RU1770706C - Roasting conveyer machine - Google Patents

Abstract

Usage: in the preparation of raw materials in the steel industry, namely the design of equipment for the production of agglomerated raw materials. SUBSTANCE: firing conveyor machine consists of a drying section 1 with a hood and blast chambers, a heating section 2 with a heating furnace 3 and vacuum chambers 4, a firing section 5 with a furnace 6 and vacuum chambers 7, equipped with side pockets 8 and a circumferential water collector 9, recovery sections 10 with a hood and vacuum chambers 7 with pockets 8 and a manifold 9, cooling sections 11 with a hood, blasting and vacuum chambers. The district manifold 9 is equipped with spray nozzles with saw nozzles, which together represent a system for saturating the recirculation gases with water vapor. Sealing pockets 8 are installed in the vacuum chambers of the firing sections 5 and recovery tO in their upper part at a height of 0.6--0.85 of the height of the vertical section of the vacuum chambers, and a system for saturating the recirculation gases with water vapor is installed under the sealing pockets 8 the length of the spray is 8-12 caliber nozzles, and the distance between the spray is 1.0-1.4 of their length. 2 ill.

Description

figure 1

The invention relates to the field of preparation of iron ore raw materials in ferrous metallurgy, and in particular to the design of equipment for the production of agglomerated raw materials.

Roasting conveyor machines are known which comprise a hearth and flue hoods of the drying, heating, roasting, recovery and cooling sections, blast chambers, vacuum chambers, and a steam recirculation gas saturation system 1.

For the prototype, we take a roasting conveyor machine containing a hearth and gas duct caps for the drying, heating, roasting, recovery and cooling sections, blast chambers, vacuum chambers with juice sealing pockets and a recirculation gas saturation system with water vapor 2.

The disadvantages of this design are:

a) the location of the recirculation gas saturation system with a water vapor-steam circuit is in the cooling section. In such a system, the coolant is almost entirely composed of water vapor, which requires a significant amount of its reproduction and, therefore, increased costs, At the same time, the use of other inert gases (nitrogen, carbon dioxide X in excess contained in the exhaust gases from the firing section is impossible. At the same time, fuel and energy costs for redistribution increase unnecessarily;

b) the absence of systems for producing low-oxidative flows of hot heat carrier containing 012% oxygen and enriched with water vapor, for use in the fuel-burning devices of the heating and calcining sections as combustion air and for diluting and introducing oxygen-free combustion products with a temperature of 1200-1350 ° C in the processed layer. As a result, reduced raw materials, i.e. the quality of the finished product does not meet the requirements of modern metallurgical processes;

c) the absence of systems for the simultaneous purification of gas from the oxidizing agent and the enrichment of this gas stream with water vapor while reducing the temperature potential of the coolant to the values required by the conditions of its transportation.

The aim of the invention is to improve product quality and

reduction of fuel and energy costs for redistribution.

The goal is achieved by the fact that in a firing conveyor machine containing a hearth, drying, heating, firing, recovery and cooling sections with flue hoods, blast chambers, vacuum chambers and side sealing pockets around them, connected through adjacent vacuum chambers with smoke pipe, a system for saturating the recirculation gases with water vapor, including spraying with spray nozzles. According to the invention, the sealing

pockets installed i in the vacuum chambers of the firing and recovery sections in their upper part at a height of 0.6-0.85 of the height of the vertical section of the vacuum chambers, and the recirculation gas saturation system

water vapor is installed under the sealing pockets, while the spray length is 8-12 gauge nozzles, and the distance between the spray nozzles is 1.0-1.4 of their length. The invention is illustrated in the drawings, wherein

in FIG. 1 prezileia schematic diagram of a firing conveyor machine (longitudinal section); Fig. 2 is a transverse section through the machine in the firing zone.

The roasting machine consists of a section

drying 1 with a cap and blowing chambers, heating sections 2 with a heating furnace 3 and vacuum chambers 4, firing sections 5 with goon 6 and vacuum chambers 7, equipped with side pockets 8 and

a district water collector 9, a recovery section 10 with a cap and vacuum 7 chambers with pockets 8 and collectors 9, a cooling section 11 with a cap, blow and vacuum chambers. The circumferential manifold 9 is equipped with spray nozzles 12 with spray nozzles 13, which together represent a system for saturating the recirculation gases with water vapor. Sealing pockets should be located in the upper part of the vacuum chambers, starting og their upper edge at a height of 0.6-0.85 of the height of the vertical section of the vacuum chamber. With a lower height of the sealing pockets (less than 0.6 height

0 the vertical section of the vacuum chamber does not provide the required tightness, due to suction, the concentration of water vapor in the coolant decreases, its composition deteriorates and the quality of the finished product decreases

5 products. With a greater height of the sealing pockets (more than 0.85 of the height of the vertical section of the vacuum chamber), due to the absence of the required conditions for the evaporation of finely sprayed water, it becomes

additional cooling required

heat carrier by air, loss of its temperature potential and increase in heat consumption in the process.

The spray length should be 8-12 caliber nozzles. With a shorter spray length (less than 8 gauge nozzles), a continuous turbulized jet is not formed, the droplet size of the sawn water remains high and, as a result, the quality of the finished product worsens, and the cost of redistribution increases.

With a longer spray length (more than 12 nozzle calibres), the jet structure has already been formed, while an unjustified increase in the length of the nozzle leads to an increase in the gas-dynamic resistance of the system and an increase in energy consumption for the process.

The distance sprayed from each other horizontally should be equal to 1.0 to 1.4 of their length. At a smaller distance sprayed from each other (less than 1.0 spray length), the jets intersect, coagulates the moisture particles, reduces the efficiency of its evaporation and, as a result, the quality of the finished product deteriorates and the fuel and energy costs of the process increase.

With a greater distance between the sprayers (over 1.4 spray lengths), the uneven supply of finely dispersed moisture into the hot gas stream increases, the efficiency of its enrichment with water vapor decreases, and the quality of the finished product deteriorates.

The roasting machine operates as follows.

Raw pellets are loaded onto a conveyor belt and subsequently dried, heated, calcined, recovered and cooled. In the drying section 1, a coolant with a temperature of, for example 350 ° C, is transported from the cooling zone, blown into the layer through the blast chambers, external moisture is removed from the pellets and discharged through the hood of the zone into the chimney. In furnaces 3 and 6 of sections 2 and 5, respectively, in a fuel-burning device, a fuel-air mixture with a reduced oxygen content is burned. The air-fuel mixture is formed from flows of fuel, primary and secondary air,

The primary air flow, atmospheric, is served in the traditional way. The secondary stream supplied from the vacuum chambers 7 is composed of neutral or, if necessary, slightly oxidizing gases. Oxygen-free products of combustion from the hearth 3 with a temperature of 1050-1200 ° C are fed into the bed, subjected to final drying, heating and discharged through the vacuum chambers 4 into the chimney. From hearth 6, oxygen-free combustion products with a temperature of 1250-1350 ° C are fed to the section bed

firing 5, it is subjected to strengthening firing and with a temperature of 450-700 ° C is discharged through chambers 7. Suction-purges falling into chamber 7 are collected in side pockets 8 and along the connecting path

4 heating zones are discharged into the vacuum chambers and from there into the chimney. Fine sprayed water is fed into the stream of hot gases leaving the bed. It is fed through a manifold 9, sprayed 12, and discharged through a nozzle 13 in a gas stream. As a result, water evaporates. enrichment of the coolant with water vapor and a decrease in the temperature of the coolant to 350 ° С.

The resulting coolant is used, if necessary, in fuel burning devices in the recovery and cooling sections.

The heat carrier is supplied to the recovery section 10 through a cap, heat is transferred from top to bottom in the layer, and the exhaust gases are also removed through the vacuum chambers 7 of the recovery zone, similar to the above construction and

working in the same way. The pellets are then cooled in section 11 and sent to a warehouse.

Claims (1)

The application of the present invention provides an increase in productivity by 2-4%, a decrease in fuel and electricity consumption by 7-8 and 1.5-2.0%, respectively, and an improvement in the quality of fired pellets. With this improvement in process performance, the cost of fired pellets is reduced by 0.09 rub / t of finished product. SUMMARY OF THE INVENTION A firing conveyor machine comprising a furnace, drying, heating, calcining, recovery and cooling sections with flue hoods, blast chambers, vacuum chambers and side sealing pockets around them, connected through adjacent vacuum chambers to a flue pipe, a system for saturating the recirculation gases with water vapor, including spraying with spray nozzles, which requires that, in order to improve product quality and reduce fuel and energy costs, sealing pockets are installed in the vacuum chambers of the firing and recovery section in their upper part at a height of 0.6-0.85 of the height of the vertical section of the vacuum chambers, and the recirculation gas saturation system a water puff is installed under the seal equal to 0-12 calibers of the nozzle, and the distance is pocket., mm, while the length of the spray between the sprayers is 1.0-1.4 of their length. 9Fig. 2