Process flow of cement production line [designed by Henan Hongxing Mining Machinery Co., Ltd.];
1, pulverizing and pre-homogenizing
(1) In the process of producing crushed cement, most raw materials are crushed, such as limestone, clay, iron ore and coal. Limestone is the most used raw material in cement production. After mining, the particle size is large and the hardness is high, so the crushing of limestone plays an important role in the crushing of materials in cement plants.
(2) Pre-homogenization of raw materials Pre-homogenization technology is to realize the initial homogenization of raw materials by using scientific stacking technology in the process of raw material storage and retrieval, so that the raw material storage yard has both storage and homogenization functions.
2, raw meal preparation
In the process of cement production, every 65,438+0 tons of portland cement is produced, at least 3 tons of materials (including various raw materials, fuels, clinker, mixtures and gypsum) are ground. According to statistics, the grinding operation of dry cement production line consumes more than 60% of the power of the whole plant, of which raw meal grinding accounts for more than 30%, pulverized 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 and correctly operate and control the operating system to ensure product quality and reduce energy consumption.
3, raw meal homogenization
In the process of new dry cement production, stabilizing the composition of into the pit raw meal is the premise of stabilizing the thermal system of clinker burning, and the raw meal homogenization system plays the final role in stabilizing the composition of into the pit raw meal.
4, preheating decomposition
The preheating and partial decomposition of raw materials are completed by the preheater, which replaces some functions of the rotary kiln, thus shortening the time of returning to the kiln. At the same time, the heat exchange process of gas and material in the kiln is carried out in a stacked state and moved to the preheater in a suspended state, so that the raw materials are fully mixed with the hot gas discharged outside the kiln, the contact area between the gas and the material is increased, the heat transfer speed is high, and the heat exchange efficiency is high, thus achieving the purposes 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. Under the impact of high-speed updraft, the raw meal entering the preheater pipeline 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 cylinder, it is forced to rotate in the annular space between the cyclone cylinder and the inner cylinder (exhaust pipe), and moves downward while rotating, from the cylinder to the cone, to the cone end, and then turns upward and is discharged from the exhaust pipe.
(3) Pre-decomposition
The emergence of pre-decomposition technology is a technological leap in cement calcination process. A precalciner is added between the preheater and the rotary kiln, a kiln tail ascending flue is used, and a fuel injection device is arranged, so that the exothermic process of fuel combustion and the endothermic process of raw material carbonate decomposition are carried out rapidly in the precalciner in a suspended state or a fluidized state, and the decomposition rate of raw materials entering the kiln is improved to over 90%. The carbonate decomposition task originally carried out in the rotary kiln was transferred to the decomposing furnace; Most of the fuel is added from the calciner and a small part is added from the kiln head, which reduces the heat load of the calcining zone in the kiln, prolongs the service life of the furnace lining and is beneficial to large-scale production; Because the fuel is evenly mixed with the raw meal, the combustion heat of the fuel 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. Combustion of cement clinker
After the raw meal is preheated and pre-decomposed in the cyclone preheater, the next process is to enter the rotary kiln for clinker sintering.
In the rotary kiln, carbonate is further rapidly decomposed and a series of solid-state reactions occur to produce minerals such as cement clinker. As the material temperature rises, etc. Minerals will become liquid phase, and those dissolved in the liquid phase will react to produce a large number of clinker. After the clinker is fired, the temperature begins to drop. Finally, the cement clinker cooler cools the high-temperature clinker discharged from the rotary kiln to the temperature that the downstream transportation, storage and cement grinding can bear, and at the same time recovers the sensible heat of the high-temperature clinker, thus improving the thermal efficiency and clinker quality of the system.
6, cement grinding
Cement grinding is the last process of cement manufacturing, and it also consumes the most electricity. Its main function is to grind cement clinker (and cementing agent, performance adjusting material, etc.). ) to a suitable particle size (expressed by fineness and specific surface area, etc.). ), form a certain particle gradation, increase its hydration area, accelerate the hydration speed, and meet the requirements of setting and hardening of cement paste.
7, cement packaging
Cement can be transported in bags and in bulk.
The main machinery and equipment needed in the whole process of cement production are crusher, rotary kiln, cement mill, raw meal mill and so on.
/yuzhiyanran