JPH08178253A - Lining flue - Google Patents

Abstract

(57) [Summary] [Structure] A lining flue in which a silicone rubber sheet is sandwiched between the inner wall of the flue and the sheet fixing member and is in close contact. [Effect] It is possible to satisfactorily prevent corrosion and deterioration of the inner wall of the flue, easily repair and replace the lining, and even if the inner wall expands and contracts due to temperature changes, the protective film will crack and peel. Never.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a lining flue having an inner wall provided with a lining material.

[0002]

2. Description of the Related Art Generally, exhaust gas from a boiler that uses heavy oil as a fuel is diffused into the atmosphere through a flue after absorbing and removing sulfur dioxide by a desulfurizer. It contains sulfurous acid gas, nitrous acid gas, etc., which cannot be removed even from the exhaust gas, and further contains fine ash content produced by the combustion of water and heavy oils. As heavy oils, heavy oils having a large sulfur content and low-quality oils having a large ash content during combustion are often used due to the recent energy situation. Since such heavy oils generate high-temperature acidic gas when burned, the inner wall of the iron flue is severely corroded and deteriorated, and the inner wall iron plate must be repaired and replaced at regular intervals.

The ash generated during combustion adheres to the inner wall and enters the gaps in the expansion joints that connect the flues and absorb the thermal expansion and contraction of the flues, so the ash removal work during regular repairs is extremely difficult. Become complicated. Conventionally, as a method for repairing and protecting the inner wall of the flue, there is a method of lining the wall surface by using an acid-resistant metal plate such as stainless steel or an FRP plate. However, this method has a drawback in that it is difficult to carry in a metal plate or FRP plate having a large area from the flue port to the inside, and therefore the flue outer plate, the heat insulating heat insulating material and the like must be removed before construction.

Japanese Patent Publication No. 3-20644 discloses a method of applying an acid / heat resistant room temperature curable liquid silicone rubber to the inner wall of a flue and curing it to form a protective film. . However, the protective film of the silicone rubber formed in this way, because the inner wall expands and contracts due to the temperature change when the boiler is operating or stopped, the protective film that adheres to the inner wall cannot follow the expansion and contraction, and the material of the film is Although it is not deteriorated, it has a defect that the film cracks or peels off.

[0005]

The object of the present invention is to prevent corrosion and deterioration of the inner wall of the flue, and to easily repair and replace the lining, and to expand and contract the inner wall due to temperature changes. Even so, it is to provide a lining flue without cracking or peeling of the protective coating.

[0006]

The present invention is a lining flue in which a silicone rubber sheet is sandwiched between an inner wall of the flue and a sheet fixing member and closely adhered thereto. Hereinafter, the present invention will be described in detail. The silicone rubber sheet used in the present invention is not particularly limited, and can be obtained, for example, by molding silicone rubber into a sheet with an extruder or the like, or by pouring a silicone resin into a sheet mold and curing it.

The silicone rubber used in the present invention is not particularly limited as long as it has excellent properties such as heat resistance, acid resistance, water resistance and flexibility. For example, either a heat vulcanization type or a room temperature curing type can be used. Silicone rubber can also be used. Specifically, for example, millable types such as organic peroxide cross-linking type and addition cross-linking type; deacetic acid condensation cross-linking type, deoxime condensation cross-linking type, dealcohol condensation cross-linking type, de-acetone condensation cross-linking type, de-hydroxy amine condensation A liquid rubber type such as a crosslinking type or an addition reaction crosslinking type can be used. Among these, organic peroxide crosslinkable millable type and deoxime condensation crosslinkable liquid rubber type are preferable.

The silicone rubber sheet preferably contains heat resistant fibers and metal wires. As the heat resistant fiber, for example,
Inorganic fibers such as glass fibers, metal fibers and ceramic fibers;
Organic fibers such as polyimide fibers, aromatic polyimide fibers, polyimidazole fibers, and polyamideimide fibers can be used. These heat resistant fibers and metal wires may be cut into short pieces, woven fabrics such as nets and cloths, mixed with silicone rubber, or sandwiched between silicone rubber sheets in a sandwich form. The thickness of the silicone rubber sheet is 1 to 10 mm, preferably 2 to 6 mm.

The sheet fixing member used in the present invention is not particularly limited as long as it can be fixed so that the silicone rubber sheet is sandwiched between the inner wall of the flue and the inner wall of the flue. To fix the silicone rubber sheet 1 at the peripheral edge of the sheet, as shown in FIGS. 1 and 4, to fix the silicone rubber sheet 1 at opposite edges of the sheet, and as shown in FIG. Examples thereof include those in which the rubber sheet 1 is fixed at the adjacent edges of the sheet, those in which the silicone rubber sheet 1 is fixed at the central portion of the sheet, and the like.

The shape of the sheet fixing member 2 used in the present invention is not particularly limited as long as the silicone rubber sheet 1 can be sandwiched between the inner wall of the flue and it can be appropriately designed according to the cross-sectional shape of the flue. For example, a frame shape as shown in FIG. 2, a rod shape as shown in FIG. 3, a cylindrical shape as shown in FIG. Also, these may be used in combination. Among them, as shown in FIG.
It is a fixing member that combines a frame type and a rod type. The material for the seat fixing member may be any material that can withstand the atmosphere of the flue, preferably a temperature of 160 ° C, a sulfurous acid gas concentration of 3000.
A material that can withstand ppm for a long time is preferable. Specific examples include a stainless steel plate, a heat resistant epoxy FRP plate, a phenol FRP plate, a carbon FRP plate and the like.

There is no particular limitation on the method of sandwiching the silicone rubber sheet on the inner wall of the flue with the sheet fixing member.
For example, a bolt hole is provided on the flue wall surface, and a method of sandwiching it with an anchor bolt through a sheet fixing member provided with a through hole to correspond to this, a stud bolt welded to the flue wall surface It is possible to cite a method of sandwiching with a nut via a sheet fixing member having a through hole. If the flue wall surface is strong enough, it is preferable to use stud bolts to pinch it. After sandwiching the silicone rubber sheet with the sheet fixing member so as to cover the inner wall of the flue, the seam of the resulting silicone rubber sheet is filled with liquid silicone rubber or adhesive silicone rubber of the same type and bonded or sealed. Preferably.

As described above, in the method of lining the inner wall of the flue using the silicone rubber sheet, the preformed sheet can be easily carried in from the working manhole in a state of being cut into a proper length and rolled up. It has the merit of not requiring large-scale construction such as dismantling a part of the flue like other construction methods. In addition, this lining method has a great merit that even when a flue is newly constructed, it can sufficiently cope with a flue iron plate that has advanced corrosion deterioration to some extent even during a limited period of regular inspection / repair of boiler equipment,
It can be used not only for flues but also for wall protection at construction sites, wall protection at work sites where molten sparks are scattered at steelworks, and shielding films for ensuring safety.

[0013]

EXAMPLES The present invention will be described more specifically by showing examples and comparative examples. Preparation Example 1 of Silicone Rubber Sheet (Millable Type ) 100 parts by weight of dimethylpolysiloxane having a vinyl group content of 0.015 mol% (polymerization degree of about 8,000) and fumed silica 40
8 parts by weight of dimethylpolysiloxane containing OH groups at both ends as a wetter (viscosity at 25 ° C .: viscosity 20 cSt), (CH ₃ ) ₃ SiO _1/2 unit 1 mol, and SiO ₂ unit 1
A silicone rubber composition consisting of 10 parts by weight of a copolymerized silicone resin consisting of mol was prepared. 0.6 parts by weight of 2,4-dichlorobenzoyl peroxide as a curing catalyst was added to 100 parts by weight of this composition, and the mixture was kneaded uniformly with a roll. Then, this was continuously formed into a sheet by an extruder and crosslinked by a normal pressure hot air vulcanization method to obtain a silicone rubber sheet (width 1 m × thickness 3 mm × length 10 m 2). The heating condition was 300 ° C./2 minutes. Hereinafter, this sheet is referred to as a prototype sheet A.

Preparation Example 2 of Silicone Rubber Sheet
Beam-type) both molecular chain terminals viscosity at been dimethylpolysiloxane oil (25 ° C. blocked with OH groups: 5,000 cSt) 100 parts by weight, 10 parts by weight fumed silica, and dioctyltin dibutyltin
Add 0.1 parts by weight to a gate mixer, 100 ° C, -650
Stirring heat treatment was performed for 2 hours under the condition of mmHg. Then
6.0 parts by weight of methyltris (methylethylketoxime) silane was added thereto while being careful not to mix water, and the mixture was stirred and mixed for 15 minutes. The obtained liquid composition was poured into a metal mold and allowed to stand at 25 ° C. for 2 days to obtain a sheet-shaped cured product having a width of 1 m × a thickness of 2 mm × a length of 2 m. Hereinafter, this sheet is referred to as a prototype sheet B.

Preparation Example 3 of Silicone Rubber Sheet (Reinforcement
Type) On a silicone sheet obtained in the same manner as in Production Example 2,
A sheet and a glass cloth of the same size were overlaid.
Then, the same composition was poured and cured so as to have a thickness of 2 mm, and a 4 mm-thick silicone sheet was obtained by sandwiching glass cloth in a sandwich form. Less than,
This sheet is called trial sheet C.

Examples 1 to 3 The exhaust gas temperature was 150 ° C., the average sulfur dioxide gas concentration was 1500 ppm, and the maximum exhaust gas velocity was 20 m / sec.
A 1m x 1m wide SPC iron plate is adhered and covered with the above prototype sheet (silicone rubber sheet 1) cut to the same size as the iron plate. As shown in Fig. 1, both edges of the silicone rubber sheet 1 are covered. Iron sheet fixing member 2 (width 5 cm x thickness 4 m
m × length 1 m) and fixed. The flue inner wall 4 and the fixing member 2 are fixed to each other by arranging the stud bolts 5 (6 mm φ) welded to the flue inner wall 4 at intervals of 25 cm and the fixing member 2 having holes 3 at positions corresponding thereto. Then, it was fixed with a nut 6. After lining the trial sheets A, B, and C in this manner, the following items were inspected at the time of regular flue repair 1 and 2 years later. It should be noted that the one lined with the trial sheet A is referred to as Example 1, the one lined with the trial sheet B is referred to as Example 2, and the trial sheet C is used.
Example 3 was lined with. The results are shown in Table 1.

(Inspection item) Appearance: The surface condition was visually observed. Hardness, tensile strength and elongation: Measured according to JIS K 6301. For the hardness, an A-type spring hardness tester was used. SPC iron plate corrosion: The surface condition was visually observed, and those with no change were indicated by ◯, those with a discolored surface were indicated by Δ, those in which corrosion was observed were indicated by x, and those in which corrosion was noticed were indicated by xx. Ash removal: The ease of ash removal was determined.

COMPARATIVE EXAMPLE 1 An SPC iron plate was fixed to the inner wall of the flue, and an inspection was conducted at the time of regular flue repair as in Examples 1-3. The results are shown in Table 1.

COMPARATIVE EXAMPLE 2 A part of the iron plate on the inner wall of the flue was cleaned, and the above-mentioned Preparation Example 2 was placed thereon.
Approximately 4 m of the one-component liquid silicone rubber composition used in
It was applied to an iron plate with a thickness of m and left to cure at room temperature. The inspection was conducted at the time of regular flue repair as in Examples 1-3. The results are shown in Table 1.

[0020]

[Table 1]

Evaluation of Inspection Prototype sheets A and C had a sufficient rubber elasticity even after two years had passed. The sheet rubber elasticity of the trial sheet B was the same as that of the trial sheet C, and the surface state of the coated SPC iron plate was slightly discolored, but no remarkable progress of corrosion was observed. The SPC iron plate of Comparative Example 1 was severely corroded, and it was difficult to remove the ash attached to the surface. Further, in Comparative Example 2, although deterioration of the rubber substance itself of the silicone rubber lining layer was not recognized after one year, cracks occurred in the lining layer, and about half of the lining area was peeled off to function as a protective layer. Didn't.

[0022]

INDUSTRIAL APPLICABILITY The present invention satisfactorily prevents the corrosion and deterioration of the inner wall of the flue, allows the lining to be easily repaired and replaced, and protects the inner wall even if the inner wall expands or contracts due to temperature changes. There is no cracking or peeling.

[Brief description of drawings]

FIG. 1 is a conceptual diagram illustrating a mode in which a silicone rubber sheet is sandwiched between sheet fixing members.

FIG. 2 is a conceptual diagram illustrating a mode in which a silicone rubber sheet is sandwiched between sheet fixing members.

FIG. 3 is a conceptual diagram illustrating a mode in which a silicone rubber sheet is sandwiched between sheet fixing members.

FIG. 4 is a conceptual diagram illustrating a mode in which a silicone rubber sheet is sandwiched between sheet fixing members.

FIG. 5 is a conceptual diagram illustrating a mode in which a silicone rubber sheet is sandwiched between sheet fixing members.

[Explanation of symbols]

 1 ... Silicone rubber sheet 2 ... Sheet fixing member 3 ... Hole 4 ... Flue inner wall

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Keisuke Imai, Izumi Keisuke, Gunma Prefecture, Usui-gun, Gunma Prefecture, No. 1 Hitomi 10 Shinetsu Chemical Industry Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Minoru Nonaka Shibaura, Minato-ku, Tokyo Chome 2-3 Shimizu Construction Co., Ltd.

Claims (1)

[Claims] 1. A lining flue comprising a silicone rubber sheet sandwiched between an inner wall of the flue and a sheet fixing member so as to be in close contact with each other.