US2891003A - Method of hydrodesulfurizing olefinic gasoline using an iron oxide-chromium oxide catalyst - Google Patents

Description

2,891,003 Patented June 16, 1959 METHOD OF HYDRODESULFURIZING OLEFINIC GASOLINE USING AN IRON OXIDE-CHROMIUM OXIDE CATALYST Michael C. Chervenalr, Trenton, Percival C. Keith, Peapack, and Helmut R. Pichler, Trenton, N.J., assignors to Hydrocarbon Research, Inc., New York, N.Y., a corporation of New Jersey No Drawing. Application March 15, 1954 Serial No. 416,446

9 Claims. (Cl. 208--216) This invention relates to the treatment of hydrocarbon oils and is more particularly concerned with the treatment of raw cracked gasoline fractions. The invention is concerned primarily with the treatment of raw cracked gasoline fractions to produce finished gasoline of commercial motor gasoline likewise required that it pass an existent gum test, in accordance with ASTM method D38l50, in which the gasoline must show less than mg. of gum per 100 ml. In addition, it is highly desirable that commercial motor gasoline meet the storage stability requirements set forth in ASTM methods D910- 52T or D525-49. Finally, the demands of modern high compression engines make necessary the production of motor gasoline possessing a high octane rating, usually determined as clear research octane number in accordance with ASTM method D908-48T. In recent years, motor gasolines sold in many U.S. cities have had research octane ratings of approximately 83 and 90 for regular and premium gasolines, respectively, with such gasolines containing anaverage of 1.35 and 1.75 cc./gal., respectively, of tetraethyl lead.

In modern petroleum refining practice, it is highly advantageous to convert part or all of the higher boiling fractions of the crude oil to materials boiling in the gasoline range. This is effected by processes which involve the cracking of the higher boiling hydrocarbons into hydrocarbons boiling in the gasoline range. However, in many cases, the gasoline fraction which is produced by cracking (hereinafter referred to as raw gasoline) requires further processing to provide a commercially acceptable product having a sulfur content, storage stability and octane number within the above specified limits. Various processes have been proposed for treating such raw gasoline fractions to bring them within the desired specification limits, and some of these processes have been commercially used with varying effectiveness.

While sulfur compounds are found in varying amounts in petroleum crudes or fractions, the amount of such compounds often exceeds a value corresponding to 1.0% by weight of sulfur. When such a crude or crude fraction is cracked, the raw gasoline product thereby obtained may not meet the above limits with respect to sulfur content. Furthermore, the sulfur compounds in the raw gasoline often exist as thiophenes and compounds of similar cyclic structure. Such cracked raw gasolines are generally of moderate to high octane number, containing 10 to 50% by volume of aromatic hydrocarbons and at least 20% by volume of olefins. Known methods for removing cyclic sulfur compounds bring about the destruction or conversion of some of these unsaturated hydrocarbons. For example, when hydrogenation at relatively high pressures and relatively low temperatures is employed, the olefins present in the cracked gasoline are completely hydrogenated to paraffins, i.e.

It is Well known that such paraflins have clear research octane numbers which are as much as 40 octane numbers lower than the corresponding olefins from which they were formed. Thus, such treatment of a raw cracked gasoline fraction produces a finished gasoline which is generally of appreciably lower clear research octane number than the raw gasoline, and which is in all cases of lower clear research octane number than would have been obtained if said olefins had not been hydrogenated. Where the cracking operation produces a raw gasoline which satisfies octane number requirements without the addition of tetraethyl lead, e.g., above 83 clear research octane number, such utilization of conventional hydrogenation treatment to remove cyclic sulfur compounds results in a finished gasoline which is of considerably re duced clear octane number and which consequently requires significant quantities of anti-knock additives to achieve octane requirements. Thus, the principal problem which these cracked raw gasoline fractions of high octane number and high sulfur content present is the reduction of sulfur content to commercially acceptable limits without adverse effect upon the clear research octane number. Similarly, when such cracked raw gasoline fractions are relatively unstable, it is necessary to increase their stability to the desired extent without adverse efiiect upon the other properties of the gasoline. These are problems which have not been solved in a satisfactory and elficient manner by prior processes for treating raw gasoline.

A principal object of the present invention is to provide a process for treating raw gasoline fractions containing at least 20% by volume of olefins and more than 0.1% by weight of sulfur as thiophenic or other cyclic sulfur compounds, which process will eliminate a substantial portion of said sulfur compounds, while maintaining the major portion of said olefins.

It is a further important object to provide a process for treating said raw gasoline fractions, which will eliminate a substantial portion of said sulfur compounds, while increasing or at least maintaining the octane ratings of said raw gasolines.

It is another object of the invention to provide a process of the character indicated which is also effective simultaneously to increase the stability of such raw gasoline fractions.

Still another object is to provide an improved cracked raw gasoline treating process which avoids the shortcomings of treating processes heretofore proposed.

It is a feature of the invention that cracked raw gasoline is treated at an elevated temperature and at a me determined hydrogen partial pressure in the presence of a material having catalytic activity to convert refractory cyclic sulfur bodies into readily separable compounds, and gum-forming bodies into stable hydrocarbons. This treatment does not significantly decrease the clear research octane number of the raw cracked gasoline, even when the octane number exceeds 80. In many cases, the process of this invention increases the octane number. Thus, the application of this process to raw lgasolines of clear research octane number exceeding 80. makes it possible to meet commercial octane requirements without the addition of ani-knock agents.

In accordance with the invention, a cracked raw gasoline fraction containing over 0.1% by weight of sulfur as thiophenes and other cyclic compounds, and containing at least 20% by volume of olefins, is introduced, to-

gether with hydrogen, into a treating zone maintained at a temperature of 750 to 1000".F., preferably at a temperature of about 800 to 950? F., in contact with particulate iron-chromium catalyst of the character hereinbelow described. The total pressure in the treating zone and the introduction of hydrogen and raw gasoline are controlled in known manner to provide a hydrogen partial pressure of 50 to 250 p.s.i. (pounds per square inch), preferably 50 to 150 p.s.i. The total pressure of the system may vary over a relatively wide range, but it is generally preferred to use a total pressure not exceeding about 800 p.s.i.g. (pounds per square inch gage). The iron-chromium catalyst employed in the treating zone is derived from a mixture of iron and chromium oxides in which mixture the chromium oxide is the minor component. In most instances, the chromium oxide is in the range of 0.2 to 20% by weight of the catalytic oxide mixture, 0.5 to 5% by weight of chromium oxide being frequently optimum. Such catalytic mixtures have been readily prepared by the co-precipitation of the iron and chromium oxides in the plus three valence states.

It is noteworthy that the catalyst of this process does not require a support or carrier. In fact, iron-chromium oxide mixtures supported by carriers have been found less effective than the unsupported oxides.

It is an outstanding advantage of this invention that the hydrogen supplied to the treating zone does not need to be in concentrated or purified form. Rather, the economic attractiveness of the process stems in large part from the fact that commonly available hydrogen-containing gases having such components as the carbon oxides, methane and steam may be utilized. In prior desulfunzation processes, such gaseous components have been product gas rich in hydrogen, carbon oxides, methane and steam. The hydrocracking process converts heavy oils to high yelds of raw gasoline of high octane number.

This raw gasoline is highly olefinic and contains gumforming bodies and sulfur compounds, including those of the refractory thiophenic type. The process of this invention is particularly suited for the stabilization and desulfurization of hydrocracked raw gasoline since the by- :product gas of the hydrocracking operation will satisfy the hydrogen requirements of the. process without necessitating any refinement of the gas or any supplementation of its hydrogen content from an extraneous source.

Another recent development which highlights the economic attractiveness of the present invention is the partial combustion of hydrocarbons with high-purity oxygen .to produce a gas comprising hydrogen and carbon monoxide as the predominant components. U.S. Patent 2,491,-

518 of E. W. Riblett discloses the production of such gas. Today, the partial combustion of natural gas with oxygen obtained by the liquefaction and rectification of air offers in many localities the cheapest source of hydrogen. Consequently, olefinc raw gasolines can now be desulfurized and stabilized against gum formation very economically by this invention utilizing as the hydrogen-containing gas the product of the partial combustion process without any intermediate treatment.

Interestingly enough, when the hydrogen-containing gas fed to the desulfurization zone also contains carbon monoxide and water vapor in appreciable quantities, the tail gas of this process may be richer in hydrogen than the gas supplied thereto even though hydrogen is consumed or taken up by the sulfur compounds and gumforming bodies of the raw gasoline undergoing treatment. This is possible in the present process because the ironchromium oxide catalyst iscapable of promoting simultaneously desulfurization and the water-gas shift reaction:

There is reason to believe that treating raw gasoline pursuant to this invention with gas that undergoes the watergas shift reaction is particularly desirable because nascent hydrogen will more readily attach the sulfur and gumtforming compounds.

The hydrogen-containing gas will preferably comprise at least about 20% by volume of hydrogen in order to avoid the necessity of passing excessively large amounts of gas through the reaction zone to provide the desired hydrogen partial pressure of 50 to 250 p.s.i. and in order to avoid the necessity of raising the total pressure of the system to a high value. The amount of hydrogen supplied to the treating or reaction zone generally falls in the range of 1000 to 5000 standard cubic feet per barrel of raw gasoline, approximately 2000 standard cubic feet per barrel being in many instances adequate.

Treatment of the cracked raw gasoline. in the reaction zone under the specified conditions is carried out to an extent sufllcient to reduce the sulfur content of the raw gasoline and to improve its stability to the desired degree. Advantageously, the desired reaction is insured by employing a raw gasoline feed rate in the range of 0.3 to 3, preferably 0.5 to 1.5, volumes of liquid per hour per volume of catalyst.

The term gasoline fraction" as herein used has its conventional meaning, viz., hydrocarbon fraction boiling Within the temperature range of 90 to 400 F., although it will be apparent that the treating process of this invention is applicable to hydrocarbon fractions in which ma,- terial boiling withinthe gasoline range comprises the predominant portion of the fraction.

Cracked raw gasoline fractions from various sources are advantageously treated in accordance with the process of the invention but the improved process is of particular value, as already mentioned, in reducing the sulfur content of hydrocracked raw gasoline fractions of relatively high octane number, e.g., clear research octane numbers of about to 90, containing substantial quantities of mono-olefins. Frequently, the olefins amount to at least 30% by volume of the raw gasoline. As previously pointed out, the present process is effective to remove even large proportions of sulfur bodies, including thiophenes and similar cyclic compounds, without any appreciable change of the high octane number of the raw gasoline. In some cases the octane number is not lowered by more than one or two units, whereas in other cases it is increased by such an amount.

Without tying the invention to any particular theory of operation, the process appears to involve the following types of reactions which take place more or less simultaneously. Thiophenes and related cyclic sulfur compounds are converted to normally gaseous sulfur compounds like hydrogen sulfide, and diolefins are con.- verted to mono-olefins. At the same time, aromatic hydrocarbons are not affected and only mild hydrogenation of mono-olefins takes place so that the excellent antiknock properties of the raw gasoline are not impaired.

Under the conditions of this process there is such limited polymerization or other degradation of the gasoline hydrocarbons that the deposition of carbo- 'naceous matter on the catalyst may be held to less than about 0.5% by weight of the raw gasoline and often to less than about 0.1%. Thus, the catalyst may be used for long periods without regeneration to effect removal of the carbonaceous deposit. 'For instance, operating the process with a fixed bed of iron-chromium oxide catalyst and a raw gasoline feed rate of 1 liquid volume per hour per volume of catalyst, the on-stream time will be over 1 hour and may be as much as a day; regeneration of the catalyst after 6 to 9 hours of operation will probably be adequate in most cases. At the same time, no highboilinghydrocarb'ons are formed so that the treated gasoline does not require fractionation to separate out any polymers or heavy hydrocarbons. The treated gasoline wiligenerally amount to at least about 97% by volume of the raw gasoline.

The effluent from the treating zone will contain vapors of the gasoline hydrocarbons admixed with more volatile compounds including readily removable sulfur compounds formed by the breakdown of thiophenes and like refractory sulfur compounds in the reaction zone.

The finished gasoline fraction recovered from the reaction effluent is of low sulfur content, high stability and high octane number and meets the specifications for commercial motor gasoline notwithstanding the presence of a substantial quantity of sulfur compounds and diolefins originally in the cracked raw gasoline. The sulfur content of the finished gasoline can be reduced to below 0.1% by weight by the present process, as well as below the 0.3% by weight level presently accepted for marketable motor gasoline.

The particular apparatus used for the process and the particular method of regenerating the catalyst form no part of the present invention and any convenient apparatus and method of catalyst regeneration may be employed. In regenerating the catalyst care must be taken, however, in accordance with commercial regeneration techniques, to avoid the use of temperatures which destroy or adversely alfect the catalyst. In the regeneration of the catalyst of the present process, temperatures in excessof 1100 F. are generally to be avoided.

In order to facilitate the maintenance of the desired temperature in the reaction zone, the raw cracked gasoline to be treated is advantageously preheated to a temperature of 400 to 800 F., preferably about 500 to 700 F., before being fed into the reaction zone. At such temperatures the gasoline is at least partially vaporized. The hydrogen-containing gas may also be preheated to about the same temperature as the gasoline.

For a further understanding of the invention, reference is made to the following specific examples which are intended as illustrative and not limitative of the process.

Example 1 A raw gasoline obtained by vis-breaking a Kuwait residuum contains 1.1% by weight of sulfur largely in the form of refractory compounds and 25% by volume of olefins.

This raw gasoline and hydrogen-containing gas are brought into contact with a catalyst composed of 95% by weight of iron oxide and 5% by weight of chromium oxide, the mixed oxides having been coprecipitated. The gas is derived by the partial combustion of natural gas with oxygen at a temperature of about 2400 F. and has an approximate composition on a volume basis, after quenching with water to 900 F.: 36% H 21% CO, 2% C 1% N and 40% H 0. This gas is charged to the reaction zone at a rate corresponding to 1800 standard cubic feet of hydrogen per barrel of raw gasoline charged therewith to maintain a hydrogen partial pressure of about 100 p.s.i. in the'reaction zone. The space velocity of the raw gasoline is 1.0 liquid volume per hour per volume of catalyst. The reaction zone is maintained at a temperature of 900 F. The finished gasoline recovered from the reaction effiuent; amounts to 98% by volume of the raw gasoline.

The improvement, of the gasoline achieved by the process is evidentfrlom a comparison of its properties, before and after treatment:

Example 2 The hydrocrac king of Kuwait residuum yields a raw gasoline containing about 42% by volume of olefins and a by-product gas which contains about 23% by volume of hydrogen, 12% carbon monoxide and 28% steam. The remainder of the gas is largely carbon dioxide and gaseous hydrocarbons, principally methane.

This gasoline of high thiophenic sulfur content together with the by-product gas is made to contact a catalyst composed of 97% by weight of iron oxide and 3% by weight of chromium oxide. The reaction conditions include a hydrogen partial pressure of p.s.i., a temperature of 970 F. and a raw gasoline space velocity of 0.9 liquid volume per hour per volume of catalyst. The yield of finished gasoline corresponds to 96% by volume of the raw gasoline.

The proprties of the gasoline, before and after treatment, are as follows:

Raw Finished Gasoline Gasoline Sulfur Content, wt. Percent 0.8 0.2 Octane Number, OFRR Clear 88.0 86.6 Octane Number, OFRR+3 cc. TEL/ga 92.0 93. 9 Oxygen Induction Time, minutes 135 435 ASTM Gum Content, nag/ m1 75 2 Example 3 A raw, cracked gasoline containing 0.18% by weight of sulfur in the form of refractory compounds and about 45% by volume of olefins is brought into con tact with a hydrogen-containing gas and a catalyst consisting of 99.2% by weight of iron oxide and 0.8% by weight of chromium oxide. The hydrogen-containing gas consists essentially of hydrogen, carbon monoxide and steam in the respective volume proportions of 221:2.4 and is supplied to the reaction zone at a rate of 4,000 standard cubic feet per barrel of raw gasoline charged therewith to maintain a hydrogen partial pressure of about 100 p.s.i. in the reaction zone. The space velocity of the raw gasoline is one liquid volume per hour per volume of catalyst and the reaction tempera ture is maintained at 925 F. 'The finished gasoline recovered from the reaction effluent amounts to 98.5% by volume of theraw gasoline.

The properties of the gasoline, before and after treatment, are as follows:

Raw Finished Gasoline Gasoline Sulfur Content, wt. Percent 0.18 0.02 Octane Number, CFRR Clear 92. 0 89. 5 Octane Number, CFRR-l-S cc. TEL/gal 97. 7 97. 5 Oxygen Induction Time, minutes 240 420 ASTM Gum Content, mgJiOO m1 6. 4 0.2

7 reduction and thus supply the catalyst to the reaction in a state more nearly like that attained during operation of the process when the catalyst reaches a high level of activity.

It is to be observed that, in addition to the removal gasolines.

In view of the various modifications of the invention which will occur to those skilled in the art upon consideration of the foregoing disclosure without departing from the spirit or scope thereof, only such limitations should be imposed as are indicated by the appended claims.

What is claimed is:

1. A vapor-phase process for desulfurizing a highly olefinic hydrocarbon fraction, which comprises bringing hydrogen and a vaporized hydrocarbon fraction containing more than 1% by weight of sulfur in the form of refractory sulfur compounds and more than 20% by volume of olefins imparting to said hydrocarbon fraction a high octane number into contact with an ironchromium'oxide catalyst comprising chromium oxide in the range of 0.2 to 20% by weight of the catalytic oxide mixture in a reaction zone maintained at a temperature in the range of 750 to 1000 F., effecting reaction between said hydrogen and said vaporized hydrocarbon fraction during contact with said catalyst to the extent that there is a net consumption of hydrogen without hydrogenation of at least a major portion of said olefins, passing said hydrocarbon fraction through said reaction zone at a space velocity in the range of about 0.3 to 3 liquid volumes per. hour pervolume of said catalyst,

maintaining the partial pressure of hydrogen in said reaction zone in the range of 50 to 250 p.s.i., and recovering from the resulting vaporized reaction eflluent a highly olefinic hydrocarbon fraction containing less than 0.3% by weight of sulfur and at least a major portion of said olefins and having a high octane number.

2. A vapor-phase process for desulfurizing a highly olefinic hydrocarbon fraction, which comprises bringing hydrogen and a vaporized hydrocarbon fraction containing more than 0.1% by Weight of sulfur in the form of refractory sulfur compounds and more than 30% by volume of olefins imparting to said hydrocarbon fraction a high octane number into contact with an ironchromium oxide catalyst comprising chromiumoxide in therange of 0.2 to 20% by weight of the catalytic oxide mixture in a reaction zone maintained at a temperature in the range of 800 to 950 F., effecting reaction between said hydrogen and said vaporized hydrocarbon fraction during contact with said catalyst to the extent that there is a net consumption of hydrogen Without hydrogenation of at least a major portion of said olefins, passing said hydrocarbon fraction through said reaction zone at a space velocityin the range of about 0.3 to 3 liquid volumes per hour per volume of said catalyst, maintaining the partial pressure .of hydrogen in said reaction zone in the range of 50 to 250 p.s.i., and recovering from the resulting vaporized reaction effiuent ahighly olefinic hydrocarbon fraction containing less than 0.1% by weight of sulfur and at least a major portion of said olefins and having a high octane number.

3. A vapor-phase process for desulfurizing a highly olefinic gasoline fraction,'which comprises bringing hydrogen and a vaporized gasoline fraction containing more than 0.3% by weight of sulfur in the form of refractory sulfur compounds and more than 30% by volume of olefins and having a clear research octane number of at least about 80 into contact with an ironchromium oxide catalyst comprising chromium oxide in the range of 0.2 to 20% by weight of the catalytic oxide mixture in a reaction zone maintained at a temperature in the range of 800 to 950 F., effecting reaction between said hydrogenand said vaporized gasoline fraction during contact with said catalystto the extent that there is a net consumption of hydrogen without hydrogenation of at least major portion of said olefins, passing said gasoline fraction through said. reaction zone at a space velocity in the range of about 0.3 to 3 liquid volumes per hour per volume of said catalyst, maintain ing the partial pressure of hydrogen in said reaction zone in the range of 50 to 250 p.s.i., andrecovering from the resulting vaporized reaction efiluent a highly olefinic gasolinefraction containing less than 0.3% by weight of sulfur and at leasta major portion of said olefins and having a clear research octane number of at least about 80. i

4. A vapor-phase process according to claim 3 wherein the iron-chromium oxide catalyst is derived by the co-precipitation of the iron and chromium oxides, and{ the hydrogen partial pressure is in. the range of 50 to p.s.i.

5. A vapor-phase process according to claim 3 wherein the hydrogen supplied to the reaction zone is admixed with a substantial quantity of a gas selected from the group consisting of carbon monoxide, carbon dioxide, water vapor and mixtures thereof.

6. A vapor-phase process for refining a highly olefinic gasoline, which comprises bringing hydrogen and a vaporized raw gasoline containing an appreciable quantity of troublesome foreign matter of the class of refractory sulfur compounds and "gum-forming bodies and containing more than 20% by volume of olefins, said raw gasoline having a clear research octane number .of at least about 80, into contact with aniron-chromium oxide catalyst comprising chromium oxide in the range of 0.2 to 20% by weight of the catalytic oxide mixture in a reaction zone maintained at a temperature in the range of 800 to 950 F., effecting reaction between said hydrogen and said vaporized raw gasoline during contact with said catalyst to the extent that there is a net consumption of hydrogen without hydrogenation of at least a major portion of said olefins, passing said raw gasoline through said reaction zone at a space velocity in the range of about 0.3 to 3 liquid volumes per hour per volume of said catalyst, maintaining the. partial pressure of hydrogen in said reaction zone in the range of 50 to 150 p.s.i., and recovering from the resulting vaporized reaction eflluent a highly olefinic finished gasoline substantially free of troublesome foreign matter and containing at least 20% by volume of said olefins and having a clear research octane number over 80.

7. A vapor-phase process accordingto claim 6 wherein the iron-chromium oxide catalyst isderived by the co-precipitation of the iron and chromium oxides, the chromium oxide being in the range of 05 to 5%, by weight of the co-precipitated oxides.

8. A vapor-phase process according to claim 7 wherein the gasoline passes through the reaction zone at a space velocity in the range of about 0.5 to 1.5 liquid volumes per hour per volume of catalyst.

9. A vapor-phase process according to claim 7 wherein the raw gasoline contains more than 30% by volume of olefins and the hydrogen supplied to the reaction zone is admixed with substantial quantities of carbon monoxide and water vapor.

References Cited in the file of thispatent UNITED STATES PATENTS 2,398,919 Byrns Apr. 23, 1946 2,500,146 Fleck et a1. Mar. 14, 1950 2,608,521 I-Ioog Aug. 26, 1952 2,658,858 Lang et al. Nov. 10, 1953 2,671,754 De Rosset et a1. Mar. 9, 1954 2,774,718 Johnson et al. 1' Dec; 18,1956 2,774,719- Johanson Dec. 18, 1956

Claims (1)

1. A VAPOR-PHASE PROCESS FOR DESULFURIZING A HIGHLY OLEFINIC HYDROCARBON FRACTION, WHICH COMPRISES BRINGING HYDROGEN AND A VAPORIZED HYDROCARBON FRACTION CONTAINING MORE THAN 1% BY WEIGHT OF SULFUR IN THE FORM OF REFRACTORY SULFUR COMPOUNDS AND MORE THAN 20% BY VOLUME OF OLEFINS IMPARTING TO SAID HYDROCARBON FRACTION A HIGH OCTANE NUMBER INTO CONTACT WITH IRONCHROMIUM OXIDE CATALYST COMPRISING CHROMIUM OXIDE IN THE RANGE OF 0.2 TO 20% BY WEIGHT OF THE CATALYTIC OXIDE MIXTURE IN A REACTION ZONE MAINTAINED AT A TEMPERATURE IN THE RANGE OF 750 TO 1000*F., EFFECTING REACTION BETWEEN SAID HYDROGEN AND SAID VAPORIZED HYDROCARBON FRACTION DURING CONTACT WITH SAID CATALYST TO THE EXTENT THAT THERE IS A NET CONSUMPTION OF HYDROGEN WITHOUT HYDROGENATION OF AT LEAST A MAJOR PORTION OF SAID OLEFINS, PASSING SAID HYDROCARBON FRACTION THROUGH SAID REACTION ZONE AT A SPACE VELOCITY IN THE RANGE OF ABOUT 0.3 TO 3 LIQUID VOLUMES PER HOUR PER VOLUME OF SAID CATALYST, MAINTAINING THE PARTIAL PRESSURE OF HYDROGEN IN SAID REACTION ZONE IN THE RANGE OF 50 TO 250 P.S.I., AND RECOVERING FROM THE RESULTING VAPORIZED REACTION EFFLUENT A HIGHLY OLEFINIC HYDROCARBON FRACTION CONTAINING LESS THAN 0.3% BY WEIGHT OF SULFUR AND AT LEAST A MAJOR PORTION OF SAID OLEFINS AND HAVING A HIGH OCTANE NUMBER.