provided at the cold air inlet.

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