WO2008100238A1

WO2008100238A1 - Device for producing iron or steel from iron oxide materials

Info

Publication number: WO2008100238A1
Application number: PCT/UA2007/000017
Authority: WO
Inventors: Anatoly Timofeevich Neklesa; Vadim Vladislavovich Novinskij
Original assignee: Anatoly Timofeevich Neklesa
Priority date: 2007-02-12
Filing date: 2007-03-19
Publication date: 2008-08-21
Also published as: UA83439C2; RU2007137946A; RU2361927C1

Abstract

The invention relates to metallurgy, in particular to devices for producing iron or steel by a direct reduction process and comprises a melting furnace (1) and a reduction reactor (2) which are combined by means of a lined jacket and separated by a masonry wall (3), in the top part of which a channel (4) for evacuating waste gas from the furnace (1) to the roof part (5) of the reactor (2) is situated. The furnace (1) is provided with indirect plasmotrons, two of which (7, 8) are located in the lid (9) of the furnace, and plasmotrons (11, 12) are located in the side wall thereof. The gas-evacuating channel (20) of the reactor (2) is connected, by means of a gas pipeline (22), to a batch preheater (6) which consists of two chambers (15) separated by a partition (16).

Description

A device for producing iron or steel from iron oxide materials The invention relates to the field of metallurgy, and in particular to installations for producing iron or steel by direct reduction.

A device for producing iron and / or its alloys from iron oxide materials is known, comprising a melting furnace equipped with means for supplying carbon-containing fuel and oxygen-containing gas directly into the liquid phase and into the space above it for afterburning the gas resulting from melting, an outlet with a discharge pipe exhaust gas, means for introducing iron oxide material into the afterburned exhaust gas for partial reduction of the material and gas cooling, installed and therein means for separating partially reduced material from gas and means for supplying partially reduced material to the smelter, according to the invention, the exhaust gas pipe is installed vertically and connected to means for loading iron oxide material in its lower part and to means for separation located in the upper part channel. The device provides means for accelerating the flow of exhaust gas, located in front of the device for introducing iron oxide material (Russian Patent N ° 2077595, CL 21B 13/14, application. 20.12.1989, publ. 20.04.1997).

However, the design of the device is complex, operations are carried out on a large number of channels, and further intensification of the material smelting process and reduction of capital and operating costs become difficult.

The closest in technical essence and the achieved result (prototype) is a device for the production of iron-carbon alloy, containing a reactor for preliminary reduction of iron oxide material and a reactor connected to it for producing iron-carbon alloy, including an input unit for pre-reduced material, nodes for the release of iron-carbon alloy and slag, means for injection of oxygen into the melt and removal of gaseous reaction products according to the invention, a reactor for producing elezouglerodistogo alloy made closed to restrict the intake of atmospheric gases therein and removing gaseous reaction products and is provided with additional means of blowing oxygen into the space above the molten bath, the device is equipped with a pre-reduced carbide-containing material heater connected to the reactor for producing an iron-carbon alloy by means for removing gaseous reaction products (Russian Patent M> 2060281, CL 21B 13/14, application 03.10.91, publ. Bulletin _Nal4, 1996).

In the proposed design of the device for the production of iron-carbon alloy, there are no devices for monitoring the temperature and composition of the reducing gas, the question of how to treat liquid and solid particles, for example, iron droplets in the exhaust gas stream without undesired sintering and deposits on the walls and the reactor lid, has not been resolved.

The basis of the invention is the task of improving the device for producing iron or steel from iron oxide materials by modifying the design of the melting furnace, reactor and heater, which will ensure both a high yield of the product and high energy efficiency with low capital costs.

The problem is solved in that in a device for producing iron or steel from iron oxide materials containing a melting furnace and a reduction reactor connected to it, a source material heater, input and output nodes of material and melting products, means for introducing oxygen-containing gas and removal of gaseous reaction products, according to the invention, the melting furnace and the recovery reactor are combined with a lined casing and separated by a masonry wall, in the upper part of which there is a horizontal channel for removal from the furnace of gaseous reaction products into the arched part of the recovery reactor, in the lower part of which there is a gas outlet channel connected by a gas line to the mixing chamber, which is connected through gas ducts to the internal cavity of the source material heater, made in the form of a sealed casing with an internal lining and vertical chambers placed in it , the side walls of which form an opening for the passage of gas with the upper cover of the heater, while gas is installed at the exit of the flues in the opening of the heater s torch and the bottom of each chamber, with one side located discharging node material, and the other - the flue gas channel, the gas manifold which is connected with an afterburner and flue gas venting. The melting furnace is equipped with indirect plasmatrons, two of which are located in the lid parallel to the longitudinal axis of the furnace, and in the lower part of the furnace plasmatrons are located on opposite walls symmetrically at an angle to the hearth, while nozzles for supplying oxygen or an oxygen-containing gas are located in the side walls of the furnace in the plane of the plasmatron installation. In the horizontal channel for the removal of gaseous reaction products from the furnace, pipes are connected to the pipelines for supplying steam, air and methane, and the mixing chamber is additionally equipped with pipelines for supplying air and methane, while in the channel for the removal of gaseous reaction products from the furnace and in the gas pipeline gas analyzers are installed in the mixing chamber, and the exhaust gas channels from each chamber of the source material heater are equipped with gates, and the vertical chambers of the source material heater are separated Lena between themselves by a partition.

The reducing atmosphere in the furnace was created with the help of plasma torches located in the lower part of the side walls of the furnace and oxygen-containing gas transported through nozzles, where the charge is preheated iron-containing pellets and coal loaded into the furnace through a wall-mounted input unit. Gases transported to the metal layer and formed during melting, lead to an intense rise of the molten metal and create an upward movement of spray, droplets and jets of molten metal and slag. To prevent the molten material and solid particles from sticking to the lid and walls of the furnace, two plasma torches are installed vertically in the furnace lid, during operation of which significant quantities of the transferred molten material and solid particles are removed, and additional mixing occurs in the metal and slag layer.

Hot carbon dioxide is formed at the outlet of the reduction reactor, the heat of which is used to preheat the source material in the preheater before it is fed to the reduction reactor.

To ensure simple control of the process, the device is equipped with gas analyzers installed in the channel for removing gaseous reaction products from the furnace and in the gas line in front of the mixing chamber, while pipelines for supplying steam, air and methane are additionally installed in the horizontal channel, and thermocouples in the arched part of the recovery reactor , and the mixing chamber is equipped with pipelines for supplying air and methane. In order to control the temperature of the gas in the source material heater, the exhaust gas channels of each chamber are equipped with gates, and burners are installed in the upper part of the heater at the outlet of the gas ducts. The invention is illustrated by drawings, where in FIG. 1 shows a general view of an apparatus for producing iron or steel from iron oxide materials; in FIG. 2 - source material heater, side view; in FIG. 3 - recovery reactor, side view. A device for producing iron or steel from iron oxide materials includes a melting furnace 1 and a reduction reactor 2, united by a lined casing and separated by a masonry wall 3, in the upper part of which a horizontal channel 4 is made for the removal of gaseous reaction products from the melting furnace 1 to the arched part 5 recovery reactor 2. The device is additionally equipped with a heater 6 of the source material containing a lined casing. The melting furnace 1 is equipped with indirect plasmatrons. The plasma torches 7 and 8 are located vertically in the cover 9 of the furnace, and the input unit 10 of the source material is shifted to the side wall of the furnace. In the lower part of the furnace, on opposite walls, plasmatrons 11 and 12 are mounted symmetrically at an angle to the hearth, and nozzles 13 and 14 for supplying oxygen or an oxygen-containing gas are located in the plane of installation of the plasmatrons. The heater 6 of the source material is made of vertical chambers 15, separated by, for example, a metal sheet 16. The side walls of the heater and the metal sheet 16 form an opening 18 with a top cover 17 for gas passage. In the lower part of the recovery reactor 2, under the grate 19, a gas outlet channel 20 is located, while the grate 19 is mounted with the possibility of tilt towards the outlet 21 of the metallization products. The gas outlet channel 20 of the recovery reactor 2 through the gas pipe 22, the mixing chamber 23 and the gas duct 24 is connected to the internal cavity of the heater 6, directly with the opening 18. The mixing chamber 23 is additionally provided with pipelines 25 and 26 for supplying air and methane. At the outlet of the gas duct 24, gas burners 27 are installed in the opening 18 of the heater 6. At the bottom of each chamber 15 of the heater 6 there is an unloading unit 28 and an exhaust gas channel 29, which is connected through the afterburner 30 to the flue gas outlet 31. The device is equipped with gas analyzers 32 installed in the horizontal channel 4 and in the gas pipe 22 in front of the mixing chamber 23. In the horizontal channel 4, there are also pipes 33, 34 and 35 connected by pipelines for supplying steam, air and methane. The channel 29 of each chamber of the heater 6 is equipped with a gate 36. Thermocouples 37 are placed in the arched part 5 of the recovery reactor. The device operates as follows. Before starting work, the melting furnace 1 and the reduction reactor 2 are heated to a temperature of 800-1000 C. When the set temperature is reached, the coal is first fed into the furnace through separate inlet chutes of the input unit 10, which is coated under the furnace, and then mixed material is loaded: carbon-containing material (coal ) and iron-containing material (pellets) with a ratio in the range of 0.2-0.4 s / or without additional accompanying substances. Since the input node 10 of the material is located near the wall of the furnace, the material in the shaft of the furnace is formed at an angle of repose, with an opening angle in the direction of the horizontal channel 4 for the removal of the gaseous reaction products from the smelting furnace. In parallel with the loading of the melting furnace 1, a predetermined volume of the starting material (pellets) is supplied to the reduction reactor 2 with the formation of a cavity in the arched part, limited by the level of the material. Start plasmatrons 11 and 12 in the melting furnace. After the plasmatrons have entered the operating mode, the upper plasmatrons 7 and 8 are turned on. A part of the carbon-containing material loaded onto the under furnace acts as a source of solid carbon for reduction. The remainder of the carbon-containing material acts as a protective layer that serves as a substrate for molten iron and prevents liquid iron / slag from entering the hearth refractory. In addition, a certain amount of carbon-containing material is oxidized by combustion products when oxygen-containing gas is supplied through nozzles 13 and 14 to form carbon monoxide, which is a reducing agent.

Gases during the melting reaction lead to an intense rise of solid carbon and slag from the metal layer, which creates an upward movement of sprays, drops and jets into the space above the molten bath. The operation of plasmatrons 7 and 8 creates a partial barrier to the transported molten material and solid particles, this helps to maintain the temperature inside the furnace, causes active mixing in the metal layer and the slag layer, and as a result, a moderately uniform temperature is established.

The device is designed taking into account the levels of the metal layer, the slag layer and taking into account bursts, drops and jets of molten metal and slag that are thrown into the upper space of the furnace. As the charge is lowered in the furnace, it is periodically recharged, and the metal and slag are partially released.

Gas leaves the smelting furnace through a horizontal channel 4 and enters the arched part 5 of the reduction reactor 2. The gas analyzer 32 determines the composition of the exhaust gas, and the temperature of the gas entering the arched part 5 of the reactor, determined by thermocouples 37. The operating temperature in the reduction reactor is limited by preventing the starting material from sticking together; the upper temperature limit is 800-850 ⁰ C. Therefore, a decrease in the temperature of the gas supplied to the reduction reactor by cooling is unavoidable. The correction of the composition and temperature of the gas is carried out by supplying to the channel 4 separate pipelines 33, 34, 35 of steam, air and methane. As a result of decomposition of CH ₄ - steam, an intensive decrease in the temperature of the gas leaving the smelting furnace occurs, and its reduction ability improves.

The chambers 15 of the heater are filled with source material through individual bins.

The gas leaving the recovery reactor through the gas outlet channel 20, located under the grate 19, is transported to the source material heater 6 through the mixing chamber 23, which is additionally supplied with air and methane to create a high-temperature coolant when the burners burn 27 gases entering through the duct 24 into the opening 18. The composition of the outgoing gas reduction reactor is controlled by a gas analyzer 32.

The level of the source material in the chamber 15 of the heater and the gas feed rate through the gas duct 24 is chosen so that under steady-state process conditions the gas penetrates the free space of the opening 18 and generates a temperature of about 750-800 ⁰ C. The temperature of the source material is controlled by the sliders 36 installed in the channel 29 of the exhaust gas of each chamber. The exhaust gas through the channels 29 of each chamber is sent to the flue gas outlet 31 through the afterburner 30. The heated source material is discharged through the discharge unit 28 located at the bottom of each chamber. The pressure at the gas supply and gas exhaust nodes of the device is set depending on the aerodynamic resistance of the charge layer.

This installation design makes it possible to transfer a significant amount of heat of the reducing gas generated in the melting furnace to the direct reduction process, and thus allows it to be used most efficiently.

This embodiment of the device allows before melting to intensively heat the charge in the heater by creating a high-temperature coolant during the combustion of gases from the recovery reactor. The design of the kiln eliminates the potentially serious problem of solid sediment and keeps the walls and lid of the kiln clean. The device provides increased productivity while reducing the height and volume of the furnace, its operational introduction into mode, ensuring compact production, high economic efficiency and high environmental safety.

Claims

Claim

1. A device for producing iron or steel from iron oxide materials, comprising a melting furnace (1) and a reduction reactor (2) connected to it, a heater (6) of the starting material, input units (10) and the discharge of material and smelting products, oxygen-containing input means gas and removal of gaseous reaction products, characterized in that the melting furnace (1) and recovery reactor (2) are combined with a lined casing and separated by a wall (3) of masonry, in the upper part of which a horizontal channel (4) is made for the removal of gaseous from the furnace reaction products into the arched part (5) of the reduction reactor (2), in the lower part of which there is a gas outlet channel (20) connected by a gas pipeline (22) to a mixing chamber (23), which is connected through gas ducts to the internal cavity of the preheater (6) of the starting material made in the form of a sealed casing with an inner lining and vertical chambers (15) placed in it, the side walls of which form an opening (18) with a top cover for the heater for gas passage, while at the outlet of the gas ducts in the opening (18) of the heater (6) installed gas burners (27), and in the lower part of each chamber, on one side there is a discharge unit (28) of material, and on the other, an exhaust gas channel (29), which is connected by a gas line to the afterburner (30) and the gas outlet (31) flue gas.

2. The device according to claim 1, characterized in that the melting furnace (1) is equipped with indirect plasmatrons, two of which (7.8) are located in the lid (9), parallel to the longitudinal axis of the furnace, and plasmatrons in the lower part of the furnace (11) , 12) are located on opposite walls symmetrically at an angle to the hearth, while nozzles (13.14) for supplying oxygen or an oxygen-containing gas are located in the side walls of the furnace in the plane of installation of the plasma torches (11D2).

3. The device according to p. 1, characterized in that in the horizontal channel (4) for the removal of gaseous reaction products from the furnace, nozzles (33.34.35) are connected to the pipelines for supplying steam, air and methane.

4. The device according to claim 1, characterized in that the mixing chamber (23) is additionally provided with pipelines (25.26) for supplying air and methane.

5. The device according to p. 3 and 4, characterized in that gas analyzers (32) are installed in the channel (4) for removing gaseous reaction products from the furnace and in the gas pipeline (22) in front of the mixing chamber (23).

6. The device according to p. 1, characterized in that the channels (29) of the exhaust gas with each chamber (15) of the heater (6) of the source material is equipped with gates (36).

7. The device according to p. 1, characterized in that the vertical chambers (15) of the heater (6) of the source material are separated by a partition (16).