US1846803A - Production of cracked hydrocarbons - Google Patents

Description

Lsmos Feb. 23, 1932. T. T. GRAY PRODUCTN OFCRACKED HYDROCARBONS Filed March 5, 1926 AKH Syvum/WOZ @13 @1% tou/1% W Patented Feb. 23, 1932 UNITED STATES THOMAS T. GRAY, OF ELIZABETH, NEW

CORPORATION, OF NEWARK, NEW

Pantani*l OFFICE PRODUCTION OF CRACKED HYDROCARBON S Application led March 3, 1926. Serial No. 31,900.

This invention relates to the refining of cracked hydrocarbons such for example as lcracked kerosene or gasoline.

Cracked distillates are characterized by the property of leaving a considerable residue when evaporated in the presence of a1r T his residue is termed gum, and its determlnatlon by evaporation is called the gum test. Gasoline yielding high residues in this test 1s less desirable as motor fuel than low gum test gasoline. The nature of the substances which cause the formation of gum on evaporation of the gasoline is not known although the Weight of chemical authorities seems to lean toward the opinion that they are various unsaturated compounds which have a tendency to oxidize to aldehydes or peroxides during evaporation. That they are not sulphur compounds is shown by the fact that the highest gum tests I have encountered havel been in the case of highly cracked products of vapor` phase cracking processes substantially free of sulphur.

In my Patent No. 1,340,889 I have disclosed a` method of treating cracked hydrocarbon products -which consists in passing the products in vapor form in contact with fullers earth whereby the unstable unsaturated hydrocarbons therein are polymerized. Hydrocarbon products refined according to this method are substantially reduced in gum.

An object of this invention is to produce cracked hydrocarbon products such as kerosene and gasoline of still lower gum content.

I have found that if cracked products normally yielding high residue in the gum test are subjected in liquid phase to the action of certain metals and their oxides, of which copper, coppe-r oxide and zinc may be cited as examples, and the cracked products which have been so treated are subsequently vaporized and condensed, the resulting product has a materially lower gum test.

I have also found that if such products are subjected in vapor form to the action of the same materials, the residue therefrom in the gum test is materially increased over that from crackedproducts treated with fullers earth alone according patent. In view of this, I am of the opinto the method of my` ion that the subjecting of such products in liquid phase to the action of these treating materials results in the formation at this stage of the undesirable gums which, when the distillate is vaporized for fractionation, either remain in liquid form or are condensed in the fractionating device and removed.

The subjecting of the cracked products to the action of the treating material may be accomplished at any stage of the refining process While the product is in liquid phase or during vaporization and may be done in any one of a number of ways. For example, the cracked product may be distilled and condensed in the usual manner and then subjected to redistillation with the treating material placed in the still. I prefer, however, to combine the treating operation with the cracking operation, thereby utilizing the elevated temperature and pressure incident to the cracking operation. However, it is to be understood that in any event the cracking operation will have been completed before the product is contacted with the de-gumming material. A convenient way of practicing this invention is in connection with a cracking unit of the type where a heavy oil is heated in a tube furnace and is allowed to vaporize in a chamber removedfrom the main source of heat. In such a case, the treating material may be placed between the crac-king unit and the vaporization chamber or in the va-I porization chamber itself. In the latter instance, the treating material should be so arranged with the vaporization chamber that the heated oil contacts with the treating material while it is in liquid phase.

Other objects, novel features and advantages ofthe invention will be apparent from the following specification and accompanying drawings wherein the single ligure represents one form of apparatus for practising the invention.

In the apparatus disclosed in the drawing l0 1s a furnace in which is arranged the cracking coil 11 of a cracking unit of the tube type to which hydrocarbon oil is supplied from a suitable source of supply (not shown) through a pipe 12 controlled by the valve 13. The heated oil is discharged from the cracking coil through a pipe 14 to either oneof the holders 15, the inlet of each of 4which is controlled by a valve 16 and the outlet of each of which is controlled by a valve 17. Within each holder 15l is a suitable supply of a material for treating the hydrocarbon. The holders 15 discharge into a vaporization chamber 18, the outlet 19 of which leads to a dephlegmator 2() and is controlled by a valve 21 by means of which the cracking pressure may be regulated. A pipe 22 controlled by the valve 23 forms a by-pass around the holders 15 to the chambers 18, and may be used to pass the heated hydrocarbon directly to the chamber 18, if desired. From the dephlegmator a pipe 24 leads to a `condenser 25. A pipe 26 leads from the vaporization chamber 18 to conduct back into the cracking coil by way of the pipe 12 any residue collecting in the bottom of the A chamber. A pipe 27 leads from the dephlegmator 20 to conduct back to the cracking coil through the pipe 12 any condensate which may have accumulated in the bottom the dephlegmator. A pump 28 is provided to return the condensates to the cracking coil.

The material contained in the holders 15 is preferably copper oxide, although it may be copper or some other metal, oxide or compound Which reacts with the oil or distillate in the same way that copper oxide does. While copper or either of its two oxides advantageously may be used as the treating material, I prefer to use cupric oxide. According to my present theory, the treating material reacts with some constituent in the hydrocarbons, probably an unsaturated compound, to produce a gum. When the hydro-- carbons are vaporized and passed through thedephlegmator 20, the gum either remains in the vaporization chamber in liquid form or is condensed in the dephlegmator and collects in liquid form at the bottom. In any event, the fraction discharged from the dephlegmator has been so treated that, when subjected to the usual gum test, the residue is materially less than the residue from products from the same oil which have not been so treated. It may be that gum has been formed and removed before the final rectification of the product or it may be that the substances which would normally have produced gum in the gum test have been converted into other substances which do not produce gum when subjected to the gum test.

In the apparatus herein disclosed, the operation which may be termed degumming, is combined with the cracking operation, but subsequent thereto, thereby taking advantage of the elevated temperature and pressure used in cracking. The degumming operation may be performed with other types of apparatus,l but the combination with the cracking operation is very eicient,

as the heat of the cracking operation is used degumming operation performed by subject ing the oil While in the still to the action of the degumming material.

In the apparatus disclosed, the heavy oil is introduced into the cracking coil 11 where it is heated, after which it Hows by Way of the pipe 14 to the holders 15 Wherel it is subjected While under pressure to the action of the material therein contained. The treated material is then led to the vaporization chamber 18 Where it is converted into vapor by reduction of the pressure. The vapors are then led through the pipe 19 to the dephlegmator 20 where they are rectiiied and the fraction obtained is fed to condenser box 25. The liquids collected in the chamber 18 and dephlegmator 20 are returned for recirculation by means of the pipe"26 and 27. The temperature is such that the cracking operation is completed in the still and the pressure is such that the cracked product is in liquid phase While in contact with the treating material.

Although the holders 15 have been disclosed between the cracking coil and the vaporization chamber, the degumming operation might equally well be performed in the vaporization chamber. It is essential only that the degumming agent be so disposed that the cracked hydrocarbon comes in contact with it after it has been subjected to the cracking temperature and pressure and while itisin liquid phase. It is therefore apparent that the process might be accomplished in connection with the redistillation of previously cracked products. The holders 15 may Well be of the type disclosed in applicants copending application Ser. No. 82,114, filed Jan. 18, 1926 in which is disclosed an apparatus for bringing liquids into intimate contact with solid treating material.

It is understood, of course, that the practise of this process is not limited to the particular apparatus herein disclosed, but may be practised in any suitable apparatus so long as the conditions above specified with respect to the phase of the product in which it is treated by the degumming agent are observed. It should also be noted that although the process has been specifically described as being carried on in practical connection with a cracking operation, it may also be practiced in connection with re-run distillation, but in any event, the invention is characterized by the fact that the product treated has been cracked and removed from the cracking zone before being contacted in liquid phase'with the catalyst and that no cracking takes place in the presence of the catalyst. My catalyst is rather a polymerizing or gum-forming catalyst and in either case, the gasoline is separated by subsequent vaporization from the gum formed during the treatment.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is 1. The process of producing cracked gaso line of loW gum test Which comprises cracking a hydrocarbon oil, removing the cracked product from the cracking zone and subsequently contacting the same in liquid phase at substantially cracking temperature with a non-hydrogenating catalyst containing copper and favoring the formation of gum, and then vaporizing the liquid and obtaining gasoline by rectication of the resulting vapor.

2. The process of producing cracked gasoline of low gum test which comprises crackinga hydrocarbon oil, removing the cracked product from the cracking Zone and subsequently contacting the same in liquid phase at substantially cracking temperature with copper oxide, then vaporizing the liquid and obtaining gasoline by rectification of the resulting vapor.

3. The process of producing cracked gasoline of loW gum test Which comprises cracking a hydrocarbon oil, removing the cracked product from the cracking zone and subsequently contacting they same in liquid phase and at substantially cracking Vtemperature and pressure With a non-hydrogenating catalyst containing copper and favoring the formation of gum, then reducing the pressure to vaporize at least part of the liquid and obtaining gasoline by rectification of the resulting vapor.

4. The process of producing cracked gasoline of low gum test which comprises cracking a hydrocarbon oil, removing the cracked product from the cracking Zone and subsequently .contacting the same in liquid phase at substantially cracking temperature and pressure With copper oxide, then reducing the pressure to vaporize at least part of the liquid and obtaining gasoline by rectification of the resulting vapor.

5. The process of producing cracked gasoline of low gum test which comprises contacting cracked hydrocarbon distillate in liquid phase and at substantially cracking tem perature With copper oxide7 subsequently vaporizing the liquid and obtaining gasoline from the vapor by rectification.

6. The process of producing cracked gasoline of 10W gum test which comprises contacting cracked hydrocarbon distillate in liquid phase and at substantially cracking temperature With a non-liydrogenating catalyst containing copper and favoring the production of gum, subsequently vaporizing the liquid and obtaining gasoline from the vapor by rectification. i

7. The process of producing cracked gasoline of loW gum testwhich comprises contacting cracked hydrocarbon distillate in liquid phase and at substantially cracking temperature and pressure With copper oxide, subsequently reducing the pressure to effect vaporization from said liquid and obtaining gasoline from the vapor thus obtained by

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