BE470846A - - Google Patents

Description

       

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  Hydrocarbon conversion process
The present invention relates to the catalytic transformation of hydrocarbons such as the fractions obtained from or originating from petroleum or other carbonaceous or hydrocarbonaceous substances, and relates in particular to the conversion processes in which a catalyst of cracking, as for example to cause the breaking of carbon-to-carbon bonds, or in typical reactions which occur during the reforming of liquid products in the boiling range of engine fuels.



   For this purpose, it has been proposed to use as contact masses in the catalytic transformation of hydrocarbons certain natural earths and clays. Many of those materials which have been tried in cracking, reformation or related reactions have been found to be adequate for the purpose

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 intended, since in many of these the catalysts which were formed have been found to be essentially inert, or have a tendency to promote excessive deposition of carbonaceous substances which is not only undesirable in itself, but gel deposition causes a rapid decrease in catalytic activity, necessitating frequent regeneration after comparatively little continuous running time.



   The value of a contact material as a catalyst in the process in question depends on its ability to form selectively from the quantity charged, optimum quantities of the desired liquid hydrocarbons, such as products suitable as motor fuels, with an optimum quantity. minimum production of gas and coke. For example, a contact material which is relatively catalytically inert, such as diatomaceous earth or kieselguhr, when intended for use in a cracking operation results in products which vary little. in quality and quantity of those obtained by thermal cracking in the absence of such a contact material.



  On the other hand, there are contact materials of natural or synthetic origin which have the property of forming, from petroleum hydrocarbon fractions, large quantities of carbon and low molecular weight gases comprising hydrocarbon gases, to the limit of the desired liquid fractions. Such contact materials, too, are not ordinarily suitable, and are not desirable, as decracking or reforming catalysts.



   Among the natural adsorbent materials which are rather essentially inert or otherwise impractical as catalysts for the conversion of hydrocarbons, because they produce large amounts of coke and / or gas compared to the gasoline yield, there are certain clays which can be activated using known methods, such as acid treatment, to produce

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 catalysts. of acceptable quality. Many of the available clays, however, do not react to the usual methods of activation to produce catalysts having an acceptacle activity level, and are therefore considered unacceptable for commercial use as cracking catalysts. or reformation.



   The clays which occur in nature usually contain, besides the main compounds and complexes of silica and alumina, lesser amounts of compounds of iron, calcium, magnesium, etc. Others too, may contain among their lesser components, zirconium or titanium compounds. When selecting natural adsorbent materials as catalysts, it was previously observed in United States Patent No. 2,078,945 to Eugene J. Houdry that the content of iron compounds is critically related to the capacity of the iron. mass in contact to be regenerated without appreciable loss of catalytic activity. The patent indicates that contact masses suitable for use as catalysts should not contain more than 3% iron oxide.



   Although a large part of the iron compounds which appear in, or constitute components of many clays are found present in such a form that they can be largely removed from them, as for example in With the aid of a conventional acid treatment, such processes result, as in the bentonite-type clays which can be activated in the first way and used as catalysts, in products always containing about 1.5% iron, or more. , calculated as ferric oxide. The acid treatment also removes portions of the aluminum content from the clay so that if the remaining clay is to be used where the aluminum content is an important consideration, such as in catalyst preparation, the extent of treatment should be limited by
 EMI3.1
 corresponding way.

   Therefore, during reduced treatments z

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 or more violent, additional amounts of iron compounds can be removed, but the products thus obtained become increasingly weak in physical properties and as they accompany the extraction of relatively large amounts of aluminum compounds. , the treatment causes a marked decline in catalytic activity, eventually resulting in products having such reduced catalytic activity that they cannot be used for this purpose.

   Although we do not wish to be bound by any scientific explanation, there is reason to believe that the iron compounds which are less easily eliminated from argilloferruginous clays are in a different form than the iron compounds. easier to extract, being intimately associated in a complex with silicon or perhaps forming part of the structure of the network by addition to, or as a replacement for, other main cations of the pattern.

   This form of iron compound can be broadly considered to be "isomorphic", although it is recognized that the structure of the clay does not necessarily have to be crystalline and that fractions of the whole as of. More vigorously attached iron compounds may differ in shape from that of the major structural components of clay.



   In our adjacent application attached to the same date, special processing methods are shown in which the iron content of argilloferruginous materials can be materially reduced below. of the point obtained during the conventional activation of clay, and other properties of the substance are changed.



  By the methods which are described here, active cracking catalysts with unique properties are obtained by removing most of the iron fraction which cannot be selectively extracted by acid treatment without being accompanied by an removal of alumina and without otherwise lowering the catalytic activity.

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   The new catalysts, obtained by the method described are charac- terized by important differences in physical properties which cannot be attributed entirely to their reduced iron content and therefore it is assumed that some structural changes must have occurred. - reduce as a result of the new treatment described for clay. For example, the new products no longer shrink materially at high temperatures (16003 F), withstand very high temperatures without noticeable decrease in catalytic activity, and exhibit a distinct pattern on X-rays.

   Incidentally, the new catalysts generally have a characteristic color difference, being whiter or lighter than the natural clays from which they are prepared, and notable differences in spectrograms are also observed.



   In accordance with the present invention, processes for the conversion of hydrocarbons of the type employing clays or other cracking catalysts are advantageously improved by the use of clay catalysts as described below having a content of. iron materially lower than that of active clay catalysts which can be obtained by conventional acid activation carried out on the same raw clay materials.



   The catalysts having the low iron content are such that a fraction of the iron from the clay which is found to be bound more vigorously has been removed in addition to the iron which can normally be removed by the usual acid activation. Suitable clay catalysts in accordance with the present invention can be prepared by the methods described in the applications identified below or by methods described below.



   Among the advantages offered by the catalysts employed in accordance with the present invention, there is an unexpectedly low initial production of heavy and sulphide deposits and

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 surprising resistance to "abnormal aging" and deterioration by strongly corrosive charges, in continuous operation. The gasoline / coke and gasoline / gas weight ratios with lighter feeds can be significantly improved, and indeed our catalysts have in many cases exhibited surprisingly better gasoline / gas ratios than commercial synthetic catalysts.

   Our catalysts are able to withstand more severe conditions and higher regeneration temperatures in current use, which together with longer catalyst life and significantly improved yields. The desired cracking products constitute significant economic advantages in addition to those which result from the use of easy-to-use raw materials. obtainable and inexpensive. In addition, it is now possible to operate more efficiently and economically with sulphide products and other corrosives which rapidly deteriorate other catalysts based on ordinary clay.



   When the iron content of the clay is found to be reduced as described here, the catalyst prepared from it sees its properties progressively improved and the important advantages stated above become more accentuated thanks to the structural changes which are assumed. occur simultaneously with or as a consequence of the release of isomorphic iron.

   The various steps of the process should, however, be controlled in order to minimize the correlative removal of alumina, particularly in clays with a comparatively low initial alumina content. A marked improvement in the catalytic properties of the based catalyst. of clay with gradual removal of iron usually appears when the content of iron compounds is reduced to about that corresponding to 0.4% Fe203 (by weight), although catalysts with an iron content of zero:

  lower rate such as for example those having less than 0.3% Fe203 are preferable and in particular for loads

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 corrosive, the best results are obtained with catalysts having an iron compound content of less than 0.2% Fe203 (percentages being understood dry).



   The improved catalysts, having an exceptionally low iron content and having the advantageous properties and characteristics mentioned above can be obtained by treating the clays so as to transform the iron compounds into a form soluble in an acid medium, for example soluble salts, comprising that fraction of the iron which is present in a form which is not effectively and selectively removable by acid washing, the iron being made capable of subsequent extraction by treatment with iron. using a weak acid, for example and / or by washing or in certain cases by volatilization. According to one of the preferred clauses, the clay or earth is subjected essentially in dry form to a treatment with a gas or a chemically reactive vapor at elevated temperature.



  The reagent chosen is that which gives a salt forming reagent capable of producing a salt with the iron released at that time.



  According to the theory stated above, although it is not desirable to be bound by it, there is reason to believe that the iron present constituting as a complex with silicon or otherwise a part. of the reticular structure either as an addition or replacement of other: principal cations of the unit, is transformed by the treatment with gas or steam at high temperature into simpler or more reactive compounds such as salts which are soluble in / or which react with the acid which can be used during the subsequent washing.

   For example, it has been observed that by treating "Filtrol" clay (an acid-active commercial montmori rillonite) at high temperature with a gas or vapor of the type described, the product clay obtained by subsequent exposure to oxidizing conditions, exhibits the characteristic red color of

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 ferric oxide, which is not formed by oxidation of untreated "Filtrol" clay. Observation of the properties and characteristics of the new catalyst leads above all to admit that, by selective elimination of the iron compounds, as described , it is possible to force a new duct in the clay, distributed evenly in the hold:

  traps and consequently causing an increased and uniform adsorption capacity.



    Dry treatment with;:. Az or 1; ... high temperature steam can be preceded and / or followed by wet treatment with mineral acid or an organic acid which forms soluble iron salts or complexes, including lower aliphatic carboxylic acids such as oxalic and acetic acids as well as hydroxy acids including lactic acid and said sweet acids.

   There where. the acid treatment precedes, the most available iron compounds (e.g. outside the crystal lattice) are converted into soluble iron salts which are removed as in the known acid activation of benzonites, and the residual iron compound (e.g. example chemically combined in the network) can then be treated more radically by the gaseous treatment agents. Acid treatment following dry gas treatment is effective in helping to remove products formed by the reaction of gaseous agents with the complex or less accessible iron compound. It will immediately be understood, therefore, that it may be desirable to employ an acid treatment both before and after the high temperature gas or steam treatment.



   During the preparation of the catalyst, according to a preferred clause, treatment with a weak acid is desirable to remove surface impurities and with a clay of the montmorillonite group, such as

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 Acid-activatable bentonite, the initial acid pretreatment is particularly advantageous since the otherwise low porosity of the clay prevents penetration by the gaseous or vapor-state treating agent. In general, with kaolin type clays the acid pretreatment is less significant, although with some kaolin type clays an advantage will also be found in the acid pretreatment.



  The acid pretreatment can be carried out in a manner known in the art for "acid activation" in the manufacture of bleaching clays. For example, the acid treatment can be carried out on finely divided clay while the clay is in suspension in water as in the nature of a mud, to which is added a concentrated acid such as for example l hydrochloric acid or sulfuric acid, or a weak acid can be added directly to the finely divided clay. In each case, the ratio of acid to clay is preferably in the range of 30 to 40%. The mixture of clay and acid is preferably heated to about 160 to 2109 F over a period of 2 to 12 hours, then washed with water and filtered.

   If desired, the clay can at this time be washed until the acid ions disappear with corresponding extraction of the soluble metal salt. The acid treated clay with or without washing purification can then be dried in any known or desirable manner. More concentrated or larger amounts of acid may be employed and / or higher temperatures involving higher pressures, and also longer treatment times up to the approximate limit at which the combined effects. tend not to selectively remove iron compounds without undesirable disappearance of the aluminum compounds.

   This point cannot always be

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 precisely defined as to the chemical composition of the acid treated clay, because the optimum point varies with the origin of the raw bentonites. For many, if not for most crude bentonites, however, this point is reached when the weight percentage of A1203 in the treated clay drops so much in the range of 25 to 5%. Yet it is preferable. to use less vigorous acid treatments close to the designated limits. Acidic clay treatments such as, for example, those described in US Patents 1,397,113, 1,579,326, 1,642,871 are desirable.

   The acid pretreatment, therefore, may be less stringent than required for activation and may be sufficient as soon as it opens pores in the clay, thus allowing easy access to the gas or vapor employed. during the process.



   The untreated clay or the acid-treated clay described above, or an acid-treated clay obtainable commercially such as "Filtrol" or "Super-Filtrol" in finely divided dry form , or which, after having been formed into an agglomerated mass, for example by granulation, molding, extrusion, etc. (as is practiced for making clay catalysts) is subjected to the gas or steam treatment at a temperature preferably in the range of about 1200 F at the temperature which would cause rapid shrinking or even shrinking. beginning of appreciable melting of the clay.

   Since clays vary in composition and properties including melting temperature, even when they come from the same source, one cannot define an exact temperature range. It has been observed that with clays of the montmorillonite type, the maximum temperature can go up to 1500 and sometimes up to 1550 F, while in the case of clays of the kaolin type one can even use higher temperatures exceeding 1600 and 1650 F. Elimination

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 Substantial iron can be obtained at lower temperatures, such as 1000 F, but require repeated or prolonged processing in order to lower the iron content to the desired level.

   The quantity of gas or vapor employed should be at least sufficient to combine chemically with the quantity of iron present in the clay, but it is advantageously used in excess.



   As indicated above, the vapor or gas employed is such that it reacts chemically with the iron compounds initially present in the clay or which remain there after the preliminary acid treatment if it is practiced, including this fraction of the iron. intimately linked in the crystalline network or linked in some other way in a so-called "isomorphic" form. The reagents employed further act selectively on the iron content without affecting significant amounts of the aluminum or silicon compounds of the product to a degree which would lower the activity of the clay product as a catalyst.

   Where the gaseous treatment agent converts the iron compounds in the clay to vaporizable compounds at the treatment temperature, there is no need for further treatment to remove the iron. This will be the case, for example, in a treatment with gaseous chloride at 1200 to 14009-F during which the iron will be vaporized in the form of ferric chloride.

   In other cases, however, such as where the chlorine treatment is carried out at lower temperatures or where the reactive gas or vapor does not form volatile compounds, the iron compounds are nevertheless transformed by the treatment into a more accessible and easily removable form, such as iron salts which can be removed from the treated clay by washing with water or with a solvent for the iron salts, or by treatment with a dilute acid, with or without alternating washing with water. For example, clay can be treated with H2S at 1400 F and then washed with dilute hydrochloric acid.

   Instead of-

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 to wash out the processed iron compounds produced by the gas or steam treatment, they can be alternatively removed by further treatment with another gas or steam such as chlorine in order to be volatilized. tern In cases where a subsequent acid washing is not required to remove the iron, it has nevertheless been found advantageous to treat the clay with an acid after the gas or steam treatment, since in this way it is obtained. usually held more active catalysts.



   The invention includes, in addition to the preferred types of gaseous reagents already named, other gases or vapors capable of transforming the iron compounds of the clay into a simpler or more accessible form, such as phosgene, sulphide. of carbon, sulfur monochloride, sulfonyl chloride and sulfur vapors. As will immediately be understood, the more active gases or vapors will require lower temperatures than less reactive reactants for the same treatment vigor. For example, treatment with CS2 may require range of 1300 to 1400 F to obtain effects comparable to those of H2S at 1200 F.



   When the clay to be treated contains constituents or impurities which can react to give gases or vapors of the type described, the treatment agent can be chosen so as to react with the component or impurities in question as soon as possible. the start to form such gases or vapors in situ.



  For example, if argiele contains sulphate ions or sulphate compounds, which would be the case if it were left unwashed after treatment with sulfuric acid, the product can then be treated with hydrogen gas at determined temperatures forming hydrogen sulfide on reaction with sulfate, thereby achieving the effect of treatment with H2S. With acid activated clays such as bentonites containing residual sulfate, the

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 H2 gas treatment will be appropriate. Of course, if the
Waste SO4 is insufficient to provide the required amount of H2S, additional sulfate can be added to the clay as well as prolonged treatment with sulfuric acid or with a suitable sulfate.



   As indicated above, the improved catalysts of the present invention cannot be obtained by continuous or prolonged treatment of the clay with acid in order to reduce the iron content since attempts to extract iron from the clay by below a maximum elimination limit (obviously, at least in some cases, the point at which the immediately available iron is removed and only the "isomorphic" iron remains) results in a correlative elimination of excessive amounts of aluminum compounds with decreased catalytic activity.

   For example, a crude kaolin clay having an Al203 / Fe203 weight ratio of about 44 was vigorously treated with acid until the iron content was reduced to 0.27% Fe203, the iron content being reduced to 0.27% Fe203. product then contained only
2.3% A1203 and was practically inert as a catalyst.



   On the other hand, the present process ensures the selective removal of iron compounds without corresponding excessive removal of active components such as alumina as shown by the following tests: a) A kaolin clay having an initial content in
A1203 of 33% and an iron content corresponding to 1.4-% of
Fe203 was treated at 1400 F with H2S gas for 2 hours, followed by additional treatment with C12 gas at 1400 F for 2 hours, and washing at ordinary temperature by 15%
HCl.

   The treated product showed on analysis that the Fe203 content was only 1/4 of that of the initial product (0.35% Fe203) while the alumina content was only slightly reduced (30, 22 % A1203).

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 b) Another sample of crude kaolin with an initial content of 45.5% A1203 and 1.15% Fe203 after treatment with C12 gas @ 1400 F for 2 hours showed on analysis 0.44% Fe203 and 45 , 8% A1203.



   Although in some known processes of hydrocarbon conversion the catalyst may be employed in the form of finely divided particles or powders suspended in the feed, in other processes such as in static operations with a fixed or mobile catalyst. The catalyst is preferably used in the form of large aggregates or agglomerated masses such as pellets, tablets, coarse granules, etc. In the latter case, large aggregates can be formed at any stage in the production of the final catalyst, but preferably immediately after the preliminary acid treatment if carried out.

   These large masses can be formed by compressing the finely divided dry particles or powders in a pill-making machine or by pre-moistening the treated or untreated dry clay with water or other inert liquid which may be used. to bind the fine particles or powder into a cake which after drying can be broken up into granules or fragments of desired size, or the wet mixture can be converted into more regular shapes by molding, incorporation, fusion, extrusion, etc.

   There where. the high temperature gas or steam treatment described is carried out on a powder or on fine particles, the cohesive properties of the clay may be affected in which case it may be necessary to add a suitable binder or a lubricant to aid in the molding operation, ensuring the choice of such ingredients and keeping the addition to a minimum so as not to counteract the catalytic activity of the mass formed, so one can for example use a raw clay or acid activated having good cohesive properties as a binder for the treated clay.

   It is preferable, however, to carry out the treatment with gas or steam.

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 Written on clay in the form of granules, tablets, pellets or other agglomerated masses particularly where the final catalyst is to take the form of such large aggregates. If the catalyst is to be employed in a process for treating hydrocarbons in the form of fine particles or powders, the formation of larger aggregates for the iron removal treatment is not necessary, but, if one wants, large masses can be formed and processed according to the method described above and then crushed and pulverized to the desired degree of fineness.



   Although the catalyst prepared in accordance with the preferred process has already been subjected to high temperature treatment, it is still preferred, as a final step in the preparation of the catalyst for the hydrocarbon conversion process, to subject it. on calcination at a temperature above 800 F in air, with or without the addition of steam or in steam alone.



   In accordance with the present invention it is made possible not only to obtain improved catalysts from the activated clays employed heretofore, such as montmorillonites containing catalytically activated bentonites, etc., but by the new process. here exposed clays of uncommon low activity or belonging to the type which cannot be brought to practical high levels of activity by acid activation, and which could not heretofore have been successfully employed as a catalyst in In the course of cracking or reformation of hydrocarbons, there is now effective use in such processes.

   For example, a kaolin clay obtained from a deposit located on the neighboring Eccles property, Putnam County, Florida has been found to possess valuable catalytic activity without acid treatment or other preparation. Clays of this type can be brought to

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 Significantly higher activity levels with desired selective properties, thanks to the method described.



  Although it has been suggested in the literature that the adsorption capacity and activity of clay depend on the crystal structure, this claim is not confirmed by our experiments, since we have found among calcined kaolin clays also although among other clays products exhibiting an amorphous lattice by X-ray diffraction, Lais having an acceptable level of catalytic activity.



   By employing the catalysts in accordance with the present invention, no change in the conditions of the treatment of the hydrocarbon to be treated is made necessary. The usual conditions of weather, temperature, etc. can be followed if desired. As an example of a static operation, the cracking can be carried out at a temperature of 800 F to 900 F using a flow rate (feed volume, liquid basis per volume of catalyst per hour) of about 1.5 and a gauge pressure of about 15 pounds per square inch.

   The temperature can, of course, vary within a range of about 700 to 1000 F, the flow rate from 0.5 to d, and pressures can be used from atmospheric pressure or slightly lower down to about 100 pounds / square inch or even more. Under these conditions, the "continuous" operating time ranges from 50 to 60 minutes, for example 10 to 30 minutes alternating with periods of regeneration.



   In processes other than static, such as in those where the catalyst moves through the reaction zone, the conditions employed may be such that the oil is subjected to substantially equivalent conditions comprising a contact time and ratio. catalyst / oil identical to those indicated above for the static process. The catalyst passes, during its cycle, through a separate regeneration zone.

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   Reforming can be carried out in accordance with the invention by charging a fraction of fresh or cracked gasoline, or naphtha, under conditions similar to those employed in cracking. In all these processes, the catalyst is regenerated after use by bringing it into contact with air or other gases containing oxygen in order to remove carbonaceous deposits by combustion.



   The catalysts to which the invention relates also find their use in synthesis reactions, for example the polymerization of gaseous hydrocarbons into liquid products.



   In general, active catalysts prepared from kaolin clays provide a desirable distribution of the product from the viewpoint of the low molecular weight hydrocarbons (C5 and less) found in the fraction of. gasoline with substantial removal of low gas density compounds and, while the octane number of the obtained gasoline is generally equivalent to that obtained using the usual synthetic silica-alumina catalyst, the olefin content gasoline is usually a little higher in the case of the kaolin product.

   Due to the high density and the correlative high heat capacity of the catalysts prepared from kaolin clay, and also due to their greater heat stability, the entire charge can be introduced without having to resort to damaging regeneration temperatures to achieve the desired combustion of the coke in the cycle, since the physical properties of the kaolin catalyst, which have just been recalled, also lead to regeneration temperatures. approximately equal throughout the mass without accentuated looal charcoal.



   The term "kaolin" as used herein refers to raw clays or to modified clays derived therefrom.

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 green, clays in the raw state containing kaolinite,
 EMI18.1
 dickite, nacrite, halloysite or anauxite as the main mineral constituent present in clay.



   In the following examples the costing of the catalytic activity is expressed in terms of the Standard test.
 EMI18.2
 (CAT-A method) described in "Laboratory 1ilethod for) o-Ler ,, j2j-ning the Aotivity of Cracking Catalysts" by J. Alexander et} l. G.



  Shimp, page R 53 j, National Petroleum ews, Technical Bec- tion, August 2, 1944. According to the method, a light oil is contacted with the catalyst under determined cracking conditions and the activity of the catalyst is denoted by volume percent of gasoline obtained; the percent weight of wet gas, the density of the gas and the percent weight of carbonaceous deposit are also determined.
 EMI18.3
 



  Example 1.- Filrol clay pills (a commercial acid activated montmorillonite) are treated with an excess of H2S III-; JO. 13 'for 2 hours under conditions protected from air. , the appliance and its contents having been previously rinsed with asote. As a result of the treatment, the ulcers turn black. An equal volume of HCl at 15 days later was added to the pills afterwards and left standing at room temperature for 2 hours in
 EMI18.4
 shaking irregularly, the temperature initially rises with rapid passage of H2S and the color of the pills weakens noticeably. The acid mixture is then heated for 30 minutes in a steam bath, the temperature rising.
 EMI18.5
 at 14Q #: 5 '.

   After decantation, é is added. the, load of fresh 15% HCl in equal volume and left to stand for 22.5 hours, then exhausted and washed several times with distilled water on a filter, until the chlorides disappear.



  The total acid employed was about 35% on the weight of
 EMI18.6
 clay. After drying in an oven at 200 °, the pills were calcined in air at 1050 ° F for 2 hours. The
 EMI18.7
 pills then take on a whiter color than the Vi

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 early pills. When tested for their cracking activity on light oil, 37.3% gasoline by volume was produced with 2.6% by weight of coke and 4.9% by weight of gas.
 EMI19.1
 Since argillium Filtrol is a remarkable catalyst in the important commercial use of petroleum cracking, it was chosen for comparison at various activity levels with the iron-free catalyst of Example I.

   The tests were carried out under standard conditions of the GAT-A method on an East Texas light diesel fuel, and gave the following results:
 EMI19.2
 
<tb> ----------------------------------------------- --------------------
<tb>
<tb> Catalyst <SEP>: <SEP> Calcination <SEP> Gasoline <SEP> Coke: <SEP> Gas: <SEP> Density
<tb>
<tb>
 
 EMI19.3
 Fi1trQL catalyst: 14009 F-10 h. 34; 8 2.5 4.3 1.33 (Fe 0 == 2 0%) 5 vapor? 2 5 = --------- ¯¯¯¯¯¯l¯¯¯¯¯¯¯¯ ¯¯l¯¯¯¯¯l¯¯¯¯l¯¯¯¯¯¯ ----- 13509 F- 4 h. 29.4 2.0: 3.1 1.26 '100% vapor.

   J] .----------------------------------------------- --------------------: Exe.mp1e I: CFe203 ¯Ol% 1400S F-10 h. 33.0; 1.5, 3.0; 1.41. 5 '% steam: -------------- + --------- + ----- + ---- i --------- - 1350S F- 4 h. 27.2 1.0: 2.3: 1.37
 EMI19.4
 
<tb>: <SEP> 100 <SEP>% <SEP> steam
<tb>
 
The remarkable decrease in coke (40-50%) and gas produced by the new catalyst for about the same gasoline yield has even greater significance as an indication of the behavior of the catalyst in relation to feeds which produce a lot of coke, such as heavy petroleum oils. This emerges from the present cracking operation of a fraction of crude heavy oil from East Texas (27.6g API) in which it was compared with a typical commercial clay catalyst,

   the iron-free catalyst giving a 10% increase in gasoline greater than the recovered gasoline, with an offset; by 10% less in coke, and with approximately the same liquid recovery.



   Chemical analyzes of the Filtrol clay and the modified low iron catalyst derived from it are required.

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 fords below (calculated for a calcined product)
 EMI20.1
 : Filtrol ': Example I Filtrol; ¯¯¯¯¯¯¯¯¯-¯¯¯¯¯¯¯¯-¯¯¯¯¯¯¯-¯¯¯¯¯ Parts by weight: Sip2 constant real base j Si02 constant real box Si02 73, 9 73.9; 76.7 Al; :: 3 18.0 17.5 18, Fe 2.1, 09 0, l CaO 3.1, 96 1.0
 EMI20.2
 
<tb> MgO <SEP> 4, <SEP> 9 <SEP> 4, <SEP> 24 <SEP> 4 <SEP>, <SEP> 4 <SEP>
<tb>
 
It should be noted that although the iron and calcium compounds have been substantially reduced, the content of aluminum and magnesium compounds remains comparatively
 EMI20.3
 unchanged.

   The above analysis serves c.:. ' e: c3 ... 1: ple for the preferred types of acid activated montmorillonite clays according to the present invention comprising in the preferred range about. 93-97 ;; of silica and alumina (in weight ratio ranging from) 1/2: 1 µl. 5:

    1), the remaining 7-3% of the modified clay containing magnesium compounds as the main constituent, the magnesium preferably being in excess over the calcium to the extent of about three to four times or more that of the calcium compounds and other components of less importance, or it can comprise at least 75% of the ingredients other than silica and alumina, with the iron situated below 0.2%.



   The temperature stability characteristic of the catalysts of the present invention is shown significantly by the comparatively small change in pill density and porosity after heat treatment at 1600. F. While a typical commercial clay catalyst (placed) in the temperature range
 EMI20.4
 1500-l600é loses 50 7; of its porosity (measured by volume per cent), the catalyst of Example 1 did not exhibit appreciable ratination and a loss of porosity of less than

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 15%.

   Although with other active clays of the type
 EMI21.1
 bentonite porosity losses of 50% or more can be encountered under these conditions, the modified clays of the invention exhibited a relatively low loss of porosity. The preferred modified clays of the montmorillonite class according to the invention are those which lose less than 20% difference in porosity between the clay heated for 2 hours at 1500g F and heated for the same period at 1600g. F. The porosity by volume percent in the following table was obtained by measuring the volume of water absorbed by a pill of known volume, essentially
 EMI21.2
 in accordance with the ASTM method (D46g-42; Method A -. water abuo).

   The catalytic activity was well retained even after being subjected to the highest temperature noted, which temperature causes a rapid decrease in the activity of a commercial catalyst from the same source of clay. The results are shown in the following table:
 EMI21.3
 -------------------------------------------------- -----------------
 EMI21.4
 
<tb> Activity <SEP> after
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> 1600 <SEP> F.
<tb>
 
 EMI21.5
 1 ----------------------------------: -------------- --- ----------
 EMI21.6
 
<tb> Hot <SEP> treatment <SEP> <SEP> Gasoline <SEP> Coke <SEP>: Gas
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Catalyst <SEP> temperature <SEP> F <SEP> Vol.% <SEP>: weight: weight
<tb>
 
 EMI21.7
 : 1400: 156D: 155G:

   1600 [fµP. [P.V. [to.P * [B.V. [dlli19.V. [D.P. [P. '. I j Filtrol 1.08 - 1.12 53.6 1.4 v35.sv1.59'6.8; 1.2. 0.4 1.2 ------------------------------------------ "----- --------'------ '! ------- Ex :.] 1.01] -] 1.02] 58 1.05 55.0 1..14: 50.0 35.3 1.4: 4-.l 5 to ,, p.density of the pill pv = porosit6 in volume percent.



   The characteristic resistance of the new catalysts to sulfur and sulphides at high temperature is demonstrated by a comparison of these with typical clay catalysts having about the same initial level of activity ( 39).

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  -------------------------------------------------- ------------
<tb>
<tb> Activity <SEP> after <SEP> sulphurization
<tb> ----------------------------------------------- ---------------
<tb>
<tb> Gasoline <SEP> Coke: <SEP> gas <SEP> gas
<tb> Volume <SEP>% <SEP> weight <SEP> weight <SEP>% <SEP> dens.
<tb>
 
 EMI22.2
 -------- t ----------------------------------------- ------------:

   (a) Ji 'il trol: :::, (.oj reo) v. 2. n / a s.9. 0.5
 EMI22.3
 
<tb> (b) <SEP> Filtrol <SEP> ....
<tb>
<tb> processed <SEP> 38.7 <SEP> 2.5 <SEP> 7.9 <SEP> 1.55
<tb>
<tb>
<tb> (0.12% <SEP> Fe2O3)
<tb>
 
 EMI22.4
 1 ---------------- L ---------------- 1 ---------- L ---- ---- L --------
The catalyst in (a) above was a typical commercial acid activated clay while (b) was obtained by treating the same clay according to Example 1. The above sulfurization tests were obtained. were made with H2S at 1000 F for 2 hours. The results indicate the relative stability of the two catalysts and their behavior when used in the cracking or reforming of sulfur-containing products (compare Example V)

   Example II The tendency towards gasoline / gas and gasoline / coke ratios is evident in many examples when the iron content of the clay has been lowered to about 0.3% Fe2O3. For example, commercial acid activated montmorillonite, treated as in Example 1, except that
 EMI22.5
 the treatment with H2S is e8'iectaaii = µ, 11û0 -¯ F, providing a catalyst which compared favorably to the initial clay catalyst, as can be seen from the following table:
 EMI22.6
 
<tb>% <SEP>: Gasoline: <SEP> Coke <SEP> Gas <SEP> Gas
<tb>
 
 EMI22.7
 : i'e20j: Volume%: weight1o: weight densiz6 -------------------------------------- -------------------------:

   Catalyst to:: clay ini- 2 0: 9 9: - 4: a: tial actië, 0,. :) ": / '7:.
 EMI22.8
 
<tb> to <SEP> acid
<tb>
<tb>
 
 EMI22.9
 ", XemPle il-; -77: 301-9 2.7: 5.2: 1.49
 EMI22.10
 
<tb> ----------------------------------------------- ----------------
<tb>
 
 EMI22.11
 Example III A commercial acid-activated sub-bentonite clay R in pill form (-'04 ZF 4.3) was treated with. hydrogen gas for 2 hours at 1400 F in an air-free device. The product, which became gray-black, was then washed with hydrochloric acid at 5% concentration.

 <Desc / Clms Page number 23>

 tration until the dark color was completely gone,

   and then washed and dried. On analysis it was found that the initial iron content above 2% Fe203 had been reduced to 0.34% Fe203. The dried clay was then calcined in air at 1050 F for 2 hours and used in cracking a light gas oil under the standard test conditions designated above.

   A yield of 32.9% by volume of gasoline was obtained with the production of 1.9% by weight of coke and 5.6 by weight of gas having a density of 1.34 Example IV. - A montmorillonite clay from Pontotoc Mississippi (Fe203 = 5.38%) was treated with sulfuric acid at 15% concentration at room temperature for a period of 8 hours using: a quantity of acid (on the 100% basis) equal to 60% of the dried agile. After washing and drying the product was shaped into pills of about 4 mm. of diameter.



   (a) Part of the pills were heated for 2 hours in air at 1050 F. Analysis of the product gave 2.88% Fe2O3.



   (b) Another portion of the pills were treated with H2S at 1400 F for 2 hours. After cooling, the pills were washed with hydrochloric acid at 15% concentration at room temperature for 24 hours, washed with water, dried and calcined in air at 1050 F.



  Analysis of the product gave 0.11% Fe2O3.



   The activity of the catalysts produced according to (a) and (b) above is compared in Example X.



  Example V. - The following example shows the remarkable degree of stability of iron-free clay catalysts against highly sulfur fillers. The catalyst of Example 1 was used to crack a Santa Maria gas oil, a very corrosive high sulfur feedstock, under the following operating conditions:

 <Desc / Clms Page number 24>

   charge 1.5 volumes of oil per volume of catalyst per hour
 EMI24.1
 6 a temperature of approximately. 811C19 F, the tra2..te ,,: ent being carried out under atmospheric pressure, operate for 10 minutes with alternating regeneration. The following table shows the results
 EMI24.2
 tatas obtained C02Jl}; 8re ..- ti ve. the activated clay catalyst 1;

   Liaeià.e used cJ.a: Je- les y ::: S tes where, Ü tion: 3, the activity tests being carried out on a light gas oil from East Texas.
 EMI24.3
 



  Filtrol (Fe c = 2 IV): Cata13Ts.c1e ex.I 1.iàtr i <Fzi> "2;.> (4'e 0 = l el) ------------ ----------; --------------------: ----- ¯ ----------- Gasoline Coke Gas Gazoline Coke Gas ----------------------'-- ¯¯¯¯¯¯0¯¯¯¯'¯ -----'- --------' ----'----
 EMI24.4
 
<tb>: <SEP> test of <SEP> activity on <SEP> @
<tb>
 
 EMI24.5
 : catal.fresh (CAT-A) 34.8: 2.5: 4.3: 33.0 1.5: 3.0 '---------------------'-------- '----' ------' --------- '----'----
 EMI24.6
 
<tb> 'Santa <SEP> diesel <SEP>
<tb> Maria
<tb>
 
 EMI24.7
 1st round µ2: 10.8; 5.5 28 6.5: 3..3 4th round 27: Il.?: 7.0:

   OJ 6.5 2.9 Sixth round 24: 1.3.7: 6.6 d0: 6.4 3.1
 EMI24.8
 
<tb>
<tb>
<tb>
<tb>
<tb>: <SEP> test <SEP> activity of <SEP>: <SEP>
<tb>
<tb>
<tb>
<tb>
<tb> CAT-A <SEP> after <SEP> cracking <SEP>: <SEP>
<tb>
<tb>
<tb>
<tb>
<tb>: from <SEP> diesel <SEP> from <SEP> S.Maria <SEP> 18.33: <SEP> 4.9: <SEP> 5.8 <SEP> 35.0 <SEP>: 1.8 <SEP> 3.5
<tb>
<tb>
<tb>
<tb>
<tb> ----------------------------------------------- ----------------
<tb>
   Example VI The raw clay treated in this example was a kaolin clay from Putnam County, Florida, known as "Edgar EPK" which met the following analysis calculated on a dry product basis ( 105 C) and free from
 EMI24.9
 
<tb> sand.
<tb>
<tb>
<tb>



  Loss <SEP> at <SEP> on <SEP> calcination <SEP> 12.9
<tb>
<tb>
<tb> Si02 <SEP> 46.6 <SEP>) <SEP>
<tb>
<tb>
<tb> A1203 <SEP> 38.8 <SEP>) <SEP> SiO2 / Al203 = 1.2
<tb>
<tb>
<tb> Fe203 <SEP> 1.0
<tb>
<tb>
<tb> CaO <SEP> 0. <SEP> 44
<tb>
<tb>
<tb> MgO <SEP> 0.23
<tb>
<tb>
<tb>
<tb> TiO2 <SEP> 0.35
<tb>
<tb> Alkaline <SEP> metals <SEP> (in <SEP> oxide) <SEP> 0.52
<tb>
 The above clay was subjected in the raw state to the treatment.
 EMI24.10
 with excess H2S it l5jO- 2 for 2 hours. The clay was turning intensely black. After cooling she was
 EMI24.11
 washed with an equal volume of 15% hOl for 1/2 hour, the acid being changed four times. After decantation, washing and drying, the clay was calcined at 1050 F for 2 hours in air.

   Analysis for iron content was 0.07 Fe2O3.

 <Desc / Clms Page number 25>

 



  The activity of the catalyst obtained is compared in the following table with the original raw clay and with the same clay which received only treatment with% S04H2 (0.40 relative to the dry clay) for 8 hours and calcined under the same conditions as the products to be compared.



  -------------------------------------------------- ------------
 EMI25.1
 
<tb>
<tb> Clay <SEP> Edgar <SEP> Gasoline <SEP> Coke <SEP> Gas: <SEP> Density <SEP> gas
<tb>
 
 EMI25.2
 1 ------------------ 1 ------------ 1 -------- to ----- 1-- ------------
 EMI25.3
 
<tb> Gross <SEP> 14.5 <SEP> 2.7 <SEP> 4.0 <SEP>: <SEP> 0.57
<tb>
<tb> treated <SEP> to <SEP> acid <SEP> 27.8 <SEP> 1.8 <SEP> 4.4 <SEP> 1.36
<tb>
<tb> processed <SEP> to <SEP> H28 <SEP> and <SEP> 40. <SEP> 8 <SEP> 3.1 <SEP>: 10.2 <SEP>: <SEP> 1. <SEP> 46
<tb> washed <SEP> to <SEP> acid
<tb>
 Example VII - A sample of kaolin clay from the Eccles property, Putnam County, Florida, was treated with excess chlorine gas for 2 hours at 15009-F. Much of the iron was volatilized as ferric chloride. .

   On analysis, the initial iron content which was 1.4% Fe2O3 was reduced to 0.31%. The gasoline / gas and gasoline / coke ratios were markedly improved, the coke production being substantially the lowest. half of that obtained with clay from the same source, calcined in air at the temperature given above.



   The same clay was brought to 0.4% Fe2O3 by treatment with chlorine at 14009-F followed by acidic washing at room temperature. Tried in cracking a light gas oil under standard conditions, a yield of 34.7% by volume of gasoline was obtained, while the original clay calcined in air exhibited maximum gold activity. dre 25-26% gasoline.



   The initial Eccles clay responded to the following analysis by weight (containing 10-20% sand): 65.8 Si02, 32.4% A1203,
 EMI25.4
 1.4% Fe203, 0.23% CaO, 0.21% MgO, 0.69% TiO2.



  Example VIII.- Schools clay in pills after calcination for two hours in very dry air at 1500 F was treated with H2S at 1400 F for 2 hours, the treatment apparatus

 <Desc / Clms Page number 26>

 and its contents having been previously freed of air by flushing with nitrogen. The pills turn black.
 EMI26.1
 by an equal volume of Il'Cl tt lj% the pale color L p: 0,:.: res8 i-% .oiKe: ùt with departure of il2 ;: ".

   The product was washed with acid, washed several times with water, dried in an oven at moderate temperature, and finally calcined at 1400 F for 10 hours in the presence of 5% steam. . On analysis, the content of iron compounds was found to be 0.23% Fe2O3.
 EMI26.2
 



  The same clay initially treated with B2 at 1000s i 'for 2 hours but prepared otherwise as in the previous paragraph, exhibited 0.81% Fe2O3 on analysis.



   The following table compares the performance characteristics of treated and untreated clays:
 EMI26.3
 
<tb> Gasoline <SEP> Coke <SEP> Gas
<tb>
<tb>
<tb>
<tb> Clay <SEP> schools <SEP> raw <SEP>
<tb>
<tb> 1500 <SEP> F <SEP> (air) <SEP> 25.5 <SEP> 2.0 <SEP> 4.1
<tb>
<tb>
<tb> "<SEP> Schools <SEP> processed
<tb>
 
 EMI26.4
 1500S F acid (air) 32.9 2.6 6.1 t..cgxle Eccles'JI28 1000s F 31-i 1.7; iL.7 11 Il 11 MC09 F ;; 4.5 1. 5.6
 EMI26.5
 xe = sle m Ia .. - A kaolin clay from Q8 iriuron, India- na, having an iron content corresponding to è-i 0.95%} <\ e20) was treated with HSS at 1G-0-'¯ i 'for 2 hours followed by washing with 15% HCl for 5 days. After washing and drying, the product was calcined in air at 1050 F for 2 hours.

   The degree of improvement in cracking activity is indicated by the following comparison with the initial raw clay which underwent the pale calcination at. the air
 EMI26.6
 -------------------------------------------------- ------------
 EMI26.7
 
<tb> Catalyst <SEP> @ <SEP> Activity
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>: <SEP> Gasoline:

   <SEP> Coke <SEP> Gas <SEP> Density
<tb>
<tb>
<tb>
<tb>
<tb> volume <SEP> [<SEP> weight <SEP>% <SEP> weight <SEP> @ <SEP> Gas
<tb>
 
 EMI26.8
 -------------------------------------------------- ------- From ar, ilelinī¯¯¯¯1¯¯¯¯¯¯¯-7.4¯¯¯¯6.8 -. ¯-.46 tial (Fe203 = 0.95) ùxe; ple IV (Fe2Qµ = Q, lL) 1 µ9.5 / µ.4 1 LQ.µ Ù 1.50 ------------- ------------- 1 ---------- 1 -------- 1 ---------------

 <Desc / Clms Page number 27>

 Example X. Other typical examples of increasing gasoline yields and lowering coke after removal of iron by the method described emerge from the following comparisons:
 EMI27.1
 
<tb> Gasoline <SEP> Coke <SEP> Gas
<tb>
 
 EMI27.2
 Clay, commercial 4ilvahite
 EMI27.3
 
<tb> the <SEP> enabled <SEP> to <SEP> the acid <SEP> (a <SEP>:

   <SEP>
<tb>
<tb> <SEP> montmorillonite <SEP> from <SEP> Texas) <SEP>: <SEP> 42. <SEP> 4 <SEP> 6.4 <SEP> 12.1
<tb>
 
 EMI27.4
 -15 Argif, 6'30i = -éslses unit linked 44.0 4.5 Fe203 .15% rgil8 above modified 44.0¯-; 4.5 9.?
 EMI27.5
 
<tb> Clay <SEP> bentonite <SEP> from <SEP> Ponto-:
<tb>
<tb>
<tb> toc, <SEP> Miss. <SEP> activated <SEP> by
<tb>
<tb>
<tb> SO4H2 <SEP> (Example <SEP> IV <SEP> to) <SEP> 34.1 <SEP> 4.1 <SEP> 7.3
<tb>
<tb>
<tb> Fe203 <SEP> = <SEP> 2.88 <SEP>%
<tb>
<tb>
<tb> Clay <SEP> above <SEP> modified
<tb>
<tb>
<tb> (Example <SEP> IV <SEP> b <SEP>) <SEP>
<tb>
<tb>
<tb>
<tb> Fe203 <SEP> .11 <SEP> 41.

   <SEP> 4 <SEP> 3.4 <SEP> 8.9
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Raw <SEP> clay <SEP> kaolinite <SEP>
<tb>
<tb>
<tb>
<tb> '<SEP> from <SEP> from <SEP> Huron, India
<tb>
<tb>
<tb> Fe203 <SEP> = <SEP> .95 <SEP>% <SEP> 13.2 <SEP> 7.4 <SEP> 6.8
<tb>
<tb>
<tb> Clay <SEP> above <SEP> modified
<tb>
<tb>
<tb>
<tb> Fe203 <SEP> = <SEP>, Il <SEP>% <SEP> 39.5 <SEP> 3.4 <SEP> 10.3
<tb>
 
 EMI27.6
 n-¯¯ ------------------------ i --------- ¯ - ¯i - ¯¯ --- --- 1-¯¯¯¯¯¯¯ Example XI.- A 60-80% fraction of Texas st crude oil (API 27.6) was cracked in a static process using d 'a clay-based catalyst in pills prepared according to Example 1 (0.12% Fe2O3) under the following conditions:

   at a temperature of about 830 F and a gauge pressure of 5 to 10 lbs / sci.in, a flow rate of approximately 1, with 9 to 15% by weight of steam added to the load, 10 minutes of steam passage followed by regeneration.



   The above operation was repeated under substantially identical conditions except that the temperature was raised to 850 F. The results obtained are reported below.
 EMI27.7
 below: 830µF. g5'p -
 EMI27.8
 
<tb> 05 <SEP> + <SEP> gasoline <SEP> engine <SEP> 3659 <SEP> 90 <SEP>% <SEP> vol <SEP>% <SEP> 45.0 <SEP> 46.3
<tb>
<tb>
<tb>
<tb> cycle <SEP> load <SEP> vol. <SEP>% <SEP> 46. <SEP> 4 <SEP> 41. <SEP> 6
<tb>
<tb>
<tb>
<tb> 05 <SEP> + <SEP> recovery <SEP> liquid <SEP> vol. <SEP>% <SEP> 91.4 <SEP> 87.9
<tb>
<tb>
<tb>
<tb> C4 <SEP> and <SEP> gas <SEP> plus <SEP> light <SEP> weight <SEP>% <SEP>. <SEP> 10.

   <SEP> 4 <SEP> 14.0
<tb>
<tb>
<tb>
<tb> Coke <SEP> weight <SEP>% <SEP> 4.5 <SEP> 4.5
<tb>
<tb>
<tb>
<tb> 10 <SEP> # <SEP> octanes <SEP> of the <SEP> gasoline-engine
<tb>
<tb>
<tb>
<tb> CFR-MM <SEP> (clear) <SEP> 80.5 <SEP> 80.2
<tb>
<tb>
<tb>
<tb>
<tb> CFR-R <SEP> (clear) <SEP> 89.0 <SEP> 89.9
<tb>
 

 <Desc / Clms Page number 28>

   Obviously, many (the modifications and variations of the invention as indicated in the foregoing can be made without departing from its spirit and the views and for this reason only the limitations indicated in the appended claims will be imposed. @s. devendications.



   1 / A process for converting hydrocarbons to gasoline of improved quality which comprises the treatment of the hydrocarbons under catalytic transformation conditions in contact with a catalyst comprising a molten clay mass of which. at least most of the initial isomorphic iron content has been removed.


    

Claims (1)

2 / The method of claim 1 wherein the catalyst employed has a total content of compounds of the corresponding iron, less than 0.4% Fe2O3. 3 / A method according to claims 1 and 2, characterized in that the catalyst contains, calculated on a dry basis, not less than 93% of silica and alumina by weight, the remainder of the composition mainly comprising magnesia. , the ratio of silica to alumina not exceeding 5: 1. 4 / A method according to claims 1 to 3, wherein the catalyst is obtained from a clay of the montmorillonite type. 5 / A method according to claim 4, characterized in that the montmorillonite type clay has been activated with acid 6 / A method according to claims 1 and in which the catalyst is derived from a kaolindique clay. 7. A method according to claims 1 to 6, in which the catalyst has been calcined before use in the process of converting hydrocarbons. 8 / A method according to claims 1 to 7, in which normally liquid hydrocarbons are subjected ini- <Desc / Clms Page number 29> primarily to the conversion to the vapor state and the conditions involving pressure, temperature and a rate of contact between the hydrocarbon and the catalyst employed in the process are selected from the conditions suitable for effecting the cracking of hydrocarbons normally liquid. 9 / A method according to claim 8, characterized in that the initial hydrocarbons subjected to the conversion consist of oils having a higher boiling range than gasoline, the oils of which are cracked during the process. 10 / A method according to claims 8 and 9, wherein the initial hydrocarbons subjected to the conversion have a high content of sulfur compounds, and the catalyst employed contains less than 0.2% Fe2O3. The process according to claims 1 to 10, wherein the catalyst employed is prepared by acid washing of a modified clay containing iron sulfide. 12 / A process according to claims 1 to 3 and 7 to 11, in which the catalyst employed is an acid activated montmorillonite clay, from which at least a portion of the residual iron compounds remaining after 1 has been removed. Acid activation by a treatment comprising contact at elevated temperature with a gaseous iron reactant to form iron salts. 131 Process according to claims 1 to 12, in which the catalyst employed has a CAT-A activity, as defined in the above, greater than 30% gasoline. 14 / A process for the catalytic conversion of hydrocarbons at high temperature using catalysts based on clay, characterized in that the catalyst employed is derived from clay which has been modified by treatment with hydrogen sulphide at high temperature followed by acid washing. <Desc / Clms Page number 30> 1 @ / A method according to claim 14, wherein the clay is of the acid activated montmorillonite type. 16 / A method according to claim. 14 in which the clay is kaolin. 17 / A method according to claims 6 and 16, wherein the catalyst employed contains a total of iron compounds corresponding to less than 0.8% and preferably less than 0.4% of Fe2O3. 18 / A method according to claim 17, characterized in that the catalyst @e contains not more than 70% silica and at least 25% alumina. 19 / A process for the conversion of hydrocarbons to better quality gasoline, essentially as described. 20 / Hydrocarbon products including gasoline when EMI30.1 that they are obtained by the claimed p-rocédc. oi- n ni .. "11-"