DE2206115A1 - Process for increasing the octane number of light gasoline fractions containing n-paraffins - Google Patents

Description

. SHELL INTERNATIONAL RESEARCH MAATSCHAPPIJ N.V. The Hague, Netherlands

¹¹ Process for increasing the octane number of light gasoline fractions containing η-paraffins "

Priority: February 11, 1971, the Netherlands, no.7101797 March 4th 1971, the Netherlands, Mr. 7102929

The invention relates to a method for increasing the octane number of η-paraffins containing light gasoline fractions with more than 85 percent by volume of paraffins with 5 or 6 carbon. : atoms and less than 5 percent by volume of aromatics. n-paraffins have a low octane number and therefore have an unfavorable effect on the octane number of light gasoline fractions that contain η-paraffins. In order to increase the octane number of these light gasoline fractions, the η-paraffins contained therein can be converted into compounds with a higher octane number, such as isoparaffins and aromatics, or the η-paraffins can be removed from the fraction, for example by selective hydrocracking. Although the selective hydrocracking of the η-paraffins contained in light gasoline fractions of the type described above generally causes an increase in the octane number of the fraction, the use of this process is in a number of cases from the standpoint of economy

209835/1119

out not justified. In this regard, decisive factors are the loss of yield in the C ₁ - fractions and the loss in yield in the C ₁ - fractions per unit increase in the octane number which occurs when the process is used. In general, it can be said that the selective hydrocracking of η-paraffins present in light gasoline fractions of the type described above, with regard to the increase in the octane number of these fractions, is only justified from the standpoint of economy if the loss in yield of the C ₁ - fractions is less than 25 percent by volume, and the loss in yield of the C ^ fractions per unit of increase in octane number is less than 3.5 percent by volume It has now been found that these two requirements are met when the light gasoline fraction is χ percent by volume Contains Cg paraffins with a volume ratio of iso to normal compounds of y, where χ ^. 25, y> 2 and 65y? -2 χ + 80.

The invention accordingly relates to a method for increasing the Octane number of light gasoline fractions containing η-paraffins, in which a light gasoline fraction containing

a) more than 85 percent by volume of paraffins with 5 or 6 carbon atoms, -

b). less than 5 volume percent aromatics, and

c) χ Volume percent of Cg paraffins with a volume ratio- " nis of iso- to normal-connections' of y, where χ ^ 25, y ^ 2 and the relation 65 y ^ 2 χ + 80 holds a selective hydrocracking with regard to η-paraffins

is subjected.

209835/1119

The process according to the invention is preferably used for light gasoline fractions with more than 90 percent by volume of paraffins with 5 or 6 carbon atoms and / or less than 2 percent by volume of aromatics. With regard to the amount of C ^ paraffins contained in the light gasoline fraction and their volume ratio of iso- to normal compounds, it can be pointed out that light gasoline fractions in which χ -γ / 40 and / or y are preferably used as starting material for the process according to the invention > 4 is. If that happens

, the method according to the invention in the case of a C, - containing paraffins Light gasoline fraction is used, is preferably a fraction with a ratio of iso to normal compounds of C, paraffins of at least 1 used. The final boiling point the light gasoline fraction is preferably below 75 ° C

• The method according to the invention is also preferably used at Light gasoline fractions containing sulfur, especially those with a sulfur content of 0.0002 to 0.0010 Weight percent, used »

Light gasoline fractions that are specified under a), b) and c) above Requirements can expediently by isomerizing light, paraffinic hydrocarbon fractions can be obtained. As is known, the isomerization of light in refined hydrocarbon fractions, in which η-paraffins are converted to iso-paraffins, e.g. used to increase the octane number of these fractions. The isomer still contains a certain amount depending on the conditions under which the isomerization takes place of ri-paraffin with a, as already mentioned, low

2 0983 5/1119

Octane number. By subjecting such an isomer to selective hydrocracking, η-paraffins are removed from it and the octane number is increased. For this reason, the method according to the invention is preferred for light gasoline fractions applied; obtained by isomerizing light paraffinic hydrocarbon fractions.

Light gasoline fractions, which may be suitable for processing by isomerization, often contain a considerable proportion of CY and C, paraffins. The C _r paraffin fraction of these light pamffini sob en hydrocarbon fractions is normally composed of n-pentane and iso-CY paraffins. Compared to n-pentane, isc-CY paraffins have a high octane number. It is not possible to increase the octane number of these CY paraffins either by isomerization or by selective hydrocracking. On the contrary, it exists among the

in the isomerisicren conditions used and especially μ the conditions prevailing in the subsequent selective hydro splitting there is a risk that some of these valuable iso-CY paraffins will be lost through cleavage. In addition to the risk of splitting, there is also the presence of iso-paraffins in

which is a starting material for a with the aim / conversion of Isomerization carried out η-paraffins in iso-paraffins is also undesirable because their presence in the starting material leads to less η-paraffins being converted. Finally, it applies both to the isomerization process and to the selective hydrocracking that the presence of iso-paraffins in the starting material has an adverse effect on this process, because the iso-paraffins, not for

2 0 9835/1 * 119

Conversion in these processes are suitable, but nonetheless take up part of the reactor volume and therefore reduce the efficiency of the plant. Fortunately, however, due to their low boiling point, the iso-Cc paraffins can easily be separated off by distillation from mixtures with n-pentane and higher paraffins, and distillation is also one of the usual process steps in the combined process of isomerization and selective hydrocracking described above First of all, the starting material for the isomerization process, which preferably consists essentially of C ₁ - and CV paraffins, is generally obtained by simple distillation of a roling oil. It is also customary to remove the C7 hydrocarbons from the isomerizate by distillation before it is used as the starting material for selective hydrospecification. And finally, the product from the selective hydrocracking is usually freed from the C "" cleavage products formed in this reaction by distillation.

It has been found that using the combined method described above with light paraffinic hydrocarbons. hydrogen fractions with C ^ paraffins a considerably better result is achieved if at least a portion of the iso-C, paraffins is removed from the fraction to be isomerized and / or from the isomerizate. A preferred embodiment of this invention therefore relates to a Process for increasing the octane number of a light gasoline fraction, in which a light paraffinic hydrocarbon fraction isoinerized with n-paraffins and Cc-paraffins and then at least one

209835/1111

Part of the η-paraffins is removed from the isomerizate by selective hydrocracking, with at least part of the iso-Cv-paraffins separated from the light paraffinic hydrocarbon fraction to be isomerized and / or the isora will.

The method according to the preferred embodiment used the invention is against a process in which the isomerization and the selective hydrocracking takes place without separating the iso-Cp paraffins, much more flexibly. The last

. This procedure results in addition to that by the Hydrospa1 ~ - '

The product obtained is an iso-GM fraction with a high octane number. This iso-C, - ~ paraffin fraction is excellent as a component for the scheduled blending of gasoline, e.g. as a sealing component for the product from the hydrofraction. By changing the blending ratio of the separated iso-Cp paraffin fraction and the product from the hydrocracking The present process allows the production of gasoline mixtures with different octane numbers according to plan.

The method of this preferred embodiment of the invention, in which, as an additional feature, the separated iso-Cc-paraffins with the product of the hydrocleavage be blended offers a process in which isomerization and selective hydrocracking without separation the iso-Cc paraffins takes place, the advantage that in the Manufacture of an end product with a certain octane number, starting from a given starting material, both the loss of yield occurring in this production

C _I - ⁺ fraction as the loss in yield for the CK ⁺ fraction ⁵ 20,983 $ / 1113

per unit of octane number, is lower.

The isomerization stage preferably included in the process according to the invention is preferably used in the case of a light paraffinic hydrocarbon fraction with more than 80 percent by weight and in particular more than 85 percent by weight of paraffins with 5 or 6 carbon atoms. Furthermore, the light paraffinic hydrocarbon fractions used as feedstock for the isomerization stage preferably contain less than 15 percent by weight and in particular less than 10 percent by weight of cyclic hydrocarbons. Can reactions material in terms of the content of C, "· paraffins in the feedstock" enwassor for Isomerisationsstufe serving light paraffinic carbon indicated v / ground that fractions having more than 10 percent by weight and in particular with Mohr than 20 percent by weight of C _r paraffins As noted above, the light paraffinic hydrocarbon fraction, in which the isomerization process is preferably used, consists essentially of a mixture of C _r and C g paraffins This light gasoline fraction present Cg paraffins is preferably lower than h and in particular lower than 2. The final boiling point of the light gasoline fractions is preferably lower than 75 ° C. A particularly suitable starting material for the present process is a distillate fraction obtained from the distillation of crude oil at atmospheric pressure has been t.

209835/1119

In the isomerization stage preferably included in the process according to the invention, at least some of the iso ~ C (paraffins present in the light paraffinic hydrocarbon fraction and / or in the isomerizate should be separated off. This separation is preferably carried out in such a way that from those in the light paraffinic hydrocarbon fraction Hydrocarbon fraction and / or iso-C ^ paraffins present in the isomer, more than 75 percent and in particular more than 85 percent are separated off paraffinic Kuhlenwasserstoffraktion and / or the isomerate small amounts of n-pentane, which enter Fraliticn in the iso-C, paraffin with separated separation of i, oo - en paraffinic C _r --P.Mraffine 'from the light. Kohl em. ¹ as, se rs tof fraction and / or * the Isomcrisat is preferably carried out in such a way that the iso-CY fraction is more than 85 weight percent and insbesorid; ^! re more than 95% by weight of iGO-Cp paraffins. Ίί? Ϊ́.

Is .i around the light paraffinischc KoJilonwascertitoffraktion from dor gege Bono if zumirulcstens part D.02 ¹ iso-Cf.-Pi-iraffino entfei'iit been zunüchs t isomiirisiert, whereupon, in a preferably vcrv.'ondeten Ausführuijgßform dos erfindungßgemäßen method v the isorhorizate, from which at least part of the iso-C _r -paraffin has also been harvested, is subject to selective Ilydro cleavage.

The isomerization of the dense paraffinic carbon fraction can advantageously be carried out in the presence of hydrogen and a catalyst, one or more Group VIII metals of the periodic table on one

209835/1119

SAD ORfGiNAL

Zeolite carrier with a pore diameter of 6 to 15 S contains. A catalyst based on morclenite, in particular a catalyst containing platinum based on mordenite, is preferably used as the catalyst for the isomerization. Suitable reaction conditions in the isomerization process using a catalyst based on zeolite with a pore diameter between 6 and 15 $ are a temperature of 100 to 4.00 ⁰ C, a pressure of 5 to 50 kg / cm, a Rauiriströmungsgeschwindigke.it of 0.5 to feeding in 10 liters per liter of catalyst per hour and a haul \ ^r erhältnis hydrogen: feeding in of 0.5: 1 to 10: 1.

The selective hydrocracking of the light gasoline fraction from which at least part of the η-paraffins contained in it has been removed can expediently be carried out in the presence of a catalyst which contains one or more catalytically active metal components on a porous support with a uniform pore diameter of between 4 and 6 A contains. Zeolites are preferably used as porous carrier materials with a uniform pore diameter of between 4 and 6 Λ. Examples of zeolites with a uniform pore diameter of between 4 and 6 R, which can be used as supports for the present catalysts for hydrocracking, are erionite, chabazite, zeolite A, zeolite T, Phillipsite, Epistilbit, Levynite, Brewsterite, Dachiadite, paulingite and clinoptinolite. Both natural and synthetic zeolites are useful as Trugermaterialien for the present hydraulic cleavage catalysts, provided they have a uniform Porendurchme3ser of 4-6 £.

209835/1119

Both natural and synthetic zeolites often contain a certain amount of alkali metal ions. To get the zeolites for the Use as a carrier material for catalysts in hydrocarbon conversion processes To make it more suitable, a part of the alkali metal ion contained in them is preferably replaced by other cations, especially hydrogen ions and / or ammonium ions and / or ions of rare earth metals. For their use as a carrier material for catalysts for hydrocarbon conversion processes are preferred Zeolites with an alkali metal content of less than 1 percent by weight and in particular less than 0.1 percent by weight used.

The method according to the invention is primarily used an IIydrospartungskat'ily £., o.tors on Zeolithbasiö carried out, the as catalytically active Heta'Ll constituents one or contains several metals from groups Ib, Hb, Via, VIIa and / or VIII of the periodic table, examples of such metals are copper, zinc, molybdenum, tungsten, rhenium, the metals of the iron group, and the metals of the platinum and pallad youth groups. Catalysts with a noble metal as catalytically active: · ' Metal components generally contain 0.05 to 5 parts by weight and preferably 0.1 to 2 parts by weight of metal per 100 parts by weight of carrier material. Very suitable precious metals are palladium and platinum. Catalysts with a base metal or a combination of non-noble metallone as a catalytically active metal component generally contain 0.1 to 35 parts by weight of metal or metal combination per 100 parts by weight of carrier material. Very suitable for plydro cleavage

209835/1119

Catalysts contain a combination of 0.5 to 20 parts by weight and in particular 1 to 10 parts by weight of a Group VIII base metal and 1 to 30 parts by weight, in particular 2 to 20 parts by weight of a metal from group VIa and / or VIIa per 100 parts of the carrier material. Particularly suitable metal combinations are combinations of Nikkei and / or cobalt with tungsten and / or molybdenum and / or Rhenium. Similar very suitable hydrocracking catalysts are catalysts containing from 0.1 to 35 parts by weight and especially 1 to 15 parts of nickel per 100 parts by weight of carrier material.

The metals can be in any conventional manner, such as by. Impregnation, sintering or ion exchange applied to the zeolite. After aar b, the catalytically active I-'k; tall component is attached to the. The carrier is usually dried and the Eat & lyf-.ator is then calcined. Catalysts for the Hydro opal are usually used in the form of particles with a diameter of 0.5 to 5 mm. Λ] f .; Carrier material for the present Hydrosp. Solutionpkat <'ily:. ;; i.tore] i suitable zeolites are, however, often in the form of fine powders. The zeolites can zV>. reshaped by compression into particles with larger dimensions. The reshaping is preferably carried out after the application of the catalytically active metal component, but before the calcination, in which the metals are converted into the corresponding oxides. If desired, an inorganic embedding agent or binder can be added to the zeolite during the forming process. Examples of suitable bedding or binding agents are natural clays and

2 0 9 8 3 5/1119

BATH ORIGINAL

synthetic, inorganic oxides. Before the formed particles are formed, the zeolite and the embedding or binding agent should first be mixed homogeneously. The shaped particles can be of any desired shape such as beads, spheres, pellets, tablets, briquettes, granules, etc. When embedding or binding agents are used in the preparation of the present hydrocracking catalysts, preferably shaped particles having 10 to 20 weight percent des Embedding or binding agent produced, the embedding or binding agent preferably containing no or only very few alkali metals. Uerm desired, mixtures of zeolites de support material for the present. Hj'drOsjoaltungkataly rotors may be used, provided that at least one ?. Some of these zeolites have a similar pore diameter of between 1 and 6 2 . Such zeolite mixtures kümK-u eDer.ual.1 ;; can be used together with an embedding or binding agent.

If the present hydrocracking catalysts contain a non-noble metal or a combination of non-noble metal or a combination of all catalytically active metal components, they are preferably used in their sulfidic form. The conversion of the Hydrospaltungskp.talysatoren in their sulphidic form can suitably by contacting the catalyst with a mixture of hydrogen and hydrogen sulphide in a volume ratio of 5: 1 to 15: 1 carried out at a temperature of less than 500 ⁰ C. The catalysts can also be converted into their sulfidic form by adding sulfur compounds in an amount of from 0.001 to 5 percent by weight and in particular in an amount of from 0.01 to 2.5 percent by weight

209835/1119

£ BATH ORIGINAL

carried out for feeding under reaction conditions.

Suitable conditions for the inventive hydrocracking of η-paraffins are a temperature of 250 ⁰ C to 60O ⁰ C, a pressure of 5 to 100 kg / cm, a space velocity of 0.2 to kg to 20 Iiohlenwasserstoffzuspeisung per kg of catalyst per hour and a molar ratio of hydrogen: hydrocarbon feed of 1: 1 up to 50: 1. The hydrocracking process is preferably carried out at a temperature of 300 C to 550 C and a pressure of 10 to 50 kg / cm ".

The selective hydrocracking according to the invention should be carried out in such a way that at least some of the η-paraffins in the light gasoline fraction are converted. The conditions for the hydrocracking are preferably chosen so that more than 50 percent by volume and in particular more than 1 ^ percent by volume of the n-CV paraffins present in the light gasoline fraction are subject to the hydrogenative cleavage. If the light gasoline fraction also contains n-Cc paraffins in addition to the n-Cg paraffins, the conditions for the hydrocracking are preferably chosen so that more than 40 percent by volume of these nC, - paraffins are hydrotreated. In the selective hydrocracking of light gasoline fractions according to the invention, which in addition to the nC paraffins also

Contain n-Cir paraffins, the method is further preferably carried out so that the ratio between the volume percentage of the hydrogenating cleavage subject n-Cg paraffins and the volume percentage of the hydrogenating cleavage

209835/1119 bad ome, _N AL

Ia-C ₁ - paraffins which are subject to processing has at least a value of 1.

The invention is made with reference to the following procedures explained.

A number of alternative process sequences are possible within the scope of the present invention. Six well-suited processors for increasing the octane number of _{light paraffinic hydrocarbon reactions consisting essentially of C r} . ~~ and Cg ~~ paraffins are explained in more detail in pairs with reference to the accompanying drawings: .

The process is carried out in a plant which, in the following sequence, consists of a first distillation zone (1), a tornerisicrungszone (2), a zone for selective hydrospoiling (3) and a second distillation zone (4). In the first distillation zone the ir.oC _tr -Pa ■■■ raffins are separated from the light paraffinic hydrocarbon fraction and in the second distillation zone the Cr ~ paraffins are separated from the product of the hydrocracking. According to sequence I, the iso-C ₁ --- paraffins separated in the first distillation zone are mixed with the bottom product I; the second distillation zone blended. According to sequence II, the iso-C, --- paraffins separated off in the first distillation zone are drawn off as a separate product stream. Processes I and II are excellently suited for use with light paraffinic hydrocarbon fractions of more than 15 percent by weight and especially more than 20 percent by weight

209835/1119

BAD ORfQiNAL

of iso-Cp - paraffins.

V experiencing sequences III and IV

The process is carried out in a plant which, in the following order, consists of a first distillation zone (5), an isomerization zone (6), a second distillation zone (7), a zone for selective hydrocracking (8) and a third distillation zone (9) ". In the first distillation zone iso-C, - paraffins are separated from a mixture of the light paraffinic hydrocarbon fraction; in the second distillation zone the Cc-paraffins are separated from the isomerizate and v / icck -.- r the first distillation zone Filled in and in the third distillation zone, C _L ~ paraffins are never separated from the product of the hydrocracking. After process III, the iso-Cp-paraffins separated in the eroded decomposition zone are blended with the product of the hydrocracking, which is used as the feed for the third distillation zone IV, the iso-Cc "-paraffins separated in the first distillation zone are in a separate distillation, szo ne (10) split into Ci "-paraffins and iso ~ C _r -paraffins and the latter drawn off as a separate product stream. Processes III and IV are good for use with light paraffinic hydrocarbon fractions with more than 15 percent by weight and in particular more than 20 percent by weight of iso-C ^ paraffins and / or with light paraffinic hydrocarbon fractions with a weight ratio of C. ^ -ZU Cg paraffins of greater than 1 and in particular greater than 2 are suitable ».. -... ■ __- ■■ -.

209835/1

Procedures V and VI

The process is carried out in a plant which, in the following order, consists of an isoraerization zone (11), a first distillation zone (12), a second distillation zone (13), a zone for selective hydrocracking (14) and a third distillation zone (15 ) consists. A mixture of the light paraffinic hydrocarbon fraction and recirculated n-pentane is used as a feed for the isomerization zone; In the first distillation _{zone, iso-C r} "paraffins are separated from the isomerizate; in the second distillation zone, n-pentane is separated from the product of the first distillation zone and fed back to the isomerization zone and in the third distillation zone C /" -Paraffins separated from the product of hydro-splitting

. ■ V
separates. After expiry / the iso-C, - ~~ Faraffins separated in the first distillation zone are blended with the product from the hydrocracking and serve as feed for the third distillation zone-. After sequence VI, the iso-C, - ~ paraffins removed in the first distillation _{zone are split into C, "- paraffins and iso-C r} -paraffins in a separate distillation zone (16) and the latter are drawn off as a separate product stream. Processes V. and VI are good for use with light paraffinic hydrocarbon fractions with less than 15 percent by weight and in particular less than 5 percent by weight of iso-Cc paraffins and / or with light paraffinic hydrocarbon fractions with a weight ratio of C ^ to Cg paraffins of greater than 1 and especially greater than 2, suitable.

209835/1119

The present patent application also relates to systems for carrying out the method according to the invention, as they are in the form of the process sequences are shown in Figures I to VI.

The invention is illustrated with reference to the following examples.

Three catalysts for hydrocracking based on zeolites were used for the selective hydrocracking in light gasoline fractions existing η-paraffins used. Standard feeds were made in the inventive examples I to XIV and in Comparative Examples A to L used. Inventive examples © XV and XVI were used of feeds carried out during isomerization obtained from light paraffinic hydrocarbon fractions.

The catalyst used for hydrocracking was prepared as follows:

Catalytic converter 1

Repeated boiling with a fresh, 1.0 molar NH »NO _V solution reduced the alkali metal content of a synthetic erionite to less than 0.01 percent by weight. The resulting Nl 1 ^ ⁺ -Erionit was dried at 120 ⁰ C, for 3 hours calcined at 45O ⁰ C and impregnated with an aqueous nickel nitrate solution. After drying at 120 ⁰ C and 3 hours CaI

Zinieren at 500 C a catalyst with 2.3 weight percent nickel on an H ⁺ erionite was obtained.

209836/1119

Catalyst 2

This catalyst was prepared in the same way as catalyst 1, with the exception of the impregnation, which is used in this one Case was carried out with an aqueous Pt (NtU ^ CIg solution. A catalyst containing 0.2 percent by weight of platinum on H -Erionite was obtained.

Kata lys ator

Starting from a zeolite T, a catalyst was used with the method described for the preparation of catalyst 1 a nickel content of 2.1 percent by weight on an H zeolite T. Catalyst 3 became the same by mixing Amounts by weight of this catalyst (2.1 weight percent nickel on an H zeolite T) with catalyst 1 (2.3 percent by weight Ni on an H erionite).

The platinum containing catalyst was reduced in its Form and the nickel-containing catalysts in their sulphidic form Shape used. The conversion of the nickel-containing catalysts into their sulfidic foimi was carried out by adding of 0.015 percent by weight of sulfur as t-butylnnercaptaii for feed solution during the first 50 hours of the hydrocracking attempts causes. The platinum-containing catalysts were converted into their reduced form by the catalysts before the hydrocracking attempts in a Viasserstoff current at a temperature of 400 C and a pressure of 17 kg / cm ~ 10 hours.

20983S / 1119

All hydrocracking experiments are carried out at a pressure of 17 kg / cm and a hydrogen: feed molar ratio of 80: 1. In the catalyst containing platinum "The temperature was 375 ° C; the tests were carried out using a nickel-containing catalyst vmrden made at 39Ö ° C. In experiments I to XIV according to the invention and comparative experiments A to L

/ Air flow velocity /

the used / fluctuated between 0.5 and

-1 -1

8 liters χ 1 χ hour and was sized to be about 80 percent by volume of the n-Cg paraffins were converted. at experiments XV and XVI according to the invention have a spatial

-1 -1

flow rate of 21 liters χ 1 χ hour used.

The results of the experiments are zusammeiige- in Table A and ^B: handled.

209835/1119

Table A.

Example catalyst no. gate no.

Composition, vol.5c

"4

^; 5 ⁿ - ^C 5

Volume-

iC. Cr fraction ratio in üer ^ _feed-z ^ ^ _{ung STiei}

in

I. 2 II 2 III 2 20983S / IV
V.
VI CM CM CM «Ο VII
VIII CM CM IX 3 X 3 XI 1 XII 1

Granting - '-

Product 11.3

Addition

Product 10.8

Feed - 21.0

Product 9.0 21.4

Feed - 21.0

Product 9.2 20.7

Feed - 14.0

■ Product 15.2 13.8

Feed - 14.0

Product 16.1 14.5

Too much - 42.0

Product 13.3 41.5

Funding - 42.0

Product 13.1 42.0

Addition - 7.0

Product 18.2 7.3

Addition - 7.0

Product 17.9 6.8

Feed - 28.0

Product 15.9 28.4

Funding - 28.0

Product 16.2 27.9

87.5 86.3

87.5 86.7

63.5 62.9

63.5 63.1

64.0 64.2

64.0 62.8

Js ? J

33.1

33.3 32.7

72.0 70.3

72.0 71.1

52.5

12.5 2.4

12.5 2.5

6.5 1.3

6.5

16.0 3.2

2.9

6.7 1.3

6.7 1.3

18.0 3.6

18.0 3.7

7.5 1.5

7.5 1.4

100.0 100.0 70.0 70.0 80.0 80.0 40.0 40.0 90.0 90.0 60.0 60.0

7.0 • 7.0 O
r 9.8 9.8 4.0 ro 4.0 O
co 5.0 cn 5.0. 4.0 4.0 7.0 7.0

Table A - continued - 21 -

Example feed fulfills octane increase the loss of output loss of yield at no. The "requirement 'number - octane number for the C ^ fraction per add-65y> 2x + 80 C ⁺ fraction, acquisition unit of octane ° VoI- # number, Vol. -% _

¹ 7S7 42 113 ■ 2.7

TT J

¹¹ 884 54 108 2.0

TTT J

81.2 3.1 9 _? 0 2.9

Xv οι α / ι ο oo 2 3

7 '■ c
/ τ, ^
7S, 7 ₅ ; 11.3 83.0
88.4 3, 10.8 78.1
81.2 ₄ ; 9 _? 0 87.6
91.6. • 5, 9/2 70.1.
75.8 8th, 15.2 82.9
90.9 k ~ 16.1 78.9
83.1 4, 13.3 82.3
86.9 6, 13.1 68.4
74.6 ₇ ; 18.2 75.6
83.3 4, 17.9 77.9
82.8 ■ 6 ~ 15.9 83.1
89.1 2 16.2 4th 1 ο 7th 0 ₂ 6th 2 7 · 9 0

κ, ^V ■ - 75.8 '5.7 15.2 2.7

<ο VI

σι VII

2.0 ■ yes

. 3.2

α — Λ -ί ο

- VIII oc'n /. ί; λ -κ λ 2 8

IX η ι, ζ. cn -loo 29

X Q-3 ^ η Π. ΑΠ Ω 2 3 ^ * ^

XI DOO / ι η 'Ίκα 32 - ·

209835/1119

Example catalyst no. gate no.

Table A - continued

- 22 -

Composition, yo

Volume ratio

iC> rx-Qr C6 fraction 'in ~ ^s ° - ^c ß / ⁿ - ^ f ^{in the} 6 dor feed (χ) feed

XIII 1 XIV 1 A. 2 B. 2 C. 2 D. 2 E. 2 F. 2 G 1 H 1 J 1 K 1 L. 1

Feed
product 19.6 42.0
41.6 18.0
3.6 33.3
33.6 6.7
1.6 40.0 Feed
product 19.7 42.0
42.1 18.0
3.8 33.3
32.9 6.7
1.5 40.0 Feed
product 37.7 7.0
7.2 3.0
1.8 45.0
44.3 45.0
9.0 90.0 Too ei surig
product 37.2 7.0
7.3 3.0
2.0 45.0
44.7. 45.0
8.8 ■ 90.0 Subsidy
product 11.7 63.0
63.5 27.0
16.2 8.6 '
8.4 1.4
0.2 .10.0 Grant
product 13.9 63.0
62.1 27.0
15.8 8.6
■ 8.7 1.4
0.3 10.0 Feed
product 11.9 56.0
55.1 24.0
A h I, 17.8
18.2. 2.2
0.4 20.0 Feed
product 11.4 56.0
56.1 24.0
14.5 17.8
17.7 2.2
0.3 20.0 Feed
product 27.7 14.0
13.7 6.0
1.2 53.3
52.1 26.7
5.3 80.0 Feed
product 26 ~ 6 14.0
14.1 6.0
1.1 53.3
52.7 26.7
5.5 80.0 Feed
product 29.5 49.0
47.2 21.0
4.2 15.0
16.1 15.0
3.0 30.0 Addition
product 28.3 49.0
49.2 21.0
4.4 15.0
14.8 15.0
3.3 30.0 Snowfall
product 22.6 56.0
55.4 24.0
4.6 17.1
16.8 2.9
0.6 ■ 20.0

5.0 5.0 1.0 1.0 6.0 6.0 8.1 8.1 2.0 2.0 1.0 1.0 5.9

Table ^ A _{a i} - continued

Example feed fulfills octane increase the loss of output

No. the requirement number octane number prey at the

65y \ 2x + 80 C ^ fraction,

; . ^ Vol-fl

- 23 -

Loss of yield for the Cc ⁺ fraction per unit of increase in the octane number,% by volume _

co
to
cn

XIII
XIV
A.
B.
C.
D.
Ξ
F.
G
H
J
K
L.

Yes
there

no
no

there

there

no

no

no

no

there

80.6
87.1 . β'5 83.9
91.4 7 ~ 5 59.6
74.3 14.7 61.9
77.9 16.0 82.3
85.5 3.2 83.6
87.0 3 ~ 4 81.6
84.8 3Γ2 82.5
85.3 3 ~ 3 65.7
75.2 9 ~, 5 73.7
86.0 12.3 76-9
87.8 10.9 76.2
86.7 10.5 81.4
87.5 6 ~ 1

19.6 19.7 37.7 37.2 11.7 13.1 11.9 11.4 27.7 26 ~ 6 29.5 28.3 22.6 3.0

2.3 • 3I7 3Γ7 3 ~ 7 3I5

2 ~, 9

2.2

2.7 2.7 3.7

NJ O CD

- 24 Table B

Example no. Catalyst no.

Composition, ',% by volume C.
C-

C ₁₊ C ₂

i-c

nC ₆

C / fraction in the feed sung (x)

Cy ⁺ paraffins

Volume ratio i-Cg / nin the feed (y) Feed-in fulfills the requirement 65y ^ 2 x- + 80 Octane number

Increase in the number of OKI

Loss of yield of (^ + - fraction, vol ~%

Loss of yield of C5 ⁺ fraction per unit increase in octane number, VoI

XV

XVI

Feed product Feed product sung sung 1.2 3.1 - 10.6 - 10.9 - 1.8 - 4.0 31.7 32.1 32.0 31.6 19.6 11.2 20.9 13.2 .35.7 34.9 34.9 33.5 8.9. 3.9 8.8 0.8 44.6 - 43.7 - 4.2 4.3 3.3 3.0 4.0 - 4.0 - there - there - 77.1 ■ 81.3 77.4 83.3 - 4.2 _ 5.9

13.6

3.2

18.0

The results of the experiment listed in Tables A and B give rise to the following remarks.

In all examples, the starting material used was a feed containing more than 85 percent by volume of paraffins having 5 or 6 carbon atoms and less than 5 percent by volume of aromatics. In Examples I to XVI according to the invention, the feed also met the three requirements:> / 25, y > / 2 and 65y »2 χ + 80.

20983S / 1119

The comparative examples A Ms L were carried out with a feed which either did not meet one or more of the above requirements (for A and B y = 1, and the requirement 65y> 2 χ + 80 is not met; for C and D is χ = 10; for E and F is χ = 20; for G and H the requirement 65y> 2 χ + 80 is not fulfilled; for J and K y = 1, and the requirement 65y.> 2 χ + 80 not fulfilled; for L = χ L, χ = 20).

Examples I to XVI according to the invention met the criteria

_{It was found that the loss of the yield of the C 1} - fraction is less than 25 percent by volume and the loss of the yield of the C 1 - fraction

per unit increase in octane number less than 2.5 percent by volume amounts to.

In Comparative Examples A to L, at least one of the above criteria is not met (for A and B, the loss in yield of the C, - ⁺ ~ fraction is 37.7 and 37.2 percent by volume; for C and D, the loss is an Yield for the Cf- fraction per unit increase in octane number is 3.7 percent by volume; for E and F, the loss in yield for the Cf- fraction per unit increase in octane number is 3.7 and 3.5 percent by volume; for G and H, respectively the loss of yield for the CV fraction is 27.7 and 26.6 percent by volume; for J and K the loss of yield for the C, - ⁺ fraction is 29.5 and * 28.3 percent by volume; for L, the loss in yield for the Cc ⁺ fraction is 22.6 percent by volume and the loss in yield for the Cc ⁺ fraction per unit increase in octane number is 3.7 percent by volume).

209835/111 "

2206415

In other series of experiments, the method was preferred according to one used embodiment of the invention applied to three light paraffinic hydrocarbon fractions, obtained as distillate fractions from the distillation of crude oils carried out under atmospheric pressure was. The procedure followed procedures I, III and V. For comparison, the three light paraffinic Hydrocarbon fractions also with the help of isomerization and selective hydrocracking, but without separating the iso-Cr paraffins. Each of the attempts were made twice performed for the first time under such conditions the hydrocracking that about 40 percent of the n-pentane present in the feed for the hydrocracking and about 80 percent of the containing η-hexane, and the second Sometimes under such conditions box dor hydrocracking that about 80 percent of that contained in the feed for hydrocracking n-pentane and about 80 percent of the n-hexane contained were converted. The preparation of the catalysts used is described below.

Catalyst 4 ( isomerization catalyst)

Repeated boiling with a fresh 1.0 molar NH ^ NO, solution reduced the alkali metal content of a synthetic mordenite to less than 0.01 percent by weight.

The thus obtained NH ^ ⁺ -Mordenite was dried at 120 ⁰ C , at

45O ⁰ C for 3 hours calcined and impregnated with an aqueous Pt (NH ₇₅ I ^ Clp solution. After drying at 120 ⁰ C and.

3 hours of calcination at 500 ⁰ C was obtained a catalyst containing 0.3 weight percent platinum on a H ⁺ mordenite.

209835/1119

Catalyst 5 (hydro splitting catalyst)

Starting from a synthetic erionite and using the same procedure as described in "Catalyst 4, a catalyst was prepared with 0.2 weight percent platinum on an H -ordenite.

Catalytic converter 6 ( hydrolysis catalytic converter)

The starting material used to make this catalyst was zeolite KSO1. The catalyst was produced in the same way as catalyst 4, with the exception of the impregnation, which in this case was carried out with an aqueous Ni (NO ₇ ) p solution. A catalyst with 2.0 percent by weight of lap on the ϊΓ -zeolite KSOI was obtained.

The isomerization catalyst (Catalyst 4) was used in its: reduced form and the hydrocracking catalysts (Catalysts 5 and 6) in their sulfidic form. Catalyst 4 was converted into its reduced form by reducing the catalyst for ^{10 hours at a temperature of 400 °} C. and a pressure of 17 kg / cm in a stream of hydrogen before the experiments. Catalysts 5 and 6 were converted into their sulfidic form by adding 0.015 percent by weight of sulfur as t-butyl mercaptan to the feed during the first 50 hours of the hydrocracking experiment.

All isomerization attempts were made with the 0.3 weight percent platinum on an H -ordenite containing catalyst (Catalyst 4) at a temperature of 256 ° C, a pressure of 28 kg / cm, a space flow rate of one liter Feed per liter of catalyst per hour and one mol

209838/1119

- 28 ratio hydrogen: feed of 2.5: 1 carried out.

The hydro cleavage experiments with the} 0.2 percent by weight platinum on a ^{catalyst containing H +} erionite (catalyst 5) were carried out at a temperature of 400 ° C., a pressure of 35 kg / cm, a molar ratio of hydrogen: feed of

/ Room flow speed / 8.0: 1 and one "/ per hour from 0.5 up to

-1 -1

4 liters χ 1 χ hour made, so that about 40 percent of the η-Ηeptane present in the feed for the hydrocracking and about 80 percent of the η-hexane present was converted.

The hydrocracking tests with the catalyst containing 2.0 percent by weight of nickel on the H ⁺ zeolite KS01 (catalyst 6) were carried out at a temperature of 385 ° C., a pressure of 35 kg / cm '", a hydrogen: feed molar ratio of 0.0 : 1 and a space & flow velocity of 0.5 up to

- 1 - 1
4 liters χ 1 χ hour carried out, so that about 80 percent of the n-pentane present in the feed for the hydrocracking and about 80 percent of the η-hexane present were converted.

The compositions and octane numbers of these as feeds The three light gasoline fractions used are shown in Table C. Tables D and E show the results of the tests in which the light gasoline fractions with the help of Isomerization and selective hydrocracking, but without separation of the iso-Cc-paraffins, were converted »Tables F and G show the results of the tests in which the light »gasoline fractions according to the invention using the process

209838/1119

sequences I, III and V have been converted. Tables D and F show the results of experiments under hydrocracking conditions where about 40 percent of that in the hydrocracking feed existing n-pentane and about 80 percent of the η-hexane contained therein were converted. Tables E and G show the results of tests under hydrocracking conditions, • in which about 80 percent of the n-pentane contained in the feed for the hydrocracking and about 80 percent of the ri-hexane contained therein were converted. The ones in the tables The octane numbers listed are the octane numbers of unleaded gasoline and were determined by the research method.

Table_C

Composition and octane numbers of light paraffinic hydrocarbon fractions used as feeds

Feed 1 2_ 3.

CV paraffins, weight percent 25 Iso-CV paraffins, weight percent 10

CV / Cy cyclic hydrocarbons, _1Q ^ percent by weight

Weight ratio CV / C ^ paraffins 0.4 Octane number 61.0

50 4th 75 • 8th 20th 9 30th 5 10 5 1, 3, 69 74,

209835/1119

83, 2 84, 4th 85 5 n £ ² ' 1 - 83, 2 83, ο, 8th 1, 2 1, 5

- 30 -

Table D.

Conversion with the help of isomerization and selective hydrocracking, but without separating the iso-C, paraffins (conversion of the n-Cc and n-C, paraffins during selective hydrocracking: 40 percent and 80 percent).

Feed

Octane number of the C ₁ - fraction

Yield of Cp- fraction, based on on fresh feed, weight percent

Loss of yield in the Cj- fraction per unit increase in octane number, percent by weight

TableJS

Conversion with the help of isomerization and selective hydrocracking, but without separating the iso-Cp- ~ paraffins (conversion of the n-Cp- and n-C ^ -paraffins during the selective hydro split: 80 percent or 80 percent)

Octane number of the Cc ⁺ fraction. 84.2 86.5 88.5

Yield of C ₁ - fraction, based on 78 6 76 2 73 1 on fresh feed, weight percentage / '''

Loss of yield in the Cr- fraction per unit increase in the 0.9 1.4 1.9 octane number, percent by weight

209335/1119

Table F , - 31 -

Conversion according to the invention (conversion of the n-C, - and n-Cg paraffins, during the selective

Hydro splitting: 40 percent or SO percent)

Feed-in 1 2, _____. _. _,

Procedure I III V I III V I III V

Octane number of the Cc ⁺ fraction 83.9 84.2 84, β. 35.8 87.0 87.5 87.1 89.2 89.6

, Yield of C _R ⁺ fraction, based on 83.4 85.1 85.0 85.6 89.0 89.3 87.5 92.6 9.2.9 ^w based on fresh addition * Cb weight percent

to loss of yield in the C ₅ ⁺ - 0.7 0.6 0.6 0.9 0.6 0.6 1.0 0.5 0.4 fraction per increase unit
^ω h

the octane number, weight percent

Table G.

Conversion according to the invention (conversion of the n-C = - and n-Cg paraffins during the selective

Hydro splitting: 80 percent or 80 percent)

Feed _: ________ 1 2. 3

Procedure -I III V I III V I III V

Octane number of the C ₅ ⁺ fraction 84.5 84.7 84.7 87.1 87.6 87.6 89.1 89.3 89.8

Yield of C ₅ ⁺ fraction based on 81.2 84.2 84.7 81.4 88.6 89.0 80.9 '92, 0.92.4K

on fresh feed, percent by weight. . ΓΟ

Loss of yield with the C ₅ ⁺ - 0.8 0.7 * 0.6 1.1 0.6 0.6 1.3 0.5 0 »5_n

Fraction per increase unit. . the octane number, weight percent

The results of the tests listed in Tables D to G * search give rise to the following remarks.

If the results obtained in the conversion of light gasoline fractions with the aid of isomerization and selective hydrocracking, but without separation of the iso-C (- paraffins, are compared with the results obtained in the conversion according to the invention using process sequence I, it becomes apparent that with the process according to the invention a C _R fraction with a higher octane number and in higher yield is obtained.

If you think about using the corporate process compares the results obtained according to process sequence I with the nr.ch process sequence III or V. results obtained, it can be seen that both with process sequence III as with process sequence V, a C, - fraction with a higher octane number and is maintained in higher yield as when using process sequence I.

In the conversion without separation of the iso-C ^ paraffins, the loss in yield of the C _r fraction per unit increase in octane number increases with the increase in the weight ratio of Cr to C / paraffins in the feed. When using the process according to the invention according to process sequence I, this loss of yield of the CV fraction per unit increase in octane number decreases with the increase in the weight ratio of Cc to Cg paraffins in the feed. When using the process according to the invention according to process sequences III and V, there is even a reduction in the loss of yield

209838/1119

of the Cp- ⁺ fraction per unit increase in octane number, provided the weight ratio of C ₁ - to Cg paraffins in the feed increases.

209835/1119

Claims (30)

Claims 1. Method for increasing the octane number of n-paraffins containing Light gasoline fractions, characterized in that that a light gasoline fraction containing a) more than 85 percent by volume of paraffins with 5 or 6 carbon atoms, b) less than 5 volume percent aromatics and / Volur netiv e rhaitnis von c) χ volume percent of Cg ~ paraffins with a "" ~ J iso-to-noraal connections of y ,. where χ> -25, y>, 2 and the relation 65y >, 2 x + 80 holds
a selective hydrolysis with respect to η-paraffins will be requested. 2. The method according to claim 1, characterized in that the Light gasoline fraction contains more than 90 percent by volume of paraffins with or 6 carbon atoms. 3. The method according to claim 1 or 2, characterized in that that the light gasoline fraction contains less than 2 percent by volume of aromatics. 4. The method according to claim 1 to 3 »characterized in that the light gasoline fraction contains χ percent by volume of Cg paraffins with a ratio of iso-to normal compounds of y, where χ > / 40. 5. The method according to claim 1 to 4, characterized in that the light gasoline fraction contains χ percent by volume of C ^ paraffins with a ratio of iso-to normal compounds of y, where y > / 4. 209835/1119 "- 35 - 6. The method according to claim 1 Ms 5, characterized in that the light gasoline fraction C - contains paraffins with a ratio of iso-to normal compounds of > / 1. 7. The method according to claim 1 to 6, characterized in that the final boiling point of the light gasoline fraction is lower than 75 ° C. 8. The method according to claim 1 to 7, characterized in that that the light gasoline fraction contains sulfur, in particular 0.0002 up to 0.001 percent by weight of sulfur. 9. The method according to claim 1 to 8, characterized in that the light gasoline fraction by isomerization of a light paraffinic hydrocarbon fraction containing η-paraffins and C, -paraffins has been obtained. 10. The method according to claim 9, characterized in that the light gasoline fraction from a paraffinic hydrocarbon fraction has been obtained from the before and after isomerization at least some of the iso-CV paraffins are separated off became. 11. The method according to claim 10, characterized in that at least some of the separated iso-C ^ paraffins in the dor selective hydrocracking product is added. 12. The method according to claim 10 and 11, characterized in that that the light gasoline fraction has been obtained from a light paraffinic hydrocarbon fraction which is above 10% by weight and especially over 20 percent by weight Contains CV paraffins. 20983S / 1119 13. The method according to claim 10 to 12, characterized in that the light gasoline fraction from a light paraffinic Hydrocarbon fraction has been obtained, the GV paraffins mi (t a volume ratio of iso-to normal compounds which is lower than 4 and in particular lower than 2. '\ l \. Process according to Claims 10 to 13, characterized in that the light gasoline fraction has been obtained from a light paraffinic hydrocarbon fraction "from which before or after the isomerization" over 75 percent and in particular over 85 percent of the iso-C _r - Paraffins were separated. 15. The method according to claim 10 to 14, characterized in that, that the light gasoline fraction has been obtained from a light paraffinic hydrocarbon fraction from which before or after isomerization, an iso-Cc paraffin fraction is separated off which contains over 85 percent by weight and in particular over 95 percent by weight iso-C ^ paraffin. 16. The method according to claim 10 to 15, characterized in that the light gasoline fraction from a light paraffinic Hydrocarbon fraction has been obtained in the presence polymerized by hydrogen and a catalyst containing one or more Group VIII metals of the periodic * one
Systems on / zeolite with a pore diameter of between 6 and contains 15 % as carrier material. 209835/1119 17. The method according to claim 16, characterized in that the light gasoline fraction has been obtained from a light paraffinic coal fraction which has been isomerized in the presence of a catalyst based on mordenite, in particular a platinum catalyst on a mordenite carrier material. 18. The method according to claim 16 or 17, characterized in that the light gasoline fraction has been obtained from a light paraffinic hydrocarbon fraction, which at a temperature of 10O ⁰ C up to 400 ° C, a pressure of 5 up to 50 kg / cm, a Space flow rate of 0.5 to 10 liters of feed per liter of catalyst per hour and a molar ratio "hydrogen: feed of 0.5: 1 to 10: 1 was iaomerized. 19. The method according to claim 1 to 18, characterized in that the selective hydrocleavage of the light berizine fraction in its essence one, one or more metals of group Ib, Hb, Via, VIIa and / or VIII of the periodic table on a porous Carrier material with a uniform pore diameter of between 4 and 6 & containing catalyst carried out will. 20. The method according to claim 19, characterized in that the porous carrier material with a uniform pore diameter of between 4 and 6 Å is a zeolite . 21. The method according to claim 20, characterized in that the carrier material used for the catalyst with a zeolite 209835/1119 an alkali metal content of less than 2 percent by weight, in particular is less than 0.1 percent by weight. 22. The method according to claim 20 and 21, characterized in that the hydrocracking is carried out on a catalyst is, the per 100 Gewi disfigured carrier material 0.05 to 5 parts by weight and in particular 0.1 to 2 parts by weight of a Group VIII noble metal, in particular platinum or palladium, is retained. 23. The method according to claim 19 to 21, characterized in that that the hydrocracking is carried out on a catalyst, 0.1 to 35 "parts by weight of a base metal or a combination of base metal per 100 parts by weight of support material Contains metals. 24. The method according to claim 23, characterized in that the hydrocracking is carried out on a catalyst which, per 100 parts by weight of support material, contains a combination of 0.5 up to 20 parts by weight. and especially 1 to 10 parts by weight of a base metal of Group VIII and 0.1 to 30 parts by weight, in particular 2 to 20 parts by weight of a metal from group VIa and / or VIIa, in particular a combination of Nickel and / or cobalt with tungsten and / or molybdenum and / or Contains rhenium. 25. The method according to claim 19 to 21, characterized in that the hydrocracking is carried out over a catalyst which contains 0.1 to 0.35 parts by weight and in particular 1 to 15 parts by weight of nickel per 100 parts by weight of support material. 209835/1119 26. The method according to claim 23 to 25, characterized in that that the catalyst is used in its sulfidic form. 27. The method according to claim 1 to 26, characterized in that the selective hydrocracking at a temperature of 250 to 60O ⁰ C, a pressure of'5 to 100 kg / cm, a space flow rate of 0.20 to 20 kg of hydrocarbon feed per kg of catalyst per hour and a hydrogen to hydrocarbon feed molar ratio of 1: 1 to 50: 1. 28. The method according to claim 1 to 27, characterized in that it is carried out in a system that consists of bus following units arranged in the order specified? a first distillation zone, an isornization zone, a zone for selective hydrocracking and a second distillation zone, the iso - C _r -paraffins; be separated from the light gasoline fraction in the first distillation zone, the Cj - paraffins from the product obtained in the hydrogenative cleavage are separated in the second distillation zone and the iso-Cr paraffins separated in the first distillation zone either with the bottom product of the second · The distillation zone can be blended or withdrawn as a separate product stream. 29. The method according to claim 1 to 27, characterized in that it is carried out in a system consisting of the following, consists of units arranged in the order given; a first distillation zone, an isomerization zone, 209835/1 1 19 a second distillation zone, a zone for selective hydrocracking and a third distillation zone, the iso-C _c paraffins being separated in the first distillation zone from a mixture of light gasoline fraction and the C, r ~ paraffin return stream, the C, - "" -Paraffins are separated from the isomerized paraffins in a second distillation zone and returned to the first distillation zone, the (^ "- paraffins are separated from the hydrocracking product in a third distillation zone and the iso-C ^""paraffins separated in the first distillation zone either be blended with the product from the hydrocracking which is used as the feed for the third distillation zone or separated into (^ "- paraffins and iso-Ct-paraffins in a separate distillation zone, after which the latter are withdrawn as a separate product stream. 30. The method according to claim 1 to 27, characterized in that it is carried out in a plant which consists of the following units arranged in the order given: an isomerization zone, a first distillation zone, a second distillation zone, a zone for selective hydrocracking and a third distillation zone, wherein old; The feed for the isomerization zone is a mixture of the light gasoline fraction and the n-pentane return stream, the iso-Cc-paraffins are separated from the isomerized paraffins in the first distillation zone, n-pentane is separated from the bottom product of the first distillation zone in the second distillation zone and added again the isomerization zone is returned, the C (- paraffins from the product of 209836/1119 Hydrocleavage are separated in the third distillation zone and the separated in the first distillation zone iso-C (- "~ -paraffins either with the as feed for the third distillation zone serving product of the hydrocracking blended or in a separate distillation zone in (^ "-Paraffins and Cc" -paraffins are separated, after which the the latter can be withdrawn as a separate product stream. 209836/1119 Blank page