JP2003014300A - Steam type throw-in heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam type throw-in heater exhibiting excellent heat transfer property and applicable even to a high concentration acid solution, and a steam type heater comprising that heater. SOLUTION: The steam type throw-in heater comprises a heater pipe having one closed end and the other capped end fixed with a steam supply path, and a drain pipe wherein the material of the heater pipe comprises silicon-silicon carbide. A steam type heater comprising that heater is also provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam type throw-in heater and a steam type heating device equipped with the heater.

[0002]

2. Description of the Related Art A steam type throw-in heater is a part of a heating device used for raising a liquid temperature by immersing it in a liquid tank. For example, a cleaning solution for a metal plate (acid such as hydrochloric acid or sulfuric acid) is used. Solution), a plating solution, etc.

FIG. 1 shows an example of a steam type heating device using a steam type throw-in heater. Boiler 1
The steam generated in 0 (steam supply device) is usually passed through the pressure reducing valve 11 to the throw-in heater A immersed in the liquid tank 12 and then to 1
It is introduced as high-pressure steam at about 50 ° C., where it liquefies itself and is discharged through the steam trap 13 while heating the liquid in the liquid tank 12 through the pipe wall.

At present, as the heater tube of the steam type throw-in heater, those made of stainless steel or ceramics such as silicon carbide are mainly used. However, since a stainless steel heater tube has poor corrosion resistance, it cannot be used for heating highly corrosive solutions such as hydrochloric acid and sulfuric acid. Further, since stainless steel has low heat conductivity, it is not possible to efficiently heat the solution in the liquid tank.

As described above, the conventional stainless steel steam cast-in heater cannot be applied to a high-concentration acid solution, and is inferior in heat conductivity. Conventionally used heater tubes made of ceramics such as silicon carbide have improved heat conductivity as compared with stainless steel, but heater tubes having more excellent heat conductivity are desired.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a steam type throw-in heater which can be applied to a high-concentration highly corrosive solution and has excellent heat transfer efficiency.

[0007]

The present inventor has found that the above object can be achieved by using a heater tube made of a silicon-silicon carbide composite material as a heater tube of a steam type throw-in heater, and has completed the present invention. I arrived. That is, the present invention provides the invention according to the following items. Item 1 A steam-type throw-in heater having a heater tube having one end closed and a cap provided with a steam supply path at the other end, and a drain tube, wherein the material of the heater tube is silicon and silicon carbide. A steam-type throw-in heater characterized by being a mixture of Item 2. The steam-type throw-in heater according to Item 1, wherein the mixture of silicon and silicon carbide is obtained by dispersing silicon carbide in silicon. Item 3. The steam-type throw-in heater according to Item 2, wherein the mixture of silicon and silicon carbide obtained by dispersing silicon carbide in silicon is a sintered body of silicon and silicon carbide. Item 4. The steam-type throw-in heater according to Item 1, wherein the mixture of silicon and silicon carbide is obtained by impregnating silicon carbide with silicon. Item 5 A steam heating device comprising the steam throw-in heater according to any one of items 1 to 4 and a steam feeder.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

FIG. 2 shows an example of the structure of the steam throw-in heater according to the present invention. The steam supply passage 3 is provided on the other end (open end) side of the heater tube 1 which is closed at one end. The cap 2 is attached by the flange 5, the bolt 6 and the nut 7, and the tip end extends to the vicinity of the closed end of the heater tube 1, and the drain tube 4 which penetrates the cap 2 and communicates to the outside is provided.

FIG. 3 shows another example of the structure of the steam type throw-in heater of the present invention. A screw is provided at the open end of the heater tube 1'so that they can be joined to each other, and the steam supply path 3'is formed. A cap 2'is attached to the heater tube 1'by cutting a female screw at the bottom of the cap 2'provided.

It suffices for the heater tube to be closed at one end and open at the other end. For example, powder of silicon and silicon carbide is molded into the shape of a heater tube as shown in FIG. It can be obtained by sintering, or by molding silicon carbide into such a shape and sintering it, and immersing the molded body in molten high-temperature silicon. Further, a rod-shaped molded product of a mixture of silicon and silicon carbide can be obtained by shaving a dome-shaped closed end at one end and an open end at the other end.

Alternatively, as shown in FIG. 4, it is a heater tube 1 '' in which a closing member 9 made of a mixture of silicon and silicon carbide is attached to one end of a pipe 8 of a mixture of silicon and silicon carbide which is open at both ends. May be. When the heater tube is manufactured from the pipe and the closing member, it is preferable because it is easy to process. The shape of the closing member is not particularly limited as long as it can close one end of the pipe. The pipe and the blocking member can be attached by, for example, threading the female thread on the pipe and the thread on the blocking member. Alternatively, cement may be used to join the closure member to the pipe.

In the present invention, the mixture of silicon and silicon carbide includes a mixture in which silicon carbide is dispersed in silicon and a mixture in which silicon carbide is impregnated with silicon.

Examples of the mixture in which silicon carbide is dispersed in silicon include a sintered body of silicon and silicon carbide, and a mixture of molten silicon and silicon carbide.

The silicon and silicon carbide sintered body is prepared by uniformly mixing powders of silicon and silicon carbide having an average particle size of about 1 to 1000 μm, preferably about 1 to 100 μm, and a suitable sintering aid, A binder, a plasticizer, and a solvent are added and kneaded, and the mixture is molded according to a conventional method, and then in an inert gas such as nitrogen or argon at about 1500 to 2500 ° C., preferably about 1600 to 2000 ° C. for 0.5 to 24 hours. It can be obtained by firing for about 1 to 10 hours. As the sintered body of silicon and silicon carbide, a commercially available product such as a high temperature ceramic material “Rikurite (trade name)” manufactured by Tokai High Temperature Industrial Co., Ltd. may be used.

As the sintering aid, B, Al, Al ₄ C ₃ ,
Examples include Al ₂ O _{3 and the} like. Examples of the binder include cellulosic binders such as methyl cellulose, carboxymethyl cellulose, and hydroxypropyl methyl cellulose, and polyvinyl alcohol. Examples of the plasticizer include glycerin and polyalkyl glycol polyethylene glycol. As a solvent,
Examples thereof include water, ethanol, toluene, methyl ethyl ketone and the like.

The mixture obtained by mixing molten silicon and silicon carbide is a mixture of molten silicon (about 1500 to 2500 ° C., preferably about 1600 to 2000 ° C.) and silicon carbide powder (average particle size of about 1 to 1000 μm, preferably about 1 to 1000 μm). Is about 1 to 100 μm) and is molded or filled in a mold of a desired shape (average particle size 1 to 100).
Silicon melted in about 0 μm, preferably about 1 to 100 μm (about 1500 to 2500 ° C., preferably 1
It can be obtained by pouring in (about 600 to 2000 ° C.).

The material obtained by impregnating silicon carbide with silicon is
For example, it can be obtained as follows.

First, silicon carbide (average particle size of 1 to 1000)
μm, preferably about 1 to 100 μm) powder,
If necessary, a sintering aid, a binder, a plasticizer, a solvent, etc. are added and kneaded, and the mixture is molded according to a conventional method and then in an inert gas such as nitrogen or argon at about 2000 to 3000 ° C., preferably 2500 to 3000. At a temperature of about ℃ 0.5 ~
A sintered body of silicon carbide is obtained by a method of firing for about 24 hours, preferably about 3 to 12 hours.

Alternatively, silicon carbide, silicon and carbon
If necessary, a sintering aid, a binder, a plasticizer, a solvent and the like are added and kneaded, and the mixture is molded according to a conventional method and then in an inert gas such as nitrogen or argon, at about 1500 to 3000 ° C., preferably 1600 to 2400. At a temperature of about ℃ 0.5 ~
A sintered body of silicon carbide can be obtained by a method of firing for about 24 hours, preferably about 5 to 24 hours. As the carbon, for example, fine powder of carbon having a particle size of about 1 to 100 μm can be used.

Next, the obtained sintered body of silicon carbide is
1500 to 2500 ° C, preferably 1600 to 20
It is immersed in molten silicon at a temperature of about 00 ° C. for about 0.5 to 24 hours, preferably for about 1 to 12 hours, and if necessary, a pressure of about 0.1 to 10 Pa is applied to immerse the silicon into silicon carbide. It can be obtained by impregnating a body.

In the mixture of the present invention, the ratio of silicon is 100% based on the total weight of silicon and silicon carbide, but it is 5 to 60% by weight in order to obtain excellent durability. % Is preferable, and about 5 to 35% by weight is more preferable.

The outer peripheral surface of the heater tube may be provided with fins for improving heat transfer. The shape of the fins is not particularly limited, and examples thereof include horizontal fins and vertical fins. The fin material is not particularly limited and may be different from the heater tube material, but normally,
Same as heater tube. The fins can be formed, for example, by using a mold in which unevenness is formed on the surface of the heater tube when the raw material is poured into the mold to form the heater tube. Alternatively, it may be formed by cutting the surface after manufacturing the heater tube.

The cap portion is not normally immersed in the liquid tank, but there is a risk that the cap portion may come into contact with the liquid in the liquid tank when the steam type throw-in heater is used. Since the liquid in the liquid tank may be an acid solution, a metal molded product having a corrosion resistant coating layer, a heat resistant and corrosion resistant resin molded product, an impervious carbon molded product, etc. are preferably used as the cap. These molded products can be manufactured by molding them into a desired shape according to a conventional method.

The metal serving as the substrate on which the corrosion resistant coating is applied is usually carbon steel, stainless steel, or the like. The corrosion-resistant coating layer can be formed by applying a material capable of imparting corrosion resistance, particularly acid resistance, to a metal formed into a cap shape according to a conventional method, followed by drying according to a commonly used method. Here, the corrosion resistance is, for example, 70 ° C.
Even if it is soaked in 15% hydrochloric acid for 168 hours (7 days), it does not have to be visually deteriorated. The anticorrosive coating layer may be provided on at least the outer surface of the cap.

Preferred examples of the coating material include fluororesins, epoxy resins and acid resistant paints. As the fluororesin, polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-ethylene copolymer (ETFE), ethylene trifluoride, vinylidene fluoride or the like can be used. Examples of the epoxy resin include bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, and alicyclic epoxy resin. The acid-resistant paint is not particularly limited as long as it can impart acid resistance to the substrate, and a paint containing a corrosion-resistant inorganic component such as ceramics or carbon is preferable. Specific examples of the acid-resistant paint include R-250 (manufactured by Okitsu), ES-300 and ES-200 (manufactured by Daishin Paint), 300 for Tetuzole flue (manufactured by Nippon Paint), Thermogin Chimuni 250 and Thermogin. Chimni 200 (manufactured by Tokyo Thermochemical), KP gamma ES250 and ES300
(Manufactured by Gamma Chemical) or the like can be used.

The anticorrosion coating layer can also be formed by spraying anticorrosion ceramics such as SiO ₂ or Al ₂ O ₃ on a substrate and sealing with a silicone resin according to a conventional method.

The thickness of the anticorrosion coating layer is not particularly limited as long as the anticorrosive property can be obtained according to the application, but it is usually about 10 to 1,000 μm, and about 50 to 500 μm. Is preferred.

Further, it is preferable to spray a metal such as nickel or stainless steel on the base material and subject it to a base treatment before providing the anticorrosion coating layer, because the adhesion is improved.

The heat and corrosion resistant resin is a resin having both heat resistance and corrosion resistance. For example, it has heat resistance up to about 200 ° C. and corrosion resistance, specifically, hydrochloric acid resistance, sulfuric acid resistance,
A resin having acid resistance such as chromium acid resistance is preferable. Corrosion resistance is, for example, 16% in 15% hydrochloric acid at 70 ° C.
Even if it is soaked for 8 hours (7 days), it is sufficient that it is not visually deteriorated.

As the heat and corrosion resistant resin, fluororesin (for example, fluororesin as exemplified above), polyphenylene sulfide (PPS), polyarylsulfone,
Polysulfone, polyether sulfone, polyamideimide, liquid crystal polyester, polyimide, thermoplastic polyimide, polyetherimide and polyetheretherketone (PEEK) are preferably exemplified, and among these, PP
S and PTFE are particularly preferred.

As the PPS, it is preferable to use a material which is reinforced by blending powdery or fibrous glass, filler such as carbon and fluorine (filler content is preferably 30 to 70% by weight). Specific examples of such materials include Trellina A604 and A400M X01.
(Manufactured by Toray), C140SG and C-160SL (manufactured by Idemitsu Petroleum Science), Fortron 1140A1 and 6165A.
4 (made of Polyplastics), Sustain CH-30
-12 (manufactured by Tosoh Corporation) and the like.

When the cap is a metal molded product with a corrosion resistant coating or a molded product made of a heat and corrosion resistant resin, it is usually attached to the heater tube using a flange, bolts and nuts. When installing, usually tighten the bolts on the cap side.

Since the throw-in heater of the present invention is of a steam type, it has a steam supply passage for introducing steam into the heater pipe. The steam supply path is connected to a boiler (steam supply device) that serves as a steam supply source, and is usually provided on the outer wall surface of the cap. The steam introduced into the space of the cap is introduced inside the heater tube. To be done. The material of the steam supply passage is usually the same material as the cap. The steam supply path is
When the material is metal, for example, a pipe can be welded and screwed to the outer wall surface of the cap to be formed. When the material of the steam supply path is resin, the introduction path can be formed by molding or shaving.

Further, the throw-in heater of the present invention is provided with a drain pipe for discharging liquefied water. That is, the steam introduced into the heater tube exchanges heat with the wall surface of the heater tube to become hot water, and flows down along the tube wall. The warm water collected at the lower end (closed end) of the heater pipe rises in the drain pipe due to the pressure of steam and is discharged to the outside. The shape of the drain pipe is not particularly limited as long as it can discharge the warm water collected at the lower end of the heater pipe to the outside, and can be appropriately selected from the commonly used shapes. The material of the drain pipe is not particularly limited, and a commonly used one may be used, and, for example, a pipe made of stainless steel or resin can be used.

The steam throw-in heater of the present invention can be preferably used for heating a liquid, more specifically for heating an acid solution such as hydrochloric acid or sulfuric acid for cleaning a metal plate.

The present invention also includes a steam-type heating device including the steam-type throw-in heater described above and a steam supplier. Such a steam type heating device may be the one that uses the steam type throw-in heater of the present invention as the heater portion to be immersed in the liquid tank in the commonly used steam type heating device. As an example of the steam type heating device of the present invention, in the device as shown in FIG. 1, the steam type throwing heater of the present invention is used as the steam type throwing heater A, and the steam generated in the steam supply passage (boiler 10) is depressurized. A device that can be introduced into the steam supply path of the heater through the valve 11 or the like is included.

[0038]

According to the present invention, it is possible to obtain a steam type throw-in heater which can be applied to a highly corrosive solution, is relatively easy to process and handle, and has an extremely excellent heat transfer property.

[0039]

EXAMPLES Examples will be shown below to further clarify the features of the present invention.

Examples 1 and 2 and Comparative Examples 1 and 2 Using the heater tubes made of the materials shown in Table 1 and the cap made of SUS304, steam type casting heaters having the structure shown in FIG. 2 were manufactured. As a mixed material of silicon and silicon carbide, which is the material for the heater tube, "Rikurite" (trade name, manufactured by Tokai High Temperature Industrial Co., Ltd .: a mixture of silicon carbide impregnated with silicon) is closed in a dome shape at one end according to a conventional method. Then, it is molded into a shape with multiple ends open, or silicon powder (average particle size of about 10 μm) and silicon carbide powder (average particle size of about 10 μm) are mixed at a weight ratio of 2: 1 and one end is a dome. Molded into a shape in which the mold is closed and multiple ends are open,
A sintered body obtained by heating at 1500 ° C. or higher for about 10 hours in an inert gas was used.

The length of the heater tube to be dipped is about 700.
mm × outer diameter of about 50 mm and wall thickness of about 5 mm.
The cap was provided with a steam supply passage made of the same material as the cap. A heating test was carried out to measure the time required to heat 100 liters of 15% hydrochloric acid from 20 ° C. to 70 ° C. using these heaters. The results are shown in Table 1 below.

[0042]

[Table 1]

Each of the products of the present invention (Example 1-2) had a shorter temperature rising time as compared with the conventional product (Comparative Example 1-2) and was excellent in heat transfer. Also, the product of the present invention is
Even when immersed in hydrochloric acid, 40% sulfuric acid, 60% nitric acid for 168 hours, no visual deterioration such as corrosion or deformation was observed.

[Brief description of drawings]

FIG. 1 is an overall view of a steam heating device using a steam throwing heater.

FIG. 2 is a longitudinal sectional view showing the structure of an example of the steam throw-in heater of the present invention.

FIG. 3 is a vertical sectional view showing the structure of another example of the steam throw-in heater of the present invention.

FIG. 4 is a vertical sectional view showing an example of a heater tube.

[Explanation of symbols]

1 heater tube 1'heater tube 1 "heater tube 2 cap 2'cap 3 Steam supply path 3'steam supply path 4 drain pipe 5 flange 6 bolts 7 nuts 8 pipes 9 Closure member 10 Boiler (steam feeder) 11 Pressure reducing valve 12 liquid tank 13 Steam trap 14 Steam flow meter 15 separator 16 pressure gauge 17 Strainer 18 Temperature control valve 19 Temperature sensor 20 stirrer A steam type throw-in heater

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Soichi Takamichi             4-1-2 Hirano-cho, Chuo-ku, Osaka-shi, Osaka Prefecture               Within Osaka Gas Co., Ltd. F-term (reference) 3L025 AB31

Claims (5)

[Claims] 1. A steam type throw-in heater having a heater tube having one end closed and a cap provided with a steam supply passage at the other end, and a drain tube, wherein the material of the heater tube is silicon. A steam-type throw-in heater, which is a mixture of slag and silicon carbide. 2. The steam type throw-in heater according to claim 1, wherein the mixture of silicon and silicon carbide is obtained by dispersing silicon carbide in silicon. 3. The steam type throw-in heater according to claim 2, wherein the mixture of silicon and silicon carbide in which silicon carbide is dispersed in silicon is a sintered body of silicon and silicon carbide. 4. The steam type throw-in heater according to claim 1, wherein the mixture of silicon and silicon carbide is obtained by impregnating silicon carbide with silicon. 5. A steam type heating device comprising the steam type throw-in heater according to any one of claims 1 to 4 and a steam type feeder.