CN201145271Y - Three-stage pulverized coal burner - Google Patents

Abstract

The utility model discloses a three-stage pulverized coal burner, which comprises a mixing passage for conveying pulverized coal and primary air, a combustion stabilization chamber connected to the tail of the mixing passage, and an ignition device extended and arranged at the inlet end of the combustion stabilization chamber. Among them, the combustion chamber includes a first-stage combustion chamber, a second-stage combustion chamber and a third-stage combustion chamber arranged longitudinally, and the first-stage combustion chamber, the second-stage combustion chamber and the third-stage combustion chamber They are all cylindrical structures, and the radial dimension of the second-stage combustion stabilization chamber is larger than the radial dimensions of the first-stage combustion stabilization chamber and the third-stage combustion stabilization chamber. The stable combustion chamber body of the utility model has a stepped structure, which has strong combustion stability, and adopts a graded air-supply swirling combustion method, with high combustion efficiency and low _NOx emissions.

Description

Three-stage pulverized coal burner

technical field

The utility model relates to a combustion device, in particular to a pulverized coal burner.

Background technique

my country is a country that uses coal as its main fuel, and this situation will not change fundamentally for a long time to come. At present, coal accounts for about 70% of China's total energy demand. Low-volatile coal (such as anthracite, lean coal, etc.) and low-quality coal account for a large proportion of China's coal resources. There are some problems in the use of these coals. The reason is that the boiler burner has poor adaptability to coal quality and load changes. When the boiler is operating at high load, the coking in the furnace is serious. When the boiler is operating at low load, the combustion is difficult to stabilize and the burnout rate is low, resulting in waste of energy. and environmental pollution; the second is that the unburned pulverized coal particles will hang on the inner wall of the burner, resulting in coking and high-temperature corrosion, which greatly reduces the service life of the burner; A large amount of NO _x will be produced, which will cause huge pollution to the environment.

As disclosed in Chinese Patent No. CN 93244359.1, a radial thick-lean swirl pulverized coal burner includes a thick pulverized coal channel, a light pulverized coal channel with an annular space and a secondary air with an annular space. Pipeline, the cyclone is installed in the annular space of the secondary air pipe, the inlet of the thick coal powder channel is connected with the thick coal powder outlet channel of the coal powder concentrator through the conveying pipe, and its outlet is connected with the furnace through the burner, and the coal powder is concentrated The inlet of the device is connected to the primary air duct, the entrance of the secondary air duct is connected to the secondary air duct, and its outlet is connected to the furnace. A cyclone is installed in the annular space of the light coal powder channel. However, the pulverized coal wear of the central tube of the radial thick-lean swirling pulverized coal burner is very large, and the tube needs to be replaced frequently, and the pulverized coal concentrator is prone to clogging when the load changes greatly.

Another example is a pulverized coal burner disclosed in Chinese Patent No. CN 98117424.8, which includes a pulverized coal nozzle for injecting a mixture of pulverized coal and primary air, a secondary air nozzle and a tertiary air nozzle, which surround the pulverized coal nozzle. Arranged coaxially at the outer periphery, and a duct extension at the end of the partition wall separating two adjacent air nozzles; providing a flow changing device for transforming the secondary air in the secondary air nozzle so that the secondary air expands along the duct Partial flow. Due to the outward injection of the secondary air by the guide plate, the mixing of the secondary air, the tertiary air and the pulverized coal is delayed, and the amount of NO _x produced thereby is reduced. Although this kind of pulverized coal burner can effectively reduce the emission of _NOx , it has poor adaptability to coal types, poor combustion stability for low-volatile coal and low-quality coal that are difficult to ignite, and there is also the problem of severe wear of pulverized coal nozzles. question.

In view of the continuous improvement of China's environmental protection requirements and the fact that a large number of low-volatility coal and low-quality coal that are difficult to catch fire, stable combustion, and more difficult to burn can not be effectively utilized in the Chinese market, a coal type with strong adaptability and a large load adjustment range is provided. Pulverized coal burners with low _NOx emissions, high combustion efficiency and long service life have become problems that the industry needs to solve.

Contents of the invention

The purpose of the utility model is to provide a three-stage pulverized coal burner with strong low-load stable combustion capability, good coal type adaptability, high combustion efficiency and low NO _x emission.

The technical scheme of the utility model is achieved by providing a three-stage pulverized coal burner, including a mixing channel for conveying pulverized coal and primary air, a combustion stabilization chamber connected to the tail of the mixing channel, and a combustion stabilization chamber extended to The ignition device at the entrance of the chamber, wherein the combustion chamber includes a longitudinally arranged first-stage combustion chamber, a second-stage chamber and a third chamber, the first chamber, the second chamber and The third-stage combustion stabilization chambers are all cylindrical structures, and the radial dimension of the second-stage combustion stabilization chamber is larger than the radial dimensions of the first-stage combustion stabilization chamber and the third-stage combustion stabilization chamber.

Preferably, the first-stage combustion stabilization chamber, the second-stage combustion stabilization chamber and the third-stage combustion stabilization chamber are roughly arranged on the same axis.

More preferably, the first-stage combustion stabilization chamber is provided with two or more first-stage secondary air ducts along the tangential direction for delivering the first-stage secondary air into the first-stage combustion stabilization chamber. Two or more second-stage secondary air pipes for delivering second-stage secondary air into the second-stage combustion-stabilizing chamber are arranged along the tangential direction in the second-stage combustion-stabilizing chamber. The third-stage combustion stabilization chamber is provided with two or more third-stage secondary air pipes for delivering the third-stage secondary air into the third-stage combustion stabilization chamber along the tangential direction.

Wherein, the radial dimension of the third-stage combustion stabilization chamber is larger than the radial dimension of the first-stage combustion stabilization chamber. Optionally, the radial dimension of the second-stage combustion stabilization chamber is 1.5 to 3 times the radial dimension of the first-stage combustion stabilization chamber, such as 1.8 times or 2 times; the radial dimension of the third-stage combustion stabilization chamber is the first 1 to 1.5 times, such as 1.2 or 1.3 times, the radial dimension of the primary stable combustion chamber.

Optionally, the longitudinal dimension of the second-stage combustion stabilization chamber is 1 to 2 times the longitudinal dimension of the first-stage combustion stabilization chamber, such as 1.2 times or 1.5 times; the longitudinal dimension of the third-stage combustion stabilization chamber is the first-stage stabilization chamber. 1 to 2 times the longitudinal size of the combustion chamber, such as 1.5 or 2 times.

Preferably, a tertiary air channel is further provided, the tertiary air channel is arranged around the outer wall of the stabilizing chamber and extends from the inlet end of the stabilizing chamber to the outlet end of the stabilizing chamber. More preferably, the tail of the tertiary air channel shrinks inward to form a conical section.

Preferably, spoiler vanes are provided at the connection between the mixing channel and the first-stage combustion stabilization chamber.

Specifically, the ignition device includes an oil ignition gun, the end of the oil ignition gun is extended to the center of the inlet end of the stable combustion chamber, and the spoiler vanes are arranged around the oil ignition gun.

The using method of the third-order pulverized coal burner of the present utility model is as follows: (1), transport pulverized coal and account for the primary wind of 5%～15% of the total amount of air needed for the complete combustion of pulverized coal to the stable combustion chamber through the mixing channel; (2) ), through the first-stage secondary air pipe to deliver the first-stage secondary air that accounts for 10% to 20% of the total amount of air required for the complete combustion of pulverized coal to the first-stage stable combustion chamber; (3), through the second-stage The secondary air pipe transports the secondary air of the second stage accounting for 45% to 55% of the total amount of air required for the complete combustion of pulverized coal to the second-stage stable combustion chamber; (4), through the third-stage secondary air pipe to the The third-stage secondary air that accounts for 20% to 30% of the total amount of air required for complete combustion of pulverized coal is transported in the three-stage stable combustion chamber; (5) Start the ignition device to ignite. Wherein, according to specific needs, the above steps can be performed synchronously or step by step, and the execution order of each step is not limited by the above arrangement order.

Preferably, before the mixture of pulverized coal and primary air enters the stabilizing chamber, spoiler blades are used to make the mixture of pulverized coal and primary air swirl. More preferably, the method further includes delivering tertiary air into the tertiary air duct.

In the utility model, the air required for pulverized coal combustion is divided into five levels of air supply, which are primary air, first level secondary air, second level secondary air, third level secondary air and tertiary air, among which The primary wind, the first secondary air, the second secondary air and the third secondary air are swirling winds, and the primary wind realizes swirling through spoiler blades. The first-stage secondary air, the second-stage secondary air, and the third-stage secondary air enter the first stage tangentially through the first-stage secondary air pipe, the second-stage secondary air pipe, and the third-stage secondary air pipe respectively. The first-stage stable combustion chamber, the second-stage stable combustion chamber and the third-stage stable combustion chamber realize the swirling flow. Among them, the role of the first level of secondary air is to ignite and support combustion, the role of the second level of secondary air is to achieve strong swirl and stable combustion, and the role of the third level of secondary air is to make the pulverized coal burn. The tertiary air channel is installed around the outer wall of the burner, and the tertiary air in it is straight air, and its function is to cool the outer wall of the burner on the one hand, and to adjust the shape of the flame produced by the burner on the other hand.

The beneficial effects of the utility model are as follows: 1. The body of the stabilizing combustion chamber has a stepped structure, which has strong combustion stabilizing properties, and adopts the staged air supply swirl combustion mode, which has high combustion efficiency and low NO _x emission. 2. By adjusting the air volume of each chamber, it has a very strong combustion stability ability for the low-load operation of the boiler, because the first-stage combustion chamber, the second-stage combustion chamber and the third-stage combustion chamber are all heat-insulating structures, which have good The function of heat preservation and stable combustion is an excellent heat storage body and a stable ignition source. The minimum load can be adjusted to less than 1/3, and it has dual functions of ignition and enhanced combustion; by controlling the oxygen in each stable combustion chamber concentration to avoid the occurrence of high-temperature coking, and at the same time suppress the formation of _NOx ; 3. An air-cooled jacket (that is, a tertiary air duct) is installed around the burner, and the tertiary air flow of the air-cooled jacket can be adjusted according to needs Prevent overheating of the burner wall to prevent high-temperature corrosion; 4. There is no central tube and other mechanical parts in the heat exchange space of the burner, and no obvious wear occurs, which further improves the service life of the burner.

Below in conjunction with accompanying drawing and embodiment, the utility model is further described, but the utility model is not limited to these embodiments, and any improvement or substitution on the basic spirit of the utility model still belongs to the requirement in the claims of the utility model scope of protection.

Description of drawings

Fig. 1 is the structural representation of the utility model pulverized coal burner.

Detailed ways

Example 1

Please refer to Figure 1, the pulverized coal burner of the present invention includes a mixing channel 1, a spoiler vane 2 arranged at the tail of the mixing channel, a small ignition oil gun 3, a first-stage stable combustion chamber 4, and a first-stage secondary air duct 5. Second-level combustion chamber 6, second-level secondary air duct 7, third-level combustion chamber 8, third-level secondary air duct 9, and tertiary air duct 10. Wherein, the first-stage stable combustion chamber 4, the second-stage stable combustion chamber 6 and the third-stage stable combustion chamber 8 are all cylindrical structures located on the same axis, and the first-stage stable combustion chamber 4, the second The primary combustion stabilization chamber 6 and the third combustion stabilization chamber 8 are longitudinally distributed to form a combustion stabilization chamber.

Wherein, the radial dimension of the second-stage combustion stabilization chamber 6 is larger than the radial dimension of the third-stage combustion stabilization chamber 8 , and the radial dimension of the third-stage combustion stabilization chamber 8 is larger than the radial dimension of the first-stage combustion stabilization chamber 4 . Specifically, the radial dimension of the second-stage combustion stabilization chamber 6 is about twice the radial dimension of the first-stage combustion stabilization chamber 4; the radial dimension of the third-stage combustion stabilization chamber 8 is approximately 1.2 times the radial dimension.

In addition, the longitudinal dimension of the second-stage combustion stabilization chamber 6 is about 1.2 times the longitudinal dimension of the first-stage combustion stabilization chamber 4; the longitudinal dimension of the third-stage combustion stabilization chamber 8 is also about 1.2 times the longitudinal dimension of the first-stage combustion stabilization chamber 1.2 times.

Among them, the mixture of primary air and coal powder enters the first-stage stable combustion chamber 4 through the swirling flow of the interfering flow vane 2 in its mixing channel 1, and the coal powder in the first-stage stable combustion chamber 4 is ignited by the ignition oil gun 2 , at the initial stage of pulverized coal ignition and combustion, only part of the secondary air is added, that is, the first-stage secondary air, the first-stage secondary air is tangentially directed from the first-stage secondary air pipe 5 to the first-stage stable combustion chamber 4 High-speed jetting, the pulverized coal forms a fuel-rich combustion vortex area under the action of the high-speed rotating first-stage secondary air, causing the pulverized coal to ignite rapidly. The airflow after ignition enters the second-stage combustion chamber 6, and under the strong action of the second-stage secondary wind of the high-speed swirling flow, a vortex area is formed at the four corners of the second-stage combustion chamber, and a local high-temperature area is formed in the vortex area, which has Very strong stabilizing effect. The high-temperature flue gas rotating at high speed enters the third-stage stable combustion chamber 8, which is the burning area of pulverized coal, and the third-stage secondary air pipe 9 is installed in it, so that the pulverized coal can be completely burned here. Combustion greatly reduces the carbon content of fly ash. A tertiary air duct 10 is installed around the outer wall of the combustion chamber, and the tertiary air is straight air. Its function is to adjust the shape of the flame on the one hand, and on the other hand to avoid overheating of the combustion chamber wall and prevent high temperature corrosion.

The working principle of the utility model is: after the mixture of primary wind and coal powder enters the first-stage stable combustion chamber 4 through the swirling flow of the interfering flow blade 2, the coal powder in the first-stage stable combustion chamber 4 is ignited by the ignition oil gun 3 . At the initial stage of pulverized coal ignition and combustion, only part of the secondary air is added, that is, the first-stage secondary air. Under the action of the high-speed rotating first-stage secondary air, the pulverized coal forms a vortex area rich in fuel combustion, making the pulverized coal Quickly catch fire. The primary air accounts for about 10% of the air required for complete combustion of pulverized coal, and the first-stage secondary air accounts for about 15% of the air required for complete combustion of pulverized coal. A reducing atmosphere, thereby effectively suppressing the formation of fuel-type NO _x . The airflow after ignition enters the second-stage stable combustion chamber, and under the strong action of the second-stage secondary wind of the high-speed swirling flow, a vortex area is formed at the four corners of the second-stage combustion chamber 6, and a local high-temperature area is formed in the vortex area, which has the characteristics of Strong combustion stabilizing effect. By adjusting the air volume, the inside of the second stage stabilizing chamber 6 is also in an oxygen-lean combustion state. The excess air coefficient is less than 0.8, and the temperature does not exceed 1200°C, which can further suppress the generation of thermal _NOx . The secondary air accounts for about 50% of the air required for the complete combustion of pulverized coal. The high-temperature flue gas rotating at high speed enters the third-stage stable combustion chamber 8, which is the burning zone of pulverized coal, and a third-stage secondary air duct is installed in it to make the pulverized coal completely burnt here. Ember, greatly reducing the carbon content of fly ash. The tertiary air flows around the outer wall of the combustion chamber. The tertiary air is straight air, and the end of the tertiary air duct 10 is a contracted conical section. The shape is adapted to different boilers. Another function of the tertiary air is to cool the outer wall of the combustion chamber.

Example 2

Please refer to Fig. 2, as another kind of scheme of the present utility model, other parts are identical with embodiment 1, difference is:

The tertiary air duct 10 is not adopted. The radial dimension of the second-stage combustion stabilization chamber 6 is about 1.5 times the radial dimension of the first-stage combustion stabilization chamber 4; the radial dimension of the third-stage combustion stabilization chamber 8 is about the radial dimension of the first-stage combustion stabilization chamber 4 1.1 times. The longitudinal dimension of the second-stage combustion stabilization chamber 6 is about 1.5 times of the longitudinal dimension of the first-stage combustion stabilization chamber 4; the longitudinal dimension of the third-stage combustion stabilization chamber 8 is also about 1.5 times of the longitudinal dimension of the first-stage combustion stabilization chamber 4 .

The primary air accounts for about 15% of the total air required for the complete combustion of pulverized coal. The first secondary air accounts for about 20% of the total air required for the complete combustion of pulverized coal. The secondary air of the second stage accounts for about 40% of the total amount of air required for the complete combustion of pulverized coal. The third secondary air accounts for about 25% of the total amount of air required for the complete combustion of pulverized coal.

Example 3

As another kind of scheme of the present utility model, other parts are identical with embodiment 1, and difference is:

The first-stage combustion chamber 4 is provided with two first-stage secondary air ducts 5, the second-stage combustion chamber 6 is provided with four second-stage secondary air pipes 7, and the third-stage combustion chamber 8 is provided with three third air ducts. Secondary air duct 9.

The radial dimension of the second-stage combustion stabilization chamber 6 is about 1.5 times the radial dimension of the first-stage combustion stabilization chamber 4; the radial dimension of the third-stage combustion stabilization chamber 8 is about the radial dimension of the first-stage combustion stabilization chamber 4 1.1 times. The longitudinal dimension of the second-stage combustion stabilization chamber 6 is about 1.5 times of the longitudinal dimension of the first-stage combustion stabilization chamber 4; the longitudinal dimension of the third-stage combustion stabilization chamber 8 is also about 1.5 times of the longitudinal dimension of the first-stage combustion stabilization chamber 4 .

The primary air accounts for about 8% of the total air required for the complete combustion of pulverized coal. The first secondary air accounts for about 10% of the total air required for the complete combustion of pulverized coal. The secondary air of the second stage accounts for about 60% of the total amount of air required for the complete combustion of pulverized coal. The third secondary air accounts for about 22% of the total amount of air required for the complete combustion of pulverized coal.

Claims (10)

1. A three-stage pulverized coal burner, comprising a mixing passage for conveying pulverized coal and primary air, a combustion stabilization chamber connected to the tail of the mixing passage, and an ignition device extending from the inlet end of the combustion stabilization chamber, It is characterized in that the combustion stabilization chamber includes a first-stage combustion stabilization chamber, a second-stage combustion stabilization chamber and a third-stage combustion stabilization chamber arranged longitudinally, the first-stage combustion stabilization chamber, the second-stage combustion stabilization chamber The chamber and the third-stage combustion stabilization chamber are both cylindrical structures, and the radial dimension of the second-stage combustion stabilization chamber is larger than the radial dimension of the first-stage combustion stabilization chamber and the third-stage combustion stabilization chamber. size. 2. The three-stage pulverized coal burner according to claim 1, characterized in that the first-stage combustion stabilization chamber is provided with two or more The first-stage secondary air duct that conveys the first-stage secondary air inside. 3. The three-stage pulverized coal burner according to claim 1, characterized in that, the second-stage combustion stabilization chamber is provided with two or more The second-stage secondary air duct that conveys the second-stage secondary air inside. 4. The three-stage pulverized coal burner according to claim 1, characterized in that the third-stage combustion stabilization chamber is provided with two or more The third-stage secondary air duct that conveys the third-stage secondary air inside. 5. The three-stage pulverized coal burner according to any one of claims 1-4, characterized in that the radial dimension of the second-stage combustion stabilization chamber is 1.5 times the radial dimension of the first-stage combustion stabilization chamber. times to 3 times, the radial dimension of the third-stage combustion stabilization chamber is 1 to 1.5 times the radial dimension of the first-stage combustion stabilization chamber. 6. The three-stage pulverized coal burner according to any one of claims 1 to 4, characterized in that, the longitudinal dimension of the second-stage combustion stabilization chamber is 1 time to the longitudinal dimension of the first-stage combustion stabilization chamber. 2 times, the longitudinal dimension of the third-stage combustion stabilization chamber is 1 to 2 times the longitudinal dimension of the first-stage combustion stabilization chamber. 7. The three-stage pulverized coal burner according to any one of claims 1-4, characterized in that a tertiary air duct is further provided, the tertiary air duct is arranged around the outer wall of the stable combustion chamber and passes from the stable combustion chamber to The inlet end of the combustion chamber extends to the outlet end of the stabilization chamber. 8. The three-stage pulverized coal burner according to claim 7, characterized in that, the tail of the tertiary air channel shrinks inward to form a conical section. 9. The three-stage pulverized coal burner according to any one of claims 1-4, characterized in that spoiler blades are provided at the connection between the mixing channel and the first-stage combustion chamber. 10. The three-stage pulverized coal burner according to claim 9, wherein the ignition device includes an ignition oil gun, and the end of the ignition oil gun is extended to the center of the inlet end of the stable combustion chamber, so that The spoiler vane is arranged around the ignition oil gun.

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