Main methods for hot repair of coke ovens

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Generally, the methods for hot repair of coke ovens include shot blasting and patching; local reconstruction is only employed when the oven is severely damaged (such as collapse of the furnace head or high-temperature incidents in the regenerator). When the coke oven masonry has relatively fine cracks (mainly in the furnace wall and furnace head areas of the carbonization chamber), or when the wall surfaces have shallow depressions, the spray repair method is advisable. When applying spray repair, the following points should be noted: (1) Before spraying the repair material, use a shovel to remove graphite and other debris from the surface to be repaired, and blow it clean with compressed air at a pressure of 2.5–3 kilograms per square centimeter, so that the repair material can adhere more easily. (2) When dealing with individual defects, spray repair should employ different nozzles, spray angles, and air pressure depending on the condition of the defect. For example, when filling gaps with spray application, use a nozzle with a small spraying area and an air pressure of 2.5–3 kilograms per square centimeter; aim the nozzle at the gap so that the mortar is sprayed directly into it as much as possible ； When spraying the furnace walls of the carbonization chamber, a nozzle with a large spraying area should be used, with the nozzle tip at an angle of 30 degrees to the wall of the carbonization chamber, and a wind pressure of 2.0–2.5 kilograms/cm2. (3) During spraying, the nozzle should be kept 200-300 millimeters away from the wall, and the spraying rod should move evenly. (4) During spray repair, the thickness of each layer applied should not exceed 5 millimeters; the next layer should be applied only after the previous one has dried, and the total thickness of all layers applied together should not exceed 15 millimeters. (5) The slurry used for spraying should be thoroughly mixed and filtered before being fed into the spraying machine; it is not allowed for the slurry to remain in the spraying machine for too long, especially phosphate slurry. When there are large cracks in the coke oven masonry and deep defects on the walls, patching should be used. When applying the patch, the following points should be noted: (1) The wall surface must be cleaned thoroughly before applying the patch, and then a layer of thin slurry should be sprayed on it. If the gap is clean, it can be filled directly. (2) When applying the mud with a trowel, the mud should be of appropriate consistency; press it firmly against the area to be repaired, wait for a moment so that the mud adheres to the bricks, and then push or pull to complete the troweling action. Apply it until it is slightly recessed from the wall surface. Once the mud is dry, apply a thin layer of slurry using a sprayer. (3) For larger defects or molten pits, they should be repaired in several stages; after each repair, wait until the mud dries before applying the next layer. Whether it is spray patching or troweling, after the treatment is completed, the bottom of the carbonization chamber must be cleaned and the furnace door closed. Coal can be loaded for production only after the slurry has dried out and reached a temperature close to that of the furnace walls. This post was last edited by ryn on 2009-3-26 17:38]