US3063933A - Process for removing sulfur and nitrogen from a conversion feed stock with return ofnitrogen to conversion product - Google Patents

Description

Nov. 13, 1962 H. c. MEINERS PROCESS FOR REMOVING SULFUR AND NITROGEN FROM A CONVERSION FEED STOCK WITH RETURN OF NITROGEN T0 coNvERsIoN PRODUCT Filed May 5. 1959 PRODUCT 6 4504 //VE 14050,? BER REFOR/l/ER INVENTOR.

AEA A) c. Alf/WERE BM C (-1- ite rates fiQC 3 063,933 PRGCESS FOR REMOilNG ULFUR NHRO- GEN FROM A CGN'VERSIGN FEED STOCK WKTH RETURN OF NITROGEN T CONVEEON PRODUCT This invention relates to the refining of hydrocarbon mixtures of the gasoline boiling range, and in particular concerns an improved process for the conversion of nitrogenous low antiknock rating fuels to high antiknock rating fuels.

Modern premium automotive and aviation fuels used in high compression engines ordinarily require an antiknock rating of 98 to 100 as a minimum. Considerable quantities of such premium fuels are produced from low grade gasoline boiling range materials by catalytic reforming or other hydrocarbon conversion process to obtain fuels or blending stocks of high antiknock rating. However, many of such catalytic conversion processes are detrimentaily affected by the presence of the organic compounds of sulfur and nitrogen in the feed stock; consequently, it is conventional practice to pretreat the feed stocks, usually with hydrogen in the presence of a cobalt molybdate catalyst, to effect desulfurization and denitro genation. characteristically, the treated feed stock is substantially completely free of sulfur, but contains a small residual quantity of organic nitrogen compounds which, even though present only to an extent of 220 p.p.m., have a decidedly adverse efiect upon the subsequent catalytic conversion operation. This adverse effect is most pronounced when the conversion operation takes the form of a reforming operation employing a noble metal catalyst, particularly, a halide-promoted platinum reforming catalyst, although it is encountered to some extent in other types of conversion, e.g., isomerization, cracking, etc.

It is accordingly an object of this invention to provide an improved process for upgrading nitrogenous hydrocarbon mixtures of the gasoline boiling range.

Another object is to provide an improved process for denitrogenating hydrocarbon mixtures which are subsequently subjected to a catalytic conversion operation of a type which is adversely affected by the presence of organic nitrogen compounds in the feed stock.

A further object is to provide an improved hydrocarbon reforming process comprising, as an integral step thereof, a denitrogenation operation carried out on the feedstock prior to contacting the same with a reforming catalyst.

Other and related objects will be apparent from the following detailed description of the invention and various advantages not specifically referred to herein will be apparent to those skilled in the art upon employment of the invention in practice.

I have now found that the foregoing objects and their attendant advantages can be realized in an improved combination refining process in which a nitrogenous, relatively low octane gasoline is treated with a selective adsorbent for the removal of residual nitrogen compounds, upgraded in a catalytic conversion step to increase the octane rating, and the upgraded gasoline is then recycled to desorb the nitrogen compounds that were adsorbed on the adsorbent in the adsorption step of the process. The adsorbent is thus returned to a lean state for re-use in the next succeeding cycle of operation. The high octane gasoline product of the process is a premium fuel particularly suitable for high compression engines.

Considering now the process of the invention in detail,

it is generally applicable to gasoline-boiling range hydrocarbons containing normally incident amounts of organic nitrogen compounds as contaminants. Usually, of course, such hydrocarbon mixtures are of petroleum origin, although they may be derived by the processing of oilshale, bituminous sands, coal and the like, and are those which have been previously treated for the removal of organic sulfur compounds. In accordance with a preferred embodiment of the invention, a sulfurand nitrogen-containing hydrocarbon mixture is first treated to remove substantially all of the sulfur compounds and part of the nitrogen compounds, and the desulfurized product is then denitrogenated and upgraded as mentioned above.

The adsorption step of the process is effected by contacting the nitrogenous feed stock with a natural or synthetic granular solid crystalline Zeolitic metallo alumino silicate activated by partial dehydration and having substantially uniform pores between about 7 A. and about 13 A. in diameter to effect removal of the organic nitrogen compounds. These zeolitic adsorbents, commonly referred to as molecular sieves, exert a high preferential adsorption for the nitrogen compounds present in the feedstock, and cannot be substituted with other known granular adsorbents, such as silica gel, activated aluminum oxide, activated carbon and the like.

Certain naturally occurring minerals can be heated to dehydrate the molecules and obtain molecular sieve adsorbents which can be employed in accordance with the invention. However, we greatly prefer to use the synthetic materials which are conveniently prepared by heating suitable quantities of alumina and silica with an excess of sodium hydroxide and thereafter washing out the excess to obtain a synthetic crystalline zeolitic sodium alumino silicate having a pore diameter of about 13 A. and having a typical approximate composition corresponding to [6Na O-6Al O l5SiO on a water-free basis. The uniform pore diameter of this product can be altered by exchanging part of the sodium cation with other atoms. For example, such a product can be heated with'a concentrated solution of a calcium salt, e.g., calcium chloride at 20 C. to 175 C., washed with water to remove excess calcium chloride and thereafter partially dehydrated by heating to obtain a calcium sodium alumino silicate having a pore diameter of about 10A. and having a typical average molecular structure on a water-free basis corresponding to Other cations such as magnesium, strontium, barium, potassium and the like can be employed instead of calcium. While any molecular sieve having a pore diameter between about 7 A. and about 13 A. can be employedin accordance with the invention, it is preferred to use the 10 A. calcium sodium alumino silicate and the 13 A. sodium alumino silicate referred to above which are available commercially under the trad-e names Molecular Sieves 10X and Molecular Sieves 13X and which usu ally Eontain substantial amounts of inert binder materials. British Patent 777,233 gives further details on the properties and mode of preparation of the molecular sieves of the present class.

The optimum particle size of the adsorbent will depend upon the manner in which it is used in the process, i.e., as a fixed compact bed, a moving compact bed, a fluidized bed, etc., but is usually between about 2 and about 400 mesh, preferably between about 4 and about 30 mesh for fixed and moving compact beds and between about and about 300 mesh for fluidized beds.

The adsorbent is preferably employed in the form of a dense compact fixed or moving bed which is alternately contacted with the feed and then desorbed. In the simplest embodiment of the invention the adsorbent is employed in the form of a single static bed in whichcase the process i only semi-continuous. Preferably, a set of two or more static beds is employed in fixed bed contacting with appropriate valving so that the feed stream is passed through one or more adsorbent beds while the desorption is carried out in one or more other beds in the set.

The direction of ilow during adsorption and desorption can be either up or down through the adsorbent but preferably the adsorption is carried out in one flow direction and the desorption in the other. Any of the conventional apparatus employed in static bed fluid-solids eontacting can be used. A moving compact bed of an adsorbent has a greater separation eiiiciency than a fixed compact bed of the same size because of the ability of the former to provide reflux.

In carrying out the adsorption operation, the feed mixture can be handled in either the vapor or liquid phase. However, vapor phase adsorption is greatly preferre In general, the temperature is between about F. and about 800 F., preferably between about 100 F. and about 700 F., and the pressure is between about atmospheric and about 1,000 p.'s.i.g., preferably between about 250 p.s.i.g. and about 500 p.s.i.g. When the adsorption step is preceded by a catalytic desulfurization operation, as hereinafter more fully explained, it is most suitably carried out at or near the operatingconditions of such desulfurization operation; otherwise, it is convenient to operate under conditions at least close to those employed in the subsequent conversion operation.

. The immediate products of the initial adsorption step are an unadsorbed or raifinate phase which is substantially nitrogen-free and a solid rich adsorbent containing an adsorbate rich in the organic nitrogen components of the feed mixture. The solid adsorbent and the unadsorbed phase are separated, and the latter is passed to the catalytic conversion step as feed therefor. Since it is substantially free of organic nitrogen compounds, it exerts no measurable adverse effect on the conversion catalyst. The rich adsorbent, on the other hand, is treated to desorb the organic nitrogen compound therefrom and to return the adsorbent to a lean state for re-use. In accordance with the invention, such desorption treatment comprises contactingthe rich adsorbent with the conversion product. The use of this substantially nitrogenand sulfur-free conversion product as a stripping or displacement exchange fluid can also be combined for more effective desorption with elevated temperatures and/or reduced pressure in the known manner.

Although the deactivation of the adsorbent is gradual, some deactivation can eventually occur. It is within the scope of this invention toreactivate the silicate adsorbent by occasional high temperature contacting with a hot reactivating gas such as flue'gas, air, etc.

- In the catalytic conversion step, the denitrogenated low velocity can be varied between about 0.1 and about 10, but preferably is maintained at about 2.0. A recycle gas containing hydrogen is maintained flowing through the catalytic reforming zone in a quantity ranging from about 500 s.c.f./b. (standard cubic feet per barrel) to about 10,000 s.c.f./b., but preferably is between about 1,000 s.c.f./b. and 5,000 s.c.f./b. 'Ihe reformer operating pressure can be between about 5 p.s.i.g. and about 500 p.s.i.-g., with a preferred pressure between about 250 p.s.i.g. and about 350 p.s.i.g. Suitable reforming temperatures are between about 800 F. and about 1,050 F.

As previously stated, the hot high octane effluent from the conversion step is contacted with the rich adsorbent in the desorption stage of the adsorption step, thus desorbing the adsorbed organic nitrogen compounds from the adsorbent to produce a lean adsorbent ready for re-use in the adsorption stage and a desorption or stripping etiluent which is cooled and partially condensed. When the conversion operation is one of reforming, the uncondensed gas, rich in hydrogen produced in the reforming step, is recirculated to the reforming step. Under the preferred operating conditions of the catalytic reforming step, the liquid condensate from the desorption efiluent condensation comprises a reformed gasoline substantially free of sulfur which has an anti-knock rating in the order of 100+ (LP-1+3 ml. TEL). I

In accordance 'with a preferred embodiment of the invention, a sulfurand nitrogen-containing gasoline boiling range feedstock is contacted in the presence of hydrogen with a desulfurization-denitrogenation catalyst whereby substantially all of the organic sulfur compounds and V the great majority of the organic nitrogen compounds are octane gasoline effluent from the adsorption step is reheated to hydrocarbon conversion conditions and is contacted in the vaporphase with a conversion catalyst; In most instances, the conversion operation is of the type known as catalytic reforming employing as the catalyst molybdenum trioxide, chromium oxide, cobalt molybdate, the noble metals and the like, individually or in admixture with each other. The dehydrogenation reactionsthat take place in the presence of reforming catalysts convert naphtheue hydrocarbons into aromatic hydrocarbons.

An excellent catlayst for this conversion is one containing between'about 0.01 percent and about 10 percent by weight of platinum and preferably betweenabout 0.1 and 0.5-percent by weight of platinum. The catalyst is usually promoted by the inclusion of aminor amount of halide such as chloride or fluoride or both in the alumina carrier. It is also conventional to add alkyl halides'to the feed to maintain the'catalyst activity. With the reforming catalysts mentioned, the processing conditions can vary over relatively wide ranges. The liquid hourly space decomposed. The products of these reactions are hydrogenated fragments of the sulfur or nitrogen compounds together with ammonia and hydrogen sulfide. Although any desulfurization catalyst is operable in such a catalytic desulfurization-denitrogenation step, it is preferred to employ a cobalt molybdate catalyst supported on a silicastabilized activated alumina carrier. The typical cobalt molybdate catalyst of this type contain between about 7 percentand about 22 percent by weight of total of cobalt oxide and molybdenum trioxide. The molecular ratio of cobalt oxide to molybdenum trioxide is in the range of about 0.2 to about 5.0 mols per mol. One preferred form of cobalt molybdate catalyst analyzes about 3 percent by weight cobalt oxide and about 9 percent by weight molybdenum trioxide with a molecular ratio of about 0.64. Appropriate temperatures for effecting the desulfurization and denitrogenation are between about 575 F. and about 900 F., with the preferred operating temperatures between about 700 F. and about 850 F. The operating pressure can be varied widely between about 50 p.s.i.g.

and about 5,000 p.s.i.g; and is preferably between about 300 p.s.i.g. and about 1,000 p.s.i.g. This pressure is usually substantially the same or slightly higher than the operating pressure used in the catalytic reforming step. The liquid hourly space velocity, measured in liquid volumes of feed per volume of desulfurization catalyst per hour, can be varied between about 0.1 and about 10, but preferably is in the range of from about 1.5 to about 6.5. A hydrogen recycle gas analyzing between about 35 percent and about percent by volume of hydrogen is normally recirculated through the catalytic desulfurization zone at a rate between about 50 s.c.f./b. and 10,000 s.c.f./b. of feed. Preferred hydrogen rates are between aboutL-OOO s;c.f./b. and about 5,000's.c.f./b. Some hy drogen is consumed in the desulfurization and denitrogenation reactions and this reaction hydrogen is conventionally replenished by a portion of the hydrogen produced in the subsequent reforming step. Using the preferred operating'conditions indicated above, a low grade gasoline containing about 0.6 percent by weight of sulfur and about 0.3 percent by weight of nitrogen can be treated to produce an efilu'ent gasoline having a substantially zero sulfur analysis and containing to 300 parts per million of nitrogen. The resulting substantially sulfur-free gasoline is then condensed, the liquid condensate separated from the gas phase, and the condensate re-vaporized to an appropriate temperature for introduction to the subsequent adsorption step. The separated gas phase is then treated to remove accumulated contaminants, e.g., hydrogen sulfide and ammonia, leaving a clean hydrogen-rich recycle gas which is returned to the desulfurization step.

The process of the invention in its preferred embodiment is described in connection with the drawing which accompanies and forms a part of this specification and which takes the form of a schematic flowsheet illustrating the principles of the invention, but which is not to be construed as limiting the invention.

Referring now to the drawing, the essential apparatus includes catalytic desulfurizer 18, first and second adsorbers 38 and 56 and catalytic reformer 50. The feed stream comprises a low grade gasoline having the following characteristics:

TABLE I Feed Analysis:

Sulfur, weight percent 1.2 Nitrogen, p.p.m 260 Boiling range, F. 120-450 Gravity, API 47 Knock rating:

F-l clear 64 F-1+3 ml. TEL 71 The feed naphtha enters the process via line at a rate of 10,000 barrels per day controlled by valve 12 and thence passes to feed heater 14. A hydrogen-containing recycle gas enters line 10 via recycle manifold 72 at a rate of about 1,800 s.c.f./b. of feed, combining with the feed prior to introduction into feed heater 14. Within the feed heater, the feed is vaporized at a pressure of about 450 p.s.i.g. The combined naphtha vapor and recycle gas mixture, at a temperature of about 750 F., passes from the feed heater to catalytic desulfurizer 18 via line 16. Catalytic desulfurizer 18 contains a fixed bed of granular cobalt molybdate catalyst which contains about 3 percent cobalt oxide and about 9 percent molybdenum trioxide on a silica-stabilized alumina carrier. The naphtha vapor is contacted with the desulfurization catalyst bed at a liquid hourly space velocity of about 5, and is almost completely desulfurized and is denitrogenated to a substantial extent. The products of the reaction effected in catalytic desulfurizer 18 are hydrocarbons, hydrogen sulfide, ammonia, and hydrogenated hydrocarbon fragments. The efiluent from catalytic desulfurizer 18 passes through line 20 into condenser 22 wherein the effluent is cooled to a temperature suflicient to condense the gasoline range materials present.

The non-condensed recycle and other gases separated from the condensate in condenser 22 are removed via line 74. These gases are purified in treater 76 to raise the hydrogen concentration by removal of ammonia and hydrogen sulfide through line 78. The hydrogen-rich recycle gas from treater 76 is returned to recycle manifold 72 via line 80. Table II gives an analysis of the liquid product from catalytic desulfurizer 18 which is the condensate stream from separator 26.

The condensate is removed from separator 26 via line 28 to vaporizer 30 wherein the liquid condensate is revaporized. The efiiuent from vaporizer 30, at a tem- 6 perature of about 500 F., then flows through line 32, four-way control valve 34, and line 36 into first adsorber 38.

Adsorber 38 contains a fixed granular bed of a crystalline zeolitic sodium alumino silicate adsorbent (Molecular Sieves 13X) having adsorbed thereon a high octane catalytically reformed gasoline employed as a displacement exchange fluid in a previous operational cycle. As the vaporized feed stream passes through said bed at a liquid hourly space velocity of about 7, substantially all of the residual organic nitrogen compounds present in said stream are adsorbed and the displacement exchange fluid is displaced. The non-adsorbed or raffinate stream which is withdrawn from adsorber 38 through line 40 thus contains some displaced catalytically reformed gasoline as well as the non-adsorbed components of the feed stream, i.e., hydrocarbon components such as naphthenes, paraffins and aromatics. The raflinate stream passes through four-way control valve 42 and line 44 to reformer preheater 46 wherein the feed to catalytic reformer 50 is raised to a temperature of about 910 F. The feed to reformer 50 has substantially the same gravity, knock rating, sulfur content and boiling range as shown in Table II, but has a nitrogen content less than 0.5 p.p.m.

Catalytic reformer 50 contains a fixed bed of a platinum reforming catalyst comprising about 0.3 percent by weight of platinum. The hot feed from preheater 46 enters catalytic reformer 50 via line 48 and undergoes a series of dehydroaromatization reactions at an average reaction temperature of about 910 F. as it is passed over the catalyst bed. The liquid hourly space velocity in reformer 50 is maintained at about 2.0 and a recycle stream containing about 75 percent hydrogen enters via line 73 and flows continuously at a rate of about 3,000 standard cubic feet of hydrogen per barrel of feed through catalytic reformer 50 in admixture with the low octane feed naphtha. The reformer pressure is maintained at about 300 p.s.i.g. The hot effiuent from catalytic reformer 50 is passed via line 52, control valve 42 and line 54 to second adsorber 56 wherein said catalytic reformer effiuent is used as the displacement exchange fluid.

Simultaneously with the foregoing adsorption step being conducted in first adsorber 38, the adsorbent in second adsorber 56 is thus treated with the above-mentioned displacement exchange fluid, i.e., catalytic reformed high octane gasoline from reformer 50. The catalytically reformed gasoline passes upwardly through the adsorbent bed and displaces therefrom the nitrogen compounds which were adsorbed during the previous operational cycle leaving catalytically reformed gasoline components adsorbed on the bed. The efiluent from adsorber 56 constitutes the extract stream, and comprises a mixture of organic nitrogen compounds and catalytically reformed gasoline. It is passed via line 58, four-way control valve 34, line 60, product cooler 62, and line 64 into separator 66. Light recycle gas, used in both the desulfurization and the reforming reactions, is separated from the liquid gasoline product of the process at this point. The separated recycle gas stream from separator 66 is recycled to catalytic desulfurizer 18 via line 71, recycle manifold 72, line 10, feed heater 14 and line 16 as previously described and to reformer 50 via line 73. Said liquid gasoline product from gas-liquid separator 66 is removed to product storage via line 68 at a rate controlled by valve 70. It has the following characteristics:

TABLE III Liquid Reformate Product Such operation places first adsorber 38 into the deso'rption part of the cycle and simultaneously places second adsorber 56 into the adsorption part of the cycle. In the next succeeding cycle the valves are again reversed.-

When the same feed is used and identical operating conditions are maintained in the previously described process except that the adsorption step is bypassed, i.e., when the catalytic desulfurization zone liquid efiluent, as described in Table II, is passed from separator 23 directly to reformer preheater 46, thus bypassing adsorbers 33 and 56, the resulting liquid reformate product from toformer St) is of a much lower quality than shown in Table III. Table IV gives the characteristics of the resultingp'roduct when the adsorption step is omitted, i.e., when the i p,'p.m. of organic nitrogen compounds are not removed from the reformer feed.

TABLE IV Sulfur, weight percent 0.0005 Nitrogen, p.p.m. 4.0 Boiling range, F. 120-425 Gravity, API "in 44 Knock rating (I -1+3 ml. TEL) 92 The removal of a relatively minor amount of organic nitrogen compounds from the reformer feed thus effects a significant improvement in the quality of the liquid reformer product of the process, raising the octane level about nine points while the subsequent transfer of these adsorbed nitrogen compounds to the final process product had no deleterious effect on the high product quality.

Although the process of thisinvention has been described above in detail by reference to a particular catalytic desulfurization-denitrogenation step, an intermediate adsorptive denitrogenation step, and a subsequent catalytic dehydroaromatization step, the present invention is applicable to the treatment of any nitrogen-containing feedstock destined for catalytic conversion and refining processes which are adversely aifected by the presence of organic nitrogen compounds. For example, the catalytic reforming step described above can be substituted with a catalytic isomerization step, a catalytic cracking step, or other catalytic conversion step. Usually, the feedstock will have been pretreated for the removal of the organic compounds of sulfur and any desulfurization process can be employed for this purpose. In each of these refining processes the quantity and quality of the eifiuent from the catalytic conversion zone is markedly improved by removing from the conversion zone feed all of these nitrogen and sulfur contaminants. 7 Thus, the process of this invention shows a wide variety of advantages over the prior art since it 1) upgrades low octane. gasoline feeds to a high level with a greater liquid yield, (2) allows less severe desulfurization conditions to be used to yield the same level of desulfurization and prolong the desulfurization catalyst life, (3) permits the use of less'severe reforming conditions for the same octane increase, (4) protects the reforming catalyst from the rapid deterioration found with organic" nitrogen contaminants, (5) and simultaneously" effects" the convenient "and ekpeditious disposal: in the product 's'oline of the residual organic nitrogen compounds'rfnoyed from the reiornier feed.

Other media-canons and adaptations which would occur to one skilled inthis particular art are to be included in the spirit and scope of this invention as defined by the following claims.

I claim:

1. A process for upgrading a hydrocarbon feed mixture boiling in the gasoline boiling range and containing normally incident organic nitrogen compounds, said process icluding a. hydrocarbon conversion step carried out in the presence of a catalyst which is adversely affected by the presence of said organic nitrogen compounds, comprising (1) contacting said feed mixture with a solid granular adsorbent consisting essentially of a partially dehydrated zeolitic metallo alumino silicate adsorbent having pores. of substantially uniform diameter between about 7 A. and about 13 A., whereby there is obtained a raflinate essentially free of organic nitrogen compounds and a rich adsorbent containing adsorbed organic nitrogen compounds; (2) contacting said rafiinate with said catalyst under hydrocarbon conversionconditions to obtain a conversion eifiuent; and (3) directly contacting said rich adsorbent with said conversion effluent, whereby there is obtained a single process product comprising said conversion product and "desorbed organic nitrogen compounds.

2. A process according to claim l wherein the said adsorbent comprises a calcium sodium alumino silicate having substantially uniform diameter pores of about 10 A.

3. A process according to claim 1 wherein the said adsorbentcomprises a sodium alumino silicate having substantially uniform diameter pores of about 13 A.

4. A process according to claim 1 wherein said conversion catalyst is adehydroaromatization catalyst.

5. A process according to claim 1 wherein Steps (1) and (3) are effected in the vapor phase.

6. The process for upgrading a hydrocarbon feedmixture boiling in the gasoline boiling range and contaminated with normally incident organic sulfur compounds and normally incident organic nitrogencompounds, said process comprising a. hydrocarbon conversion step carned out in the presence of a catalyst which is adversely aife'cted by the presence or" said contaminants, comprising: (1) contacting said feed mixture with a desulfurizatron catalyst at desulfurizing conditions whereby there is obtained a first eliluent comprising gasoline boiling range hydrocarbons substantially free of organic sulfur compounds and containing reduced amounts of said organic n trogen compounds; (2) contacting said first efl luent with a solid granular adsorbent consisting essentially of a partially dehydrated zeolitic metallo alumino silicate having pores of a substantially uniform diameter between about 7 A. and about 13 A., whereby there is obtained a second hydrocarbon efiluent substantially free of organic nitrogen compounds and a rich adsorbent containing adsorbed organic nitrogen compounds; (3) contacting said second effluent with said conversion catalyst at conversion conditions whereby there is obtained a third efiiuent comprising gasoline boiling range hydrocarbons; (4) directly contacting said rich adsorbent with said third efliuent whereby there is obtained an extract efiiuent of a single process product comprising said third efiluent and desorbed organic nitrogen compounds.

7. A process according to claim 6 wherein the said adsorbent comprises a calciu'mfsodium alumino silicate hailing substantially uniform diameter pores of about 8. A process according to claim 6 wherein the said adsorbent ere. sqd li iflai mino silicate. having substantially uniform diameter pores of about '13 A.

9. Aprocess according to claim, 6 wherein said conversion catalyst is a dehydroaromatization catalyst' 10. A process according to claim 6 wherein said desulfnrization catalyst comprises cobalt molybdate supi ported on an alumina carrier and contains betweenabout 7 percent and about 22 percent by weight total cobalt V oxide and molybdenum trioxide in a molecular ratio of cobalt oxide to molybdate trioxide of between about 0.2 and about 5.0 mols per mol.

11. A process for upgrading a hydrocarbon feed mixture boiling in the gasoline boiling range and contaminated with normally incident organic sulfur compounds and normally incident organic nitrogen compounds which comprises: (1) contacting said hydrocarbon feed mixture in admixture with a hydrogen-containing gas with a desulfurization catalyst at desulfurizing conditions whereby there is obtained a first efiluent comprising non-condensable gases and gasoline boiling range hydrocarbons substantially free of said organic sulfur compounds and containing reduced amounts of said organic nitrogen compounds; (2) separating said non-condensable gases from said gasoline boiling range hydrocarbons; (3) contacting said gasoline boiling range hydrocarbons with a solid granular adsorbent consisting essentially of a partially dehydrated zeolitic metallo alumino silicate having pores of a substantially uniform diameter between about 7 A. and about 13 A. whereby there is obtained a second hydrocarbon effluent substantially free of organic nitrogen compounds and a rich adsorbent containing adsorbed organic nitrogen compounds; (4) contacting said second efiiuent in admixture with a hydrogen-rich recycle gas with a conversion catalyst at conversion conditions whereby there is obtained a third efiiuent comprising hydrogenrich recycle gas and gasoline boiling range hydrocarbons; (5) directly contacting said rich adsorbent with said third effiuent whereby there is obtained an extract eflluent comprising said third efliuent and desorbed organic nitrogen compounds; (6) separating said hydrogen-rich recycle gas from said extract efiluent whereby there is obtained a single high octane gasoline product; and (7) recirculating a portion of said hydrogen-rich recycle gas to Step (1) and a portion of said gas to Step (4).

12. A process for upgrading a hydrocarbon feed mixture whose components boil between about 100 F. and about 500 F and which is contaminated with normally incident organic sulfur compounds and normally incident organic nitrogen compounds which comprises: (1) contacting said hydrocarbon mixture in admixture with a hydrogen-containing gas with a desulfurization catalyst comprising cobalt molybdate at a temperature between about 575 F. and about 900 F., and a pressure between about 50 p.s.i.g. and about 5,000 p.s.i.g., with a liquid hourly space velocity between about 0.1 and about 10.0 liquid volumes of said mixture per volume of said catalyst per hour and with a hydrogen recycle rate between about 50 s.c.f./b. and 10,000 s.c.f./b. of said hydrocarbon mixture whereby there is obtained a first efiluent comprising non-condensable gases and gasoline boiling range hydrocarbons substantially free of said organic sulfur compounds and containing reduced amounts of said organic nitrogen compounds; (2) separating said non-condensable gases from said gasoline boiling range hydrocarbons; (3) contacting said gasoline boiling range hydrocarbons with a solid granular adsorbent consisting essentially of a partially dehydrated zeolitic metallo alumino silicate having pores of substantially uniform diameter between about 7 A. and about 13 A. at a temperature between about F. and about 800 F., and a pressure between about 0 p.s.i.g. and about 1,000 p.s.i.g., whereby there is obtained a second hydrocarbon effiuent substantially free of organic nitrogen compounds and a rich adsorbent containing adsorbed organic nitrogen compounds; (4) contacting said second eflluent in admixture with a hydrogenrich recycle gas with a dehydroaromatization catalyst at a temperature between about 800 F. and about 1,050" F., and a pressure between about and about 500 p.s.i.g.

with a liquid hourly space velocity between about 0.1 and about 10 liquid volumes of said second eiiiuent per volume of said dehydroaromatizatio-n catalyst per hour, and with a hydrogen recycle rate between about 50 sci/b. and 10,000 s.c.f./b. of said second efliuent whereby there is obtained a third efliuent comprising hydrogenrich recycle gas and gasoline boiling range hydrocarbons having a substantially higher octane number than said hydrocarbon feed mixture; (5) directly contacting said rich adsorbent with said third efiluent at a temperature between about F. and about 800 F., and at pressures between about 0 p.s.i.g. and about 1,000 p.s.i.g. whereby there is obtained an extract effluent comprising said third efiiuent and said adsorbed organic nitrogen compounds; (6) separating the hydrogen-rich recycle gas from the extract efiluent whereby there is obtained a single high octane gasoline product; and (7) recirculating a portion of said hydrogen-rich recycle gas to Step 1) and a portion of said gas to Step (4).

.13. A process according to claim 12 wherein the said adsorbent comprises a calcium sodium alumino silicate having substantially uniform diameter pores of about 10 A.

14. A process according to claim 12 wherein the said adsorbent comprises a sodium alumino silicate having substantially uni-form diameter pores of about 13 A.

15. A process according to claim 12 wherein said desulfurization catalyst comprises cobalt molybdate supported on an alumina carrier and contains between about 7 percent and about 22 percent by weight total cobalt oxide and molybdenum trioxide in a molecular ratio of cobalt oxide to molybdate trioxide of between about 0.2 and about 5.0 mols per mol.

16. A process according to claim 12 wherein said dehydroaromatization catalyst comprises between about 0.01 percent and about 10.0 percent by weight of a noble metal promoted by a halide.

17. A process according to claim 12 in combination with the steps of cooling and partially condensing said first effluent; separating the non-condensable gases from the condensate; vaporizing said condensate and introducing it to said Step (3); subjecting said non-condensable gases to treatment for removal of hydrogen sulfide, ammonia and light hydrocarbon gases whereby there is obtained at hydrogen-rich non-condensable gas; and returning said hydrogen-rich non-condensable gas to said Step 1).

18. A process according to claim 12 wherein Steps (3) and (5) are effected in the vapor phase.

19. A process as defined by claim 12 wherein the said adsorbent is periodically contacted with a hot reactivating gas.

References Cited in the file of this patent UNITED STATES PATENTS 1,557,257 La Riboisiere Oct. 13, 1925 2,021,088 Pevere Nov. 12, 1935 2,324,118 Sweeney July 13, 1943 2,653,862 Trimble et al Sept. 29, 1953 2,717,230 Murray et al. Sept. 6, 1955 2,859,170 Dickens et al. Nov. 4, 1958 2,859,173 Hess et al. Nov. 4, 1958 2,886,509 Christensen et a1 May 12, 1959 2,909,574 Woodle Oct. 20, 1959 2,925,375 Fleck et al Feb. 16, 1960 2,937,215 Bleich May 17, 1960 OTHER REFERENCES Article by Barrer, Journal of the Society of the Chemi-v cal Industry, volume 64, May 1945 (pages -13 5

Claims (1)

1. A PROCESS FOR UPGRADING A HYDROCARBON FEED MIXTURE BOILING IN THE GASOLINE BOILING RANGE AND CONTAINING NORMALLY INCIDENT ORGANIC NITROGEN COMPOUNDS, SAID PROCESS INCLUDING A HYDROCARBON CONVERSION STEP CARRIED OUT IN THE PRESENCE OF A CATALYST WHICH IS ADVERSELY AFFECTED BY THE PRESENCE OF SAID ORGANIC NITROGEN COMPOUNDS, COMPRISING (1) CONTACTING SAID FEED MIXTURE WITH A SOLID GRANULAR ADSORBENT CONSISTING ESSENTIALLY OF A PARTIALLY DEHYDRATED ZEOLITIC METALLO ALUMINO SILICATE ADSORBENT HAVING PORES OF SUBSTANTIALLY UNIFORM DIAMETER BETWEEN ABOUT 7 A. AND ABOUT 13 A., WHEREBY THERE IS OBTAINED A RAFFINATE ESSENTIALLY FREE OF ORGANIC NITROGEN COMPOUNDS AND A RICH ADSORBENT CONTAINING ADSORBED ORGANIC NITROGEN COMPOUNDS; (2) CONTACTING SAID RAFFINATE WITH SAID CATALYST UNDER HYDROCARBON CONVERSION CONDITIONS TO OBTAIN A CONVERSION EFFUENT; AND (3) DIRECTLY CONTACTING SAID RICH ADSORBENT WITH SAID CONVERSION EFFUENT, WHEREBY THERE IS OBTAINED A SINGLE PROCESS PRODUCT COMPRISING SAID CONVERSION PRODUCT AND DESORBED ORGANIC NITROGEN COMPOUNDS.

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