RU87166U1 - TECHNOLOGICAL LINE FOR PRODUCTION OF METALLIZED PRODUCT - Google Patents

Abstract

1. A technological line for the production of a metallized product, including a coal crushing section, a preparation section for iron-carbon-containing agglomerates, equipped with a mixer of raw iron-carbon-containing components, a sinter plant, a drying plant, a preparation and supply section for a heat carrier, a metallization furnace with a rotating hearth, equipped with loading devices and unloading, with nozzles for supplying fuel, connected by transportation lines to the site for the preparation of iron-carbon-containing sinter c, in the preparation and supply section of the coolant and through the exhaust gas removal device with a gas treatment unit, wherein a heat recuperator in the form of an air heat exchanger connected by a hot air supply line to the drying unit is installed in the exhaust gas line in front of the gas treatment unit, characterized in that the preparation section and the fuel supply is equipped with at least two coal gasifiers, each of which is connected by transportation lines to the coal crushing section and the gas supply line th fuel injectors plating furnace, which is also connected to the heat exchanger hot air supply line. ! 2. The production line according to claim 1, characterized in that the area of coal crushing is equipped with at least two crushers. ! 3. The production line according to claim 1, characterized in that the drying unit is equipped with a gas exhaust device connected to a gas treatment unit. ! 4. The production line according to claim 1, characterized in that the site for the preparation of iron-carbon-containing pellets is equipped with a roller screen.

Description

The proposed solution relates to the technology of metal reduction by heating a layer of a material containing metal oxide and a carbon reducing agent and can be used in the manufacture of a metallized product, such as iron, in a moving hearth furnace.

In the technology of direct reduction of metal from an iron-carbon-containing material containing metal oxide and a reducing agent, the choice of a carbon reducing agent and a type of fuel for heating the processed iron-carbon-containing material is important. The reducing agent must ensure effective interaction with the metal oxide during the entire processing time and throughout the volume of the material loaded onto the under furnace. At the same time, carbon material should be scarce and inexpensive. The fuel reagent supplied through the nozzles to the furnace must ensure effective interaction of the reaction components and the necessary conditions for obtaining a high-quality product.

The use of less expensive types of raw materials and energy carriers, the use of technologies for preparing raw materials for use in the process that do not require significant energy costs and special expensive equipment, and the most efficient use of the energy component of the process are preferable.

The well-known "Method for producing molten iron" (RF patent No. 2293121, СВВ 13/14, 2007), the first stage of which implements the technology of direct metal reduction by heating a layer of a material containing metal oxide and a carbon reducing agent in a moving hearth furnace. The method in the first stage involves introducing a mixture of starting materials containing iron oxide-based material and a carbon-containing reducing agent into a heating reduction furnace in order to reduce iron oxide in the starting material mixture using a carbon-containing reducing agent to solid reduced iron.

The process is implemented on the production line described in the description (FIG. 1), which includes an iron-containing material preparation section equipped with a dryer, a mill and material transportation lines, a carbon-containing material preparation section equipped with a crusher and material transportation lines, an iron-carbon-containing agglomerate preparation section equipped with a mixer raw iron-carbon components, binder and auxiliary materials, sinter plant, drying plant and lin s transport linking it with portions of preparation of raw materials and with a rotary hearth furnace provided with a loading and unloading devices, nozzles for supplying fuel, the fuel supply line connected with the portion preparing and feeding the coolant through the device and for discharging exhaust gas from the gas purification installation. A boiler for extracting heat from the exhaust gases and a heat recuperator in the form of an air heat exchanger connected by a hot air supply line to the drying unit are installed in the furnace exhaust gas exhaust line in front of the gas treatment plant.

To carry out the process, dust-free exhaust hot gas from a smelting furnace is fed into the rotary kiln from the second stage of this technology — production of molten iron and fuel in the form of natural gas or powdered coal.

According to the technical essence, the presence of similar features, the technological scheme designed to implement the first stage of technology according to the patent of the Russian Federation No. 2293121 is selected as the closest analogue.

The main disadvantages of the known solutions are as follows.

The supply of exhaust hot gas from the melting furnace to the rotary kiln from the second stage of the process requires additional costs for dedusting the gas, and given that the gas being purified has a high temperature, such purification is very costly and ineffective, both technologically and in terms of the service life of the treatment equipment. If the degree of dust removal is not high enough, it can accumulate in a rotary kiln, which will lead to violations of the stable continuous operation of the equipment.

The supply of fuel in the form of natural gas or powdered coal to a rotary kiln increases the cost of implementing the technology, both in terms of the cost of reagents and equipment.

The objective of the proposed technical solution is to increase the technical and economic indicators of the process of metal reduction from iron-carbon-containing material containing metal oxide and an oxide reducing agent in a moving hearth furnace.

Technical results are the reduction of energy and material costs for the preparation of the material and the recovery process.

Technical results are achieved by the fact that in the technological line for the production of a metallized product, including a coal crushing section, a preparation section for iron-carbon-containing agglomerates, equipped with a mixer of raw iron-carbon-containing components, a sinter plant, a drying unit, a fuel preparation and supply section, a metallization furnace with a rotating a hearth equipped with loading and unloading devices, nozzles for supplying fuel, connected by transportation lines to the preparation section and iron-carbon-containing agglomerates, in the preparation and supply of the coolant and through the exhaust gas removal device with a gas treatment unit, moreover, a heat recuperator in the form of an air heat exchanger connected to the hot air supply line to the drying unit is installed in the exhaust gas line in front of the gas treatment unit, the fuel preparation and supply section is equipped with at least two coal gasifiers, each of which is connected by transportation lines to the coal crushing section and a line supply of gaseous fuel with nozzles of a metallization furnace, to which a heat recuperator is also connected by a hot air supply line.

In addition, the coal crushing section can be equipped with at least two crushers, the drying unit can be equipped with a gas exhaust device connected to the gas treatment unit, and the preparation section for iron-carbon-containing pellets can be equipped with a roller screen.

A comparative analysis of the proposed technical solution with the solution selected as the closest analogue shows the following.

The proposed solution and the solution for the closest analogue are characterized by similar features.

Technological lines according to the well-known solution and proposed include:

- a coal crushing section equipped with crushing equipment;

- site preparation of iron-carbon agglomerates, equipped with:

- a mixer of raw materials;

- sinter plant;

- dryer;

- fuel preparation and supply section;

- a metallization furnace with a rotating hearth, equipped with:

- loading device;

- unloading device;

- nozzles for supplying fuel;

- a device for exhaust gas;

- gas treatment plant;

- a heat recuperator, in the form of an air heat exchanger, installed in the exhaust gas line in front of the gas treatment plant;

- a heat recuperator, in the form of an air heat exchanger, is connected by a hot air supply line to the drying unit.

The proposed production line is also characterized by features that are different from the features that characterize the solution for the closest analogue:

- the fuel preparation and supply section is equipped with at least two coal gasifiers;

- each gasifier is connected by transportation lines to a coal crushing section and a gaseous fuel supply line with nozzles of a metallization furnace;

- a heat recuperator, in the form of an air heat exchanger, is connected by hot air supply lines to the nozzles of a metallization furnace.

In addition, the coal crushing section can be equipped with at least two crushers, the drying unit can be equipped with a gas exhaust device connected to the gas treatment unit, and the preparation section for iron-carbon-containing pellets can be equipped with a roller screen.

The presence in the proposed solution of signs other than those characterizing the solution according to the closest analogue allows us to conclude that the proposed solution meets the condition of patentability of the invention of “novelty”.

The technical essence of the proposed solution is as follows.

In the proposed metallized product production line, the fuel preparation and supply section is equipped with at least two coal gasifiers, since the material is heated by supplying gaseous fuel obtained in the coal gasifier to the furnace. In this case, it is used to ensure the recovery process, not gas, not liquid fuel or coal powder, but carbon gas obtained by burning crushed coal in a coal gasifier. Moreover, the preparation of a gas mixture of the necessary composition for the technological process - “mixed” gas is carried out in the gasifier by supplying crushed coal and water to it in certain proportions. Thus obtained "mixed" gas through nozzles enters the furnace. Preferably, crushed coal fractions of 13-50 mm are fed into the gasifier. The use of coal is advisable, both economically - whiter cheaper carbon-containing material that does not require special technological preparation for use, and in the technological aspect.

The use of crushed hard coal as a source for the preparation of a coolant greatly simplifies the process flow diagram, since crushed hard coal of various fractions is used for the preparation of a coolant and as a carbon reducing agent in the proposed technological scheme. Thus, almost complete processing of incoming coal raw materials is carried out by crushing it and sending different fractions to various stages of the processing line. To ensure the smooth operation of the rotary kiln and stabilization of the process parameters, the production line is equipped with at least two coal gasifiers. For guaranteed provision of crushed coal in two stages, the coal crushing section can be equipped with at least two crushers.

To achieve high technical and economic indicators of the process of metal recovery from oxide, the carbonaceous material must be non-deficient and inexpensive. In the proposed solution, crushed coal fractions of not more than 3 mm, which is obtained by crushing the feedstock, are used as a carbon reducing agent.

Coal is a natural concentrated (densified) carbonaceous material from which a gradual consumption of carbon occurs during the reduction reaction. At the same time, crushing and screening equipment and low energy costs are required to prepare the necessary carbon reducing agent.

The effectiveness of the proposed technology is also enhanced by returning heat energy to the process, since both the gases for heat treatment of the agglomerates in the drying chamber and the heated gas supplied to the furnace nozzles together with “mixed gas from gasifiers” are supplied from the exhaust gas cooling exchanger of the metallization furnace. This return of part of the thermal energy allows to reduce the cost of preparing materials for use, to reduce the consumption of “mixed” gas, to cool the gas stream going to the chimney, to increase the service life of gas cleaning equipment.

The proposed production line for the production of a metallized product includes (Figure 1) a coal crushing section equipped with two crushers 1 and connected by transportation lines 2, 3 with a coal storage (not shown) and with a mixer 4, a transportation line 5 connecting the iron ore concentrate storage ( not shown) with a mixer 4, an agglomeration unit 6 connected by a conveyance line 7 with a mixer 4 and a conveyor line 8 with a roller screen 9, which is connected by a conveyor line of agglomerates 10 to a drying unit th 11. The drying unit 11 is connected by a conveyance line 12 to a loading device 13 of a metallization furnace 14 with a rotary hearth, equipped with nozzles 15 for supplying fuel, through which gaseous fuel is supplied to the furnace 14 through transport lines 16 from coal gasifiers 17. The coal gasifiers 17 are connected by transport lines 18 to the crushers 1. The furnace 14 is also equipped with a discharge device 19 and an exhaust gas device 20 connected by an exhaust gas exhaust line 21 to a gas treatment unit 22. In the exhaust gas exhaust line 21, a recuperator is installed in front of the gas treatment installation 22. heat 23, in the form of an air heat exchanger, connected by a hot air supply line 24 to a dryer 11, hot air supply lines 25 to nozzles 15. The dryer 11 is also connected iniey exhaust 26 from the gas purification installation 27.

The technological line works as follows.

Coal from the warehouse along the transportation lines 2, made in the form of belt conveyors, enters the crusher 1 and is crushed, followed by separation into vibrating screens into fractions: less than 3 mm, 3-1 3 mm, 13-50 mm. A fraction of less than 3 mm through transport line 3 enters mixer 4, a fraction of 13-50 mm through transport lines 18 enters coal gasifiers 17, fractions from 3 to 13 mm are crushed additionally to a fraction of less than 3 mm and then sent through line 3 to mixer 4 .

Iron ore concentrate from the warehouse through the transport line 5 enters the mixer 4. The feedstock is mixed in the mixer in metered quantities, if necessary, a binder, other components are added, the mixture is moistened. From the mixer 4, the resulting mass is transported through a conveyor line 7 to an agglomeration unit 6, where agglomerates are formed and through an conveyor line 8, the agglomerates are transferred to a roller screen 9, where substandard agglomerated material is separated and then returned to the agglomeration unit 6. Further, the agglomerates are passed through a line transportation 10 is supplied to the drying unit 11. The heat treatment of the agglomerates in the drying unit 11 is carried out by hot air supplied through the hot feed line first air 24 from the heat recuperator 23, made in the form of an air heat exchanger. The exhaust air from the drying installation 11 is fed through the exhaust gas 26 exhaust gas line to the gas treatment unit 27. The heat-treated agglomerates are transported via the transportation line 12 to the loading device 13 of the metallization furnace 14 from which the material is continuously loaded onto a rotating bed. Gaseous fuel received in coal gasifiers 17 enters the furnace 14 through the nozzles 15 along the transport lines 16. Hot air is also supplied to the nozzles 15 through the supply lines 25. When agglomerates are heated, iron is reduced. Then, the processed material is cooled and discharged from the hearth of the furnace 14 using an unloading device 19. The exhaust gas from the furnace 14 is discharged through an exhaust gas exhaust device 20 connected to the exhaust gas exhaust line 21 through a heat recuperator 23 with a gas treatment unit 22.

Using the proposed production line for producing a metallized product in a rotary hearth furnace allows expanding the technological capabilities of the process, expanding the use of non-traditional types of raw materials and fuels, and increasing the technical and economic parameters of the technology for direct reduction of metal from iron-carbon-containing material.

Claims (4)

1. A technological line for the production of a metallized product, including a coal crushing section, a preparation section for iron-carbon-containing agglomerates, equipped with a mixer of raw iron-carbon-containing components, a sinter plant, a drying plant, a preparation and supply section for a heat carrier, a metallization furnace with a rotating hearth, equipped with loading devices and unloading, with nozzles for supplying fuel, connected by transportation lines to the site for the preparation of iron-carbon-containing sinter c, in the preparation and supply section of the coolant and through the exhaust gas removal device with a gas treatment unit, wherein a heat recuperator in the form of an air heat exchanger connected by a hot air supply line to the drying unit is installed in the exhaust gas line in front of the gas treatment unit, characterized in that the preparation section and the fuel supply is equipped with at least two coal gasifiers, each of which is connected by transportation lines to the coal crushing section and the gas supply line th fuel injectors plating furnace, which is also connected to the heat exchanger hot air supply line. 2. The production line according to claim 1, characterized in that the area of coal crushing is equipped with at least two crushers. 3. The production line according to claim 1, characterized in that the drying unit is equipped with a gas exhaust device connected to a gas treatment unit. 4. The production line according to claim 1, characterized in that the site for the preparation of iron-carbon-containing pellets is equipped with a roller screen.