CN201103900Y - Pulverized coal burner for tiny oil ignition - Google Patents

Abstract

The utility model discloses a coal powder burner of tiny-oil igniting, which comprises a primary air channel (1), a coal powder concentrator (2) and a coal powder combustion chamber (6) which are successively communicated and are provided with a coincident central axix; wherein, at least two oil combustion chambers (4) are symmetrically arranged on the coal powder concentrator (2); each inlet end (41) of each oil combustion chamber (4) is connected with a tiny-oil gun (3), and each outlet end (43) of the oil combustion chamber (4) is communicated with the coal powder concentrator (2); angels of 40 to 60 degrees are formed between the central axis (42) of the oil combustion chamber (4) and a central axis (11) of the primary air channel (1). The ignition time of fuels can be greatly shortened with the help of the coal powder burner of tiny-oil igniting.

Description

A Micro-oil Ignition Pulverized Coal Burner

technical field

The utility model relates to a pulverized coal burner, which belongs to a cold-state ignition and ultra-low-load stable combustion device for a pulverized coal boiler in a power station; in particular, it relates to a pulverized coal burner for micro-oil ignition.

Background technique

my country is a big oil importing country. In May 2005, the National Development and Reform Commission launched the "Medium and Long-term Special Plan for Energy Conservation", which proposed the goal of saving and replacing 38 million tons of oil during the "Eleventh Five-Year Plan" period, and was listed as the top ten energy-saving projects. The conventional method for boiler start-up and low-load stable combustion in a thermal power station is to use a large oil gun to inject oil; taking a 300MW unit as an example, 50-100T of fuel oil needs to be input during the cold start-up of the boiler from ignition to pulverized coal with load. With the use of micro-oil ignition and combustion-supporting technology, according to the principle of step-by-step energy amplification, a small amount of pulverized coal can be directly ignited with a high-energy oil gun, and then more pulverized coal can be ignited step by step; thus, a small amount of oil can be used to start the cold furnace of the boiler. The purpose of boiler ignition is to use a small amount of oil to stabilize the boiler combustion when the boiler is shut down, low load and ultra-low load; according to different types of coal, the fuel saving effect can generally reach 70-98%. At present, our country has achieved quite a lot of achievements in the field of micro-oil ignition technology and accumulated rich experience. Chinese patent ZL03255982.8, ZL200520145352.2 etc. have announced several different forms of micro-oil ignition burners, and these burners have their own advantages in realizing micro-oil ignition and low-load stable combustion; but the pulverized coal of these burners The combustion chambers are generally circular nozzles, and the oil guns are arranged on one side. Since this type of burner adopts the method of arranging oil guns on one side, the heating of the pulverized coal is single-sided heating; this results in a long heating time and requires a longer size of the entire pulverized coal burner. This is difficult for quite a lot of power plants, because for power plants that have been put into operation, the position where the entire pulverized coal burner is placed (that is, the position of the interface flange of the primary air duct and the interface flange position of the pulverized coal combustion chamber ) has been fixed, that is, the upper limit of the length of the entire pulverized coal burner has been determined. Therefore, when the actual required length of the entire pulverized coal burner exceeds the upper limit, the burnout rate of pulverized coal at the outlet of the burner will be reduced; this will greatly reduce the stability of ignition, and even cause normal ignition. Therefore, the above-mentioned existing burners only have good adaptability to bituminous coal and lignite with high volatile content, and their application is relatively limited.

Utility model content

The technical problem to be solved by the utility model is to provide a pulverized coal burner which can greatly shorten the ignition time of fuel.

In order to solve the above technical problems, the utility model provides a micro-oil ignition pulverized coal burner, which includes a primary air passage, a pulverized coal concentrator and a pulverized coal combustion chamber connected in sequence and whose central axes overlap. At least two oil combustion chambers are arranged symmetrically, the inlet end of each oil combustion chamber is connected with a micro-oil gun, and the outlet end is connected with the pulverized coal concentrator; the central axis of the oil combustion chamber is connected with the central axis of the primary air channel Form an included angle of 40° to 60°.

As an improvement of the micro-oil ignition pulverized coal burner of the present utility model: the pulverized coal concentrator is composed of a tapered section on the left side, a throat section in the middle and a gradually expanding section on the right side, forming a large left and right ends and a small middle section. The pipe; the left tapering section is connected with the primary air passage, and the right tapering section is connected with the pulverized coal combustion chamber; the oil combustion chamber is arranged on the right tapering section.

As a further improvement of the micro-oil ignition pulverized coal burner of the utility model: the area of the inlet end of the oil combustion chamber≤the area of the outlet end.

As a further improvement of the micro-oil ignition pulverized coal burner of the utility model: the inlet end is round, and the outlet end is waist round.

The micro-oil ignition pulverized coal burner of the present utility model adopts the symmetrical arrangement of double oil guns (or multiple oil guns), so it avoids the disadvantage of unfavorable heating of the far-end fuel when the oil guns are arranged on one side, and overall Reduced warm-up time before fuel ignites. Therefore, the preheating, drying and ignition of fuel can be completed within a shorter distance, greatly improving the stability of ignition, and avoiding the lack of ignition stability and coal burning caused by the insufficient length of the entire pulverized coal burner to the greatest extent. The problem of low powder burnout rate. Using the micro-oil ignition pulverized coal burner of the utility model can improve the burnout rate of the pulverized coal under the condition that the length of the entire micro-oil ignition pulverized coal burner remains unchanged. Therefore, the micro-oil ignition pulverized coal burner of the present utility model can be used as an ignition burner, but also as a main burner and a low-load stable burning burner.

Description of drawings

Below in conjunction with accompanying drawing, the specific embodiment of the present utility model is described in further detail.

Fig. 1 is the sectional structure schematic diagram of micro-oil ignition pulverized coal burner of the present utility model;

FIG. 2 is a schematic right view of FIG. 1 .

Detailed ways

Figure 1 and Figure 2 combine to provide a micro-oil ignition pulverized coal burner, including a pulverized coal concentrator 2, a primary air channel 1 with a square cross section and a pulverized coal combustion chamber 6 with a square cross section. The pulverized coal concentrator 2 is composed of a left side tapering section 21, a middle throat section 22 and a right side tapering section 23 connected successively from left to right; the longitudinal section of the left side tapering section 21 is large at the left end and small at the right end isosceles trapezoid, the longitudinal section of the gradual expansion section 23 on the right is an isosceles trapezoid with a small left end and a large right end; therefore the whole pulverized coal concentrator 2 is a pipeline with large left and right ends and small middle. The left tapering section 21 communicates with the primary air passage 1, and the right tapering section 23 communicates with the pulverized coal combustion chamber 6; therefore, the cross sections of the left tapering section 21 and the right expanding section 23 are square. The central axis 11 of the primary air channel 1 , the central axis of the left tapering section 21 , the central axis of the middle throat section 22 , the central axis of the right expanding section 23 and the central axis of the pulverized coal combustion chamber 6 coincide. The above structure of the pulverized coal concentrator 2 can ensure the rapid heating of the pulverized coal by the oil combustion flame without increasing the resistance of the entire burner too much.

A cylindrical cooling air chamber 5 is arranged on the periphery of the entire pulverized coal concentrator 2 and the pulverized coal combustion chamber 6 , that is, the entire pulverized coal concentrator 2 and the pulverized coal combustion chamber 6 are located in the inner cavity of the cooling air chamber 5 . The bottom of the cooling air chamber 5 is sealed to the outer wall of the left tapered section 21; the top 51 of the cooling air chamber 5 is open, and the top 51 of the cooling air chamber 5 is flush with the outlet 61 of the pulverized coal combustion chamber 6.

Two oil combustion chambers 4 are arranged symmetrically on the right diverging section 23 ; that is, the outlet end 43 of each oil combustion chamber 4 communicates with the right diverging section 23 . When the cross-section of the right side diverging section 23 is a rectangle, the oil combustion chamber 4 should be arranged on the long side corresponding to the rectangle; like this, the distance between the two oil combustion chambers 4 is relatively close, reducing the penetration distance of the torch. The oil combustion chamber 4 is located in the inner cavity of the cooling air chamber 5 . The micro oil gun 3 passes through the side wall of the cooling air chamber 5 and communicates with the inlet end 41 of the oil combustion chamber 4; The central axis of the micro-oil gun 3 coincides with the central axis 42 of the oil combustion chamber 4, and the central axis 42 of the oil combustion chamber 4 forms an included angle of 40° to 60° with the central axis 11 of the primary air passage 1, for example, it can be 50° ° angle. The area of the inlet port 41 of the oil combustion chamber 4 ≤ the area of the outlet port 43 ; for example, the area of the outlet port 43 may be 1.5 times the area of the inlet port 41 . The inlet end 41 is designed as a circle, and the outlet end 43 is designed as a waist circle. Both the circle and the waist are perpendicular to the central axis 42 of the oil combustion chamber 4, and the centerlines of the circle and the waist coincide with the central axis 42; and the circle gradually transitions to the waist smoothly. The length of the minor axis of the waist circle can be equal to the diameter of the circle. This structure can maximize the contact area between the oil flame and the pulverized coal, so as to make full use of the heat of the fuel flame to heat the pulverized coal.

In FIG. 1 , for clarity of expression, one of the oil combustion chambers 4 is processed in section.

Situation during actual work of the micro-oil ignition pulverized coal burner of the present utility model is as follows:

Cooling air is injected from the top 51 of the cooling air chamber 5 to cool the wall surfaces of the pulverized coal concentrator 2 and the pulverized coal combustion chamber 6 located in the inner chamber of the cooling air chamber 5 to prevent the wall temperature from being too high. The heated cooling air still flows out from the top 51 of the cooling air chamber 5 .

The primary air carries pulverized coal into the primary air passage 1, and when passing through the middle throat section 22, the pulverized coal airflow is concentrated. When further passing through the right side gradual expansion section 23, according to the principle of inertia, when the flow section of the pulverized coal flow suddenly expanded, the dense pulverized coal flow would maintain inertia and concentrate in the middle of the pulverized coal combustion chamber 6 (that is, close to the pulverized coal combustion chamber 6 central axis), and the light pulverized coal flow will be deflected and concentrated to the wall of the pulverized coal combustion chamber 6. In this way, the oil flame ejected from the oil combustion chamber 4 will directly scour to the upper and lower sides of the dense pulverized coal airflow, forming a violent mass transfer and heat transfer process, so that the pulverized coal heats up rapidly and burns; finally, from the pulverized coal combustion chamber 6 Outlet 61 ejects. Due to the hedging arrangement of double oil guns, compared with the traditional single oil gun arrangement, the pulverized coal is ignited on both sides, which is fast and stable. On the other hand, when a single oil gun is arranged, due to the momentum of the oil flame, the main pulverized coal airflow will be blown away and the aerodynamic structure in the pulverized coal combustion chamber 6 will be destroyed, thereby causing the pulverized coal combustion chamber 6 opposite to the oil gun to burn. Overheating or even slagging of the wall surface is a common problem in the actual operation process in the past. The micro-oil ignition pulverized coal burner of the present utility model can fundamentally solve this problem due to the use of double oil guns against the arrangement, and can greatly improve the aerodynamic working conditions inside the pulverized coal combustion chamber 6, so that the coal The inside of the pulverized coal combustion chamber 6 has a good flame fullness, which can basically eliminate the vortex area and dead stagnation area, and avoid the large thermal stress on the wall of the pulverized coal combustion chamber 6 to reduce the strength. Furthermore, the concentration of the light pulverized coal flow at the wall of the pulverized coal combustion chamber 6 can effectively prevent the excessive temperature of the pulverized coal combustion chamber 6 walls, thereby protecting the pulverized coal combustion chamber 6 and avoiding slagging of the pulverized coal combustion chamber 6 wall surfaces role.

Finally, it should also be noted that what is listed above is only a specific embodiment of the present invention. Apparently, the utility model is not limited to the above embodiments, and many variations are possible. All deformations that a person skilled in the art can derive or associate directly from the content disclosed in the utility model shall be considered as the protection scope of the utility model.

Claims (4)

1. A micro-oil ignition pulverized coal burner, comprising a primary air channel (1), a pulverized coal concentrator (2) and a pulverized coal combustion chamber (6) connected successively and coincident with the central axis, characterized in that: The pulverized coal concentrator (2) is symmetrically provided with at least 2 oil combustion chambers (4), and the inlet port (41) of each oil combustion chamber (4) links to each other with a micro-oil gun (3), and the outlet port ( 43) communicate with the pulverized coal concentrator (2); the central axis (42) of the oil combustion chamber (4) and the central axis (11) of the primary air passage (1) form an included angle of 40° to 60°. 2. The micro-oil ignition pulverized coal burner according to claim 1, characterized in that: the pulverized coal concentrator (2) is sequentially connected to the left taper section (21) and the middle throat section (22) and the right gradual expansion section (23), forming a pipeline with large left and right ends and a small middle; the left tapered section (21) is connected with the primary air channel (1), and the right gradual expansion section (23) is connected with the coal The powder combustion chamber (6) is connected; The oil combustion chamber (4) is set on the right side diverging section (23). 3. The micro-oil ignition pulverized coal burner according to claim 2, characterized in that: the area of the inlet port (41) of the oil combustion chamber (4)≤the area of the outlet port (43). 4. The micro-oil ignition pulverized coal burner according to claim 3, characterized in that: the inlet end (41) is round, and the outlet end (43) is waist round.

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