US3316169A - Catalytic hydrocracking of hydrocarbons with the use of halogen and sulfur activators - Google Patents

Description

United States Patent Cfitice 3,3 I 6,169 i atented Apr. 2 5, 1967 3,316,169 CATALYTIC HYDROCRACKING F HYDROCAR- BONS WITH THE USE OF HALOGEN AND SUL- FUR ACTIVATORS Reese A. Peck, Fishkill, Donald A. Messing, Glenham, and Edward T. Child, Brinckerhoff, N.Y., assignors to Texaco Inc., New York, N.Y., a corporation of Delaware No Drawing. Filed Oct. 16, 1964, Ser. No. 304,493

4 Claims. (Cl.

aromatic rings with subsequent rupture of the cycloparaffinic structure, the isomerization of parafiinic compounds into isoparafiinic compounds and the dealkylation of alkyl aromatics. Ordinarily, the charge to a hydrocracking unit will comprise hydrocarbons boiling above the range of the desired product. For example, if a motor fuel is desired, the charge to the hydrocracking unit will have an initial boiling point of about 400-450 F. whereas if the charge to the hydrocracking unit will have an initial boiling point of 550600 F. Advantageously, charge stocks such as straight run kerosine and gas oil stocks obtained by the distillation of crudes and from catalytic cracking, light distillates obtained from coal and shale may be charged to the hydrocracking unit. Ordinarily, product boiling above the desired end point is recycled to the hydrocracking unit.

Hydrocr-acking is preferably carried out in the presence of a catalyst which generally contains two components, a hydrogenating component and cracking com ponent. Numerous hydrogenating components have been disclosed in the prior art such as Group VIII metals for example platinum, palladium and nickel and the oxides and sulfides of molybdenum, nickel, tungsten, and cobalt, and the like or mixtures thereof. The hydrogenating component is supported on a cracking base which advantageously is acidic in nature. Such bases comprise refractory oxides of one or more elements of Groups II, III, and IV of the Periodic Table. Suitable cracking supports include silica-magnesia, silica-alumina, silicaalumina-zirconia and the like. Synthetic and natural Zeolites are also satisfactory in this respect. In some instances, the cracking support may be activated by treatmeat with an inorganic acid such as hydrofluoric acid or hydrochloric acid.

The present invention is particularly but not solely concerned with the use of catalysts comprising as the hydrogenating component the oxide or sulfide of cobalt and/or nickel supported on a silica-alumina cracking base having a high silica content. While these catalysts are eminently suitable for hydrocracking of various petroleum charge they are subject to an acute loss of catalyst activity amounts of nitrogen.

As a measure of the catalyst activity it is customary to institute a hydrocracking reaction and conduct the process at certain conditions of temperature, pressure,

space velocity and hydrogen rate to obtain and maintain a predetermined conversion of the charge into material boiling point. As the reaction subject to loss in activity and, to compensate for the reduced activity, the temperature maintain the constant This increase in temperature necessary to maintain the desired with a charge containing 1 F. per hours. When hydrocracking to produce a high octane motor preliminary treatment for nitrogenremoval or the process may pay an excessive economic penalty by Way of frequent catalyst regeneration and reactivation.

Reaction conditions within the hydrocracki-ng unit generally include a temperature range of about 450-800 F. although a temperature of from 500 to about 750 F. is preferred. Pressures usually range from about 500 to 10,000 p.s.i.g. or higher, a preferred range being from 1000 to 3000 p.s.i.g. The hydrogen containing gas rate this respect the term hydrogen includes impure hydrogen,

hydrogen. Preferably, the space velocity, that is, volumes of liquid charge per volume of catalyst per hour will be between 0.5 and 3 although rates ranging from 0.1 to 10 may be used.

It is an object of the present invention to increase the activity of a hydrocracking catalyst. Another object is hydrocracking catalyst. Another a hydrocracking operation. A still further object is to accomplish greater conversion into hydrocracking products at lower temperatures. These and other objects will be obvious to those skilled in the art from the following disclosure.

According to the present invention the hydrocracking is carried out in the presence of a halogen-containing compound and a sulfur-containing compound. These compounds may be introduced separately into the reactor or may be introduced into the admixture with the hydrogen or as a component of the hydrocarbon charge stock. Preferably the halogen is in the form of an organic compound but any compound which is convertible to hydrogen halide under the reaction conditions is satisfactory. Suitable halogen containing compounds include alkyl and aryl halides such as chloroform, carbon tetrachloride, dichloroethane, chlorobenzene and the like. Preferably an organic compound having a high ratio of chlorine to carbon is selected.

The sulfur may be introduced in the form of H 3 or in the form of an organic sulfur-containing compound such as carbon disulfide, tertiary-butyl disulfide, lower .lkyl mercaptans such as methyl mercaptan and ethyl nercaptan or other compounds convertible to H S under eaction conditions.

To be effective sulfur should be present in the reaction zone in an amount of at least 50 p.p.m. preferably be- .ween about 100 and 2000 p.p.m. by weight based on the nydrocarbon charge to the hydrocracking zone. However, when the charge contains more than 5 p.p.m. nitrogen, high concentrations of sulfur have no appreciable effect on the life of the catalyst unless halide is also present.

Advantageously, when the charge contains more than about 5 p.p.m. nitrogen the halogen content is maintained at a level such that the halogenznitrogen atomic ratio is at least 1 and not more than about 80 and preferably is between about 20 and 70.

Example 1 In this example a charge stock containing varying amounts of nitrogen is hydrocracked at a temperature of 650 F., a pressure of 1500 p.s.i.g., a hydrogen rate of 15,000 s.c.f. per barrel over a NiO, S 0, A1 catalyst at a space velocity of 1.0 v./v./ hr.

The results in Table 1 show the effect of the increasing nitrogen concentration on the aging rate of the catalyst.

TABLE 1 Nitrogen content of Aging rate feed (p.p.m.): F./l00 hrs.) 1 1.7 3 6.6 5 11.0 22.2 35

Example 2 Aging rate F./100 hrs.)

S content (p-p 01 content (D-p-rn.)

The data set forth in Table 2 show that in the case of a charge stock having a nitrogen content of 15 p.p.m., added halogen in conjunction with less than 50 p.p.m. sulfur, and added sulfur with no added halogen, does not improve the rapid aging rate but that when sulfur in excess of 50 p.p.m. in conjunction with added halogen is used, the aging rate of the catalyst is equivalent to that when there is not more than about 2 p.p.m. nitrogen in the charge. It is also to be noted from this example that sulfur in excess of 2000 p.p.m. in the absence of added halogen has no effect in improving the aging rate of the catalyst.

Example 3 In this example, a gas oil, mildly catalytically treated for sulfur and nitrogen removal, obtained from the atmospheric distillation of Southern Louisiana crude and containing p.p.m. nitrogen and 40 p.p.m. sulfur is hydrocracked over a catalyst containing 5.7% NiO on a silica-alumina cracking base at 620750 F., 1500 p.s.i.g., 1.0 v./v./hr. and 6000 s.c.f. hydrogen per barrel of charge. Halogen in the form of chlorobenzene and sulfur in the form of tertiary-butyl disulfide is added in varying amounts to the charge. The results are shown in the following table.

TABLE 3 Cl content (p.p.m.)

Sulfur content (p p Aging rate F./100 hrs.)

This example shows the varying effect of different chlorineznitrogen atomic ratios on the catalyst aging rate using gas oil charge stocks having a sulfur content of 60 p.p.m. and 10 and 15 p.p.m. nitrogen respectively under constant reaction conditions, only the temperatures being varied to maintain 40% conversion.

TABLE 4 Catalyst aging rate, F./100 hrs.

N, p.p.m.

Atomic Ratio, in charge C1:N

The data in Table 4 show that with .a charge containing 60 p.p.m. sulfur and 10 or 15 p.p.m. nitrogen, the catalyst aging rate is rapid but is slowed considerably with the addition of halogen.

The advantages of the present invention are not restricted to the treatment of charge stocks containing 5 or more p.p.m. combined nitrogen. The following example shows the improvements obtained when the invention is applied to a charge stock containing 1 p.p.m. nitrogen.

Example 5 In this example two charge stocks A and B are used, A containing 1 p.p.m. nitrogen with B substantially identical to A except for a nitrogen content of 15 p.p.m. Charge stock B is first hydrocracked under the conditions set forth in Example 3 and after determination of the aging rate ch-arge stock A is substituted as charge to the reaction zone. The only effect in this instance is shown by a reduction in the aging rate. In an additional run charge stock B with halogen and sulfur added as indicated below is hydrocracked for a period of time sufficient to determine the aging rate after which charge A is substituted. However, in this case there is no appreciable change in the aging rate but there is an increase of approximately 35% in the conversion.

TABLE 5 Dichlorot -Buty1 Aging rate Percent Charge ethane disulfide F./100 hrs.) conversion (PP- (ar From a consideration of the runs made with charge stock A halogen are added to a low-nitrogen charge, it is possible to operate at 40 F. lower and still get the yield obtained When no sulfur and halogen is added.

Advantageously, the halogen is recovered from the reaction zone eflluent Obviously, many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore, only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. In a process in which a hydrocarbon charge stock containing more than 5 ppm. nitrogen and boiling in the gas oil range is contacted with a hydrocracking catalyst under hydrocracking conditions and in which the the hydrocarbon charge, the ratio being between 17 and process of claim 1 in which the halogen is References Cited by the Examiner UNITED STATES PATENTS 3,213,012 10/1965 Kline et al.

DELBERT E. GANTZ, Primary Examiner. ABRAHAM RIMENS, Examiner.

Claims (1)

1. IN A PROCESS IN WHICH A HYDROCARBON CHARGE STOCK CONTAINING MORE THAN 5 P.P.M. NITROGEN AND BOILING IN THE GAS OIL RANGE IS CONTACTED WITH A HYDROCRACKING CATALYST UNDER HYDROCRACKING CONDITIONS AND IN WHICH THE CATALYST IS SUBJECTED TO A LOSS IN ACTIVITY, THE IMPROVEMENT WHICH COMPRISES REDUCING THE RATE OF LOSS OF ACTIVITY OF THE CATALYST BY CONDUCTING SAID HYDROCRACKING IN THE PRESENCE OF A HALOGEN COMPOUND AND A SULFUR COMPOUND PRESENT IN AN AMOUNT SUFFICIENT TO SUPPLY AT LEAST 60 P.P.M. SULFUR BY WEIGHT BASED ON THE HYDROCARBON CHARGE, THE HALOGEN TO NITROGEN ATOMIC RATIO BEING BETWEEN 17 AND 99.