Refractory Fiber Products Characteristics And Superiority
Refractory fiber products can also be called ceramic fiber, is a fibrous insulation refractory, corrosion-resistant materials. Developed in 1941, it and fiber, can be used for paper, wire, rope, belt and other items.
The refractory fiber has become the preferred material for refractory, heat preservation, heat insulation, sound insulation and fireproofing, which has replaced brick structure and castable with high temperature (1000 ~ 1400 ℃), vibration resistance, heat absorption, sound absorption and light weight. In metallurgy, petroleum, chemical, machinery, construction and other industries are widely used. The traditional refractory fiber construction technology mainly refers to the construction technology of refractory fiber products. The use of paste, stitching and other technologies and processes for construction, construction difficult, slow, difficult quality control, seams and more, poor overall, the operation of workers labor intensity, the environment is bad. Refractory fiber spraying technology is a new technology and technology of fiber construction mechanization. The technology is the use of fiber spray gun, the binder through the diaphragm pump evenly sprayed into the fiber, both in the gun outlet mixed spray directly to the work surface, the formation of three-dimensional network-like product structure. To overcome the shortcomings of the traditional construction technology, is conducive to improving the thermal efficiency of industrial furnace.
Heat-resistant refractory products made of refractory fiber as the main raw material are known as refractory fiber products. Refractory fibers are divided into amorphous (vitreous) and polycrystalline (crystalline) two categories: amorphous refractory fibers, including aluminum silicate, high purity aluminum silicate, chromium and aluminum silicate Refractory fibers; Polycrystalline refractory fibers include mullite fibers, alumina fibers, zirconia fibers. The maximum temperature of the refractory fiber products is different depending on the product fiber type and the furnace atmosphere, generally at (1100 ~ 1500) ℃.
Applicable to high temperature refractory binder variety, performance varies. According to the chemical properties of the binder is divided into inorganic binders and organic binders. The inorganic binders are mainly silicates, aluminates, phosphates, sulfates, chlorides and sols; organic binders include natural organic and organic compounds. High temperature binders used in refractory fiber spraying are generally sodium silicate.
Rock wool in the insulation, insulation has a good performance, cheap, working temperature between (-268 ~ 700) ℃. Can be used for continuous working temperature of 600 ℃ below the furnace and pipe lining to heat insulation.
The thermal conductivity of aluminum silicate is the lowest in the condition of (250 ~ 300) kg / m3. Standard ordinary aluminum silicate fiber, high alumina fiber spray were used for the working temperature of 1000 ℃, 1200 ℃ below the thermal equipment, for fire, heat insulation, insulation layer, high aluminum and the wrong fiber and the wrong fiber spray Used in 1300 ℃ high temperature furnace.
Commonly used aluminum silicate series of binders are thermosetting binders. In the agreed operating temperature range, the binder composition, the ratio should help to form a bond chain and network structure, both rapid promotion of coagulation, curing does not shrink, but also with uniformity, dispersion, activity, taking into account the initial strengthening Degree and hot sintering properties. The heat resistance of the thermosetting binder is not less than 1750 ° C and the viscosity (6.0 to 8.0) x 10-3 Pa · s.
1. Application scope
Refractory fiber products have many advantages, but its strength and refractory bricks, high-strength castables compared to a large gap, so the refractory fiber products for direct contact with the lining, no granule gas flow and gas flow rate ≤ 20m / s ( If the coating surface coating can enhance the anti-air flow ability) of the various industrial furnace refractory lining and composite lining of the insulation layer. Collected from China Asset Management Network. In addition, through the selection of fiber raw materials, towers, cans, containers and other external insulation can also be used fiber products. Spraying technology is the improvement and progress of refractory fiber construction technology, construction speed, good quality. The structure suitable for use with refractory fiber products is also suitable for the use of spray technology.
2. Characteristics and superiority
At present, most of the domestic furnace furnace wall is still using brick structure, the drawback is the ignition temperature, the heat storage capacity, heating rate is slow, heat consumption increased; poor insulation effect, heat loss, poor working environment; , Not suitable for automatic control of combustion.
For the lining of the composite structure, the lining material from refractory brick to castable to the development of lightweight fiber mats, blankets, blocks, etc., of course, to a certain extent, improve the furnace technical performance indicators, but the construction of fiber products behind the construction quality It is difficult to guarantee that the life of the lining is greatly affected. The main drawback is the manpower into the large, slow construction, construction quality is difficult to control; fiber products through straight seam, tight sealing, easy channeling fire; spherical and shaped structure is difficult to construction, repair and repair difficult.
For the furnace and other industrial lining, the fiber coating material using high-quality fiber raw cotton, high-performance fiber series binder as raw material, in the one-time overall spraying process to form a network structure, compared with other construction methods, has the following advantages:
(1) a one-time spray obtained by the seams without seams, effectively avoiding the fiber products at high temperature directional shrinkage, eliminating the blow-by gas, dew point corrosion on the furnace shell, anchor nail damage, strengthen the seal, Shun fire performance, improve the thermal efficiency of industrial furnaces.
(2) fiber spraying technology can reduce the complex surface, such as the spherical, corners, doors and smoke pipe joints and other parts of the overall construction of the difficulty of anchoring, improved the shape of the joints at the sealing performance. The lining is firm, uniform and smooth, with strong corrosion resistance. Spraying construction is convenient, flexible, anchor nail with less, and all buried in the fiber furnace lining, effectively prevent the nail head burning, to avoid heat short circuit.
(3) Sprayed fiber linings have a lower thermal conductivity than flat felt and blankets, have better thermal strength than stand-up folding blocks. The anchors are buried in the spray coating without direct heat transfer, saving 15% to 30% The
(4) Spray coating economy is fair, according to the industrial furnace conditions, the use of a variety of fiber layered composite spray, is conducive to the realization of composite heat transfer mechanism of the temperature gradient distribution, reduce the overall cost of lining materials.
(5) refractory fiber spraying speed than the conventional construction method of 4.5 times, especially for the repair project has the upper hand. Coating structure is a flexible material, spray construction can be put into use after completion, reducing the oven time of nearly 4/5.
1. The ambient temperature during the construction of the lining shall not be lower than 5 ° C during the construction of the oven. The rainy season shall be carried out in the rainy season. All the holes and the burner holes of the heating furnace shall be sealed with cork or kraft paper.
2. Steel derusting standards should reach St3 level. Anchor nail welding root should be full of welding, no bite, vertical deviation ≤ 5mm, height error ± 2mm, spacing error ± 5mm.
3. According to the thickness of the spray lining layer of spray refractory fiber, hanging between the layers of stainless steel mesh, the lining should be completely covered anchor bolts, and the inner surface and anchoring nail should be the top (25 ~ 30) mm interval, spraying process is strictly prohibited Elastic material.