JP3484536B2 - Combustion unit for producing carbon monoxide and hydrogen - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a combustion device for producing carbon monoxide and hydrogen, and more particularly to a combustion device capable of efficiently producing carbon monoxide and hydrogen used as raw materials for synthesizing organic substances.

[0002]

2. Description of the Related Art As a method for producing carbon monoxide or hydrogen as a raw material for synthesizing various organic substances, carbonaceous or hydrocarbonaceous fuel is prepared by using oxygen having an oxygen ratio of less than 1.0. A method is known in which a combustion gas containing carbon monoxide and hydrogen is obtained by combusting with.

However, when a normal burner is used to burn a fuel with an oxygen ratio of less than 1.0, thermal decomposition of the fuel causes methane (CH ₄ ) and acetylene (C ₂ H ₂ ) to be burned.
Since impurities such as lower hydrocarbons and soot (carbon) are also produced in large amounts, the yield of the target carbon monoxide and hydrogen is reduced.

Therefore, for example, Japanese Patent Laid-Open No. 19120/1993
In the method described in Japanese Patent Publication No. 1, butane as a fuel, an oxidizer (oxygen or oxygen-containing gas) and water vapor are ejected from a burner at a specific ratio and burned in a state containing water vapor to generate soot. Is trying to suppress.

However, although the method of adding steam as described above can suppress the generation of soot, since a large amount of steam is added, the theoretical carbon monoxide and hydrogen predicted from the thermal equilibrium calculation are added. However, there is a problem in that the yield of is reduced.

In addition, in the general method of adding steam, the steam is added to and mixed with the fuel, and the steam is ejected from the nozzle between the fuel nozzle and the oxidizer nozzle. There is a problem in that the fuel will reach a high temperature region without contacting oxygen and will be thermally decomposed to generate lower hydrocarbons.

For example, when the generation ratio of hydrogen to carbon monoxide is set to 0.6, that is, H ₂ /CO=0.6, carbon dioxide is added as a regulator. At this time, in order to prevent the generation of soot, it is necessary to add steam in proportion to the amount of carbon dioxide added, but as the amount of steam added increases, the combustion temperature (reaction temperature)
Therefore, there is a limit to the suppression of soot generation, and it becomes difficult to obtain a desired H ₂ / CO ratio. Further, the amount of lower hydrocarbons generated also increases in proportion to the amount of carbon dioxide added.

[0008] Therefore, an object of the present invention is to provide a combustion apparatus for producing carbon monoxide and hydrogen, which can efficiently produce carbon monoxide and hydrogen while suppressing generation of lower hydrocarbons and soot.

[0009]

In order to achieve the above object, a combustion apparatus for producing carbon monoxide and hydrogen according to the present invention burns carbon monoxide and hydrogen by burning with an oxygen ratio to a fuel of less than 1.0. a combustion apparatus for generating, said
Combustion apparatus includes a cylindrical combustion chamber, or one end of the cylindrical combustion chamber
And a burner that is inserted coaxially from the burner.
At the tip, the injection direction spreads with the central axis of the combustion chamber as the axis.
A truncated cone-shaped nozzle portion is provided, and a regulator agent nozzle for ejecting a regulator agent in the direction of the central axis of the combustion chamber, and a fuel from the outer periphery of the regulator agent nozzle in the direction parallel to the central axis of the combustion chamber are provided in the nozzle portion. A fuel nozzle that ejects and an oxidant nozzle that ejects the oxidant from the outer periphery of the fuel nozzle so as to have a focal point on the center axis of the combustion chamber are provided .
Is also located forward of the central axis of the combustion chamber, and the oxidizer is ejected.
The speed is equal to or higher than the jet speed of the fuel, and the jet of the fuel is
The ejection speed is set to be equal to or higher than the ejection speed of the adjusting agent .

Further, the jetting rate of the oxidant with respect to the jetting rate of the fuel is 1.0 to 1. Set to 4, again
The length of the combustion chamber in the central axis direction is 1.
2 to 1.6 times, the nozzle portion forms one end surface of the combustion chamber, and the distance from the fuel nozzle to the focal point is the same as the inner diameter of the combustion chamber. it is, furthermore, injection direction of the oxidizing agent to the focal point is characterized in that is 45 degrees with respect to the combustion chamber central axis.

[0011]

FIG. 1 is a cross-sectional view showing an embodiment of a carbon monoxide / hydrogen generating combustion apparatus according to the present invention. In this combustion device 10 for producing carbon monoxide and hydrogen, a burner 12 is coaxially inserted from one end of a cylindrical combustion chamber 11 formed of a refractory material, and the center of the combustion chamber 11 is provided at the tip of the burner 12. A truncated cone-shaped nozzle portion 14 is provided in which the ejection direction is expanded with the shaft 13 as an axis.

The nozzle portion 14 forms one end surface of the combustion chamber 11. The nozzle portion 14 has an adjusting agent nozzle 15 for ejecting an adjusting agent and a fuel nozzle 16 for ejecting fuel. An oxidant nozzle 17 for ejecting the oxidant is provided.

A water cooling jacket 18 for protecting the burner 12 from a high temperature environment is provided on the outer periphery of the burner, and an inner peripheral side of the water cooling jacket 18 is provided with a passage 15a for the adjusting agent, fuel, and oxidizer. , 16a, 17a are formed.

The adjusting agent nozzle 15 is provided at the center of the nozzle portion 14, and ejects an adjusting agent for controlling the above-mentioned H ₂ / CO ratio, such as carbon dioxide or water vapor, toward the central axis 13. Is formed.

The fuel nozzle 16 provided on the outer periphery of the adjusting agent nozzle 15 is provided in an annular shape on the circumference centered on the central axis 13, and ejects fuel in a direction parallel to the central axis 13. Is formed.

The oxidant nozzle 17 is the fuel nozzle 1
6 is provided so as to surround the outer periphery of the fuel cell 6 and is concentric with the fuel nozzle 16, that is, the central axis 1
It is provided in an annular shape centering on 3 and having a diameter larger than that of the fuel nozzle 16. The oxidant nozzle 14 is formed so as to eject the oxidant inward so as to have a focal point 19 on the central axis 13.

In the combustion device 10 thus formed, the fuel ejected from the fuel nozzle 16 reacts with the oxidant ejected from the oxidant nozzle 17, for example, oxygen, and burns. A high temperature area is formed in the area. At this time, at the interface between the fuel and oxygen, complete combustion is locally generated to generate carbon dioxide and water vapor, and the oxygen ratio with respect to the fuel is set to less than 1.0. A large amount of soot is generated from this, and lower hydrocarbons are generated by the thermal decomposition of unburned fuel.

The soot produced reacts with oxygen or carbon dioxide or water vapor produced by complete combustion or carbon dioxide or water vapor added as a modifier at a high temperature to react with them, and two carbon atoms and one molecule. Reacting with the oxygen in the carbon dioxide produces two molecules of carbon monoxide,
When one reacts with one molecule of carbon dioxide, two molecules of carbon monoxide are produced, and when one carbon atom reacts with one molecule of water vapor, one molecule of carbon monoxide and one molecule of hydrogen are produced. Similarly, lower hydrocarbons also generate carbon monoxide and hydrogen by contacting and reacting with oxygen, carbon dioxide, and water vapor at high temperature.

The fuel nozzle 16 and the oxidant nozzle 1
By disposing 7 and 7 as described above, it is possible to form a shielding layer that wraps the fuel ejected from the fuel nozzle 16 by the oxygen ejected from the oxidant nozzle 17. The shielding layer suppresses the regulator and the fuel from jumping out to the high temperature region in the combustion chamber 11 by themselves without thermal contact with oxygen and thermally decomposing to generate soot. In other words, this shielding layer burns the soot generated at the interface between the fuel and oxygen, together with carbon dioxide and water vapor generated by the local complete combustion at the interface between the fuel and oxygen, without directly ejecting the soot. It is confined in the region, and these are mixed and reacted in the combustion region to act to generate carbon monoxide and hydrogen as described above.

Further, even if soot or the like is blown out through the shielding layer, the soot is retained in the high temperature combustion chamber 11 without being dispersed, so that oxygen, carbon dioxide and water vapor are kept in the high temperature atmosphere in the combustion chamber 11. Reacts with to produce carbon monoxide and hydrogen.

Therefore, the product gas obtained by the combustion in the combustion device 10 contains almost no soot or lower hydrocarbons but a large amount of carbon monoxide or hydrogen.

The forms of generation of carbon monoxide and hydrogen as described above include the diameter and length of the combustion chamber 11, the shape of the nozzle portion 14, the type of fuel, the oxygen concentration of the oxidant, and the required H ₂ / CO ratio. ,
It is formed by selecting an optimal state through experiments or the like according to the permissible amount of soot or the like as an impurity, but generally, the ejection speed of the oxidant ejected from the oxidant nozzle 17 is The shielding layer can be effectively created by making the ejection speed of the fuel ejected from the fuel nozzle 16 faster. The ratio of the jetting speed of the oxidant to the jetting speed of the fuel (velocity ratio) varies depending on the conditions, and normally, if the jetting speed of the oxidant to the jetting speed of the fuel is 0.8 or more, the generation of soot is suppressed. However, it is preferable that the jetting rate of the oxidant with respect to the jetting rate of the fuel is about 1.0 to 1.4. However, if the speed ratio is set too high, free O ₂ (unreacted oxygen) may be generated or a normal combustion state may not be obtained. Further, when the ejecting speed of the adjusting agent becomes faster, the ejected adjusting agent easily penetrates through the shielding layer, so it is preferable to make it slower than the ejecting speed of the fuel.

Further, the fuel nozzle 16 is replaced with the oxidant nozzle 17
By arranging in the vicinity of, the fuel can be efficiently sucked into the jet of oxygen jetted from the oxidant nozzle 17, and the combustion reaction can be promoted. Further, when the fuel nozzle 16 and the oxidizer nozzle 17 are formed with small through holes as shown in FIG. 1, it is preferable that the fuel nozzle 16 and the oxidant nozzle 17 are arranged so as to be as close to a circle as possible with a space as narrow as possible. In addition, the nozzles 16 and 1 can be formed by combining pipes and spacers having different diameters.
By forming 7 into a ring shape consisting of continuous slits, the fuel and oxygen can be brought into contact with each other uniformly, so that a more effective combustion reaction can be obtained.

Further, the fuel nozzle 16 and the oxidant nozzle 1
When the fuel nozzle 16 projects forward from the oxidant nozzle 17, the fuel ejected from the fuel nozzle 16 easily penetrates through the oxidant shielding layer. Should be located at. Therefore, although the nozzle shape is inevitably shown in FIG. 1, the divergence angle in the truncated cone is arbitrary and may be close to a plane.

The length of the combustion chamber 11 may be set according to the ejection speed from each nozzle, the flame length, etc., so that the desired gas composition can be obtained at the outlet of the combustion chamber 11.
However, if the combustion chamber 11 is made too short, the action of the combustion chamber 11 may not be sufficiently obtained, and the amount of lower hydrocarbons generated may increase. Therefore, set the length equal to or larger than the diameter of the combustion chamber 11. Is preferable, and the longer the length, the more effective. However, if the combustion chamber 11 is made too long, the amount of wear of the refractory material due to the flame increases, which is uneconomical. Therefore, it is usually 1.2 to 1.6 times the diameter of the combustion chamber 11. Is preferred.

Further, the amounts of the fuel and the oxidizer differ depending on the type of the fuel, and if the amount of oxygen in the fuel is not less than the amount of oxygen capable of converting carbon into carbon monoxide and the oxygen ratio to the fuel is less than 1.0, It is possible to generate carbon monoxide and hydrogen while suppressing the generation of impurities such as soot by the combustion reaction. However, in general, the lower the oxygen ratio, the more the production amount of carbon monoxide and hydrogen increases, but the temperature of the flame decreases, and the reaction becomes difficult to realize. Therefore, for example, when the fuel is propane (C ₃ H ₈ ), by setting the oxygen ratio in the range of 0.3 to 0.6, preferably about 0.45, it is possible to obtain a flame that is sufficient to cause a reaction. The temperature can be obtained, the generation efficiency of carbon monoxide and hydrogen can be improved, and carbon monoxide and hydrogen can be obtained in high yield.

The position of the focal point 19 (distance from the nozzle) in the oxidant nozzle 17 also varies depending on various conditions, but it is appropriate that the distance is about the same as the inner diameter of the combustion chamber 11 and the angle with respect to the central axis 13 is about 45 degrees. , The focal point 19 is too far away, the combustion reaction becomes slow, and when the focal point 19 is too close, jets of the oxidizer collide violently with each other, so that turbulence occurs in the gas flow and combustion becomes non-uniform. Yes, it may adversely affect the combustion reaction. Further, the direction of fuel injection may be substantially parallel to the burner central axis,
It may be slightly outward or inward.

The fuel is preferably a gaseous fuel such as LPG, LNG or butane, but a liquid fuel such as kerosene, heavy oil or light oil, a solid fuel such as pulverized coal, or a mixture thereof can be used. . Further, as the oxidant, it is optimal to use oxygen gas from the viewpoint that a high temperature region can be efficiently formed, but oxygen-enriched gas having an oxygen concentration of about 80% may be used, and air may be used depending on conditions. Is also possible.

In addition, an adjusting agent added as necessary to adjust the H ₂ / CO ratio is added to the central adjusting agent nozzle 15
By injecting the fuel at a low speed, the contact between the fuel and the oxidant can be prevented and the gas or soot generated by the combustion can be effectively contacted.

Since the generation of soot and lower hydrocarbons can be suppressed and carbon monoxide and hydrogen can be obtained in a high yield in this manner, the H ₂ / CO ratio to be produced can be easily predicted from the thermal equilibrium calculation. It becomes possible to do. Further, since it is not necessary to add a large amount of steam to suppress the generation of soot, the furnace for combustion can be downsized, and in addition, since the amount of lower hydrocarbons is small, these are removed by a catalyst or the like. Without this, processing such as boosting is possible. Therefore, the initial cost of the entire device can be significantly reduced.

[0031]

EXAMPLES Examples 1 and 2 A combustion apparatus for producing carbon monoxide and hydrogen having the structure shown in FIG. 1 was used. In this combustion device, the diameter of the combustion chamber is 70 mm, the distance from the nozzle end to the outlet is 100 mm, and the opening angle of the nozzle is about 60 degrees. Adjuster nozzle diameter is 2
The number of fuel nozzles was 3 mm, and eight fuel nozzles were installed at equal intervals on a circumference having a diameter of 34 mm around the central axis. The jetting direction was set at an angle of 45 degrees with respect to the central axis, and 24 oxidant nozzles were installed at equal intervals on a circumference having a diameter of 53.4 mm centered on the central axis.

The combustion apparatus 10 was installed in the experimental furnace 21 as shown in FIG. 2, and the combustion product gas discharged to the flare stack 22 connected to the facing surface was sampled by the sampling probe 23.

Using LPG as fuel, 10 m ³ /
The oxygen gas having a purity of 99.8% is supplied as the oxidant at 20.0 m ³ / h in Example 1 and 2 in Example 2.
It was supplied at 2.5 m ³ / h. No regulator was added.

Soot concentration in the sampled gas (the amount of untwisted carbon measured by sampling with respect to the carbon contained in the injected fuel, expressed as a percentage),
As a result of measuring the oxygen concentration, carbon dioxide concentration, methane concentration, and acetylene concentration, respectively, the yields of carbon monoxide and hydrogen (the total amount of carbon monoxide and hydrogen with respect to the amount of gas produced, expressed as a percentage), H Table 1 shows the measured and theoretical values of the ₂ / CO ratio.

[0035]

[Table 1]

Examples 3 to 10 Using the same apparatus as in Example 1, the supply amount of LPG as fuel was 10 m ³ / h and the supply amount of oxygen gas as an oxidant was 22.5 m.
³ / h, and steam or carbon dioxide as a regulator was added at the flow rates shown in Table 2.

Table 2 shows the soot concentration, methane concentration, acetylene concentration, yields of carbon monoxide and hydrogen, measured values and theoretical values of H ₂ / CO ratio in the produced gas.

[0038]

[Table 2]

[0039]

As described above, according to the combustion apparatus for producing carbon monoxide and hydrogen of the present invention, it is possible to efficiently produce carbon monoxide and hydrogen while suppressing the generation of soot and lower hydrocarbons. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of one embodiment of a combustion apparatus of the present invention.

FIG. 2 is a sectional view of the experimental furnace used in the examples.

[Explanation of symbols]

10 ... Combustion device, 11 ... Combustion chamber, 12 ... Burner, 13
... central axis, 14 ... nozzle part, 15 ... adjusting agent nozzle, 16
... Fuel nozzle, 17 ... Oxidizer nozzle, 18 ... Water cooling jacket, 19 ... Focus, 21 ... Experimental furnace, 22 ... Flare stack, 23 ... Sampling probe

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Miyake 1-16-7 Nishishinbashi, Minato-ku, Tokyo Nihon Oxygen Co., Ltd. (72) Inventor Kimio Iino 1-16-7 Nishishinbashi, Minato-ku, Tokyo Japan Oxygen Co., Ltd. (72) Inventor Shingo Murakami 1-16-7 Nishi-Shimbashi, Minato-ku, Tokyo Nihon Oxygen Co., Ltd. (72) Inventor Yotarou Ono 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan KK (72) Inventor, Keiichi Okuyama, 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Nippon Kokan Co., Ltd. (56) References JP-A-2-239101 (JP, A) JP-A-2-25615 (JP, A) ) JP-A-3-191201 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C01B 3/36 F23C 11/00

Claims (6)

(57) [Claims] 1. A combustion device for producing carbon monoxide and hydrogen by burning with an oxygen to fuel ratio of less than 1.0, the combustion device comprising a cylindrical combustion chamber and the cylindrical combustion chamber. A burner that is inserted coaxially from one end of the burner, and a truncated cone-shaped nozzle portion whose ejection direction is expanded with the central axis of the combustion chamber as an axis is provided at the tip of the burner, and the combustion chamber center is provided in the nozzle portion. A regulator nozzle that ejects a regulator in the axial direction, a fuel nozzle that ejects fuel from the outer periphery of the regulator nozzle in a direction parallel to the combustion chamber central axis, and a focus from the outer periphery of the fuel nozzle on the center axis of the combustion chamber. And an oxidant nozzle for ejecting an oxidant so that the oxidant nozzle is located forward of the fuel nozzle in the direction of the central axis of the combustion chamber, and the ejection speed of the oxidant is equal to or higher than the ejection speed of the fuel. And the injection of the fuel A combustor for producing carbon monoxide and hydrogen, characterized in that the ejection speed is equal to or higher than the ejection speed of the adjusting agent. 2. The jetting rate of the oxidant with respect to the jetting rate of the fuel is 1.0 to 1. 4. The combustion apparatus for carbon monoxide and hydrogen generation according to claim 1, wherein the combustion apparatus is set to 4 . 3. The carbon monoxide according to claim 1, wherein the length of the combustion chamber in the central axis direction is set to 1.2 to 1.6 times the diameter of the combustion chamber. Combustion device for hydrogen generation. 4. The nozzle section forms one end surface of the combustion chamber, according to any one of claims 1 to 3.
A combustion device for producing carbon monoxide and hydrogen according to the above item. 5. The carbon monoxide and hydrogen generating device according to claim 1, wherein a distance from the fuel nozzle to the focal point is the same as an inner diameter of the combustion chamber. Combustion device. 6. The jetting direction of the oxidant with respect to the focus is
The combustion apparatus for producing carbon monoxide and hydrogen according to any one of claims 1 to 4, wherein the combustion chamber central axis is 45 degrees .