SU1188493A1 - Layer heat exchanger - Google Patents

Description

The invention relates to devices for cooling bulk materials produced in rotary kilns, for example for cooling cement clinker, as well as for drying and heating bulk materials.

Known grate cooler, in the design of which the grate bars are mounted on a perforated shell, concentric with the housing with a gap, in which inclined partitions are installed, forming air passage channels, through which cooling air from the collector (G) is fed into the grate and material layer.

Closest to the proposed technical essence and the achieved result is a device for distributing the air of the rotating grate cooler, which is equipped with an endless flexible tape, hanging freely on the perforated case of the refrigerator, and a load placed on the hanging part of the tape? The cooling air from the fan through the central air supply device, piping and the protective screen enters the circular space between the inner surface of the flexible tape in the zone of pulling it with the load and the outer surface of the housing and then through the windows the air enters the spacer area. Then, passing a wireless grate, the air enters the zone of the cooled material, and from there - into the furnace.

However, the grate bars and other elements exposed to high temperatures are made of scarce high-alloy heat-resistant steel.

The device is characterized by complexity and low reliability; the presence of the grate Increases hydraulic resistance of the structure.

The aim of the invention is to simplify the design and the intensification of heat transfer.

This goal is achieved by the fact that in a layered heat exchanger containing a rotating body, a device for supplying a gaseous coolant to the layer, loading and unloading parts, a device for supplying a gaseous coolant

in a layer mounted inside the housing along the axis and made in the form of a pipe with a gas supply channel and radial nozzles.

FIG. 1 shows the device, a general view; in fig. 2 shows section A-A in FIG. 1, (cross section of the central tube; FIG. 3 is a section B-B (cross section of radial nozzles).

The heat exchanger is connected to the discharge end of the furnace 1 by means of a cone junction. At the place of transferring burned material from the furnace to the heat exchanger, threshold sorter plates 2 are made of heat-resistant material. Inside the housing 3 there is a fixed central tube 4 concentric to it, open from the cold end, inside of which there is an air supplying manifold 5. At the bottom of the collector, radial nozzles 6 open below, mounted towards the segment layer of the material and immersed in a small depth (100-150 mm).

The case of the heat exchanger '3 is protected from high temperatures by lining 7, which can be made of οι-resistant brick or metal plates. In the discharge part of the heat exchanger, a sorting grid 8 is provided, through the lower part of which the cooled material is discharged, and through the upper one excess gas is removed in the direction indicated by arrow 9. The stationary central pipe 4 located inside the housing 3 has a lining layer 10 on the outer surface and is fixed to foundation through the support node 11. Inside the pipe is fixed nozzle 12, through which fuel is fed into the rotary kiln.

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From the open side of the fixed central pipe 4, air is injected into the air intake manifold, as indicated by arrow 13, and water for evaporative cooling is supplied through pipe 14 to one of the branch pipes 15. The discharge head 16 is equipped with chutes in the lower part to discharge the cooled material to the conveyors 17. Arrow 18 shows the direction of rotation of the heat exchanger body and the furnace.

The heat exchanger works as follows

in a way.

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The calcined bulk material from the furnace 1 enters the heat exchanger through the sorting threshold plates 2, which are provided with openings that are necessary for holding the largest pieces in the furnace until they are self-grinding when the material is continuously being poured and rolled in the furnace. The targets in the slabs are of such dimensions that the size of the pieces of material passing through them does not exceed 100-150 mm.

The material that has passed through the plates drops in the space between the heat exchanger body 3 and the fixed central tube 4, where it forms an erratic layer of bulk material moving due to the rotation of the heat exchanger to its unloading part. At the same time, the calcined bulk material passes successively through the radial nozzles 6, being cooled by air coming from the radial nozzles 6 through the thickness of the material layer to the surface of the slope of the rolling layer. The total flow area of the radial nozzles 6 is chosen so that the speed of the cooling air at the entrance to the layer of material and at the exit from it is within acceptable limits. To ensure the necessary operational durability, the radial nozzles 6 located in the hot zone must be made of a heat-resistant material and have the required wall thickness.

The radial nozzles 6 in cross-section have a streamlined shape with pointed front and rear faces (Fig. 3), which ensures their better flow around with a layer of material moving in the rolling layer.

The location of the radial nozzles relative to each other and with respect to the rotating body should ensure the passage and pouring of lump material between them.

In order to adjust the adjustment of the amount of air supplied to each nozzle, they can be equipped with gates.

Since the amount of cooling air is equal to the amount of secondary air going to burn, and since this amount of air in some cases is not enough for complete

cooling the material (up to about 100 ° C), then evaporative cooling is provided in the heat exchanger with water entering the material through the nozzle 15. Water vapor is removed from the heat exchanger through the nozzle in the discharge head 16, as indicated by arrow 9.

The amount of water and its supply system must ensure that the material exits the cooler without waterlogging.

To ensure the movement of material along the cooler, its body has an angle of inclination to the horizon, equal to the angle of inclination of the kiln. In necessary cases to increase the transporting capacity of the case. the heat exchanger can be made tapered with expansion in the direction of discharge.

The diameter of the fixed central pipe 4 should be chosen so that the furnace operator could enter it to observe the process of firing the material in the furnace and adjust the fuel nozzle. In order to ensure comfortable working conditions in the central pipe, it can be provided with a ventilation and air conditioning system.

The device can be made integral with a rotary kiln or as a separately installable unit. It can also be used for heating and drying bulk materials. At the same time, it is enough to supply the heated gas, rather than cold air, through the central tube and the pipes to the layer of material.

The heat exchanger of the described design allows for highly efficient heat transfer in the layer between the lump material and the gaseous heat — or coolant. At the same time, the design is significantly simplified, the metal consumption is reduced, the laboriousness of manufacturing and repairs is reduced, the position of the air inlets relative to the material segment layer is simplified, the consumption of deficient heat-resistant materials is reduced, the use of additional cooling of the burned material with water can be significantly reduced; significantly increases the operational reliability of the structure. Used

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In addition to using a heat exchanger for heating and drying the material, the size and intensity of the metal are significantly reduced compared with the known drying drums, there is no need for complex and numerous transfer devices, the heat technical efficiency rises, the specific heat consumption for the material is reduced.

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Fig.Z

Claims (2)

LAYER HEAT EXCHANGER, 'containing a rotating body, a device for supplying a gaseous coolant to the layer, loading and unloading parts, which are designed to supply the gaseous coolant to simplify the design and intensify heat exchange the layer is mounted inside the body along the axis and is made in the form of a pipe with a gas supply channel and radial nozzles. ' FIG. 7 "about to* 00 00 > one I188493 2