CS203988B2 - Method for the continuous gasification of solid and/or liquid materials,containing hydrocarbons and device for making the method - Google Patents

Abstract

1498318 Gasification of carbon- and/or hydrocarbon-containing substances EISENWERK GES MAXIMILIANSHUTTE mbH 7 May 1976 [9 May 1975 10 May 1975 (3) 4 Feb 1976] 18728/76 Heading C5E Solid and/or liquid carbon-containing and/or hydrocarbon-containing substances are continuously gasified in a bath of molten iron in a refractory-lined reaction vessel, by passing them together with oxygen or a free-oxygen-containing gas into the bath through one or more nozzles which are mounted in the refractory lining of the vessel below the surface level of the bath, and which thereby wear away at an equal rate with the lining. Fig. 7 shows a suitable reaction vessel in combination with an installation for desulphurizing the slag formed during the process. Vessel 21 contains molten iron 22 through which is passed via nozzle 23 most preferably oxygen and particulate coal. The slag 24 that is formed flows through an outlet passage 25 in which is incorporated a settling chamber 26 for separating out droplets of iron, into the desulphurizing vessel 27. The iron flows back into vessel 21 through a passage 28. Oxygen or oxygen-containing medium is fed into vessel 27 through a nozzle 29 to convert the sulphur in the slag to sulphur dioxide, which is removed. By means of gas lift 30, the slag is pushed back to the main vessel 21 through a passage. A proportion of the slag can be continuously withdrawn from the circuit. The gas obtained consists largely of carbon monoxide and hydrogen and may be used as reduction gas for metallurgical purposes.

Description

The invention relates to a process for the continuous gasification of solid and / or liquid substances containing carbon and / or hydrocarbons in an iron melt reactor, to an apparatus for carrying out the process and to using the gases obtained.

A method is already known in which coal and oxygen or oxygen-containing gases are blown into an iron melt to produce a reaction gas consisting essentially of carbon monoxide and hydrogen (U.S. Pat. No. 3,526,473 and U.S. Pat. No. 3,533,739). In this case, coal in the form of pulp is supplied to the iron melt by means of a blown, chilled water which leads from above to the metal melt, below the surface of the iron melt. At the same time, oxygen and water vapor are introduced into the metal melt, also below the surface of the second lance. The substantial disadvantages of such nozzles will be pointed out later.

In the known sulfur-retaining slag production process, slag-forming substances, preferably lime, limestone and dolomite, are added to the iron melt. The slag absorbs the sulfur contained in the coal, producing a sulfur-free gas of about 70 to 80% carbon monoxide and about 15 to 25% hydrogen.

However, this known method has proved to be virtually unusable. There are two reasons for this.

On the one hand, the lances for adding the reactants below the surface of the melt, including the necessary shifting and regulating devices, represent a hitherto unsolvable problem. Naturally, the gasification process can only be used on an industrial scale if it is economically interesting if it can be operated safely and continuously for a relatively long time in operation. Until now, this requirement has not been met by an iron melt reactor of the type described.

Until now, it has not been possible to create gasification lances that operate without faults for several days. While in the LD process oxygen is blown onto the iron melt, it is necessary for the gasification of the lances to be immersed in the bath when gasifying the fuel. Otherwise, the carbon-containing and / or hydrocarbon-containing substances would be subjected to various reactions, such as a cracking process, thereby causing undesirable carbon black formation. For high-performance iron melt reactors, which are desirable for economic reasons, it is necessary to take into account the relatively large melt movement and to consider a sufficiently high gas space. For this reason, it is necessary to provide several meters long nozzles which are subjected to extremely high mechanical stresses due to the considerable melt movement (the specific weight of liquid iron corresponds approximately to the specific weight of solid iron, so that very high forces are exerted). This great mechanical stress cannot withstand several meters long blowers.

Another substantial drawback of the lances is that, at the required immersion depth, they are subject to extremely high wear as a result of the flow coming from the lances, where the refractory lining of the iron-melt reactor being impinged upon the flow.

Due to the intensive movement of the melt, the refractory sheathing, optionally provided for the protection of the lances, is subject to increased mechanical stress as well as increased attack by chemical reactions with slag and erosion.

Intensively cooled nozzles, such as water-cooled nozzles, have the serious drawback that too much heat is removed from the process itself.

The lances must be guided from above by a thick layer of slag, which gives rise to other problems, such as freezing of the slag lumps.

Finally, rapid replacement of the device is not possible without disturbing the gasification process, since a sufficient sealing of the iron-melt reactor against the introduction of undesirable false air has proven impractical during the exchange. However, if uncontrolled amounts of air reach the iron melt reactor, there is an increased risk of explosion in addition to their interfering effects on the gas composition.

Furthermore, in the known process, the entire slag management is difficult to control, since relatively large amounts of sulfur-rich slag must be removed and replaced by the addition of lime. In addition to the undesirable transport of material, the heat losses caused by this have proved to be the most unfavorable.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a process and apparatus that allows continuous gasification of solid and / or liquid materials containing carbon and / or hydrocarbons in an iron melt reactor without interruption for a long time and in a safe manner.

The invention is based on the finding that this problem can be solved by introducing the reactants, namely the carbon-containing and / or hydrocarbon-containing substances and the oxygen-containing or oxygen-containing medium, through the nozzles arranged in the iron melt reactor below. surface of the melt in the refractory lining, into the iron melt.

Surprisingly, it has been found that the use of nozzles arranged in an iron melt reactor below the melt surface in a refractory lining, as opposed to the known lance devices, ensures a long-term failure-free operation and particularly pure gases are obtained.

The principle of the process for the continuous gasification of carbon and / or hydrocarbon-containing solids and / or liquids in an iron melt reactor according to the invention is characterized in that the reactants, on the one hand, the carbon-containing and / or hydrocarbon-containing substances, and containing oxygen, is introduced separately into the melt below the surface by nozzles at the point of contact of the refractory lining with the melt.

Coal and / or heavy oil and / or oxygen are used as reactants.

Oxygen and / or oxygen-containing media are surrounded by a protective environment consisting of gaseous and / or liquid hydrocarbons or a hydrocarbon-containing media.

The reactants as well as the optionally granular slag-forming substances are introduced together through at least one nozzle.

In an alternative embodiment of the process, the reactants are introduced into the iron melt separately by at least one nozzle.

The oxygen is surrounded by hydrocarbons and / or a hydrocarbon-containing environment.

The substances to be gasified, in particular coal, are fed to the iron melt reactor together with gaseous or liquid hydrocarbons or an oxygen-containing medium.

In an alternative embodiment of the process according to the invention, the substances to be gasified, in particular coal, are already mixed with oxygen or an oxygen-containing medium before entering the iron melt.

The reactant streams, preferably the gasified species, are imparted a forced angular momentum with which the reactants leave the nozzle and enter the iron melt reactor.

The reactants are introduced into the iron melt continuously or intermittently for any length of time.

The slag-forming substances, preferably lime, are fed into the iron melt in admixture with the substances to be gasified.

Proportions of energy-rich coal and / or unbound carbon, such as coke, are mixed with the substances to be gasified with low energy value.

The low energy substances to be gasified are fed to the iron melt reactor, dried and / or preheated.

Aluminum, calcium carbide is admixed to the low energy value substances to be gasified, either individually or in any mixtures.

In order to increase the temperature and / or control the temperature of the iron melt, energy-rich coal, unbound carbon, aluminum, silicon, calcium carbide, either individually or in any mixtures, are fed to the latter independently of the substances to be gasified.

The iron melt reactor is operated at positive pressure and the gasification is carried out at a temperature between 1350 to 1450 ° C.

The resulting reducing gas is cooled after leaving the iron melt reactor by introducing an inert gas.

Sulfur-rich slags are transferred from the liquid iron reactor to the reaction vessel there, with the introduction of oxygen or an oxygen-containing medium with or without an inert gas addition, and then the liquid is returned to the iron melt reactor.

The sulfur content of the desulfurization slag is kept below the sulfur saturation value in the iron melt reactor.

The sulfur content of the grinder in the iron melt reactor is maintained at about 1%.

The temperature of the slag in the desulfurization reaction vessel is 1350 to 1450 ° C.

The invention further relates to an apparatus for carrying out this method. The principle of the device consists in that at least one nozzle consisting of concentric tubes is arranged below the surface of the iron melt in the refractory lining of the iron melt reactor for continuous gasification of solid and / or liquid substances containing carbon and / or hydrocarbons. The nozzle consists of a central tube and two concentric tubes.

In an alternative embodiment, the nozzle consists of four concentric tubes.

In another embodiment, the nozzle consists of supply channels formed as annular slots and a solid inner nozzle core.

At least one nozzle supply channel is provided with guiding elements generating a pulse torque.

For each reactant and each environment, at least one channel is provided in the nozzle for transport.

The at least one annular gap is shortened for stirring the reaction. the components before the mouth of the nozzle inside the nozzle.

Two separate reaction spaces are arranged in the gas space, arranged as converters, one reactor being configured to melt the iron and the other forming a reaction vessel for desulphurization of the slag and the two reaction spaces being connected to each other by two transport channels. slag, namely the slag removal channel and the slag return channel. The discharge channel arranged between the iron melt reactor and the desulfurization reaction vessel has a calming space.

The apparatus is provided with a gas lift for conveying the desulphurized slag from the reaction vessel for desulphurisation of the slag to the slag return channel.

The slag return duct is provided with an overflow to continuously withdraw the desulfurized slag.

The gases produced by the process according to the invention find use as a reducing gas for metallurgy, in particular for the reduction of iron ore.

With the method according to the invention, continuous operation can be maintained for a considerably longer period without faults than in the known method. In addition, this method has the advantage that no gas-tight and, in addition, a certain movement permitting operation in the iron melt reactor is required, and thus, in addition to increasing operational safety, the risk of explosion by the incoming false air is reduced.

The process according to the invention can produce a sulfur-free gas with a composition of about 50 to 95% of carbon monoxide and 5 to 50% of hydrogen. Typically, the carbon monoxide content is between 60 and 80% and the hydrogen content is between 15 and 40%. The composition of the gases obtained naturally depends on the substances containing carbon and / or hydrocarbons used. When using hydrocarbons, the hydrogen fraction of the gas obtained is higher than with conventional types of coal. U. In the conventional coal, the gas generally contains 60 to 80% carbon monoxide and 15 to 25% hydrogen. When using fuels that consist essentially of carbon, the hydrogen content could theoretically be reduced to 0. Depending on the protective environment used, the gas produced from gaseous and / or liquid hydrocarbons or the medium containing hydrocarbons normally contains 5% or more of hydrogen.

In the process according to the invention, all kinds of coal which can be purchased as well as coke are suitable as feedstock for gasification in the process according to the invention.

However, the treatment of relatively pure, energy-rich species such as anthracite and coke is without problems, since the proportion of slag-forming accompanying substances is less and no special measures are necessary in relation to the heat balance of the iron melt reactor. Given the favorable purchase costs, energy-poor coal types, such as brown coal, bloated brown coal and bituminous coal, which are mainly sold under the name 'long-flame coal', are of great importance.

The carbon or carbonaceous substances are preferably used in finely divided form.

Gasification of hydrocarbon-containing substances is of great importance. In the distillation of crude oil, in addition to well-settling, easily volatile fractions, heavy oil is also obtained. The evaluation of the fraction of this heavy oil is crucial for the economy of the entire mineral oil industry. The heavy oil fractions are further processed at this time mainly into bitumen and asphalt or cracked to special boiling fractions by special methods. Cracking methods, however, require expensive investments and are on the edge of economy.

Attempts to use the heavy oil fraction as a starting material for other chemical processes have resulted in technological difficulties, which have so far failed to use the most common methods in large scale operations. This is primarily due to the significant formation of soot in the gasification of heavy fuel oil. Until now, the formation of carbon black could only be countered by accepting a higher oxidation degree of the reducing gas produced from the heavy oil fractions. Furthermore, in particular, the desulphurization of the crude oil or of the gases produced therefrom is particularly problematic. Sufficient desulphurisation is, however, essential for the unrestricted use of these gases, just to meet the requirement of non-polluting the environment.

By means of the process according to the invention, it is now possible to gasify liquid hydrocarbons of various viscosities on an industrial scale up to a pasty consistency, in particular a heavy oil fraction, and to produce a gas having a particularly low sulfur content and a low oxidation degree.

The hydrocarbons to be gasified are preferably preheated to ensure trouble-free transport to the nozzles and nozzles. This is particularly advantageous for high viscosity heavy oil fractions. The pasty hydrocarbons are either preheated to temperatures such that they can be conveyed in the form of liquids or are supplied to the nozzles by special conveying devices.

The second reaction partner is preferably oxygen, preferably in technically pure form. In addition to oxygen, oxygen-containing environments, in particular air and hot wind, in particular oxygen-enriched, are suitable.

The nozzles arranged in the refractory lining of the iron melt reactor below the surface of the iron melt can be arranged in the bottom and / or side wall of the iron melt reactor wall.

The nozzles preferably consist of a plurality of concentric tubes. For example, three, four or more concentric tubes may be provided.

According to the invention, the nozzles arranged below the surface of the melt in the refractory lining of the iron-melt reactor are protected against rapid wear on the masonry by enclosing the oxygen and / or oxygen-containing environment with a gaseous and / or liquid hydrocarbon environment or environment containing hydrocarbons. For example, methane, ethane, propane, butane, various oil qualities, in particular light fuel oil and methanol, have proved to be suitable protection media, either singly or in any mixtures.

It has proven to be particularly advantageous to feed the reactants and optionally fine-grained slag-forming substances at the same location, i.e. together with the same nozzle, into the iron melt below the melt surface. A plurality of such nozzles can also be used, through which the reactants are introduced together and which in this case are evenly exhausted. The introduction of the reactants at the same site provides the advantage that rapid dissolution of the melt causes rapid dissolution of the carbon in the iron avalanche. For this reason, it is possible, for example, to choose a larger grain size of the blower dust than is possible with separate feeding of the reactants. A further advantage which results from the co-introduction of the reactants consists in the lowering of the temperature in the so-called oxygen focus, ie immediately before the nozzle orifice. This again leads to a reduction of the iron evaporation.

Preferably, the reactants in the nozzle are fed into the iron melt in the iron melt reactor by a plurality of channels, preferably an annular gap, in an alternate and arbitrary order, while seen from the center of the nozzles the annular oxygen supply gap is surrounded by a hydrocarbon / or hydrocarbon-containing environments.

Furthermore, it is advantageous to divide the substances to be gasified and / or the oxygen or oxygen-containing medium within the nozzle into a plurality of streams so that, on the one hand, an intensive reaction occurs between the reaction partners and a part of the carbon and / or hydrocarbon to reduce the temperature of the focus. This can be done, for example, by means of a nozzle consisting of a plurality of concentric tubes in which, for example, coal dust is blown inside, in one circumferential annular slot carbon again. In this embodiment of the nozzle, the oxygen beam is surrounded both inside and outside the hydrocarbon-containing protective environment.

Furthermore, separate introduction of the hydrocarbon-containing shielding gas can be avoided when the hydrocarbon-containing environment is used as a carrier gas for conveying the coal dust. The same effect can be achieved by suspending coal dust in a hydrocarbon-containing liquid.

When using hydrocarbon-containing substances for gasification, a protective environment consisting of gaseous and / or liquid hydrocarbons or a hydrocarbon-containing environment can also be dispensed with.

Suitable feed methods using a hydrocarbon for gasification are, for example, as follows. Heavy oil is blown through the inner nozzle tube, followed by the oxygen annular gap and the liquid or gaseous hydrocarbons through the annular gap. Using four concentrically arranged tubes, oxygen can be supplied through the inner tube, followed by a heavy oil through the annular slot, then oxygen through the annular slot, and a protective medium consisting of liquid or gaseous hydrocarbons through the outer annular slot.

In order to improve the conversion between the reactants, this is particularly important in large plants in which more than 10 tons of fuel are gasified per hour and favorable when the diameter of the nozzle system increases and the nozzle core is formed as a solid body. In this nozzle form, all reactants are fed into the melt by concentric slits. In practice, it has proved to be effective when the slot width is one tenth of the diameter of the ring. In this way, better stirring of the reactants is achieved. In such a nozzle, for example, heavy oil may be introduced in the inner annular slot, oxygen in the subsequent annular slot, and a liquid or gaseous protective medium may be introduced in the outer annular slot.

Sufficient swirling can be achieved, for example, by incorporating guiding elements into the annular slots of the nozzle 203988, preferably into those which serve to guide the substance to be gasified, which impart momentum to the outgoing stream.

Substances to be gasified and oxygen or oxygen-containing media. they can be mixed before they enter the iron melt. For safety reasons, this mixing should be carried out near the iron melt, preferably only inside the insertion nozzle.

The reactants may be further introduced. into the iron melt by two or more separate nozzles. If a hydrocarbon is to be used as the substance to be gasified, it is not necessary to use a multiple nozzle for separate introduction. concentrated pipes for hydrocarbon. Rather, a single nozzle may be used. tubing. On the other hand, for the separate introduction of oxygen, a nozzle consisting of at least two concentric tubes is required in order to surround the oxygen stream with a protective environment.

The supply of slag-forming substances in the bottom of the iron melt reactor can be accomplished in various ways to achieve the formation of slag-inducing desulphurisation on the iron melt. For example, slag formers, preferably lime dust, with or without limestone or dolomite, can be introduced into the oxygen stream. Another. The process comprises mixing the finely divided slag-forming substances with a finely divided coal or hydrocarbon prior to addition to the melt-iron reactor and introducing the mixture together.

The desired continuous, uniform gasification over a long period of time can be limited by the resulting concentration differences between the slag and the iron melt and possibly in the iron melt.

These concentration differences lead to changes in gas evolution and gas composition. These problems can be overcome by the pulsating addition of reactants. With the help of short-term pulsating additions of the concentration components, normal operating conditions can be restored very quickly. In the most frequent cases, ten pressure surges per minute are sufficient. The frequency of pressure surges may, however, vary as desired. These can also be used for a certain period of time. In order to improve the reaction of the components, it is also possible to work continuously with a pulsating addition. In this case, a minimum ambient pressure is set in the insertion nozzle which. it is only slightly higher than the ferostatic pressure, including the pressure above the melt in the iron melt. The resulting pressure environment is then periodically increased up to a maximum of five times.

In continuous gasification, it is essential that the iron melt is maintained at the desired temperature. Cooling the iron melt has the greatest adverse effect on the gasification and can result in the desired gasification being no longer achieved. This problem . occurs particularly when using substances containing carbon and / or hydrocarbons,. at which. the reaction does not take place. gasification already. exotermě. . On . second. The side is just using .energetically. poor. fuels, for example. energy - poor coal,. as . brown coal, or energy-poor fractions. heavy. oil based. favorable. acquisition costs. to these materials of considerable economic importance.

It would be obvious. to bring. at. use of energy-poor fuels additionally necessary consumption. energy. from the outside, for example by an arc or induction. heating,. usually. . used in. production. steel. . Like -hope. and .. preferably would further .... was coming. in regard . burn part of the recovered gases; and. in this manner ' . to bring the necessary energy. It showed. se. but,. that the nominal energy supply cannot be realized either by an additional heating device or by an afterburner. in the melt. iron. This can probably be derived from. high energy density in. melt .. iron.

S. the surprise was. found to be. possible problem to solve by contrasting with. described options. se. can. temperature drop of iron melt. prevent. by. that is. melt oxidation process. iron supply. themselves energy richer. substances.

At. use of coal types that. at. . their gasification would. led to. cooling the melt. iron, for example, these treatments and / or reactions are possible. so. Modify,. that. in the process of gasification in a melt reactor. . irons. se. reach. without. external. . supply,. .energy. surplus. . heat.

One option. rests. v ... tom,. that. coal with low calorific value. . dries. or. preheats and then is introduced. to. Reactor s. iron melt.

Another possibility is that. se energeticky. adds carbon to poor coal. For example. se. they can. use various energy-rich coal, for example anthracite. It has proved to be advantageous. use . unbound. carbon, such as coke.

It is particularly advantageous to be economically advantageous. showed to add melt. .iron. additional amounts of carbon. with benefit . of coke. The coke can be introduced, for example, in the mold. powder together with substances,. that should be gasified. This one. se. can add to. melt from above in lumpy. form. . Pro. .. reduction. the required amount of coke is. preferred coke. · Preheat.

Next. can be fed. to. .Melt iron continuously, substances of which:. the oxidation reaction proceeds strongly. exoter.micky. . . Advantageously, they can do this. use . substances ,. . which . exhibit a high thermal coloration and which. lead to products. oxidation, which have a favorable effect on the composition. slags. . So. may . for example, to blow aluminum, for example. silicon. together with substances that. to gasify. . or separately from them. . For example,. can add 10. g. bring aluminum / kg coal into the melt. . iron about. 75 cal. Calcium carbide, which reacts in the iron melt, is particularly suitable. oxide. carbon monoxide and. kys11

0 3 9.8.8 Calcium lichen. Carbon monoxide. Yippee . the desired gasification reaction product, while calcium oxide is the conventional material used for desulfurization slag. Thus, the use of potassium carbide neither gas nor slag. do not burden with undesirable substances.

The supply of said or similar heat transfer media can be carried out either as an admixture to the substances to be gasified, of low calorific value, or separately from them.

V. e. in gasification of substances. A low caloric value has proven to be very advantageous to introduce a certain proportion of high-temperature substances, for example aluminum, silicon and / or calcium carbide, to introduce iron melt temperature separately from the normal introduction of reaction partners into the iron melt. Hereby. it is possible to regulate it directly. the temperature of the iron melt. If there is a risk that the temperature of the iron melt will decrease, it will increase. supply of heat transfer medium and vice versa, at increasing temperature. Melt iron, reduced.

Inexpensive coal types as well as oil fractions could be in. as a result of their high sulfur content, it is difficult to access economically. Content . . The sulfur in particular leads to increased corrosion of the parts of the apparatus which come into contact with the sulfur and in particular of its gaseous reaction products, as well as the contamination of the environment with the resulting sulfur-containing waste gases.

The method of the invention. however, it creates the possibility to convert such cost-effective fuels into valuable products.

Sulfur,. contained in the fuels are captured by the sulfur-absorbing slag that floats on the melt during gasification in the iron melt reactor. irons.

A substantial proportion of this sulfur is absorbed. slag can be removed by:. that it is liquid, sulfur. The rich slag is transferred in the liquid state from the reactor. with iron melt. to. reaction vessels, there with the introduction of oxygen or oxygen-containing media with or without an inert gas. desulphurization, then desulphurization. in liquid. condition leads. back to the iron melt reactor.

In this way it is possible to gasify. in the reactor. with molten iron high-content substances. sulfur operationally safe .. a. economically for obtaining. maximum desulphurized gas. This further eliminates the contamination of the surrounding gases with sulfur-containing gases. In addition, this. The way of working here has the advantage of being avoided. return. slags to. Reactor s. iron melt large heat losses. . Desulphurisation in the reaction vessel, which is completely separated from the iron melt reactor in the gas space, is carried out. preferably by introducing oxygen below the surface of the slag bath. S. advantage . with oxygen. feeds and / or downstream. . the side wall area of the reaction vessel to make a path. current. · Keep large in the slag and. this has made it intense. desulphurisation. Separation of sulfur from slag has been shown to be favorable,. when an inert gas is added to the oxygen or is simultaneously separated from the oxygen. oxygen is introduced into the slag below the melt surface. The nozzle for introducing oxygen or an environment containing oxygen and inert gas may be constructed, for example, from two concentric tubes, the oxygen being guided through the inner tube and the inert gas through the annular gap.

For example, air can be introduced into the reaction vessel to desulfurize the slag. The air can be cold or preheated, depending on the process heat balance. For example, the supply of hot wind from blast furnaces with or without cold air has proven to be useful.

It has proven advantageous to keep the temperature in the iron melt and the desulfurization reaction vessel approximately the same. Temperature in the melt reactor. The iron can be controlled within wide limits by the addition of substances which react to absorb heat or release heat. In the desulfurization reaction vessel, the temperature can be influenced by the oxygen content of the gas mixture, its temperature and the amount thereof. In practice . the temperature in the iron melt reactor and the reaction vessel for the desulphurisation of the slag has been found to be about 1350 to 1450 ° C. This temperature range is. however, it may exceed at least 100 ° C or at least. 100 ^Q C lower. Depending on process parameters. the temperature may vary and temperature differences between the iron melt reactor and the slag desulphurisation reaction vessel are also possible.

The sulfur content of the reactor can be desulphurized. with melt iron to keep relatively low. This makes it possible to use. slag less, basic. While they normally use alkalinity. (CaO: SiO2) in the range between 1 and 3, this method allows sufficient desulfurization even at basicities of, for example, 0.8 and lower.

Due to the low alkalinity of the slag in the interaction of the ash components of coal, which contain generally considerable. amount of alkali, resulting in deep melting points of the desulfurization slag. Again, this is an important prerequisite for. low. operating temperatures of the process of the invention.

Furthermore, the low alkalinity of the desulphurisation slag requires only a small addition of lime in order to maintain the desired slag composition while continuously catching the coal ash. This is a priority. which has a favorable effect on the heat balance of the method of the invention.

The desulphurized slag composition is returned from the desulfurization reaction vessel to the melt reactor. and from which a part of the process cycle is withdrawn along this path, it allows the use of this slag to be used in production. cement.

In the usual way of carrying out the process according to the invention, are moving. sulfur contents of desulphurisation slag taken from the iron melt reactor. well below its sulfur saturation level. For example, a sulfur content of slag below 1% can be used. While from 20% of the slag from the iron melt reactor, the slag may show 1 to 3%. the sulfur content, but it is preferably desulphurized with contents of 0.5 to 1% already in the reaction vessel.

The low sulfur contents of the desulfurization slag allow for extremely low sulfur contents in the gas produced.

If a very low sulfur content is required in the production of gas in an iron melt reactor, for example, the sulfur content of the slag in the iron melt reactor can be maintained at 10. % Saturation solubility.

The gas obtained during desulfurization is produced. separately from the pure product gases and can, due to its high content. sulfur easily desulfurized or otherwise used, for example. for the production of sulfur.

Carbon content. preferably, it is maintained between about 1 to about 3% in the iron melt. With this. way. The work produces a gas whose contents of carbon dioxide, water and methane are extremely low. In particular cases, a very high carbon content of about 4% or a very low content of about 0.05% can be adjusted in the iron melt. carbon.

When using low carbon contents in the melt. the advantage is achieved by partial combustion. of carbon in the melt. on carbon dioxide equalizes the heat balance of the process. On the other hand, this increases the carbon dioxide content.

The gases produced in the process according to the invention are particularly suitable for use in metallurgy, for example for use in a blast furnace process or preferably for the reduction of iron ore.

Use of reducing gases for. the reduction of iron ores has recently become increasingly important. . Mainly to do this. contributed to a greater extent to the widespread distribution of the various so-called "direct". reduction processes' which are preferably used for the production of iron pellets or iron sponges. Besides, he was tentative. in the reduction of ores in a blast furnace, part of the coke is replaced by a reducing gas.

Compared to the production of reducing gases by other means, for example from natural gas, the production according to the invention has considerable advantages. Significant advantages are that expensive cleaning of the resulting gases from undesirable constituents is not necessary and gases with such a temperature and pressure that a direct charge is possible for optimal metallurgical applications. The latter aspect is particularly important. . for economic reasons.

The combination of the required purity of the gas and the desired temperature as well as the desired pressure is of prime importance. For a gas having the desired temperature and the desired pressure but showing contaminants, it would have to be cooled first, then cleaned and then reheated.

A reducing gas consisting essentially of carbon monoxide and hydrogen, optionally containing an inert gas, may be introduced. directly for metallurgical use.

The iron melt reactor is preferably designed to allow pressures such as those set. reducing gas, always according to. metallurgical use, for example, for process reduction. Operating a reactor with an iron melt. Overpressure is further prevented from leaking. places they got to. produced gas pollutants.

When using gases to reduce iron ores, the proportion of carbon dioxide and water should be as low as possible,. since even small percentages of these accompanying substances did not adversely affect the degree of efficiency in the gas reduction processes.

By the method of the invention, maximum pure gases can be obtained without the undesirable addition of carbon dioxide and water. Made reducing. gas can. contain only small amounts of iron vapor which. it does not interfere with its metallurgical use, preferably for the reduction of iron ore. Steam iron. se. stores at ore flow on this.

Reducing gases produced in an iron melt reactor. generally have a temperature of about 1350 to 1450 degrees Celsius when leaving the reactor vessel. However, the method of the invention is in this. point particularly elastic. and allows the temperature to be varied within wide limits, for example between 1250 to 1600 ° C, for example depending on. warmly. fed with substances that are. they are to be gasified by the addition of oxide. % of carbon dioxide and / or water vapor in the iron melt reactor. they convert to carbon monoxide and hydrogen, by preheating the oxygen-containing environment or by introducing substances whose oxidation. the reaction is strong. exothermally.

The gases fed directly to the metallurgical application can optionally. cool to the desired temperature when it lies lower,. than the gases they exhibit when they leave the iron melt reactor.

Cooling. of gases. can be done in the usual way. in thermal. exchangers.

An advantageous method for the controlled reduction of the temperature of the reducing gases is that:. cold inert gases such as nitrogen are admixed to these after leaving the iron melt reactor. . Particularly when reducing gases are used in blast furnaces, it has proven useful to add nitrogen. Nitrogen is often available as a cheap gas from the production of oxygen in iron works.

Addition of nitrogen as ballast gas to the reducing gas maintains the heat in the process. Furthermore, the addition of nitrogen maximally suppresses the propensity of the reducing gas, especially when it is a gas with a higher carbon monoxide content, to form soot by the so-called Boudoard reaction.

Instead of admixing the reducing gas with the correct setting. of nitrogen, the cooled reducing gas may be admixed. For example, in a number of direct reduction processes, the reducing gas leaves the reducing unit. . with low temperatures and can be separated from the carbon dioxide and hydrogen fractions without intermediate cooling by a simple chemical process. The pure but cold re203988 obtained in this way

The production gas can then be regulated. approach the reducing gas discharged from the reactor. with iron melt.

However, the gases produced by the process according to the invention are also used for. other uses.

Another possibility - use consists - for example in the use - of these. gases as fuel gas, for example power plants.

The gases produced are also suitable for their purity. various fields of the chemical industry, for example as synthesis gases for the production of methanol or as a source. of oxygen for ammonia synthesis and hydrogenation.

The invention will now be explained in more detail by way of example embodiments with reference to the drawings. Individual images. show:

FIG. 1 is a vertical section through an embodiment of an iron melt reactor;

FIG. cut. a nozzle consisting of four concentric tubes;

FIG. 3 shows a vertical nozzle consisting of three concentric tubes;

FIG. 4 is a vertical cross-section of a nozzle having only annular slits, partly with built-in elements, the supply of reaction partners and the environment;

Fig. 5 is a vertical cross-section through a nozzle with three annular slots and a fixed core, whereby a single-annular slit can be recognized as a built-in element a tape helix;

FIG. 6 shows an embodiment of a nozzle in which the reaction partners were already mixed before the molten iron inlet;

FIG. 7 is a vertical section through another embodiment of an iron-melt reactor; and FIG. 8 is a horizontal cross-sectional view of the iron melt reactor of FIG. 7.

The iron melt reactor shown in FIG. 1 consists essentially of a steel jacket 1 with a refractory lining 2. A melt is present in the iron melt reactor. - Slag 4 absorbs the proportions of ash and a large proportion of the sulfur - containing carbon - and hydrocarbons. The reaction partners are fed to the iron melt 3 by a plurality of nozzles 5 which are arranged in the refractory lining 2.

The slag-forming substances, preferably lime, with or without admixtures, are preferably also fed to the metal melt by means of nozzles. - Usually used as slag-forming substance quicklime. However, it is possible to replace quicklime, in part or entirely with limestone, to reduce the temperature, depending on the calorific value or the energy content of the substances used.

In the following description, coal dust is most often mentioned as the substance to be gasified. - It is - however. - of course that . . the coal dust can be replaced by other substances,. . to be gasified, for example with heavy oil.

.Trysky 5. in the refractory lining 2 they wear evenly with the refractory. material and are preferably constructed of concentric tubes with a circular cut-out. However, it is also possible to use tubes with. cross-section similar to -circle to. rectangular. in the form of a cross-section. However, it is advantageous for economic reasons. Use ordinary tubes, with circular cross section.

Nozzle according to. FIG. 2 is constructed of four concentric tubes 6; 7. In this case, for example, the inner tube 6 is supplied. - coal dust with carrier gas into the iron melt. . As carrier gases comes in. especially inert gases, nitrogen, carbon dioxide and water vapor are considered. Carbon dioxide and water vapor may be. at. at the same time used for regulation. temperature. An annular slot formed of tubes 7 and 8. it leads to oxygen or an oxygen-containing medium. - Both annular slits between. pipes - 6 and. 7 and between - pipes - 8. a. 9 serves. for the supply of protective environments for. nozzle. - The protective environment consists of:. gaseous and / or liquid hydrocarbons or the environment,. containing hydrocarbons. Alternatively, it may be guided through the inner tube. Oxygen, followed by a heavy oil gap, followed by a subsequent annular gap, again - a heavy oil. - Dimensions. for example, the annular slots may be selected such that main. the amount of oil transported in the inner tube, while the amount of oil in the outer annular slot is substantially smaller and serves mainly to protect the nozzle. . In the outer annular - - slit can. be conducted also gaseous or liquid - hydrocarbon, as a protective environment. for nozzle. . The supply of the various feed substances or the medium can optionally be connected.

Nozzle consisting of - three channels 10, 11,. 12 is shown in FIG. giant. . 3. The channels of such a nozzle design are. they can use reaction partners - and the environment in the following breakdown. Either be transported through the central pipe 10. oxygen, a shielding environment by an annular gap 11 and coal dust by an external annular gap 12; or with a central tube 10 and ... carbon leading through the outer annular gap. in suspension with a hydrocarbon-containing protective medium, while oxygen flows through the annular gap 11, - Alternatively, the substance to be gasified through the annular tube 10 can be guided through the annular gap. 11 oxygen and. outer ring. The slit -12 is a protective environment, for example 5% natural gas based on oxygen.

Nozzle design according to. giant. . 4, which is preferably. uses - to feed - large quantities of the substance that is. has. gasification, shows a massive - core 13th. Feed channels

14, 15, 16 have. at least partially built-in elements. In principle, the annular slots 14, 15, 16 can logically be used as channels 10, 11, 12 for supplying reaction partners and the environment. In FIG. 4, the annular slot 14 serves to convey the environment to be gasified. In this channel 14 helical built-in elements 17 are provided which impart momentum to the flow of the substance. Oxygen flows through the annular gap 15. An annular slot 16 divided into approximately circular channels serves to transport the protective environment.

Another preferred embodiment of the nozzle is shown in FIG. 5. In this nozzle, the oxygen supply is provided by an annular gap 40 whose width is substantially smaller than the diameter of the annular ring.

For example, nozzles with an inner ring diameter of 10 cm have proved to be useful, in which the width of the annular gap is about 3 mm. In such a nozzle, the substance to be gasified, for example, heavy oil, is conveyed in the annular slots 41 and 42. It is also advantageous here to select the amount conveyed in the inner annular slot 42 greater than in the outer annular slot 41. It may be advantageous to convey in the outer annular slot only a small amount of the hydrocarbon-containing compound and all of the material to be gasified are fed to the inner annular gap 42. In this nozzle design, it has further proven to impart great momentum to the oxygen flow by the spiral guide elements 43 arranged in the annular slot 40. . This leads to a rapid swirling between the oxygen, the substance to be gasified and the iron melt and causes the melt blowing behavior of the iron melt.

By using this mold, the number of nozzles required is substantially reduced. For example, as opposed to about ten simple concentric nozzles, two such nozzles are sufficient. The massive helical strip 43 can close about a quarter of the annular gap 40. By partially closing the annular gap, it is easier for the molten iron to flow into the center of the reaction medium exiting the nozzle.

A particular construction of the nozzle is shown in FIG. 6. Here, the substances 19 to be gasified, for example coal dust and oxygen 20, are mixed with each other before they enter the iron melt. In this case, the coal dust 19 and the oxygen 20 are first fed separately through the steel mantle 1 of the iron-melt reactor up to partially. of the lining 2 and there the mixing with the reaction partners takes place in the nozzle.

The pressure in the space above the iron melt may be, for example, about 5 atm when the reducing gas is intended for a blast furnace; and, for example, about 2 atm when used for the direct reduction process. The fire-retarded line feeds the reducing gas directly, but optionally with the intended intermediate cooling, to the reduction process.

Figure 7 shows an iron melt reactor equipped with a desulfurization plant. A coal melt, oxygen or oxygen-containing or lime-dust-containing medium is blown through the nozzles 23 into the iron melt reactor 21, similar to the converter, which is partially filled with the hydrocarbon-containing iron melt 22. iron melt 22. The desulphurization slag 24 flows through a drain channel 25 in which a calming space 26 for separating from the iron droplets is built into the reaction vessel 27 for the desulphurisation of the slag. The iron accumulated from the deposited iron droplets flows through the channel 28 into the iron melt reactor 21 back. The drain channel 25 runs below the level of the slag.

The calming space 26 in the slag removal channel 25 is of impor- tant importance to provide an opportunity for the portions of iron entrained from the molten iron into the slag, which mainly occur in the form of finely dispersed droplets. perfect separation. As perfectly as possible the separation of the iron fractions in the slag before the slag reaches the reaction vessel 27 for the desulphurisation of the slag is important. The proportion of metal in the slag negatively affects the desulfurization in the reaction vessel 27. The metal portions mainly reduce the desulphurisation of the slag relative to the oxygen supplied and thus make it almost impossible to control the desulphurisation of the slag. Also, the temperature in the reaction vessel 27 for the desulphurisation of the slag by the possible supply of heat through the combustion of the metal cannot be controlled within the desired limits.

The size of the calming chamber 28 can be interpreted in such a way that sufficient slag residence times in this chamber are guaranteed, i.e. the flow rate of the slag in the calming chamber 26 must be considerably reduced compared to its flow rate in the discharge channel 25. high reaction rates, it is necessary to create a calming space 26 greater than that of relatively slow coal gasification. Normally it is necessary. maintain a free flow cross-section ratio of at least 1:10 between the discharge channel 25 and the calming chamber 26.

In the slag desulphurisation reaction vessel 27, oxygen or an oxygen-containing medium is introduced through the bottom nozzle 29, which causes slag oxidation, resulting in a significant reduction in sulfur solubility and oxidation. sulfur, which is then removed as sulfur dioxide from the system.

The slag 30, which is fed with nitrogen, for example, passes the slag through the channel 31 shown in FIG. 8 to the iron melt reactor 21.

In a particular embodiment of the gas lift 30, the nozzle 29 is necessary for the desulphurisation of the slag disposed in the bottom of the masonry reaction vessel 27 so that it performs the function of the gas lift 30 and renders the specially built gas lift 30 unnecessary.

In addition, in FIG. 8, an overflow 32 is provided in the slag return duct 31 through which part of the slag is withdrawn from the circuit.

An exemplary embodiment of an iron melt reactor for producing 100,000 Nm3 / h of a gas having an approximate composition of about 25% hydrogen

20 ' and about 75% of the carbon monoxide contains 60 mt of iron melt and then a 15t slag amount. The free space in the newly lined iron melt reactor is 80 m ³ . Two nozzles 5 are arranged in the bottom of this reactor.

The nozzles 5 are constructed of four concentric tubes 6, 7, 8, 9 of stainless steel with a wall thickness of 3 mm. The essential elements alloying stainless steel are 0.4% carbon and 13% chromium. The tube 6 has a clear cross section of 70 mm and is conveyed therein with a carrier gas of 50,000 kg / h of coal with a maximum grain size of 0.5 mm to the iron melt 3. The annular gap formed of the tubes 7 and 8 has a width of 8 mm. The two annular slits for the environment, formed of tubes 6 and 7, are provided. as well as from pipes 8 'and 9 have a width of 0.5 mm and in each annular gap flow 2,000 Nm ³ / h of natural gas with a composition of 90% methane, 4% hydrocarbon C _n H _m , 3% carbon dioxide and 3 % nitrogen. 20% fine lime (CaO) is added to the coal as slag formers. The second nozzle in the bottom is - supplied with equal quantities - and reaction partners and environments.

Such an iron-melt reactor for continuous gasification of coal allows continuous, trouble-free operation for at least two months.

The resulting reaction gases can be used, for example, as follows in a blast furnace.

A blast furnace, for example with a daily production of 5000 tons of pig iron, is operated in conjunction with an iron melt reactor for

Claims (32)

SUBJECT A process for the continuous gasification of solid and / or liquid carbonaceous and / or hydrocarbon-containing substances in an iron melt reactor, characterized in that the reactants, on the one hand, the carbon-containing and / or hydrocarbon-containing substances, and oxygen, or the oxygen-containing medium is introduced separately into the melt beneath the surface - by nozzles at the point of contact - of the refractory lining with the melt. 2. Process according to claim 1, characterized in that on the one hand coal or heavy oil and on the other hand oxygen are used as reactants. 3. The method according to claim 1, wherein the oxygen and / or oxygen-containing medium is surrounded by a protective medium consisting of gaseous and / or liquid hydrocarbons or a hydrocarbon-containing medium. 4. Method according to claim 1 or 3, characterized in that the reaction components as well as the optionally fine-grained slag-forming substances are introduced together by at least one nozzle. Process according to one of Claims 1 to 3, characterized in that the reactants are introduced separately into the molten iron by at least one nozzle. 6. A process according to claim 4, characterized in that the gas is reduced. The consumption of coke in the blast furnace is about 550 kg / t pig iron without reducing gas. By using a reducing gas, 200 kg of coke / t pig iron are saved and for this purpose a total of 100-0 t of coal is gasified daily in the iron melt reactor. The reactor vessel for this application has a free volume of about 30 m &^lt; ^{3 &gt}; Thus, for a relatively large furnace, only a small additional equipment for reducing gas production is required. The temperature of this iron melt is, for example, about 1450 ° C. When determining the used reducing gas temperature in the blast furnace, the operating data of another blast furnace are taken into account. Normally, the reducing gas is fed to the blast furnace at temperatures between about 1000 to 1300 ° C. The temperature of the reducing gas of about 1100 degrees Celsius is achieved, for example, by the addition of about 20 volume% nitrogen at room temperature (20 ° C). With about 10% nitrogen by volume under otherwise identical conditions, the temperature of the reducing gas is about 1300 ° C. In reducing gas production, a direct reduction process operating at a pressure of about 2 atm requires an iron melt reactor volume of about 50% greater than described above. The optimum temperature of the reducing gas for the direct reduction process is generally between about 700 and 1000 ° C. The desired temperature of about 850 ° C can be achieved, for example, by admixing about 45 vol% nitrogen. The invention is characterized in that the oxygen is surrounded by hydrocarbons and / or a hydrocarbon-containing environment. Method according to one of Claims 1 to 6, characterized in that the substances to be gasified, in particular coal, are fed to the iron melt reactor together with gaseous or liquid hydrocarbons or an oxygen-containing medium. Method according to Claim 7, characterized in that the substances to be gasified, in particular coal, are already mixed with oxygen or an oxygen-containing medium prior to entering the iron melt. Method according to one of Claims 1 to 8, characterized in that the reactant streams, preferably the gassed substances, are imparted a forced angular momentum with which the reactants leave the nozzle and enter the iron melt reactor. Process according to one of Claims 1 to 9, characterized in that the reactants are introduced continuously or intermittently into the iron melt for any length of time. Method according to one of Claims 1 to 10, characterized in that slag-forming substances, preferably lime, are fed into the iron melt at 203988 in admixture with the substances to be gasified. Method according to one of Claims 1 to 11, characterized in that proportions of energy-rich coal and / or unbound carbon, for example coke, are admixed with the substances to be gasified with a low energy value. Method according to one of Claims 1 to 12, characterized in that the substances of low energy value to be gasified are fed to the iron melt reactor, dried and / or preheated. Method according to one of Claims 1 to 13, characterized in that aluminum, silicon, calcium carbide are admixed to the low energy substances to be gasified either individually or in any mixtures. Method according to one of Claims 1 to 14, characterized in that, for raising the temperature and / or controlling the temperature of the iron melt, energy-rich coal, unbound carbon, aluminum, silicon is introduced into the latter independently of the substances to be gasified. , calcium carbide and that)! either individually or in any mixtures. Method according to one of Claims 1 to 15, characterized in that the iron-melt reactor is operated under positive pressure and the gasification is carried out at a temperature between 1350 to 1450 ° C. Method according to one of Claims 1 to 16, characterized in that the resulting reducing gas is cooled after leaving the molten iron reactor by introducing an inert gas; Process according to one of Claims 1 to 17, characterized in that the sulfur-rich slag is transferred from a liquid-molten iron reactor to a reaction vessel there by introducing oxygen or an oxygen-containing medium with or without the addition of inert gas. and then the liquid is returned to the iron melt reactor. Process according to one of Claims 1 to 18, characterized in that the sulfur content of the desulphurisation slag is kept below the sulfur saturation value in the iron melt reactor. 20. The method of any one of claims 1 to 19, wherein the sulfur content of the slag in the iron melt reactor is maintained at about 1%. Method according to one of Claims 1 to 20, characterized in that the temperature of the slag in the desulphurisation reaction vessel is 1350 to 1450 degrees Celsius. Apparatus for carrying out the method according to Claims 1 to 21, characterized in that in the refractory lining (2) of the iron melt reactor (3) for the continuous gasification of solid and / or liquid substances containing carbon and / or hydrocarbons is below At least one nozzle (5) consisting of concentric tubes is provided by the melt surface (31) of the iron. Apparatus according to claim 22, characterized in that the nozzle (5) consists of a central tube and two concentric tubes. Device according to Claim 22, characterized in that the nozzle (5) consists of four concentric tubes [6 to 9]. Apparatus according to Claim 22, characterized in that the nozzle (5) consists of supply channels (14 to 16) configured as annular slots and a solid inner core (13) of the nozzle (5). Apparatus according to Claims 22 to 25, characterized in that in at least one supply channel (14 to 16) of the nozzle (5) there are arranged impulsomoments forming guiding elements (17). Apparatus according to one of Claims 22 to 26, characterized in that at least one channel (14 to 16) is arranged for transport in each nozzle (5) in the nozzle (5). Apparatus according to one of Claims 22 to 27, characterized in that the at least one annular gap (40) is shortened for mixing the reactants before the mouth of the nozzle (5) inside the nozzle (5). 29. The apparatus of any one of items 22 to 22 28, characterized in that two separate reaction spaces are provided in the gas space, arranged for converters, one reactor (21) being arranged to smelt the iron (3) and the other forming a slag desulfurization reaction vessel (27) and both the reaction spaces are connected to each other by two slag transport channels, namely a slag discharge channel (25) and a slag return channel (28). 30. The apparatus of any one of items 22 to 22 29, characterized in that the discharge channel (25) disposed between the iron melt reactor (22) and the desulfurization reaction vessel (27) has a calming space (26). 31. The apparatus of any one of items 22 to 22 30, characterized in that it is provided with a gas lift (30) for transporting the desulphurized slag (24) from the reaction vessel (27) for desulphurisation of the slag to a channel (28) for returning the slag (24) stream. 32. The apparatus of any one of items 22 to 22 31, characterized in that the slag returning channel (28) is provided with an overflow (32) for continuously withdrawing the desulfurized slag (24).