RU2028988C1 - Process of production of cement clinker - Google Patents

Abstract

FIELD: construction industry. SUBSTANCE: process of production of cement clinker involves grinding of raw components, preparation of two mixtures (one being clinker fuel-containing), granulation, feed to conveyer grid first clinker fuel-containing mixture granules, then sinter mixture granules, size 10.0-15.0 mm with content of solid fuel between 4 and 6%. Height of layer of sinter mixture is 50-100 mm whereas height of two layers amounts to 360-400 mm. This process is followed by annealing. Laying of granules of sinter mixture in upper low-temperature layer and granules of clinker mixture in lower high-temperature layer provides for temperature in layer of clinker mixture necessary for formation of clinker which excludes necessity of return of clinker for new annealing and provides for 2.0-2.5-fold increase of specific output of finished product and for enhanced efficiency of process. Losses of heat diminish in this case by 5-10 %. EFFECT: increased output of finished product, diminished heat losses. 3 tbl

Description

 The invention relates to the construction materials industry and can be used to produce cement clinker and agloporite gravel.

 A known technology for producing cement clinker, including grinding of raw materials and feed fuel, their dosing, mixing, moistening, granulation and subsequent firing on a conveyor belt.

 The disadvantages of this method are the large specific heat consumption for the production of clinker, which is 1700 kcal / kg of clinker, as well as low specific productivity of the conveyor lattice.

 A large heat consumption is associated with an uneven distribution of heat along the horizons of the charge. The low specific productivity of this method is due to the need to return the unfired clinker of the upper horizon of the charge, which is 40% of the finished product. The imperfection of the upper horizons of the clinker charge is mainly due to the insufficiently high temperature in these upper sections of the charge layer. In the lower horizons of the charge, heat loss is associated with incomplete combustion of the charge fuel. The lower horizons of the mixture are fired with excess heat. Under the influence of high temperature, over-melting of the charge occurs. The melt flows to the underlying sections of the charge and, enveloping the granules, makes it difficult to burn the charge fuel in them.

 The closest in technical essence and the achieved result to the invention is a method for producing cement clinker.

 According to the known method, to the sludge obtained by grinding the raw materials, moistening them, add 125-135% return, which allows you to get the moisture content of the granules 12-14%. On the conveyor grill above the bed is a layer of granules that do not contain solid fuel, and then a layer of granules with fuel.

 Gases from the upper layer are used to prepare the material in the lower layer. Material from the lower layer gets into the return, which is subjected to secondary firing, while placing it in the upper layer.

The disadvantages of this method are the large specific heat consumption (1630 kcal / kg cells) and low specific productivity (330 kg / m ² ) due to a significant amount of return: in addition to the upper horizons of the charge, the entire lower layer of granules of the clinker charge, not containing fuel, is returned to re firing, i.e. the finished product is obtained only from the middle horizons of the charge.

 The aim of the invention is to reduce heat consumption and increase productivity.

 This is achieved by the fact that in the inventive method for the production of cement clinker, including grinding raw materials, preparing two charges, one of which is fuel clinker, granulation, layer-by-layer feeding of granules onto a conveyor belt with subsequent firing, as the other charge use agloporite with a content of 4-6 % of solid fuel, moreover, the agloporite charge is laid in a layer of 50-150 mm on the clinker charge layer with a total height of two layers of 350-400 mm, and granules from the agloporite charge are formed with a size of 10-15 mm.

 Thus, in the present invention, as the agglomerate mixture is fired, drying, heating and firing of the clinker charge occurs.

 First, a layer of pellets of a clinker fuel-containing mixture is fed to the conveyor grill, and on top, where the firing temperature is lower, a layer of granules of an agloporite mixture provides optimal conditions for firing each mixture and allows to obtain a finished product yield close to 100%, excluding their return to re-firing , which reduces specific fuel consumption and increases specific productivity. The choice of granules of agloporite mixture with a size of 10-15 mm allows you to stretch the firing zone, i.e. firing will occur in a significant amount at the same time, and this will speed up the process.

 Reducing heat consumption and increasing productivity in the present method are also due to the high degree of heat recovery and the intensity of clinker formation.

Ensuring the temperature required for clinkering (1700 ^C) is carried out in the proposed method by utilizing heat from the fuel in the combustion zone and the charge agloporitovoy cooling calcine agloporitovoy batch, the percentage of a recovered heat increases with increase in height of layers batches. In addition, there is an intensification of the clinker formation process due to the formation of a zone of elevated temperatures inside the charge layer, rapidly moving in the direction of air suction.

 A content of solid fuel in an agloporite charge of less than 4% does not provide a degree of heat recovery and heat transfer from an agloporite charge to a clinker charge necessary to achieve a clinker formation temperature.

 An increase in the solid fuel content in an agloporite charge of more than 6% leads to an unjustified increase in heat consumption, as well as sintering of granules of an agloporite charge, i.e. receiving agloporite instead of agloporite gravel.

 When the layer height of agloporite granules is less than 50 mm, the degree of heat utilization and heat transfer from the agloporite mixture to the clinker is not ensured to achieve a clinker formation temperature in the upper horizon of the lower layer of the clinker charge. In addition, the top layer of agloporite granules is a protective shield from the thermal shock of clinker granules, which provides a gentle mode of heating, preventing their destruction.

 When the height of the layer of granules of the agloporite charge is more than 150 mm, the proportion of clinker charge on the conveyor lattice decreases and thereby decreases the productivity of the clinker firing process.

 The granule size of an agloporite charge of less than 10 mm reduces the gas permeability of the charge and thereby reduces productivity.

 When the granule size of an agloporite charge is more than 15 mm, the heat transfer intensity decreases and heat loss increases.

 PRI me R 1. Prepare a raw material mixture to obtain a clinker charge by co-grinding the raw materials,%: limestone 63, tails wet magnetic separation. Kachkanar mining and processing plant 27, coke 9. Molded granules of 7 mm in size from a raw mix on a plate granulator.

 A raw mix is prepared to produce an agloporite charge by co-grinding the raw components,% ash 87 of the Reftinskaya state district power station, clay 8, coal 5. Granules from 10 to 15 mm are formed from this mixture on a plate granulator. Pellets of burnt clinker ("bottom bed") are placed on the grate, protecting the grate from the action of high temperature. Clinker charge granules are fed in layers to the lower layer, agloporite charge granules to the upper layer. Pellet firing is carried out on a semi-industrial installation.

For ignition use flue gases of the incendiary hearth, temperature 1300 ^о С, duration 6 min

 Firing products: clinker and agloporite gravel obtained in different layers are separated using a metal sheet mounted horizontally at the interface.

 In the remaining examples, the technology for preparing raw mixes and firing granular charges is similar to that described (see tab. 1, 2, 3, examples 1-13), except for example 14 of the table. 3, in which the raw material mixture is prepared and fired according to the prototype: the mixture 1 is prepared by co-grinding the raw material components,%: limestone 63, tails of wet magnetic separation of the Kachkanarsky GOK) 27, coke 15; prepare the charge 2 also, but without turning on solid fuel. Granules from 5 to 10 mm in size are formed from each mixture individually on a plate granulator. A "bottom bed" is laid on the grate, on which granules of a clinker charge 2 without fuel content of 100 m high, half diluted with a half-burn, are laid, granules of a clinker fuel-containing mixture 250 mm high are placed on top.

Using the invention provides the following technical and economic advantages:
increase in specific productivity by 2-2.5 times;
5-10% reduction in specific heat consumption for firing;
obtaining two finished products of high quality firing: agloporite gravel with a bulk density of 630 kg / m ³ , compressive strength of 3.0 MPa; cement clinker with a tensile strength of 42.1-45.6 MPa.

Claims (1)

 METHOD FOR PRODUCING A CEMENT CLINKER in a grate furnace, comprising sequentially supplying annealed clinker material to the conveyor grate to form a bed, a granulated fuel-containing clinker mixture to form a middle layer and a raw material mixture to form an upper layer, while the height of the middle and upper layer is 400 - 350 - mm, and firing, characterized in that as a raw material charge for the formation of the upper layer using agloporite charge with a grain size of 10 to 15 mm, while Size height agloporitovoy mixture layer is 50 - 150 mm and after firing resulting in different layers of cement clinker and gravel algoporitovy separated.

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