DE102015217650A1 - Process and apparatus for refining a carbonaceous reactant - Google Patents

Abstract

A method of upgrading a carbonaceous reactant (3) is proposed, comprising the steps of: forming an ionic carbide (5) from the reactant (3) and a metal oxide with an input of energy, using magnesium oxide and / or lithium oxide as the metal oxide becomes; - hydrolysis (6) of the formed carbide (5) to propyne (9) and / or propadiene (9); - dimerization (33) of a first part of the substance (32a) of the propyne (9) and / or the propadiene (9) to benzene (39) to form hydrogen; - Hydrogenation (37) of a second Stoffmengenteils (32b) of the propyne (9) and / or propadiene (9) to propene (38) by means of the hydrogen formed in the dimerization (33); and - alkylating (40) the benzene (39) with the propene (38) to give cumene. The invention further relates to a device for carrying out the method according to the invention.

Description

The invention relates to a method and a device for refining a carbonaceous substance, which is used as a reactant of a chemical reaction. In the process of the present invention, by means of the reactant and by means of a metal oxide, an ionic carbide is formed from which, inter alia, benzene is recovered.

The use of alternative energy sources in the context of the energy transition has led to the possibility of local overcurrent. This is the case because fossil fuel power plants are started or driven only with well-defined load ramps and a minimum load is required for their operation. As a result, it may happen that fossil power plants must be operated, for example, over several hours, although the demand for electricity is low. In other words, there is an excess current for which there is no advantageous use at the time of its generation. Overall, an economic operation of fossil power plants is made more difficult.

One way to use the said excess flow advantageous is the operation of a carbide furnace. By means of a carbide furnace, a carbonaceous material can be reacted with a metal oxide to form a carbide. The reaction typically occurs at high temperatures in the range above 2000 degrees Celsius. Part of the required reaction enthalpy is supplied by means of the carbide furnace. A variety of carbides react spontaneously with the addition of water (hydrolysis) to form a gaseous hydrocarbon. Basically, by means of storage of the gaseous hydrocarbon and by its reconversion an industrially usable energy storage can be provided.

Furthermore, the carbide produced by means of the carbide furnace can be used materially. In this case, carbides are particularly advantageous since their hydrolysis typically only a certain hydrocarbon is formed. For example, in the hydrolysis of calcium carbide (CaC ₂ ), ethyne (C ₂ H ₂ ), which is a commodity chemical and thus constitutes a valuable product, can be industrially processed to a target product. However, preferred organic value products have more than two carbon atoms, so typically a further processing of ethyne (acetylene) is required.

Particularly advantageous is the production of magnesium carbide or magnesium sesquicarbide (Mg ₂ C ₃ ). In the hydrolysis of magnesium carbide, for example, propyne (C ₃ H ₄ ), which is a C ₂ -hydrocarbon unsaturated hydrocarbon, is formed. Furthermore, a possible target product may be, for example, liquefied petroleum gas (LPG), which is a valuable additive for biogas for adjusting its calorific value. Another target product can be propene (C ₃ H ₆ ), which is a high-quality basic chemical for the polymer industry. A disadvantage of the stated target products is that they require hydrogen to produce them, with which the double-unsaturated C ₃ -hydrocarbon formed in the hydrolysis of magnesium carbide is partially or completely saturated. This can become a limiting factor, especially for large-scale industrial plants.

Of particular importance here is the ratio of carbon to hydrogen, that is, the C / H ratio of the hydrocarbon formed. The prior art typically requires further measures to favorably adjust the C / H ratio. This can be achieved, for example - as mentioned above - with the addition of hydrogen. Another possibility is to identify a target product which corresponds to the C / H ratio of the hydrocarbon formed in the hydrolysis.

From the publication WO 1990006897 A1 For example, a process is known in which benzene and hydrogen are produced from magnesium carbide. In the cited document, starting from methane, at a high temperature, for example above 1400 degrees Celsius, formed from the magnesium oxide, the magnesium carbide. In addition, carbon monoxide and hydrogen are produced. Subsequently, the magnesium carbide is hydrolyzed and a mixture of propyne and propadiene recovered. The mixture of propyne and propadiene is also referred to as methylacetylene / propadiene (abbreviated MAPD). It also discloses a process in which the propadiene can be converted to propyne, so that the recovered MAPD can be converted substantially completely to propyne.

Furthermore, the beats WO 1990006897 A1 proposed to dimerize the propyne to benzene (C ₆ H ₆ ). Here, two propyne molecules dimerize to form benzene and hydrogen with ring formation. A disadvantage of the disclosed in the document method is that the benzene is very carcinogenic and toxic and thus its use, for example as a fuel additive, is significantly limited. Another disadvantage of the disclosed method is that methane is used to form the magnesium carbide. This is because methane is a high-quality basic chemical and when used it creates a large volume of other gases, such as carbon monoxide.

The object of the present invention is to improve the above-mentioned process in such a way that a higher-quality target product can be provided without the use of methane.

The object is achieved by a method having the features of independent claim 1 and by an apparatus having the features of independent claim 14. In the dependent claims advantageous refinements and developments of the invention are given.

• – Bildung eines ionischen Carbids aus dem Reaktanten und einem Metalloxid unter einem Eintrag von Energie, wobei als Metalloxid Magnesiumoxid und/oder Lithiumoxid verwendet wird;
• – Hydrolyse des gebildeten Carbids zu Propin und/oder Propadien;
• – Dimerisation eines ersten Stoffmengenteils des Propins und/oder Propadiens zu Benzol unter Bildung von Wasserstoff;
• – Hydrierung eines zweiten Stoffmengenteils des Propins und/oder Propadiens zu Propen mittels des bei der Dimerisation gebildeten Wasserstoffes; und
• – Alkylierung des Benzols mit dem Propen zu Cumol.

The process according to the invention for refining a carbon-containing reactant comprises the following steps:

• - Formation of an ionic carbide from the reactant and a metal oxide with an input of energy, wherein as the metal oxide, magnesium oxide and / or lithium oxide is used;
• Hydrolysis of the formed carbide to propyne and / or propadiene;
• Dimerization of a first portion of propylene and / or propadiene to benzene to form hydrogen;
• - Hydrogenation of a second component of the amount of propyne and / or propadiene to propene by means of the hydrogen formed in the dimerization; and
• - Alkylation of benzene with the propene to cumene.

Here, a carbonaceous reactant is a mixture of substances or a substance comprising at least carbon.

The inventive method is therefore divided into at least five steps.

In a first step, the ionic carbide is formed from the reactant and the metal oxide with the introduction of energy, wherein magnesium oxide and / or lithium oxide is used as the metal oxide.

In a second step, the propyne and / or propadiene is formed by the hydrolysis of the carbide. It may be provided that the carbide is hydrolyzed substantially completely to propyne. This may preferably be made possible by converting the propadiene formed under hydrolysis substantially completely to propyne.

In a third step, the first part of the propylene and / or propadiene is dimerized to benzene with the formation of hydrogen.

In a fourth step of the process according to the invention, the second constituent part of the propyne and / or propadiene is hydrogenated to propene by means of the hydrogen formed during the dimerization. Consequently, for the third and fourth steps, the amount of substance of the propyne formed in the second step is divided into the first and second component parts. In this case, in particular the third and fourth step can be carried out in terms of process technology in parallel.

In a fifth step, the benzene formed in the third step is alkylated to cumene by means of the propene formed in the fourth step.

Thus, according to the present invention, a high quality target product, cumene, is recovered from the carbonaceous reactant to form an ionic carbide. The resulting carbide is hydrolyzed to propyne and / or propadiene as known in the art. Subsequently, a dimerization of the first component of the amount of propyne and / or propadiene to benzene takes place. In the dimerization, hydrogen is released, which is used according to the invention for the hydrogenation of the second component of the propylene and / or propadiene. Advantageously, propene can be recovered from the propyene of the second component portion under hydrogenation by means of the hydrogen formed during the dimerization. It is inventively provided to use the propene for the alkylation of benzene to cumene. The present invention therefore improves upon that in the document WO 1990006897 A1 said method such that the higher quality target product cumene is provided. In addition, a supply of methane is not mandatory.

Cumol is the high-quality target product. In particular, cumene is used as a high-quality fuel additive. Cumene has a very high octane rating of 132 and is non-hygroscopic and compatible with existing fuel or gasoline infrastructure. Advantageously, inferior fuels / fuels having a low octane number can be upgraded by the cumene. Furthermore, cumene can improve and maintain the fluidity of the fuels, especially at lower temperatures. Cumene can be used in particular as an additive for jet fuel. Furthermore, cumene represents a basic chemical for the target products phenol and acetone (Humm's cumene hydroperoxide method).

The present invention therefore provides an efficient process by means of which a high-quality target product, the cumene, can be obtained from a carbon-containing reactant.

For this purpose, it is inventively provided the formed by hydrolysis of propyne and / or propadiene in the first and second Divide Stoffmengenteil. In addition, the propadiene can be completely hydrolyzed to propyne. By dividing the propyne into the first and second component portions, the first component portion can be used to form the benzene, whereas the second component portion can be used to hydrogenate the propene to propene. Subsequently, the formed propene and benzene can be combined, resulting in the alkylene of the benzene with the propene the desired cumene. In other words, according to the invention, the hydrogen formed in the formation of the benzene is used to hydrogenate a triple bond of an alkyne (propyne) selectively to the corresponding alkene (propene).

The present invention therefore makes it possible to refine the carbon-containing reactant, whereby the intermediate of the carbide (metal carbide) prevents selectivity limitations, as are known, for example, from the Fischer-Tropsch process, which is based on gasification and subsequent catalytic conversion of a synthesis gas can be. Since it is a reactive C ₃ body according to the invention, high-quality target products can be synthesized with relatively little effort. The C / H ratio of four to three (4: 3) required for the cumene advantageously corresponds exactly to the product of the hydrolysis (MAPD) of the magnesium carbide. Accordingly, advantageously no further hydrogen is required, which is supplied, or as for example in the WO 1990006897 A1 benzene as the target product, would have to be removed.

According to an advantageous embodiment of the invention, a dehydrogenating and cyclizing catalyst, in particular a transition metal catalyst, is used for the dimerization of the first part of the propylene to benzene.

Mixtures of catalysts can also be used. Particularly preferred are bifunctional catalysts, for example platinum and / or rhenium. Furthermore, a subsequent separation of the benzene from the hydrogen formed by cooling with simultaneous formation of a liquid phase can be achieved by condensation.

Furthermore, it is advantageous to carry out the catalytic dimerization at a temperature above 100 degrees Celsius, in particular at a temperature in the range of 100 degrees Celsius to 700 degrees Celsius. Furthermore, a temperature in the range of 300 degrees Celsius to 600 degrees Celsius, in particular in the range of 450 degrees Celsius to 550 degrees Celsius, may be preferred.

According to an advantageous embodiment of the invention, it is advantageous if the hydrogenation of the second constituent part of the propyne takes place by means of a catalyst, in particular by means of a Lindlar catalyst.

In general, catalysts are advantageous which hydrogenate a triple bond selectively to a double bond, without the resulting double bonds are also hydrogenated. Such selective catalysts are formed for example by Lindlar catalysts.

In a further advantageous embodiment of the invention, the benzene excess from the alkylation is separated from the cumene and recycled to form further cumene.

This advantageously allows the benzene to be added in excess to the alkylation. This is advantageous because in the alkylation of benzene by propene to cumene Mehrfachsubstitutionen can be suppressed or prevented by an excess of the benzene.

It is particularly advantageous to divide the propyne formed under the hydrolysis of the carbide in a molar ratio of essentially two to one (2: 1) into the first and second component parts.

Advantageously, this ensures that there is a substantially exact stoichiometric ratio in the formation of the benzene and the propene. In other words, to form a benzene molecule (C ₆ H ₆ ) two propyne molecules (C ₃ H ₄ ) are required, whereby one hydrogen molecule (H ₂ ) is split off. For the formation of a propene molecule (C ₃ H ₆ ), a propyne molecule and a hydrogen molecule (H ₂ ) are required, the hydrogen molecule being provided by the hydrogen molecule cleaved in the formation of benzene.

If a first reactor for forming the benzene and a second reactor for forming the propene have different yields, then a molar ratio that is different from two to one may be advantageous. In other words, the molar ratio can be adjusted to compensate for the different yields of the first and second reactors. Furthermore, the molar ratio may be at least ten percent different from the said ideal molar ratio (2: 1).

Preferably, the alkylation of benzene with propene to cumene by means of a Friedel-Crafts alkylation.

According to a particularly advantageous embodiment of the invention, an arc of a Arc furnace used to introduce the energy in the formation of the ionic carbide.

As a result, the metal oxide, that is to say the magnesium oxide and / or lithium oxide, reacts with the carbon-containing reactant to form the carbide, ie to the magnesium carbide and / or lithium carbide. This carbon monoxide is also formed. This is advantageous because, compared to the prior art, no methane is required for the formation of the carbide, in particular for the formation of the magnesium carbide.

Consequently, the electrical energy of the arc furnace is used to form the carbide. In this case, the entry of the energy is advantageously carried out by the arc of the arc furnace. The formation of the carbide can thus take place if, for example, a threshold value for an oversupply of electrical energy (excess current) is exceeded within a power network provided for the supply of the arc furnace. In general, the carbide furnace can also be supplied with electrical energy if there is an oversupply of electrical energy within the power grid, that is to say the threshold for the oversupply is exceeded.

As a result, the excess flow can be used inexpensively to form the carbide and thus to refine the carbon-containing reactant. According to the present invention, the carbonaceous reactant is refined into the beneficial target product cumene.

The oversupply of electrical energy in the power grid is usually characterized by a fall in the price of electricity on a power exchange, so that the exceeding of said threshold value typically correlates with a falling below a certain threshold value of the electricity price. Another parameter for determining the threshold value of oversupply lies in the measurement of the grid frequency of the power grid. With increasing electrical energy in the power grid also increases the grid frequency, so that the grid frequency can be used as a measure of the oversupply of electrical energy in the power grid. This is particularly advantageous when it comes to self-contained, possibly localized power grids whose electrical energy is not traded on a power exchange. There are other possibilities to determine an oversupply of electrical energy within a power grid, for example by means of an increased grid voltage, in particular in a DC power grid.

It is particularly preferred to use as coal-containing reactants a coal, a lignite and / or a biomass.

Advantageously, electric arc furnaces can be used flexibly, so that, if appropriate, after a corresponding pretreatment, inferior carbonaceous reactants, such as, for example, brown coal and / or biomass, can advantageously also be used. Furthermore, electric arc furnaces can absorb a large amount of excess current or excess electrical energy and can also be operated dynamically.

According to a further advantageous embodiment of the invention, a third substance component of the propyne is hydrogenated to propane by means of the hydrogen formed during the dimerization or by means of an additional hydrogen.

Advantageously, propane is a preferred target product. In particular, propane can be mixed with biogas in order to adjust or increase its calorific value (Wobbe index). The additional hydrogen can be provided by means of an electrolyzer.

In a further advantageous embodiment of the invention, the metal hydroxide formed by the hydrolysis of the carbide is dried to metal oxide.

Advantageously, thereby the metal oxide can be used again to form carbide under the input of energy. In other words, there is an advantageous cycle in which the metal oxide and metal hydroxide occur only as intermediates. Essentially, therefore, only the carbonaceous reactant and the enlisted energy must be supplied to said cycle for the formation of cumene.

• – einen Ofen zur Bildung eines ionischen Carbids aus einem kohlenstoffhaltigen Reaktanten und einem Metalloxid unter einem Eintrag von Energie, wobei das Metalloxid Magnesiumoxid und/oder Lithiumoxid ist;
• – einen Entwickler zur Hydrolyse des gebildeten Carbids zu Propin und/oder Propadien;
• – einen ersten Reaktor zur Dimerisation eines ersten Stoffmengenteils des Propins und/oder Propadiens zu Benzol unter Bildung von Wasserstoff;
• – einen zweiten Reaktor zur Hydrierung eines zweiten Stoffmengenteils des Propins und/oder Propadiens zu Propen mittels des bei der Dimerisation gebildeten Wasserstoffes; und
• – einen dritten Reaktor zur Alkylierung des Benzols mit dem Propen zu Cumol.

The device according to the invention for carrying out the method according to one of the preceding claims comprises

• An oven for forming an ionic carbide from a carbon-containing reactant and a metal oxide with an input of energy, wherein the metal oxide is magnesium oxide and / or lithium oxide;
• A developer for hydrolyzing the formed carbide to propyne and / or propadiene;
• A first reactor for dimerization of a first portion of the propylene and / or propadiene to benzene to form hydrogen;
• A second reactor for the hydrogenation of a second component of the propylene and / or propadiene to propene by means of the hydrogen formed during the dimerization; and
• A third reactor for the alkylation of the benzene with the propene to cumene.

The above-mentioned method according to the invention results in similar and equivalent advantages of the device according to the invention.

Furthermore, it is particularly preferred if the furnace is designed as an electric arc furnace.

Further advantages, features and details of the invention will become apparent from the embodiments described below and with reference to the drawings. Shown schematically:

1 a first section of an exemplary flow diagram of the inventive method in which a formed magnesium hydroxide is dried by means of a calcination furnace;

2 a second section of an exemplary flow diagram of the method according to the invention, in addition to 1 the magnesium hydroxide is used in a gas scrub to separate carbon dioxide; and

3 a third section of an exemplary flow diagram of the method according to the invention, in which propyne for the production of cumene is divided into a first and second Stoffmengenteil.

Similar, equivalent or equivalent elements may be provided with the same reference numerals in the figures. In particular, steps of the method and devices provided for carrying out the steps may be provided with the same reference numerals.

1 shows the first part 1 of the exemplary flow diagram of the method according to the invention, in which a magnesium hydroxide formed by means of a calcination furnace 15 is dried. This is done using a carbide furnace 2 initially generated propyne and / or propadiene (abbreviated MAPD). The carbide furnace 2 is in particular designed as an electric arc furnace and comprises magnesium oxide and a carbon-containing reactant. The carbide furnace 2 may also include lithium oxide or a mixture of magnesium oxide and lithium oxide. In the following, the method is explained using the example of magnesium oxide, wherein the process described is transferable to the lithium oxide or to the mixture of magnesium oxide and lithium oxide without further difficulties.

By means of the carbide furnace 2 a conversion of magnesium oxide to magnesium (sesqui) carbide (carbide) takes place. The carbonaceous reactant required for the conversion is via a feed line 3 the carbide furnace 2 fed. Under an input of energy, magnesium carbide (carbide) is formed from the magnesium oxide and the carbon-containing reactant, with the addition of a gas mixture comprising at least carbon monoxide and carbon dioxide. The said gas mixture may be the carbide furnace 2 via a redirect 4 leave.

About a redirect 5 the carbide becomes a developer 6 directed. However, an intermediate storage of magnesium carbide is conceivable, since this forms a solid at room temperature. When storing the magnesium carbide, it is necessary to ensure that it does not come into contact with water.

In the developer 6 the magnesium carbide is mixed with water (hydrolysis 6 ), wherein the magnesium carbide is hydrolyzed to form propyne and / or propadiene (MAPD) and magnesium hydroxide. The propyne and / or propadiene may have a drainage 9 be continued. Depending on the design of the developer 6 In this case, a sludge of magnesium hydroxide or a powder of magnesium hydroxide is formed. It is advantageous if the developer 6 is designed as a wet developer. In this case, water is in excess to the hydrolysis 6 and used as a coolant. Furthermore, the developer 6 be designed as a dry developer. In a slightly superstoichiometric drying here essentially dry magnesium hydroxide is obtained. However, for the dry developer compared to the wet developer, additional components are required to achieve the hydrolysis 6 dissipate the resulting waste heat. In addition, dry developers are significantly more expensive than wet developers.

In 1 is the developer 6 formed as a wet developer, so that the formed magnesium hydroxide is present as a sludge. The muddy magnesium hydroxide is passed over 10 transported and a first separator 13 , which allows a solid / liquid separation, fed. The first separator 13 can be designed as a filter press. The case released water, in which still a small portion of the magnesium hydroxide may be dissolved, may advantageously for hydrolysis 6 be used. This is the return line 7 provided that the water released to the developer 6 recirculates. One for the hydrolysis 6 Required additional water is via a supply line 8th the developer 6 fed. If a dry developer is used instead of a wet developer, then the first separator is 13 not mandatory.

The separated magnesium hydroxide, which may still have some residual moisture, is passed on 14 to the calcination furnace 15 guided. The calciner 15 is heated. Using the carbon monoxide-containing and carbon dioxide-containing gas mixture from the carbide furnace 2 a particularly advantageous heating is possible. The gas mixture of the carbide furnace 2 this is the calciner 15 about the diversion 4 fed. An oxygen required for combustion is supplied via a supply line 16 the calciner 15 fed. For this purpose, air or atmospheric oxygen can be used. Furthermore, the calciner 15 be designed as a rotary kiln. By means of calciner 15 The previously separated magnesium hydroxide is calcined to form magnesium oxide, which via a return line 17 to the carbide furnace 2 is returned. Consequently, magnesium carbide, and thus propyne and / or propadiene, can be re-formed from the recycled magnesium oxide in a new cycle.

An exhaust gas from the calciner 15 which comprises, for example, water, carbon dioxide and optionally constituents of air, is discharged via a discharge 21 to the environment of the calciner 15 issued.

2 shows a second section 102 , which is essentially an embodiment of the in 1 illustrated flowchart illustrates. This includes 2 at least the in 1 illustrated elements.

According to 2 will be the developer 6 produced sludge of magnesium hydroxide of a gas scrubber 11 by means of forwarding 10 fed. By means of gas scrubbing 11 The carbon dioxide from the exhaust gas of the calciner 15 separated. This is advantageous because a magnesium carbonate formed thereby is less soluble than magnesium hydroxide, so that separation and drying by the first separation device 13 is relieved. The magnesium carbonate becomes the first separator 13 by means of forwarding 12 fed.

In the in 2 illustrated embodiment, the exhaust gas of the calcination furnace 15 by means of a forwarding 18 to a heat exchanger 19 , which is designed as a cooling device, passed. That by means of the heat exchanger 19 cooled exhaust gas is then passed through a supply line 20 supplied to the gas scrubber. The heat exchanger 19 supports gas scrubbing 11 advantageously in their function. A residual gas scrubbing gas 11 will be over the drain 21 delivered to the environment.

Furthermore, by means of the dried magnesium hydroxide, it would be possible to upgrade another exhaust gas, for example the exhaust gas produced during the pyrolysis of lignite or biomass. For this purpose, by means of the magnesium hydroxide carbon dioxide from said additional exhaust gas (not in 2 shown) separated.

In 3 is a third cutout 103 an exemplary flow diagram of the method according to the invention, in which the propyne for the production of cumene in a first and second Stoffmengenteil 32a . 32b is split.

The over the forwarding 9 (see also 1 and or 2 ) Continued mixture of propyne and / or propadiene (MAPD) is first, essentially completely, by means of an isomerization reaction 31 converted to propyne. This can be done for example by means of in the WO 1990006897 A1 disclosed method. Subsequently, the Propin is over a forwarding 32 continued and in a first and second molar flow 32a . 32b divided up. Here, the first substance component corresponds 32a the first molar flow 32a and the second component part 32b the second molar flow 32b so that they are respectively identified by the same reference numeral. In this case, a ratio of about two to one (2: 1) is particularly preferred. In other words, the first Stoffmengenteil 32a about twice as much propyne as the second component 32b on.

By means of a first reactor 33 a dimerization occurs 33 the first Stoffmengenteils 32a of the propyne to benzene. Here, hydrogen is formed, so that after dimerization 33 a mixture of benzene and hydrogen is present. The said mixture is via a forwarding 34 continued and a second separator 35 fed. The second separator 35 is intended to separate the mixture into its components benzene and hydrogen. The benzene is going through a redirect 39 continued. The hydrogen is transmitted by means of a forwarding 36 a second reactor 37 , which is designed as hydrogenation, fed. By means of the second reactor 37 becomes the second component of the substance 32b Propylene is hydrogenated using the hydrogen released by the formation of benzene. There is preferably a selective hydrogenation 37 of propyne to propene. Particular preference is given to using a Lindlar catalyst for this purpose. It is also conceivable for the isomerization reaction 31 to renounce and to produce at least a part of the Prop also from Propadien (in 3 not shown).

Assign the first and second reactor 33 . 37 different yields, so may a molar ratio, which is different from two to one, be beneficial. In other words, the molar ratio can be adjusted so that the different yields of the first and second reactors 33 . 37 be compensated.

The Propen is about a redirect 38 a third reactor 40 who as Alkylierungsvorrichtung is formed fed. The benzene is passing through 39 the third reactor 40 fed. By means of the third reactor 40 a cumene synthesis is carried out, for example by means of a Friedel-Crafts alkylation. A Friedel-Crafts alkylation is typically catalyzed by a Lewis acid, such as aluminum chloride, in which case the propene is activated by a Brönsted acid by converting it into a carbenium ion. A disadvantage of the Friedel-Crafts alkylation is that it has multiple substitutions. To prevent multiple substitutions, it is advantageous to alkylation 40 with an excess of benzene.

Overall, the alkylation results 40 a mixture of the benzene and the target product cumene. Typically, two methods for cumene synthesis are used industrially.

According to a first method, the cumene synthesis takes place within a gas phase by means of phosphoric acid and a zeolite catalyst in a temperature range from 250 degrees Celsius to 350 degrees Celsius. Typically, said gas phase has a pressure above 40 megapascals (400 bar).

According to a second method, the cumene synthesis takes place in a liquid phase of aluminum chloride and sulfuric acid or hydrofluoric acid.

After the synthesis of cumene, the mixture of benzene and cumene is passed on 41 in a third separation device 42 directed. The third separator 42 is intended for the separation of cumene and benzene. The separated benzene is in the third reactor 40 by means of a return line 43 for further alkylation 40 recycled.

It is particularly advantageous here to separate the benzene by distillation in the form of a rectification (countercurrent distillation). For rectification, a waste heat from further steps of the process, in particular from the carbide furnace 2 and / or from the developer 6 , be used. The target product cumene separated from the benzene finally passes through the outlet 44 won.

Of particular advantage is the carbide furnace 2 be supplied with electricity when the price of electricity is below a certain threshold and / or a threshold for excess supply of electrical energy in the grid is exceeded. In particular, the specific investment costs, ie the costs per kilowatt hour, for the carbide furnace 2 comparatively low.

Although the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples, or other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• WO 1990006897 A1 [0007, 0008, 0019, 0023, 0066]

Claims (15)

Process for refining a carbon-containing reactant ( 3 ), comprising the following steps: formation of an ionic carbide ( 5 ) from the reactant ( 3 ) and a metal oxide with an input of energy, wherein magnesium oxide and / or lithium oxide is used as metal oxide; Hydrolysis ( 6 ) of the formed carbide ( 5 ) to propyne ( 9 ) and / or propadiene ( 9 ); - Dimerization ( 33 ) of a first substance component ( 32a ) of the propyne ( 9 ) and / or propadiene ( 9 ) to benzene ( 39 ) with formation of hydrogen; - hydrogenation ( 37 ) a second component of the substance ( 32b ) of the propyne ( 9 ) and / or propadiene ( 9 ) to propene ( 38 ) by means of dimerization ( 33 ) formed hydrogen; and - alkylation ( 40 ) of benzene ( 39 ) with the propene ( 38 ) to cumol. Process according to claim 1, wherein the said under hydrolysis ( 6 ) formed propadiene ( 9 ) substantially completely to propyne ( 9 ) is converted. Process according to Claim 1 or 2, in which a dehydrogenating and cyclizing catalyst, in particular a transition metal catalyst, for dimerization ( 33 ) of the first component ( 32a ) of the propyne ( 9 ) to benzene ( 39 ) is used. Process according to Claim 3, in which the catalytic dimerization ( 33 ) at a temperature above 100 degrees Celsius, in particular at a temperature in the range of 100 degrees Celsius to 700 degrees Celsius, takes place. Process according to one of the preceding claims, in which the hydrogenation ( 37 ) of the second component ( 32b ) of the propyne ( 9 ) by means of a catalyst, in particular by means of a Lindlar catalyst. A process according to any one of the preceding claims wherein the alkylation ( 40 ) excess benzene ( 43 ) is separated from the cumene and recycled to form additional cumene. Process according to any one of the preceding claims, in which the said under hydrolysis ( 6 ) of carbide ( 5 ) formed propyne ( 9 ) in a molar ratio of substantially two to one in the first and second component parts ( 32a . 32b ) is divided. Process according to one of the preceding claims, in which the alkylation ( 40 ) of benzene ( 39 ) with propene ( 38 ) to cumene by means of a Friedel-Crafts alkylation. Method according to one of the preceding claims, in which an arc of an arc furnace ( 2 ) for introducing the energy in the formation of the ionic carbide ( 5 ) is used. Method according to one of the preceding claims, in which the electric arc furnace ( 2 ) to form the carbide ( 5 ) is operated if a threshold for oversupply of electrical energy in a power grid for operating the arc furnace is exceeded. Process according to one of the preceding claims, in which as the carbon-containing reactant ( 3 ) a coal, a lignite and / or a biomass is / will be used. Process according to any one of the preceding claims, in which a third component of the propyne ( 9 ) to propane by means of dimerization ( 33 ) hydrogenated or by means of an additional hydrogen is hydrogenated. Process according to any one of the preceding claims, in which one under hydrolysis ( 6 ) of carbide ( 5 ) formed metal hydroxide ( 10 ) to metal oxide ( 17 ) is dried. Apparatus for carrying out the method according to one of the preceding claims, comprising - a furnace ( 2 ) to form an ionic carbide ( 5 ) from a carbon-containing reactant ( 3 and a metal oxide with an input of energy, wherein the metal oxide is magnesium oxide and / or lithium oxide; - a developer ( 6 ) for hydrolysis of the formed carbide ( 5 ) to propyne ( 9 ) and / or propadiene ( 9 ); A first reactor ( 33 ) for the dimerization of a first component of the substance ( 32a ) of the propyne ( 9 ) and / or propadiene ( 9 ) to benzene ( 39 ) with formation of hydrogen; A second reactor ( 37 ) for the hydrogenation of a second component of the substance ( 32b ) of the propyne ( 9 ) and / or propadiene ( 9 ) to propene ( 38 ) by means of the hydrogen formed in the dimerization; and a third reactor ( 40 ) for the alkylation of benzene ( 39 ) with the propene ( 38 ) to cumol. Device according to claim 14, characterized in that the furnace ( 2 ) is designed as an electric arc furnace.

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