JPS60105809A - Melting burner - Google Patents

Abstract

PURPOSE:To form a desired flame by a method wherein powder coal and oxygen are mixed and agitated just after an outlet of each of the injection pipes and a flame is formed in the main body of a burner, the flow rate of combustion gas is increased and a complete combustion is always performed. CONSTITUTION:The main body of a burner 2 is provided with a concentric arrangement of a fuel injection pipe 3 for injecting powder coal together with carrier gas and an oxygen injection pipe 4 for injecting combustion oxygen. The proper number of guide blades 5 and 6 which are directed in the same direction are fixed within each of the pipes 3 and 4. Each of the pipes 3 and 4 is opened at a substantial same position in the main body 2 of the burner, lips 7 and 8 are formed in such a way as fine powder coal and flow of oxygen are crossed to each other after their injection and they are mixed and agitated to each other. The main body 2 of the burner is formed as a nozzle 9 having a throat part downstream of the opening of each of the pipes, a flow rate of the combustion gas is increased to promote the mixing operation, thereafter they are expanded and dispersed to perform a complete combustion and to arranged the shape of the flame.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a melting burner, and more particularly to a melting burner that can completely burn a flame-retardant fuel made by pulverizing a solid fuel with low volatility. Regarding.

This is used, for example, in the field of melting bars used to supplement the heat of electric melting in electric furnaces for melting scrap.

[Prior art]

As a pulverized coal bar, there is one disclosed in Japanese Utility Model Application Publication No. 58-10534. This consists of a pulverized coal injection tube that injects pulverized coal together with a carrier gas from the center of the burner body into a crater hole drilled in a burner tile fixed to the furnace wall, and a gas injection tube placed outside the It is equipped with a fuel injection pipe and an air introduction pipe disposed outside the fuel injection pipe, a swirl vane is installed inside the air introduction pipe, and a cylindrical part equal to the diameter of the inner surface of the air introduction pipe is provided at the entrance of the crater part. At the same time, a widening portion is formed toward the inside of the furnace.

In such a pulverized coal burner, after the gas fuel from the gas fuel injection pipe is ignited, the pulverized coal that is injected from the pulverized coal injection pipe together with the carrier gas is swirled by a swirling vane and flows into the air introduction pipe. The flames are agitated and mixed by the secondary air injected by the secondary air and combust, and the flame expands at the spreading part and heats the inside of the furnace. However, since the pulverized coal injection pipe is located in the center of the burner body and has no swirl vanes inside, the pulverized coal injection direction is constant and its disturbance is caused only by secondary air at the crater. It is not enough just to be done.

As a result, unless the diameter of the pulverized coal injection pipe is determined in consideration of the amount of pulverized coal to be injected and the amount of carrier gas, there is a problem in that it is not easy to achieve complete combustion of pulverized coal.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems.
The purpose of this is to enable mixing and stirring of pulverized coal and oxygen immediately after the exit of each injection pipe, increase the flow rate of the combustion gas after the flame grows within the burner body, and achieve a predetermined temperature that always ensures complete combustion at the tip of the burner. Provide a pair of 8/8 fire bars that can form flames.

[Structure of the invention]

The configuration of the present invention will be explained below with reference to FIG.

(i) A fuel injection pipe 3 for injecting pulverized coal accompanied by a carrier gas and an oxygen injection pipe 4 for injecting oxygen for combustion are arranged in a concentric ring shape within the burner body 2, and each injection pipe 3 Guide vanes 5 deflected in the same direction within .4
．． 6 is interposed.

(11) At the outlets 3a, 4a of both injection pipes, which open at substantially the same location in the axial direction within the burner body 2, lips 7.8 are formed which are inclined radially outwardly and inwardly, respectively.

(iii) A pinched and widening nozzle 9 is formed in the burner body 2 from the outlet portions of both injection pipes 3 and 4 to the tip of the burner.

(iv) Inside the fuel injection pipe 3, there is a primary air delivery pipe 3.
and an ignition fuel delivery pipe 14 for injecting ignition fuel are installed concentrically.

[For production]

Pulverized coal in a swirling flow state and oxygen for combustion are agitated and mixed immediately after the exit of the injection pipe, and after increasing the flow rate of the combustion gas in the nozzle where it is caught and spread, a predetermined flame is formed and the combustion gas is completely combusted. It is designed to eject from the tip.

〔Example〕

Hereinafter, the present invention will be explained in detail based on examples thereof.

1 and 2 are sectional views of a /8 burner 1, not showing the I embodiment. In the figure, 2 is the burner body, into which the fuel injection pipe 3 injects pulverized coal together with carrier gas.
Oxygen injection pipes 4 for injecting oxygen for combustion are arranged in a double concentric ring shape. Respective injection tubes 3 and 4
Inside, an appropriate number of guide blades 5. are deflected in the same direction.
6 is fixed so that a swirl is imparted to the flow of the small amount of charcoal and oxygen accompanying the charcoal gas as it flows past. The openings of the injection pipes 3 and 4 are located at almost the same position in the axial direction of the burner body 2, and the openings are located at the outlet 3a of the fuel injection pipe 3 installed inward from the oxygen injection pipe 4.
The burner body 2 is formed with a radially outwardly inclined lip 7, and the outlet 4a of the oxygen injection tube 4 is formed with a radially inwardly inclined lip 8 of the burner body 2. The pulverized coal and oxygen injected from the respective outlets by these lips 7 and 8 form intersecting flows immediately after the outlets, so that the two are mixed and disturbed within the burner body 2. A nozzle 9 is formed downstream of these outlets 3a and 4a, and is a pinch-spreading nozzle that narrows toward the tip of the burner body 2 and gradually widens through a cylindrical portion 9b having a constant diameter. In this sandwiched portion 9a, the flow rate of the combustion gas of the pulverized coal that starts smoking while being mixed with oxygen is increased, and the mixing with oxygen and stirring are promoted during this time. In the cylindrical part 9b, the flame is arranged to have a constant width, and in the widening part 9C, the flame expands and diffuses, reducing the combustion gas flow velocity, achieving complete combustion and regulating the shape of the flame. ing. Reference numeral 10 denotes a cooling pipe through which cooling water for cooling the burner body 2 flows back, and an inverted portion 10a of the cooling water is formed in the bar tip 6114 portion 2a that forms the above-mentioned pinched and expanded nozzle 9 inward. . The burner tip 2a is removable at a threaded portion 11.12 carved in a stepped portion formed in the outer cylinder 2A of the burner body 2 and the oxygen injection pipe 4, and can be used to change the shape of the flame or If the tip of the burner is burnt out, it can be replaced. In addition,
Inside the fuel injection pipe 3, a primary air delivery pipe 13 and an ignition fuel delivery pipe 14 for injecting ignition fuel such as kerosene are installed concentrically. Ignition of this kerosene or the like is easily performed by a known method. Incidentally, there is no problem even if the internal and external arrangement of the fuel injection pipe 3 and the oxygen injection pipe 4 is reversed. By forming the pinched portion 15, when the fluid passes through the injection pipe, the flow is once constricted and then expands at the lip 7, which prevents mixing with the flow from other injection pipes and its flow. There is an advantage that diffusion is further promoted by -JW.

According to the embodiment with such a configuration, pulverized coal can be completely combusted in the following manner.

First, air is injected from the primary air delivery pipe 13 and kerosene is injected from the ignition fuel delivery pipe 14, and ignited by an ignition device (not shown). The flame gets stuck and spreads nozzle 9
Once formed inside, oxygen is injected from the oxygen injection pipe 4 and pulverized coal is injected from the fuel injection pipe 3 together with the gear rear gas.

When the temperature is raised by the combustion of kerosene, the pulverized coal begins to burn due to the injected oxygen. When ignition of pulverized coal is confirmed, the supply of kerosene and primary air is stopped. While the pulverized coal flows through the injection pipe 3, it is swirled by the guide vanes 5, accelerated by the pinched portion 15, expanded at the lip 7, and the pulverized coal spreads evenly and swirls until it reaches the outlet 3.
It spreads out from a and is injected into the nozzle 9. On the other hand, while flowing through the injection pipe 4, the oxygen is swirled by the guide vane 6, and at the lip 8 and the pinched part 9a of the pinched and widened nozzle 9, the oxygen is swirled from the outlet 4a and diagonally toward the center of the bar body 2. is injected into.

As a result, the pulverized coal diffusion jet flow and the oxygen jet flow intersect to mix and stir the two.

Moreover, the mixed flow is accelerated within the pinched part 9a of the pinched and spread nozzle 9, the flame is adjusted to a constant width in the cylindrical part 9b with a constant cross section, and the flame expands and diffuses in the spread part 9C, reducing the combustion gas flow velocity. , complete combustion occurs and the shape of the flame is adjusted. In addition, if the state of the flame is to be changed, the burner tip 2a may be removed by the threaded portion 11, 12 and replaced with another one having a different angle or length. When the fuel injection pipe and the oxygen injection pipe are reversed, the oxygen flow behaves like swirling, pinching and spreading within the injection pipe, and these flows are mixed with the pulverized coal flow at the injection pipe opening, and then pinching and spreading at the nozzle 9. The same behavior as described above occurs within. In these behaviors, the swirling flow given in each injection pipe is in the same direction, and the circumferential flow velocity within the pinched part 9a of the pinched-spreading nozzle 9 is maintained without being mutually inhibited, thereby promoting combustion. Ru. Therefore, such a bar can completely burn flame-retardant pulverized coal with low fuel cost, and can be used as a melting source to complement electric melting in an electric furnace for melting scrap, improving its calorific value and production. It is possible to reduce costs. Note that this melting burner is inserted through the outer wall of the electric furnace in which three vertical electrode rods are installed, and each electrode rod is arranged in a triangular planar arrangement where the heat of melting is difficult to reach. The burner tip is installed so that the flame reaches the upper surface of the scrap at an intermediate position. Therefore, when the temperature inside the electric furnace is around 800°C or higher, pulverized coal is ignited by the atmosphere, but
If such a temperature has not been reached, combustion of the pulverized coal can be started using two series of ignition fuel and/or primary air therefor.

〔Effect of the invention〕

As described in detail in the above embodiments, the present invention provides a fuel injection pipe for injecting pulverized coal together with a carrier gas and an oxygen injection pipe for injecting oxygen for combustion, which are arranged in a concentric ring shape within the burner main body. At the same time, guide vanes deflected in the same direction were interposed in each injection pipe, and a lip was formed at the outlet of each injection pipe that was inclined inward or outward in the radial direction of the burner, resulting in a swirling flow. fuel and oxygen can be efficiently diffused and mixed. Since a nostle is formed that spreads out from the outlet of the injection pipe, complete combustion and desired flame formation are possible. Therefore, it is possible to improve combustion heat and reduce fuel cost, and it is possible to improve scrap melting performance and fuel efficiency in an electric furnace.

The pulverized coal can be ignited even when the temperature inside the electric furnace is low because of the air from the primary air delivery pipe installed concentrically inside the fuel injection pipe and the ignition fuel from the ignition fuel delivery pipe. The ignition becomes extremely easy, and the occurrence of burner trouble during melting can be suppressed or avoided.

[Brief explanation of the drawing]

The first column is a cross-sectional view of a melting chamber according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line -■ in FIG. 1- Melting burner, 2- Nose body, 3° 4- injection pipe, 3a + 4”- 1.5.6-kite vane, 7.
8=-lip, 9-Pinched spreading nostle, 13-Next air delivery L, 14-Ignition fuel delivery pipe, 15-Pented portion Patent applicant Godo Steel Co., Ltd.

Claims (2)

[Claims] (1) A fuel injection pipe that injects pulverized coal accompanied by a carrier gas and an oxygen injection pipe that injects oxygen for combustion are arranged in a concentric ring shape within the burner body, and are arranged in the same direction within each injection pipe. radially outwardly and inwardly inclined lips are formed at the outlets of the two injection tubes which open at substantially the same location in the axial direction within the bar main body, with guide vanes deflected in a direction interposed therebetween; A pinched and widening nozzle is formed in the burner body from the outlet portion of both injection pipes to the bar nozzle uiii, and a primary air delivery pipe and an ignition fuel for injecting ignition fuel are formed inwardly of the injection pipes. The fuel and combustion oxygen in a swirling flow state are agitated and mixed immediately after the outlet of the injection pipe, and a predetermined flame is formed after increasing the flow rate of combustion gas in the nozzle. A dissolving bar characterized by being able to dissolve. (2) The inner injection pipe of the fuel injection pipe and the oxygen injection pipe has a sandwiched portion formed between its lip and the guide blade.
Burner for melting as described in section.