CN201177258Y - Gas ignition pulverized coal burner - Google Patents

Abstract

The utility model discloses a gas ignited pulverized coal burner which comprises a casing, in which several stages of combustion chambers are arranged, wherein at least two gas igniters are uniformly distributed along the circumferential direction on the primary combustion chamber, and each gas igniter is composed of The ignition chamber and the ejector consist of a gas guide plate, and each ignition chamber is obliquely intersected with the first-stage combustion chamber and fixed at a consistent inclination angle, so that the high-temperature airflow generated by the combustion of each gas igniter is drawn along the oblique direction. The guides are introduced into the first-stage combustion chamber, and cooperate with each other to form a swirling airflow in the first-stage combustion chamber. Compared with the traditional burner, the pulverized coal burner of the utility model does not need to consume fuel oil at all, and only consumes a small amount of gas, thereby achieving the advantages of economy, environmental protection and safety. During operation, it can maintain the original aerodynamic characteristics in the furnace, is safe and reliable, easy to operate and maintain, and has a wide range of coal types. And it is convenient for the oil-saving transformation of the direct current and swirl burners of the pulverized coal furnace.

Description

Gas ignition pulverized coal burner

technical field

The utility model relates to a pulverized coal burner, in particular to a pulverized coal burner for gas ignition.

Background technique

At present, most of the pulverized coal burners in thermal power plant projects are ignited by fuel oil. Fig. 1 is a structural schematic diagram of a micro-oil ignition pulverized coal burner which is widely used at present. The fuel oil combustion chamber 1 is directly inserted into the primary combustion chamber 2 vertically. During operation, the temperature of the lower wall of the primary combustion chamber 2 will be high. At the same time, due to the scouring of the high-speed oil flame, the pulverized coal particles are blocked in the flow, which is easy to cause bottom accumulation. powder, which will lead to coking, so the ignition energy here should not be too large. It is often necessary to install a larger auxiliary oil gun at the outlet of the primary combustion chamber to assist in further combustion, but even this cannot completely solve this defect . For this reason, people try to eliminate the defects of asymmetric arrangement of igniters by arranging two oil igniters symmetrically on the upper and lower sides of the burner. However, after adopting this symmetrical arrangement, a relatively high concentration of pulverized coal still accumulates on both sides of the primary combustion chamber in the horizontal direction, and a large amount of pulverized coal does not enter the core of the high-temperature air flow, resulting in a decrease in the amount of volatile components precipitated from the pulverized coal and causing a Subsequent combustion of the powder has adverse effects.

What's more, this fuel-fired pulverized coal burner consumes a lot of fuel when it works. According to statistics, the boiler of a 125MW unit consumes 15 tons of oil for one start-up, 50 tons of fuel for a start-up of a 200MW unit, and more than 300 tons of fuel oil for ignition and combustion of a 600MW unit boiler. Compared with the lack of oil resources in our country, there are many problems in such high resource consumption, and with the continuous expansion of cities in our country, some thermal power plants that were originally located in the suburbs are now gradually surrounded by cities. Due to environmental protection and safety requirements, these power plants It is not advisable to burn fuel oil to produce a large amount of harmful gas and keep large oil storage tanks. Due to the high penetration rate of gaseous fuels such as liquefied petroleum gas and natural gas in cities in my country, these thermal power plants in urban areas and their surrounding areas are not limited by the storage conditions and transportation conditions of gaseous fuels, and gaseous fuels are used to burn and ignite gaseous fuels. It has the advantages of being more economical, more environmentally friendly, and safer, so it is of practical significance to promote gas fuel combustion ignition technology in this type of power plant.

Utility model content

Aiming at the problems existing in the prior art, the purpose of the utility model is to provide a gas-fired pulverized coal burner.

In order to achieve the above object, a gas-fired pulverized coal burner of the utility model includes a casing, and several stages of combustion chambers are arranged in the casing, wherein at least two gas igniters are uniformly distributed along the circumferential direction on the stage-one combustion chamber, and each gas ignition The injectors are composed of an ignition chamber and an ejector. The ejector includes a gas guide plate. It is introduced into the first-stage combustion chamber obliquely, and cooperates with each other in the first-stage combustion chamber to form a swirling airflow.

Further, the air guide plate is a flat plate structure uniformly distributed with through holes.

Further, each of the ignition chambers is fixedly installed on the same section of the primary combustion chamber, and each ignition chamber is inclined to one side of the circumference of the primary combustion chamber.

Further, each of the ignition chambers is inclined toward the upstream direction of the primary combustion chamber.

Further, the housing is provided with three-stage combustion chambers, and each combustion chamber is connected to each other through supporting ribs, and the entire third-stage combustion chamber is supported and fixed in the housing through the support ribs on the first-stage and third-stage combustion chambers On the wall, on the inner wall of the upstream housing close to the first-stage combustion chamber, a pulverized coal concentration structure with a gradually reduced inner diameter is provided, and on the inner wall of the third-stage combustion chamber, a flame-stabilizing structure with a gradually reduced inner diameter is provided.

Compared with the traditional burner, the pulverized coal burner of the utility model does not need to consume fuel oil at all, and only consumes a small amount of gas, thereby achieving the advantages of economy, environmental protection and safety. During operation, it can maintain the original aerodynamic characteristics in the furnace, is safe and reliable, easy to operate and maintain, and has a wide range of coal types. And it is convenient for the oil-saving transformation of the direct current and swirl burners of the pulverized coal furnace.

Description of drawings

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

Fig. 2 is a structural sectional view of the pulverized coal igniter;

Fig. 3 is a cross-sectional view along line A in Fig. 2 .

Detailed ways

As shown in Figure 2, one, two, and three three-stage combustion chambers 2, 3, and 4 are arranged in the housing 1 of the gas ignition pulverized coal burner of the present utility model, and each combustion chamber is connected to each other by a support rib frame 9, and The entire third-stage combustion chamber is supported and fixed on the inner wall of the shell 1 by the support ribs 8 and 10 on the first-stage and third-stage combustion chambers, and the inner wall of the upstream shell close to the first-stage combustion chamber 2 is provided with pulverized coal whose inner diameter gradually decreases. The concentration structure 7 is provided with a flame-stabilizing structure 11 whose inner diameter gradually decreases on the inner wall of the third-stage combustion chamber 4 . Two gas igniters 12 are evenly distributed along the circumferential direction on the primary combustion chamber 2, and each gas igniter 12 is composed of an ejector 6 and an ignition chamber 5, and a gas guide is provided at the junction of the ejector 6 and the ignition chamber 5. The plate 61 and the gas guiding plate 61 are flat plate structures uniformly distributed with through holes 611, through which the gas can be evenly introduced into the ignition chamber 5, so as to reduce the scour force of the flame when the gas burns. Each ignition chamber 5 is fixedly installed on the same section of the primary combustion chamber 2, and each ignition chamber 5 is not only inclined to one side of the primary combustion chamber 2, but also to the upstream direction of the primary combustion chamber 2. tilt.

During operation, after the primary air-powder mixture enters the housing 1 (primary air duct), it is concentrated by the pulverized coal concentration device 7 to form a pulverized coal airflow that is thick in the middle and light around. The thick pulverized coal airflow enters the primary combustion chamber 2, and the light airflow The pulverized coal flow enters the secondary and tertiary combustion chambers 3 and 4 sequentially from the annular air duct outside the primary combustion chamber 2. On the one hand, staged combustion is realized, and on the other hand, a cooling air film is formed on the inner walls of each combustion chamber to protect the combustion chamber walls. The high-pressure gas enters the gas igniter 12 at a relatively high speed, entrains the surrounding air at the same time, and mixes the speed and concentration in the ejector 6 . In the case of sufficient mixing and uniformity, the mixed gas is evenly introduced into the ignition chamber 5 through the gas guide plate 61 . After being ignited, the mixed gas burns rapidly, and the high-temperature gas and flame produced by the combustion are introduced into the primary combustion chamber 2 obliquely, and cooperate with each other in the primary combustion chamber 2 to form obliquely swirling high-temperature airflow. An air gap is formed in the middle of the obliquely swirling high-temperature airflow, so that the high-concentration pulverized coal airflow can enter the high-temperature airflow (fire core) unimpeded, and fully mix with the high-temperature airflow, so that the pulverized coal particles can be quickly pyrolyzed and burned. Combustion products and combustibles in the primary combustion chamber 2 enter the secondary and tertiary combustion chambers in sequence to realize staged combustion with energy amplification step by step. Finally, the pulverized coal airflow in combustion enters the furnace from the nozzle of the shell 1 (primary air pipe) to realize combustion in the furnace.

Claims (5)

1. A gas-fired pulverized-coal burner includes a housing, which is characterized in that several levels of combustion chambers are arranged in the housing, wherein at least two gas igniters are evenly distributed along the circumference of the first-level combustion chamber, and each gas ignition The injectors are composed of ignition chambers and ejectors. The ejectors include a gas guide plate. It is introduced into the first-stage combustion chamber obliquely, and cooperates with each other in the first-stage combustion chamber to form a swirling airflow. 2. The gas-fired pulverized coal burner according to claim 1, characterized in that, the air guide plate is a flat plate structure uniformly distributed with through holes. 3. The gas-fired pulverized coal burner according to claim 1, characterized in that, each of the ignition chambers is fixedly installed on the same section of the primary combustion chamber, and each ignition chamber faces toward the primary combustion chamber. Circumferentially inclined to one side. 4. The gas-fired pulverized coal burner according to claim 1, characterized in that each of the ignition chambers is also inclined to the upstream direction of the primary combustion chamber. 5. The gas-fired pulverized coal burner according to claim 1, characterized in that three-stage combustion chambers are arranged inside the housing, each combustion chamber is connected to each other through supporting ribs, and the entire three-stage combustion chamber It is supported and fixed on the inner wall of the shell through the supporting ribs on the primary and tertiary combustion chambers. A pulverized coal concentration structure with a gradually reduced inner diameter is arranged on the upstream shell inner wall close to the primary combustion chamber. In the third-stage combustion chamber The inner wall is also provided with a flame-stabilizing structure whose inner diameter gradually decreases.

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