CS198141B2 - Method of and apparatus for manufacturing sintered products - Google Patents

Abstract

1463393 Cement manufacture ZEMENTANLAGENBAU DESSAU VEB 14 March 1974 [31 May 1973] 11466/74 Heading C1H [Also in Division F4] In making a sintered product (such as cement clinker) a liquid fuel is absorbed in a part of the raw material to be sintered. As shown, raw material from a bin 11 and liquid fuel from a preheater 10 are mixed and granulated or pelleted at 12. The granules are fed through a preheating stage 3 to a combustion chamber 2 above a fluidized sintering bed 1. Combustion air 15 passes upwardly through the bed 1. In the combustion chamber 2, the liquid fuel in the granules vaporizes and is ignited. The granules burst to form particles. An eddying zone is formed above the bed 1. Raw material to be sintered is also supplied to the apparatus through feed pipes 14. As this material passes towards the bed 1, it is preheated by upwardly flowing hot gases. This preheated material, when it reaches the eddying zone, agglomerates with the particles therein. The agglomerated particles then drop on to the fluidized sintering bed 1 where their thermal treatment is completed. This forms a layer of sintered particles which due to their weight are at rest. These sintered particles are discharged through a shaft cooler 17 where the incoming combustion air 15 is heated. In a modification, a binder or a solid fuel is added to the mixture of raw material and liquid fuel.

Description

(54) A method for manufacturing sintered articles and apparatus for performing the method

The invention relates to a process for the production of sintered products, in particular cement clinker on a sintered bed, by supplying liquid fuel bound to granules and to an apparatus for carrying out the process.

It is known to granulate finely ground raw materials with the addition of water and solid ground or granular fuels and then to undergo heat treatment. In the production of cement clinker, such a process is referred to as a black meal process.

In general, the quantities of raw material and fuel required for the production process are granulated or pelletized. In particular, this process is carried out in shaft furnaces or on sintering belts.

The disadvantage of this method is that the water required for binding or the residual moisture remaining in the raw material must first be evaporated, and that the evaporation heat must be regarded as a heat loss.

Further, it is known to apply solid ground fuel to the surface of the granules. This is done to prevent unwanted discoloration of the cement with carbon. In a further heat treatment, especially on a movable grate or in a shaft furnace, the disintegration of the granules leads to undesirable side effects and to a partial de-mixing of the charge.

In the production of cement clinker by a wet process, it is known to dewater raw sludge and to reinforce it before dewatering in order to prevent dewatering. This reinforcement is achieved by the slight addition of a high viscosity oil. in an emulsion. Coal suspensions, resp. mixtures of oil emulsion and coal emulsion. However, these proportions of fuel are so small, for example 2%, that these proportions have only an insignificant effect on the firing process.

It is known to use rotary kilns as firing aggregates. A disadvantage here is the high rotational stress of the lining. Large circulating masses require a lot of energy to drive and a large furnace volume produces less specific heat intensity for this firing unit.

Further, it is known to pre-heat a rotary kiln to utilize flue gas heat and to heat raw material. The highest specific heat consumption occurs in the case of high pre-heating temperatures in the case of cement raw meal. The open flame heat delivery method in a rotary tube furnace does not produce any optimal heat delivery where it is effectively needed. Furthermore, in the region of the preheater, the heat transfer does not emit heat by the shining flame under thermally favorable conditions, but by contact with the hot gases.

It is further known to cool the fired cecent clinker in the clinker coolers connected downstream of the rotary tube furnace while heating part of the combustion air. The disadvantage of these cooling units is either the circulating masses or the highly stressed parts of the cooling units with cooling grates.

The purpose of the invention is to increase the thermal efficiency of this method by optimally supplying heat at locations and areas of highest heat consumption and reducing radiation losses, as well as increasing operating times and lowering investment costs by simplified machine design and increased lining life by removing rotating aggregates.

SUMMARY OF THE INVENTION The object of the present invention is to achieve by decanting the fuel in a portion of the raw material of the sintered bed, to partially crack the granules above the sintered bed to create a fluidized bed in which the raw material particles agglomerate and partially sinter. of the heat required for calcination, in the preheating system to preheat the freshly introduced raw meal in order to exploit the heat of the exhaust gas, and to preheat the combustion air in the cooling unit.

In this case, a sintered bed is to be produced by the introduced fuel granules and by the agglomeration of the clinker cores, without the heat loss of the binders (water) being supplied by the evaporation heat.

According to the invention, this is achieved by feeding the fuel granules directly to the sinter bed, fresh raw meal to the preheater, and the finished material formed on the sinter bed being fed to a cooler, for example a shaft cooler.

According to a preferred embodiment of the invention, the fuel granules are produced from liquid fuel and, if necessary, a binder that does not require evaporative heat and / or a portion of the solid fuel is added to these granules.

According to another embodiment of the invention, the split amount of raw material into fuel granules and fresh raw meal is adjustable to adjust the process for a variety of production conditions.

According to an advantageous embodiment of the invention, a firing space and one or more parallel preheaters, which consist of one or more preheating stages, which are preferably provided with tapered cross sections at the transition points, are connected upstream of the sintering bed, and the preheating stages are combined with co-current stages. connected to each other via riser pipes and material return pipes, and the supply of granules formed in the mixing aggregate is introduced into a preheating stage or firing chamber and a feed device for fresh raw meal is placed in the riser pipe.

The invention is explained in more detail below by way of example with reference to the drawing.

The processing device is schematically illustrated. 1 shows a front view and FIG. 2 shows a side view of the device according to the invention.

The fuel or fuel mixture is so preheated in the preheater 10 that the viscosity required for the process of the invention is achieved. The preheated fuel is fed to the mixing unit 12. Into this mixing unit 12 comes from the raw material silo 11 a metered allocation of the raw material at various points in the mixing path until the necessary consistency for granulation or pelleting is achieved. The mixing unit 12 is connected to a suitable granulating or pelletizing device. The feeding device 13 is fed to the preheating stage 3. It is also possible to feed at other points of the system, for example to the firing chamber 2.

The granules are ignited on the sintered bed 1, partially broken up during the gasification and formed in the firing chamber 2 a whirling layer formed by the sintering cores.

It is already known to preheat the raw material in a controlled, upstream counter preheating. The raw material is fed through the insertion points 14 into the riser pipe 8. It is preheated in the preheater, which consists of preheating stages 3 and 4, cyclones 5 and 7, as well as riser pipes 6 and 8, exhaust air ducts and 18 return of material. The preheating stages 3 and 4 are provided with tapered cross-sections at the transition points. The preheater is adjusted so that no deposits are formed in the cyclones 5 and 7, especially at their tips.

With the hot gas, the solid particles are entrained from the sintered bed 1 into the firing space 2 and into the preheating stages 3 and 4.

Preheated raw meal is deposited on these cores. By their own weight at the corresponding mass, they are carried out from the preheating stage 3 into the firing chamber 2 and deposited in the sintered bed 1. In the case of cement raw meal, calcination already occurs in the preheating stage 3 and in the firing chamber 2. Since this process requires a high heat load, a favorable heat supply takes place in the flame zone in the firing chamber 2.

Above the sintered bed 1, a fluidized bed is formed in the firing chamber 2. Further agglomeration and partial sintering are carried out there. The sinter bed 1 is sized so that the final formation of clinker minerals takes place therein.

In the downstream cooling unit 17, for example in the shaft cooler, o198141 occurs

6 heating the combustion air 15 and cooling the finished product 16.

The processing device consists of a sintered bed 1, a firing space 2 located above it and a connected preheating system consisting of one or more preheaters arranged in parallel. A two-stream arrangement is shown by way of example.

The formation of fuel granules is carried out in the mixing unit 12, to which the fuel from the preheater 10 and the raw material from the silo 11 of the raw material are fed. The mixing aggregate includes a pelletizing or pelletizing device and a feed device 13.

Downstream of the sintering bed 1 is a shaft cooler 17 with discharge devices for delivering the finished product and for supplying combustion air 15.

Claims (4)

SUBJECT OF THE INVENTION Method for producing sintered products, in particular cement clinker on a sintering bed, by supplying liquid fuel bound to the granules, characterized in that the fuel granules are fed directly to the sintering bed, fresh raw meal is fed to the preheater and finished material formed on the sintering The bed is led to a cooler, for example a shaft cooler. Method according to claim 1, characterized in that the fuel granules are produced from liquid fuel and a part of the raw material and that, if necessary, a binder which does not require evaporative heat and / or a part of the solid fuel is added to the granules. 3. A method according to claim 1 or 2, characterized in that the distribution of the amount of raw material into fuel granules and fresh raw meal is adjustable to adjust the method for a variety of production conditions. Device for carrying out the method according to Claims 1 to 3, characterized in that above the sintered bed (1) there is a firing space (2) and one or more preheaters arranged in parallel, which consist of one or more preheating stages (3, 4). which are preferably provided with tapered cross-sections at the transition points, and the preheating stages (3, 4) are combined with co-current stages, for example cyclones (5), connected to each other via risers (6) and material return pipes (18), and the feed (13) of the granules formed in the mixing unit (12) is introduced into the preheating stage (3) or into the firing space (2) and the feed device (14) for fresh raw meal is placed in the riser (8) .