WO2011024814A1

WO2011024814A1 - Gas jet device

Info

Publication number: WO2011024814A1
Application number: PCT/JP2010/064301
Authority: WO
Inventors: 照祥平岡
Original assignee: 株式会社Istc
Priority date: 2009-08-28
Filing date: 2010-08-24
Publication date: 2011-03-03
Also published as: TW201114918A

Abstract

Disclosed is a gas jet device (1) that jets a mixed gas containing fuel gas and oxygen gas, and that is provided with: a Laval nozzle (2), within which oxygen gas flows and a fuel gas supply part (24) is formed on the inner peripheral surface, and wherein fuel gas is supplied from the fuel gas supply part (24) to the interior; and a fuel gas supply tube (3) that extends in the axial direction within the Laval nozzle (2), and that supplies fuel gas within the Laval nozzle (2).

Description

Gas injection device

The present invention relates to a gas injection device that injects a mixed gas containing fuel gas and oxygen gas.

Conventionally, various methods for iron making have been proposed. For example, a method using iron ore as a raw material includes a blast furnace-converter method, and a method using scrap iron such as scrap as a raw material. There were an electric furnace method and a cold iron source melting method (for example, Patent Documents 1 to 3).

In the blast furnace-converter method, iron oxides such as iron ore are used as raw materials, and this is reduced by coke, which is a reducing agent, to obtain molten iron (hot metal) in a carbon saturated state. The coke is also used as thermal energy by burning with high-temperature air. Since the molten iron obtained by this blast furnace method contains carbon and is brittle, the carbon in the molten iron is removed by blowing a high-concentration oxygen gas into the molten iron using a converter. In the converter process, the high-concentration oxygen gas blown into the molten iron also has a role of heating the molten iron temperature to a desired temperature by burning carbon in the molten iron.

Also, in the electric furnace method, scrap iron is put into the furnace body and the energized graphite electrode is lowered toward the scrap iron. The graphite electrode forms an arc plasma with the furnace bottom electrode installed at the bottom of the furnace body, and when the graphite electrode descends, a boring hole is formed while melting scrap iron by the arc plasma. And if a graphite electrode descend | falls to the bottom part vicinity of a furnace main body, it will stop in that position, and melt | dissolves surrounding scrap iron by continuing to emit arc plasma.

In the cold iron source melting method, scrap iron, which is an iron source, is housed in the furnace body, pulverized coal is supplied from the bottom of the furnace body, and oxygen is blown from above, thereby burning the pulverized coal and melting the scrap iron. To do.

Japanese Patent Laid-Open No. 6-256022 JP-A-8-157929 Japanese Patent Laid-Open No. 1-283312

However, each of the steel making methods described above has the following problems. First, in the blast furnace-converter method, iron dust is generated when carbon in molten iron is burned with high-purity oxygen gas. This not only causes loss of thermal efficiency and iron yield, but also recovers and recovers dust. There was a problem that processing costs were incurred for use. In addition, the electric furnace method is problematic in that expensive electric power is used as thermal energy, the expensive graphite electrode is consumed, the steel material from which a large amount of nitrogen in the atmosphere can be dissolved in the molten steel is hardened, and the production rate is high. There were problems such as being slower than the blast furnace method. Also, in the cold iron source melting method, CO gas bubbles generated in molten iron are dispersed in the atmosphere and burst on the surface of the molten iron, so that fine molten iron particles are scattered in the atmosphere and so-called bubble burst dust is generated. There was a problem.

In response to the above problems of the respective methods, the present inventors have found that each problem can be solved by injecting a mixed gas. For example, in the blast furnace-converter method, iron dust is generated by decarburization using iron oxide such as iron ore instead of high-purity oxygen gas and supplying heat with a mixed gas of fuel gas and oxygen gas. It has been found that decarburization can be achieved while suppressing carbon dioxide. In addition, in an electric furnace, after forming a bored hole with a graphite electrode, the graphite electrode is extracted, a metal tube burner lance is inserted into the bored hole, and a mixed gas is injected from the burner lance to heat scrap iron, etc. It has been found that the above-mentioned problems can be solved. Also, in the cold iron source melting method, if the mixed gas is blown from above instead of blowing oxygen gas from above, scrap iron can be dissolved by the combustion heat of the mixed gas, so there is no need to burn carbon, As a result, generation of bubble burst dust can be prevented. In addition to these, a step of injecting a mixed gas can be incorporated in various iron making methods.

As described above, it has been found that it is effective to incorporate a step of injecting a mixed gas in various iron making methods. However, it is preferable that the mixed gas is injected in a uniformly mixed state. Then, an object of this invention is to provide the gas injection apparatus which can inject a more uniform mixed gas.

The gas injection device according to the present invention is a gas injection device for injecting a mixed gas containing fuel gas and oxygen gas, wherein the oxygen gas flows inside and a fuel gas supply part is formed on an inner peripheral surface, and the fuel A Laval nozzle that supplies fuel gas from a gas supply unit to the inside, and a fuel gas supply pipe that extends in the axial direction inside the Laval nozzle and supplies the fuel gas into the Laval nozzle.

According to the gas injection device configured as described above, the fuel gas is supplied from the inside of the oxygen gas flowing in the Laval nozzle through the fuel gas supply pipe, and the oxygen gas flowing in the Laval nozzle is formed on the inner peripheral surface of the Laval nozzle. The fuel gas is supplied by the fuel gas supply unit. As described above, since the fuel gas is supplied from both the inside and the outside of the oxygen gas flowing in the Laval nozzle, it is possible to obtain a mixed gas in which the fuel gas and the oxygen gas are sufficiently mixed. Examples of the fuel gas include liquefied petroleum gas (LPG), liquefied natural gas (LNG), butane gas, hydrogen gas, and CO gas.

The gas injection device can take various configurations. For example, the fuel gas supply part is preferably an annular slit formed along the circumferential direction of the inner peripheral surface of the Laval nozzle. In addition, the fuel gas supply unit includes a first fuel gas supply hole row formed of a plurality of fuel gas supply holes formed so as to be arranged at intervals in the circumferential direction of the inner peripheral surface of the Laval nozzle, A second fuel gas supply hole row formed of a plurality of fuel gas supply holes formed on the downstream side of the first fuel gas supply hole row so as to be arranged at intervals in the circumferential direction of the inner peripheral surface of the Laval nozzle; The fuel gas supply holes constituting the second fuel gas supply hole array are formed with fuel gas supply holes between the fuel gas supply holes constituting the first fuel gas supply hole array. It is preferable to adopt a configuration in which it is formed at a position corresponding to a position that is not.

As described above, the fuel gas supply unit is configured to supply the fuel gas so as to seamlessly cover the oxygen gas flowing in the Laval nozzle from the outside, so that in the outer peripheral region of the mixed gas injected from the gas injection device The ratio of the fuel gas can be made larger than the ratio of the fuel gas in the complete combustion ratio. When such a mixed gas collides with the molten iron, the oxygen gas in the mixed gas reacts with the fuel gas in the mixed gas before it reacts with the iron and carbon on the molten iron side, so iron oxide is formed. Or the decarburization reaction by oxygen gas can be prevented more reliably.

The fuel gas supply pipe is preferably configured to supply fuel gas in the radial direction of the Laval nozzle. According to this, the fuel gas can be introduced into the oxygen gas in a direction substantially orthogonal to the flow direction of the oxygen gas, and the fuel gas and the oxygen gas can be mixed more uniformly.

Further, the fuel gas supply pipe can supply fuel gas in the vicinity of the throat portion of the Laval nozzle, or can supply fuel gas downstream or upstream of the throat portion. In particular, by supplying the fuel gas on the upstream side of the diameter-reduced portion of the Laval nozzle, it is possible to generate turbulent flow and mix oxygen gas and fuel gas more uniformly. In this case, the fuel gas supply pipe is configured to have a fuel gas supply pipe main body extending in the Laval nozzle and a plurality of branch pipes extending radially from the fuel gas supply pipe main body, and the fuel gas is passed through each branch pipe. Can be supplied into the Laval nozzle.

Further, it is preferable to further include a first original pressure control means for controlling the original pressure of the oxygen gas and a second original pressure control means for controlling the original pressure of the fuel gas. Thus, by providing each original pressure control means, it is possible to control the ejection speed of the mixed gas composed of the fuel gas and the oxygen gas, and thus to control the combustion position of the mixed gas.

According to the present invention, it is possible to provide a gas injection device capable of injecting a more uniform mixed gas at supersonic speed.

FIG. 1 is a side sectional view of the gas injection device according to the present embodiment. FIG. 2 is a schematic view of the converter according to the present embodiment. FIG. 3 is a side sectional view of a gas injection device according to another embodiment. FIG. 4 is a side sectional view of a gas injection device showing still another embodiment. FIG. 5 is a side cross-sectional view of a gas injection device showing still another embodiment. FIG. 6 is a view of the fuel gas supply pipe of FIG. 5 as viewed from the downstream side, and the description of the Laval nozzle is simplified.

Hereinafter, embodiments of a mixed gas injection device according to the present invention will be described with reference to the drawings. In the following description, the left side of FIGS. 1 and 4 is referred to as upstream and the right side is referred to as downstream, and the horizontal direction of FIG. 1 is referred to as the axial direction of the Laval nozzle.

As shown in FIG. 1, the mixed gas injection device 1 includes a Laval nozzle 2 that accelerates the fluid flowing inside to a supersonic speed, and a fuel gas supply pipe 3 that extends in the Laval nozzle 2 in the axial direction.

The Laval nozzle 2 is formed in a substantially cylindrical shape having a central axis C, and an inner peripheral surface thereof is formed such that the inner diameter is reduced from the upstream toward the downstream and the diameter is increased in the middle. The throat portion 21 is the place where the inner diameter of the boundary portion where the diameter decreases from the reduced diameter is the smallest. Further, the diameter-expanded portion 22 on the downstream side of the throat portion 21 is the diameter-expanded portion 22, and the portion on the upstream side of the throat portion 21 is the diameter-reduced portion 26. Inside the peripheral wall of the Laval nozzle 2, a cooling water passage 23 for flowing cooling water is formed. The cooling water passage 23 is provided with a cylindrical partition wall 231 so that the cooling water flows from the upstream to the downstream inside the peripheral wall and then flows from the downstream to the upstream outside the peripheral wall. Yes. The material of the Laval nozzle 2 is preferably copper or a copper alloy from the viewpoint of preventing the occurrence of sparks. The upstream end of the Laval nozzle 2 is connected to an oxygen gas supply source (not shown) so that oxygen gas flows into the Laval nozzle 2 from upstream to downstream.

Further, the Laval nozzle 2 has a fuel gas supply part 24 for supplying fuel gas into the Laval nozzle 2 on the inner peripheral surface thereof. The fuel gas supply unit 24 is an annular slit formed without a cut along the circumferential direction of the inner peripheral surface of the Laval nozzle 2. Further, the position where the fuel gas supply unit 24 is formed is not particularly limited, and can be formed, for example, in the vicinity of the throat unit 21 or on the downstream side of the throat unit 21. Each fuel gas supply section 24 is connected to a fuel gas supply path 25 extending through the cooling water flow path 23. The fuel gas supply path 25 is connected to a fuel gas supply source (not shown). The gas pressure of the fuel gas supplied from the fuel gas supply source is preferably higher than the gas pressure of the oxygen gas supplied from the oxygen gas supply source described above.

The fuel gas supply pipe 3 is formed in a cylindrical shape whose end face on the downstream side is sealed, and is installed so as to extend in the axial direction within the Laval nozzle 2 with its central axis substantially coincident with the central axis C of the Laval nozzle 2. Has been. The upstream end of the fuel gas supply pipe 3 is directly or indirectly connected to a fuel gas supply source (not shown). The fuel gas supply source may be the same as that connected to the fuel gas supply path 25 or may be different. Further, the downstream end is located in the vicinity of the throat portion 21, and a plurality of fuel gas discharge holes 31 for discharging the fuel gas flowing through the fuel gas supply pipe 3 into the Laval nozzle 2 are formed. The discharge direction of the fuel gas discharged from the fuel gas discharge hole 31 into the Laval nozzle 2 is substantially perpendicular to the radial direction of the Laval nozzle 2, that is, the traveling direction of the oxygen gas.

The plurality of fuel gas discharge holes 31 includes an annular upstream fuel gas discharge hole array 310a formed on the outer peripheral surface of the fuel gas supply pipe 3 so as to be arranged at predetermined intervals along the circumferential direction, and the upstream side A downstream fuel gas discharge hole row 310b formed in the same manner on the downstream side of the fuel gas discharge hole row 310a is configured. Each of the fuel gas discharge hole arrays 310a and 310b has the fuel gas discharge hole 31 of the downstream fuel gas discharge hole array 310b at a position corresponding to the space between the adjacent fuel gas discharge holes 31 of the upstream fuel gas discharge hole array 310a. In order to be formed, the positions are shifted in the circumferential direction. In this way, by forming the fuel gas discharge holes 31 of the upstream fuel gas discharge hole array 310a and the fuel gas discharge holes 31 of the downstream fuel gas discharge hole array 310b at alternate positions, the inside of the Laval nozzle 2 The fuel gas can be evenly supplied from the inside of the oxygen gas flowing through. The fuel gas discharge hole row 310 is not particularly limited to two rows, and may be three or more rows. Further, the shape of each fuel gas discharge hole 31 is not limited to a circle, and can be various shapes such as an ellipse and a slit. The material of the fuel gas supply pipe 3 is preferably stainless steel, copper, copper alloy or the like.

The gas injection apparatus configured as described above can be used in various iron making methods such as a blast furnace-converter method, a gas reduction method, a direct smelting reduction method, an electric furnace method, and a cold iron source melting method. Below, the case where a gas-injection apparatus is used for a converter method as the example is demonstrated.

As shown in FIG. 2, the converter 5 includes a furnace body 4 for containing molten iron and a gas injection device 1 installed above the furnace body 4. The furnace body 4 is formed in a barrel shape, a pear shape, or the like, and is configured to be freely rotatable back and forth. The outer wall of the furnace body 4 is made of steel, and the inner wall is lined with refractory bricks to withstand high heat and impact.

The furnace body 4 configured in this manner is tilted by rotating back and forth, and hot metal containing carbon is injected into the tilted furnace body 4. The carbon content of the molten iron is not particularly limited, but can be 1 to 5% by weight in molten iron, and preferably 3 to 5% by weight. At this time, scrap iron can be supplied to the furnace body 4 together with the hot metal. The supply amount of the hot metal and scrap iron is not particularly limited, and may be determined as appropriate depending on the capacity of the converter to be used. For example, it is preferable that scrap iron is 30 parts by weight or less with respect to 100 parts by weight of hot metal containing carbon. When scrap iron exceeds this range, the necessary amount of heat supply increases, so the refining time is extended and the time balance of the entire process tends to be lost. Accordingly, the amount of scrap iron used may be selected in consideration of the overall economics of the steel manufacturing process and the scrap iron market.

Subsequently, iron oxide as an oxygen source for the decarburization reaction is continuously charged into the furnace body 4 until the carbon content in the molten iron reaches a desired value. The supply rate of this iron oxide is not particularly limited, but since the converter refining time is generally about 10 to 30 minutes, it is preferably about 0.1 to 10 tons / minute, and preferably 2 to 7 tons. / Min is more preferable. The supply time is appropriately determined depending on the supply amount of iron oxide determined by the amount of hot metal and the above-described supply rate. For example, the supply time is 1 to 30 minutes (preferably 10 to 30 minutes, more preferably (10-20 minutes) It is preferable to continuously add iron oxide into the converter. Examples of the iron oxide include iron ore, fine ore pellets, sintered ore, iron dust pellets, and iron dust briquettes.

In parallel with the introduction of iron oxide, the gas injection device 1 injects a mixed gas composed of fuel gas and oxygen gas onto the hot metal. More specifically, the oxygen gas flows into the Laval nozzle 2 of the gas injection device 1 and the fuel gas flows into the fuel gas supply pipe 3 so that the fuel gas is discharged from the fuel gas discharge holes 31 into the Laval nozzle 2. Fuel gas is mixed from the inside of the oxygen gas flowing in the Laval nozzle 2. Still further, the fuel gas is supplied from the fuel gas supply unit 24 into the Laval nozzle 2 by flowing the fuel gas through the fuel gas supply path 25, and the fuel gas is mixed from the outside of the oxygen gas flowing through the Laval nozzle 2. Thus, in order to mix fuel gas from both the inside and the outside of the oxygen gas flowing in the Laval nozzle 2, a sufficiently mixed gas mixture is injected from the gas injection device 1. In addition, as a mixing ratio of fuel gas and oxygen gas, a mixing ratio for complete combustion can be exemplified. The complete combustion mixture ratio varies depending on the type of gas used. For example, when LNG is used as the fuel gas, fuel gas: oxygen gas = 1.2.30, and when LPG is used as the fuel gas. Fuel gas: oxygen gas = 1: 5.12 is preferable. Further, the total amount of fuel gas supplied from each fuel gas supply unit 24 into the Laval nozzle 2 is smaller than the total amount of fuel gas discharged from each discharge hole 31 of the fuel gas supply pipe 3 into the Laval nozzle. However, the present invention is not limited to this, and the total amount of fuel gas from each fuel gas supply unit 24 is increased or the total amount of fuel gas from the fuel gas supply pipe 3 is It is also possible to do the same.

As described above, by injecting the mixed gas from the gas injection device 1 to the hot metal at supersonic speed, a combustion reaction is caused, and the hot metal is heated by this heat of combustion reaction. The heating temperature of the molten iron is not particularly limited, but is usually about 1600 to 1700 ° C. and about 1620 to 1680 ° C. The injection speed of the mixed gas at this time is equal to or higher than the speed of sound, The Mach number is preferably about 1 to 3, and the hot metal can be sufficiently stirred by setting the injection speed to such a value. Also, the hot metal can be agitated by exhaust gas (CO2 gas or H2O gas) generated by high-frequency combustion reaction heat.

By injecting the mixed gas into the molten iron using the gas injection device 1 as described above, for example, when iron ore is charged as iron oxide, the iron ore charged into the furnace body 4 is mixed with the mixed gas in the molten iron. After being rolled up, it floats and floats on the top surface of the molten iron. When this iron ore and carbon dissolved in molten iron come into contact with each other, the carbon is extremely active, so it immediately combines with oxygen held in the iron ore to generate CO gas, and the iron content in the iron ore is reduced. It becomes iron. This reduction reaction occurs on the iron ore surface. In addition, since this reaction is endothermic, the temperature of the CO gas bubbles tends to decrease as the reaction proceeds. Therefore, the behavior of the CO gas bubbles in the decarburization reaction with pure oxygen gas in which the bubbles grow with rapid volume expansion. Will be significantly different.

Even if iron ore having a specific gravity smaller than that of molten iron may be temporarily caught in molten iron, it always floats near the upper surface of the molten iron, so that CO gas bubbles generated by the reduction reaction occurring on the surface of the iron ore are always The bubble burst phenomenon caused by CO gas bubbles generated in the decarburization reaction with pure oxygen gas does not occur from the vicinity of the upper surface of the molten iron into the atmosphere. In addition, the contact surface between the iron ore and the hot metal is cooled by room temperature iron ore, and since the decarburization reaction is an endothermic reaction, a high temperature region called a fire point (2750 ° C., which is the boiling point of iron). (Region exceeding the upper limit) is not formed. Therefore, generation | occurrence | production of the fume dust which iron evaporates can also be prevented.

As mentioned above, although embodiment of this invention was described, this invention is not limited to these, A various change is possible unless it deviates from the meaning of this invention.

For example, as shown in FIG. 3, the downstream end of the fuel gas supply pipe 3 can be conical. By setting it as such a shape, the flow of the mixed gas injected from the Laval nozzle 2 can be made smooth, and it can suppress that the injection speed of mixed gas falls. In addition, it is preferable that the shape in the conical part of this fuel gas supply pipe | tube 3 is a shape symmetrical with the internal peripheral surface of the opposite Laval nozzle 2 from a viewpoint of making the flow of mixed gas smoother.

Further, as shown in FIG. 4, the fuel gas supply unit 24 may be replaced with two rows of fuel gas

supply hole rows

241a and 241b constituted by a plurality of fuel gas supply holes 241 instead of slits. More specifically, the first fuel gas supply hole row 241a formed on the upstream side is constituted by a plurality of fuel gas supply holes 241 formed so as to be arranged at intervals in the circumferential direction of the inner peripheral surface of the Laval nozzle 2. The second fuel gas supply hole row 241b is similarly configured on the downstream side of the first fuel gas supply hole row 241a. The positions corresponding to the positions corresponding to the positions between the fuel gas supply holes 241 constituting the first fuel gas supply hole array 241a, that is, the fuel gas supply holes 241 of the first fuel gas supply hole array 241a are formed. A fuel gas supply hole 241 that constitutes the second fuel gas supply hole row 241b is formed at a position corresponding to the non-existing position. By forming the fuel gas supply holes 241 alternately in this way, the fuel gas can be evenly supplied so as to surround the outside of the oxygen gas flowing in the Laval nozzle 2. In addition, this fuel gas supply hole row | line | column is not restricted to 2 rows, It can also be made into 3 or more rows.

Moreover, in the said embodiment, although the downstream edge part of the gas supply pipe 3 was located in the throat part 21 vicinity, it is not limited to this in particular, For example, the downstream edge part of the gas supply pipe 3 Can be positioned upstream of the diameter-reduced portion 26, thereby generating turbulent flow and more uniformly mixing the fuel gas and the oxygen gas. In this case, the gas supply pipe 3 having the same configuration as that of the above-described embodiment may be simply moved to the upstream side, and various other configurations may be employed. As an example, for example, as shown in FIGS. 5 and 6, the fuel gas supply pipe 3 includes a fuel gas supply pipe main body 32 extending in the axial direction in the Laval nozzle 2, and a radial direction from the outer peripheral surface of the fuel gas supply pipe main body 32. And a plurality of branch pipes 33 extending radially toward. The plurality of branch pipes 33 communicate with the fuel gas supply pipe main body 32, and a slit 321 facing the downstream side is formed so as to supply the fuel gas flowing through the fuel gas supply pipe main body 32 into the Laval nozzle 2. Yes. The structure of the branch pipes 33 is not particularly limited as long as the fuel gas in the fuel gas supply pipe main body 32 can be supplied into the Laval nozzle 2. For example, the slit 321 faces the upstream side. It may be formed or may be formed by a plurality of holes instead of the slits 321.

In addition, the plurality of branch pipes 33 described above are preferably configured in a plurality of stages in the axial direction of the Laval nozzle 2 as a group of branch pipes 33. In the present embodiment, the three branch pipes 3 are arranged on the most downstream side. The three branch pipes 33a constitute a first-stage branch pipe group, the subsequent three branch pipes 33b constitute a second-stage branch pipe group, and the three branches arranged on the most upstream side A third-stage branch pipe group is configured by the pipe 33c. The branch pipes 33 constituting each branch pipe group are arranged at equal intervals, and the branch pipes 33 viewed from the axial direction of the Laval nozzle 2 are arranged at equal intervals so as not to overlap each other. preferable. More specifically, in the case where three branch pipe groups are formed by three branch pipes as described above, first, in each branch pipe group, each branch pipe 33 is connected to the adjacent branch pipe 33 and the central axis C. An angle of 120 degrees is formed at the center. Further, with the first-stage branch pipe group as a reference, the second-stage branch pipe group is rotated around the central axis C by 30 degrees, and the third-stage branch pipe group is rotated around the central axis C. The state is rotated 60 degrees. In this way, all the branch pipes 33 viewed from the axial direction of the Laval nozzle 2 are all arranged at equal intervals. As a result, the fuel gas can be uniformly supplied to the entire region of the oxygen gas flowing in the Laval nozzle 2. it can. Of course, the number of branches and the number of branches are not limited to those described above.

Further, although the Laval nozzle 2 is connected to an oxygen gas supply source, a first source pressure control device can be installed in order to control the source pressure of the oxygen gas. Similarly, a fuel gas supply source is connected to the fuel gas supply pipe 3 and the fuel gas supply path 25. In order to control the original pressure of the fuel gas supply source, a second original pressure control device is used. Can also be installed. By installing the first and second source pressure control devices in this way, it is possible to control the ejection speed of the mixed gas composed of the fuel gas and the oxygen gas, and thus to control the combustion position of the mixed gas. It becomes. For example, at the beginning of the melting period of electric furnace operation, the mixed gas is burned on the side near the nozzle by lowering the original pressure of the mixed gas, and then the mixed gas combustion position, i.e., the original pressure of the mixed gas is increased. Move the flame formation location away from the nozzle to burn the mixed gas near the center of the furnace, and further lower the original pressure of the mixed gas and lower the mixed gas combustion position toward the nozzle again as melting progresses And move. Thus, productivity can be improved by controlling a flame formation place by melt | dissolution time. In addition, it is preferable that the jet speed of mixed gas shall be more than a flame propagation speed.

DESCRIPTION OF SYMBOLS 1 Gas injection apparatus 2 Laval nozzle 21 Throat part 24 Fuel gas supply part 241 Fuel gas supply hole 241a 1st fuel gas supply hole row 241b 2nd fuel gas supply hole row 3 Fuel gas supply pipe 32 Fuel gas supply pipe main body 33 Branch tube

Claims

A gas injection device for injecting a mixed gas containing fuel gas and oxygen gas,
A laval nozzle in which oxygen gas flows inside, a fuel gas supply part is formed on the inner peripheral surface, and fuel gas is supplied to the inside from the fuel gas supply part;
A fuel gas supply pipe extending in the axial direction in the Laval nozzle and supplying fuel gas into the Laval nozzle;
A gas injection device comprising:
The gas injection device according to claim 1, wherein the fuel gas supply unit is an annular slit formed along a circumferential direction of the inner peripheral surface of the Laval nozzle.
The fuel gas supply unit
A first fuel gas supply hole array composed of a plurality of fuel gas supply holes formed so as to be arranged at intervals in the circumferential direction of the inner peripheral surface of the Laval nozzle;
A second fuel gas supply hole comprising a plurality of fuel gas supply holes formed on the downstream side of the first fuel gas supply hole row so as to be arranged at intervals in the circumferential direction of the inner peripheral surface of the Laval nozzle. A column, and
Each fuel gas supply hole constituting the second fuel gas supply hole row corresponds to a position where no fuel gas supply hole is formed between the fuel gas supply holes constituting the first fuel gas supply hole row. The gas injection device according to claim 1, wherein the gas injection device is formed at a position where the gas injection is performed.
The gas injection device according to claim 1, wherein the fuel gas supply pipe supplies fuel gas in a radial direction of the Laval nozzle.
The gas injection device according to claim 1, wherein the fuel gas supply pipe supplies fuel gas in the vicinity of a throat portion of the Laval nozzle.
2. The gas injection device according to claim 1, wherein the fuel gas supply pipe supplies fuel gas upstream of a reduced diameter portion of the Laval nozzle.
The fuel gas supply pipe has a fuel gas supply pipe main body extending in the Laval nozzle, and a plurality of branch pipes extending radially from the fuel gas supply pipe main body, through the branch pipes. The gas injection device according to claim 6, wherein fuel gas is supplied into the Laval nozzle.
First source pressure control means for controlling the source pressure of the oxygen gas;
Second source pressure control means for controlling the source pressure of the fuel gas;
The gas injection device according to claim 1, further comprising: