Refractory bricks in decomposition furnaces are key materials for protecting and maintaining the normal operation of decomposition furnaces. Their main function is to withstand thermal stress, physical erosion and chemical erosion in high temperature environments, while also supporting the decomposition furnace barrel. bricks play a key role in heat insulation and heat preservation during the production process, ensuring stable working conditions in high temperature areas.
Causes of damage to refractory firebricks in decomposition furnaces
1. Thermal stress caused by temperature changes
During the operation of the decomposition furnace, the temperature will undergo rapid changes, which will cause uneven expansion and contraction inside the refractory bricks, thereby generating thermal stress. After long-term repeated exposure to this thermal stress, refractories bricks are prone to cracking, peeling and breaking. In addition, the mud coating may desorb at high temperatures, resulting in pores or peeling on the bricks, further affecting their performance.
2. Physical and chemical erosion
There are various particles, gases and corrosive media inside the decomposition furnace, which cause physical and chemical erosion on the surface of the bricks. Physical erosion is mainly caused by the impact and friction of particles, resulting in surface wear, flaking and compaction. Chemical erosion is caused by the chemical reaction between high-temperature gas or liquid and bricks, which leads to corrosion and erosion of fire bricks. For example, some corrosive gases may penetrate into the interior of refractories bricks, react with their components, and form low-melting point compounds, which cause flaking and cracking of fire bricks at high temperatures.
3. Unreasonable design and improper operation
The design of the decomposition furnace and improper operation may also cause damage to refractory firebricks. Unreasonable design may include that the equipment structure does not fully consider factors such as thermal stress and erosion, resulting in certain parts being easily damaged. Improper operation is mainly reflected in temperature control, atmosphere adjustment, cleaning and maintenance. For example, too high or too low temperature may have an adverse effect on fire bricks; improper atmosphere adjustment may lead to excessive concentration of corrosive gases, accelerating the corrosion of refractories bricks; inadequate cleaning and maintenance may cause excessive accumulation of dust and impurities on the surface of refractory bricks, affecting their performance.
4. Fluctuation of refractory quality
The quality of refractory materials directly affects their service life and performance. Due to the uneven quality of raw materials in the supply chain and differences in manufacturing processes, the quality of refractory materials fluctuates greatly, and its stability and reliability cannot be guaranteed. This quality fluctuation may cause early damage to refractory firebricks during use.
5. Frequent start-up and shutdown
Frequent start-up and shutdown of the decomposition furnace during operation will cause large changes in the internal temperature difference, resulting in relative displacement between the refractory materials during the heating or cooling process. This relative displacement will produce friction shear force on the displacement surface and have a local tearing effect, causing surface cracks in the refractory material. These surface cracks will gradually expand during the repeated start-up and shutdown, and due to the erosion and diffusion of molten slag and corrosive media in the cracks, the local surface of the refractory material will peel off.
Measures to prevent damage to refractory bricks
For the above reasons, the following measures can be taken to prevent or slow down the damage of bricks:
1. Optimize design and operation: Rationally design the structure of the decomposition furnace, fully consider factors such as thermal stress and erosion; standardize the operation process to ensure the accuracy of temperature control and atmosphere adjustment; strengthen cleaning and maintenance work to keep the surface of refractories bricks clean and smooth.
2. Select high-quality refractory materials: Select refractory materials with stable quality and excellent performance to ensure their stability and reliability in extreme environments such as high temperature, high pressure and chemical erosion.
3. Control temperature changes: Reduce the thermal stress of fire bricks during temperature changes by preheating and slow heating; reasonably control the heating rate and cooling rate to avoid temperature stress caused by too fast or too slow.
4. Strengthen maintenance and care: Regularly check the wear and damage of refractory firebricks, and replace damaged refractory fire bricks in time; perform regular maintenance and care on refractories bricks, such as spraying protective layers, cleaning up accumulated ash, etc.
5. Reduce frequent start-up and shutdown: Rationally arrange production plans to reduce the frequent start-up and shutdown of the decomposition furnace; when it is necessary to start and stop, take appropriate protective measures, such as preheating and insulation.
