Refractory Configuration and Optimization for a 5000t/d Clinker Line (3)
Refractory materials are developing towards environmental friendliness, strong adaptability, and long service life. Rongsheng Refractory Materials Factory supplies refractory materials for kilns used in 5,000 t/d clinker production lines. Rongsheng Refractory Materials Manufacturer leverages its innovative capabilities in refractory castables while focusing on customer needs, aiming to provide high-quality, long-life refractory lining materials for high-temperature industrial furnaces. Contact Rongsheng for free solutions.
Refractory Lining Configuration for a 5,000 t/d Cement Clinker Production Line
This article focuses on the refractory configuration for a 5,000 t/d cement clinker production line. The cement firing system involves a complex chemical process from raw meal to clinker, going through stages such as preheating in the preheater, decomposition in the calciner, high-temperature calcination, and cooling. The refractory materials used in each stage must be adapted to this process.
Analysis of Certain Defects in the Current Configuration and Improvement Plans
(1) Preheater System
- Severe scaling at the smoke chamber and precalciner necking, impacting ventilation.
- Cause: The production line was designed to produce 5,000 tons per day, but actual production typically reached 5,500 tons, resulting in an overload of over 10%. This increased the kiln’s thermal load and the likelihood of scaling at the kiln tail. Furthermore, the increased use of anthracite and low-quality coal resulted in less than ideal combustion, increasing the likelihood of incomplete combustion and the rate of scaling. In short, scaling can be caused by a variety of factors, including operational factors, fuel, and raw material issues. In severe cases, it can lead to the cessation of rotary kiln operation.
- Improvement Plan: In actual production, scaling at the kiln tail is not limited to the smoke chamber, but can sometimes extend to the precalciner necking and the fifth-stage drum discharge chute. Therefore, it is recommended to expand the scope of anti-scaling castables, such as using anti-scaling castables throughout the entire section below the fifth-stage drum discharge chute.
- The castables on the top of the cyclone and decomposition furnace are prone to falling off, posing a production safety hazard.
- Causes: Poor anchorage and welding quality, design flaws, and excessively rapid cooling can all cause the top castables to fall off, resulting in numerous fatalities on the production line.
- Improvement Solution: Correct the design flaws, eliminate the calcium silicate board interposition, and use only lightweight castables. Use ceramic anchors and anchor bricks, etc.
- The kiln tail tongue is prone to damage.
- Cause: Due to the erosion of high-temperature materials and corrosion from the kiln tail flue gas, the steel plate under the kiln tail tongue is easily damaged, which in turn damages the kiln tail tongue, significantly impacting kiln operation.
- Improvement Solution: Use prefabricated components and eliminate the bottom steel plate to extend service life.
- Small-scale repairs are labor-intensive and time-consuming.
- Cause: After two years of operation in a new kiln, some refractory materials in the preheater system may be partially damaged. Because the preheater is hollow, scaffolding must be erected during construction, which reduces maintenance time.
- Improvement plan: Using spray paint for construction can save time and energy, and should be promoted vigorously.
(2) Rotary Kiln System
- The kiln mouth castable is easily damaged, resulting in a long construction time.
- Cause: Because the kiln mouth is prone to deformation, the castable is currently cast as a single piece. However, the casting cycle is long, and the baking time may be insufficient. As a result, the kiln mouth refractory cycle is significantly lower than that of other parts of the kiln.
- Improvement: Using plastic castables eliminates the need for formwork, saving construction time. Curing and baking are unnecessary, making it suitable for routine maintenance.
- Firing zone magnesia-chrome bricks does not meet environmental requirements.
- Cause: Magnesia-chrome bricks react easily with sulfur in cement rotary kilns, generating some toxic hexavalent chromium ions, which can cause water pollution. Consequently, European countries have imposed very strict restrictions on the production and use of magnesia-chrome bricks.
- Improvement: Using dolomite bricks, magnesia-iron spinel bricks, and magnesia-alumina spinel bricks.
- Spinel bricks have a large thermal conductivity, causing the kiln body temperature to rise.
- Cause: Spinel bricks are currently used near the No. 2 wheel rim and have a good service life. However, their main drawback is their high thermal conductivity, which increases the drum temperature and poses a risk to kiln operation. This also results in significant heat loss.
- Improvement: Use high-quality silica-molybdenum bricks.
(3) Short Burner Head Life
- Cause: Due to the harsh operating environment of the coal injection pipe, such as large temperature differences, a thin refractory layer, a strong reducing atmosphere, and high-temperature radiation, the head has a short service life.
- Improvement: The head is prefabricated and manufactured in advance, with adequate curing and baking, for optimal performance.
(4) The top castable of the kiln hood is prone to partial detachment
Cause: See the top of the preheater.
(5) Cooler System
- Susceptible Wear of the Low Wall
- Cause: The high-temperature clinker exiting the rotary kiln is directly rubbed against the low wall during cooling, and the alternating contact between hot and cold air causes rapid wear of the low wall.
- Improvement: Use highly wear-resistant castables.
- Susceptible detachment of the top castable
- Cause: See the top of the preheater.
(6) Tertiary air duct bends are prone to wear.
- Cause: The hot air from the kiln head cooler contains a large amount of clinker particles, which rub against the castable at the bend. Typically, castables only last three months.
- Improvement: Use highly wear-resistant castables.
(The end)