RU2024809C1 - Set for producing cement clinker - Google Patents

Abstract

FIELD: sets for producing cement clinker. SUBSTANCE: set has shaft furnace 1 with cooler 2, mill 4, pelletizer 5 and second cross-flow shaft furnace 6 with cooler 7 and unloader. Ground moist components of source mixture with solid fuel are subjected to primary roasting in shaft furnace 1 where they are freed of carbon dioxide, physical and hydration water whose percentage in mass of source material is equal to 45. Then this semi-product is subjected to grinding in mill 4 and pelletizing in pelletizer 5. Final roasting is effected in cross-flow furnace 6 which is followed by cooling in cooler 7. Such arrangement of various units reduces power required for grinding by 35 percent, thermal energy by 10 percent and number of mills is halved. EFFECT: enhanced efficiency. 1 dwg

Description

 The invention relates to the design of installations for producing cement clinker in the building materials industry.

 The known design of the installation for drying, granulation and firing of a fluid flowing raw material mixture upon receipt of cement clinker. The installation comprises a lined rotary drum, a chain heat exchanger for drying and granulating the material, and the kiln itself [1].

 The design drawback of this installation is the high heat consumption for clinker burning and low productivity.

 A known installation, including a mill for grinding raw materials, a mine with a roller pelletizer integrated in its upper part. The installation is equipped with a system of blasting, power and discharge. The mine operates in countercurrent mode [2].

The design drawback is the granulation of the material before firing, which requires the installation of low-performance equipment and additional fuel consumption for the evaporation of water from the granules. In addition, the grinding of raw materials before firing requires additional energy compared with the grinding of fired raw materials, since in the first case, calcium carbonate and clay materials containing volatile constituents of CO ₂ and H ₂ O are subjected to heat treatment. This installation is also inefficient due to countercurrent operation.

 The aim of the invention is to reduce energy costs and simplify the preparation of raw materials.

 Figure 1 shows the proposed installation, a longitudinal section.

 The installation includes a cross-mine shaft furnace 1 with layer-by-layer burning of solid fuel for burning raw materials and a refrigerator 2 attached to the bottom of the furnace 1 with a feeder 3, a mill 4, a pelletizer 5, an additional shaft-type cross-section furnace with layer-burning solid fuel for sintering the material , a refrigerator 7 of the product, adjoined from below to the furnace 6, a feeder 8 of the product. The shaft furnaces 1 and 6 are equipped with incendiary devices 9 and 10, respectively, with burners 11 and 12, blow fans 13 and 14 and smoke exhausters 15 and 16. The refrigerator 2 is connected to the shaft furnace 1 by the duct 17 / and the refrigerator 7 is connected to the shaft furnace 6 by the duct 18.

 The groove 19 of the discharge device of the refrigerator 2 is connected to the loading end of the mill 4, and the heat 20 of its discharge device is connected to a pelletizer 5, which is connected to the second furnace 6. Ovens 1 and 6 and refrigerators 2 and 7 contain gas distribution walls 21, cavities 22 and floors 23 .

 Installation works as follows.

 The crushed wet components of the solid fuel feed mixture enter the hopper 24 and then into the shaft furnace 1. The material, descending down the shaft, passes successively the zones of ignition of solid fuel, drying and decarbonization. Then it enters the refrigerator 2 and then is fed by the feeder 3 into estrus 19 and into the mill 4, where it is ground to the required dispersion and homogenized. Then, from the unloading device of the mill 4, the ground material flows into the pelletizer 5 along the heat pipe 20 and then fired to the shaft furnace 6, where it is sintered and, after cooling in the refrigerator 7, with the help of the feeder 8, the clinker is sent for further processing.

 Solid fuel for sintering clinker enters the mill 4 or in the form of a sheaf enters the pelletizer 5. Arson of solid fuel in the layer in the shaft furnace 7 is carried out by the burner 12 through the ignition device 10. The shaft furnace 1 and 6 and the refrigerators 2 and 7 adjoined to them It is produced in the traditional cross-precise mode with layered burning of solid fuel. Hot air from refrigerators 2 and 7 through the ducts 17 and 18 enters the input cavity 22 of the furnaces and is used for layered burning of solid fuel. The gases leaving the shaft furnaces 1 and 6 are removed by dust exhausters 15 and 16 for dust cleaning.

 Decarbonization at the first stage of heat treatment allows grinding of the calcined product with widespread grinding plants, for example, tube mills, and the productivity of grinding plants in this case is much higher than when grinding raw materials, which forgives the raw material preparation system (reduces the number of mills for one furnace plant).

 Attaching estrus to the mill discharge device to a pelletizer, in this case preferably a press type, such as a roller type, reduces heat consumption since no water is needed for pelletizing. The use of a press pelletizer in this case is possible, since for the final firing of the decarbonized material, high strength pelletized product is not required. In such a process, during the secondary heat treatment, the pelletized product is not subjected to softening, since gas evolution and changes in structural strength occur from it, but, on the contrary, sintering increases as the adhesive strength increases.

 The use as a second stage of heat treatment of a shaft furnace with cross-flow of coolant and with layered burning of solid fuel allows the material to be heated almost inertialessly (3-5 minutes) before sintering. This provides the possibility of firing low-strength granules obtained by pressing without a binder.

 When firing crushed components of the raw material mixture in a shaft furnace 1 40-45 wt. % of the mixture during dehydration and decarbonization is carried out with a smoke exhauster 15 with exhaust gases and 55-60 wt.% of the initial mass of the material is subject to grinding. 70-80% by weight of fuel is consumed for firing the material in furnace 1, and this furnace, both in thermal load and in productivity, is 2-4 times more powerful. The decarbonated product has a high grindability and has a relatively lower mass, so the mill 4 is compact. In addition, the calcined material during grinding in the mill does not require a purge and, therefore, there is no need for dust cleaning (installation of filters) during grinding. This greatly simplifies the grinding system.

 The pelletizing of decarbonized material that does not have gas evolution during repeated firing is simplified, since high strength of the granulate is not required. In addition, the dehydrated and decarbonized material, when reheated before sintering, quickly heats up (in 3-5 minutes) and therefore also the pelletized product does not require high initial strength and dry pressing, for example, as shown in the drawing, provides flake grains suitable for repeated firing without destruction. Such a compact high-performance pelletizer, pressing a mass of material without moisture, also provides simplicity and compactness, which simplifies the installation for producing cement clinker.

Claims (1)

 A PLANT FOR PRODUCING A CEMENT CLINKER containing a mill, a pelletizer and a shaft furnace with a refrigerator, characterized in that, in order to reduce energy consumption and simplify the preparation of raw materials, it is equipped with an additional shaft furnace with a refrigerator installed in front of the mill, and the main and additional shaft furnaces are made with cross movement of the coolant.