From the petroleum coke calcining process, it can be seen that when using indirect heating to transfer heat, silica bricks are used as furnace masonry materials. Because of their high thermal conductivity, they are more suitable for this heating method of the calcining furnace and are ideal refractory materials. However, in the actual operation process, affected by various factors, silica refractory bricks are damaged and eroded, reducing their service life, and corresponding measures need to be taken to improve and extend their service life.
Main factors affecting the life of petroleum coke can calcining furnaces
From the design of petroleum coke can calcining furnaces, the expected design service life is generally long, but due to its technical conditions, operation and maintenance, masonry quality, etc., the service life after being put into use is significantly shortened. The factors affecting the life of the calcining furnace are analyzed in detail, mainly as follows:
① Quality of silica firebricks, such as most silica fire bricks are produced by small manufacturers, and due to limited technical capabilities, the quality of silica bricks is difficult to meet the requirements of the calcining furnace;
② Quality of furnace masonry, affected by the deviation of silica firebrick shape and size, the furnace masonry may have mud that is not fully filled, and there are too large brick joints, which affects the quality of furnace masonry;
③ Quality of furnace baking, such as the furnace body is not tightly sealed, when the temperature is too high after it is put into use, it may cause the fire channel wall to be burned;
④ Operational problems in use, such as delayed coke with excessive volatiles, the tank wall burns, and the maintenance and management work is not done well after use, such as the coking shed material is not properly handled, causing damage to the tank body.
Application of silica fire bricks in petroleum coke tank calcining furnace and analysis of silica refractory brick erosion causes
① Analysis of silica refractory brick coking:
The existence of coking problems is often seen in fire channel damage and furnace wall damage. The reasons are attributed to the volatile matter and ash of petroleum coke. Taking the ash as an example, there are many metal oxides such as Na2O, K2O, Al2O3 and other components in it. Under high temperature conditions, they will react with silica firebrick SiO2 to produce low melting point substances, which will cause the surface of the silica refractory brick to be molten. As for volatiles, when there are excessive volatiles in petroleum coke, due to excessive volatile vapor retention on the material tank, the temperature will drop at this time, and the vapor will adhere to the tank wall in liquid form, resulting in coking.
② Analysis of silica brick sintering:
During the operation of the calcining furnace, it is easy to have obvious problems with furnace temperature changes. If the furnace temperature is not reasonably controlled, the local temperature of the furnace body will increase, causing sintering damage. At the same time, the reaction between refractory materials and impurities in petroleum coke may also cause melting damage. The reason is that when the temperature environment exceeds 1300°C, the metal oxides NaO, K2O, and Al2O3 in petroleum coke will react with silica fire bricks to produce low-melting products, which will cause burning problems. In addition, during the calcination process, although moisture and volatiles are eliminated, there is residual sulfur content, which may also become a cause of melting damage. The reason is that silicon bricks may be corroded by sulfur. The higher the sulfur content, the more obvious the corrosion of silica bricks.
