Product overview

 Cement production line is a series of supporting equipment for cement production. It is mainly composed of crushing equipment, homogenizing equipment, raw material preparation equipment, drying equipment, preheating decomposing equipment, clinker burning equipment, cooling equipment, grinding equipment, packaging equipment, transportation equipment, environmental dust collecting equipment and so on. Chaoyang Jiantou Heavy Machinery Co., LTD. provides following service: cement production line process design, civil construction, complete sets of equipment, installation and commissioning, technical services, engineering general contracting.

Processing parameter

 In the process of cement production line, each 1 ton of portland cement needs to be grinding 3 tons of materials (including various raw materials, fuel, clinker, mixture, gypsum). According to statistics, dry cement production line grinding operation needs to consume more than 60% of the power of the whole plant, including raw material grinding accounted for more than 30%, coal grinding accounted for about 3%, cement grinding accounted for about 40%. Therefore, reasonable selection of grinding equipment and process flow, optimization of process parameters, correct operation, control operation system, to ensure product quality, reduce energy consumption has great significance.

Method

 Cement production with limestone and clay as the main raw material, after crushing and raw ingredients, through vertical mill grinding into raw material, and then feeding in cement rotary kiln burning into clinker. The clinker with an appropriate amount of gypsum, adding some mixed materials or additives, then rolled by roller press and cement mill grinding into cement, and then transported by packaging machine or bulk machine from factory. Cement production equipment can be divided into dry cement production line and wet cement production line according to different raw material preparation methods. (1) Dry cement production process. The raw materials are dried and grinding at the same time, or dried raw materials powder firstly and then fed into a dry rotary kiln for calcining into clinker. There is also a method of making raw material ball by adding raw material powder to proper amount of water and sending it to clinker in Lipol kiln, which is called semi-dry method. It is one of the dry production process. The main advantage of dry process production is low heat consumption. The heat consumption of clinker in dry process kiln with pre-heater is 3140 ~ 3768 coke/kg. The disadvantage is that raw material composition is not easy to be uniform, high dust in the workshop and high power consumption. (2) Wet cement production process. The raw material is grinding into raw material slurry and fed into a wet rotary kiln for clinker. There is also a method of the raw material prepared by wet method is dehydrated, and then the raw material is made into the clinker in the kiln, which is called the semi-wet method. It is one of the wet production process. Wet production has the advantages of simple operation, easy control of raw material composition, good product quality, convenient slurry transportation, less dust in the workshop, etc. The disadvantage is high heat consumption; clinker heat consumption is usually 5234 ~ 6490 coke/kg.

Included equipment

 The main equipment of cement production line includes: cement rotary kiln, cyclone pre-heater, cooler, crusher, vertical mill, roller press, cement mill, coal mill, dryer, dust collector, packing machine, bulk machine, conveyor, electrical control, etc.

Processing

Prehomogenizing (1) Crushing: In cement production, most of raw material need to be crushed, such as limestone, clay, iron ore or coal, etc. Limestone is the raw material with the largest amount of cement, the granularity after mining is larger and the hardness is higher, so the crushing of limestone occupies a relatively important position in the crushing of cement plant materials. (2) Prehomogenization of raw materials: Prehomogenization technology is the application of scientific stacking and reclaiming technology in the process of raw material storage and reclaim, to realize the initial homogenization of raw materials, so that the raw material storage yard has the functions of storage and homogenization at the same time. In the process of new dry cement production, stabilizing raw material composition is the premise of stabilizing clinker burning, and the homogenizing system of raw material plays a role of stabilizing raw material composition in kiln. Preheating decomposition use pre-heater to complete preheating and decomposition of cement raw materials, replace some functions of rotary kiln, shorten the length of rotary kiln. Material in suspension preheating state, the process of heat transfer between gas and material is realized in the rotary kiln, the raw material is mixed with the hot gas discharged from the rotary kiln, which increases the contact area of the gas material, high heat transfer rate, high heat exchange efficiency, improve the production efficiency of rotary kiln system, reduce the clinker burning heat consumption. (3) Predecomposition. The appearance of predecomposition technology is a technological leap of cement calcining process. It is to set up a decomposition furnace between the pre-heater and the rotary kiln, and use the rising flue at the kiln end to set up a fuel injection device, so that the heat release process of fuel combustion and the heat absorption process of raw material carbonate decomposition can be carried out rapidly in the decomposition furnace in a suspended or fluidized state, so that the decomposition rate of raw materials into the kiln increased to more than 90%. The carbonate decomposition task originally carried out in the rotary kiln was moved to the decomposition furnace; most of the fuel is added from the calciner, while a small part is added from the kiln head, which reduces the heat load of calcining belt in the kiln, prolongs the life of the lining material, and is conducive to the production of large scale. Because the fuel and raw material are mixed evenly, the fuel combustion heat is transferred to the material in time, so that the combustion, heat exchange and carbonate decomposition process is optimized. Therefore, it has a series of excellent performances and characteristics such as high quality, high efficiency and low consumption. After the raw materials are preheated and predecomposed in the cyclone pre-heater, the next process is to enter the rotary kiln for the firing of clinker. In the rotary kiln, the carbonates further decompose rapidly and a series of solid reactions take place to form minerals in cement clinker. As the temperature of the material increases, the minerals will turn into liquid phase. As the clinker burned, the temperature begins to drop. Finally, cement clinker cooler cools the high temperature clinker discharged from rotary kiln to the temperature that can be borne by downstream conveying, storage and cement mill. Meanwhile, sensible heat of high temperature clinker is recovered to improve the thermal efficiency of the system and the clinker quality. (4) Cement grinding. Cement grinding is the final process of cement manufacturing and also the most power-consuming process. Its main function is to grind the cement clinker to the appropriate particle size, form a certain particle size distribution, increase its hydration area, accelerate hydration speed, and meet the requirements of cement slurry setting and hardening. (5) Cement packaging. Cement is shipped in bags and in bulk. The proportion of bulk must reach more than 70% according to the national standard. The development of bulk cement is a big trend in China.