US1838893A - Cracking oils - Google Patents

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CRACKING OILS Filed April 7. 192

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'PATENT OFFICE- IOBT-ON-THE-MAIN, GERMANY, A COKPORA'IION 0F GERMANY CRACKING OILS Application filed April 27, 1927, Serial No. 187,044, and in GermanyMay 6, 1926.

Hydrocarbons of lower'boiling. point can readily be obtained from those of higher boiling point by the known cracking processes, by passing the hydrocarbons to be cracked through pipes, retorts and the like, at a temperature of from about 500 to 600 C. and, as occasion requires, under increased pressure. In such operations,

deposition of carbon takes place in the reaction chambers, thereby hindering the workmg operations and necessitating frequent cleaning of the apparatus.

We have found that this drawback may be easily overcome and that oils of any kind and similar materials of high boiling point may be converted with a good yield into products of lower boiling'point by passing the vaporized original materials, preferably at high velocity, over a highly heated heating device of metal or other materials, the dimensions of which are small in the direction of the flow of the hot vapors, but may be considerable at right angles thereto. It is advisable, though not essential in this case that the heating device should be intermittently or continuously treated with a blast of air, hydrogen, or gases such as steam, ammonia, and the like, capable of furnishing hydrogen. Mechanical cleaning devices, adapted to be operated while the apparatus is working, may also be provided, toenable any deposited carbon to be removed Without stopping the work. The vaporous products are cooled beyond the heating device, preferably in such a way that the hydrocarbons of higher boiling point are condensed, whilst the gases formed during the process, and

containing a large proportion of olefines and hydrocarbons of low boiling point, are led through a second condensing plant, where the last named are separated. The hydrocarbons of high boiling point, separated in the first condensing apparatus, can be vaporized again and passed over the heating device. The gases, rich in olefines, escaping from the second condensing apparatus after the condensation of the hydrocarbons of low boiling point, may be passed over porous substances, such as active charcoal and the like, in order to recover any benzines still present however, a considerable in the form of vapor therein. The gaseous olefines, such as ethylene, propylene and the like, can be transformed into benzines and 1 ure 1 in vertical cross-section an apparatus for cracking oils in which a heating device is arranged in the vapor space. Figure 2 is a horizontal cross-section of the heating device.

The invention, however, is in no way restricted to the employment of the apparatus shown.

In a deep enamelled Vessel A as shown in i b Figure 1, which is filled to the extent of about one third with American petroleum boiling between 170 and 270 0., there is arranged a heating device B, composed of a plurality of nickel-chromium tubes as shown in Figure 2, maintained at a temperature of about 700 by passing a current of hot gases therethrough. The heating device B can be kept under observation through a peephole F. Below the heating device is mounted a baflie plate C, which prevents the boiling oil from spurting up against the heating device B. The constituents of high boiling point in the oil vapors which have passed the heating device B and undergone partial decomposition,

are condensed in a dephlegmator D, the tem-.

perature of which is maintained at about 100 C. and run back into the vessel A. The resulting light benzines and the gases containing olefines pass off to a condenser E, where the light benzines are condensed. About 45 per cent of the original material is transformed into benzines boiling between 7 0 and 170 C. and the remainder is converted into gas consisting of 64 per cent of ethylene, propylene and butylene, 5 per cent of hydrogen, 21 per cent of ethane and methane, and 10 er cent ofnitrogen. No'deposit of carbon is ormed on the heating prolonged working. 7

According to the above method of working the heating device may also be electrically heated, preferably with low-tension current of very high amperage. Theheating device device B, even after may also be shaped in difierent ways.

It is advisable to prevent the boiling liquid from spurting against the heating device, because otherwise carbon might be deposited on the latter and so retard the transmission of heat and lessen the yield of hydrocarbons of low boiling point. If, as may be easily ascertained by observation through the peephole, any carbon has been deposited on the heating device, small quantities of air, hydrogen, steam or ammonia can be projected on to the heating device without stopping the process. Deposits of carbon, or incrustations due to the mineral constituents of the mineral oils and the like can also be removed by mechanical devices While the work continues. This constitutes a great advantage due to the relatively small dimensions and at the same time the maximum mechanical resistance of the heating device.

What we claim is:

1. In the cracking of oils of any kind and similar materials the step of effecting the decomposition by passing the materials in the vapor state over a heating device the dimensions of which are small in the direction of the flow of the vapors and which is heated by means of a current of hot gases passed through the interior of the said heating device and which is arranged in a single plane and heated to'at least red heat.

2. A process for the cracking of hydrocarbon oils which comprises distilling the vapors of American petroleum over a heating device the dimensions of which are small in the direction of the flow of the vapors, but large at right angles thereto which is maintained at a temperature of about 700 C. by passing a current of hot gases through the interior of the said heating device, condensing the constituents of high boiling point contained in the vapors issuing from the said treatment and returning the condensate for a further treatment by vaporization and treatment of the vapors thus obtained with the said heating device.

In testimony whereof we have hereunto set our hands FRITZ WINKLER.

CARL MESSERKNEGHT.

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