US2875150A - Heavy oil conversion with low coke formation - Google Patents

Description

' Feb. 24, 1959 s. c. scHUMAN HEAVY OIL CONVERSION WITH LOW COKE FORMATION Filed Nov. 12. 1953 g sa]J JL-T-.Z

JE j INVENTOR.

`smv/@UR Lc. scHuMAN BY i AGENT United States Patenti@ rice N HEAVY OIL CONVERSION WITH LOW COKE FORMATION Seymour C. Schuman, Titusville, N. J., assignor to Hydrocarbon Research, Inc., New York, N. Y., a corporation of New Jersey Application November 12, 1953, Serial No. 391,582

10 Claims. (Cl. 208-107) This invention relates to the conversion of heavy oils into more valuable products, more particularly, the invention is directed to the conversion of hydrocarbon oils boiling above about 700 F. and containing a substantial proportion of asphaltenes. o

A principal object of this invention is to convert vheavy hydrocarbon oils into valuable gaseous and liquid products with low coke formation. Further objects and advantages will be apparent from the description which follows.

In accordance with the invention, heavy hydrocarbon oil is injected into a high-velocity gaseous stream containing hydrogen and carrying in suspension a heated particulate carrier whereby the oil is converted into volatilized products and a carbonaceous deposit on the carrier. The heavy oils for which the process is particularly adapted may derive from petroleum, coal, tar sands and oil shale and are characterized as boiling essentially above about 700 F. and having a Ramsbottom carbon value (ASTM No. `D`52452T) of at least about 10 and very frequently above 15. Such oils are generally highly aromatic and contain a large proportion of asphaltenes and resinous compounds. To convert heavy oils to lighter liquid and gaseous products with low carbon formation, it has been found necessary to subject the oil in the presence of hydrogen to a temperature in therange of about 1200. to 1600 F., preferably 1300 to 1500 F., for a period not exceeding about 3 seconds, preferably not exceeding about 1 second. C

The process employs a finely divided solid carrier, generally of a size that all passes through a Ll-mesh sieve and preferably at least about 50% by weight thereof passes through a G-mesh sieve. The carrier, heated to provide temperatures in the aforesaid conversion range when contacted by the heavy oil, is carried in suspension by a hydrogen-containing gasiform stream traveling at a Velocity of at least 10, preferably at least 20, feet per second. Under these conditions, the carrier 'particles travel with substantially the same velocity of the suspending gasiform stream. Although the carrier particles may in some instances experience a little slippage relative to the gasiform stream, the velocity of the particles will still be at least 70% of that of the gasiform stream.

It is a noteworthy feature of this invention that the conversion of heavy hydrocarbons to more valuable products is carried out at low hydrogen partial pressure and yet the formation of carbon is materially curtailed. Hydrogen partial pressures as low as about 35 p. s. i. (pounds per square inch) 'are effective in the process of this invention. The hydrogen partial pressure is preferably in the range of 75` to`200 p. s. i. and generally does not exceed 400 p. s. i. The process consumes considerable hydrogen in the conversion of heavy oils; for instance, a consumption of approximately 1000 standard cubic feet of hydrogen per barrel of charge heavy oil is frequently encountered.

i The short-time, high-temperature conversion of heavy oils is carried out with the carrier particles dispersed as 2,875,150 Patented Feb. 24, 1959 a dilute phase in the suspending, high-velocity gasiform stream. Generally, the carrier loading does not exceed about 5 pounds per cubic foot of suspending gas and often is in the range of about 1 to 2 pounds per cubic foot.

In the course of the hydrocarbon conversion, carbonaceous material is deposited on the carrier particles. The thus fouled carrier, after stripping absorbed heavy hydrocarbons therefrom, is subjected to regeneration. Advantageously, the fouled carrier is reacted with oxygen and steam at temperatures of at least about 1600 F., preferably in the range of 1700 to 2000 F. to yield regeneration product gases containing a substantial proportion of hydrogen. The regenerating gas contains a preponderance of steam and a minor proportion of highpurity oxygen, the latter usually containing atleast about 90% by volume of oxygen and preferably atleast 95% by volume of oxygen. Steam-to-oxygen volume ratios in the range of 1.5:1 to 5:1 are generally satisfactory for generating the required hydrogen. In many instances, the steam-to-oxygen volume ratio is of the order of 2:1 to 3:1.

The particulate carrier employed in the process of this invention is any solid material that will withstand the desired regeneration conditions, including a temperature above 1600 F., Without physically disintegrating or fusing, such as sand, quartz, alumina, magnesia, Zircon, beryl or bauxite. Absorptive carriers of the type disclosed in the copending application of C. A. Johnson and S. C. Schuman, Serial No. 388,903, filed October 28, 1953, are preferred.

To describe and explain this invention more fully, reference is made to the accompanying drawings where- 1n:

Figure 1 diagrammatically illustrates an apparatus adapted for carrying out the process of the invention; and

Figure Zis a diagrammatic vertical section of a hydrocracker incorporating therein the process of this invention.

Referring now to Figure 1, finely divided. carrier, all passing through an -mesh sieve, heated to a temperature of about 1750 F. in regenerator 10 is passed through slide valve 12 into conversion conduit 14 where it is suspendedin a high-velocity gaseous stream containing hydrogen, which is introduced into conduit 14 lat the point 16. Into the stream carrying the heated carrier particles through conduit 14 at a velocity of about 25 feet per second, a heavy residuurn is injected through feed line 18 and valved branch line 20. Alternatively, the feed stock may be injected into conduit 14 through valved branch line Z2 or valved branch line 24 depending upon whether a somewhat shorter or a somewhat longer conversion time is desired. The mixture of feed stock and carrier dispersed in the gaseous stream has a temperature in the range of 1300 to` 1500 F. The stream discharges from conduit 14 into cyclone separator 26 where the carrier particles now coated with carbonaceous matter are separated from the gasiform stream containing the cracked hydrocarbons. The fouled carrier particles pass down from cyclone Z6 through Vstandpipe 28 into regenerator 10, while the gasiform efluent is withdrawn through outlet 30 and sent to a conventional recovery system which separates the products of conversion into desired fractions.

Steam and `oxygen are introduced into the lower pory tion of regenerator 10 `by way of distributor 3. A small quantity of steam is injected through tap 34 into the.

ofgabout"175.0 `to yeldsaregeneration product 'gas rich in hydrogen. While the :oxygen is substantially completely reacted in the lower portion of regenerator 10, it is preferred to have a baille structure 38 disposed at an intermediate'level in 'the ,iluidized mass of carrier within regenerator so as to curtail top-to-bottom mixing. The upper portion of the yiluidized bed which has a pseudo-liquid level 36 provides va Zone in which the fouled catalyst discharging from standpipe 28 is subjected to stripping to remove absorbed hydrocarbons from the fouled catalyst. While the regeneration product gases are very effective for stripping absorbed hydrocarbons from the fouled carrier, additional gas, such assteam, may be introduced through distributor 40 `particularly where it is desired to maintain a lower temperature in the portion of the fluidized mass above baffle structure 38. Thus, thefouled carrier may besubjected to stripping ata ternperature `of about 1500 F..above baille structure 33 and regenerated at a temperature of about l750 F. below battle structure 38. The regeneration product gases along with stripped hydrocarbons on emerging from the pseudoliquid level 36 are withdrawn from regenerator 10 through outlet 42 and passed to a conventional recovery system to separate out the hydrocarbons from the normally `gaseous components of that stream.

The suspending gas introduced into conduit 14 at the point .16 may be derived fromthe gaseous. stream leaving regenerator 10 at outlet 42. It is also possible to recycle hydrogen-containinggas which isseparated from the gasiforrn .etiluent withdrawn at outlet 30.

The apparatusof Figure 2 is essentially a hydrocracker as disclosed inthe copending application of J. A. Finneran,` Jr., and F. B. Grosselfnger, Serial No. 299,114, -led July 16, 1952, but modified to include the high-temperature, short-time cracking of a heavy recycle stock in accordance with this invention. Vessel 50 contains a tluidized carrier mass with a pseudo-liquid level 52. The upper portion of the uidized mass provides a primary cracking zone S4, .an intermediate portion containing packing bodies 56 like Raschig rings provides a secondary cracking zone 58 and the lower portion provides a regeneration zone .60. The packing bodies `56 are supported on .a perforated plate 62. Thecharge stock is supplied to zone S4 through distributor 64 while oxygen and steam for regeneration of the carrier particles are introduced through distributor 66. The temperature of primary crackingzone54 is generally maintained in the range of 85.0 .to 1100 F., preferably in the range .of 900 to 1050 F., While regeneration zonef is maintained at a ternperature of atleast 1.600'.F., preferably in the range of 1700 to 2000 F. Fouled carrier from zone 54 moves down through packed zone 58 countercurrent to regeneration product gases rich -in hydrogen and thus is subjected to stripping conditions at increasing temperatures as the carrier approaches zone 60. The carrier stripped of absorbed hydrocarbons discharges from zone 58 into zone 60 where the carbonaceous residue on the carrier particles is gasied by reaction with oxygen and steam.

Regenerated carrier flows from .zone 60 through opening 68 into .up-transport conduit 70. The flow of carrier through opening .68 may be yregulated by the position of valve body '7,2 mounted on tube 74 which is moved vertically by turning threaded handle 76. The carrier is conveyed up through .conduit'70into zone 54 by a suspending gas ,introduced through ,tube 74.

The total reaction eiiluent comprising the cracked hydrocarbons rand the hydrogenfcontaining regeneration product gases emerges from pseudo-liquid level 52, passes through cyclone separator 78 and Vflows through outlet 80 .to .a conventionalrecoyery plant .to fractionate the liquid and gaseous products.

'Pursuant to .this invention, .theheaviest hydrocarbon fraction, boiling above 700 F., .obtained from the total reaction e'luent is recycledforurther conversion. This recycle stock is .injected through line 82 and nozzle 84 into Yc`oriduit'70 whereit is dispersed in a'hi'gh-velocty gaseous stream containing hydrcgenand.conveyingregenerated carrier particles. The gas supplied through tube 74 contains suicient hydrogen to provide in conduit 70 a hydrogen partial pressure in the range of 35 to 400 p. s. i. This hydrogen-containing gas may be obtained by the fractionation of the totalgasiform effluent leaving vessel 50 through outlet 80. The recycle stock is thus further converted at temperatures in the range of 1200 to 1600 F. for a period of about l to 3 seconds. The con versionproducts from the recycle stock discharge into the uidized ,carrier mass in zone 54 where a substantially lower temperature is maintained; hence, the deep cracking eected in conduit 70 is arrested by the .quenchingaction of the tluidized carrier vin zone 54. The amount of recycle stock which is .converted in .conduit 70 may be varied considerably. It is possible and even commercially attractive to charge a heavy oil to primary cracking zone 54 through distributor 64 and to withdraw fromlthe re covery plantas end products only gasoline and vlighter" EXAMPLE l An apparatus as illustrated in Figure 1 is charged with bauxite averaging 160-mesh particle size. At an operatv ing gauge pressure of 400 p. s. i., the unit treats5, 000 barrels per day of an asphalt fraction obtained by the propane deasphalting of a 25% by weight Kuwait residuum and having the following characteristics:

Specific gravity Ramsbottom carbon residue,` wt. percent 27 Sulfur, wt; percent 6 The charge stock, preheated to about 550 F., is .injected into hydrogen-containing gas flowing through conduit 14 at a rate of about 38 MM s. c. f. d. (million standard cubic feet per day). At the point of oil injection, the combined stream has a temperature of about 1450" F. and this temperature decreases to about 1300 F. when the streamreaches cyclone separator v26. The oil lis at conversion conditions for approximately .1 sec. ond. The combined gas and oil stream has an average velocity of about-25 feet per second, a hydrogen partial pressure of about p. s. i. and a bauxite loading of about 1.5 pounds per cubic foot ,of gas.

About 3.4 MM s. c. f. d. of oxygen (96% by volume purity) and 6.8 MM s. c. f. d. of steam respectively preheated to 300 F. and 1000 F. enter through conduit 32 to regenerate fouled bauxite at a temperature of about 1850 F. An additiona1'0.6 MM. s. c. f. l.d of steam is supplied through tap 34. Wet steam is .introduced through distributor 40 to maintain the .,uidizedmass above baille structure 38 at a temperature of about 1500 F.

The gasiform eluent from outlet 30 vis -processedin a recovery yplant to separate out gasoline and lfuel oil .of the quality and in the quantity shown in the first column of Table I. The .gaseous residue of the euent yis scrubbed with a suitable solvent, e. g., diethanolarnine,

lto eliminate substantially all of the hydrogen sulde .and

carbon dioxide therein, and then .contacted -in the pres ence of added steam vwithan iron-chromium -waterggas shiftcatalyst at a temperature of about 775 F. to ytransform its carbon monoxide content to carbon dioxide hydrogen. After removal of water -vaporand carbon n f" dioxide nem th'esiiifted of theremainder.,` `This gasisrecycled to conduit 14 atthe rate of 38 MM s. c. f. dias aforesaid',while an ad-- ditional 19 MM s. c. i. d; is withdrawn from the system as an end product, namely,; a` fuel gas of high heating value. ip ,h i

` EXAMPLEEgZL--.

the regenerator in lieu of `steam and oxygen andsteam gas, Aresulting hydrogen-` i enriched gas ycontains about 75% by volume of hy drogen, and gaseous hydrocarbons whichY make up most In a run similar to thatof Example l, axrdlsused 1n Vals?":intuir ln` a run similar to that of Example 3, none of the heavy end fraction is recycled to conduit 70 and steam' is used in lieu of hydrogen-containing gas as the transport gas in conduit 70. The conversion products are given in the fourth column of Table I. It is noteworthy that the gasoline yield `and quality are inferior to those of Example 3 and the product gas is lower in heatin value and quantity.

Table I Example.-. c 1 2 `a 4 Design .s 'Figi Figi i Flg.2 Flg.2

i p Transport Gas Steam Hi-Conf i Steam taining `gaizliierating Gas Air 02+H1i0 01+Hi0 e 2 Gasoline. Barrels per Day 1,370 990 14,240 12,950, FueliOll. Barrels per Day. 945 685 830 i 4,140 i. FuelGas, MM s. c. 1.1L.. 19.0 59.3 95.5 78.9

` 'Gasoline Quality:

`Octane Number, CFRR Clear- 09.2 98.9 90.2 88.0 i i i Sulfur, Wt. percent 0.31 1.70 0.41 V 0.45

" Fuel Oil Quality:

G 1.12 1.20 1.22 l'. p 4.7 12.4 8.a s f aso aaa soo '44o servesas the transport-gas in'conduit 14. The quality` L It is evident from the examples that the"process df and VLquantity ofthe conversion" products are l shown in the second column ofTable I.V lIt shouldebe noted that no-only is the yield of'liquid "precincts1 lower than; in Example l but also the sulfur contents.` M A An apparatus" ais/Lil uitrated in Figure 2 1s charged with liquid products have much higher thensalmesize bauxite used in Examplefl. Operating i The charge stock is admixed with 23,000 barrels per day of recycled middle distillate obtained from the `gasiform eluent leaving vessel 50 through outlet 80. The admixed oils, preheated to a temperature of 550 F., are charged through distributor 64. About 21.9 MM s. c. f. d of oxygen (96% by volume purity) and 43.8 MM s. c. f. d. of steam respectively preheated to about 300 F. and 1000 F. are used to regenerate fouled carrier at a temperature of about 1850 F. A heavy end fraction recovered from the gasiform eflluent exiting at outlet 80 is recycled through line 82 and nozzle 84 at the rate of 8300 barrels per day. Hydrogen-containing gas derived from the gasiform eiluent leaving vessel 50 through outlet 80 is passed through conduit 70 at the rate of 84 MM s. c. f. d. and with a velocity of Vapproximately 30 feet per second. The recycled oil is exposed in conduit 70 to a maximum temperature of about 1400 F., a hydrogen partial pressure of 120 p. s. i., a bauxite loading of approximately 2 pounds per cubic foot of gas and a residence time of nearly 1 second. The temperature in the primary cracking zone 54 is 980 F.

The effluent leaving through outlet 80 is fractionated into gasoline, the aforesaid middle distillate (boiling range of 400 to 700 F.) the aforesaid heavy end fraction (boiling above 700 F.) and a gaseous residue. All of the middle distillate is recycled to distributor 64. The heavy end fraction is split into the 8300 barrels per day charged to line 82 and an additional 830 barrels per day which are withdrawn from the system as fuel 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, onlyv such limitations should be imposed as are indicated by the appended claims.

What is claimed is:

1. A process for the conversion of a heavy hydrocarbon oil having a Ramsbottom carbon value: of at least about l0, which comprises injecting said oil into a rapidly moving gaseous stream containing hydrogen and having a velocity of at least about 10 feet per second and conveying dispersed heated carrier particles from. a regeneration zone hereinafter specified in substantially the same direction as that of said gaseous stream to yield a mixture having a hydrogen partial pressure of at least about 35 p. s. i. and a temperature in the range of about 1200 to 1600 F., maintaining said mixture at temperatures in said range for not more than about 3 seconds, separating said carrier particles from said mixture, recovering converted hydrocarbons from the remaining gaseous portion of said mixture, treating the separated carrier particles in the aforesaid regeneration zone with oxygen and steam at a temperature above about 1600 F. to reheat said separated carrier particles and to gasify carbonaceous material deposited thereon by said oil thereby producing hydrogen-containing gases, recovering from said gases said gaseous stream containing hydrogen, and again conveying the reheated carrier particles from the aforesaid regeneration zone in said gaseous stream containing hydrogen as aforesaid.

2. A process for converting heavy hydrocarbons boiling, above about 700 F. and having a Ramsbottom car dief For stocks of high sulfur while the hydrocarbons are of the invention is con-V ducted at elevated pressure ,to i maintain .the contemplated hydrogenr partial pressure. Inmost instances,ioperation at a gauge pressurein therange of `1501011000 p. s. i. i is satisfactory; the preferredrange is 250 4to ;65O1p."s. i: Y

bonvalue ofaat least about 10 to lighthydrocarbons boil,- ing bel'ow' about'.4.00"` F., .which comprises conveying .heated carrier particles 'rom'a regeneration zone heretemperatures in said range for not more than about 3 seconds, separating said carrier particlesv from said mixture, recovering'said lighthydrocarbonsfrom the-remaining gaseous portion of said mixture, treating the sep.- arated'carrier particles in the aforesaid regenerationV zone with oxygen andsteamat a temperature above about I of"`about 1'200 to 1600 F., maintaining said mixture at 16009" F. to rehe'at'r said'separatedfcarrier particles' and-V toygasify earbonaceous` material. deposited thereon vby. said oil thereby producing hydrogen-containing gases, recover.. ing; from said gases said gaseous streamcontaining hydrogen, andy again conveyingl the reheated carrier particvlesj from the, aforesaid regeneration zone inA saidlgaseous stream containing hydrogen as aforesaid.

3. The process of claim 1 wherein each. cubic, foot. of."

said gaseous stream containingv hydrogen conveysv not more than about 5 pounds of said heated carrier. particles.

4. The process of claim. Lwhereinsaidcarrier particles arebauxite particles. f

5. The process of claim 2 wherein. eachcubic footofvv said gaseous stream. containing. hydrogen conveys not morethanabout 5..pounds, of said heated carrier particles. 6. Thefprocess ofg clain1 2wherein said'mixture `has a hydrogen partial pressure of at least about 75 p. s..i.

7'.: A; processfor converting heavy ,hydrocarbons boil-1. ing above about 700 F. and having a'Ramsbottom car-J1 bon .value oflat least about. 10 to light hydrocarbons boiling;.b'e1ow. about 400 F.,r which comprises conveyingheated'. carrier particlesfrom a regeneration zone herevinafter specified-by suspension in a gaseous stream-conp taining hydrogen and having a velocity of at least about Ztleetrlltfr second so that said carrier particles travelin substantially the, samerdirecti'on as lthatnof said' gast-OBS... stream, injectingsaid heavy'hyd'rfocarbons'into thesus-T pension o flsad carrier; particlesfin Said gaseous .streamto form ar mixturefhavingga hydrogenpartial pressurein..

the range of about v to. 200 p..s. i. and a .temperature in the rangeofaboutl'Orto 1F00".`V F.maintaining saidi Y mixturek at temperatures in said range fornot more than about 1 second, separating said carrier particles from said mixture, recoveringfsaidlight@ hydrocarbons from the remaining gaseousr portion off said mixture,wreheat ing the separated.. carrier praticles in the aforesaid. re-v generation zone by reactingthe carbonaceous material deposited on said carrier particles by said heavy hydrocarbons with oxygen and steam at a temperature in the .range-of. about 1700 to 2000 F. thereby producing hydrogen-containingv gases, recovering from said gases said gaseous stream containing hydrogen, and again convey- 'ing thefreheated carrier particles from the aforesaid regeneration: zone in said gaseous stream containing hydrogen; as aforesaid.

8.The process of claim 7 wherein the reaction of the carbonaceous material with oxygen and steam is conducted` by passing said oxygen and steam upwardly through a` mass of said carrier particles with said carbonaceousmaterial deposited thereon under fluidizing conditions.

9. The' process of claim 7 wherein each cubic foot of said. gaseous stream containing hydrogen conveys not more. than-abouti; poundsfof. saidheated carrier: particles.,v

1:0...Tl1e process.. cfilamf/ wherein.said` heavy hydro5v carbons. have. ai. Ramsbottom. carbon,- value of .at least; y.

about. 1.5;y an d,. a sulfugf.- content-of' at 4least about 5%. by-I weight.Y y v y y p y l v References Cited in Gle of this patent.A UNITED SATES. PATENTS 2.411.104 Genti 255.7;680. u .Qdell June 19.195,1 12.60.63.862Y Keith .-Augzl 12, 1952;-- 2,687,992 Leffer ...,Augv4 31,` 1954 My 24. rafts,

Beckberger Mai-..13, 1956 .l

Claims (1)

1. A PROCESS FOR THE CONVERSION OF A HEAVY HYDROCARBON OIL HAVING A RAMSBOTTOM CARBON VALUE OF AT LEAST ABOUT 10, WHICH COMPRISES INJECTING SAID OIL INTO A RAPIDLY MOVING GASEOUS STREAM CONTAINING HYDROGEN AND HAVING A VELOCITY OF AT LEAST ABOUT 10 FEET PER SECOND AND CONVEYING DISPERSED HEATED CARRIER PARTICLES FROM A REGENERATION ZONE HEREINAFTER SPECIFIED IN SUBSTANTIALLY THE SAME DIRECTION AS THAT OF SAID GASEOUS STREAM TO YIELD A MIXTURE HAVING A HYDROGEN PARTIAL PRESSURE OF AT LEAST ABOUT 35 P. S. I. AND A TEMPERATURE IN THE RANGE OF ABOUT 1200 TO 1600*F., MAINTAINING SAID MIXTURE AT TEMPERATURES IN SAID RANGE FOR NOT MORE THAN ABOUT 3 SECONDS, SEPARATING SAID CARRIER PARTICLES FROM SAID MIXTURE, RECOVERING CONVERTED HYDROCARBONS FROM THE REMAINING GASEOUS PORTION OF SAID MIXTURE, TREATING THE SEPARATED CARRIER PARTICLES IN THE AFORESAID REGENERATION ZONE WITH OXYGEN AND STREAM AT A TEMPERATURE ABOVE ABOUT 1600*F. TO REHEAT SAID SEPARATED CARRIER PARTICLES AND TO GASIFY CARBONACEOUS MATERIAL DEPOSITED THEREON BY SAID OIL THEREBY PRODUCING HYDROGEN-CONTAINING GASES, RECOVERING FROM SAID GASES SAID GASEOUS STREAM CONTAINING HYDROGEN, AND AGAIN CONVEYING THE REHEATED CARRIER PARTICLES FROM THE AFORESAID REGENERATION ZONE IN SAID GASEOUS STREAM CONTAINING HYDROGEN AS AFORESAID.

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