Is the furnace roof cover corroded?
Thread Content
The boiling furnace in our company releases air from the side, and its roof insulation is made of high-temperature concrete. Due to corrosion and perforations, it needs to be replaced every year. Could it be that the original layer of insulating perlite powder caused the temperature to drop too low, leading to the formation of condensation acid that caused corrosion? I’m wondering if anyone has any methods or experience in dealing with this issue.
Are there claws embedded in high-temperature concrete?
Is it a gripping nail connected to the cover plate? If so, then it’s not there, as high-temperature concrete is poured first and then the cover plate is placed on top. Is the moderator suspecting air leakage? There is indeed air leakage.
Try pouring in sections using phosphate cement
Suggestions: 1. Prepare the top cover properly and reinforce it with a frame to prevent deformation； 2. Weld grab nails to the top cover, and pour high-temperature resistant concrete ； 3. Lift the top cover (including the high-temperature resistant concrete lining), weld the outer shell, and complete the inner lining.
If it gets damaged again next year, follow the methods suggested by the moderators. Thank you all.
Originally, a spherical arch made of refractory bricks was used; later, perhaps due to quality issues with those bricks, it was found that some of them fell off after some time had passed. In the end, it was decided to use high-temperature concrete for construction. During the major repairs in 2007, local cracks were detected.
Pearl insulation powder is used to regulate the temperature within the refractory brick layer in the boiling furnace; it cannot be the real cause； It may be due to inadequate drying of the new furnace before it is put into use. Before using a new furnace, it is generally necessary to carry out a drying process; in a newly installed boiling furnace, there are usually three types of water present in the refractory bricks and insulation layers: free water, crystalline water, and residual bound water. At a temperature of 100 degrees, free water can be removed (at 120 degrees, for 36 hours at a constant temperature). At 350 degrees, crystalline water can be removed (at 390 degrees, for 24 hours at a constant temperature). At 650 degrees, the remaining bound water is removed (at 650 degrees, for 12 hours at a constant temperature). If the drying process is not carried out properly, during production the furnace operates at temperatures above 650 degrees; at such temperatures, the remaining bound water is released, and it reacts with sulfur trioxide to form condensed acids that cause corrosion. When the moisture content in the raw material is too high, it lowers the temperature at which sulfur trioxide condenses into acid. If the boiling furnace is shut down frequently or the temperature remains low, condensed acid is likely to form, leading to corrosion. General treatment method: When the furnace is operating normally, remove the cover for about 15 days to allow the water inside the refractory insulation layer to drain away. Once all the remaining bound water has been removed, the cover can be put back in place. Ensure that the moisture content of the material fed into the furnace meets the required level, ideally around 6%. Control the roasting temperature of the fluidized bed furnace and its air supply volume, striving to keep the generation of sulfur trioxide at the lowest level possible.
It is likely to be dew point corrosion; a dew point temperature of 150°C can be considered. To avoid dew point corrosion, it is necessary to keep the wall temperature above this dew point temperature, and a steel plate interlayer can be installed on the wall panel.