EA008155B1 - Method for igniting sintering mixture transportable on sintering trolleys - Google Patents

Abstract

A method for igniting ore sintering, the method comprises heating of the mixture, in zone I, ignition in zone II and heating the cake in zone III. To realize the method heat is used after gas burning, the gas is burnt in burners in zone II arranged on the airway 3 housing. The roof of zone II is an integral structure made of refractory blocks 5. The burners 2 are arranged in blocks 5, the flat surface 4 of the airway 3 is distanced by only 5-100 mm from the blocks 5 outer surface and takes off its heat which, otherwise, could be lost. Heat from surface 4 is used to heat air in the housing 3, the heated air is supplied to burners 2, which leads to gas consumption decrease used for ignition of the sintering mixture.

Description

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

The economic prerequisite for the creation of new methods for the ignition of the sintering mixture, which is characterized by relatively 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 horn (8I 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 hearth is cooled by air and heated air is fed to the nozzles for burning fuel.

To cool the lining over the entire surface of the vault of the hearth between the lining and the casing on the heat-conducting backfill spiral-shaped pipes are installed.

The surface of the forge has a different lining temperature.

The location of the pipe over the entire surface of the vault of the hearth leads to a decrease in the temperature of air heating.

Air supply with a reduced temperature in the nozzle of the forge reduces fuel economy for ignition of the charge.

The closest to the claimed method is the ignition of the sintering mixture according to patent KI 2229665 [2].

The known method [2] includes heating the mixture, ignition and heating of the cake, carried out sequentially in the respective zones with heat from gas combustion, 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 arch beams of box-section, ending with a heat-receiving surface, facing the inside of the chamber.

Thus, the air supplied to the burners is heated with heat from the combustion products of gaseous fuel and heat from the radiation of burning solid fuel particles located in the upper part of the charge layer, i.e. due to the removal of heat 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 consumption is unlikely to decrease significantly, and in the case of transferring part of the heated air to additional chambers, fenced off from the main separating walls, the gas consumption may increase.

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

The present invention is the creation of energy-saving and more simple method of igniting the sintering mixture.

To solve this problem, the method of ignition of the sintering mixture moving on the sintering carts includes heating the mixture, the actual ignition and the heating of the cake, carried out sequentially in the corresponding zones with heat from gas combustion, while the 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, consisting of a set of completely 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 500x500 mm.

For the beneficial use of the arch heat, the air supplied to the gas burners is heated in an air duct installed above the arch of the ignition zone, the lower flat surface of the body of which corresponds to the outer surface of the arch of the ignition zone and is closest to it.

The charge is heated under the radial arch adjacent to the ignition arch with the volume of the working space increasing along the movement of the sintering carts.

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

In the inventive method, the air supplied to the burners is heated with heat from the outer surface of the roof of the ignition zone, consisting of a set of 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 arch and is closest to it.

As a result, heat is used to heat the air that has passed through the refractory roof of the most high-temperature zone, which is characterized by maximum heat loss, and could have been lost forever.

Thus, the heat required for ignition of the charge remains unchanged, and the supply of heated air to the burners allows to reduce the gas consumption in the ignition zone and provide heat to the other two, unheated areas: heating the charge and SPECA.

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In the first zone, the charge is heated under the radial refractory arch adjacent to the ignition arch, with a volume of working space increasing along the direction of movement of the sintering carts.

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

In the latter zone, it is also possible to produce heating of the cake under the refractory vault, which prevents the radiation of heat from the surface of the ignited mixture and the access to it of cold air.

Due to this, the heat treatment of the surface of the SPECA can be carried out with minimal expenditure of heat coming from the ignition zone.

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 for heating the charge.

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

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

Zone I corresponds to the heating zone of the charge, zone II to the zone of the actual ignition, zone III to the zone of heating of the sinter.

The heating of the charge layer moving on the sintering carriages is carried out in zone I under the roof of the refractory radial arch 1, which is at first 30-50 mm from the upper edge of the sintering carts.

Gas is burned in burners 2 zones II. The burners are mounted on the case of the air duct 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 solid arch of the ignition zone.

The air injected into the body of the duct takes heat from the bottom flat surface of its body and enters the burner.

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

The surface area of each unit with a burner facing inside the ignition zone is 500x500 mm. This size is a multiple of the grate area of sintering carts of various sizes and convenient for rational placement of burners and ensuring ignition uniformity. To optimize the volume of the working space of the ignition zone, the actual ignition of the charge is carried out under the roof, 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 probability of chemical destruction of the refractories of the vault increases due to the possible penetration of particles of iron and calcium oxides formed by the explosive destruction of fluxes, sludge, scale and some concentrates containing hydrated moisture and carbonates.

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

Heating of the cake is carried out in zone III under a refractory vault, which prevents the radiation of heat from the surface of the ignited mixture and the access to it of cold air, with minimal expenditure of heat coming from the ignition zone.

Thus, unlike the prototype method, the claimed method, by optimizing the use of gaseous fuel, is less energy-intensive and, at the same time, simpler.

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, while gas is 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 ignition zone is 500x500 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. - 2 008155 4. The method according to π. 1, characterized in that the charge is heated under the adjacent to the arch of the ignition zone radial arch with the volume of the working space increasing along the movement of the sintering trolleys.