JPH01246311A - Production of gas and molten iron in iron bath reactor - Google Patents

Abstract

PURPOSE: To inexpensively produce gaseous fuel and to produce molten iron by supplying a carbonaceous material and iron oxide to an iron bath in an iron bath reactor and blowing gas jets contg. oxygen to the surface of the iron bath through the gas chamber in the reactor.

CONSTITUTION: Powdery coal 24 or liquid fuel contg. carbon is supplied from a nozzle 23 into the reaction vessel 20 where about half amt. of the molten iron bath 21 exists. Ores and slag forming agents are charged together with the oxygen from a nozzle 25. Further, gases 28 at least partly consisting of the oxygen are introduced from nozzles 26, 27 installed in the upper part of the reaction vessel 20 to form the gas jets 29. These gases jets are blown to the bath surface 22 of the iron bath 21 through the gas chamber 30 delineated in the reaction vessel 20. The gas jets 29 suck the gaseous fuel 31 produced from the coal, etc., and partly burn the fuel at the time of passing the gas chamber 30. The combustion heat generated by this combustion is transmitted to the iron bath 21 and is used for reducing the iron oxide in the ores. As a result, the molten iron and the gaseous fuel are obtd. without requiring the addition of the high-calorie fuel.

COPYRIGHT: (C)1989,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing combustible gas and molten iron in an iron bath reactor.

BACKGROUND OF THE INVENTION The continuous gasification of coal or other carbon-containing fuels into a gas consisting essentially of CO and H2 in iron or steel bath reactors with a slag bed has been known for a long time. According to the method disclosed in West German Patent Publication No. 2952434, oxygen is blown onto the bath surface from a blowing lance located above the bath surface of the iron bath.
A hot spray section is thereby formed. A solid carbon-containing powder is blown into this high-temperature blowing section together with a carrier gas.

Furthermore, a method is known from German Patent No. 2,520,883 in which coal or other carbon-containing fuel is blown into an iron bath below the bath surface. A gas jet consisting at least in part of oxygen is also blown into the iron bath below the bath surface, the hydrocarbon jacket serving to protect the nozzle.

Furthermore, according to German Patent Specification No. 2520868, a method is provided in which the iron bath is additionally supplied with high-calorie coal, unbound carbon, aluminum, silicon, calcium carbide or mixtures thereof, optionally separately from the gasifying coal. is publicly known. Heat is thereby supplied to the coal gasification process.

A disadvantage of these known methods is that the gasification of low-grade fuels, especially low-calorie coal, is not economically possible to date. This is because low grade fuels require the addition of high calorie fuel in order to maintain the temperature of the iron bath with these types of fuels. Furthermore, the known method does not allow the use of inexpensively available oxidizing gases, such as air.

Furthermore, West German Published Patent Application No. 2401909 discloses a known multi-throw method for producing molten iron by reducing iron ore. However, this method has the disadvantage that the gas generated can only be used for limited purposes without mixing with a high calorie gas which is disadvantageous in terms of cost due to its low calorific value.

In this method, approximately 650 kg of coal is required to produce 1 ton of iron.

C041%, CO230%, 82018%, H210%
Rough composition and exothermic IH of 1100 Kcal/m',
A gas with .

OBJECTS OF THE INVENTION It is an object of the invention to avoid the disadvantages of known processes and to use inexpensive oxidizing gases in iron bath reactors from low-calorie fuels containing carbon and/or hydrocarbons in ground solid or liquid form. This makes it possible to produce fuel gas inexpensively and at the same time to produce molten iron from materials containing at least some iron in the form of oxides, in particular by adding high-calorie fuel to compensate for the thermal balance of the gasification process. The goal is to provide a method that does not require it.

According to the invention, a solid or liquid fuel containing carbon is supplied into an iron bath reactor in which a molten iron bath is present, and a substance containing iron at least partially in the form of an oxide is supplied. Blowing a gas jet consisting at least partially of oxygen onto the bath surface of the molten iron bath through a gas chamber defined in said iron bath reactor, the gas jet sucking in the produced gas as it passes through the gas chamber. , the produced gas is entrained at the bath surface so that the heat generated by the combustion of the produced gas is transferred to the iron bath, and the heat produced by said partial combustion burns at least the iron. A method is provided for producing gas and molten iron in an iron bath reactor for smelting steel to be used at least in part for the reduction of materials containing partially in oxide form.

That is, according to the method of the present invention, a substance containing iron in bound or unbound form, such as ore, is supplied to the molten metal in the reaction vessel, and molten iron (pig iron) is produced at the same time as gas is produced. According to this feature of the process of the invention, the heat generated by the partial secondary combustion of the gas produced in the iron bath reactor is at least partially used for the reduction of iron-containing materials, especially ores.

In addition to a carbon-containing solid or liquid fuel as well as oxygen and a slag-forming agent, the molten iron in the reactor is supplied with additional substances, such as ore, which contain at least some iron in the form of oxides.

The great economic advantage of the process according to the invention is that the ore can be reduced directly with a relatively small amount of coal with low industrial outlay, and at the same time a gas is obtained which can be used in many ways. Coal (C78%, H25
%, H2O3%, ash 5%, 025%, 81% composition and exotherm IHu 7500 K cal / m
') Requires approximately 1°1t. At the same time, the approximate composition C○57
%, C0214%, H214%, 82014% and H
8 Approximately 2100 Kcal/71' of industrially used silica gas is generated.

Therefore, according to the method of the present invention, economical steel production is achieved in combination with gas production in an iron bath reactor.

For example, if a similar process is carried out without retransfer according to the invention by partial secondary combustion of the gas produced in an iron bath, then the same coal is used to produce iron 1 from iron ore. Approximately 3 tons are required. At that time, the exhaust gas has a composition of 70% CO, 21% CO, 27% H2, and 1% H2O, and the heat generation of 11 HU is approximately 2700 Kcal/m.
'is.

In the method of the invention, the ore can be introduced directly into the iron bath through the bottom nozzle or blown into the bath from above. According to an advantageous embodiment of the invention, the ore is added at least in part together with the oxygen which is blown into the bath. With this method of operation, the dusty ore is already preheated and prereduced in the gas chamber, which increases the thermal efficiency of the process. In order to further improve this effect, it is advantageous to use devices that serve to widen the jet containing the ore particles, such as devices in which the jet swirls and leaves the nozzle.

In addition to ores of various grades, pellets and briquettes of incompletely reduced ores are suitable as materials containing at least some iron in the form of oxides.

The method of the invention can be applied particularly advantageously when the gas produced can be used in the immediate vicinity as a substitute for fuel gas, for example natural gas. The partially secondary combusted gas produced by the method of the present invention has approximately the same flame temperature as natural gas, mainly due to its relatively high 00 min, and can therefore be used as a substitute for natural gas without major modification of the furnace equipment. can do.

In the method according to the invention, the gas jet passes through the gas chamber above the bath surface over as large a distance as possible. Due to the jet effect, the gas produced by the fuel gasification in the gas chamber is sucked in and entrained. This effect also occurs, for example, in the case of water jet pumps.

Since the gas jet directed toward the bath surface contains oxygen, a portion of the combustible gas generated is combusted. The heat generated in this process is transferred to the iron bath. This is because the gas jet directs the hot combustion products toward the bath surface, so that the hot combustion products come into contact with the bath surface and
This is because it imparts that heat to the bath.

By spraying jets of oxidizing gases (oxygen, air, etc.) onto the bath surface according to the invention, the thermal balance within the iron bath reactor can be significantly improved.

The method according to the invention makes it possible to use air as the gas jet. Therefore, it is not necessary to use industrially pure oxygen as in the case of known methods. Air is usually available cheaply;
It can be compressed to the required working pressure by simple means. In this case, it is particularly advantageous to preheat the air so that the heat necessary for heating the air is not extracted from the gasification process. In practice, it has been found that a preheating temperature of 300 to 400°C is appropriate. Up to this temperature, conventional conduits and circuit breaker tubes can be used, and insulation of the supply system can also be implemented economically.

However, the gas jet can also be formed from technically pure oxygen. This is particularly advantageous in the case of fuels with very low exothermic profiles. The proportion of oxygen in the gas jet is therefore largely determined by economic considerations and the grade of the fuel used.

Advantageously, the solid or liquid fuel is blown into the iron bath below the bath surface. A carrier gas such as air, nitrogen, carbon monoxide, inert gas, etc. is used for transport. It can also be installed on top.

The oxygen of the gas jet which is blown through the gas chamber onto the bath surface is consumed in particular in the combustion of a portion of the gas produced from the fuel. The actual oxygen supply for the gasification process, on the other hand, preferably takes place through a nozzle located below the bath surface. This nozzle consists, for example, of a number of concentric tubes, on the outside of which a hydrocarbon is used in a known manner to protect the nozzle.

The ratio of the amount of oxygen supplied below the bath surface to the amount of oxygen supplied by the gas jet above the bath surface can be varied within any range. For example, 80% of the total oxygen can be supplied from above by means of a gas jet and only 20% can be introduced below the bath surface, or, just the opposite, 80% of the total oxygen supplied to an iron bath reactor can be supplied below the bath surface. Alternatively, only 20% can be supplied from above by means of a gas jet. However, it has been found necessary to utilize the advantages of the invention with respect to heat balance that at least 10% of the total amount of oxygen fed to the iron bath reactor is blown onto the bath surface by means of gas jets. This ratio can go up to 100%. It has now surprisingly turned out that this oxygen in the gas jet is used for the oxidation of the fuel in the iron bath. In the usual operating method of iron bath reactors, about 40 to 90% of the total oxygen supply is supplied via the gas jet. The portion fed from above is already kept as high as possible for economic reasons. This is because this portion of the total gas volume is generally blown at a low pressure compared to the pressure required in the nozzle sump below the bath surface.

It is advantageous to direct a large number of gas jets onto the bath surface.

Spraying is performed from a large distance to the bath surface, and the impact position is approximately at the center of the bath surface. It is important that the travel distance of the gas jet flowing into the gas chamber above the bath level is sufficiently long. Usually the minimum distance between the nozzle of the gas jet and the bath surface should be about 2 m. The nozzle is placed in the refractory lining in the upper region of the iron bath reactor. The nozzle consists primarily of a single tube when blowing air or, for example, of two concentric tubes when using industrially pure oxygen. In the case of concentric tubes, oxygen flows through the central tube, and a small amount of nitrogen, carbon monoxide, inert gas, hydrocarbon, etc. (0.1 to 5% relative to the oxidizing gas) is introduced into the ring gap to protect the nozzle.

EXAMPLE Hereinafter, an example will be described in which the method of the present invention is applied to a converter-type reaction vessel having a capacity of 60 tons. Inner diameter 28 at the bottom of the converter
Ten city nozzles will be installed.

350 kg/min of return powder is blown in through two of these nozzles, the carrier gas being nitrogen, carbon dioxide or reducing gas from the converter itself. 3
Oxygen is blown in with the ore through one nozzle, and oxygen partially loaded with a slag-forming agent, such as lime, is supplied through the other five nozzles. Approximately 50% of the oxygen is introduced into the bath through a side nozzle placed in the upper cone of the converter. Coal of the above composition and Fe2O, 85% ore produce iron20 with a carbon content of about 3%.
t/h is produced. When melting 1450 kg of iron ore at the same time, the amount of oxygen required to gasify 1 ton of coal is 580 m'. C○ approx. 57%, Co, 14%, H
214%, H2O 14% composition and 2100Kcal
Coal gas or fuel gas is generated with an exothermic IHU of /m'.

It is also within the scope of the invention to configure the reaction vessel to simultaneously serve as a converter and to produce steel directly therein.

For this purpose, the carbon content during normal iron bath reactor operation is approximately 2 to
3% is reduced to about 0.05% each time before tapping, and about 20%
A partial amount of t is discharged. A quantity of approximately 50 t remains in the converter, which is then gradually carburized again by simultaneous injection of oxygen and coal with a slight excess of coal to the desired 2-3% carbon for continuous operation. In this working method, carbon is completely removed before refining, i.e. the residual carbon content is approximately 0.5~2%.
It has become clear that it is advantageous to drain the slag from the iron bath. Subsequently, the newly formed new slag, which is in equilibrium with the discharged steel bath, remains in the converter.

Next, the present invention will be explained with reference to the drawings.

The hermetically closed, essentially empty reaction vessel 20 is filled approximately half way with a molten iron bath 21, so that the bath level 22 is approximately half the height of the reaction vessel 20.

A nozzle 23 for introducing finely ground coal 24 is installed at the bottom of the reaction vessel. Furthermore, a nozzle 25 is provided at the bottom of the reaction vessel 20 for blowing oxygen together with iron ore and a slag forming agent. In practice, this nozzle 25 is surrounded by a hydrocarbon ring gap for nozzle protection.

In the upper region of the converter, two nozzles 26 and 27 are installed through the wall of the reaction vessel 20. This nozzle supplies oxygen and forms a jet 29 directed approximately toward the center of the bath surface 20. The outlet holes of nozzles 26 and 27 are approximately 2 m above the bath surface.
It is above.

The gas jet 29 passes through a gas chamber 30 above the bath surface 22 and entrains by its jet effect the gas 31 already produced by the gasification of the coal 24 . A portion of this gas is combusted by the oxygen in the gas jet 29. A portion of the combustion heat is transferred to the iron bath 21 through the bath surface 22 and is used at least in part to reduce the iron ore to produce molten iron.

EFFECTS OF THE INVENTION The process of the present invention, constructed as detailed above, enables the production of inexpensive oxidizing materials in iron bath reactors from low-calorie fuels containing ground carbon and/or hydrocarbons in solid or liquid form. By using gas, fuel gas can be economically produced, and iron ore can be directly reduced to produce molten iron.

[Brief explanation of the drawing]

The drawing is a longitudinal cross-sectional view of an iron bath reactor. 20... Reaction vessel, 21... Iron bath, 22... Bath surface, 23.25, 26.27... Nozzle, 24... Coal, 29... Gas jet, 30... Gas chamber, 31...Gas agent: Patent attorney Akira Matsumoto

Claims (1)

[Scope of Claims] (1) Supplying a solid or liquid fuel containing carbon into an iron bath reactor in which a molten iron bath is present, and supplying a substance containing at least a portion of iron in the form of an oxide; Blowing a gas jet consisting at least partially of oxygen onto the bath surface of the molten iron bath through a gas chamber defined in said iron bath reactor, the gas jet sucking in the produced gas as it passes through the gas chamber. , the produced gas is partially combusted, and the produced gas is entrained to the bath surface so that the heat generated by the combustion of the produced gas is transferred to the iron bath, and the heat produced by the partial combustion is transferred to at least one of the iron baths. 1. A method for producing gas and molten iron in an iron bath reactor, characterized in that it is used at least partly for the reduction of substances containing in the form of partial oxides. (2) The method according to claim 1, wherein the length of the gas jet in the gas chamber is greater than 2 m. (3) In particular, ores or partially prereduced ores such as pellets and/or briquettes are fed to the iron bath reactor as substances containing iron at least partially in the form of oxides.
The method described in any of the paragraphs. (4) A method according to any one of claims 1 to 3, in which a substance, in particular an ore, containing at least part of iron in the form of an oxide is blown into the molten metal together with an oxidizing gas, in particular oxygen. (5) The method according to any one of claims 1 to 4, wherein the produced iron containing carbon is refined into steel in a reaction vessel.