Configuration of refractory materials for heating furnace and construction method of refractory plastic for heating furnace

Principles and design concepts underlying the configuration of refractory materials

(1) Plastic has high refractoriness and high flexural strength, and its function is to make direct contact with the flame in the furnace and resist the scouring of furnace gas. In order to reduce the construction cost, and according to the working temperature difference of each part of the furnace body, the design has selected a number of grades of plastic.

(2) Lightweight brick thermal conductivity between the plastic and fiber refractory materials, its working position is also between the two. But because there are many parts of the furnace body plastic and fiber refractory materials in direct contact, because the calculation of the furnace body heat dissipation, based on the minimum thermal conductivity of the refractory materials, so you can ignore its chemical composition and physical properties.

(3) Because of the plastic thermal conductivity is large, in order to reduce the energy loss of the heating furnace, improve the efficiency of energy use, so the design of the thermal conductivity is very low fiber refractory materials used in conjunction with it. Compared with plastic, fiber refractories can be regarded as 0, that is, adiabatic materials.

(4) According to the special characteristics of the furnace parts and the convenience of construction, the use of ceramic fiber boards in the furnace wall parts, the use of ceramic fiber blankets in the furnace roof parts; due to the limited space on the roof of the furnace, so the use of ceramic fiber blankets with a thin but lower thermal conductivity.

Comprehensive table can be seen, the bottom of the furnace did not use plastic, that is, the furnace body insulation only need to consider the furnace wall and roof, and the roof of the refractory thickness of the smallest, and the furnace body of each section of the plastic grade is different, which will be later chapters in the search for thermal insulation benchmarks to lay the foundation.

Performance parameters of refractory plastics for heating furnaces

(1) Air compressor: outlet pressure 0.7MPa, flow rate 9m3/min. quantity: 2 sets. Linking method: parallel connection.

(2) Air hammer: working air pressure is 0.49MPa, impact frequency is above 10Hz. Quantity: 20 units.

(3) A number of 20×200×2000mm wooden boards.

(4) Several scraping rakes, steel plate knives, hammers, steel braziers, etc.

Construction Method

(1) Support template according to the specific conditions of the site as far as possible to make the template can be moved, which can save the template. In the fixed template placed in the plastic mold brick, scraping after the furnace wall or furnace top continue to place plastic mold brick, mold brick placed evenly between the two adjacent layers staggered arrangement, each layer can only put a single layer.

(2) Pounding to start from the joints between the billet, the hammer head moving along the forward direction, it is appropriate to overlap 2/3, line to line overlap 1/2, require repeated pounding more than three times, the total compression is greater than the thickness of each billet of 1/3. pounding strength is uniform, the air hammer is perpendicular to the furnace cross-section. Each operator is responsible for the length of the furnace body does not exceed 1.5 meters. When the work area is large, by more than one person to cooperate to complete.

(3) Scraping each layer, should be scraped before the plastic hardens, immediately put down a layer of plastic, then pounding, so that the two layers can make a better combination. After playing the mold, the furnace wall or roof plastic must be scraped before hardening, its role is to make the furnace surface rough, to facilitate the dissipation of moisture.

(4) Riveted brick construction first prepared mold brick and hard wood, mold brick upper surface processing into a flat surface, the remaining three sides should be strictly in accordance with the riveted brick drawing size processing, the number of mold bricks prepared for the design of the number of 1%, in the correct position to hang a good mold brick, and pounding mold brick, so that it is embedded in the plastic, the formation of clearly visible brick teeth in the plastic traces. Remove the mold brick, replace the riveted brick gently into the material, so that the plastic and riveted brick between the full, close combination, and then use a wooden wedge to fix the riveted brick, and then continue to put into the blank, and then pounding.

(5) Cut expansion line plastic liner heated surface expansion line should be cut according to the design position, its role is to make the furnace body regular stress release, to avoid irregular damage to the furnace body. Two expansion line spacing 1.2 ~ 1.5 m, each expansion line and the center line between the two riveted brick coincides with the depth of about 30 ~ 50 mm. the operation in the furnace body after scraping.

(6) Tie ventilation holes should be in the scraping of the plastic lining of the heated surface (furnace roof or wall) to play ventilation holes, the depth should be up to 2/3 of the lining thickness, but can not penetrate the diameter of 2 ~ 3mm, the spacing between the ventilation holes 150mm, the direction of the arbitrariness. Throughout the above construction methods can be seen, under the action of pounding, the furnace body (roof, wall) in the plastic, fiber refractory materials are tightly combined, has formed a whole, which for the later chapters of the thermal conductivity calculations laid the foundation.

Construction Precautions

(1) During or after construction, the plastic masonry is not allowed to come into contact with water, and winter construction should pay attention to frost protection.

(2) Between construction, the pounding body should be cut straight, that is, the plastic pounding surface perpendicular to the furnace shell, covered with plastic film and wrapped to prevent moisture dissipation. If the pounding continues, the dried surface should be cut off and scraped.

(3) When constructing the pouring material at the contact place with plasticizable, waterproof the plasticizable well.

Reheating Furnace