JPS59161682A - Method of repairing industrial furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides industrial furnaces constructed of refractories, such as blast furnaces,
The present invention relates to a method for repairing hot blast ovens, coke ovens, converters, and other various industrial furnaces.

As is well known, the lifespan of industrial furnaces is greatly affected by the durability of the lining brick itself and the repair agent used.

Conventionally, as a method of repairing industrial furnaces, there has been a method of spraying powdered refractories on leaking joints and missing parts of bricks. As shown in Publication No. 15763, there are a dry method and a wet method.

Both of the above methods are carried out by spraying a repair agent supplied from a pressurized tank onto the furnace wall using a gun or nozzle. However, in all of the above methods, a large amount of water is added, so when the repair agent adhering to the furnace wall solidifies, water vapor is generated from the high temperature furnace wall side and receives internal pressure, which causes the repair agent to peel off from the furnace wall. This causes cracks to occur, which shortens the repair life and requires frequent repair work. Furthermore, when the repair agent is heated by using a furnace after repair, it contracts, creating minute gaps in the repaired area.

Further, the gas in the furnace enters into the minute gaps created by the contraction during heating and remains, and condenses when cooled. If this phenomenon is repeated, the gap will gradually expand, which will encourage the repair agent to peel off.

The present invention has been proposed in view of the above, and uses a Q-repair agent with low moisture content to improve adhesion at high temperatures, and expands at high temperatures to reliably close the repaired area. It is something.

To explain the present invention in detail below, the repair agent used in the method of the present invention includes an expanding agent that foams and expands in volume when heated, an adhesive, a fireproofing agent, and the purpose of preventing cracks and improving initial adhesion. This powder is a mixture of additives.

To repair the inside of a furnace using the above-mentioned repair agent, the above-mentioned granular repair agent is stored in a repair device that has a pressurized tank and a nozzle or blow gun connected to the pressurized tank. Then, while supplying water with the tip of a nozzle to the repair agent pumped from the pressurized tank, it is sprayed onto the leaking joints and missing parts of the bricks that are pasted inside the furnace.

Alternatively, water may be added to the granular repair agent in advance to form a mortar, and the liquid repair agent may be sprayed onto the repaired portion of the furnace or applied with a trowel.

Next, to explain each component of the above-mentioned repair agent, any expanding agent can be used as long as it foams and expands in volume when heated.
There are inorganic and organic types. Examples of inorganic expansion agents include vermiculite raw stone powder and nacre powder, and organic expansion agents include powders such as dinitrosopentamethylenetetramine, azodicarbonamide, and valatoluenesulfonyl hydrazide, each weighing 1 to 30% by weight. % mixing is preferred. If it is less than 1% by weight, no expansion effect during heating can be expected, and if it is more than 30% by weight, the mixing ratio of other components will be reduced.

On the other hand, as the above-mentioned adhesive, 7 liter powder, alkali silicate powder, etc. can be used, and 3 to 50 ton powder can be used.
% mixing is preferred.

Among the components of the above-mentioned adhesive, frit is generally used as a glaze for ceramics and enamel, and has a
When heated in the range of 00°C, it softens and becomes a uniform molten state. The components of these 7 liters include lead-based, boric acid-based, barium-based, and sodium-based ones, and when used as a component of a repair agent, they are preferably melted by heating, cooled and hardened, and then made into a fine powder. This frit is glass in a broad sense and has no melting point, so it softens over a wide temperature range and develops adhesive strength. Therefore, using a frit with an appropriate softening point is a precept for the repair agent of the method of the present invention.

Further, as the alkali silicate, sodium silicate, potassium silicate, etc. can be used, and as with the above-mentioned frit, these soften when heated and develop adhesive strength, so they are effective as adhesives in the method of the present invention. Since an alkali silicate salt which can be used as an O-adhesive expands in volume when heated, it functions both as an adhesive and as an expanding agent. Therefore, when using an alkali silicate, the addition of a swelling agent can be reduced or eliminated.

The mixing ratio of the above adhesive was set to 3 to 50% by weight.
If it is less than 3% by weight, it will have poor adhesion, and if it is more than 50% by weight, it will melt when softened and drip down when sprayed onto the furnace wall, making it impossible to reliably repair the repaired area.

In addition, as the above-mentioned fireproofing agent, an inorganic heat-resistant fine powder can be used, such as talc powder, magnetic powder, zircon powder, clay powder, silicon carbide powder, alumina powder, silica powder, 1 silica sand, etc. It is sufficient to mix up to 90% by weight.

This fireproofing agent is the meat of a repair agent! ＠To increase the amount and increase the operating temperature range of the adhesive (bonding temperature range) 1
．． It is mixed to make repair work easier, 20
If it is more than 90% by weight, the build-up amount will be insufficient, and if it is more than 90% by weight, it will be too much and the adhesive effect of the adhesive during heating will be reduced. If the particle size of this fireproofing agent is small, it may clog when mixed with water at the tip of the nozzle during repair, so
It is preferable that 20 to 60% by weight of about +n+n is contained.

Furthermore, additives to be mixed into the repair agent include anti-crank agents made of inorganic fibers, initial adhesion improvers, etc.
It is sufficient to mix 10% by weight. In addition, the crack preventive agent for inorganic fibers adapts to the expansion and contraction of the repair agent that becomes hot during the operation of industrial furnaces, so it prevents cracks from occurring due to the expansion and contraction of the repair agent. It is added to mutually disperse the powder composition and to prevent it from dripping in the heated state, and to prevent the generation of cracks, cracks, etc. caused by vibration G. As such a rank inhibitor, finely cut glass fibers, asbestos, rock wool, mineral wool, or synthetic inorganic fibers are preferable.

The repair agent used in the present invention contains each of the above-mentioned components in desired amounts, and the inner surface of an industrial furnace can be repaired using this repair agent when the industrial furnace is in operation. That is, a granular repair agent in which the above-mentioned components are sufficiently mixed is supplied to the repair device 2, and a pressurized tank is used to force-feed the repair agent in fixed amounts.
Water can be added to the tip of a nozzle or the like and sprayed onto repaired areas such as leaking joints in bricks and damaged areas of bricks.

Alternatively, water can be added to the repair agent in advance to form a mortar, and this repair agent can be sprayed or applied with a trowel to the repaired area in the furnace. In this case, 10 to 40 g of water may be added to the powder repair agent and mixed thoroughly. When the granular repair agent is mixed with water to form a mortar, the viscosity modifier can be mixed in advance with the granular repair agent, or the viscosity modifier can be added to the water at the time of mixing. This viscosity modifier is used to adjust the viscosity of the mortar-like repair agent, and water-soluble adhesives such as resin emulsion, methyl cellulose, gum arabic, and sodium alginate can be used. It is desirable to add in a range of 20% by weight.

Among the above-mentioned viscosity modifiers, those that decompose during heating to generate carbon dioxide gas and water vapor, such as methylcellulose and carboxymethylcellulose, can reduce the need for adding an expanding agent.

The repair agent sprayed onto the repaired area on the inner surface of the furnace as described above immediately evaporates moisture due to the high temperature inside the furnace, softens the adhesive, and causes the particles contained inside to interact with each other to form the repaired area. It adheres strongly and will not drip or peel off. Since the expanding agent foams and expands in volume when heated, it can form a droplet-like shape in the repaired area and can fill voids due to the volumetric expansion of the expanding agent. Therefore, the repaired part after repair with the expansion agent is less likely to crack or crack, and is less likely to peel off.

Therefore, according to the non-invention, it is effective for a long time and the repair life is significantly extended.Compared to the conventional service life, which lasts from several weeks to three months, it is several times more effective and requires fewer repairs. Not only that, but the furnace wall does not develop cracks or cracks for a long time, so there is no wastage of thermal energy.

In addition, in the past, the adhesive strength of the repair agent was weak, so when repairing it, even healthy bricks would peel off and the defective area would expand, but with the present invention, the adhesive strength is high even at high temperatures, so the defective area can be easily removed. It can be repaired immediately by spraying, and since the healthy bricks do not peel off, there is no need to repair the defective parts with mortar, and since the healthy bricks are not damaged, the life of the furnace is sufficiently extended. Moreover, since repairs can be made while the furnace is in operation, there is no need to stop the furnace to cool it down as in the conventional case, and it is possible to prevent operational losses, thermal energy losses, etc. due to the furnace's shutdown.

The present invention will be explained in detail below.

Repair agent of the present invention (1) Sodium silicate (No. 3 powder) 15% by weight Lead-free 7 liters (softening temperature 770°C) 5% by weight (X'M-233 manufactured by Nippon Frit Co., Ltd.) No. 3 silica sand
1o Weight section No. 5 silica sand
3o Weight range clay powder 27
Heavy M rock wool 11 Weight width glass fiber 0.5 weight width Methyl cellulose 1.5 weight Repair agent of the present invention (2) Dinitrosopentamethylenetetramine 3 Weight width frit (softening temperature 590'C) 20 71
1 can J (PN-5400, manufactured by Nippon Frit Co., Ltd.)
No. 3 silica sand 1o Weight class No. 8 silica sand 45% by weight Clay powder
16 Weight width glass fiber
1% by weight asbestos
5 Weight width Repair agent of the present invention (3) Vermiculite raw stone powder 15 Weight % Sodium silicate (No. 3 powder) 20 Weight width Talc
25% by weight silicon carbide
40 Weight width Repair agent of the present invention (4) Pearlite powder 30 Weight width frit (softening temperature 770°C) 7.5 weight width (XM-233 manufactured by Nippon Frit Co., Ltd.) Alumina powder
1o Heavy M section No. 3 silica sand 22
．． 5 weight ratio No. 5 silica sand 25 weight% glass fiber 0.5 weight ratio slag cotton 4.5 weight width Repair agent of the present invention (5) Vermiculite rough powder 10 weight width frit (softening temperature 770°C) 2.5 weight width (xM-233 manufactured by Nippon Frit Co., Ltd.) Sodium silicate (No. 3 powder) 25% by weight Silicon carbide 20 Weight range Talc 20 Weight range No. 4 silica sand
20 Weight section No. 6 silica sand
15 Weight width glass fiber
1 Weight engagement cotton
9 Repair agent of weight range comparison example (1) Commercially available high alumina repair agent At20.55-60 parts 5i02 40-45 parts Fg
203 o, s ~1.2 parts Comparative repair agent (2) Commercially available clay type repair agent At20342-45 parts 5402 52-55 parts FC
2031, 0 to 1.2 parts Example 1 Left and right chamotte bricks/ as shown in the drawing.

Another chamotte brick unit was placed above between 1 and 2, and a mortar-like repair agent 3 with a thickness of 5 mm was interposed between 7 parts 2 of each brick. Mortar-like repair agent 3 had a weight ratio of repair agent to water of 5:1, and the repair agent of the 5 types of the present invention and two types of repair agents of comparative examples were prepared separately. After creation, leave it at room temperature for 24 hours to harden and adhere, then heat it in a heating oven at 1150℃.
The mixture was heated for 5 hours and then cooled to room temperature. Thereafter, a load was applied from above to the central chamotte brick unit as shown by the arrow in the drawing using a universal testing machine, and the maximum load at which the adhesive surface of the repair agent broke was defined as the adhesive strength.

The adhesive strengths of the five types of repair agents of the present invention and the two types of repair agents of comparative examples were as shown in the table below.

Example 2 Repair by spraying the pre-repair 'j (1) + (4) of the present invention and the comparative repair agents (1) and (2) on leaky joints and defective parts of bricks on the inner surface of a coke oven. Repair work was carried out using this method, and the service life was measured. As a result, the comparative repair agents peeled off after 1 to 2 months and had to be repaired again, but the repair agent (1) of the present invention.

In all cases (4), there was almost no peeling even after 6 months had passed, and the repair life was significantly extended.

[Brief explanation of the drawing]

The drawings are schematic views of the first embodiment of the present invention. Patent applicant Taipo Liang Co., Ltd. Patent applicant Nippon Kokan Co., Ltd. 1/' Valve 81 “lit!iQE,
, alternating lights).

Claims (3)

[Claims] (1) In the industry where a repair agent containing an expanding agent that foams when heated to high temperatures, an adhesive that melts and has adhesive properties when heated to high temperatures, a fireproofing agent, and an additive is used in a high-temperature state. The adhesive is supplied to the repaired area inside the furnace, and the repair agent is firmly attached to the repaired area by softening the adhesive, and the repair agent is foamed by an expanding agent to occlude the repair area. How to repair industrial furnaces. (2) The method for repairing an industrial furnace according to claim (1), wherein the expanding agent is an inorganic or organic powder. (3) The adhesive is frit powder or alkali silicate powder.
A method for repairing an industrial furnace according to claim (1), which is a method for repairing an industrial furnace.