BE440171A - - Google Patents

Description

       

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  Company: UNIVERSAL OIL 9RogQcTs, aolJo ± NY. ,,,
The invention relates to the processing of hydrocarbon oils and in particular to the treatment of gasoline hydrocarbons containing olefins, such as, for example, cracking gasolines, and relatively saturated hydrocarbon oils, and has for object the production of oil. gasoline with a high octane number and relatively low olefin content.



   Cracking essences produced by purely thermal or thermo-catalytic cracking operations contain varying percentages of olefinic hydrocarbons, depending on the type of product that has undergone the cracking and the severity of the cracking conditions, the temperatures. high and low pressures tending to give percentages of oil

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 relatively stronger fine.

   While these olefin-containing cracking gasolines and the like are ideally suited for ordinary automobile engines, especially when stabilized against weathering by inhibitors, the conditions that must be met by fuels used in motor vehicles. High-compression aircraft engines are much more stringent, for they must not have the slightest tendency to form gum, or to clog the supply pipes, while at the same time their power anti-knock must be considerable, so that the engines develop with certainty the maximum of their power.

   These stringent conditions can hardly be satisfied except by iso-paraffinic hydrocarbons and some aromatic and naphthenic hydrocarbons, whose solidification points of hydrocarbons alone or in mixture with other hydrocarbons are low enough to prevent them. to solidify at the low temperatures encountered at high altitudes. A particular subject of the invention is a process for the preparation of fuels for substantially saturated engines, highly anti-knock and suitable for use in aircraft engines.



   According to the invention, high octane gasoline with a relatively low olefin content is produced by a process which comprises adding a relatively saturated hydrocarbon oil to gasoline hydrocarbons containing olefins. and bringing the mixed hydrocarbon oils into contact with a cracking catalyst at a temperature, under a pressure and for a contact time liable to cause a significant decrease.
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 of the olefin content of petroleum hydrocarbons conzt gt /Affi.//1'Ii holding olefins / undergoing treatment4

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More particularly, the invention consists of a process, by which relatively saturated hydrocarbon oils are mixed,

   in particular relatively heavy straight-run distillation fractions or the like, with boiling points in the range of those of kerosene or gas oil, with gasoline hydrocarbons containing olefins, such as gasoline-containing distillation products from cracking operations, and this mixture is treated under conditions of temperature, pressure and contact time, in the presence of a cracking catalyst, intended not only to cause decomposition the heaviest elements of the mixture to obtain gasoline, but also the hydrogenation of the olefins existing in the original mixture and those produced by the catalytic treatment,

   so as to form a saturated gasoline consisting essentially of para $ --finic and aromatic hydrocarbons only,
In the practical embodiment of the invention which is preferred, the mixture of relatively saturated hydrocarbon oil with gasoline hydrocarbons containing olefins is brought into contact with catalyst particles obtained by calcination of a complex mixture or assembly, substantially free of alkali metal, of precipitated hydrated silica with precipitated hydrated alumina and / or with precipitated hydrated zirconia, and this contact is effected at a temperature transformation greater than 260 C and less than 482 C,

   preferably between 315 ° and 425 C under a pressure between atmospheric pressure and 14 atmospheres or more and with a coefficient of

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 Relatively low hourly flow, preferably between 0.5 and 5.



   Now, it has been discovered that when bringing mixtures of olefinic gasolines and gas oil fractions from crude oil, for example, into contact with suitably chosen catalysts under the above conditions, several simultaneous reactions occur concurrently between the hydrocarbons, so that not only the olefins existing in the cracking gasoline undergo hydrogenation to form the corresponding paraffins, but also the gasoline olefins produced by the gas oil cracking undergo also hydrogenation. It seems that certain saturated elements of the gas oils used, such as naphthenes for example, undergo dehydrogenation supplying the hydrogen necessary for the hydrogenation of olefins to form paraffins,

   so that not only aromatics from naphthenes are obtained, but also paraffins from olefins, the mixture of these two types of hydrocarbons having a relatively strong anti-knock power and the additional advantage of be relatively free from olefinic and similar reacting hydrocarbons.

   Although the invention is not limited to the theory set out above, it can be considered that the following equation explains in principle the general mechanism of the reaction:
AT
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 Cyclohexane hexene benzene hexane
It is evident that this reaction is purely schematic and is accompanied by other less sharply defined and more complex reactions, involving the breaking of carbon-to-carbon bonds, isomerization,

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 recombination of radicals, etc., In the above equation. cyclo-hexane represents the naphthenic hydrocarbons contained in lamp oils or gasols, while hexene represents an olefinic element of a low boiling point distillation product of the nature of gasoline.

   Although tests have indicated that the hydrogen resulting from the saturation of olefins comes mainly from the naphthenic elements of gas oil and similar fractions, there is no doubt that a certain amount of hydrogen comes from the dehydrogenation and cyclization of various paraffinic elements originally existing in or from the hydrocarbon mixture and the subsequent dehydrogenation of the cyclic compounds formed.

   However, it is uniformly observed as a final result that the gasolines obtained by treating mixtures of hydrocarbons of the type described consist mainly of paraffinic and aromatic hydrocarbons, as indicated by the relatively low bromine numbers, which are given later along with other digital data.



   The operation requires the use of a relatively active catalytic substance, described below, at temperatures significantly lower than the ordinary cracking temperature ranges of purely thermal or thermo-catalytic cracking operations and moderately long contact times with the catalyst.



  The reactions are further favored by the increase in pressure which facilitates the secondary hydrogenation reactions.



   While alumina hydrosilicates, such as acid-treated clays and the like, can be generally employed, the catalysts are preferably chosen for use in the process.

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 of the invention, have a very particular character and require to be prepared by a very precise process.



   According to the description of the preparation of the preferably chosen catalysts, given below, it is possible to combine a precipitated alumina hydrogel and / or a zirconia hydrogel with a silica hydrogel, then the compound product can be washed and dried. , mold it into particles and calcine it to obtain a catalytic mass. However, the various catalysts which can be so prepared do not necessarily give equivalent results.



   In the following description, the expressions masses of “silica-alumina”, “silica-zirconia” and “silica-aluminezirconia” are used in their broadest sense. Since the solid state from the chemical point of view is not yet fully known, it is not possible to indicate the structure of all solid bodies. All that can be said precisely about these masses is that they contain silicon, oxygen and aluminum and / or zirconia. However, in general, all these elements individually have a more or less weak catalytic activity, but in the form of agglomeration their activity is strong.

   This activity is not an add-on function, since it is relatively constant for proportions of the elements varying over a considerable range, whether they are molecular proportions or molecular fractions. None of these elements can be determined as being that for which the other elements are accelerators, according to the usual terminology, nor as being the support, while the others are the catalyst proper,

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To prepare the catalysts to be preferably employed in the process of the invention, it is necessary to employ silica prepared by precipitation from a solution in the hydrogel state, in which or on which the alumina and / or zirconia are also deposited by precipitation in the form of hydrogels.

   The usual and most convenient method of preparing a satisfactory silica gel is to acidify an aqueous solution of sodium silicate by adding the necessary amount of hydrochloric acid.



  The excess of acid and the concentration of the solution in which the precipitation takes place determines the possible primary activity of the silica and its ability to enter into composition with the alumina and / or zirconia hydrogels to form a high activity catalyst. In general, the most active hydrated silica is obtained by adding only the quantity of acid sufficient for a gel to form in the sodium silicate, but the product formed at this time is quite gelatinous and is difficult to filter. In addition, the silica hydogel only coagulates incompletely at this time.



  By adding a moderate excess of acid, once the hydrogel is formed, the product retains its more favorable physical characteristics from the point of view of catalytic activity, while it is generally easier to filter and that the silica hydogel precipitates more completely. A hydrated silica which is satisfactory in the catalytic applications of the invention can be prepared by employing an excess of hydrochloric acid of up to 20%, but beyond this proportion the advantageous properties are lost.



  Once the silica gel has precipitated, it is preferably washed until it is essentially free of salts, using: several reagents capable of being replaced which will be

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 indicated below.



   According to a method of preparing the activated silica form, one can either boil the silica hydrogel, with the separately precipitated aluminum hydroxide and / or a zirconium hydroxide gel, which is added to the mixture. wet state to the silica suspension, either suspend the silica hydrogel in a solution of aluminum chloride and boil it with it, or treat the silica gel in the same way with an aqueous solution containing the salts of aluminum and zirconium.

   In each of these cases the final precipitate, which essentially contains hydrated silica and hydrated alumina and / or zirconia, is finally washed to remove almost all of the water soluble material and / dried at a temperature. of about 150 ° C, so as to form a fairly crumbly seed product, which can be ground and pelleted or sieved to form catalyst particles.

   As this product is calcined at a temperature in the approximate range of 540 to 820 C and is used at a temperature of the order of 260 to 4820, its water content decreases further until 'after a short service life, it is equal to about 2 to 3% by weight of the catalyst particles.



   According to one method of preparation, the necessary hydrogel of alumina or zirconia is preferably deposited, or a mixture
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 of these gels on a washed silica gel free from alkali metals by the addition of an alkaline precipitating agent, such as ammonium hydroxide, ammonium carbonate or ammonium sulphide to aqueous solutions of aluminum and / or zirconium salts, followed by an appropriate washing to remove impurities. Thalumina and / or zirconia hydrogels can

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 They can be precipitated from a solution in which the hydrated silica previously prepared and washed is suspended, this operation being followed by washing of the total complex precipitate.

   Likewise, the purified hydrated silica can be suspended in an aluminate solution, such as sodium aluminate, and the alumina precipitated by the addition of the aluminum salts, or necessary amounts. acid, followed by an appropriate wash. As an alternative, another method of preparing the desired catalysts consists in adding aluminum and / or zirconium salts to a solution of an alkali metal silicate to precipitate together a silica hydrogel with the aluminum hydrogels. - lead and / or zirconia and precipitate additional quantities of silica hydrogel by the addition of acid.

   The following equation represents one method of preparing a silica and alumina catalyst, this equation not taking into account the water of hydration:
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It is evident that the application of the reaction, represented by the preceding equation, is limited in molar proportions, so that this method of preparing a compound product may need to be. supplemented with additional precipitated hydrated silica to provide the desired ratio.



   A special and satisfactory process for preparing the silica and alumina catalysts employed in accordance with the invention is described below, but not with a view to limiting too strictly the true scope of the invention. By proceeding in the manner described and suitably selecting the reactants in a suitable state of purity, catalysts can be prepared which are substantially satisfactory.

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 in all cracking and hydrogen transport reactions of the type described.



   In finished catalysts prepared as above, the proportion by weight of silica to alumina and / or zirconia can vary within wide limits, for example from 30 to 0.1, although in normal complex catalyst products having maximum activity, based on the yields and quality of the gasoline obtained, the ratio of silica to oxide weights varies from 30 to 10, with the word "oxide" being used. to denote alumina and / or zirconia. These proportions vary markedly with the particular fractions which undergo the treatment and the degree of transformation found to be most advantageous in each particular case.



   It must be recognized that very little precise information is known about the mechanism of the increase in the activity of complex catalysts and it is not intended here to set out any definite reasons for the accelerated effect. the observed mutual operator of the various elements separately in the complexes of silica and alumina and / or zirconia prepared for the catalytic applications according to the invention. This may be a catalytic effect due to the juxtaposition of the elements of the catalyst and it. The oxide (alumina and / or zirconia) may be the most active catalyst and is very widely dispersed in and on the silica, so that its surface area is large.



   In the simplest sense of the invention, the saturated hydrocarbon oil serving as the hydrogen supplier can be mixed with the relatively unsaturated hydrocarbon fraction and subjected to the catalytic treatment in the presence of the hydrocarbons. preferably selected catalysts described above to provide a gasoline consisting primarily of paraffinic and aromatic hydrocarbons which

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 possess a relatively high octane number, a low potential gum content and a satisfactory receptivity for anti-knock compounds, which makes it possible, by the addition of relatively low proportions of tetraethyl lead, for example, to obtain a gasoline suitable for the gasoline. 'aviation.



   The mixture of oils can be preheated to a temperature suitable for the hydrogen transport reaction in contact with the preferably chosen catalyst, then the preheated vapors are passed over a stationary mass of catalytic particles contained in a cylinder chamber. - drric.

   However, it is generally better to pass the preheated vapors through a catalyst arranged in tubes of relatively small diameter forming multiple links between manifolds. because the installation thus arranged makes it possible to carry out outdoor heating in
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 Better conditions, if necessary, to maintain the desired reaction temperature for XIIO mle, and to absorb the heat given off during the alternating regeneration treatments, during which large quantities of heat are given off by the heat. oxidation of carbonaceous deposits on the catalyst.

   Although temperatures, which exist before the catalyst may be between 260 and 482 C, those in the approximate range of 372 to 425 C are preferable in most cases. The pressure can vary between a pressure substantially equal to atmospheric pressure and 14 atmospheres, but in some cases pressures up to about 70 atmospheres, for example, have been found to be advantageous. Hourly flow coefficients of between 0.5 and 5 have given good results, the hourly flow coefficients being the volume of oil charged per hour relative to the volume of catalyst contained in the reaction chamber.

   The relative proportions

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 tives of saturated hydrocarbon oil introduced into the operation to saturate the unsaturated gasoline hydrocarbons, contained in the fraction of hydrocarbon which undergoes the treatment, are obviously variable according to the degree of unsaturation of the oil. The oil undergoing the treatment and the proportion of hydrogen available in the saturated oil serving as the hydrogen supplier. Among the examples given below, Example 1 applies to the simplest meanings of the invention.



   The invention is not limited from the point of view of the source of fractions containing unsaturated hydrocarbons undergoing the treatment according to the invention and several important sources are the gasolines obtained from pyrolytic cracking, thermal reforming, and catalytic oracking. lytic more generally carried out at fairly high temperatures, as well as olefinic hydrocarbons from the polymerization of gaseous olefins.



   With regard to pyrolytic cracking, the gasoline fractions can originate from vapor phase cracking as well as high pressure thermal cracking, which is more generally carried out in practice.



   According to one method, for example, the oil is heated in a heating element to the temperature of the reaction and passed through a reaction chamber.



  The transformation products are separated in a separation chamber, from which a non-vaporized residue is removed and the vaporized products are passed through a fractionation tower. The product from the feed can be fed into the fractionation tower to aid in cooling and passed along with the underprocessed products to the heating element. The olefin-containing fractionated gasoline product from thermal oraoking exits at the top of the fractionation tower and then undergoes condensation and product separation.

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 gaseous.

   The temperature of the oil passing through the reaction chamber can be for example between 455 and 540 ° C and the pressure can be of the order of 14 to 41 atmospheres or more or less;
A common process for reforming or thermally forming straight run gasolines is to heat the oil in a properly constructed heating element so as to provide the desired contact time at a pressure between 41 and. 82 atmospheres or higher and at an outlet temperature of 482 to 566 C, then fractionating and separating the transformation products to obtain a gas fraction,

   a reforming gasoline containing olefins and often a small proportion of hydro-carbon product with a higher boiling point than the range of gasoline
Gasoline fractions with a high olefin content are also obtained by cracking in the presence of catalysts, such as the catalysts preferably employed in the process of the invention, by operating at temperatures higher than those which are chosen to be preference for the hydrogen transport reaction,

   which forms the main object of the description. The installation employed may consist of a heating element serving to vaporize the oil and bring it to approximately the temperature of the reaction and of several reaction chambers containing the catalyst arranged so that the operation may be carried out in a continuous fashion by treating the vapors in one or more chambers, while the other chambers may be being reactivated.

   The products of the transformation leaving this installation are separated and fractionated, so as to provide a gaseous fraction, a fraction of olefinic gasoline and heavier hydrocarbons, which can be subjected in part or in whole to a new treatment.

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 catalytic cracking, thereby to achieve maximum use of the product of the feed in the preparation of fractions with boiling points in the range of those of gasoline. The temperatures at which contact with the catalyst takes place may be approximately between 425 and 650 ° C.,

   and the pressure may be between atmospheric pressure and a pressure above atmospheric pressure of the order of 7 atmospheres or more * The hourly flow coefficient is more generally greater) that of the transport reaction of hydrogen.



   By the processes described above, gasoline fractions are obtained whose olefin content varies between wide limits of 20 to 70%, or more, or less, the proportion of unsaturated hydrocarbons depending on the process and the nature of the hydrocarbon oil undergoing the treatment.



  According to the enlarged scope of the invention, the aforementioned processes can be coordinated with advantage in the process according to the invention, so as to pass the unsaturated gasoline hydrocarbons in the hydrogen transport operation, in combination with a relatively saturated hydrocarbon oil, and to return the high boiling fractions, separated from the saturated gasoline product of the hydrogen transport reaction, to the cracking or cooling zone. primary reforming, to be used again for the production of gasoline fractions.



   In a typical embodiment of this combined operation, consisting of thermal cracking to prepare olefinic gasoline fractions, a thermal cracking treatment is subjected to a combined feed formed from a mixture of hydrocarbon oils. untreated and partially processed, as will be explained hereinafter, the vapor transformation products from this treatment are separated in a vapor separation zone.

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 fears,

   residual fractions with high boiling points and are brought to a first fractionation zone with the vapors possibly formed in the vapor separation zone * the transformation products are fractionated in the vapor state in the first fractionation zone in the state of admixture with the added hydrocarbon oil, forming the product of the operation charge, and thus separating the process vapors and the hy- drooarbon added in fractionated vapors with boiling points in the range of gasoline, and in hydrocarbons with higher boiling points, which are preferably separated in the first fractionation zone in selected combined loads, liquid, light and heavy,

   at least some of the higher boiling point hydrocarbons, preferably the heavy combined feed, are fed as a portion of the total combined feed to the thermal cracking treatment zone, the fractionated vapors are discharged from the first fractionation zone and brought to a catalytic transformation zone in contact with the cracking catalyst, operating under conditions suitable for providing low olefin gasoline.

   When the added hydrocarbon oil is a crude mineral oil containing gasoline or a similar hydrocarbon oil with a wide boiling point interval, the fractionated vapors leaving the first fractionation zone constitute a mixture of Relatively high olefin content gasoline hydrocarbons with gasoline hydrocarbons of a highly saturated nature.

   However, in some cases and in particular where the added hydrocarbon oil constituting the feed product contains little or no direct run gasoline type hydrocarbons, a selected light combined feed can be mixed. collected in the first fractionation zone with the fractionated vapors which leave this zone and one

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 then causes the mixture thus obtained to arrive in the zone of the catalytic transformation operation. In addition, the fractionated vapors leaving the first fractionation zone can be subjected to condensation and gas separation, and the distillation product thus obtained can be sent to the catalytic transformation zone.

   If desired, after separating from the transformation products leaving the catalytic transformation zone their disadvantageous high boiling point elements, these transformation products are fractionated in a second fraction zone, * mentally separated, in which the low olefin gasoline product separates as a vaporized fractionated product from the heavier partially processed hydrocarbons which are condensed as condensate reflux, this oondensation reflux is caused to occur, at less in part, in the thermal cracking treatment zone in the state of admixture with the aforementioned heavy combined feed from the first fractionation zone,

   while the low olefin gasoline product is condensed and collected in the vaporized fractionated product of the second fractionation zone.



   According to another embodiment, in which the thermal transformation treatment is combined with the catalytic transport of hydrogen, and which is particularly advantageous for the simultaneous transformation of weakly anti-knock gasoline and of oil fractions. higher boiling point hydrocarbons, thermal reforming of straight-run light hydrocarbon oil and thermal cracking of heavier hydrocarbon oil in a combined cracking treatment plant and of thermal reforming, the gasoline of thermal cracking and reforming thus obtained is mixed with a saturated hydrocarbon oil and the mixture is brought

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 thus obtained in contact with an oraoking catalyst,

   by operating under conditions such as to form transformation products containing significant proportions of gasoline with a high octane number and a low olefin content, the transformation products leaving the catalytic transformation zone are fractionated in order to separate the low olefin gasoline product of the heavier hydrocarbons existing in the transformation products, the low olefin gasoline product is collected and the heavier hydrocarbons are condensed and partially returned at least in the thermal cracking treatment zone.

   In order to apply this embodiment to the treatment of hydrocarbon oils having a large boiling point range, such as crude mineral oils, the hydrocarbon oil constituting the product of the feedstock can be subjected to a temperature. fractional distillation in a first fractionation zone to separate therefrom a light fraction consisting essentially of hydrocarbons having boiling points in the range of those of gasoline, an intermediate fraction consisting essentially of point hydrocarbons. boiling within the range of those of gas oil and a heavy fraction containing hydrocarbons with boiling points higher than those of the intermediate fraction,

   the heavy fraction is mixed with the condensation reflux fractions formed as will be explained below and the mixture is subjected to the thermal cracking treatment, at the same time the light fraction obtained is subjected to From fractional distillation in a separate reforming zone, to the thermal reforming process, the transformation products of the thermal cracking and reforming processes are mixed and separated in a zone for separating the vapors into residue elements. high boiling or non-vaporized and disadvantageous duels and vaporized transformation products that are

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 split into a second separate fractionation zone,

   the fractionated vapors, at boiling points within the range of those of gasoline and comprising gasoline which comes from the thermal cracking and reforming treatments, are taken out of this second fractionation zone and these vapors are mixed, preferably after condensation and separation of the uncondensed gases, with the intermediate fraction resulting from the fractional distillation, the mixture of the cracking distillation product and the direct distillation fraction thus obtained is subjected to a hot temperature. catalytic transformation by contact with the cracking catalyst, operating under conditions such as to form significant proportions of gasoline with a high octane number and a low olefin content, the products resulting from the vatalytic transformation are fractionated in a third fractionation zone,

   with or without intermediate separation of the possible disadvantageous elements with high boiling points existing in these products, the fractionated vapors with boiling points in the range of those of the third fractionation zone are removed from the third fractionation zone. gasoline and condensed to collect the high octane, low olefin gasoline product, while the hydrocarbons with boiling points higher than those of gasoline are condensed in the form of condensation reflux fractions in each of the second and third fractionation zones,

   in the vapors which undergo fractionation therein and the heat cracking treatment is subjected to at least portions of each of the condensation reflux fractions thus obtained with the heavy fraction from the fractional distillation.



   In a typical embodiment, which involves the combination of the relatively high temperature catalytic cracking with the catalytic transport treatment.

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 hydrogen at a relatively low cracking temperature, the hydrocarbon oil can be converted to a large extent into gasoline with a relatively high olefin content by contact with a cracking catalyst, in a high temperature cracking zone , the products leaving this zone are mixed with a saturated hydrocarbon oil, and the mixture of these oils is brought into a separate catalysis zone, in contact with the cracking catalyst,

   by operating under conditions such as to form gasoline substantially free of olefinic hydrocarbons, the approximately saturated gasoline thus obtained is collected and the higher boiling hydrocarbons resulting from the transformation are returned to the gasoline. catalyzation zone separated, at least in part, in the high temperature cracking zone.

   To apply this procedure in practice, the products leaving the high temperature cracking zone can be partially cooled, preferably by mixing them with saturated hydrocarbon oil and separated in a separation zone. vapors into a non-vaporized residue and vaporized transformation products free from disadvantageous high-boiling point elements, the vaporized transformation products are removed from the vapor separation zone and brought to the state. mixing with a saturated hydrocarbon oil having the character of a distillation product, in contact with the cracking catalyst in a separate catalysis zone at a relatively low cracking temperature,

   and converted therein to a product containing a substantial proportion of gasoline substantially free from olefinic hydrocarbons. In certain cases, it may be advantageous to condense the transformation products in the vapor state leaving the vapor separation zone and to separate the non-condensable gases therefrom, in this case by heating the distillation product to temperature suitable for

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 hydrogen transport reactions. In all cases, the saturated hydrocarbon oil can be mixed with the transformation products to be sent to the separate catalysis zone, at any suitable point on the path followed by these transformation products between the catalytic cracking zone to high temperature and the separate low temperature catalysis zone.

   The product leaving the separated catalysis zone is fractionated into fractionated vapors with boiling points essentially in the range of gasoline and into hydrocarbon fractions with higher boiling points, which are condensed and made. leaving the fractionation zone and being brought, at least in part, into the high temperature oatalytic cracking treatment zone, while the gasoline product is condensed practically free from olefinic hydrocarbons and that it is collected in the fractionated vapors.



   According to a variant of the latter embodiment, the transformation products in the vapor state originating from the high-temperature catalytic cracking treatment are fractionated in a first fractionation zone, the products being taken out of this first fractionation zone. fractionated vapors with boiling points substantially in the range of gasoline and, with or without condensation and separation of intermediate gases, they are mixed with a relatively saturated hydrocarbon oil, preferably an oil having the character of a distillation product, and the mixture thus obtained is brought into hot contact with the cracking catalyst in the cracking or catalysis zone at low temperature,

   while the insufficiently transformed hydrocarbons at boiling points higher than the range of gasoline are condensed and taken out of each of the first.; and second fractionation zones as fractions of reflux of condensation and made to return, at least in part

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 in the. high temperature cracking zone to undergo further transformation. the examples given below relate to a certain number of operations carried out according to the invention and indicate the yields obtained as well as the nature of the saturated gasoline product.

   The numerical data of these examples are intended to demonstrate the value of the method according to the invention, but should not be construed as limiting the scope.



  Example I.



   The catalyst employed in this example was prepared in the general manner previously described and consisted of approximately 100 molar proportions of silica, 2 molar proportions of alumina and 4 molar proportions of zirconia. A commercial water glass of sodium silicate containing about 28.5% silicon dioxide and 9% by weight sodium oxide was diluted with about 10 volumes of water. Hydrochloric acid was added little by little and with constant stirring the mixture until it was barely alkaline to phenolph ... talein. After the silica gel had formed and stirred thoroughly, a small additional proportion of hydrochloric acid was added so as to obtain an almost complete precipitate.



  The silica gel suspension was then made nearly neutral to sunflower again and placed on a filter. The product was washed on the filter with dilute aluminum chloride solution until sodium had disappeared from the filtrate, by the uranyl magnesium acetate test. The cake was then removed from the solution. filter), it was ground and slurried in a solution of aluminum chloride and zirconyl chloride in sufficient quantities to obtain the proportions of precipitated alumina and precipitated zirconia indicated above. Ammonium hydroxide was added to the slurry until the mixture was barely acidic to sunflower. Then we deposited

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 again the product precipitated on a filter and washed again.

   The cake was removed from the filter and dried at a temperature of about 120 to 150 ° C, then crushed to particles passing through a sieve of about 12 mesh per cm. The product was formed into pills, which were calcined at 815 ° C for about an hour to stabilize them for subsequent exposure to temperatures of this order of magnitude during the intermittent reactivation operations. that they undergo in practice transformation operations.



   Mixtures of gasoline obtained by thermal cracking of East Texas gas oil and additional quantities of gas oil itself were prepared. These mixtures were passed through the silica-alumina-zirconia catalyst, prepared as described above, under the conditions shown in the table below, where A refers to gasoline. of cracking and B with diesel. The additions of tetraethyl lead given in cc refer to a liquid volume of one US gallon corresponding to 3.785 liters.

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  N <SEP> of <SEP> operation <SEP> 1 <SEP> 2
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<tb> Composition <SEP> of <SEP> the <SEP> load <SEP> 40% <SEP> A <SEP> 75% <SEP> A
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<tb> 60% <SEP> B <SEP> 25% <SEP> B
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<tb> Coefficient <SEP> of <SEP> flow rate <SEP> hourly, <SEP> liquid <SEP> 1.0 <SEP> 1.0
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<tb> Temperature <SEP> in <SEP> degrees <SEP> centigrade <SEP> 427 <SEP> 371
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<tb> Pressure <SEP> absolute <SEP> in <SEP> atmospheres <SEP> 1.0 <SEP> 7.8
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<tb> Yields <SEP>:

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<tb> Liquid <SEP> total <SEP>% <SEP> in <SEP> volume <SEP> 85 <SEP> 90
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<tb> Loss <SEP> by <SEP> the <SEP> gases <SEP> and <SEP> heavy <SEP> products <SEP> 15 <SEP> 10
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Final boiling <SEP> <SEP> of <SEP> 150 0.
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<tb> fraction <SEP> of <SEP> the first <SEP> <SEP> half hour <SEP> 23 <SEP> 0.5
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<tb> <SEP> fraction of <SEP> the second <SEP> <SEP> half hour <SEP> 56 <SEP> 4
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<tb> fraction <SEP> of <SEP> the <SEP> third <SEP> half hour <SEP> 64 <SEP> 12
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<tb> fraction <SEP> of <SEP> the <SEP> fourth <SEP> half hour <SEP> 71 <SEP> 26
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<tb> Percentage <SEP> distilling <SEP> up to <SEP> 150 C
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<tb> Load <SEP> 26.0 <SEP> 49.5
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<tb> <SEP> fraction of <SEP> the first <SEP> <SEP> half hour <SEP> 52.0 <SEP> 70.0
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<tb> <SEP> fraction of <SEP> the second <SEP> <SEP> half hour <SEP> 40.0 <SEP> 59.5
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<tb>
<tb> <SEP> fraction of

  <SEP> the <SEP> third <SEP> half hour <SEP> 37.0 <SEP> 58.0
<tb>
<tb>
<tb>
<tb> fraction <SEP> of <SEP> the fourth <SEP> <SEP> half hour <SEP> 38.0 <SEP> 55.0
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Percentage <SEP> distilling <SEP> up to <SEP> 205 C.
<tb>
<tb>
<tb>
<tb>



  Load <SEP> 37.5 <SEP> 72.0
<tb>
<tb>
<tb>
<tb> Product
<tb>
<tb>
<tb>
<tb> <SEP> fraction of <SEP> the first <SEP> <SEP> half hour <SEP> 70.0 <SEP> 90.0
<tb>
<tb>
<tb>
<tb> <SEP> fraction of <SEP> the second <SEP> <SEP> half hour <SEP> 55.0 <SEP> 81.5
<tb>
<tb>
<tb>
<tb> <SEP> fraction of <SEP> the third <SEP> <SEP> half hour <SEP> 52.0 <SEP> 78.0
<tb>
<tb>
<tb>
<tb> fraction <SEP> of <SEP> the fourth <SEP> <SEP> half hour <SEP> 52.0 <SEP> 76.0
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> <SEP> properties of <SEP> gasoline <SEP> to <SEP> boiling point <SEP>
<tb>
<tb>
<tb>
<tb> tion <SEP> final <SEP> of <SEP> 1500.

   <SEP> in <SEP> the <SEP> load
<tb>
<tb>
<tb>
<tb> Octane index <SEP>, engine <SEP> process <SEP> <SEP> 71.0 <SEP> 71.0
<tb>
<tb>
<tb>
<tb> Octane index <SEP> <SEP> after <SEP> addition <SEP> of <SEP> 6cm3
<tb>
<tb>
<tb>
<tb> of <SEP> lead <SEP> tetraethyl <SEP> 81.5 <SEP> 81.5
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> <SEP> properties <SEP> gasoline product <SEP> <SEP> compre-
<tb>
<tb>
<tb> nant <SEP> the <SEP> fractions <SEP> 1 <SEP> & <SEP> 2 <SEP> 1 <SEP> & <SEP> 2 <SEP>
<tb>
<tb>
<tb>
<tb> Final boiling point <SEP> <SEP> 205 <SEP> 150 <SEP>. <SEP>
<tb>
<tb>
<tb>
<tb>
<tb>



  Octane <SEP>, <SEP> process <SEP> of the <SEP> engine <SEP> 72 <SEP> 68
<tb>
<tb>
<tb>
<tb> <SEP> number of octane <SEP> with <SEP> 3cm3 <SEP> of <SEP> lead
<tb>
<tb>
<tb>
<tb> tetraethyl <SEP> 83.5
<tb>
<tb>
<tb>
<tb> <SEP> number of octane <SEP> with <SEP> 6cm3 <SEP> of <SEP> lead
<tb>
<tb>
<tb>
<tb> tetraethyl <SEP> 90.5
<tb>
 
We can see from the table above that after about the first hour of operation in operations at 427 G or 371 C,

   the bromine numbers are very low in the product boiling below 15OQ04 It is also seen that the yield of this product is very high during the first hour and that the yield during the second half hour is slightly

 <Desc / Clms Page number 24>

 lower than the first
It will also be noted that the fraction with a final boiling point of 205 C of the products of operation n 1 and more particularly the fraction with a final boiling point of 150 C of the products of operation n 2 at low temperature are notably more sensitive to the action of tetraethyl lead.

   In the case of the last fraction with a final boiling point of 150 c, the octane number is three units lower than that of the corresponding product of the charge, but nine units higher, when the same is added to it. proportion of tetraethyl lead. The low values of the bromine number indicate that saturation is almost complete and that there are no substantial proportions of olefins or diolefins, open chain or cyclic in nature.



   It is evident from the foregoing that the best results in operations of this type can be obtained with short running periods and a relatively fresh and active catalyst. These conditions are achieved by short running cycles or by employing the catalyst for short periods of time and then reactivating it to burn off traces of carbon deposits, and this characteristic is part of the process. invention.



  Example 2.



   In this example, a hydrocarbon oil fraction containing saturated hydrocarbons at boiling points in the range of gasoline and kerosene is mixed with the hydrocarbon oil at boiling point. boiling points within the corresponding range, obtained in a thermal cracking plant and the mixed oils are subjected to a catalytic treatment. The transport of hydrogen to thermal cracking hydrocarbons at boiling points in the range of those of gasoline takes place during this catalytic treatment by decomposition of the hydrocarbons.

 <Desc / Clms Page number 25>

 Saturated bures mixed with them.



   Mid-Continent crude oil, specific gravity 0.8448, was charged to the fractionation tower of a thermal cracking plant and the heavier hydrocarbons from the oil were passed through. crude with the reflux of condensation formed in the fractionation tower, in the heating element and in the reaction chamber of the thermal cracking plant. The oil was heated to a temperature of 499 ° C. passed through the reaction flesh at a pressure of about 17 atmospheres.



  The transformation products were removed from the reaction chamber and separated into a vapor fraction having a final boiling point of 205 C, a light fraction of oil having a boiling point within the interval of ordinary kerosene. a heavy recycling product which has been returned to the thermal cracking installation mixed with the untreated hydrocarbon oil admitted, and as a heavy residue, which has been discharged from the cracking installation king pyrolytic.

   The 205 C final boiling point fraction and the aforementioned light oil fraction contained both thermal cracking gasoline and saturated hydrogen transport oil. These oils were passed through a separate heating element, where. the mixture of oils was heated to about 399 ° C. under a pressure of about.



  4 atmospheres, then in a catalytic reaction chamber. containing the silica-alumina-zirconia catalyst, where the heated oil mixture was contacted with the catalyst with an hourly flow coefficient of about 1. The products were separated to form a gaseous fraction, a gasoline fraction with a final boiling point of 150 C and a fraction containing hydrocarbons with higher boiling points, which has been returned to the thermal cracking installation, to undergo a new cracking treatment.

   As a result of this operation, we obtained 58%

 <Desc / Clms Page number 26>

 gasoline with a final boiling point of 150 ° C., having a bromine number of 4 and an octane number of 71, which reached about 92 by the addition of 6 cm5 of tetraethyl lead per US gallon of 3,785 liters.



  Example 3.



   In this example, the gasoline and the reduced crude fractions fractionated from a crude oil were separately subjected to thermal cracking and the gasolines thus obtained were mixed with a gas oil fraction also fractionated from 1. crude oil, and the mixed oils were passed through the catalyst treatment zone. The transport of hydrogen was carried out by using virgin gas oil as hydrogen supplier and thermal cracking and reforming gasolines as hydrogen receptors.



   A crude oil from the "Mid-Continent" constituting the product of the feedstock with a specific gravity of 0.8448 was fractionated so as to separate a light fraction with a final boiling point of 246 C, an intermediate fraction called gasoil at. final boiling point of 400 Co and a reduced crude fraction containing crude oil boiling above 400 C. The light distillation fraction was reformed by heat treatment at a temperature of 549 0 and under a pressure greater than atmospheric pressure of 51 atmospheres and the reforming gasoline was separated from the gaseous by-products.

   The reduced crude fraction was passed mixed with the recycle product through the heating element and into the reaction chamber of a thermal cracking plant, where the oil was cracked at a temperature of 499 C and at a pressure greater than atmospheric pressure of about 17 atmospheres.

   The products of this transformation were separated into a gaseous product, a gasoline fraction with a final boiling point of 205 C, a fraction containing the hydrocarbons with intermediate boiling points,

 <Desc / Clms Page number 27>

 which was made to return to undergo a new thermal cracking, and a non-vaporized liquid residue. The product of the distillation of thermal cracking and reforming at a final boiling point of 205 C was mixed with the aforementioned gas oil and subjected to to the mixture a catalytic treatment. The mixture was heated to a temperature of 399 ° C. and brought into contact with a silica-alumina-zirconia catalyst, at an hourly flow rate coefficient of about 1, and under a pressure of about 1 hour. - less than atmospheric pressure of 7 atmospheres.

   The transformation products were fractionated to separate a gas fraction, a gasoline with a final boiling point of 15,000 and a fraction with higher boiling points, which were returned to undergo a further thermal cracking treatment. . As a result of this operation 55% gasoline with a final boiling point of 150 C was obtained, having a bromine number of 2 and an octane number of 68 which reached 90.5 by addition of 6 cm3 of lead. tetraethyl per US gallon of 5.785 liters of gasoline.



    Example 4.



   In this example, gasoline containing a relatively high proportion of olefins and obtained by sputtering in the presence of a catalyst at a relatively high temperature was mixed with a saturated hydrocarbon oil and the mixture was subjected to a new catalytic treatment for carrying out hydrogen transport reactions.



   We sprayed a specific gravity "East-Texas" diesel
0.8724 and was heated to a temperature of about 500 ° C., under a pressure above atmospheric pressure of about 4 atmospheres, without noticeable pyrolytic cracking, then
 EMI27.1
 it was passed over a silica-alumina-zirooIB catalyst with an hourly liquid flow rate coefficient of about 4 while maintaining approximately the same temperature and the same pressure on the vapors undergoing the oatalytic transformation. The transformation products are partially cooled and,

  we ..nI he

 <Desc / Clms Page number 28>

 splits, using as a portion of the refrigerant oil, a diesel fuel similar to that charged in the primary catalytic cracking zone. The following separations were carried out: a gas fraction, a mixed condensed fraction consisting of partially processed products and refrigerant oil in approximate proportions of 3 to 1, respectively, and an unvaporized liquid residue. The mixed condensed fraction was subjected to a catalytic treatment to effect the transport of hydrogen in the presence of a silica-alumina-zirconia catalyst, at a temperature of 399 C, with an hourly flow coefficient of the liquid. of 1, at a pressure greater than atmospheric pressure of about 4 atmospheres.

   The transformation products of this treatment were fractionated and separated into a gas fraction, a gasoline fraction with a final boiling point of 150 C and a fraction containing the transformation products with higher boiling points, which is returned to the catalytic installation described in the first place to undergo a further treatment. A running cycle of one hour before the regeneration was carried out in the first operation, a half-hour cycle in the second operation, and as a result of this treatment, about 55% by volume of gasoline was obtained. at a final boiling point of 150 ° C., having a bromine number of 10, and an octane number of 80, which reached 96 after the addition of 6 cm3 of tetraethyl lead per gallon of 3.785 liters of gasoline.



  Example 5.



   In this example, a gasoline containing a relatively high proportion of olefinic hydrocarbons, obtained in much / much the same manner as in Example 4, was mixed with a straight run naphtha gasoline, followed by undergo the mixture a catalytic treatment to carry out the hydrogen transport reactions.

 <Desc / Clms Page number 29>

 



   0.8724 specific weight "East-Texas" diesel was vaporized and heated to about 500 ° C, without noticeable pyrolytic cracking. The heated vapors were passed at a pressure above atmospheric pressure of about 4 atmospheres over a silica-alumina-zirconia catalyst, with an hourly liquid flow coefficient of 4, keeping the temperature of the vapors low. near to the same value as they left the heating element.

   The transformation products were fractionated so as to separate a gas fraction, a distillation fraction with boiling points approximately in the range of those of gasoline, an intermediate fraction which was obtained. returned for further catalytic treatment in combination with the untreated product of the feed and an unvaporized residue. The distillation mixture was mixed with a straight run naphtha gasoline having a specific weight of 0.7796 and boiling points between 150 and 260 ° C., in respective proportions of 55 and 45% by volume.

   Then the mixture was passed to the hydrogen transport zone, in which the mixed oil was heated to a temperature of 399 C and brought into contact with a silica-alumina-zirconia catalyst, with a coefficient of hourly flow rate of the liquid of about 1 and at a pressure above atmospheric pressure of about 4 atmospheres. The transformation products were separated into a gaseous fraction, a gasoline fraction with a final boiling point of 150 ° C. and the transformation products with higher boiling points which were returned to the first zone. of catalytic cracking to undergo a further transformation.

   A one hour cycle before regeneration was carried out in the first high temperature cracking zone and a half hour cycle in the hydrogen transport zone. As a result, we obtained an essence with

 <Desc / Clms Page number 30>

 final boiling point of 150 C. in a proportion of 42.5% by volume of the feed in the first cracking zone or high temperature zone and this gasoline had an octane number of 81.5 and an index of bromine of 114. The octane number of this product reached 87 after addition of 6 cc of tetraethyl lead per gallon of 3.785 liters of gasoline.

   The gasoline with a final boiling point of 150 ° C from the second operation or hydrogen transport operation was obtained in a proportion of 62% by volume of the mixture charged to this zone and had an octane number of 79. with a bromine number of about 7. The octane number of this product reached 98 after the addition of 6 cc of tetraethyl lead per gallon of 3.785 liters of gasoline.
 EMI30.1
 



  / P "; 1 CLAIMS.



  AJfJ 1,, a process for the production of gasoline with a high octane number and relatively low olefin content, which consists of adding a relatively saturated hydrocarbon oil to gasoline hydrocarbons containing olefins and soul. ner the mixed hydrocarbon oils in contact with a cracking catalyst at a temperature under a pressure and for a period of time such as to cause a decrease


    

Claims (1)

EMI30.2 olefin content of gasoline hydrocarbons' containing and processing, / / containing olefins, / undergoing treatment. 2. The process of claim 1, wherein the mixture of the relatively saturated hydrocarbon oil with the gasoline hydrocarbons containing olefins is contacted with a calcined mixture of the precipitated hydrated oxides selected from those. from the group comprising silica and alumina, silica and zirconia, silica, alumina and zirconia, this mixture being substantially free of alkali metal compounds, at an elevated temperature below 482 C, preferably included in the interval from 315 to 425 C, and under a pressure between a sensing pressure <Desc / Clms Page number 31> equal to atmospheric pressure and 14 atmospheres or more so as to cause a noticeable reduction in the EMI31.1 olefin content of gasoline hydrocarbons containing (YI?! J 1fiJ-- 'and. olefins /, undergoing treatment. 3o Process according to claims 1 and 2, in which the mixture of hydrocarbons is brought into contact with a catalyst consisting essentially of molded particles, calcined obtained with a mixture in high proportion by weight of hydrated silica precipitated in composition with a low proportion by weight of a precipitated hydrated compound chosen from those of the group consisting essentially of alumina, zirconia, lthalumina and zirconia, this catalyst being substantially free of alkali metal compounds. 4-. Process according to one of Claims 1 to 3, in which the mixture of hydrocarbons is brought into contact with a catalyst; the preparation of which comprises the operations which consist in preparing, starting with precipitated hydrated silica and a hydrated compound chosen from / those of the group comprising alumina, zirconia, alumina and zirconia, a complex product substantially free of alkali metal ions, drying the combined product and preparing with this product calcined particles at a temperature above about 480 ° C. 5. Process according to one of claims 1 to 4, in which the mixture of hydrocarbons is brought into contact with a catalyst, which has been prepared by precipitating a silica gel by acidification of an aqueous solution of a silicate. alkali metal, by purifying this gel to eliminate almost completely the compounds of alkali metals, and by intimately mixing with it a hydrated compound selected from those of the group comprising alumina, zirconia, alumina and zirconia these compounds being substantially free of alkali metal impurities, drying the mixture and transforming the dry mixture into calcined particles. <Desc / Clms Page number 32> 6. Process according to one of claims 1 to 4, in which the mixture of hydrocarbons is brought into contact with a catalyst, which has been prepared by precipitating together hydrated silica with a hydrated compound selected from those of the group comprising alumina. , zirconia, alumina and zirconia, purifying to almost completely remove alkali metal compounds, drying the purified mass and turning the dry mass into calcined particles. 7. Process according to one of Claims 1 to 6, in which a continuous catalytic transformation is carried out on a mixture of hydrocarbons, in which the relatively saturated hydrocarbon oil is a gasoline of direct distillation, a petroleum. lampant or diesel. 8, Process according to one of claims 1 to 7, in which the catalyst is regenerated intermittently, while the hydrocarbon mixture is continuously transformed and the transformed products are fractionated to obtain the strongly anti-knock gasoline. containing relatively small proportions of olefinic hydrocarbons, a hydrocarbon oil with boiling points above the range of gasoline, and a normally gaseous fraction 9. The method of claim 8, wherein the gasoline hydrocarbons containing olefins to be treated are obtained by a separate thermal cracking operation and are returned, at least in part, the hydrocarbon oil having boiling points above the range of gasoline and fractionated into the catalytic transformation products in the thermal cracking zone for further transformation. 10. The method of claim 8, wherein the hydrocarbons containing olefins to be treated are obtained by a separate catalytic cracking operation, and the oil is returned, at least in part, to the boiling point hydrocarbon oil. greater than the range of gasoline <Desc / Clms Page number 33> and fractionated into the catalytic transformation products for the production of low olefin gasoline in the catalytic cracking zone for further processing. 11. Process according to one of claims 1 to 7, in which a combined feed formed from a mixture of untreated hydrocarbon oils and partially transformed as indicated below, undergoes a thermal cracking treatment, the Vaporized transformation products from this thermal cracking treatment are fractionated in the state of admixture with added hydrocarbon oil forming the product of the feed and the boiling point hydrocarbons included in it. range from those of gasoline are separated by this fractionation from the higher boiling point elements of the feed product and vaporized transformation products, while those higher boiling point elements comprising partial hydrocarbons - directly processed and the product of the charge fresh, are condensed and collected as a portion of the combined feed to undergo the thermal cracking treatment, hydrocarbons with boiling points in the range of those of gasoline are brought to a catalytic processing zone - lytic in contact with a cracking catalyst under operating conditions such as to form gasoline with a low olefin content, the transformation products of this catalytic transformation operation are fractionated so as to separate the gasoline product from low olefin content of the partially processed heavier hydrocarbons, which are condensed and returned to the thermal cracking treatment zone as another portion of the combined feed, and the product d is collected. 'low olefin gasoline: 12. Process according to one of Claims 1 to 7, in which a light hydrocarbon oil is subjected to dis- <Desc / Clms Page number 34> direct tillation a thermal reforming or reforming and with a heavier hydrocarbon oil a thermal cracking in a combined plant for the treatment of thermal oracking and reforming, the gasoline of thermal cracking and reforming thus obtained is mixed with an oil of saturated hydrocarbon and the resulting mixture is brought into contact with a cracking catalyst under operating conditions such as to form products containing significant proportions of high octane gasoline and high octane gasoline. relatively low olefins, these transformation products are fractionated to separate this low olefin gasoline product from the heavier hydrocarbons contained in the transformation products, this gasoline product is collected and these heavier hydrocarbons are condensed and returned to the tank. thermal cracking treatment area. 13. Process according to one of claims 1 to 7, in which a hydrocarbon oil is converted to a large extent into gasoline by contact with a cracking catalyst at a relatively high temperature in a high temperature cracking zone, the products emerging from this high temperature cracking zone are mixed with a saturated hydrocarbon oil and the mixture of oils is brought, in a separate catalysis zone, into contact with a cracking catalyst under operating conditions such as to form a gasoline substantially free of olefinic hydrocarbons, which is collected, while at least in part, the higher boiling point hydrocarbons from the transformation in the zone are returned to of separate catalysis, in the high temperature cracking zone. 14. Process according to one of claims 1 to 7, in which a hydrocarbon oil is converted to a large extent into gasoline by contact with a cracking catalyst at a relatively high cracking temperature. <Desc / Clms Page number 35> this gasoline is mixed with a saturated hydrocarbon oil and the mixture is brought, in a separate catalysis zone, into contact with a cracking catalyst under working conditions such as to form transformation products containing high proportions of 'gasoline, substantially free of olefinic hydrocarbons, the transformation products leaving this separate catalysis zone are fractionated to separate the gasoline product substantially free of olefins from the heavier hydrocarbons, this gasoline product is collected and these heavier hydrocarbons are returned to the catalytic oracking treatment zone at a relatively high temperature.