SU1763833A1 - Device for burning cement clinker - Google Patents

Abstract

Usage: in the building materials industry in the production of cement clinker wet method. SUMMARY OF THE INVENTION: The apparatus comprises a rotating roasting drum with loading and unloading chambers. The roasting drum with chutes and gas flues is connected to a decarbonating reactor with a mixing chamber and a precipitating cyclone. The crushing device is connected to the discharge end of the rotating drying drum and to the system for transporting the material to the decarbonating reactor. The milling and drying unit is connected by a gas duct with a cooler and with a gas duct connecting the discharge end of the drying drum, and the drain with a system of devices for transporting the heat-treated material to the loading end of the drying drum 1 sludge.

Description

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The invention relates to devices for the heat treatment of raw materials in rotary kilns and can be used in the building materials industry in the production of cement clinker in the wet process.

A device for burning cement clinker is known that contains a rotary kiln of a wet production method with heat exchangers in the sludge drying zone, with loading and loading windows made around the kiln body in the decarbonization zone and connected via ring lined grooves with a calculator mounted outside the kiln (1 ).

The disadvantages of this device is that its practical implementation is difficult to implement, which is associated with the input

decarbonated material with a temperature of 950-1250 ° C from the stationary calciner to the rotary kiln through the windows in the side surface of the furnace body.

In addition, the disadvantages include limiting furnace capacity due to high furnace gas velocities | to which calcinator flue gases are added) and, therefore, due to the large amount of material removed from the furnace,

The closest to the proposed technical essence and the achieved result is a plant for burning cement clinker (2).

The cement clinker kiln plant includes a rotary kiln with loading and unloading chambers, gas ducts and chutes connected to a calciner with a mixture;)

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a rotary drying drum connected by a discharge end with a crushing and drying unit and an additional cyclone, whose estrus is connected to the calciner of the rotary kiln. In this case, the loading end of the rotary drying drum is connected to the precipitation cyclone of the rotary kiln, and the crushing-drying unit is also connected to the cooler. If necessary, between the crushing and drying unit and a refrigerator installed a combustion device.

In a known installation, the material is fed from the loading end of a rotating drying drum in parallel with the supply of waste gases from the calciner, i.e. It is planned to organize a drying mode for drying cement raw material sludge with a moisture content of 40%, and this, as is known, requires a large consumption of fuel, in particular, for the evaporation of moisture. These design features, including the presence of ring loops, determine the complexity of the aerodynamic system that is not insured against the occurrence of ring currents that disrupt the clinker process. As is apparent from the description of the invention, exhaust gases with a high temperature of about 400 ° C and higher emerge from the rotating dryer drum, which requires the use of special-purpose smoke pumps operating under conditions of a high-temperature dust-gas environment, which is an intractable problem.

Installation of an additional firebox recommended in a.s. No. 1385745, also leads to increased installation of fuel consumption and increased capital costs. In addition, the presence of an additional furnace and calciner operating only in the mode of dissociation of the carbonate component (since it is heated in a rotating dryer drum and a crushing and dryer unit) creates conditions for burning more fuel in a rotary kiln - about 40-50 % of the amount of fuel consumed by the clinker firing plant. Burning 40–50% of the fuel in a rotating short kiln during its high-temperature mode leads to the formation of a high content of nitrogen oxides in the kiln gases, which are environmentally harmful.

The aim of the invention is to reduce energy costs, increase productivity and reduce pulverization.

FIG. 1 is a diagram of an installation for calcining cement clinker;

The cement clinker kiln plant contains a rotary kiln 1, a cooler 2, a calciner 3, a rotary kiln 4, and a dedusting system 5.

The rotary kiln 1 is connected via a loading chamber 6 and a chute 7 to

by the precipitating cyclone 8 of the decarbonating reactor 3, and through the flue 9 with the mixing chamber of the decalcating reactor 3, the unloading chamber 10 of the rotary kiln 1 is connected to the cooler 2.

The rotary kiln 1 at the discharge end and the decarbonating reactor 3 are equipped with burners (not shown). The rotary dryer drum 4 is equipped with heat exchangers 11, for example, in the form of chain curtains, the design of which is determined based on the natural properties of the raw material.

The feed end 12 of the drying drum 4 is connected to a system of dedusting devices 5, including, for example, cyclones, an electrostatic precipitator, etc., and which are common for both the rotary kiln 1 and the decarbonization reactor 3, and as described above dl

drying drum 4. The discharge end 13 of the drying drum 4 is connected with a system of devices 14 for transporting the dried material to the decarbonization reactor 3, and the volume of the internal space of the drying drum 4 is connected to the precipitating cyclone 8 from the discharge end 13 on its side. 14 for transporting material comprises

for example, a bunker, an elevator, a feeder for supplying the material heat-treated in a drying drum 4 to the decarbonating reactor 3.

The clinker kiln also contains a grinding and drying ai regatta 16 for heat treatment of the clay component, connected by aerodynamic paths to a cooler 2, a decalcifier 3, and a flue 15 connecting the precipitating cyclone 8 of the decarbonizer 3 to the drying drum 4.

If necessary, to crush the dry granules of the material after the drying drum 4, a crushing device 17 is installed, connected with a system of devices 14 for transporting the material — the dried mixture to the calciner 3. The loading chamber 6 of the rotary kiln 1 is connected to the system of 18 other materials, conveyor of non-ground blast furnace slag.

In this case, the system of devices 18 includes, for example, bins for storing slag, a feeder-dispenser, and a chute entering the feed chamber 6.

Installation for burning cement clinker works as follows.

Cretaceous cinder sludge with diluent added with a titer of 96.0%, humidity of 28% and a flow of 70 mm is fed with a slurry feeder to the loading end 12 (part) of a rotating drying drum 4 connected by an aerodynamic gas duct 15 to a decarbonizer 3 and equipped with heat exchangers 11 for example, chain curtains with free-hanging ends. The clay (clay component), burned at a temperature of 150-400 ° C and crushed to residue on a 02-sieve, equal to 6%, is fed there with a feeder-dispenser for bulk materials. In this case, it is advisable to heat the clay in the milling and drying unit 16, for example, in a simultaneous grinding and drying mill, using the heat of gases after the calciner 3, and the air after the cooler 2.

Falling into the rotating tumble dryer 4, the chalk-burning sludge and the heat-treated clay are mixed, and the moisture content of the mixture is 24%. However, the transport capacity of such a mixture remains high, due to the lack of plasticity properties of the clay, and the formation of the charge does not occur. The materials are well mixed in the rotating drying drum 4 in the region of the chain heat exchangers 11 and, due to the contact with the latter, are dried.

The speed of rotation of the drum 4 is adjusted in such a way as to ensure the temperature of the material at the exit from it in the range of 150-400 ° C. The surface density of the heat exchangers 11 is calculated so that the temperature of the gases leaving the drum 4 is in the range of 200-260 ° C. The velocity of the gases at the outlet of the drying drum 4 is, for example, 8-12 m / s. In this case, the chain curtain 11 is a filter for the deposition of particles entrained in gas from the precipitating cyclone 8 of the decalcator 3.

The length of the drum 4 is chosen to be approximately twice the length of the drying and heating zone of the material (up to 400 ° C) of the rotary kiln of the wet clinker production method. The crushed material is fed by an elevator to a decarbonating reactor 3 of a known construction, in which from 40 to 80% of the total fuel required for burning the clinker is burned.

From the decarbonating reactor 3, the material in a wake-up stream with gases enters the mixing chamber of the carbonizer 3, in which it mixes with the exhaust gases from the rotary kiln 1, having a temperature of 1100 ° C, which ensures further decarbonization of the material and a decrease in the temperature of the gas-dust mixture to 850 ° C .

The vacuum created by the exhaust fan causes the mixture to be precipitated

the cyclone 8, in which the material flows are separated, the gases through the duct 15 are directed to the drying drum 4, and the material into the rotary kiln 1 to complete the clinker formation process.

The temperature of the material and gas flow in this area remains almost unchanged and is about 850 ° C, i.e. significantly higher than the condensation temperature of alkalis formed in rotary kiln 1 at elevated temperatures.

Alkali condensation occurs in a rotating drying drum 4 (mixer), which provides an increase in the reliability of operation of the rotary kiln and, accordingly, of the entire installation as a whole.

Therefore, the content of alkalis in the raw mix can

be not as tough as when fired in dry kilns with heat exchangers.

In order to maximize the heat consumption for burning clinker into the rotary kiln 1, the system of devices 18 introduces unground slag or its analogs. With an increase in the amount of slag introduced, the heat capacity of the rotary kiln 1 also increases due to the larger fraction

burning fuel.

The clinker is cooled in the refrigerator 2, the heated air from which is used for oxidation of the fuel in the calciner 3 and for heat treatment

clay in the grinding and drying unit 16, which contributes to reducing the energy costs of clinker burning. The proposed design of the cement clinker roasting plant is the most promising for

transfer of plants wet method to the combined.

In this case, the total energy consumption for clinker production will be the whole via close to the dry method.

Reconstruction of the rotary kiln 5 x 185 m will increase its productivity by almost 2 times, and reduce fuel consumption for clinker burning by 25-30%.

The design of the kiln plant provides effective drying and mixing of materials of low humidity in the most simple and well-studied device — a drying drum, in which the process of forming the coating from materials containing chlorides and alkalis can also be controlled.

Design features cause the suppression of the occurrence of various ring currents of the aerodynamic system, does not require additional installation of smoke exhausters operating under conditions of highly dusty and high-temperature flows.

Regulated heat exchange makes it possible to obtain a low temperature of flue gases, and the excess heat available in the calciner can be used for other purposes.

The supply of material heated to a temperature of 200–400 ° C to the calciner changes the nature of its operation, therefore, in such a system, it is possible to burn significantly more fuel at temperatures below 1500 ° C at low values of a, which will sharply reduce the formation of nitrogen oxides.

Claims (1)

Invention Formula A cement clinker roaster, comprising a rotating roasting drum with loading and unloading chambers, through gas ducts and leaks connected to a decarbonating reactor with a mixing chamber and a precipitating cyclone, rotating the drum, the discharge end of which is connected to the precipitating cyclone of the decarbonating reactor gas duct, a grinding / drying unit, a dedusting system, and a refrigerator, which is equipped with an additional crushing unit in order to reduce energy costs, increase productivity and reduce dust removal. a device connected to the discharge end of a rotating tumble drum with a system of a device for transporting the material to the decarbonating reactor, and the grinding and drying device egat flue connected with a refrigerator and a gas flue, connecting the discharge end of the drying drum and the precipitating cyclone of the decarbonating reactor, and the diverter - with the system of devices for transporting the heat-treated material to the loading end of the drying drum. L / Yyyy / g / 3 // vxVV about