JPH02279909A - For gas fuel of low calorific value - Google Patents

Abstract

PURPOSE:To obtain a low calorific value gas fuel burner by providing guide vanes for turning fuel gas in a specific direction to the lateral direction of an inner cylinder, a circular air manifold for holding a burning tube, and guide vanes parallel to the longitudinal direction of the burning tube, and regulating flame length according to the position of the vanes. CONSTITUTION:Blast furnace gas is supplied into an inner cylinder 2 through a blast furnace gas supply tube 1, and guided to fuel gas guide vanes 3. The gas is turned in a direction of 30 to 45 deg. to the longitudinal direction of the cylinder 2. The gas is advanced in a burning tube 4 while turning and burning air is supplied to a circular air manifold 6 for enclosing the tube 4 provided outside the tube 4 though holes 7 for blowing while turning in the same direction as the turning of the gas, mixed with the air and the gas in the tube 4 and turned in the same direction, thereby obtaining stable flame with low relative speed.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a burner for low-calorie gas fuel such as blast furnace gas, which has good flame-holding function.

[Prior art] Generally, gas burners include diffusion combustion type gas burners, which eject fuel gas and air separately and burn them by diffusing and mixing them, and pre-burners, which mix fuel gas and air in advance before combustion. Although they are broadly classified into mixed combustion type gas burners, diffusion combustion type gas burners are often used in large industrial furnaces because of their low risk of explosion. Among these diffusion combustion type gas burners, high swirl flow gas burners are attracting attention because they give combustion air a strong swirl to improve the mixing of the air and fuel gas, thereby increasing combustion efficiency. However, the conventional high swirl flow gas burner described above uses a mixture of high calorie gas such as coke oven gas or low calorie gas such as blast furnace gas as fuel gas. Normally, when only low-calorie gas is used as a fuel gas, the amount of air required to burn a unit amount of fuel decreases, the flame stabilizing effect due to swirling flow decreases, and the flame stabilization effect due to swirling flow decreases. Furthermore, the fuel gas becomes diluted, the flame temperature decreases, and stable combustion becomes impossible.
This was not practical as a banner for low-calorie gas.

In addition, burners for exclusive use of low-calorie gas other than the above-mentioned burners include those used in hot-blast ovens, etc., which slow down the flow rate of air and fuel gas to slow the mixing of the two for combustion. However, if the size of the burner becomes large and the temperature inside the furnace is low, there is a problem that the flame becomes unstable.

Furthermore, high swirl flow gas burners have the problem that it is difficult to control the shape of the flame, and are limited to short flames and for local heating, making it difficult to apply them to applications such as boilers.

[Problems to be solved by the invention] However, in the conventional low-calorie gas-only burners mentioned above, the low flow rate burner has a large burner size relative to the combustion capacity, and the high swirl flow gas burner has a large flame size. There are problems such as the shape is limited to a short flame, and the flame is unstable. This idea was made in view of the above circumstances, and is a low-calorie gas fuel burner that can provide a stable flame, control the length of the flame, and has a compact burner size relative to the combustion capacity. The purpose is to provide.

[Means for Solving the Problems] The banner for low calorie gas fuel according to this invention has a vertical structure in the inner cylinder in which fuel gas is supplied from the inner cylinder and combustion air is supplied from the outside. 30 for the direction
A guide vane that swirls the fuel gas in the direction of 45 degrees is provided in the inner cylinder, and combustion air is blown from the outside into the fuel gas swirling in the combustion tube connected to the guide vane while swirling in the same direction. An annular air manifold enclosing a combustion tube having holes is provided, and a guide parallel to the longitudinal direction of the combustion tube is provided at a downstream position in the combustion tube to direct a mixed gas of fuel gas and combustion air. A vane is provided;
It is characterized in that the flame length is adjusted by the position of the guide vane.

[Function] Since this device is constructed as described above, even when only low-calorie gas fuel is used, a stable flame can be obtained because the relative velocity between the fuel gas and the combustion air is low, and the fuel gas The length of the flame can be controlled because the position of the guide vane, which allows the mixture of fuel gas and combustion air to flow in a straight line, is variable, and since the fuel gas and combustion air are swirling, the flame length can be controlled. The dimensions of the burner are compact.

[Example] An example of this invention will be described below with reference to the drawings. 1st
The figure is an explanatory diagram showing a schematic vertical cross section of the low calorie gas fuel burner of this invention. In the figure, blast furnace gas is supplied to an inner cylinder 2 through a blast furnace gas supply pipe 1 and guided to a fuel gas guide vane 3. The blast furnace gas is thereby transferred to the inner cylinder 2.
It is rotated in a direction of 30° to 45° with respect to the longitudinal direction of the machine. Outside this angular range, mixing properties deteriorate or the swirling flow is disturbed due to fluid collisions, making it difficult to achieve stable combustion. FIG. 2 shows a concave cross section of the guide vane 3 taken along the line AA'. The blast furnace gas moves through the combustion tube 4 while swirling. Combustion air is supplied through an air supply pipe 5 to an annular air manifold 6 provided outside the combustion pipe 4 and enclosing the combustion pipe 4 .

Combustion air is supplied to the combustion tube 4 through the blow-in hole 7 while being swirled in the same direction as the blast furnace gas.

Combustion air and blast furnace gas mix in the combustion tube 4 while swirling. Fig. 3 shows the above-mentioned combustion air blowing hole 7.
The figure shows a B-B cross section where the combustion air and blast furnace gas can be seen. Since the combustion air and blast furnace gas rotate in the same direction, the relative speed is low and a stable flame can be obtained. The mixture of combustion air and blast furnace gas is 4, the mixed gas enters a guide vane 8 which turns the mixed gas into a straight flow. FIG.

FIG. 5 shows the relationship between the position of the guide vane 8, which is a current plate, and the length of the flame. As is clear from the figure, it was found that by moving the position of the guide vane 8, which is a current plate, to the upstream side, the flame length was shortened.

[Effects of the invention] As described above, since this invention is configured, even when only a low-calorie gas fuel burner is burned, a stable flame can be obtained, and the length of the flame can be controlled. Since the size of the combustion capacity is about 100 yen or more, burners such as power generation boilers can be operated using only low-calorie gas fuel such as blast furnace gas even during low fire.

[Brief explanation of drawings]

Fig. 1 is a vertical plan view showing an overview of the burner of this invention, Fig. 2 is a sectional view taken along line AA', Fig. 3 is a sectional view taken along line 13-B, and Fig. 4 is a sectional view taken along line 13-B.
The figure is a sectional view taken along the line C-C, and FIG. 5 is an explanatory diagram showing a situation where the flame length becomes shorter when the position of the gas mixture guide is moved to the upstream side. 1... Blast furnace gas supply pipe, 2 - Inner cylinder, 3 Kite vane for blast furnace gas, 4 - Combustion pipe, 5 - Air supply pipe, 6 Air manifold, hole for blowing air, Guide vane for mixed gas

Claims (1)

[Claims] In a burner to which fuel gas is supplied from the inner cylinder and combustion air is supplied from the outside thereof, a guide vane is provided in the inner cylinder to rotate the fuel gas in a direction of 30° to 45° with respect to the longitudinal direction of the inner cylinder. An annular air manifold is installed to enclose the combustion tube and has a hole for blowing combustion air from outside into the swirling fuel gas in the combustion tube while swirling it in the same direction. A guide vane parallel to the longitudinal direction of the combustion tube is provided at a downstream position of the combustion tube to cause a mixed gas of fuel gas and combustion air to flow in a straight line, and the flame length is adjusted by the position of the guide vane. A burner for low calorie gas fuel.