Refractory engineering plays a crucial role in the cement industry, as it affects the quality of the final product, the lifespan of combustion systems, energy costs, and emissions. ZHENJIN REFRACTORIES is a leading global supplier of refractory products and lining systems for the cement industry. Our products are designed to meet the latest plant types and environmental regulations while providing innovative solutions. We offer complete services from raw materials to design, development, application, and recycling of used materials with a strong focus on customer satisfaction. Our company operates with structured procedures, rigorous inspections, and effective quality management to ensure the highest possible standards.
The preheater is a component installed upstream of the calciner and the rotary kiln of a clinker/cement plant.
By means of the counterflow principle, the injected raw meal is heated in stages by the upward flow of hot gas, whereby the meal is calcined (deacidified) by up to about 95 %. Depending on the raw mealʻs moisture content and plant capacity, single or dual preheaters with three to five cyclone stages are used.
The calciner is installed under the lowest cyclone stage. In this plant section, the raw meal is calcined (deacidified) by up to about 95 %. The energy input required by this stage (about 60 % of the plantʻs overall heating demand) is provided by means of special calciner burners, which can be operated with primary as well as secondary fuels.
The tertiary air duct is connected to the calciner.
3. Rotary kiln
Slightly angled downwards, the kiln's rotation transports the percalcines raw meal from the inlet to the discharege end (kiln hood), whereby the temperature increases along the kiln's length. Hereby, the required clinker phases are created at material temperatures up to 1450℃.
4. Kiln hoods
Via the kiln hood, the finished clinker is discharged from the kiln. Simultaneously, the process gases are conducted from the clinker cooler through the hood and into the rotary kiln. In plants with daily clinker outputs up to about 7500 tons, the tertiary air ducts (TAD) are connected mainly to the kiln hood. In larger plants, the TADs are connected behind the kiln hood.
Therefor, thermochemical resistance has top priority when selecting the most suitable refractory materials for the hood lining. Because of the particularly sensitive behaviour during heat-up, the use of refractory materials that are insensitive to heating up is preferable.
5. Tertiary air ducts
The combustion air required for the calciner is diverted from the kiln hood by means of the tertiary air duct which bypasses the kiln.
Various flaps and gate valves are used to control the tertiary airflow. By means of this arrangement – also known as AS (air separate) – dust generation in the kiln is reduced significantly.
The clinker cooler uses air to rapidly cool the hot clinker leaving the kiln, thereby stabilizing the C3S clinker phase and obtaining a high efficiency level. In modern clinker coolers, the cooling air passes through the clinker at right angles, whereby the air absorbs the thermal energy. Via the kiln hood, this recuperated heat is passed to the rotary kiln as secondary air, or as tertiary air via the tertiary air duct.
ZHENJIN REFRACTORIES products
Periclase-hercynite refractory bricks
Magnesia—alumina spinel bricks
GUIMO abrasion resistant bricks
Spalling resistant high alumina bricks
HX-35 low thermal conductivity, abrasion resistant bricks
High-strength alkali-resistant bricks
Composite structure GUIMO bricks
Refractory castable for burner of cement kiln
Anti-coating castable castable
Steel-fiber reinforced castable
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