US2906696A - Reforming of naphtha with unpromoted activated carbon and regeneration of the catalyst - Google Patents

Description

4Unite y 'REFORlVIING 0F NAPHTHA WITH UNPROMOTED ACTIVATED CARBON AND REGENERATION OF THE CATALYST Application July 8, 1953, Serial No. 366,691

6 Claims. (Cl. 208-134) This invention relates to the production of high octane gasolines from hydrocarbon oils, and is more particularly concerned with a process for the production of such gasolines from virgin naphthas and `gas oils.

Arithmetic averages in January 1952, for motor gasoline sold in 45 U.S. cities, indicate research octane ratings of 83.2 and 90.0 for regular and premium gasolines, respectively, with such gasolines containing an average of 1.35 and 1.75 cc./ gal., respectively, of tetraethyl lead. Since present trends in high compression ratio automotive engines indicate that even higher anti-knock ratings will be required in the future, recent research and developement has been concentrated on improving the octane number of refined gasolines. Thus, whereas formerly, it had been the practice to convert part or all of the higher boiling fractions of the crude oil to materials boiling in the gasoline range by a thermal cracking process, this practice has been supplanted by the commercial use of the process commonly referred to as catalytic cracking, because of the ability of the catalytic process to produce gasoline of the presently desired octane rating. Similarly, it has been customary petroleum refining practice to employ a thermal noncatalytic process to reform virgin naphtha to gasoline of higher octane number; however, recently developed processes have applied catalytic principles to the reforming of such naphtha, to produce a reformed gasoline of considerably higher octane number than that which can be produced by thermal reforming. However, none of these catalytic reforming processes has been wholly satisfactory from a practical standpoint. Thus, a process commonly referred to a hydroforming was developed about thirteen years ago and was utilized to produce aviation gasoline during World War II. However, since 1945, although the requirement for a catalytic reforming process to produce high octane motor gasoline has been great, hydroforming has not been extensively used for this purpose because of economic disadvantages resulting from high capital and operating costs. Similarly, a process known as platforming has been recently developed for reforming virgin naphtha to high octane gasoline. factory owing to the high cost of the platinum catalyst used in its operation and owing to the fact that heavy naphthas with end points boiling above 400 F. are processed only with difficulty, if at all. Similarly, numerous other processes for reforming naphtha have been proposed, but have notV found general commercial acceptance because of high catalyst cost and various economic and operating disadvantages.

It is an object of the present invention to provide an improved process for producing high octane gasoline from hydrocarbon oils.

Another object is to provide an improved process for producing high octane gasoline of commercially acceptable characteristicsv from low octane virgin naphthas of a boiling range which may extend signicantly into the gas oil fraction (above 400 R).

This process, however, is not entirely satis- States Patent Still another object of the invention is to provide a process of the character indicated which is effective in producing a high yield of high octane gasoline from hydrocarbon oils.

A further object is to produce high octane gasoline from heavy hydrocarbon oils with a catalyst that is readily maintained at high activity without the necessity of periodic or continuous addition of fresh quantities of an expensive catalyst.

These and additional objects and advantages of the invention will be apparent from the description which follows.

In accordance with the invention, the hydrocarbon oil to be processed is brought into contact at an elevated temperature with a catalyst comprising carbon of high surface area in a conversion zone, the catalyst being initially produced and continuously regenerated by high temperature treatment with oxygen and steam in a regeneration zone, with the gaseous products of the regeneration reaction, comprising hydrogen, carbon monoxide, and carbon dioxide, as well as excess steam, being advantageously utilized as part or all of the gaseous environment in the conversion Zone. A high octane gasoline fraction is recovered from the hydrocarbon reaction products in high yields `and from the gasiform effluent which accompanies the hydrocarbon reaction products, propane and propylene `are removed by conventional yabsorption procedures. Part of the unabsorbed gas is advantageously fed to the regeneration zone to supply the heat requirements of the process.

As will be apparent as the description proceeds, the invention provides an eflicient process for the production of high octane, high quality gasoline from hydrocarbon oils. It is a feature of the invention that the yields of gasoline of :a given octane number are comparable with those provided by other catalytic processes, although the latter require catalysts of high initial and replacement cost, whereas in the present invention the catalyst is provided at relatively small cost.

It is another feature of the invention that heavy naphtha charge stocks with end points in the kerosene and gas oil boiling ranges can be processed to provide high quality gasoline in yields comparable to those obtained from lighter naphtha charge stocks.

It is another feature of the invention that hydrocarbon conversion is carried out eiciently tand economically in a continuously operating system, in which the required heat of reaction is supplied by means which make possible the attainment of the isothermal conditions under which the highest yields of high octane gasoline are obtainable. The hydrogen produced in the catalyst regeneration step is, as previously mentioned, advantageously used to provide the gaseous environment for the reactions in the conversion zone to improve product yields, and the carbon monoxide which is also produced in the regeneration step is a valuable raw material which may be recovered for use, for example, in the manufacture of methanol or in the synthesis of further quantities of gasoline by the hydrocol process.

The catalyst employed in accordance with the invention and brought into contact with the oil to be treated in the conversion zone is predominantly carbon which has a high surface area characteristic of the materials generally designated as activated carbons. It has been found that such activated carbon canv be made from a variety ofv organic substances such as coal, petroleum residues, wood, coconut shells, lignite, sugar and the like. However, activated carbon obtained by conventional commercial procedures is expensive and has not been used successfully for catalytic reactions in which a nonvolatile carbonaceous deposit is `formed on the surface of the carbon catalyst, since such a deposit markedly reduces catalyst activity. In the present invention, the deleterious effect of the non-volatile carbonaceous deposit (henceforth referred to as coke to differentiate from the high surface area carbon catalyst) is avoided by continuous regeneration under conditions which preferentially consume the coke rather than the underlying active carbon. The small amount of active carbon which may be consumed is easily and continuously replaced by the addition of an inexpensive carbonizable organic material, preferably coal or petroleum coke, which is conveniently added as such directly to the reaction system and therein automatically activated under the herein specified conditions which prevail in the system. Thus, the carbon catalyst in the conversion zone can be maintained at all times in the desired active state. It has been found that by maintaining the surface area of the catalyst not less than about 400 square meters per gram (as conventionally measured by low temperature nitrogen adsorption, using the method of Brunauer, Emmett and Teller, I. Am. Chem. Soc. 60, 309, 1938), its catalytic activity is suitable for effecting the desired degree of reforming. However, to secure optimum results, the equilibrium surface area of the catalyst should be maintained in the range of about 500 to 900 square meters per gram.

The hydrocarbon oil, preheated to about 600 to 900 F., is introduced into the conversion zone, maintained at a temperature in the range of about 900 to 1075 F., preferably in the range of 925 to 1050 F., and containing the carbon catalyst of high surface area supplied from the regeneration zone. In the conversion zone, the total pressure is maintained in the range of 5 to 600 p.s.i.g. (pounds per square inch gage), the particular value depending upon the presence or absence of the regeneration product gases in the conversion zone. When these gases are not passed into the conversion zone, the total pressure is at the lower end of the above-specified range, preferably 5 to 100 p.s.i.g., but when the regeneration product gases are used to provide the gaseous environment for the conversion reactions, then the higher pressures are employed, preferably 250 to 600 p.s.i.g. In any case, the partial pressure of the hydrocarbon oil is maintained between l0 and 100 p.s.i.g. (pounds per square inch), preferably in the range of 15 to 60 p.s.i. Advantageously, the desired reaction is effected with a hydrocarbon oil feed rate in the range of 0.5 to 5, preferably 0.5 to 1.5 volumes of liquid per hour per volume of catalyst in the conversion zone.

A carbonaceous deposit or coke is formed on the catalyst surfaces during the hydrocarbon conversion. In accordance with the invention, the thus-fouled catalyst is passed to a regeneration zone for removal of the coke. Before entry into the regeneration zone, the catalyst is stripped of adsorbed hydrocarbons with steam or the gaseous products of regeneration. The catalyst is then heated to the desired regeneration temperature. For this purpose, oxygen and steam may be brought into contact directly with the catalyst, consuming some of the catalyst to produce the desired heat. This method is made possible only because the catalyst consumed can be inexpensively replaced by a make-up supply of inexpensive coal or petroleum coke which is rapidly activated under the regeneration conditions hereinafter specified.

Alternatively, if desired, the catalyst may be heated to regeneration temperatures by bringing it into contact with oxygen (either air or high-purity oxygen) and recycle gas from the gasiform effluent of the conversion zone. In this case. the required heat is obtained predominantly by combustion of the recycle gas. However, a small portion of the catalyst may be consumed, necessitating some make-up of the catalyst with coal or petroleum coke as described above. In accordance with another alternative procedure, the oxygen and recycle gas are burned in tubes which are immersed in and surrounded by the catalyst so that the catalyst is heated without coming into contact with oxygen, thus reducing catalyst consumption and make-up requirements to a minimum.

In the regeneration zone, the catalyst heated by any of the above described means to a temperature of 1600 to 2200 F., preferably 1700 to 2000 F., is brought into contact with an excess of steam to complete regeneration to the desired surface area. It has been found that with a dense fluidized bed at superficial gas velocities of 0.2 to 1.0 foot per second and with residence times of l to 30 minutes in the regeneration zone, the carbonaceous deposit containing some hydrogen is selectively removed from the carbon catalyst because of its greater reactivity under the conditions employed. The coke on the catalyst can be removed without significant consumption of the catalyst base, and the latter, regenerated to its initial high surface area, is then fed back to the conversion zone. In addition, under the regenerative conditions employed, such amounts of solids which are added as catalyst make-up are also activated at a rate sufficient to maintain the above-specified equilibrium surface area in the carbon catalyst.

While it is not desired to be bound by any particular theory of operation, it appears that the reaction:

2CH+2H2O 3H2+ 2CO (l) is more rapid at a given temperature than the reaction: C-i-HZOeCO-l-Hz (2) In addition, Reaction 1 is endothermic with the result that after some reaction has occurred on a particle it becomes cooled, decreasing the chance of any significant consumption of catalyst by Reaction 2. Regeneration in a fluidized bed having a net directional motion is considerably more successful than regeneration in an externally-heated fixed bed wherein a broad temperature gradient exists from the heat transfer wall to the center of the bed with the result that carbon is preferentially consumed at the wall.

The product gases from the regeneration zone contain not only hydrogen and carbon monoxide but also excess steam utilized in the regeneration zone. In the preferred embodiment of the invention, these product gases are passed into the conversion zone and serve as the atmosphere for the hydrocarbon conversion. Under these conditions wherein a total pressure of 250 to 600 p.s.i.g. is preferably employed, a desirable hydrogen partial pressure of 35 to 200 p.s.i., preferably 75 to 150 p.s.i., is readily obtained in the conversion zone. It has been found that in such case the coke produced from the hydrocarbon oil feed is less than when the aforesaid gaseous environment is absent. In addition, the rate of deactivation of the catalyst is significantly lowered as a result of this hydrogen-rich gaseous environment.

The process of the invention is not limited to a particular form of apparatus and it may be effectively carried out in any convenient apparatus. Advantageously, however, the carbon catalyst is utilized in a particle size range suitable for fluidization, i.e., smaller than 20 mesh, and the process is carried out in a fluidized bed. The conversion and regeneration zones may be in fluid-communicating, separate vessels but are advantageously provided in a single vessel. In the latter case, the products of regeneration containing hydrogen as well as carbon monoxide, carbon dioxide and steam pass over the catalyst in the conversion zone where they mix with the hydrocarbon products of conversion before leaving the reaction vessel. When the process is carried out in a single vessel adapted for fiuidized operation, the flow of fluidized catalyst from the conversion zone to the regeneration zone is advantageously restricted by flow-impeding materials or devices of the type generally designated as packing or trays which permit the maintenance of a large temperature differential between these two zones.

When the process is first started up, activated carbon of the type commercially marketed may be employed as the initial catalyst charge to the reactor. However, an organic solid such as coal or petroleum coke is preferably employed as the initial charge to the reactor and is activated within the reactor itself. Since many solids of the type suitable for activated carbon formation contain some ash, provision may be made for withdrawal of some solid from the reactor. However, because it is possible to reach the desired catalyst activity with carbon containing up to 35% by weight of ash, and because solids suitable for activation containing less than 5% by weight of ash, such as petroleum coke, and certain anthracites, can be employed, such wtihdrawalr of solid can be maintained at economically low levels. The use of coal to supply the initial and make-up requirements of the catalyst represents an important feature of the invention, since the cost of such catalytic raw material is substantially less than the platinum, molybdenum and chromium-containing catalysts which have been employed in prior processes for reforming hydrocarbon oils.

The gasiform euent from the reactor contains a mixture of light gaseous hydrocarbons boiling below the gasoline range, gasoline of 400 F. end point, a small vamount of higher boiling hydrocarbons (gas oil), and in the preferred embodiment of the invention wherein the regeneration product gases provide the gaseous atmosphere in the conversion Zone, hydrogen, carbon Inonoxide. carbon dioxide and steam. These products are separated and recovered by conventional methods. The gasoline may be stabilized and brought to the desired vapor pressure by conventional procedures before marketing. The portion of the efuent boiling belowthe gasoline range issubjected to oil scrubbing or similar procedures that will effect a high degree of removal of valuable quantities of propylene and propane which are produced in the process. A portion of the residual gases from the scrubber may be recycled back into the reactor to supply process heat by combustion with oxygen in the regeneration zone. The remainder is product gas and contains a large quantity of hydrogen and carbon monoxide, both of which may be employed in other chemical manufacturing or rening operations.

The gasoline recovered from the process meets all commercial requirements and specifications with respect to colorV and storage stability. Furthermore, this gasoline may be produced with extremely high anti-knock ratings. For example, it has been found that it is possible to prepare a gasoline of 100 CFRR clear octane rating by the process of this invention. However, it is more economical to produce a gasoline of 90 CFRR clear octane rating, which with the addition of 3 mL/gal. (milliliter per gallon) of tetraethyl lead has a 99.5 CFRR octane rating.

For a fuller description of the invention, reference is made to the accompanying drawings wherein are schematically shown reaction vessels adapted for carrying out the process of the invention:

Figure 1 is a sectional elevation of a single reaction vessel containing both the conversion zone and the regeneration zone; and

Figure 2 is a similar view of another embodiment wherein the two zones are in communicating vessels, showing also the relationship of the product recovery `System-Y` The reactor illustrated in Fig. 1 comprises a cylindrical vessel having opposed ends 12 and 14. In the llowerfportion of vessel 410 is disposed a concentric tubular shell 16, backed up with a refractory insulating material such as firebrick, to protect the metal walls of vessel 10 from the high temperatures which are reached in regeneration zone 18. Above regeneration zone 18 is section 20 which is filled with packing, for example, 2-inch ceramic Raschig rings, to prevent excessive top-tobottom'mixing of the catalyst in this section and thus to make it possible to maintain different temperatures in regeneration zone 18 and conversion zone 22. The packing is supported on perforated plate 23. When the reactor is in operation, it is filled with fluidized catalyst to pseudoliquid level 24 in conversion zone 22. 'I'he catalyst is maintained in continuous circulation throughout vessel 10, moving downwardly from conversion zone 22 through section 20 into regeneration zone 18 and then returning, after regeneration, to conversion zone 22. For the return of the regenerated catalyst there is provided an axial tip-transport tube 26 extending upwardly from the lower end 14 of vessel 10 into conversion zone 22. Passage of regenerated catalyst into up-transport tube 26 is controlled by a valve arrangement comprising inlet aperture 30 and vertically adjustable valve body 32 mounted on tube 34 which is exteriorly movable. Movement of the catalyst upwardly through transport tube 26 is effected by supplying a stream of iluidizing gas, which may be recycle gas or steam, through tube 34.

In the embodiment illustrated in Fig. 1, the process heat in regeneration zone 18 is supplied by burning recycle gas with oxygen or a mixture of oxygen and steam in burner 36. Preheated recycle gas is fed to burner 36 through conduit 38 and oxygen or a mixture of oxygen and steam is supplied through conduit 40. Regeneration steam enters zone 18 through conduit 42 and distributor 44. Similarly, the preheated, vaporized hydrocarbon oil feed enters zone 22 through conduit 46 and distributor 48. The Vhydrocarbon conversion products, together with hydrogen, carbon monoxide, carbon dioxide and steam are removed from vessel 10 through outlet 50, a cyclone 51 .being advantageously provided to remove at leastrsome of the catalyst which may be entrained by the eluent gases.

If it is desired to replace catalyst consumed in the reactor, make-up solids may be fed into the top of conversion zone 22 from a pressurized hopper (not shown) n through conduit 52. Similarly, solids may be removed through conduit 54. The exterior of vessel 10 is provided with insulation (not shown) to prevent undue heat loss.

In Fig. 2, hydrocarbon oil and recycle gas are fed to reactor through conduits 138 and 114, respectively, and stripping steam through conduit 112. Similarly, air, with or without steam, and recycle gas are fed through conduits and 117, respectively, to burner 121 and thence the combustion products flow to regenerator 111. Steam for catalyst activation enters regenerator 111 through conduit 113 and the gaseous products of regeneration leave vessel 111 through line 119. Make-up 4coal or like solid may be added to regenerator 111 through line 136 and high ash solid withdrawn through line 123.

The hydrocarbon conversion products from reactor 110 pass through conduit 116 into fractionator 118 from the bottom of which gas oil boiling above 400 F. is Withdrawn. Gasoline boiling below 400 F. leaves fractionator 118 through line 122, and light gas through line 120, the latter passing into separator 126 wherein C., and C5 hydrocarbons are removed. These C., and C5 hydrocarbons are combined with the gasoline removed by line 122 to form the gasoline product which is withdrawn from the system through line 128. Propane and propylene are removed in depropanizer 130', leaving through line 129. Part or all of the uncondensed gases containing hydrogen and gaseous hydrocarbons is vented through conduit 132. The remainder is recompressed by means of booster and then supplied to reactor 110 and burner 121 through lines 114 and 117, respectively. Part or all of the regenerator eflluent may likewise be supplied to reactor 110 and burner 121, as described, by way of line 119. The arrows in vessels 110 and 111 and the connecting conduits show the direction of flow of the carbon catalyst.

The following examples will serve to illustrate the invention more specically without, however, being intended as limitative thereof:

Example I In carrying out the process of the invention in the apparatus of Fig. 1, the apparatus is started up with a charge of Ieddo anthracite coal passing through a 20 mesh screen. Oxygen and steam, preheated to 300 F. and 800 F., respectively, are introduced through conduit 42, and the solids are circulated until a temperature of 1800 F. is reached in zone 18. The amount of oxygen fed through conduit 42 is then reduced to the level required to maintain the temperature of 1800 F. in zone 18. In about 12 hours, the solids develop a surface area of about 800 square meters per gram. During this time, fresh coal is continuously fed to the reactor to maintain the desired bed level, thereby replacing coal which is consumed to provide process heat.

After the desired catalyst activity has been obtained by the above-described starting-up procedure, heavy naphtha is fed through conduit 46 and distributor 48 into zone 22 at the rate of 5000 barrels per day. This naphtha is derived from East Texas crude and has the following characteristics:

Shortly after the naphtha feed is initiated, oxygen feed through conduit 42 is discontinued while a flow of 52 M s.c.f.h. (thousand standard cubic feet per hour) of steam continues through conduit 42 into zone 18. About 100 M s.c.f.h. of recycle gas containing on a volume basis approximately 48% hydrogen, 15% methane, 9% ethylene and ethane, 7% carbon monoxide and 21% carbon dioxide, are then introduced to burner 36 through inlet 38 and 66 M s.c.f.h. of oxygen and 99 MM s.c.f.h. of steam are fed through inlet 40. The recycle gas has been preheated to 300 F. and the steam and oxygen to 800 F. and 300 F., respectively. Solids residence time in zone 18 is 10 minutes.

After the apparatus has been thus put on stream, the solid circulation rate is regulated to 36,000 lbs. per hour by adjustment of valve 32. The total pressure is 400 p.s.i.g. with hydrogen and naphtha partial pressures in zone 22 of 100 p.s.i. and 87 p.s.i., respectively. The temperature of zone 22 is 975 F. and that of zone 18 is 1800 F. with a gradient between these temperatures existing in section 20 which is packed with 2-inch Raschig rings. The dimensions of zone 22 correspond to a space velocity of 1.0 volume of liquid naphtha per hour per volume of catalyst.

In steady operation, about 500 lbs. per hour of catalyst is consumed in excess of the coke (1130 lbs. per hour) produced by the hydrocarbon conversion. The addition of 1150 lbs. per hour of fresh coal through conduit 52 is adequate to maintain the desired solids content in the reactor and to maintain the ash content of these solids at about 30% by weight with simultaneous withdrawal of solids from the uidized bed through conduit 54 at a rate of 80 lbs. per hour.

The reactor effluent is separated into 4170 barrels per day of reformed naphtha of 400% F. end point, 80 barrels per day of gas oil boiling above 400 F., and 10.3 MM s.c.f.d. (million standard cubic feet per day) of a normally gaseous fraction containing the light hydrocarbon products of conversion together with hydrogen, carbon monoxide and carbon dioxide, nearly one-fourth of this gaseous fraction being recycled to burner 36. The product gas contains 48% by volume of hydrogen and is ultimately converted to about 71 tons per day of ammonia, employing 1.9 MM s.c.f.d. of nitrogen obtained from the air fractionation plant that provides oxygen to burner 36. "i il The octane number of 10# RVP (Reid vapor pressure) gasoline product is 80.0 CFRM clear, 89.3 CFRR clear and 97.6 CFRR-l-3 cc./gal. tetraethyl lead. This gasoline meets present requirements for premium product without addition of tetraethyl lead or other antiknock additives.

Example 2 In carrying out the process of the invention in the apparatus of Fig. 2, the unit is put on stream and the catalyst activated as in Example l. After the desired catalyst activity level has been attained, 5000 barrels per day of a mixture of heavy naphtha and light gas oil are fed through conduit 138 into the dilute phase feed line, together with 13.3 M s.c.f.h. of recycle gas. The charge stock derived from East Texas crude has the following properties:

Gravity, API 42.6 Distllation, F.:

I.B.P 230 10% 350 30% 394 50% 425 70% 456 492 521 Aniline point, F 140 Bromine number cgs./gm. 7

This stock, containing over 60% by volume of material boiling above 400 F., is markedly heavier than charge stocks which have been used in other catalytic reforming processes. In addition to the petroleum stock and recycle gas, 57.8 M s.c.f.h. of stripping steam is fed into vessel through conduit 112.

Recycle gas preheated to a temperature of 300 F. is supplied to burner 121 through line 117 at the rate of 41.8 M s.c.f.h. Additional activation steam is supplied to regenerator 111 through conduit 113 at the rate of 10.0 M s.c.f.h.

The total pressure in reactor 110 is 20 p.s.i.g., whereas regenerator 111 is at a total pressure of 10 p.s.i.g. The dimensions of reactor 110 correspond to a space velocity of one volume of liquid charge per hour per volume of catalyst. The dimensions of regenerator 111 give an activation time of about 20 minutes with a solid circulation rate of 39,000 lbs. per hour. Fresh coal is added at the rate of 1270 lbs. per hour through conduit 136, and 85 lbs. per hour of solids are withdrawn through conduit 123.

The hydrocarbon conversion products are fractionated in column 118 with 3870 barrels per day of gasoline being removed through line 128. A product boiling above 400 F. is recovered through conduit 124 at the rate of 360 barrels per day, indicating an excellent conversion to gasoline of the heavier fractions of the charge stock. About 375 barrels per day of liquefied petroleum gas is also recovered from depropanizer through line 129. A residual gaseous product leaves the system through conduit 132 at the rate of 130 M s.c.f.h.; this gaseous product is of high caloriiic value averaging 1300 B.t.u. (net) per standard cubic foot. The gasoline product has an antiknock value of 77.5 CFRM clear, 86.8 CFRR clear, and 96.0 CFRR with 3 cc. of tetraethyl lead per gallon.

In general, hydrocarbon distillates with end points up to about 700 F. are advantageously processed in accordance with this invention. Preferably, the charge stocks are naphthas with end points below about 550 F.

In View of the various modifications of the inventlon 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 continuous process for reforming a naphtha distillate with an end point below about 550 F. to yield a gasoline fraction of high antiknock characteristics which comprises passing said distillate in contact with hydrogen and moving particles of unpromoted activated carbon having a surface area of at least about 400 square meters per gram in a conversion zone maintained at a temperature in the range of about 900 to 1075 F. and at a total pressure inthe range of about 250 to 600 pounds per square inch gage, said distillate passing into said conversion zone at a space velocity in the range of 0.5 to volumes of liquid per hour per volume of activated carbon in said conversion zone, transferring from said conversion zone to a regeneration zone particles which have been contaminated with carbonaceous material deposited during the conversion of said distillate, treating the transferred particles while in motion with steam at a temperature of at least about 1600 F. thereby restoring said particles to activated carbon having a surface area of at least about 400 square meters per gram and simultaneously forming hydrogen-containing regeneration product gases, returning restored particles to said conversion zone, utilizing said hydrogen-containing gases to maintain the hydrogen in said conversion zone at a partial pressure of at least 35 pounds per square inch, and removing the products of conversion from said conversion zone.

2. The process of claim 1 wherein the partial pressure of said naphtha distillate in said conversion zone is about to 100 pounds per square inch.

3. A continuous process for reforming a naphtha distillate with an end point below about 550 F. to yield a gasoline fraction of high antiknock characteristics which comprises passing said distillate in contact with hydrogen and moving particles of unpromoted activated carbon having a surface area of at least about 400 square meters per gram in a conversion zone maintained at a temperature in the range of about 900 to 1075 F. and at a total pressure in the range of about 250 to 600 pounds per square inch gage, said distillate passing into said conversion zone at a space velocity in the range of 0.5 to 5 volumes of liquid per hour per volume of activated carbon in said conversion zone, introducing into said conversion zone particles of an organic material selected from the group consisting of coal, petroleum coke, petroleum residues, wood, coconut shells, lignite and sugar, transferring mixed particles from said conversion zone to a regeneration zone, treating said mixed particles while in motion with steam at a temperature in the range of about 1600 to 2200 F. thereby converting said mixed particles to activated carbon having a surface area of at least about 400 square meters per gram and simultaneously forming hydrogencontaining regeneration product gases, returning converted particles to said conversion zone, utilizing said hydrogencontaining gases to maintain the hydrogen in said conversion zone at a partial pressure of at least 35 pounds per square inch, and removing the products of conversion from said conversion zone.

4. The process of said 3 wherein the organic particles are coal particles.

5. A continuous process for reforming a naphtha distillate with an end point below about 550 F. to yield a gasoline fraction of high antiknock characteristics which comprises passing said distillate in contact with hydrogen and fluidized particles of unpromoted activated carbon having surface area of at least about 400 square meters per gram in a conversion zone maintained at a temperature in the range of about 925 to 1050 F. and at a total pressure in the range of about 250 to 600 pounds per square inch gage, said distillate passing into said conversion zone at a space velocity in the range of 0.5 to 5 volumes of liquid per hour per volume of activated carbon in said conversion zone, transferring said particles from said conversion zone to a regeneration zone, reacting the transferred particles in a uidized state with oxygen and steam at a temperature in the range of about 1700 to 2000 F. thereby to maintain in said particles a surface area of at least about 400 square meters per gram and simultaneously to form hydrogen-containing regeneration product gases, returning reacted particles to said conversion zone, utilizing said hydrogen-containing gases to maintain the hydrogen in said conversion zone at a partial pressure of at least pounds per square inch, and removing the products of conversion from said conversion zone.

6. In the process of reforming a naphtha with an end point below about 550 F. to yield gasoline and normally gaseous hydrocarbons at an elevated conversion temperature by contact with hydrogen and particles of unpromoted activated carbon, in a conversion zone the improvement of maintaining the surface area of said particles in contact with said naphtha at a value of at least 400 square meters per gram which comprises heating a. portion of said particles while in motion by combustion of at least part of said gaseous hydrocarbons, the combustion product gases coming into direct contact with the thus heated portion, reacting the thus heated portion while in motion with steam at a temperature in the range of 1600 to 2200 F. thereby increasing the surface area of said portion and simultaneously producing hydrogencontaining gas, returning the portion with increased surface area to contact with said naphtha, and admixing the hydrogen-containing gas with said naphtha to maintain a hydrogen partial pressure of at least 75 pounds per square inch during the conversion of said naphtha, while maintaining a total pressure in the range of about 250 to 600 pounds per square inch gage during said conversion and a space velocity of said naphtha in the range of 0.5 to 5 volumes of liquid per hour per volume of activated carbon in said conversion zone.

References Cited in the tile of this patent UNITED STATES PATENTS 2,284,603 Belchetz May 26, 1942 2,428,715 Marisic Oct. 7, 1947 2,587,425 Adams Feb. 26, 1952 2,592,603 Sanford Apr. 15, 1952 2,606,862 Keith Aug. 12, 1952 2,626,233 Kimberlin et al. Jan. 20, 1953 2,663,676 Cardwell Dec. 22, 1953 2,738,307 Beckberger Mar. 13, 1956 OTHER REFERENCES Advances in Catalysis, vol. III (1951), p. 253, article by Wheeler, Academic Press, Inc., publisher.

Claims (1)

1. A CONTINUOUS PROCESS FOR REFORMING A NAPHTHA DISTILLATE WITH AN END POINT BELOW ABOUT 550*F. TO YIELD A GASOLINE FRACTION OF HIGH ANTIKNOCK CHARACTERISTICS WHICH COMPRISES PASSING SAID DISTILLATE IN CONTACT WITH HYDROGEN AND MOVING PARTICLES OF UNPROMOTED ACTIVATED CARBON HAVING A SURFACE AREA OF AT LEAST ABOUT 400 SQUARE METERS PER GRAM IN A CONVERSION ZONE MAINTAINED AT A TEMPERATURE IN THE RANGE OF ABOUT 900 TO 1075*F. AND AT A TOTAL PRESSURE IN THE RANGE OF ABOUT 250 TO 600 POUNDS PER SQUARE INCH GAGE, SAID DISTILLATE PASSING INTO SAID CONVERSION ZONE AT A SPACE VELOCITYIN THE RANGE OF 0.5 TO 5 VOLUMES OF LIQUID PER HOUR PER VOLUME OF ACTIVATED CARBON IN SAID CONVERSION ZONE, TRANSFERRING FROM SAID CONVERSION ZONE TO A REGENERATION ZONE PARTICLES WHICH HAVE BEEN CONTAMINATED WITH CARBONACEOUS MATERIAL DEPOSITED DURING THE CONVERSION OF SAID DISTILLATE, TREATING THE TRANSFERRED PARTICLES WHILE IN MOTION WITH STEAM AT A TEMPERATURE OF AT LEAST ABOUT 1600*F. THEREBY RESTORING SAID PARTICLES TO ACTIVATED CARBON HAVING A SURFACE AREA OF AT LEAST ABOUT 400 SQUARE METERS PER GRAM AND SIMULTANEOUSLY FORMING HYDROGEN-CONTAINING REGENERATION PRODUCT GASES, RETURNING RESTORED PARTICLES TO SAID CONVERSION ZONE, UTILIZING SAID HYDROGEN-CONTAINING GASES TO MAINTAIN THE HYDROGEN IN SAID CONVERSION ZONE AT A PARTIAL PRESSURE OF AT LEAST 35 POUNDS PER SQUARE INCH, AND REMOVING THE PRODUCTS OF CONVERSION FROM SAID CONVERSION ZONE.

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