RU2275435C1 - Method for igniting agglomeration charge moving on sintering cars - Google Patents

Abstract

FIELD: preparation of charge by agglomeration.

SUBSTANCE: method comprises successive steps realized in respective zones by action of heat of gas combustion, namely: heating charge, igniting it and heating cake. Gas is combusted only under crown of igniting zone in burners while supplying heated air. Air supplied to burners is heated by heat of outer surface of crown of igniting zone having refractory blocks placed closely one to other; each refractory block is provided with burner. Surface area of block turned inside igniting zone is 500 x 500 mm. Air supplied to burners for gas combustion is heated in air duct mounted under crown of igniting zone and having housing whose lower flat surface corresponds to outer surface of igniting zone crown and it is approached to it as much as possible. Charge is heated under radial arch with volume of working space increased along motion direction of sintering cars.

EFFECT: energy saving process of igniting agglomeration charge, lowered gas consumption for igniting it and minimized heat quantity for heating charge.

4 cl, 1 dwg

Description

The invention relates to the preparation of raw materials by agglomeration and can be used in the metallurgical and chemical industries, as well as in the production of building materials.

The economic prerequisite for creating new methods for the ignition of the sinter charge, characterized by a sufficiently high fuel consumption, is the continuous rise in the cost of energy and an increase in the share of the fuel component in the cost of production.

Known for the horn (SU 244351, publ. 1969) / 1 / for the implementation of the method of ignition of the charge, according to which the lining of the vault of the furnace is cooled by air and heated air is fed into nozzles for burning fuel.

To cool the lining over the entire surface of the forge between the lining and the casing, spiral tubes are installed on the heat-conducting backfill.

The surface of the forge arch has a different lining temperature.

The location of the pipes over the entire surface of the forge arch leads to a decrease in the temperature of heating the air.

The supply of air with a reduced temperature to the nozzles of the hearth reduces fuel savings on ignition of the charge.

Closest to the claimed is a method of ignition of the sinter charge according to patent RU 2229665/2 /.

The known method / 2 / includes heating the charge, ignition and heating the cake, carried out sequentially in the respective zones by heat from burning gas, while the gas is burned only under the arch of the ignition zone in the burners using heated air.

The air is heated in the volume of the main chamber in the collectors made in the form of transverse vaulted beams of box section, ending with a heat-absorbing surface facing the inside of the chamber.

Thus, the air supplied to the burners is heated by heat from the combustion products of gas fuel and heat from the radiation of burning solid fuel particles located in the upper part of the charge layer, i.e. due to heat removal from the main chamber.

As a result, in the case of using all the heated air in the burners of the ignition zone, the gas flow rate is unlikely to decrease significantly, and in the case of transferring part of the heated air to additional chambers fenced off from the main by separation walls, the gas flow rate can increase.

In addition, the transverse vaulted beams do not completely overlap the surface of the roof of the main chamber and part of the surface of the ignition roof becomes a source of heat loss.

The present invention is the creation of an energy-saving and simpler method of ignition of the sinter charge.

To solve this problem, the method of ignition of an agglomeration charge moving on sintering trolleys involves heating the mixture, actually igniting and heating the cake, carried out sequentially in the respective zones by heat from burning gas, while gas is burned only under the arch of the ignition zone in the burners with heated air, and the air supplied to the burners is heated with heat from the outer surface of the roof of the ignition zone, which consists of completely collected refractory blocks, each of which is equipped with a burner.

To ensure uniform ignition of the charge without excessive pressure of the combustion products in the ignition zone, the surface area of the block facing the inside of the ignition zone is 500 × 500 mm.

For the beneficial use of the heat of the roof, the air supplied to the gas burners is heated in an air duct installed above the roof of the ignition zone, the lower flat surface of the housing of which corresponds to the outer surface of the roof of the roof of the ignition zone and is as close as possible to it.

The mixture is heated under a radial arch adjacent to the ignition vault with a working space volume that increases along the movement of the sintering trolleys.

The essence of the new method of ignition of the charge is as follows.

In the inventive method, the air supplied to the burner is heated with heat from the outer surface of the roof of the ignition zone, which consists of completely assembled refractory blocks, each of which is equipped with a burner.

In this case, the air is heated in an air duct mounted above the roof of the ignition zone, the lower flat surface of the casing of which corresponds to the outer surface of the ignition vault and is as close as possible to it.

As a result, heat is used to heat the air, which passed through the refractory arch of the highest temperature zone, characterized by maximum heat loss, and could be lost permanently.

Thus, the heat required for ignition of the charge remains unchanged, and the supply of heated air to the burners reduces the gas flow in the ignition zone and provides heat to the other two zones, unheated by gas: heating the mixture and cake.

In the first zone, the charge is heated under a radial refractory arch adjacent to the ignition vault with a working space volume that increases along the movement of the sintering trolleys.

This allows you to smoothly increase the surface temperature of the mixture from the initial to the ignition temperature of solid fuel with a minimum heat consumption for heating and the practical absence of heat loss through a refractory arch having a low surface temperature.

In the last zone, it is also possible to heat the cake under a refractory arch, which prevents the emission of heat from the surface of the ignited charge and the access of cold air to it.

Due to this, the heat treatment of the surface of the cake can be carried out at the minimum cost of heat coming from the ignition zone.

The rational use of heat in the working space of the ignition zone inevitably leads to a decrease in fuel consumption for the process of ignition of the charge.

A new technical result achieved by the invention is to reduce the gas consumption for the actual ignition and minimize the heat required to heat the mixture.

As a result, the new method does not require gas supply at the stage of heating the mixture and heating the cake and can significantly reduce the consumption of gaseous fuel for the ignition process as a whole.

The method is illustrated in the drawing, which shows the zone of the process of ignition of the charge.

Zone I corresponds to the charge heating zone, zone II to the ignition zone itself, zone III to the cake heating zone.

The heating of the charge layer moving on the sintering trolleys is carried out in zone I under the arch of the refractory radial arch 1, which is initially 30-50 mm from the upper edge of the side of the sintering trolleys.

Gas is burned in burners of 2 zones II. The burners are mounted on the casing of the air pipe 3, the lower flat surface 4 of which is located at a distance of 50-100 mm from the outer surface of the refractory blocks 5, forming a continuous arch of the ignition zone.

The air pumped into the air duct housing takes away heat from the lower flat surface of its housing and enters the burners.

In this case, the temperature of the surface of the air duct body facing the surrounding space is close to the ambient temperature.

The surface area of each burner unit facing the ignition zone is 500 × 500 mm. This size is a multiple of the grate area of the sintering trolleys of sinter machines of different sizes and convenient for the rational placement of burners and to ensure uniformity of ignition. To optimize the volume of the working space of the ignition zone, the charge is actually ignited under the arch, the inner surface of which is 500-700 mm from the surface of the ignited charge layer.

With a smaller value of this distance, the likelihood of chemical destruction of the arch refractories increases due to the possible ingress of particles of iron and calcium oxides formed during the explosive destruction of fluxes, sludges, scale and some concentrates containing hydrated moisture and carbonates.

Increasing this distance will result in heat loss through the side walls of the roof.

Sinter heating is carried out in zone III under a refractory arch, which prevents the emission of heat from the surface of the ignited charge and the access of cold air to it, with minimal expenditure of heat coming from the ignition zone.

Thus, in contrast to the prototype method, the claimed method due to the optimization of the use of gaseous fuel is less energy intensive and at the same time more simple.

Claims (4)

1. The method of ignition of an agglomeration charge moving on sintering trolleys, including heating the mixture, actually igniting and heating the cake, carried out sequentially in the respective zones by heat from burning gas, the gas being burned only under the arch of the ignition zone in the burners with the supply of heated air, characterized in that the air supplied to the burner is heated with heat from the outer surface of the roof of the ignition zone, which consists of completely collected refractory blocks, each of which is equipped with a burner. 2. The method according to claim 1, characterized in that the charge is actually ignited under the arch of the zone, consisting of completely recovered refractory blocks, while the surface area of the block facing the inside of the ignition zone is 500 × 500 mm. 3. The method according to claim 1, characterized in that the air supplied to the burner for burning gas is heated in an air duct installed above the arch of the ignition zone, the lower flat surface of the housing of which corresponds to the outer surface of the arch of the ignition zone and is as close as possible to it. 4. The method according to claim 1, characterized in that the charge is heated under a radial arch adjacent to the arch of the ignition with a working space volume that increases along the movement of the sintering carts.