JPS596325B2 - gas burner - Google Patents

Description

[Detailed description of the invention] This invention relates to a gas burner.

Currently, it is desired to reduce NOx contained in exhaust gas from gas burners in order to prevent pollution.

Methods for reducing NOx contained in exhaust gas include the exhaust gas recirculation method and the two-stage combustion method, which perform combustion slowly and lower the combustion temperature to reduce NOx.
This suppresses the formation of

In other words, the exhaust gas recirculation method mixes a portion of the exhaust gas into the combustion air and causes oxygen-deficient combustion in the burner section, which lowers the oxygen partial pressure and causes slow combustion, thereby lowering the combustion temperature. This is a method of suppressing the generation of NOx.

In addition, in the two-stage combustion method, combustion is performed by supplying a smaller amount of air than the theoretical air amount in the first stage burner section, and the insufficient amount of air is supplied in the downstream part for complete combustion, thereby reducing the combustion temperature. This is a method to suppress the generation of NOx by lowering the amount of NOx.

However, the conventional gas burner used in this method has a flame baton or a solid convergent shape, so
That is, since the flame gathers in the center of the burner throat, the combustion temperature becomes high, and the combustion gas stays in the high temperature region for a long time, so there is a problem that NOx is likely to be generated.

This invention was made to solve the above-mentioned problems, and an object thereof is to provide a gas burner that generates less NOx.

In order to achieve this purpose, in this invention, the shape of the premixed gas fuel injection hole is made into a conical ring shape that spreads inside the furnace,
A swirl vane is provided inside the premixed gas fuel injection hole, and a rectifying block having a conical surface converging toward the inside of the furnace is provided inside the premixed gas fuel injection hole so as to protrude toward the inside of the furnace.

FIG. 1 is a sectional view showing a gas burner according to the present invention.

In the figure, 1 is a furnace wall, 2 is a premixed gas fuel injection hole provided at the bottom of a cup-shaped recess 1a of the furnace wall 1, and the injection hole 2 has a conical ring shape that widens toward the inside 3 of the furnace.

Reference numeral 4 denotes a swirling vane fixed within the nozzle 2, 5 a rectifying block provided inside the nozzle 2, and the rectifying block 5 having a curved surface protruding toward the inside of the furnace 3, for example, the inside of the furnace 3. It has a conical surface 5a.

6 is a premixing chamber connected to the jet hole 2, 7 is a fuel manifold connected to the premixing chamber 6, 8 is a wind box connected to the premixing chamber 6, and 9 is a combustion chamber provided in the wind box 8. The damper 9 is an air adjustment damper and is automatically controlled according to the amount of fuel supplied.

With this configuration, when combustion air is supplied to the wind box 8 and gas fuel is supplied to the manifold 1, the combustion air and gas fuel are mixed in the premixing chamber 6, and this premixed gas The fuel is spouted from the nozzle hole 2 while being swirled by the swirling vane 4 .

Since the injection hole 2 has a conical ring shape, the premixed gas fuel ejected from the injection hole 2 spreads radially and burns, reducing the internal pressure of the flame. A recirculating stream 10 is created.

For this reason, combustion gas having a low temperature and a low oxygen partial pressure is diffused inside the frame, so a region with a low oxygen concentration is not formed inside the frame, and concentrated combustion is performed.

That is, on the outside of the frame, a region with a high oxygen concentration is formed, so there is no risk of misfire, and on the inside of the flame, a region with a low oxygen concentration is formed, which allows slow combustion to occur, reducing NOx. , is reduced.

Moreover, since the rectifying block 5 is provided inside the jetting hole 2, when the premixed gas fuel is jetted out from the jetting hole 2 at a high speed, an annular low-pressure part is formed at the base of the straightening block 5. The combustion gas flows into the low-pressure part, but in this case, the combustion gas flows along the surface of the rectifying block 5, so the flow is rectified, so the combustion gas flows uniformly and stably in the circumferential direction inside the frame. At the same time, combustion gases diffuse inside the flame at the beginning of combustion.

Furthermore, since the swirling vanes 4 are provided inside the nozzle hole 2, the entire frame rotates, so there is a relative velocity in the circumferential direction between the combustion gas to be diffused into the frame and the frame. quickly diffuses inside.

In this way, the combustion gas diffuses uniformly and stably inside the frame, and quickly in the early stages of combustion.
Since concentration combustion can be reliably performed, NOx can be effectively reduced.

As explained above, in the gas burner according to the present invention, the combustion gas is diffused inside the flame to perform concentrated combustion, and the combustion gas is uniformly and stably distributed inside the frame, and furthermore, in the early stages of combustion. In addition, since the fuel is quickly diffused, concentrated and lean combustion can be reliably performed, so there is no misfire and it is possible to effectively reduce NOx.

Furthermore, this gas burner has a simple structure and can be easily replaced with a gas burner in an existing combustion device.

As described above, the effects of this invention are remarkable.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a gas burner according to the present invention. 1... Furnace wall, 2... Premixed gas fuel injection hole, 4...
・Swirling vane, 5... Rectifier block, 6... Premixing chamber, 1... Fuel manifold, 8... Wind box, 10...
Yamaguchi recirculation flow.

Claims (1)

[Claims] 1 The shape of the premixed gas fuel injection hole is a conical ring that spreads inside the furnace, a swirl vane is provided inside the premixed gas fuel injection hole, and the shape of the premixed gas fuel injection hole is convex inside the furnace. A gas burner characterized in that a rectifying block having a conical surface is provided to protrude inside the furnace.