KR860000140B1 - Apparatus for manufacturing sponge iron - Google Patents

Abstract

This apparatus deals with the manufacturing of sponge iron by the continuous reduction of iron oxides in a shaft utilizing recirculation gases. Reduction gas is removed from the shaft furnace (1), substantially cleaned of all CO2 and H2O, and then divided into two flow portions. One of the flow portions is passed to a gas generator (11) comprising a plasma burner (12). A reducing agent, such as pit coal, is injected together with an oxidant into the hot gas from the plasma burner, so as to form a gas mixture which is comprises of CO and H2.

Description

Sponge Iron Manufacturing Equipment

Process schematic showing 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 the production of spongy iron by continuously reducing iron oxide in a shaft using a recycle gas.

At present, although coal is the most abundant and inexpensive source of energy, it has been used only to a very limited extent as a reducing agent in the manufacture of sponge iron. This situation persists despite the close relationship between price and energy content for coal.

Conventionally, a conventional apparatus for producing sponge iron using coal as a reducing agent uses a coal combined with coal gas on the basis of partial combustion, and the disadvantage of this apparatus is that it has a very high facility cost for gasifiers and exceptionally low. There is a lot of energy consumption.

Disadvantages and various problems in the apparatus can be solved and complemented by the apparatus according to the present invention. In other words, the apparatus according to the invention is a reactor for reacting iron oxide with a reducing gas mainly composed of several CO ₂ H ₂ , an apparatus connected to the upper part of the shaft for removing the reactive gas from the shaft, and removing the CO ₂ from the above reactive gas A scrubbing mechanism, a gas separating the scrubbed gas from at least one of the two flows, a plasma burner and a gas heated by a plasma burner with solid reducing agents and oxidants to produce an intermediate gas mixture consisting mainly of CO and H ₂ . A gas generator, which receives at least one of the two flows, localized by an injecting mechanism, a mixing mechanism for controlling mixing the intermediate gas mixture with the reaction gas of at least one of the two flows above to obtain a reducing gas, And a mechanism for introducing reducing gas into the lower part of the shaft. An apparatus for manufacturing a reducing gas for the sponge iron produced by the reduction.

In the apparatus, the reducing gas is mainly composed of CO and H ₂ , and in addition to the reaction gas from the furnace sent countercurrent to the iron oxide and produced from a solid reducing agent (eg coal, pit cool). It is generated from the recycle gas as the gas of the plasma generator with the help of. 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 reducing agent reacts with the reducing agent to form a mixture of CO and H ₂ with water injected into the hot gas stream exiting the plasma generator. 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 exiting the gas generator is mixed with at least another stream of cleaned 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 1,300 to 1,500 ° C. It is also preferred to mix the final gas mixture with the second stream prior to feeding the bottom of the shaft to bring the temperature within the range of 700 to 1,000 ° C.

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

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

Reduction of the mass to be oxidized is carried out in the shaft 1. The iron oxide mass is fed into the shaft via a sluice valve 3 and is treated by a scented flow of hot reducing gas consisting primarily of carbon monoxide and hydrogen gas supplied from the bottom 1 of the shaft 1. Sponge iron products are discharged through the outlet (4) in the lower part (1) of the shaft (4), the reducing gas reacted by 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 the relatively high content of CO and H ₂ , but the content of CO ₂ and H ₂ O should be reduced to less than 5% for reuse as reducing gas. This can be achieved by sending gas to scrubber 7 (CO ₂ / H ₂ O cleaning). When the gas passes through this scrubber, the reaction products CO ₂ and H ₂ O are removed and the amount of gas in the actual scrubbing is balanced to avoid ignition of the gas. In addition, the scrubber 7 may contain monoethanolamine as an 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 to carry out the process and divided into at least two flow sections 9 and 10.

The flow section 9 is known to have its temperature and enters the gas generator 11 where gas of fish meal is generated from a solid reducing agent, preferably coal and water. The gas stream 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. Most of the energy source, namely, coal gas, is treated with an oxidant, preferably water, and supplied to the gas generator 11 through the jet 13 so that coal powder and oxidant react to form CO and H ₂ . Penetrates into the hot gas stream from 12). In order for the reaction to occur sufficiently, the particle size of the coal powder is preferably 20 mesh, preferably 100 mesh.

When supplying energy into the gas generator 11, the amount of supply is adjusted so that the ash present in the coal dust can be applied to the slag 14 which can be removed in liquid or solid form at the bottom of the gas generator 11. On the other hand, it is preferable to select a temperature range of 1,500 ° C to 1,500 ° C because of the presence of ash.

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

Since the gas from the sulfur filter 15 is substantially higher than the temperature required for the production of sponge iron, the gas is mixed with a suitable proportion of the gas cooled and washed in the flow section 10 so that the temperature is suitable for manufacturing, that is, 750. To 1,000 ° C. and preferably to 825 ° C.

Substantial technical advantages are obtained by using the method according to 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 an 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 into the gas generator. The combination of increased temperature cleaning and gas generation 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 scis).

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

Battery energy: 8200kwh

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 whole process can be achieved by the generation of plasma gas by premixing coal dust and water added 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 coal-emulsions.

If there is a difficulty in combining ash from the solid reducing agent in the slag layer, additives such as alkali metals and chokes may be used that affect the properties of the slag (ie, melting point, sulfur absorption, etc.). Such additives are preferably mixed with the solid reducing agent.

On the other hand, an appropriate gel former can be added to stabilize the coal-water mixture and oxygen can be supplied to the gas generator 11 in the form of oxygen gas instead of water.

Claims (1)

(Correction) It is for producing sponge iron by continuously reducing iron oxide. The reactor 1 mainly reacts reducing gas composed mainly of CO and H ₂ with iron oxide 2, and reactant gas from the reactor 1 An outlet 6 connected to the top of the shaft for removal, a CO ₂ scrubber 7 for removing CO ₂ from the reaction gas, and a branch pipe separating the cleaned reaction gas into two flow sections 9 and 10. And a plasma burner 12 which receives and heats one of the two flow units 9 and 10 and a jet sprayer 13 for injecting a solid-reduced material and an oxidant into the heated reaction gas. A gas generator 11 for producing an intermediate gas mixture consisting of CO and H ₂ , a sulfur filter 15 for removing sulfur from the intermediate gas mixture, and the other one of the two flow sections 9, 10. Mixing reactant and intermediate gas mixtures and their horns The adjustment to the mixing that takes the final reducing gas, sponge iron producing apparatus, characterized in that consisting of the inlet (4) for injecting said reducing gas in the lower portion of the shaft tunnel (1).

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