Center injection type on-arch combustion device of W flame boiler
By setting up a central air inlet nozzle and a swing secondary air outlet on the arch of the W-shaped flame boiler, the problem of insufficient stiffness of the primary air jet is solved, and the full extension of the flame and low nitrogen combustion are achieved.
Patent Information
- Application Number
- CN202323538089.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-25
- Publication Date
- 2025-03-18
- Estimated Expiration
- 2033-12-25
AI Technical Summary
In the low nitrogen combustion, existing W-shaped flame boilers have problems such as insufficient primary air jet stiffness, short-circuit flame and poor filling of the lower furnace, which makes it difficult to achieve low nitrogen combustion.
The central arch combustion device is adopted. By setting a central arch-induced air nozzle in the center of the primary air nozzle, the central jet of pure air is sprayed out to supplement the oxygen volume in the early stage of combustion, and the air volume, wind speed and injection angle are adjusted through the swing secondary air nozzle to organize the flow field and oxygen concentration field of the lower furnace.
The stiffness of the primary air jet is improved, so that the flame can fully extend to the lower furnace, and air grading and fuel grading are achieved, achieving the effect of low nitrogen combustion.
Smart Images
Figure CN222634557U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to an arch combustion device of a W-flame boiler, in particular to a central injection type arch combustion device. Background Art
[0002] At present, low-nitrogen combustion technology mainly combines the idea of "air staging" and then realizes "fuel staging" based on the ideas of rich and thin burners. However, most of these low-nitrogen combustion technologies are suitable for tangential combustion boilers and hedge combustion boilers. The flow and combustion process in the W-shaped flame boiler furnace is very different from the above two types of furnaces, and the W-shaped flame boiler burns low-volatile coal, which is more difficult to implement low-nitrogen combustion. The primary air nozzle of the existing W-shaped flame boiler is arranged above the furnace arch, spraying to the lower furnace, and igniting and burning in the high-temperature atmosphere of the lower furnace. However, due to the complexity of the flow and combustion process in the lower furnace of the W-shaped flame boiler, the specific running trajectory of the primary air in the lower furnace is not easy to control accurately, and it often happens that the primary air turns too early, the flame short-circuits, and the filling degree of the lower furnace is not good. If you want to avoid the phenomenon of premature primary air turning, you need to increase the momentum flow rate of the arch wind spraying downward, so that it has a longer range, so that it can penetrate deeper into the lower part of the lower furnace. However, because the primary air contains coal powder, and due to the demand for coal powder ignition, the total air volume of the primary air must match the coal powder in a certain ratio. When the coal type is a low-volatile coal type, the total air volume of the primary air cannot be too high. At this time, if the momentum flow rate of the primary air is to be increased, the wind speed of the primary air must be greatly increased. At this time, the primary air containing a large amount of coal powder will cause many problems such as severe nozzle wear. If the momentum flow rate of the wind on the arch is increased by increasing the flow rate and flow rate of the secondary air nozzle on the arch, because the distance between the primary air and the secondary air on the arch is small, the secondary air will be mixed into the primary air too early, affecting the ignition effect; therefore, these two solutions cannot solve the problem of insufficient downward range of the wind on the arch, so it is difficult for "air classification" and "fuel classification" to achieve the expected effect, and low-nitrogen combustion cannot be achieved. Summary of the invention
[0003] The purpose of the utility model is to provide a W-flame boiler center-injection arch combustion device in view of the above-mentioned deficiencies in the prior art, which can make the primary air jet have better rigidity, enable the flame to fully extend downward to the furnace, effectively implement air staging and fuel staging, and realize low-nitrogen combustion.
[0004] In order to achieve the above-mentioned purpose, the utility model discloses a W-flame boiler center-injection type arch combustion device, comprising a plurality of primary air nozzles, secondary air nozzles and ignition air nozzles arranged on the boiler arch, wherein an ignition gun is arranged in the ignition air nozzle, the secondary air nozzles and the ignition air nozzles are connected to the secondary air box or the secondary air duct, and each primary air nozzle is connected to the primary air duct; the characteristic is that: a center-injection air nozzle is arranged in the primary air nozzle, and the center-injection air nozzle is connected to the air inlet pipe; and each secondary air nozzle is a swing-type secondary air nozzle.
[0005] The primary air nozzle and the central ejection air nozzle may both be circular and concentrically arranged;
[0006] The primary air nozzle and the central ejection air nozzle may also be square and concentrically arranged;
[0007] The primary air nozzles may be double-square nozzles for thick-thin separation, and the square central injection air nozzle is placed between the double-square nozzles for thick-thin separation;
[0008] The utility model arranges a central jet at the center of each primary air nozzle through a central induced air nozzle. The central jet is pure air without coal powder, which not only supplements the oxygen required for the primary air in the early stage of combustion to avoid the poor burnout of low-volatile coal, but also has a higher injection speed and better rigidity, and can guide the primary air energy to fully extend to the lower furnace. In addition, the swing-type secondary air nozzle adjusts the air volume, wind speed and injection angle to spray secondary air, which organizes the flow field and oxygen concentration field in the lower furnace, and can effectively implement air classification and fuel classification to achieve low-nitrogen combustion.
[0009] As a further improvement of the utility model, the angle between the swing-type secondary air nozzle and the vertical line is 0-45°; according to the requirements of the coal type and boiler operating conditions, the injection angle and injection speed of the swing-type secondary air nozzle are adjusted to adjust the flame shape and furnace fullness in real time to obtain the optimal NOx emission level and the heat load distribution of the furnace, providing an important technical means for optimizing the boiler operating conditions;
[0010] In summary, the utility model can make the primary air jet have better rigidity, can make the flame fully extend to the lower furnace, can effectively implement air staging and fuel staging, and realize low-nitrogen combustion. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 It is the front view of the embodiment of the utility model.
[0012] Figure 2 for Figure 1 Front view of embodiment 1 of the middle primary air nozzle and the central induced air nozzle.
[0013] Figure 3 for Figure 1 The front view of the second embodiment of the middle primary air nozzle and the central induced air nozzle.
[0014] Figure 4 for Figure 1 Front view of embodiment 3 of the middle primary air nozzle and the central induced air nozzle. DETAILED DESCRIPTION
[0015] The utility model is further described below in conjunction with the accompanying drawings.
[0016] like Figure 1 , Figure 2 As shown, the W-flame boiler center-injection arch combustion device of this embodiment includes several primary air nozzles 1, secondary air nozzles 2 and ignition air nozzles 3 arranged on the boiler arch, an ignition gun 4 is arranged in the ignition air nozzle 3, the secondary air nozzles 2 and the ignition air nozzles 3 are connected to the secondary air box 9, and each primary air nozzle 1 is connected to the primary air duct 6; a central injection air nozzle 7 is arranged in the primary air nozzle 1, the primary air nozzle 1 and the central injection air nozzle 7 are both circular and concentrically arranged, and the central injection air nozzle 7 is connected to the air inlet pipe 8; each secondary air nozzle 2 is a swinging secondary air nozzle, and the angle between the swinging secondary air nozzle 2 and the vertical line is 0-45°.
[0017] The utility model sprays primary air downward on the furnace arch through several primary air nozzles 1, providing the first-level air for coal powder ignition in air classification; the central induced air nozzle 7 sprays central jet wind at the center of the primary air, the central jet is pure air, does not contain coal powder, the induced air volume accounts for about 4-9% of the total air volume, and provides the second level of air classification. The induced air has a higher injection speed of 40-80m / s, which not only supplements the primary air with the oxygen required in the early stage of combustion, thereby avoiding the poor combustion of low-volatile coal, but also helps the primary air to maintain the jet stiffness, and can guide the primary air energy to fully extend downward to the furnace, thereby maintaining the fullness of the furnace; swing The secondary air ejected from the swing-type secondary air nozzle 2 is located between the primary air and the furnace outlet, providing the third-level air for air classification. The injection angle and injection speed of the swing-type secondary air nozzle 2 can be adjusted according to the requirements of the coal type and boiler operating conditions, so as to adjust the flame shape and furnace fullness in real time, organize the flow field and oxygen concentration field in the lower furnace, so as to obtain the optimal NOx emission level and the heat load distribution of the furnace, and provide an important technical means for optimizing the boiler operating conditions; in addition, the burnout air is arranged above the burner, the under-arch secondary air and exhaust air are arranged under the furnace arch, and the air volume is reasonably distributed, so as to effectively implement air classification and fuel classification and realize low-nitrogen combustion;
[0018] The above embodiments are described, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the present invention to the scope of the described embodiments. For example, the secondary air nozzle 2 and the ignition air nozzle 3 can also be connected to their respective secondary air ducts, such as Figure 3 As shown, the primary air nozzle 1 and the central ejection air nozzle 7 may also be square and concentrically arranged, such as Figure 4 As shown, the primary air nozzle 1 can be a double-square nozzle for thick and thin separation, and the square central induced air nozzle 7 is placed between the double-square nozzles for thick and thin separation; they all fall within the protection scope of this patent.
Claims
1. A W-flame boiler center-injection type arch combustion device, comprising a plurality of primary air nozzles, secondary air nozzles and ignition air nozzles arranged on the boiler arch, wherein an ignition gun is arranged in the ignition air nozzle, the secondary air nozzles and the ignition air nozzles are connected to the secondary air box or the secondary air duct, and each primary air nozzle is connected to the primary air duct; characterized in that: A central induced air nozzle is arranged in each primary air nozzle, and each central induced air nozzle is connected to an air inlet pipe; each secondary air nozzle is a swing type secondary air nozzle.
2. The W-flame boiler center-injection type dome-type combustion device according to claim 1, characterized in that: The primary air nozzle and the central ejection air nozzle are both circular and concentrically arranged.
3. The W-flame boiler center-injection type dome-type combustion device as claimed in claim 1, characterized in that: The primary air nozzle and the central ejection air nozzle are both square and concentrically arranged.
4. The W-flame boiler center-injection type dome-type combustion device according to claim 1, characterized in that: The primary air nozzles are double-square nozzles for thick and thin separation, and the central induced air nozzle is placed between the double-square nozzles for thick and thin separation.
5. The W-flame boiler center-injection type dome-type combustion device according to any one of claims 1 to 4, characterized in that: The angle between the swinging secondary air nozzle and the vertical line is 0-45°.