SU1435909A1 - Apparatus for heat treatment of loose finely divided materials - Google Patents

Abstract

The invention relates to the use of construction materials, namely, installations for the firing of cement raw materials for the dry process for the production of cement clinker. The purpose of the invention is to intensify the processes of heat exchange in the furnace shaft heat-memory system. fSfia of this along the axis of the small continuous shaft 2, located above the baking countercurrent heat exchanger 1, is installed

Description

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with

insert 6 in the form of a reverse cone with a flat base, whose diameter is 0.3-0.9 times the diameter of a small flat shaft; the height of the cone is. 1.5-2.5 times the diameter of its base, and the distance from the top edge of the heat exchanger to the base of the cone is 1.0-2.0 times its height. The shape of the surface of the insert 6 is determined by the shape of the inner surface of the shaft 2.. At the location of the insert, the co-I can be made in the form of an I hollow open truncated reverse I cone with a perforated surface I. The raw material chutes 7 of the shaft 2 are located above the base of the reverse cone, at a distance of not more than 7 diameters of the base of the cone from it. The inlets 8 of the chutes 7 can be located in the center of the shaft 2. When the waste gases enter the shaft 2, a deep vacuum zone is created along the axis of the return cone along its axis, where both the gas flows and the raw materials flowing into the shaft 2 are directed 7. In the central part of the zone of deep dilution, rapid reverse circular flows are formed / contributing to high turbulization of the medium and effective intensification of the processes of mixing and heat exchange between hot gases and raw particles, 4 hp, f-crystals, 4 .

one

The invention relates to the production of building materials, namely, installations for the calcination of cement raw materials in the dry process for the production of cement clinker.

The aim of the invention is to intensify the processes of heat exchange in the furnace shaft heat exchange system.

. FIG. 1 shows a device for heat treatment of a particulate fine material, the general view of FIG. 2 — node 1 in FIG. one; Fig. „3 - embodiments of the reverse cone inserts; in fig. 4 - insert in the form of a hollow open reverse truncated cone with a perforated side surface with a raw material feed chute inserted into it, stereo section.

. A device for heat treatment of its finely dispersed material contains a baking shaft countercurrent heat exchanger 1 and a small continuous shaft 2 placed above it, cyclones-thickeners 3 and a flue 4, connections tangentially lower; shaft section 2 with a rotary kiln 5. Along the axis of the small The drive shaft 2 is fitted with an insert 6 in the form of a reverse cone with a flat base, the diameter of which is 0.3-0.9 of the diameter of the small flow shaft, the height of the cone is 1.5-2.5 times the diameter of its base, and from the upper edge of the heat exchanger and 1 to the base of the cone (insert 6) is 1.0-2.0 of its height. The shape of the surface of the insert 6 — the inverse cone — corresponds to the shape of the inner surface of the small linear shaft 2 at the site of the insert. Insert 6 can be made in the form of a hollow open truncated reverse cone with a perforated surface. The raw material loading chutes 7 of the small straight shaft 2 are located above the base of the reverse cone (insert 6) at a distance of no more than 7 diameters of the base of the cone from it. The inputs 8 of the chutes 7 can be located in the center of the mine 2, The streams 7 of the mine 2 are connected to the sushi-grinding unit 9 of raw materials. By means of the leak 10, the cyclones-thickeners 3 are connected to the upper part of the heat exchanger 1, where the diffusing sheet cone 11 is installed. The rotary kiln 5 is connected to the heat exchanger 1 through the discharge funnel 12 with the pipeline 13.

A device for the heat treatment of bulk particulate material works in the following manner.

Prepared in the drying and grinding unit 9 cement raw materials

the mixture of raw boot chutes 7 enters the small continuous shaft 2 at the site located above the base of the reverse (insert 6). Tangentially injected into the countercurrent heat exchanger 1 through the duct 4, hot (with a temperature of 1000-1) exhaust gases, rotating, pass through the entire height of the heat exchanger 1 towards the raw material being heat-treated 10 for heat treatment. In the upper part of the heat exchanger 1, the rotation of the gas exhaust gases weakens, their temperature decreases to ZOO-ZZO and they are introduced along the shaft channel through the straight channel into the small continuous shaft 2. The purpose of the small linear shaft 2 is the primary heat treatment supplied to it. along chutes 7 cement raw mix: its final drying, partial heating, optimal distribution of raw materials throughout the mine section, forming evenly and effectively re-mixing them with gases, which contributes to an increase in the velocity of particles in hectares Zah, increases the transport capacity of the gas flow and heat exchange performance

mixed gas feed stream with an easily transported gas layer of suspended particles.

The insert 6 is in the form of a hollow cone, which is a poorly streamlined body of the device. An increase in the number of syromas creates a gas stream in the mine behind the insertion of exhausted particles (dustiness) of the gas flow in cyclones-thickeners 3, where it is sent from small

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the low turbulence of the flow, which allows a sharp intensification of the processes of mass and heat exchange of gas with the raw material, significantly improves their mixture formation due to the transition from laminar to turbulent motion of the gas flow. Hot exhaust kiln gases coming into the shaft 2 from the heat exchanger 1 are pushed back by the insert 6 to the walls of the small continuous bed 2, and behind the insert base (reverse cone) a deep vacuum zone is created around its axis extending upwards from the bottom of the shaft Cone at a distance of not more than 7 diameters of its base. The maximum rarefaction of the gas flow is observed in the sections of the shaft 2, located at a distance equal to; 3-4 diameters of the base of the reverse cone. In the zone of deep dilution, in its central part, rapid reverse circular flows are formed, contributing to the high turbulence of the medium and to the effective intensification of the processes of mixing the raw material particles with the hot gas. In the zone of rare-

Line shaft 2. Particles content in gases emitted into the dust-: cleaning system from cyclones-; thickeners, does not exceed 20-30 g / nm. After separation in cyclones, condense 40 bodies x 3 heat-treated in a small one: directing shaft 2, the cement mixture flows through the chutes 10 into the upper part of the heat exchanger 1 and is scattered over its cross section by a cone 11,

4g in the opposite direction of a hot gas stream from below, brought into rotational motion due to its tangential entry into the lower part of the mine with a gas flue 4. Heat-treated

50 in the mine 2, the raw material mixture, coming from the cyclones-thickeners 3 to the heat exchanger 1, first returns back to the mine 2 and the cyclones-thickeners 3 with gas flow, from which it enters the heat exchanger again. This recirculation of the heat treatable raw material after a short time so overloads the gas rtoTOK that the raw particles from

hot gases, and input particles of the raw material, and due to the high turbulence of the gas flow and the vortex of the raw particles, here the most rapid and efficient mixing and heat exchange occurs between the heated raw materials and hot and waste gases. Raw materials are completely dried.

0 is heated to 360-400 ° C and transported to cyclone-thickeners 3.

The feed particles through the inlets 8 of the chutes 7 are fed to the outer boundary of the return flow zone, since, as a result of the high turbulence of the gas flow, it is here that the most rapid shift occurs. The introduction of particles of fungal material with hot exhaust gases. Hot gases completely

0 dry fresh portions of the raw material, evaporate the moisture contained in the raw material, intensively heat the raw particles, contribute to their significant relief, mobility, uniform

increases the rate of movement of particles in gases, increases the transport capacity of the gas flow and the performance of

devices. An increase in the amount of raw particles (dust content) of the gas stream contributes to an increase in the degree of its purification in cyclones-thickeners 3, where it is sent from a small

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gg

Line shaft 2. Particles content in gases emitted into the dust-: cleaning system from cyclones-; thickeners, does not exceed 20-30 g / nm. After separation in cyclones, condense 40 bodies x 3 heat-treated in a small one: directing shaft 2, the cement mixture flows through the chutes 10 into the upper part of the heat exchanger 1 and is scattered over its cross section by a cone 11,

4g in the opposite direction of a hot gas stream from below, brought into rotational motion due to its tangential entry into the lower part of the mine with a gas flue 4. Heat-treated

50 in the mine 2, the raw material mixture, coming from the cyclones-thickeners 3 to the heat exchanger 1, first returns back to the mine 2 and the cyclones-thickeners 3 with gas flow, from which it enters the heat exchanger again. This recirculation of the heat treatable raw material after a short time so overloads the gas rtoTOK that the raw particles from

The smallest weighing capacity of the gases in the heat exchanger 1 begins, in a circular motion, to descend towards the flow of rotating gases. On the way, the raw material mixture is significantly heated to 7VO-810 ° C, dehydrated and partially decarbonized (up to 15-30%). Going down into the lower part of the heat exchanger shaft, it accumulates in the cone discharge funnel 12, from where it is fed to the rotary kiln 5, where the burning and sintering of the mixture ends.

In the proposed design of the device, heat transfer is carried out in countercurrent and in-line methods.

In the countercurrent mode, the raw material is 20 meters of the base of the reverse cone and

particles ground to a size in the prdels of 10-500 microns move towards the flow of more and more hot gases. As the depth of the shaft decreases in intensity of the vortex rotation of the gases fed into the shaft from the bottom, the intensity of their heat exchange with the thermally convertible gas decreases.

In the direct flow method of heat transfer, the raw material mixture is entrained by the gas flow, perceived: its heat from it ..

Performing a poorly streamlined body-insert in the form of a reverse cone - provides the least aerodynamic drag in mine 2 at the site of its location.

The size of the inverse cone, depending on the diameter of the small flow shaft 2, is determined from the conditions of the need to ensure an effective transporting velocity of the gas flow (taking into account the volumes of the product of the combustion of fuel and the allowable under-45 shaft and ensuring the aerodynamic air flow cement industry) in the annular space between the inverse cone and the walls of the shaft 2, equal to 1.3-1.5 of the velocity of heat treatment of particles treated, mainly dependent on their size and their size otnosti. The dimensions of the heat-treatable particles are generally in the range from 1 to 56 500 microns (the presence of particles with a size of 1 mm in an amount of no more than 3% is acceptable). The density of the cement production raw material ranges from

whom resistance in this mine site.

The insertion in the form of a hollow open truncated reverse cone with a perforated surface is necessary if it is used to directly feed raw particles through it for heat treatment along the axis of the shaft to the center of the outer boundary of the zone of reverse rapid flows immediately after the reverse cone edge. The inlets of the squeak chutes can also be located on the outer lateral gra of 2500 to 4000 kg / m, which corresponds to a particle soaring speed in the range from 2 to 10 m / s and, accordingly, the gas flow velocity in the annular space between the walls of the mine and the cone in the range of 2.5 up to 15 m / s.

The location of the reverse cone at the beginning of the small flow shaft at

the area equal to 1.0-2.0 to the height of the reverse cone from the upper edge of the heat exchanger 1., due to the desire to avoid an excessively large height of a small rolling shaft, the value of which is justified, in addition to the area of the reverse cone, also the length of the reverse flow section their turbulence, which does not exceed 7, is located immediately above its base, with the most effective (maximum) mixing of the gas and raw material flows and the intensity of their heat exchange. cone from its base. By the end of the section, equal to 7 diameters of the base of the reverse cone, the intensity of these processes decreases, here the stabilization of the turbulence front of the gas-raw medium is observed, and a further increase in the height of the mine is impractical.

The small straight shaft may not only be cylindrical: its internal cross section may be multifaceted, zigzag-shaped, in the form of an ellipse, etc. Therefore, the external shape of the reverse cone section must also be made in accordance with the internal shape of the cross section of the shaft in which it is located, which contributes to the calculated organization of the gas flow along the installation of the reverse cone

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 mine and the provision of aerodynamic

whom resistance in this mine site.

The insertion in the form of a hollow open truncated reverse cone with a perforated surface is necessary if it is used to directly feed raw particles through it for heat treatment along the axis of the shaft to the center of the outer boundary of the zone of reverse rapid flows immediately after the reverse cone edge. The inlets of the heat chutes can also be located on the outer lateral boundary of the zone of reverse flows when: the introduction of raw leakage into the mine through its lateral surface. .

It is with such methods of introducing raw particles into the mine due to the high turbulence of the gas flow here the most rapid and effective mixing and heat exchange with hot gases occurs.

The proposed design of a device for heat treatment of friable fine material allows reducing fuel consumption for clinker burning and reducing material piping, while increasing the productivity of the cement clinker plant.

Claims (5)

1. A device for heat treatment of a loose, finely dispersed material, mainly a cement raw mix, containing a rotary shaft countercurrent heat exchanger and a small continuous flow shaft with raw feed chutes, located above it, cyclones thickeners and gas ducts, so that the intensification of heat exchange processes in the furnace shaft heat exchange system, it is equipped with 0 five 0 5 o the axis of the small linear shaft with an insert in the form of a reverse cone with a flat base, the diameter of the base of the reverse cone being 0.3-0.9 times the diameter of the small linear shaft, the height of the cone being 1.5-2.5 times the diameter of its base, and the distance from the upper edge of the shaft countercurrent heat exchanger to the base of the cone is 1.0-2jO of its height. 2. A device according to claim 1, characterized in that the reverse cone is made with a surface corresponding to the inner surface of the small linear shaft at the site of the cone location. 3. The device according to claim 1j is characterized in that the insert is made in the form of a hollow open truncated reverse cone with a perforated surface. 4. The device according to claim 1, characterized in that the raw material loading chutes of the small flow shaft are located above the base of the reverse cone, at a distance of not 7 diameters of the base of the cone from it. 5. The device according to claim 3, which is located in that the Inputs of the raw loading chute are located in the center of the small linear shaft. FIG. 2 fig.Z