RU93802U1 - TECHNOLOGICAL LINE FOR THE 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 to the hot air supply line with a drying unit is installed in the exhaust gas line in front of the gas treatment unit, characterized in that the preparation section iron-carbon-containing agglomerates is equipped with a line for returning substandard agglomerate to the sinter plant, utilities are installed in the exhaust gas line Discount boiler and discharging device is provided with a magnetic separator. ! 2. The production line according to claim 1, characterized in that the fuel preparation and supply section is equipped with at least two coal gasifiers, each of which is connected by transport lines to the coal crushing section and the gaseous fuel supply line with nozzles of the metallization furnace, to which it is also connected heat recuperator with a hot air supply line. ! 3. The production line according to claim 1, characterized in that the area of coal crushing is equipped with at least

Description

The 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, for example iron, in a moving hearth furnace.

In the technology of direct metal reduction, the rational use of material and energy resources in the implementation of the process is important. The material loaded onto the rotating under the furnace must ensure effective interaction of the carbon reducing agent with the metal oxide during the entire processing time and throughout the volume of the material loaded on the under the furnace. The feed material in the form of pellets must have a certain particle size distribution to obtain a layer of material that provides these conditions. Carbon material should be non-deficient and inexpensive, the fuel reagent supplied through nozzles to the furnace should ensure effective interaction of the reaction components and the necessary conditions for obtaining a high-quality product.

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

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 in the description in the description of the production line (Figure 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 agglomerate preparation section equipped with mixer of raw iron-carbon-containing components, binder and auxiliary materials, sinter plant, drying plant and lin transportation links connecting it to the areas for preparing raw materials and to a rotary hearth furnace equipped with loading and unloading devices, nozzles for supplying fuel, connected by a fuel supply line to the preparation and supply section of the coolant, and through an exhaust gas removal device with a gas treatment plant. 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.

All agglomerated and dried material is fed into the rotary kiln, which increases the loss of material and reduces the efficiency of the recovery process.

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 gas, and given that the gas being cleaned 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 gas purification from dust 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 a 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 production 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, an agglomeration unit, a drying unit, a preparation and supply section of a heat carrier, a metallization furnace with a rotating a hearth equipped with loading and unloading devices, nozzles for supplying fuel, connected by transportation lines to a section under preparation of iron-carbon-containing agglomerates, a heat-treatment preparation and supply section and, through an exhaust gas exhaust 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 with a drying unit is installed in the exhaust gas line in front of the gas treatment unit, the preparation section for iron-carbon-containing agglomerates is equipped with a return line for substandard agglomerate to the sinter plant, in the waste disposal line scratch scrappage boiler installed and unloading device is provided with a magnetic separator.

In addition, in the proposed production line, the fuel preparation and supply section can be equipped with at least two coal gasifiers, each of which is connected by transport lines to the coal crushing section and the gaseous fuel supply line with nozzles of the metallization furnace, to which a heat recuperator is also connected a hot air supply line, the coal crushing section can be equipped with at least two crushers, and the drying unit can be equipped with a gas exhaust device connected to the gas treatment unit oh installation.

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 site for the preparation of iron-carbon-containing agglomerates is equipped with a return line for substandard agglomerate to the sinter plant;

- In the exhaust gas exhaust line a recycling boiler is installed;

- the discharge device is equipped with a magnetic separator.

In addition, in the proposed production line, the fuel preparation and supply section can be equipped with at least two coal gasifiers, each of which is connected by transport lines to the coal crushing section and the gaseous fuel supply line with nozzles of the metallization furnace, to which a heat recuperator is also connected a hot air supply line, the coal crushing section can be equipped with at least two crushers, and the drying unit can be equipped with a gas exhaust device connected to the gas treatment unit oh installation.

The presence in the proposed solution of signs that are different from those that characterize the solution according to the closest analogue allows us to conclude that the proposed solution meets the condition of patentability of the utility model of "novelty."

The technical essence of the proposed solution is as follows. In the proposed line for the production of metallized product, the preparation section for iron-carbon-containing agglomerates is equipped with a line for returning substandard agglomerate to the sinter plant. The return of substandard material back to the sintering stage provides a certain granulometric composition of the charged charge to obtain a layer of material that ensures the effective interaction of the carbon reducing agent with metal oxide during the entire processing time and throughout the volume of the material loaded on under the furnace. In addition, the return of substandard materials reduces the unproductive energy costs of heat treatment of agglomerates, reduces material losses in the process due to losses during transportation and loading, as well as dust removal during heat treatment. Installation of a recycling boiler in the exhaust gas exhaust line will allow returning part of the waste to the gas treatment system as heat energy for production purposes, lowering the temperature of the exhaust gases and increasing the life of the gas cleaning equipment. The number of waste heat boilers installed in the boiler room depends on the productivity of the furnace, the number of furnaces connected to a centralized gas treatment system. The presence of a magnetic separator in the furnace unloading device allows you to effectively separate the marketable product and slag, to increase the consumer quality of the product.

In the proposed production line for the production of a metallized product, the fuel preparation and supply section can be equipped with at least two coal gasifiers, since the material can be 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 technological scheme of the process, 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 increased 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 the “mixed” gas from the gasifiers are supplied from the exhaust gas cooling heat 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, (Fig. 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 storage concentrate (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 substandard agglomerated material 10 back to the agglomeration and the transportation line of the agglomerates 11 with the drying unit 12. The drying unit 12 is connected by a transportation line 13 to the loading device 14 of the metallization furnace 15 with a rotary hearth, equipped with nozzles 16 for supplying fuel, through which to the furnace 15 through transportation lines 17 of coal gasifiers 18 gaseous fuel is supplied. Coal gasifiers 18 are connected by transportation lines 19 to crushers 1. The furnace 15 is also equipped with a discharge device 20, a magnetic separator 21 and an exhaust gas device 22 connected by an exhaust gas line 23 to a gas treatment unit 26. In the exhaust gas line 23, before the gas treatment installation 26 installed a recycling boiler 24 and installed a heat recuperator 25, in the form of an air heat exchanger, connected by a hot air supply line 27 to a drying unit 12 and hot supply lines 28 with its air nozzles 16. The dryer 12 is also connected to the exhaust line 29 with the gas purification system 30.

The technology is implemented 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, 3-13 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 19 enters coal gasifiers 18, fractions of 3 to 13 mm are further crushed to a fraction of less than 3 mm and then sent via 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 4 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 fed to a roller screen 9, where substandard agglomerated material is separated (less than 9.5 mm), which is transported via a conveyor line 10 returns to agglomeration. From the screen 9, the agglomerates are transported through the conveyor line 11 to the drying unit 12. The heat treatment of the agglomerates in the drying unit 12 is carried out by the hot air supplied through the hot air supply line 27 from the heat recuperator 25, made in the form of an air heat exchanger. The exhaust air from the drying unit 12 is fed through the exhaust gas line 29 to the gas treatment unit 30. The heat-treated agglomerates are transported via a conveying line 13 to the charging device 14 of the metallization furnace 15, from which the material is continuously loaded onto a rotating bed. Gaseous fuel received in coal gasifiers 18 enters the furnace 15 through the nozzles 16 along the transport lines 17. Hot air is also supplied to the nozzles 16 through the supply lines 28. When agglomerates are heated, iron is reduced. Then the processed material is cooled and discharged from the hearth of the furnace 15 using a discharge device 19 as a mixture of iron and slag granules and passes through a magnetic separator 21, where metal is separated from the slag. The exhaust gas from the furnace 15 is discharged through the exhaust gas exhaust device 22 connected to the exhaust gas exhaust line 23 through a waste heat boiler 24 and a heat recovery unit 25 with a gas treatment unit 26.

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, returning some of the heat of the exhaust gases to production, 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, an agglomeration 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 to the hot air supply line with a drying unit is installed in the exhaust gas line in front of the gas treatment unit, characterized in that the preparation section iron-carbon-containing agglomerates is equipped with a line for returning substandard agglomerate to the sinter plant, utilities are installed in the exhaust gas line Discount boiler and discharging device is provided with a magnetic separator. 2. The production line according to claim 1, characterized in that the fuel preparation and supply section is equipped with at least two coal gasifiers, each of which is connected by transport lines to the coal crushing section and the gaseous fuel supply line with nozzles of the metallization furnace, to which it is also connected heat recuperator with a hot air supply line. 3. The production line according to claim 1, characterized in that the area of coal crushing is equipped with at least two crushers. 4. 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.