Rotary kiln cement production line

The company can undertake the design of new dry process cement production lines of various scales, such as 500t/d-10000t/d, to production trusteeship and technical transformation of old plants. The service mode can be EPC general contracting turnkey projects, or it can provide customized engineering design, civil construction, engineering installation, equipment R&D and manufacturing, personnel training, production commissioning, spare parts service, production trusteeship and technical transformation for increasing production and reducing consumption according to the owner's requirements.

1. Crushing and pre-homogenization

(1) Crushing In the process of cement production, most raw materials need to be crushed, such as limestone, clay, iron ore and coal. Limestone is the raw material used in cement production. After mining, the particle size is large and the hardness is high. Therefore, the crushing of limestone occupies a relatively important position in the material crushing of cement plants.

(2) Raw material pre-homogenization Pre-homogenization technology is to use scientific stacking and reclaiming technology in the process of raw material storage and retrieval to achieve preliminary homogenization of raw materials, so that the raw material yard has the functions of storage and homogenization at the same time.

2. Raw material preparation

In the cement production process, at least 3 tons of materials (including various raw materials, fuels, clinker, mixture, gypsum) must be ground for every ton of Portland cement produced. According to statistics, the power consumed by the grinding operation of the dry cement production line accounts for more than 60% of the power of the whole plant, of which raw material grinding accounts for more than 30%, coal grinding accounts for about 3%, and cement grinding accounts for about 40%. Therefore, it is of great significance to reasonably select grinding equipment and process flow, optimize process parameters, operate correctly, and control the operation system to ensure product quality and reduce energy consumption.

3. Raw material homogenization

In the production process of new dry cement, stabilizing the raw material composition entering the cellar is the prerequisite for stabilizing the thermal system of clinker burning. The raw material homogenization system plays a role in stabilizing the raw material composition entering the cellar.

4. Preheating and decomposition

The preheating and partial decomposition of the raw material are completed by the preheater, replacing part of the functions of the rotary kiln, so as to shorten the return kiln length. At the same time, the gas-material heat exchange process in the kiln in a piled state is moved to the preheater in a suspended state, so that the raw material can be fully mixed with the hot gas discharged from the kiln, increasing the gas-material contact area, fast heat transfer speed, and high heat exchange efficiency, so as to achieve the purpose of improving the production efficiency of the kiln system and reducing the heat consumption of clinker burning.

(1) Material dispersion

80% of the heat exchange is carried out in the inlet pipe. The raw material fed into the preheater pipe is impacted by the high-speed rising airflow, and the material turns upward and moves with the airflow, and is dispersed at the same time.

(2) Gas-solid separation

When the airflow carries the powder into the cyclone, it is forced to rotate in the annular space between the cyclone barrel and the inner barrel (exhaust pipe), and moves downward while rotating, from the barrel to the cone, and can extend to the end of the cone, and then rotates upward and rises, and is discharged from the exhaust pipe. (3) Pre-decomposition

The emergence of pre-decomposition technology is a technological leap in cement calcination process. It is to add a decomposition furnace between the preheater and the rotary kiln and use the rising flue at the kiln tail to install a fuel injection device, so that the exothermic process of fuel combustion and the endothermic process of carbonate decomposition of raw materials can be carried out rapidly in the decomposition furnace in a suspended or fluidized state, so that the decomposition rate of raw materials entering the kiln is increased to more than 90%. The carbonate decomposition task originally carried out in the rotary kiln is moved to the decomposition furnace; most of the fuel is added from the decomposition furnace, and a small part is added from the kiln head, which reduces the heat load of the calcination zone in the kiln, prolongs the life of the lining, and is conducive to large-scale production; because the fuel and raw materials are mixed evenly, the heat of fuel combustion is transferred to the material in time, so that the combustion, heat exchange and carbonate decomposition processes are optimized. Therefore, it has a series of excellent properties and characteristics such as high quality, high efficiency and low consumption.

5. Firing of cement clinker

After the raw materials are preheated and pre-decomposed in the cyclone preheater, the next process is to enter the rotary kiln for clinker firing.

In the rotary kiln, carbonates further decompose rapidly and undergo a series of solid-phase reactions to generate minerals such as ions in cement clinker. As the material temperature rises, minerals such as ions will become liquid phases, and the ions dissolved in the liquid phase react with ions to generate a large amount of ions (clinker). After the clinker is burned, the temperature begins to drop. The cement clinker cooler cools the high-temperature clinker discharged from the rotary kiln to a temperature that the downstream transportation, storage and cement mill can withstand, while recovering the sensible heat of the high-temperature clinker to improve the thermal efficiency of the system and the quality of the clinker.

6. Cement grinding

Cement grinding is the most important process in cement manufacturing and also the most power-consuming process. Its main function is to grind cement clinker (and gelling agent, performance adjustment material, etc.) to a suitable particle size (expressed in fineness, specific surface area, etc.), form a certain particle grading, increase its hydration area, accelerate the hydration rate, and meet the requirements of cement slurry coagulation and hardening.

7. Cement packaging

Cement is shipped in two ways: bagged and bulk.