KR850001633B1 - Apparatus for manufacturing sponge iron - Google Patents

Abstract

A method and apparatus for manufacturing sponge iron by the continuous reduction of iron oxides in a shaft utilizing recirculation gases is discussed. Reaction gas is removed from the shaft furnace; substantially cleaned of all CO2 and H2O; and then divided into at least two flow portions, one of which is passed into a gas generator shaft. This shaft is filled with a solid reducing agent and has a plasma burner arranged in the lower portion of the shaft. An oxidant is injected into the hot gas from the plasma burner, so as to form a gas mixture comprised primarily of CO and H2.

Description

Sponge Iron Manufacturing Equipment

Process schematic diagram illustrating the practice of the present invention.

The present invention relates to an apparatus for producing spongy iron, and in particular, the present invention relates to an apparatus for producing reduced gas for producing spongy iron by continuously reducing iron oxide in a regenerator using a recycle gas.

Conventionally, a conventional apparatus for producing sponge iron using a solid reducing agent such as coke as a reducing agent uses a shaft combined with a coal gasifier based on partial combustion. High facility costs and exceptionally high energy consumption.

Disadvantages and problems with the apparatus can be almost solved and supplemented by the apparatus according to the present invention. That is, the apparatus according to the present invention comprises: an axis for reacting iron oxide with a reducing gas consisting mainly of CO and H ₂ ; A mechanism connected to the top of the shaft for removing reactant gas from the shaft; Scrubbing mechanism for removing CO ₂ from the reaction gas above; A mechanism for separating the washed reaction gas into at least two flow portions; A gas generating shaft almost filled with a solid reducing agent, a plasma burner mounted below the gas generating shaft, and a mechanism for introducing an oxidant into the heated gas by the plasma burner to produce an intermediate gas mixture consisting mainly of CO and H ₂ . A gas generator which receives at least one of the two flow parts above; A mixing mechanism for controlling mixing the intermediate gas mixture with the reaction gas of at least one of the two flow parts to obtain a reducing gas; And a mechanism for introducing a reducing gas into the lower portion of the shaft, wherein the reducing gas is manufactured for producing iron sponge by continuous reduction of iron oxide.

In the apparatus, the reducing gas consists mainly of CO and H ₂ and is sent countercurrent to iron oxide and is produced with the aid of a plasma generator from a recycle gas, such as extra gas produced from a solid reducing agent, in addition to the reaction gas from the shaft. The recycle gas is first washed almost from CO ₂ and H ₂ O, and then the cleaned gas is divided into two parts, one of which is sent to the plasma generator. The plasma generator is composed of a gas generating shaft which is almost filled with a solid reducing agent such as coke or the like. The plasma burner is mounted on the lower part of the gas generating shaft, and water and / or oxygen gas are injected into the hot gas stream from the plasma burner to cause a reaction with a reducing agent, thereby forming a mixture mainly consisting of CO and H ₂ . The temperature of the gas produced is kept within a range in which the ash contained in the solid reducing agent can form slag. The hot CO-H ₂ mixture coming from the gas generator is mixed with at least another stream of scrubbed recycle gas at a rate such that the temperature of the final gas mixture may be suitable for the reduction process.

One feature of the process of the device of the present invention is to control the temperature of the gas produced in the gas generator in the range of 1300 to 1500 ° C. It is also preferred to mix the final gas mixture with the second stream before feeding it to the bottom of the furnace so that its temperature is within the range of 700 to 1000 ° C.

Another feature of the process of the device of the present invention is that the recycle gas is washed in a gas cleaner until the CO ₂ content is preferably 2% or less.

Referring to the flow of the process by the apparatus of the present invention through the following drawings as follows.

The reduction of the iron oxide mass is carried out in the shaft 1. The iron oxide mass is fed into the shaft 1 through a sluice valve 3 and is treated by the countercurrent flow of hot reducing gas consisting mainly of carbon monoxide and hydrogen gas supplied from the lower portion 4 of the shaft 1. . Sponge iron products are discharged through the outlet 5 in the lower part 4 of the shaft 1, and the reducing gas reacted with 30 to 50% is discharged through the outlet 6 in the upper part of the shaft 1. do.

In this way, the gas discharged from the reactor 1 contained not only 50 to 70% of unreacted CO and H ₂ but also reaction products CO ₂ and H ₂ O. These gases can still be reused because of their relatively high CO and H ₂ content, but the content of CO ₂ and H ₂ O must be reduced to 5% or less in order to reuse them as reducing gases.

This can be achieved by sending gas to scrubber 7 (CO ₂ / H ₂ O cleaning). Reaction products CO ₂ and H ₂ O are removed when the gas passes through this scrubber and the amount of gas is balanced in the actual scrubbing to avoid ignition of the gas. In addition, the scrubber 7 may contain monoethanolamine as the active substance, and the CO ₂ content in the gas may be appropriately reduced to 2% or less when passing through the scrubber.

After the gas has passed through the scrubber 7, it enters the compressor 8 and the pressure is increased to the extent necessary for the performance of the process and divided into at least two flow sections 9, 10.

The flow 9 is at room temperature and enters the gas generator 11 where extra gas is generated from a solid reducing agent, preferably coke and water or oxygen gas. The gas flow 9 is used as the plasma gas in the gas generator 11, and the amount of energy required in the gas generating process is supplied by the plasma burner 12.

The gas generator 11 is almost filled with a solid reducing agent, preferably coke. The oxidant, preferably water and / or oxygen gas, is supplied to the gas generator 11 via the jet 13 and then permeated into the hot gas stream exiting the plasma burner 12. In addition, the reducing agent may be added in the form of powder through the injector 13a from the outside.

The supplemental reducing agent is preferably coal powder having a particle size of 20 mesh or less, preferably 100 mesh or less. Therefore, the hot gas flow from the plasma burner acts on the reduction to form CO and H ₂ .

When supplying energy into the gas generator 11, the amount of ash so that the ash present in the coal dust melts the slag 14, which can be removed through the discharge mechanism 16 in liquid or solid form at the bottom of the gas generator 11. Adjust On the other hand, since the presence of ash, the temperature range is preferably selected to 1300 to 1500 ℃.

The reducing gas generated in the apparatus may contain sulfur contained in coal except that it contains CO and H ₂ . This intermediate gas mixture is therefore passed through a sulfur filter 15 (eg dolomite filter) which reduces the sulfur content to a level suitable for the production of sponge iron, preferably below 75 ppm.

In addition, as another specific example of the present invention, by preparing a coke bed containing a suitable material for filtration purposes, the sulfur filter 15 can be installed in the gas generator itself.

Since the gas coming out of the sulfur filter 15 is substantially higher than the temperature required for the production of sponge iron, the temperature is mixed with a suitable ratio of gas cooled and washed in the flow section 10 so that the temperature is suitable for manufacturing. It is adjusted to 750-1000 degreeC, Preferably it is 825 degreeC. On the other hand, the separation and mixing mechanism may be used to mix the gas coming from the gas generator and the flow section 10, and the upper portion of the gas generator 11 so that some or all of the flow section 10 can be used as the mixing chamber. Can be introduced.

Substantial technical advantages are obtained by using other methods in the device of the present invention. In this regard, gas evolution can occur at temperatures at which ash is easy to handle and can form slag that can be taken out without causing interruption of the process. The hydrogen content in the reducing gas can be adjusted to an amount suitable for the reduction process by continuously injecting water and / or oxygen into the gas generator. The combination of scrubbing and gas evolution at increased temperatures also offers a high possibility of balancing the amount of gas in the system and controlling the reduction temperature.

At the same time, the energy efficiency is satisfactory because the energy supplied by the plasma generator is almost completely used in the process (i.e., temperature control is performed by adding a cooled recycle reducing gas rather than removing heat from the system).

The consumption price per tonne of sponge iron produced in the test scale is as follows:

Electric energy: 820kwh

Coal Powder: 172kg

The process according to the device of the invention is also very simple to control. A simpler and more efficient control of the entire process can be achieved by the generation of plasma gas by premixing coal dust and water applied in an accurate proportion, preferably in a stoichiometric proportion. This premixing of coal dust and water makes it easy to inject the mixture in the form of a coal-water emulsion.

If there is a difficulty in combining ash from the solid reducing agent in the slag layer, additives such as alkali metals and chokes which affect the properties of the slag (ie melting point, sulfur absorption, etc.) can be used. Such additives are preferably mixed with the solid reducing agent. On the other hand, a suitable gel-forming material may be added to stabilize the coal-water mixture, and oxygen may be supplied to the gas generator 11 in the form of oxygen gas instead of water.

Claims (1)

It is for producing iron sponge by continuously reducing iron oxide, and the reactor (1) for reacting iron oxide and reducing gas mainly composed of CO and H ₂ , and the upper part of the furnace for removing the reaction gas from the reactor (1) connected to the outlet (6) and a CO ₂ scrubber and a minute to separate the washed reaction gas flow into two parts (9, 10) and the engine, a gas with a solid reducing material filled generated for removing CO ₂ in the reaction gas in the A plasma burner 12 which is installed at a lower portion of the shaft and the gas generating shaft to receive and heat one of the two flow units 9 and 10, a jet sprayer 13 to inject an oxidant into the heated reaction gas, and a heated reaction. A gas generator 11 composed of an injector 13a for injecting powdery auxiliary reducing agent into the gas to produce an intermediate gas mixture mainly composed of CO and H ₂ , and a sulfur filter for removing sulfur from the intermediate gas mixture (15), a mixer which mixes the reaction gas and the intermediate gas mixture of the other one of the two flow parts 9 and 10 and adjusts the mixture to obtain a final reducing gas; Sponge iron manufacturing apparatus, characterized in that consisting of the inlet (4) to be injected into the lower portion.

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