SU1475947A1 - Method of extarnal heating of sinter cake charge - Google Patents

Abstract

The invention relates to the preparation of iron ore raw materials for blast furnace smelting, specifically to agglomeration, and can be used in the metallurgical, chemical and building materials industries. The purpose of the invention is to reduce energy costs. During sintering of the sinter on the sintering machine, ignition of the charge is carried out with external heating with temperatures in the heating, holding and cooling zones equal to 800-1200, 1150-1300 and 600-700 ° C, respectively, with the residence time of the cake in these zones being 25-30 , 35-45 and 30-35% of the ignition time. 40-45% of the combustion products of the gas, which are replaced with air containing 21% oxygen, are removed from the holding and cooling zones. In this case, a significant reduction in the cost of sinter is achieved compared with the supply of technical oxygen to the forge. 3 ill., 1 tab.

Description

one

The invention relates to the preparation of iron ore raw materials for blast smelting, specifically to agglomeration, and can be used in the metallurgical, chemical industry of building materials.

The purpose of the invention is to reduce energy costs.

The increase in the oxidizing potential of mountain gases is carried out by replacing combustion products containing high levels of CO and atmospheric air containing up to 21% O g. In this case, the correspondence between the number of gases produced in the combustion space and the gas permeability of the charge is not disturbed.

Atmospheric air is supplied to the working space of the furnace by parallel flows with displaced axes, which makes it possible to create circulation zones (Fig. 1) to improve the mixing of flue gases with secondary air, eliminate stagnant zones between the burners, level the temperature of the lit surface and gas flow turbulence. All these factors to a certain extent allow to intensify the combustion of solid charge fuel, improve heat transfer, and also increase the value of maximum temperatures in the sinter layer.

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The selected replacement limits (40-45%) of flue gases with an equivalent amount of atmospheric air are explained as follows.

It has been established that the chemical completeness of the combustion of carbon of a solid fuel with an oxygen content in the flue gases in excess of 14% becomes the same as during the combustion of carbon in an atmosphere of air, i.e. From this point of view, the optimal value should be considered 13-14%.

When 35% of the products of combustion are removed from the incendiary horn and their replacement by an equivalent amount of air, the oxygen content in the furnace gases is slightly less and will be 12.5%. As shown by chemical analysis of mountain gases, the degree of use of thermal energy of carbon solid fuel in this case is lower.

Content Oz. in mountain gases the following,%: 12.5, 13.68.

The composition of the aglogas,%: CO g 23,12; 23.14; 022.22; 2.63; CO 1.68; 1.47; CO: C02 0.072; 0.063.

When 50% of the flue gases are removed from the incendiary horn and they are replaced by atmospheric air, the ignition temperature decreases with increasing oxygen content and, as a result, the quality of the agglomerate deteriorates.

The proposed method of external heating is carried out as follows.

Figures 2 and 3 show the forge 1 of the sintering machine, including gas burner 2, injection 3, and air inlet 4 devices. Injecting devices can operate on both compressed and ventilating air and are mounted in the roof or in any free side wall of the incendiary horn. Air intake devices are nozzles installed in the side walls of the tangential axis of the burners.

The ignition is as follows.

The sintering carts 5 load the sintering mixture 6. The sintering carts pass under the mountain 1, where the mixture is heated to ignite the carbon of the solid fuel (Fig. 2, zone A), extract (zone B) and cool the Xzone C spec). In this case, the temperature of the coolant in the heating zone of the charge is from 800–900 to 1150–1300 ° C and

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in the cooling zone, it is reduced to 600 C. During the external heat treatment of the charge in zones B and C, 40-45% of the waste products removed from the furnace space are replaced with an equivalent amount of atmospheric air containing up to 21% of oxygen blown through the nozzles ,

To compare the proposed method of external heating with the known on the sintering machine, pilot tests were carried out. The tests were carried out in two periods: the 1st with the supply and distribution of technical oxygen in the process zones, II — with the replacement of the combustion products removed from the furnace space with an equivalent amount of atmospheric air.

The test results are shown in the table.

According to the above data, external heating of the charge according to the proposed method in comparison with the known method allows to increase the productivity of the sinter machine by 1.5%, reduce the fines content in the sinter by 1% and reduce the consumption of solid fuel by 0.5 abs.%.

Claims (1)

Since air is used instead of expensive oxygen, a significant reduction in energy costs and the cost of sinter is achieved. Invention Formula The method of external heating of the sintering mixture, including the use of oxygen-containing coolant, filtered through a layer with a temperature increased in the heating zones of the charge from 800–900 ° C to 1150–1200 ° C, maintained in the holding zone in the range of 1150–1300 ° C and reduced in the zone of cooling, the specimen is up to 700-600 ° C with the residence time of the layer in the zones of 25-30, 35-45 and 30-35%, respectively, of the ignition time, o.t.l and h a rant, and so that, in order to reduce energy costs, 40-45% of the combustion products are removed from the holding and cooling zones and replace them with equivalent tny amount of atmospheric air. i Table continuation Natural consumption gas to the horn including Zones, m3 / h 800 A300 B400 B100. Air flow on the forge, m3 / h 13,000 Oxygen consumption by zones, m3 / m3 heat carrier A0.02 B0.05 B0,03 Total consumption oxygen on horn, m3 / h500,54 The amount of injected flue gases from 1000 ° C, m3 / h Atmosrer-sh80z & oh / Basics r & o The amount of injected atmospheric air in zones B and B, m3 / h - 4200 The content of free oxygen in the mountain gases by zone,%  A11.2 10.6 B14.6 13.3 B12.8 15.9 The content of the little things (less than 5 mm) in sinter,% 14,12 13,12 Specific performance sintering machines, t / m2-h 1.576 1,599 Specific fuel consumption per charge, kg / t sinter 42.0 41.79 Circulation / Zone cpt / p.f 2 L - X -her ... Y / S // S / J ///// S //// S &///////; S / ;;;; JJ  I and with "g of with with f r lay I., rfrrrrrr ay I ii of 9%-/, / ... S &///////; S / ;;;;