JPS6218803Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a burner device that reduces the amount of nitrogen oxides generated.

In recent years, nitrogen oxides have become important as air pollutants, but in order to reduce nitrogen oxides, it is essential to suppress the flame temperature, and in particular, to reduce the peak temperature of the flame that appears immediately after the flame ignites. It is known that a large reduction effect on nitrogen oxides can be obtained with this method.

Currently, 2 is being adopted in commercial boilers as a measure to reduce nitrogen oxides (hereinafter referred to as NOx).
In the staged combustion method, the amount of combustion air from the burner throat is kept below the theoretical amount, and the remaining required air amount is supplemented from another throat located on the side wall of the furnace, thereby lowering the flame temperature and reducing the production of nitrogen oxides. However, this method tends to cause flame instability, and the ratio between the amount of air from the burner throat and the theoretical amount of air cannot be made sufficiently small. There is a certain limit to the effect of reducing nitrogen oxides, as it is impossible to reduce the amount of nitrogen oxides. On the other hand, an exhaust gas recirculation method is also being adopted in which combustion exhaust gas is introduced through the burner throat to lower the flame temperature by reducing O ₂ .This method has the same effect of reducing nitrogen oxides as the two-stage combustion method, but the equipment cost is very high. has the disadvantage of being expensive.

In burner equipment, there are strong demands for high-load combustion, the ability to handle a wide range of loads, and flame stability. , a means for supplying as tertiary air is disclosed.

For example, in Japanese Patent Publication No. 42-12377, the primary air surrounding the burner is given a strong swirl and the amount of air is controlled, and the amount of secondary air that surrounds the mixture of primary air and fuel and is not swirled is independently controlled. It is said to stabilize the flame by controlling it. Further, the amount of tertiary air is controlled by a damper that is linked to a damper that controls the amount of secondary air supplied, and the tertiary air is combusted in the preheating combustion chamber and supplied to the furnace. However, in this device, the provision of a pre-combustion chamber to improve the mixing of air and fuel and to maintain the flame is an essential condition for this invention, which is intended for small boilers with a small furnace volume. Note that the structure and link mechanism are complicated, and in addition, there are problems such as burnout of members due to the high temperature of the preheating chamber.

In addition, as a device without a pre-combustion chamber, the special public
As shown in No. 16873, there is a system in which swirling vanes are used to give swirling, similar to the above example, and the amount of secondary air is controlled in accordance with the amount of supplied oil. In this case, only the primary and secondary air quantities correspond to the oil quantities, and the tertiary air is not taken into account, so it cannot be said to be suitable for a large-capacity burner.

This idea attempts to solve the shortcomings of conventional combustion equipment in reducing nitrogen oxides, and its purpose is to be able to use it in large-capacity burners and obtain a more effective nitrogen oxide reduction than conventional ones with a stable flame. The present invention provides a burner device which is simple in structure and easy to control.

In short, this device controls the total amount of primary and secondary air supplied, controls the amount of primary air supplied without swirling it, controls the swirling speed of the secondary air, and in addition, controls the amount of tertiary air. The present invention is characterized by proposing a structure in which the amount of NOx generated is reduced by controlling the amount of NOx in one burner device.

An embodiment of this invention will be described below with reference to the drawings. Among the combustion air, the primary and secondary air flows as one air flow from the air port 9 of the outer cylinder 8 in the wind box 3 to the passage between the outer cylinder and the end of the cylindrical primary air amount adjustment damper 6. , and then the primary air amount adjustment damper 6
The primary air _A1 is branched and flows into the inner cylinder 7 from the passage between the rear end of the inner cylinder 7 and the fuel injection nozzle located approximately coaxially within the inner cylinder 7 forming a primary air jet port. It mixes with the fuel sprayed from step 2 and burns in the absence of air. In this case, no swirling force is applied to the primary air. This has the effect of a flame-holding plate and stabilizes the flame. On the other hand, the secondary air _A2 is separated from the primary air _A1 , passes through the secondary air passage 11, is given a swirling force by the secondary air swirling adjustment vane 10, is blown out into the furnace, and is mixed with the primary air and combusted. It envelops the flame that is in the air, stabilizes the flame and burns with a lack of air as a whole, and the flame temperature is low, increasing the low NOx effect.

The flame is then surrounded by tertiary air A ₃ whose air volume and rotation angle are adjusted by the air register 4 and supplied through the burner throat 1, and the fuel combustion gas and mixed fuel are completely burned out. Furthermore, by lowering the speed of the primary air _A1 , it can be made to act as a flame stabilizer, and by adjusting the degree of rotation of the secondary air _A2 , the flame can be stabilized.

In this burner device, the total amount of primary air and secondary air can be adjusted by adjusting the opening area of the air port 9 with the damper 5 connected to the handle 5a outside the burner device, so the flame temperature depends on the amount of oil supplied. Even when NOx fluctuates, it can respond correctly and keep it at a low level, making it possible to reduce NOx in exhaust gas. The opening area can be known from outside the windbox by a scale carved on the handle 5a.

Further, the amount of primary air can be adjusted by adjusting the distance between the end of the damper 6 and the end of the inner cylinder 7, that is, the width of the passage, using a primary air amount adjustment damper 6 connected to a handle 6a that can be operated independently.

The secondary air swirl adjustment vane 10 can be rotated to change the secondary air swirl speed using the handle 10a. By providing a bevel gear mechanism at the inner end of the handle 10a, a plurality of blades can be rotated simultaneously and accurately.

By implementing this idea, the amounts of A ₁ and A ₂ of the divided combustion air can be controlled simultaneously, and furthermore, A ₁ and A ₂ can be controlled independently, so that A does not have swirling properties. This means that the fuel injected from the fuel injection nozzle (burner) 2 can have the effect of a flame-holding plate.

Simultaneous control of the total amount of A ₁ and A ₂ also facilitates control to maintain the flame temperature at a low level and achieve low NOx exhaust gas even when the amount of fuel supplied changes in response to load fluctuations.

In addition, the amount of air can be controlled from outside the wall of the wind box of the burner device, making it particularly suitable for large-capacity burners without a pre-combustion chamber, and even existing devices can achieve the low NOx goal with only some modification. It has the following effects.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of a burner device schematically showing an embodiment of this invention. 1... Burner throat, 2... Fuel injection nozzle (burner), 3... Air wind box, 4... Air register, 5... Damper, 6... Primary air adjustment damper,
7...Inner cylinder, 8...Outer cylinder, 9...Air port, 10...
...Secondary air swirl adjustment vane.

Claims (1)

[Claims for Utility Model Registration] 1. A burner is inserted into an air box, and a primary air outlet, a secondary air outlet, and a tertiary air outlet are provided surrounding the burner inside the furnace, in which the above three air outlets are provided. An inner cylinder 7 that surrounds the burner 2 has an air outlet.
And, the outer cylinder 8 and burner throat 1 surrounding this inner cylinder
and a damper 5 for controlling the supply of the total amount of primary and secondary air supplied from an air port 9 provided in the outer cylinder, and a primary air control damper 6 for controlling the primary air and swirling of the secondary air. This burner device is provided with a secondary air swirl adjustment vane 10 for controlling the speed, and an air register 4 for adjusting the tertiary air supply amount in the air box. 2. Utility Model Registration The burner device according to claim 1, in which the air register 4 is an air register that adjusts the flow of supplied air.