JPS6335227Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Field of Industrial Application) The present invention relates to a burner for burning low-calorie gas such as blast furnace gas, which stably burns low-calorie gas such as blast furnace gas regardless of the temperature inside the combustion chamber and without the need for a pilot burner after ignition. It is something. (Prior art and its problems) Gas burners generally include diffusion combustion type gas burners, which eject combustion gas and air separately and burn them by diffusion mixing, and gas burners, which mix combustion gas and air or oxygen gas in advance before combustion. It is broadly divided into premix combustion type gas burners and premix combustion type gas burners, which perform combustion in different ways.In industrial furnaces, the former diffusion combustion type gas burners are often used. Among these diffusion combustion type gas burners, high swirl flow burners that give strong swirl to combustion air to improve the mixing properties of the air and fuel gas and increase combustion efficiency are attracting attention. However, in the case of the conventional high swirl flow burner described above, a mixture of high calorie gas such as coke oven gas or low calorie gas such as blast furnace gas with high calorie gas is used as fuel gas. Normally, when only low-calorie gas is used as the sole fuel gas, the amount of air required to burn a unit amount of fuel decreases, so the flame stabilizing effect due to swirling flow decreases. Mixing with atmospheric gas results in lean combustion, lowering the flame temperature, making stable combustion impossible and reducing the combustible amount, making it impractical. In addition, there are burners for burning only low-calorie gas other than the burners mentioned above, which are intended for hot air generators, etc., but these burn by slowing down the flow velocity of air and fuel gas to slow the mixing of the two. If the main dimensions of the burner are large relative to the combustion capacity and the temperature inside the heating furnace is low, there is a problem that the flame becomes unstable.
In order to achieve as stable combustion as possible, there was no other option than to use a pilot burner at all times. (Purpose of the invention) The present invention was made in view of the above-mentioned problems, and consists of a flame section in which low-calorie gas at room temperature is separately introduced into two stages and has regions with different mixing ratios with combustion air. The purpose of the present invention is to provide a low-calorie gas combustion burner with a compact design that enables stable combustion even in a cold furnace without requiring a pilot burner after ignition. It is something to do. (Structure of the invention) In other words, the low-calorie gas combustion burner of the invention is provided with a sight hole in the center of the burner body, the tip of which faces into the burner tile, and a swirl vane in the passage around the outer periphery of the sight hole. a secondary fuel injection pipe whose tip is slightly protruding from the sight hole; a primary fuel injection pipe whose tip is provided with a baffle plate and whose tip is positioned rearward from the burner tile; and a passageway. Air introduction pipes each having a swirl vane therein and having a tip thereof located on the rear surface of the burner tile are successively arranged concentrically, and furthermore, the inner circumference of the tip of the secondary fuel injection pipe and the outer circumference of the tip of the sight hole are arranged concentrically. An annular partition plate is fixed to the inner wall of the injection pipe so that the tip thereof is located behind the tip of the secondary fuel injection pipe, and a predetermined portion of the secondary fuel injection pipe is located in front of the position where the partition plate is fixed. A plurality of openings are formed at predetermined intervals in the circumferential direction. (Example) The low calorie gas combustion burner of the present invention will be described in detail below based on an example shown in the drawings. Reference numeral 1 in the figure shows a burner for burning low-calorie gas according to the present invention, and the burner 1 is configured to supply low-calorie gas such as blast furnace gas to two stages individually, so that it can be mixed at different mixing ratios with combustion air. The fuel gas is ejected in multiple layers and is combusted to form a flame section consisting of three regions. Reference numeral 2 denotes a sight hole located at the center of the main body of the burner 1, and the tip of the sight hole 2 slightly faces into the burner tile 3 constituting the combustion area. Further, reference numeral 4 denotes a secondary fuel injection pipe for supplying low-calorie gas that is provided concentrically around the outer periphery of the sight hole 2, and the tip of the secondary fuel injection pipe 4 is located inside the burner tile 3 at the site. It is arranged so as to protrude slightly from the hole 2 (approximately 1/5 of the length of the burner tile 3), and the fuel passage in the injection pipe 4 provides a swirling flow to the circulating gas and supplies it into the burner tile 3. A swirling vane 5 is provided to suit the purpose. Furthermore, 6 is a primary fuel injection pipe for supplying low-calorie gas that is provided concentrically around the outer periphery of the secondary fuel injection pipe 4, and the tip of the primary fuel injection pipe 6 is connected to the burner tile 3. A rectifier plate 7 as shown in FIG. 2 is provided at the tip of the injection pipe 4 and is located further rearward. Furthermore, 8 is an air introduction pipe for supplying combustion air that is provided concentrically around the outer periphery of the primary fuel injection pipe 6, and the tip of the air introduction pipe 8 is connected to the rear surface of the burner tile 3. located at
In addition, a swirling vane 9 that gives a swirling flow to the combustion air is provided in the air flow path in the introduction pipe 8, so that the low calorie gas supplied from the primary fuel injection pipe 6 and the combustion air are mixed as much as possible. This ensures good mixing. Further, 10 is an annular partition plate provided between the inner periphery of the tip of the secondary fuel injection pipe 4 and the outer periphery of the tip of the sight hole 2, and the partition plate 10 is, as shown in FIG. is fixed to the inner wall of the secondary fuel injection pipe 4 so that it is located behind the tip of the secondary fuel injection pipe 4 and in front of the tip of the sight hole 2, and a constriction part is provided in the secondary fuel injection pipe 4. It is designed to allow the formation of Incidentally, reference numeral 11 denotes a plurality of openings formed near the tip of the secondary fuel injection pipe 4 at predetermined intervals in the circumferential direction. (Function of the invention) The low-calorie gas combustion burner of the invention is constructed as shown in the above embodiment, and when using it, as shown in FIG. The low calorie gas supplied from the next fuel injection pipe 4 burns independently to form the flame core a of the flame,

[Table] Table 2 shows the amount of CO and _O2 in the exhaust gas when low-calorie gas is burned under the following combustion conditions using a burner for burning low-calorie gas in this invention and a conventional burner for burning low-calorie gas.
The concentration is shown. <Combustion conditions> (1) Ignite the burner and burn until the temperature inside the furnace reaches 800°C or higher. (Combustion amount is 80%) (2) Keep the flow rate of low-calorie gas fuel constant and reduce the amount of combustion air, measuring the exhaust gas concentration at each stage at the end of the furnace.

[Table] As is clear from Table 2, the burner of the present invention enables stable combustion with less combustion air than conventional burners, and also reduces the amount of CO generated.
It can be seen that this is much less than before. (Effects of the invention) As described above, the low-calorie gas combustion burner of the present invention separates and supplies low-calorie gas at room temperature in two stages to form a flame section having three regions with different air mixing ratios. This reduces the pressure drop in the burner, and after ignition, it is possible to achieve stable combustion without the need for a pilot burner. Moreover, it can be designed compactly, eliminating the problems of the conventional method. It is a useful thing to gain.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention;
FIG. 2 is a sectional view taken along the line AA in FIG. 1, and FIG. 3 is a partially enlarged sectional view showing an embodiment of the present invention. 1 is a low-calorie gas combustion burner, 2 is a sight hole, 3 is a burner tile, 4 is a secondary fuel injection pipe, 5 and 9 are swirl vanes, 6 is a primary fuel injection pipe, 7
is a rectifying plate, 8 is an air introduction pipe, 10 is an annular partition plate,
11 is an opening.

Claims (1)

[Scope of utility model registration request] At the center of the burner body, there is provided a sight hole whose tip faces into the burner tile, and at the outer periphery of the sight hole, a swirl vane is provided in the passage so that its tip faces out in a slightly protruding shape from the sight hole.
a secondary fuel injection pipe, a primary fuel injection pipe having a rectifying plate at the tip and having the tip located behind the burner tile; and a swirl vane provided in the passage and having the tip positioned at the rear of the burner tile. The air introduction pipes are sequentially arranged concentrically, and the tips are positioned rearward from the tips of the secondary fuel injection pipes between the inner periphery of the tips of the secondary fuel injection pipes and the outer periphery of the tips of the sight holes. An annular partition plate is fixed to the inner wall of the injection pipe, and a plurality of openings are bored at predetermined intervals in the circumferential direction near the tip of the secondary fuel injection pipe. A low calorie gas combustion burner characterized by: