JP2915719B2 - Burner for hydrochloric acid synthesis - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burner for synthesizing hydrochloric acid, and more particularly, to a burner used in an apparatus for producing synthetic hydrochloric acid by a combustion method.

[0002]

2. Description of the Related Art As a burner used for synthesizing hydrochloric acid by burning and reacting chlorine gas and hydrogen gas, an inner cylinder for supplying chlorine, an outer cylinder for supplying hydrogen, and a burner for preventing dispersion of a flame are used. The one having a flame tube and a pilot tube for ignition has been conventionally used, and a general one is shown in FIG.

As is apparent from FIG. 3, in a burner for synthesizing hydrochloric acid which has been widely used in recent years, a pilot tube 9 is used.
Inner tube for chlorine supply 4 (made of impervious graphite) equipped with (made of quartz)
The outer cylinder 7 for hydrogen supply arranged outside the inner cylinder is divided into two near the upper surface of the inner cylinder 4, the lower tubular part 7 a is formed of graphite, and the upper parts 7 b and 7 c are made of quartz together with the flame holding tube 8. It was integrally molded (the integrally molded product of the outer cylinder upper parts 7b and 7c and the flame holding tube 8 is called a cap 18). With such a configuration, the upper portion 7b, 7c of the outer cylinder, in particular, the upper inner wall portion 7 of the outer cylinder which has the hydrogen ejection holes 6 and is exposed to the high-temperature flame.
The deterioration of c was prevented to some extent.

However, in the conventional burner shown in FIG. 3, since the upper portions 7b and 7c of the outer cylinder are made of quartz, a sealing portion 1 with the lower tubular portion 7a is taken into consideration in consideration of deformation due to heat.
0 needs to be an inro joint structure as shown in FIG.
The passage 5 for flowing hydrogen was partially narrow. Therefore, in the conventional burner, impurities mainly composed of ammonium chloride generated by the reaction of ammonia usually mixed in hydrogen by electrolysis with chlorine leaking from the sealing portion of the inner cylinder / cap, etc. Settled in this narrow area,
There is a disadvantage that the hydrogen passage 5 is blocked. Therefore, when such a conventional burner is used, it is necessary to perform maintenance (disassembly, cleaning, repair, etc.) about every 20 days, and the burner life is about one year.

In view of the above, a burner for synthesizing hydrochloric acid which does not cause blockage of the hydrogen passage 5 has been desired, and a burner shown in FIG. 4 has been developed as such a burner for synthesizing hydrochloric acid.
In the burner shown in FIG. 4, the upper portions 7b and 7c of the outer cylinder are formed of a graphite material coated with silicon carbide having excellent heat resistance separately from the flame holding tube 8 made of quartz. In this case, if the lower tubular portion 7a is made of a graphite material having the same thermal expansion coefficient as the outer cylinder upper portions 7b and 7c formed of the silicon carbide-coated graphite material,
4 and 7c and the lower tubular portion 7a can be simply connected as shown in FIG. 4 without particularly having an inro joint structure (seal portion 10). Therefore, there is no narrow portion in the hydrogen passage 5 of the burner shown in FIG.

However, in the conventional burner shown in FIG. 4, the upper portion of the outer cylinder is divided into the upper tubular portion 7b and the inner wall portion 7c, so that the inner wall portion exposed to the high-temperature flame during operation. A disadvantage is that the temperature of the sealing portion 11 between the upper tubular portion 7c and the upper tubular portion 7b becomes high, and graphite and hydrogen cause a methane reaction in the vicinity of the portion 11, thereby reducing the thickness of the inner wall portion 7c and the sealing portion 11, and causing breakage or leakage of hydrogen. was there.
Therefore, even when the burner shown in FIG. 4 is used, it is necessary to perform maintenance every about one month, and the life of the burner is hardly improved as compared with the conventional burner shown in FIG. 3, and it is still not enough. .

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and provides a burner for synthesizing hydrochloric acid which can be used for a long time without maintenance and has a long life. It is intended to do so.

[0008]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have formed at least the upper tubular portion and the inner wall portion with a silicon carbide-coated graphite material, and formed the upper end portion of the inner wall portion with the upper tubular portion. The present inventors have found that the above problem can be solved by sandwiching the inner wall portion and the upper tubular portion so as not to be directly exposed to the flame by being sandwiched between the portion and the flame holding tube, and reached the present invention.

That is, the burner for synthesizing hydrochloric acid of the present invention comprises:
A chlorine supply inner cylinder having a chlorine passage formed therein and a chlorine ejection hole provided on an upper surface thereof; and a hydrogen passage extending above the inner cylinder upper surface around the inner cylinder together with the inner cylinder, and A hydrogen supply outer cylinder provided with a hydrogen ejection hole for ejecting hydrogen inward above the upper surface of the inner cylinder; a flame holding tube attached to an upper portion of the outer cylinder; and an upper end inserted into the inner cylinder and having an upper end. A burner for synthesizing hydrochloric acid, comprising a pilot tube protruding from the upper surface of the inner tube: an outer tube, a lower tubular portion, and an upper tubular portion mounted on the upper end of the lower tubular portion without narrowing the hydrogen passage; The upper end is constituted by the upper tubular portion and the inner wall portion which is sandwiched by the flame holding tube and the lower end is attached to the inner tube, and at least the upper tubular portion and the inner wall portion are made of a silicon carbide-coated graphite material. Is also characterized by It is.

Further, in the burner for synthesizing hydrochloric acid according to the present invention, a sealing portion between the upper tubular portion and the inner wall portion, a sealing portion between the upper tubular portion and the lower tubular portion, and a sealing portion between the upper tubular portion and the lower tubular portion. It is preferable to attach the sealing portions to the chlorine supply inner cylinder via gaskets made of expanded graphite, since the adhesion and the heat resistance thereof are significantly improved.

[0011]

The graphite material coated with silicon carbide has excellent heat resistance, and the inner wall portion and the upper tubular portion made of the graphite material coated with silicon carbide do not wear out even when exposed to a high-temperature flame for a long time.

Further, if a graphite material having a thermal expansion coefficient equivalent to that of the silicon carbide-coated graphite material is selected and used, even if the contact area of the sealing portion between the upper tubular portion and the lower tubular portion is small, the material does not loosen during heating. There is no inconvenience even if the thickness of the sealing portion is the same as other portions. Therefore, it is possible to eliminate a narrow portion of the hydrogen passage, and there is no partial deposition of ammonium chloride or the like in the narrow portion, so that the hydrogen passage is not blocked for a long time.

Furthermore, in the burner for synthesizing hydrochloric acid of the present invention, since the sealing portion between the inner wall portion and the upper tubular portion is not directly exposed to the flame, the methane reaction between graphite and hydrogen near the sealing portion is sufficiently suppressed. This prevents the inner wall portion and the sealed portion from being reduced in thickness and damaged.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing one example of a burner for synthesizing hydrochloric acid of the present invention.

A burner 1 for synthesizing hydrochloric acid shown in FIG. 1 has a chlorine passage 2 formed therein and a chlorine supply inner cylinder 4 provided with a chlorine ejection hole 3 on the upper surface; A hydrogen supply outer cylinder 7 having a hydrogen passage 5 extending upward and formed with the inner cylinder 4 and having a hydrogen ejection hole 6 for ejecting hydrogen inward above the upper surface of the inner cylinder 4; It comprises a flame holding tube 8 mounted on the upper part, and a pilot tube 9 inserted into the center of the inner cylinder 4 and having an upper end projecting toward the center of the upper surface of the inner cylinder 4.

Further, the outer tube 7 for supplying hydrogen is composed of three members, a lower tubular portion 7a, an upper tubular portion 7b, and an inner wall portion 7c, and a sealing portion 10 between the lower tubular portion 7a and the upper tubular portion 7b is formed. The hydrogen passage 5 is in close contact without being narrowed. The inner wall portion 7c is sandwiched between the upper end portion of the upper tubular portion 7b and the lower end portion of the flame holding tube 8, so that the sealing portion 11 between the inner wall portion 7c and the upper tubular portion 7b is not directly exposed to flame. I have. Further, the lower end of the inner wall 7c is
The upper tubular portion 7a, the upper tubular portion 7b, the inner wall portion 7c
A hydrogen passage 5 is formed by the inner cylinder 4.

At least the upper tubular part 7b and the inner wall part 7c of the above-mentioned constituent members are coated with a silicon carbide coating on the surface.
It is formed of a graphite material formed by the D method or the like. By using such a graphite material, erosion and the like of the above-mentioned members due to flame can be significantly reduced, and loosening of the seal portion 10 can be completely prevented. In the present invention, the upper tubular portion 7 described above is used.
Other materials may be appropriately selected for the constituent members other than b and the inner wall portion 7c. Quartz is used for the pilot tube 9 and the flame holding tube 8, graphite is used for the lower tubular portion 7a, and impervious graphite is used for the inner tube 4. (Resin-impregnated graphite) is preferably used.

Sealing parts 10, 11, 12 of each component
Need to adhere closely so that no gas leaks out of it,
It is preferable to adhere through a gasket excellent in heat resistance, and it is particularly preferable to adhere through an expanded graphite gasket. The gasket made of expanded graphite is excellent in heat resistance and adhesion, and significantly improves the durability of each sealing portion. Further, each sealing portion may be configured to be a fitting type or a screw type.

Next, an example of an apparatus and a method for synthesizing hydrochloric acid using the hydrochloric acid synthesizing burner 1 having the above configuration will be described with reference to FIG. FIG. 2 is a schematic diagram showing an example of a hydrochloric acid synthesizing apparatus using the burner for synthesizing hydrochloric acid of the present invention.

In FIG. 2, a burner 1 for synthesizing hydrochloric acid is disposed at a lower end of a combustion tower 13, a chlorine supply pipe 14 and an air supply pipe 15 are provided in a chlorine passage 2, and a hydrogen supply pipe 1 is provided in a hydrogen passage 5.
6. A hydrogen supply pipe 16 and an air supply pipe 15 are connected to the pilot pipe 9, respectively. Each supply pipe is provided with a flow control valve (not shown), and a supply pipe to the pilot pipe 9 is provided with ignition means 17.

In the case of synthesizing hydrochloric acid using the hydrochloric acid synthesizing system thus configured, first, while supplying hydrogen and air to the pilot tube 9, the pilot tube 9 is ignited by the ignition means 17 to illuminate a pilot flame at the tip of the pilot tube 9. Next, hydrogen is supplied to the hydrogen passage 5 and air is supplied to the chlorine passage 2 to generate a hydrogen combustion flame, and the supply of air to the pilot pipe 9 is cut off. Then, by completely replacing the gas supplied to the chlorine passage 2 with chlorine, the hydrogen ejected from the hydrogen ejection holes 6 and the chlorine ejected from the chlorine ejection holes 3 undergo a combustion reaction to generate a synthetic hydrochloric acid flame. The hydrochloric acid gas thus synthesized is recovered by cooling and recovering means (not shown) to obtain hydrochloric acid.

The mixing ratio of hydrogen and chlorine is usually such that hydrogen is slightly excessively supplied in order to prevent the generation of free chlorine. For example, it is preferable that about 95 mol of chlorine is added to 100 mol of hydrogen.

[0024]

As described above, in the burner for synthesizing hydrochloric acid of the present invention, the generation and deposition of ammonium chloride in the hydrogen passage are extremely small, and the burner is not blocked as in the conventional burner. In addition, the components, particularly the inner wall, are not worn, and the reduction in the thickness and the breakage of the sealing portion between the inner wall and the upper tubular portion are completely prevented.

Accordingly, by using the burner for synthesizing hydrochloric acid of the present invention, it is only necessary to perform maintenance every about six months, and the maintenance period is about nine times as compared with the conventional burner of FIG.
Since it is more than twice as long as that of the conventional burner of FIG. 2, it is very excellent in terms of simplicity of maintenance.

The life of the burner for synthesizing hydrochloric acid of the present invention is about three years, which is about three times longer than that of the conventional burner shown in FIGS.

Further, the use of the burner for synthesizing hydrochloric acid of the present invention makes it possible to improve the economic efficiency and production efficiency of synthesizing hydrochloric acid.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a burner for hydrochloric acid synthesis of the present invention.

FIG. 2 is a schematic diagram showing an example of a hydrochloric acid synthesizing apparatus using the hydrochloric acid synthesizing burner of the present invention.

FIG. 3 is a longitudinal sectional view showing a conventional general burner for synthesizing hydrochloric acid.

FIG. 4 is a longitudinal sectional view showing another example of a conventional burner for synthesizing hydrochloric acid.

[Explanation of symbols]

1: burner for synthesizing hydrochloric acid, 2: chlorine passage, 3: chlorine discharge hole, 4: chlorine supply inner cylinder, 5: hydrogen passage, 6: hydrogen discharge hole, 7: hydrogen supply outer cylinder, 7a: lower tubular portion , 7b: upper tubular portion, 7c: inner wall portion, 8: flame holding tube, 9: pilot tube, 10 to 12: sealed site, 13: combustion tower, 14: chlorine supply tube, 15: air supply tube, 16: hydrogen Supply pipe, 1
7: ignition means, 18: cap.

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Koji Ishikawa 5-8 Urashima-cho, Kanagawa-ku, Yokohama-shi, Kanagawa-ken (58) Field surveyed (Int. Cl. ⁶ , DB name) B01J 12/00 C01B 7/01

Claims (2)

(57) [Claims] 1. A chlorine supply inner cylinder having a chlorine passage formed therein and a chlorine ejection hole formed on an upper surface thereof, and a hydrogen passage extending around the inner cylinder and extending above the upper surface of the inner cylinder together with the inner cylinder. A hydrogen supply outer cylinder formed and provided with a hydrogen ejection hole for ejecting hydrogen inward above the upper surface of the inner cylinder; a flame holding tube mounted on an upper portion of the outer cylinder; and In a hydrochloric acid synthesizing burner having a pilot tube inserted and having an upper end protruding from the upper surface of the inner cylinder, the outer cylinder is attached to the upper end of the lower tubular part without narrowing the hydrogen passage. The upper tubular portion, the upper end is sandwiched by the upper tubular portion and the flame holding tube, and the lower end is configured by an inner wall portion attached to the inner cylinder,
A burner for hydrochloric acid synthesis, characterized in that at least the upper tubular part and the inner wall part are made of a silicon carbide-coated graphite material. 2. A sealing portion between the upper tubular portion and the inner wall portion, a sealing portion between the upper tubular portion and the lower tubular portion, and a sealing portion between the inner wall portion and the inner tube for supplying chlorine are each expanded. 2. The hydrochloric acid synthesis burner according to claim 1, wherein the burner is mounted via a graphite gasket.