EP2408881A1

EP2408881A1 - Coal gasification with additional production of useful materials

Info

Publication number: EP2408881A1
Application number: EP09841670A
Authority: EP
Inventors: Heinrich Morhenn; Leslaw Mleczko; Oliver Felix-Karl Schlueter; Verena Haverkamp; Fei Liu
Original assignee: Bayer Technology and Engineering Shanghai Co Ltd; Bayer Technology Services GmbH
Current assignee: Amina LLC LP
Priority date: 2009-03-18
Filing date: 2009-03-18
Publication date: 2012-01-25
Also published as: WO2010105385A1; CN102361961A; EP2408881A4

Abstract

The present invention relates to a process for the gasification of carbon-containing compounds, characterized in that compounds are added which form carbides under the process conditions. These carbides can be used for the synthesis of useful materials such as for example acetylene.

Description

Coal Gasification with Additional Production of Useful Materials

The present invention relates to a process for gasifying carbon-containing gasification materials which is characterized in that compounds are added which form carbides under the process conditions. These carbides can be used for the synthesis of useful materials, such as for example acetylene.

Carbides of alkali metals and alkaline earth metals and processes for their production are known from the prior art (see, for example, Ullmann's Encyclopedia of Industrial Chemistry, 2005, WileyVCH Verlag GmbH & Co. KGaA, Weinheim, "Calcium Carbide").

Calcium carbide has become particularly important industrially. It can be obtained in an electric-arc furnace at 1,800 - 2,100⁰C from calcium oxide and coke. This process consumes high quantities of energy, in particular because during the production of the electricity a large proportion of the primary energy is lost. Carbon monoxide is obtained as a by-product:

CaO + 3 C -→ CaC₂ + CO ΔH²⁹⁸ + 465 kcal/mol (1)

Calcium carbide can also be produced by the direct reaction of coke with calcium oxide and oxygen (see, for example,US 2794706). In this reaction carbon monoxide is also produced as a by-product:

(3+n) C + CaO + 7₂ O₂ → CaC₂ + (n+ 1 ) CO (2)

Calcium carbide reacts with water to form acetylene:

CaC₂ + 2 H₂O → C₂H₂ + Ca(OH)₂ ΔH²⁹⁸ - 128 kcal/mol (3)

The production of sodium carbide and carbon monoxide from sodium oxide and carbon is described, for example, in US 3460925A:

Na₂O + 3 C → Na₂C₂ + CO ΔH ₂₉₈ + 329 KJ/mol (4)

Instead of sodium oxide, which is more difficult to obtain, sodium carbonate can also be used (see, for example, US 2642347A):

Na₂CO₃ + 4C → → Na₂C₂ + 3CO (5)

The formation of sodium carbide from sodium oxide and carbon already takes place at temperatures of < 1,000⁰C and the formation of sodium oxide from sodium carbonate already begins at 1,000⁰C. The production of sodium carbide from sodium oxide or sodium carbonate and carbon can therefore be carried out at considerably lower temperatures than the production of calcium carbide from calcium oxide and carbon. Sodium carbide has a considerably higher vapour pressure (1 bar at 700⁰C) than the starting products sodium oxide or sodium carbonate. The reactions for the production of sodium carbonate are therefore usually carried out in such a manner that sodium carbide is discharged from the reaction chamber together with carbon monoxide and is then separated from the gas stream by cooling.

Sodium carbide can be reacted similarly to calcium carbide to produce acetylene and sodium hydroxide.

Na₂C₂ + 2 H₂O → 2 NaOH + C₂H₂ (6)

The hydroxides obtained during the liberation of acetylene are important raw materials.

Calcium hydroxide is used in large quantities for the production of building materials and cement. It is also used for the desulphurization of flue gases and in the chemical industry, for example for the production of sodium carbonate by the Solvay process.

Sodium hydroxide is an important product for the chemical industry. Relatively large quantities of sodium hydroxide are also used in other fields than in the chemical industry, such as for example in the production of paper and in the processing of bauxite ores.

The hydroxides remaining after the formation of acetylene can also be reconverted into the corresponding oxides or carbonates and thus recycled into the reaction as starting products. In such recycling, by appropriately purifying and/or discharging a fraction of the oxdies/carbonates the excessive accumulation of by-products in the circulated oxides/hydroxides is avoided.

Acetylene is an important product in industrial organic chemistry. By the addition of hydrogen halides, vinyl halides and polyvinyl halides, such as for example vinyl chloride and polyvinyl chloride, are produced. By the addition of acetic acid, vinyl acetate and polyvinyl acetate are produced, and by the addition of alcohol, vinyl ether and polyvinyl ether. Cyclooctatetraene, acrylic acid, acetic acid, 1,3- and 1 ,4-butanediol, propargyl alcohol, 2- butine-l,4-diol, vinyl ethine, succinic acid, neoprene, chloroprene, vinyl ester, polyvinyl ester, higher alcohols and monochloroethanoic acid are also synthesized from acetylene. Acetylene is less frequently used for producing benzene, butadiene, ethanol, acrylonitrile and polyacrylonitrile, vinyl halides, acrylic acid and acetaldehyde.

Carbides of alkali metals and alkaline earth metals are therefore important compounds for the production of organic compounds. This equally applies to the carbides of aluminium and beryllium, which can be reacted with water or acids to form methane.

The gasification of coal and other carbon-containing gasification materials is also known from the prior art (see for example Ullmann's Encyclopedia of Industrial Chemistry, 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, 10.1002/14356007.al2 169.pub2 "Gas Production", Chapter 4) and is carried out worldwide on an industrial scale in a number of production plants. Carbon gasification refers to a number of processes for converting coal, in which carbon- containing compounds are reacted with oxygen and optionally also with water or steam and at temperatures of from 800⁰C to 2,000°C and pressures of up to 100 bar.

During the gasification of coal a gas mixture is obtained which is referred as the synthesis gas ("syngas"), consists of carbon monoxide and hydrogen and can also contain other components such as carbon dioxide, methane, nitrogen and/or hydrogen sulphide.

The basic reaction for most processes for gasifying carbon-containing compounds is the partial oxidation of carbon with oxygen to give carbon monoxide:

2 C + O₂ → 2 CO ΔH²⁹⁸ - 221 KJ/mol (7)

This reaction produces not only energy-rich carbon monoxide gas but also the energy necessary for the gasification reactions.

As a result of the Boudouard equilibrium, the oxidation of carbon to form carbon dioxide shifts almost completely towards carbon monoxide at temperatures of > 1,000⁰C:

C + CO₂ U 2 CO (8)

Hydrogen gas is also formed as an additional important component of the gasification. Hydrogen is formed from carbon and water at the temperatures prevailing in the gasification process.

C + H₂O i5 H₂ + CO ΔH²⁹⁸ + 131 KJ/mol (9)

In some gasification processes this reaction is systematically induced by the addition of water and steam.

In addition to systematically introduced water the hydrogen bound in the material to be gasified contributes towards the hydrogen fraction of the synthesis gas.

Further basic reactions in the field of coal gasification are the water gas shift reaction

CO + H₂O i* CO₂ + H₂ ΔH²⁹⁸ - 41 KJ/mol ( 10) and methanization

CO + 3 H₂ 15 CH₄ + H₂O ΔH²⁹⁸ -205 KJ/mol (1 1).

Methane is also formed by the direct reaction of carbon with hydrogen

C + 2 H₂ 1; CH₄ ΔH²⁹⁸ - 75 KJ/mol (12). The gasification reaction is usually carried out with oxygen and in some processes air is also used.

Oxygen is obtained by known processes such as the liquefaction of air or pressure swing adsorption. In addition to pure oxygen, gas mixtures with an oxygen content of at least 90%, and preferably 95 - 98%, are used, the remaining components preferably being water, CO₂,

CO, N₂ or inert gases.

The synthesis gas obtained in the gasification of carbon-containing materials can be used for energy production usually after removing undesired secondary components such as hydrogen sulphide. One preferred application is, for example, the use of synthesis gas as a fuel for operating a combination of a gas turbine and a steam turbine which incorporates electricity generation.

The synthesis gas can also be used as a raw material for other chemical syntheses. Suitable processes are, in particular, catalytic conversion into hydrocarbons (the Fischer-Tropsch synthesis) or methanol.

As a result of the shift reaction and the subsequent purging of the carbon dioxide, the ratio of carbon monoxide to hydrogen can be shifted towards pure hydrogen. This hydrogen can be used for chemical syntheses, such as for example for the synthesis of ammonia, or also as an energy source, for example for the operation of gas turbines.

When coal is gasified, its mineral components form slag and ash. Slag and ash can be used commercially as useful materials, such as for example as fillers for cement or for the production of road surfaces. Frequently ash does, however, have to be laboriously disposed of.

A number of processes and apparatuses are known for the gasification of coal (see Ullmann's Encyclopedia of Industrial Chemistry, 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, 10.1002/14356007.al2 169.pub2 "Gas Production" Chapter 4 for a detailed overview).

The main differences between these processes arise from the various types of gasification reactors employed. For the gasification of carbon-containing gasification materials fixed bed reactors, fluidized bed reactors, entrained flow reactors and melting reactors are primarily used.

The pressures and the gasification temperatures vary depending on the process employed and are optimized according to the starting materials used and the required gas quality.

Thus, depending on the process employed, the gasification temperatures are in the range from 800 to higher than 2,000°C.

At lower gasification temperatures tars and aromatic compounds are also obtained which have to be laboriously removed from the gas. At gasification temperatures below l,000°C the percentage of CO₂ in the gas increases as a result of the Boudouard equilibrium. The non- gasifiable components can be discharged in the form of ash at temperatures below the softening point. Otherwise they are discharged in the form of liquid slags.

The higher the gasification temperatures, the higher the demands on the thermal stability of the reactors employed. A number of methods exist for ensuring the stability of the reactors even at high temperatures. Special high temperature-resistant materials are therefore used for constructing the reactors. One frequently used variant is that of cladding the reactor interior with high temperature-resistant materials. In other processes the reaction is carried out in such a manner that a protective slag layer is formed on the inner wall of the reactor. An additional method is to cool the reactor, for example by incorporating corresponding pipelines for cooling with water or by using evaporating water. Frequently a combination of the abovementioned methods is used.

Depending on the design of the gasification reactor, the pressure employed can be in the range from 2 to higher than 100 bar. In some earlier known processes atmospheric pressure is employed.

In fixed bed reactors countercurrent gasification is employed. The lump material to be gasified is fed into the top of the reactor via a lock hopper. Oxygen and, where applicable, steam are introduced at the base of the reactor. The synthesis gas escapes via an opening in the upper region of the reactor and the non-gasifiable components are, depending on the temperatures employed, discharged at the base of the reactor in the form of ash or slag. The temperature in the oxidation zone is, depending on the process employed, between 1,000 and 2,000⁰C, and the pressure ranges are, depending on the process employed, between 20 and 100 bar.

One example of a fixed bed reactor with slag discharge is described in EP 78100 A2.

Gasification in a fluidized bed reactor is carried out by introducing the granular gasification material in the lower region of the reactor via a screw or in the form of a paste mixed with water or oil. The gasification material is vortexed by introducing oxygen and, where applicable, steam and then reacted. In this process additional oxygen and, where applicable, steam, can be introduced in the upper region of the fluidized bed. The reaction gas escapes at the top of the reactor. Solids entrained by the gas are removed in a cyclone and recycled into the reaction.

Non-gasifiable components are discharged in the form of ash at the base of the reactor.

Temperatures of 800 - 1 ,200°C and pressures of from atmospheric pressure to 30 bar are commonly used for the gasification of coal in fluidized bed reactors.

One example of a fluidized reactor is described in DE 4413923. In an entrained flow reactor the powdered gasification material and oxygen are vortexed and reacted, steam possibly being added as they enter the reactor. The reaction gas escapes at the top of the reactor or at a lateral removal point and non-gasifiable components are discharged as slag at the base of the reactor.

Temperatures of 1 ,200 to higher than 2,000°C and pressures of between atmospheric pressure and 100 bar are commonly used for the gasification of coal in entrained flow reactors.

One example of an entrained flow reactor is described in US 4959080.

In a molten bath reactor the material to be gasified and oxygen are fed into a melt. The synthesis gas escapes above the melt and non-gasifiable components are discharged via the melt. The molten bath reactor has so far not been used on an industrial scale.

After the gasification reaction the hot, dust-containing crude gases are freed from dust and cooled. Various types of equipment, such as for example cyclones, scrubbers, electrofilters and candle filters, are used for the removal of dust.

Various means are used for cooling, such as for example heat exchangers, quenching with water or quenching with recycled, cooled synthesis gas.

An important part of cooling is the use of the thermal energy contained in the hot synthesis gas. This is usually obtained by the generation of steam which can be used elsewhere as process heat or for the production of electricity.

Since crude oil and natural gas are likely to become increasingly scarce, while sufficient coal reserves still exist, the gasification of coal and other carbon-containing gasification materials has increasingly gained in importance in recent years.

Gasification processes require complicated equipment and a high input of capital. The economic efficiency of gasification depends not only on the cost of the raw material employed and the cost of the gasification process but also on the value of the products produced by gasification.

In the light of the abovementioned prior art the problem arose of increasing the economic efficiency of coal gasification.

Surprisingly it was found that coal gasification can be combined with the production of carbides, the carbides allowing the production of additional useful products and thereby increasing the economic efficiency of coal gasification.

The present invention therefore relates to a process for gasifying carbon-containing gasification materials by partial oxidation, characterized in that compounds of alkali metals and/or alkaline earth metals and/or compounds of aluminium and/or beryllium are added to the carbon-containing gasification materials with the result that the slags and/or ash obtained by gasification contain quantities of carbides of the respective alkali metals and/or alkaline earth metals and/or aluminium and/or beryllium.

According to the invention the addition of compounds of alkali metals and/or alkaline earth metals and/or aluminium and/or beryllium produces additional useful products, i.e. carbides, which can in turn be reacted to form useful secondary products, thereby increasing the economic efficiency of coal gasification.

Compounds of alkali metals and/or alkaline earth metals and/or aluminium and/or beryllium which can be used are, for example, their oxides, peroxides, hydroxides, carbonates and/or bicarbonates and/or mixtures thereof. In the presence of carbon-containing gasification materials and oxygen they react to form the corresponding carbides. Preferably oxides, peroxides, hydroxides, bicarbonates and/or carbonates of the alkali metals and/or alkaline earth metals are used.

Particularly preferably, one or more compounds from the series comprising calcium oxide, sodium oxide, sodium carbonate and sodium hydroxide are used.

In the following, compounds of alkali metals and/or alkaline earth metals and/or of aluminium and/or beryllium, which react to form the corresponding carbides in the presence of carbon-containing gasification materials and oxygen, are referred to as carbide precursors.

The carbides can in turn be used for the production of acetylene and/or methane by reaction with water and/or an acid.

Carbon-containing gasification materials are understood to be materials with a high content of carbon. Examples of carbon-containing compounds are hard coal, brown coal, peat, anthracite, bituminous coal, low-volatile steam coal, coke, charcoal, petroleum coke, other refinery residues, biomass, industrial waste, household refuse, etc. or mixtures thereof.

According to the invention the carbon-containing gasification materials are partially oxidized with oxygen at temperatures of between 1,000⁰C and 2,500⁰C, while adding one or more carbide precursors. The pressure is between 1 bar and 100 bar.

Reactors already known for the gasification of carbon-containing gasification materials (see above) are fundamentally also suitable for the combination, according to the invention, of gasification and carbide production. Modifications may have to be made in order to cater for the specific features of carbide formation.

Thus, the temperature in the reactor must be selected in such a manner that it is sufficiently high for the formation of carbides. Temperatures of >l,800°C are necessary for the formation of calcium carbide, whereas temperatures of about 1 ,000⁰C are sufficient for the formation of sodium carbide from sodium oxide. The gasification reaction is carried out preferably with oxygen or gas mixtures with an oxygen content of >90%.

The addition of water or steam shall be limited as far as possible in order not to unnecessarily remove heat from the reaction zone.

Depending on the types of carbide concerned, they are discharged in a liquid molten form, or via the gas phase.

Carbides with a high vapour pressure, such as for example sodium carbide, are for example removed from the reactor via the gas stream. The carbide is then removed by separation by cooling the synthesis gas. Cooling is carried out by means of processes known to the skilled man, such as for example via heat exchangers or by quenching with cooled synthesis gas.

Carbides with a low vapour pressure are predominantly discharged in the form of a melt. Methods of treating the melt are known to the skilled man from the production of carbide by the electrothermal process and from metallurgical engineering.

A fraction of the carbides with a low vapour pressure may escape from the reactor in the form of small particles in the gas stream. These particles are removed in separators arranged downstream, together with additional fine dust. Carbide-containing fine dust can be used for acetylene production.

On cooling the gas stream it is important to ensure that possible quenching with water does not take place until after the separation of the carbides contained in the gas chamber. Washing of the synthesis gas with water must also not take place until after the separation of the carbides present in the gas chamber.

The starting products must be dried as far as possible before being fed into the reactor. Preferably the content of moisture is below 5%.

The carbide precursor and the carbon-containing gasification material are preferably finely ground and intimately mixed prior to partial oxidation. The grinding of the starting products can be carried out prior to, during or after mixing.

A finely ground product is understood to be a product in which the average particle diameter of the particles forming the product is smaller than 1 mm. Preferably the maximum diameters of the particles are used for determining the average particle diameter. As is known to the skilled man, these maximum particle diameters can be determined, for example, from photomicrographs of a random sample. The average diameter is understood to be the arithmetic average. In the following the average particle diameter is therefore to be understood to be the arithmetic average of the maximum particle diameters of a random sample. The average particle diameter of at least one of the starting products (the carbide precursor and/or carbon-containing gasification material) is preferably less than 500 μm, particularly preferably less than 100 μm, and very particularly preferably less than 50 μm.

An intimate mixture is understood to mean that a random sample of the mixture in a quantity of 100 g reflects the weight ratio of the starting products with a maximum deviation of +/- 10%, preferably +/- 5% and particularly preferably +/- 1%.

In a preferred embodiment the mixture of the carbide precursors is compacted into larger units. It can for example be agglomerated into pellets or briquettes.

In an additional preferred embodiment the carbide precursor is mixed only with a fraction A of the carbon-containing compound fed into the gasification reaction. The mixture is then fed into the reactor together with another fraction B. These fractions can be introduced jointly, optionally after further mixing, or separately, optionally at different points in the reactor.

It is possible for a different, preferably more carbon-rich, gasification material, to be used for fraction A than for fraction B. Preferably a gasification product with a carbon content of >80%, and particularly preferably >88%, such as for example coke, petroleum coke or anthracite coal is used as fraction A.

In a particularly preferred embodiment the carbide precursor is mixed with the fraction of the carbon-containing compound with a carbon content of >80% in such a manner that the quantities of carbon and alkali metal or alkaline earth metal required for the carbide formation are present in an equivalent, stoichiometric molar ratio, with a maximum deviation of +/-

20%.

The ratio between the components comprising the carbon-containing gasification material, including fractions A and B, oxygen and the carbide precursor must be selected in such a manner that the temperature required for the formation of the carbide is reached.

The crude synthesis gas and other highly volatile components issue from the reactor in the form of a hot gas. Depending on the process employed, the ash fraction is discharged in the form of a molten slag, precipitated ash and/or fine dust in the gas stream.

Depending on its melting or boiling properties, the carbide formed is discharged together with the slag and/or it leaves the reactor in the gas stream in the form of fine dust and/or, in the case of more readily volatile carbides, such as for example sodium carbide, in the form of a gas.

Carbide-containing slag is discharged from the reactor preferably in the form of a melt in crucibles and worked up by processes known to the skilled man from the production of calcium carbide. The calcium carbide discharged in the fine dust is removed by a process known to the skilled man from the field of coal gasification.

Gaseous carbides are condensed by cooling. This can take place for example by quenching the hot gas stream with cooled synthesis gas. The flue ash ensures that sufficient crystallization seeds are present. The condensed carbide is removed by known processes together with the flue ash, although care must be taken to ensure that the carbide does not come into contact with water or moisture, in order to avoid the (premature) production of acetylene.

Using this method carbide-containing slags and/or carbide-containing fine dust are obtained, both of which can also contain fractions of the carbide precursors originally employed. The content of carbide depends on the content of ash of the carbon-containing compound, the proportion of carbide precursors and the reaction conditions such as temperature, pressure and residence time.

In processes optimized for a high carbide content, material with a carbide content of > 80% is obtained. In the case of calcium carbide this corresponds to normal technical quality standards.

The content of carbide can however be lower, such as for example 50-80% or even 10-50%. According to the invention it is important for acetylene and/or methane, and preferably acetylene, to be obtained economically from the carbide-containing slag or the carbide- containing fine dust by reacting it with water and/or acid.

In a preferred embodiment of the process according to the invention the resulting carbide- containing slag and/or ash is reacted in a subsequent step with water and/or an acid. In this process acetylene is preferably obtained.

The process according to the invention is characterized in that the gasification of coal is combined with the synthesis of carbides. The process according to the invention therefore provides the advantage of the improved utilization of the available product and energy resources by the production of additional useful products, such as for example acetylene.

The synthesis gas obtained in the process according to the invention can be used, optionally after further treatment, for known applications, such as for example for the generation of electricity in a combined gas and steam power plant or for the synthesis of additional products such as methanol, ammonia or hydrocarbons by the Fischer-Tropsch process. The process according to the invention can also be combined with a conventional process for producing synthesis gas, such as for example by generating only a portion of the required synthesis gas in the process according to the invention and generating another portion by conventional gasification methods. The synthesis gas streams from the various sources can then be combined and used for a joint application. The invention is explained in more detail hereinbelow with the aid of examples, without, however, being limited thereto. The quantities mentioned in the examples are approximate values which can in individual cases vary by up to 100%, depending on the starting products, reactors and process conditions employed.

Example 1

65 parts of finely divided burnt lime (with an average particle diameter of about 10 μm) and 30 parts of finely ground coke (with an average particle diameter of about 50 μm) are intimately mixed and agglomerated with 5 parts tar to form pellets of a diameter of about 20 mm. 150 kg coal of an average particle size of about 20 mm are introduced per hour into the top of a shaft furnace via an annular lock hopper. Through an additional centrally arranged lock hopper 140 kg/h pellets are introduced in such a manner that a calcium-rich region is formed in the center of the reactor.

In the lower region of the reactor 92 Nm³ of oxygen are introduced centrally and an additional 5 kg/h of steam are injected in the peripheral regions via several annularly distributed jets. The temperature in the centre is about 2,100°C and it falls to about l,600°C towards the edges.

240 Nm³/h of synthesis gas issue from the top of the reactor. 15 kg/h of dust are removed in a cyclone.

100 kg/h of melt are removed at the bottom end of the reactor through a discharge aperture. Per kilogram of discharged product, 280 1 of acetylene are formed with water. The dust removed from the cyclone does not produce any acetylene with water.

Example 2

80 parts of anhydrous, finely divided sodium carbonate (with an average particle diameter of about 10 μm) and 20 parts of ground petroleum coke (with an average particle diameter of 100 μm) are intimately mixed.

A fluidized bed reactor with 3 cyclone separators and recycling of the solids separated in the first cyclone is set in operation with dried brown coal. After an operating temperature of about 1 ,200⁰C is reached in the reactor and of about 900°C in the 1 st cyclone and the recycling line, the introduction of the starting products is adjusted in such a manner that per 100 kg/h of the mixture of sodium carbonate and petroleum coke about 100 kg/h of dried brown coal are introduced into the reactor. 100 m³/h of oxygen are injected in the bottom region of the fluidized bed reactor and another 80 m³/h in the upper third of the fluidized bed. The pressure in the reactor is 3 bar.

After removing particles from the gas issuing from the top of the reactor in the first cyclone it is quenched with recycled synthesis gas cooled to 300°C. In this process particles are formed which are separated in the two subsequent cyclones. The quantities of gas downstream of the separators are 350 Nm³/h.

180 kg/h of dust are removed in the 2nd and 3rd cyclone. 1 kg of dust produces 190 1 of acetylene on adding water.

Example 3

62 parts of finely divided burnt lime (with an average particle diameter of about 10 μm) and 38 parts of finely ground anthracite coal (with an average particle diameter of about 10 μm) are intimately mixed. 120 kg/h of the mixture are gasified together with 150 kg/h of coal and 95 m³/h of oxygen in an entrained flow gasifier at a flame temperature of about 2,400⁰C. The gas issuing from the reactor is quenched with recycled synthesis gas cooled to 300°C and passed through a cyclone.

240 Nm³/h of synthesis gas issue from the top of the reactor. 7 kg/h of dust are removed in a cyclone. 90 kg/h of melt are removed from the bung hole at the base of the reactor.

Per kg of the cooled melt, 220 1 of acetylene are produced with water and per kg of the dust removed from the cyclone, 260 1 of acetylene are produced.

Claims

1. Process for gasifying carbon-containing gasification materials by partial oxidation, characterized in that compounds of alkali metals and/or alkaline earth metals and/or compounds of aluminium and/or beryllium are added to the carbon-containing gasification materials, with the result that the slags and/or ash formed during gasification contain quantities of carbides of the respective alkali metals and/or alkaline earth metals and/or of aluminium and/or beryllium.

2. Process according to claim 1, characterized in that the slags and/or ash obtained are reacted in a further step to form acetylene and/or methane by the addition of water and/or acids.

3. Process according to claim 1 or 2, characterized in that the compounds added are oxides, hydroxides, peroxides, carbonates, bicarbonates or mixtures thereof.

4. Process according to claim 1 or 2, wherein the compounds added consist of calcium oxide.

5. Process according to one of claims 1 to 4, characterized in that the carbon-containing gasification materials and the compounds of the alkali metals and/or alkaline earth metals and/or compounds of aluminium and/or beryllium are intimately mixed in a first step.

6. Process according to one of claims 1 to 4, characterized in that the compounds of the alkali metals and/or alkaline earth metals and/or compounds of aluminium and/or beryllium are intimately mixed in a first step with a fraction A of the carbon-containing gasification material.

7. Process according to one of claims 5 or 6, characterized in that the mixture of alkali metals and/or alkaline earth metals and/or compounds of aluminium and/or beryllium on the one hand and carbon-containing gasification materials on the other is present in a stoichiometric molar ratio with a maximum deviation of +Λ 25% for the formation of the corresponding carbides.

8. Process according to claim 6, characterized in that the carbon-containing gasification material of fraction A has a carbon content of > 80%, and preferably > 88%.

9. Process according to claims 5-8, characterized in that the mixture is compacted into larger units.

10. Process according to one of claims 1 to 9, characterized in that the average particle diameter of at least one of the starting products is smaller than 500 μm, preferably smaller than 100 μm and particularly preferably smaller than 50 μm.

1 1. Process according to one of claims 6-10, characterized in that fraction A of the carbon- containing gasification material which is mixed with the compounds of the alkali metals and/or alkaline earth metals and/or compounds of aluminium and/or beryllium is introduced into the reactor together with an additional fraction B of the carbon-containing gasification material.

12. Process according to one of claims 6-10, characterized in that fraction A of the carbon- containing gasification material which is mixed with the compounds of alkali metals and/or alkaline earth metals and/or compounds of aluminium and/or beryllium and an additional fraction B of the carbon-containing gasification material are introduced into the reactor separately from each other.

13. Process according to one of claims 10 or 11, characterized in that different gasification materials are used in fractions A and B.

14. Process according to one of claims 1 to 12, characterized in that the synthesis gas formed during gasification is mixed with synthesis gas from other sources.

15. Process according to one of claims 1 to 13, characterized in that the synthesis gas is used for the production of electricity and/or for additional chemical reactions.