Reasons for coke oven damage

In terms of the following aspects: 1. The locomotive was damaged during the production process, 2. Poor quality of coke 3. Furnace construction quality 4. Inadequate regular maintenance 5. Inadequate process management

This issue has been discussed on the forum regarding abnormal damage to coke ovens: 1. The materials used in constructing the oven (silicon bricks, silicon mortar) do not meet the standard requirements. In particular, their physical and chemical properties are too poor; even when used under the normal production conditions specified in the design, they tend to get damaged, causing the coke oven to age prematurely. 2. The masonry quality of the coke oven is too poor. The geometric dimensions of the furnace body exceed the tolerance requirements in various aspects, the mortar joints between the bricks are not properly filled, and after operation, there is severe leakage of raw gas or purified gas used for heating, which easily leads to localized high temperatures. Especially in the areas of the incline that cannot be repaired and inside the regenerator where damage is difficult to detect, once damage occurs it is hard to remedy. 3. The quality of the oven is poor. Due to poor heating quality, large horizontal cracks appeared on the walls of the carbonization chamber; cracks also formed between the walls of the heat storage chamber and the chutes, while vertical cracks appeared at the head end of the carbonization chamber, resulting in severe inherent damage. Poor management of the furnace’s iron components, or smoke and fire coming from the furnace door, can damage these components, thereby preventing the furnace from having the protection it needs. In this way, under the impact of cyclic changes in mechanical load and temperature, the furnace body can deform rapidly or even collapse. 4. The expansion pressure of the coal used for coking is too high, or the contraction is too low. This causes severe damage such as deformation of the walls in the carbonization chamber, protrusions or indentations, and even wavy deformations on the walls on the machine side and the coke side. 5. Uneven furnace temperature. Charring or over-charring occurs frequently; the coking time is either too long or too short, or coke is not extracted as planned. Disordered production management leads to difficulties in pushing out the coke, causing deformation of the furnace walls. 6. Poor thermal maintenance: when local damage to the furnace body is detected, it is not repaired in a timely manner, creating a vicious cycle that accelerates the deterioration of the furnace body. 7. Unreasonable values of certain key indicators lead to changes in other process parameters, causing harm to the coke oven. Damage to the furnace wall may occur if it is difficult to push the coke out. 8. The comprehensive management level of the coking workshop is low, with a lack of professional indicators and control methods. It is impossible to eliminate accidental operations, and such arbitrary actions can cause localized damage to the coke oven. The abnormal damage to the aforementioned coke ovens is purely a matter of production management and technical management issues. As long as management in all aspects is strengthened, the above situations generally will not occur.

In fact, the lifespan of a coke oven is greatly related to its initial baking process and subsequent maintenance. A proper furnace drying lays a solid foundation for the quality of the coke oven.

Normal reasons for coke oven damage: 1. Influence of temperature changes. During the production process, thermal shock caused by repeated opening and closing of the furnace door, coal loading, and coke removal leads to effects on the furnace walls. Especially in the burner area, erosion or cracks begin to occur 3 to 5 years after it is put into use. 2. Action of mechanical force. After cracks or deformation occur in the walls of the carbonization chamber, the mechanical stresses generated by opening and closing the furnace door and pushing coke cause the cracks in the furnace walls to widen or the deformation of those walls to worsen. 3. Physicochemical effects: Silica, the main component of silica bricks, is not resistant to corrosion by alkaline slag at high temperatures; it can react with the alkaline oxides present in coal, resulting in the formation of low-melting-point silicates. Due to the different linear expansion rates of these silicates and silica bricks, they tend to detach from the silica brick body under mechanical stress. Furthermore, the reducing gases such as hydrogen and carbon monoxide produced by coal carbonization reduce the silica in silicon bricks to silicon monoxide at high temperatures, which then escapes in gaseous form (this reaction also occurs at lower temperatures in the presence of metallic iron), thereby reducing the silica content in the silicon bricks and causing them to become porous and loose, with a pitted surface. 4. Furnace length increase and carbon deposition. The walls of the carbonization chamber develop cracks over time due to mechanical stress and thermal shock from temperature changes. These cracks widen during coal loading as a result of cooling-induced contraction. A few hours after coal is loaded, the temperature of the masonry rises, causing corresponding expansion; however, the original cracks are already filled with deposited carbon, so they cannot close completely and instead expand outward, causing the furnace body to elongate. Over and over again, this causes the cracks to widen and increase in number, thereby causing the length of the furnace to keep growing each year.

There are many reasons for coke oven damage; the key factors are the maintenance of the coke ovens (including heat treatment methods as well as the management and maintenance of metal components), along with proper management. Other factors include oven drying, the quality of refractory materials, and temperature control