DE1144260B - Process for the production of acetylene by thermal cracking of liquid hydrocarbons - Google Patents

Description

It is well known that hydrocarbons can be converted into unsaturated gaseous products with the addition of energy, especially acetylene, split. On the other hand, the cleavage products formed must be at high temperature Immediately again largely energy is withdrawn to further decay and other side reactions to prevent.

The well-known processes for the splitting of hydrocarbons, in particular to acetylene, therefore differ not only in the choice of the hydrocarbons to be cleaved but also in particular in that the type of energy supply to the feedstock and the energy withdrawal when quenching the Product gases.

For the splitting of liquid hydrocarbons, the supply of the required energy can, for example be done by the arc or by the fact that vaporizable raw materials in the hot combustion products of the same or another vaporizable or gaseous fuel are introduced. Also are processes with a regenerative Heat supply to liquid hydrocarbons known. Other cleavage processes produce the cleavage required heat through partial combustion of some of the liquid hydrocarbons with air or oxygen in the liquid hydrocarbons to be cleaved themselves. These are in excess Existing hydrocarbons are split by the developed heat of combustion.

The rapid quenching of the hot reaction products which necessarily follows each cleavage can be done, for example, by injecting water into the outflowing product gas. In this way, however, a very large part of the total energy used in the reaction is lost. In order to make the sensible heat of the product gas usable for preheating the input material, It has also been proposed to use the hydrocarbons to be split as a deterrent instead of water, with these in the product gas be atomized or, conversely, the product gas directly through the liquid to be split Hydrocarbons can be passed through.

This gives rise to further differences in the implementation of thermal cleavage processes by partial Combustion of liquid hydrocarbons.

It is known to have a flame beneath the surface of liquid hydrocarbons, especially mineral oils, to entertain. For this purpose, the liquid hydrocarbons to be split are mixed with oxygen inside a diving bell serving as a flame chamber zer-method for production

of acetylene by thermal cracking

of liquid hydrocarbons

Applicant:

Aniline & Soda Factory in Baden

Corporation,

Ludwigshafen / Rhine

Dr. Helmut Nonnenmacher, Ludwigshafen / Rhine,

Dr. Otto Jenkner, Mannheim,

and Dr. Richard Sinn, Ludwigshafen / Rhine,

have been named as inventors

dusts and ignites. The heat reflection from the brick-lined bell walls determines the flame stability. In the course of the partial combustion, excess amounts are supplied to the burner nozzle Split hydrocarbons. The resulting reaction gases appear at the lower edge of the bell enter the liquid hydrocarbon phase and are thereby rapidly cooled. The one in the split Resulting liquid products as well as the soot mix with the submitted liquid hydrocarbons to the oil sump, the viscosity of which is constantly increasing. In the steady state there is therefore an oil sump fed from the quenching chamber to the burner nozzle for combustion and fission. The replacement of consumed hydrocarbons is carried out by adding liquid feedstock either before the Burner nozzle or directly into the oil sump of the quench tank.

Another method for cracking liquid hydrocarbons works without a diving bell. One Immersion flame is maintained directly in the liquid hydrocarbons to be split. In a Implementation form, only the oxygen is led under the surface of the liquid and as Let the flame react. The one here in the interface between the flame and the surrounding area The heat of reaction released by the oil phase splits the hydrocarbons. The oil sump to cover of the used oil the liquid to be split

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of protective measures. So the large reaction space filled with the liquid hydrocarbons, in which the immersion flame is burning, placed in a correspondingly large concrete chamber, 5 since continuous self-ignition of the flame is not guaranteed in a liquid system. Of the Throughput capacity itself is determined by the violence of the gas evolution, which the liquid out of the reaction vessel up, set a limit. These

Hydrocarbons are added, takes over
Quenching the reaction products. To control the soot content of the oil sump, for example
continuously or periodically part of the suspension
of the finely divided carbon in the liquid hydrocarbons. After separation from the soot, the liquid hydrocarbons are returned to the reaction vessel.
It can also be done in such a way that one
Part of the soot-containing hydrocarbons from the io disadvantages burden any increase in the scale, subtracts the reaction space and returns part of it to the reaction space in which the process is to be carried out, so that the combustion of fission oils in the combustion chamber takes place at the entry and in the flame space Due to their ash content, the mern is in the long run surrounded by oxygen. The other, much less total wall damage, is the well-known part of the soot-containing hydrocarbons, which the 15 process, which the required fissure energies is 3 to 50 times the amount that is supplied by the burners in the form of hot burner gases, the total acid supplied to the combustion chamber - If gaseous or easily vaporizable carbon could be burned completely, hydrogen is used. Because of the technical partial combustion in the oxygen itself atomized. Difficulties associated with repatriation

It has also been proposed that in the event of a crude oil cracking for combustion in

mix fission of liquid hydrocarbons these combustion chambers oppose, become fission

with insufficient quantities of acid for combustion in the reactor, which is located downstream of the combustion chamber

substance is to be finely atomized in the free reaction space and only gaseous or vaporized hydrocarbons

to let react after the ignition. This fuel is used for light to medium oil cuts,

driving makes use of a special form of the 25 The exclusion of crude oils for splitting is a

immediate deterrence of the incineration disadvantage of these procedures.

and fission gases existing reaction mixture with It has now been a process for the preparation of the same hydrocarbons that are used to break down acetylene through the thermal breakdown of liquid coals. It consists in the fact that from the start, hydrocarbons, especially hydrocarbons before the incineration and cleavage, mix such an amount containing an excess of non-evaporable constituents of liquid hydrocarbons with the th, for example crude oils, found that this Oxygen is atomized that also avoids simultaneous disadvantages and compared to the known Quenching of the reaction gases can take place. Process delivers a product gas that as a result of its In stationary operation, the atomizer nozzle with a lower olefin content then becomes easier to separate with the products of the acetylene from the product gas in the reaction vessel. Even collecting sump with admixture of in can the low-olefin residual gas, since there is no further base oil to cover the amount of hydrocarbons consumed.

All of the processes mentioned for the thermal cleavage of liquid hydrocarbons by partial decomposition
combustion has in common that in its implementation
the actual liquid raw material to be split and the
liquid products of the reaction not on their own,
but inevitably mixed with each other in the process. The acetylene of the product - a part of the gases formed during the cleavage - falls as a result of a considerable proportion of recycled soot-containing liquid products with additional oxygen, especially ethylene, and is diluted in the jet Hch for processing. The excessive amount of hot reaction products formed in the process stems from subsequent lent initially one or more beams of the cracking reactions that result in the quenching process at 50 or higher hydrocarbons and then lowering temperatures than that of the original quenching of the reaction mixture several borrowed cleavage of hydrocarbons of the radiation from circulating soot-containing liquid deterrent can occur. sigen fission products are supplied, the

The higher energy utilization due to jets introduced from the side such a dynamic pressure

addition of sensible heat into chemical energy, that it

Licher olefinic cleavage products, however, the products penetrate and are largely permeable.

due to the increased content of olefins are mixed more, and the amount to be cleaved

The load on the separation of acetylene from the product gas, hydrocarbons, is measured in such a way that 1 Nm ³

opposite to. In addition, with the acetylene oxygen 3.0 to 1.0 kg, preferably 2.5 to 1.5 kg,

separation of a still substantially enriched in olefins correspond to the hydrocarbons to be split,

chertes lean gas accumulates, which is a further separation and the amount of circulated and

is supplied by the olefins. use to quench the reaction mixture

A process for the cleavage of liquid hydrocarbons and cleavage products for a lowering of the temperature substances, which delivers an acetylene-rich, but low-olefin product of the reaction mixture to below 500 ° C, would therefore have an advantage over 65 sufficient,
the known procedures. Experience has shown that for rapid transit

Another disadvantage, for example, the immersion mixing of rays by crossing rays

flame cracking, consists in the increased effort product of the ratio of the back pressure of the lateral

Separation is subjected to the same in a simple manner, for. B. by flameless fission with oxygen, in Syngas are transferred.

The inventive method consists in that the liquid hydrocarbons to be split, in particular crude oils and their liquid fission products, are used separately in the process by in a common free space by means of a burner

union beam to dynamic pressure of the reaction products, both measured at the point of penetration, and the corresponding ratio of the beam diameter within the range of 0.01 to 3, preferably from 0.02 to 1.

To completely remove the liquid cleavage products that result from the cleavage and boil above 85 ° C to react with oxygen, they are expediently in an amount of 30 to 150% of the cleavage Hydrocarbons returned to the burner.

The jet of hot reaction products formed points before mixing with the products to be cleaved Hydrocarbons a temperature of 1200 to 2800 ° C, preferably from 1800 to 2200 ° C. After mixing with the hydrocarbons to be cleaved, a temperature prevails from 800 to 1600 ° C, preferably from 1000 to 1400 ° C. This temperature is quenched with the circulating liquid cleavage products lowered to about 100 to 500 ° C.

The inventive method can at normal or elevated pressure, for example 5 to 20 at.

The method is not limited to pure oxygen. You can also add diluents to the oxygen, such as nitrogen, carbon dioxide and especially water vapor.

It is also possible to add carbonic acid or steam to the reaction space jointly or separately with the hydrocarbons to be fissioned and / or with the fission products used for deterrence feed, the mixing with the reaction products or with the reaction mixture takes place by crossing rays.

The principle of this cleavage process was first carried out on a laboratory scale on model substances, about the stable conditions of flame formation under the conditions of the reaction according to the invention to investigate. As a model substance of the liquid hydrocarbon to be split was Light petrol, used as a model substance for the liquid fission products benzene.

The procedure was that in a cold oxygen jet, the deficit of the surrounding methane flowing out of a burner at a speed of between 50 and 125 m / sec into a free space was fed to two directly opposite nozzles. The ratio Nm ³ oxygen per kilogram of gasoline injected was between 0.5 and 0.8, the exit speed of the gasoline jets between 5 and 25 m / sec. The product gases were quenched at 1000 to 1300 ° C by benzene vapor just above the visible reaction zone to about 300 ° C. The quenched product gas was free of oxygen even after the oxygen exceeded 2.5 times the amount required for complete combustion of the methane.

The security that distinguishes the process from those in which oxygen accumulates in the Product gas can occur, can be recognized by the extreme case that the oxygen without methane in flows into the reaction space. Even under this condition, the cold oxygen is fully capable of in to react with the injected hydrocarbons in a short flame. To keep the flames When performing this test, a small lure flame burned in the direction of the mixing point of Oxygen and gasoline vapor. The product of the dynamic pressure ratio of the gasoline vapor jet to the oxygen jet and the corresponding ratio of the beam diameter was at the mixing point between 0.004 and 0.4. The product gas also remains free of oxygen than, optionally, the Benzene or gasoline vapor supply into the reaction vessel has been interrupted.

For example, the product gas of a quenching with benzene assigns a percentage molar ratio of acetylene to acetylene + ethylene of 69.5 and a volume ratio of acetylene to ethylene of 2.29 or a volume ratio of acetylenes ^{for a value of 0.8 Nm 3 of oxygen per kilogram of gasoline injected} Ethylene + higher G ₂ H _2n olefins of 1.65. A deterrent with petrol instead of benzene gives the comparative values 54.0, 1.18 and 0.9. A similar shift to a more olefin-rich gas composition occurred with quenching with benzene-gasoline blends.

A device suitable for carrying out the method according to the invention is shown in FIG. 1 for example and shown schematically. A burner 1, the mouth of which protrudes into a free reaction chamber 2 from below, are at 3 soot-containing liquid products resulting from the cleavage are supplied. At 4, the required is supplied Oxygen. After the mixture has been ignited by one or more lure flames 5, the Jet of the hot reaction products laterally over the nozzle ring 6 one or more liquid jets of the injected liquid hydrocarbon to be split.

After a short reaction time, the jet of reaction products is used to quench the hot product gases by one or more jets of soot-containing liquid fission products that are circulated emerge from the nozzle ring 7, largely torn. The inner walls of the reaction chamber 2 are flushed from above through a hollow cone nozzle 8 with liquid fission products.

The cooled product gases leave the reaction space at 9 together with liquid products and flow via the pipeline 10 to a washing and cooling column 11, over to the top of the column line 12 condensate gasoline is pumped for evaporative cooling. In some cases it is expediently, the cooled product gases and vapors separately from the liquid products of the Feed column. In this case, as illustrated in FIG. 2, the liquid products overflow the pipeline 10, which is provided with a dip tube, into the column sump 14, and the gas and vaporous products leave the reaction space in a pipeline above the quenching nozzles 7 22, which opens into the container 14 above the sump level. Via a waste heat boiler 13, which is connected to the column bottom 14, additional heat can be withdrawn from the column. The operation of the column is carried out in such a way that the circulating via lines 15, 16, 17, 18, 9, 10 and the column bottom guided by the container 14 remains constant.

The cooled product gases, most of which have been freed from soot, are used for further work-up in downstream parts 19 of the apparatus at 20 from the column.

To remove ash, sump oil is drawn off to the outside via line 21.

example

17 kg of soot-containing liquid cleavage products per hour from the container 14 and at the same time 15 Nm ^{3 of} oxygen are fed to a burner 1 for intimate mixing. The mixture is ignited when it exits the reaction chamber 2 by means of attracting flames 5 which are fed with heating gas and oxygen. 25 kg of crude oil per hour are injected into the jet of the hot reaction products formed via the nozzles 6 for splitting. After a cleavage time of about 0.003 seconds, the reaction products are quenched to 250 ° C. by circulating soot-containing liquid cleavage products by feeding about 1000 kg of bottom products from 14 via pipes 15 and 17 to the quench nozzles 7 per hour. To avoid soot deposits in the reaction space, the vessel walls are rinsed by 100 kg of sump products per hour, which are atomized by means of a hollow cone nozzle 8. The quenched gases and vapors reach column 11 together with liquid products via pipeline 10. 1 kg of bottom products per hour are withdrawn from 14 via line 21 to the outside.

When 25 kg of crude oil are ^{broken down, 43 Nm 3 of} fission gases are produced, which contain 11.0 percent by volume of acetylene and 4.5 percent by volume of olefinic hydrocarbons. The rest of the gas consists mainly of carbon monoxide and hydrogen.

Claims (4)

PATENT CLAIMS: 1. A process for the production of acetylene by thermal cleavage of liquid hydrocarbons, especially crude oils, with insufficient amounts of oxygen for complete combustion and quenching of the reaction products with oil, characterized in that a part of the resulting in the cleavage by means of a burner in a common free space and recycled soot-containing liquid products are reacted with oxygen in a manner known per se and the jet of hot reaction products formed is initially one or more jets of the hydrocarbons to be split and then one or more jets of circulating soot-containing liquids to quench the reaction mixture Fission products are fed, the laterally introduced jets have such a dynamic pressure that they penetrate into the jet of the reaction products and are largely mixed therein, the amount of the to be cleaved The hydrocarbons are dimensioned so that per 1 Nm ^{3 of} oxygen 3.0 to 1.0, preferably 2.5 to 1.5 kg, correspond to the hydrocarbons to be cleaved, and the amount of the circulated and used to quench the reaction mixture soot-containing liquid cleavage products are sufficient to lower the temperature of the reaction mixture to below 500 ° C. 2. The method according to claim 1, characterized in that that the flames in the reaction chamber are directed from bottom to top. 3. The method according to claim 1 and 2, characterized in that the inner walls of the reaction space be rinsed from above with soot-containing liquid fission products. 4. The method according to claim 1 to 3, characterized characterized in that the products formed during the cleavage boiling above 85 ° C in one Amount of 30 to 150% of the hydrocarbons to be split are returned to the burner will. Considered publications:
German Patent Nos. 1014 275, 1059 898; British Patent Nos. 795 688, 802 226. 1 sheet of drawings © 309 537/420 2.