US2875147A

US2875147A - Hydrocarbon conversion process

Info

Publication number: US2875147A
Application number: US375133A
Authority: US
Inventors: Theodore M Engle
Original assignee: Hydrocarbon Research Inc
Current assignee: Hydrocarbon Research Inc
Priority date: 1953-08-19
Filing date: 1953-08-19
Publication date: 1959-02-24
Anticipated expiration: 1976-02-24

Description

Feb. 24, 1959 T. M. ENGLE HYDRocARBoN CONVERSION PRocEss Filed Aug. 19, 1953 x OF- 1 3 e 8 SW. W 7 LALML O .7 L 4 FO JNVENTOR. THEoooRE M. EN|GLE BY mf' I 2,875,147 HYDROCARBON CONVERSION PROCESS meedere M.Engle, Pennington, N..J.,assigmrm Hydrocarbon Research,rll1c.,` New York, N. Y., a corporation of New Jersey d d d Appliasion Angustia, 1953,'stria1No. 315,133

' s claims; `(Cl. 20s-59) This" invention relates to the` high-temperature treatment of `hydrocarbons and is more. particularly concelhed' with the efficient production of high octane gasline""from heavyhydrocarbon oils.

`The `invention is"`particularly` applicable to the conversion of heavy charge stocks which cannot be economically treated by conventional processes. It can elticientlyjconvert reduced ,crudes of high Ramsbottom carbon residue into `economic yields of high octane gasline. Itcanalso be used on Vheavy crudes which, on

eating, 'would prlcduc'e a .coke salable only for low Vgrade fuel purposes by"re'a"son of it's sulfur and/o1"` nitro- 'gen and/rmietal content. It can be used on lighter il stocks which contain catalyst poisons such as metals and, therefore, are unsuitable for direct charging to catalytic crackers. 1 d

`Recently proposed proesses suggest .converting hy dr'carboiih oils at elevated pressures and temperatures by contact with `afmass ofheatedcontact material in the. presence of hydrogen.,. One such process, described copending application of Finneran et`al.`,l` Serial` No. 299,114, iilediuly 16, 1952', discloses contactingthefhydrocarbon oil with` a A,flliidized `bed ofparticulate contact material, the `particles ofiwhicl'i circulate between the', conversionzone and a hydrogen-producing regen-` Thus, an object-of `the invention is to provide a dex ible, `high-temperature treating process, by means of which gasoline of high octane number,` high stability and `low sulfur content, is=produced from low grade, heavyhydrocarbon oils. i l l `Other objects and advantages will be .apparent from the' description which follows. A l i i f i `In accordance withthe invention, hydrocarbon "oil is` converted.` Yiii-an elongatedwupow' conversion zone by contact with a `liydrog'en'containing gas and" a particulatef contact material or carrier withdrawn from a tluidized` bett` r The uidized bed 'fis dividedintofat least` two zones, a reaennsrne (hereinafter called the secondary con-` version zone) into whichdthe carrier passes after contacting, the hydrocarbon oil` in the elongated upow or primary `e`onvesin ione, and-a regeneration zone whereinua regeneratinggas` comprising ,predominant-ly steam and oxygen reacts at temperatures above about 16002" United States Patent G ize-the carrier in the secondary conversionione imparts.`

21,875,147 Patented Feib. 24, 1959 ice F. with carbonaceous material deposited `on the carrier by the hydrocarbon conversion toform hydrogen-containing regeneration product gases; the regeneration product gases pass up" through the bed, iluidizing the carrier particles and aiding the hydrocarbon.` conversion in the secondary conversion zone.

Circulation of carrier between the fluidizcd bed` and the upow or primary hydrocarbon conversion zone is largely independent of circulation within the bed between regeneration zone and secondary conversion zone. As one result, the optimum carrier-to-oil ratio (.pounds of carrier per pound of charge oil) for the primary hydro@ carbon conversion may be set without adverse eiect on regeneration conditions, just as regeneration conditions may be set without adverse elect on the primary hydrocarbon conversion. Then again, freeing the primary' conversion zone` -from any dependence upon regeneration conditions imparts additional degrees `of flexibility. For example, at any particular `carrier-to-oil'` ratio in the generally employed Vrange of 1:1 to l5 :1., they zone of primary conversion may vary, e. g., from a dilute gaseous suspension of carrier as low as 0.5 pound per cubic foot, moving, at a linear velocity as high as 40 `feet` per second, to an upowing denser suspension as high as 10 pounds per cubic foot transported by gas having a velocity as `low as 3 feet per second. Generally; the hydrogen content of the suspending gas is atleast 20% by volume. The `hydrogen content and total amount of suspending Agas used in the primary conversion Vzone are also freed from dependenceY on the op,- erating conditions of the regeneration zone. However, the regeneration zone `is thepreferred originalsource foi-the hydrogen. Hydrogen is present in the .gaseous elliuent` `from the secondary Conversion zone as well` as `in thepure regenerationV product gases. A stream of either of `these two gases, after suitable,treatmenttoinj crease the, `hydrogencontent when desired, w-ill serve well for `the suspending gas in thefprimary conversion zone.`

`Generally, the primary conversion zoneroperates in= the temperature range of #about 800 to 1050* F., prei" erably 850` to 950 `F., with a carrier-tooilrratio in the preferredqrangeof 21:1 to ltlrlandl a `carriertogas ratio in the range of about 2` to 6 pounds `per cubic foot of suspending gas at conversion pressure and temperature. Total pressure may range from V150 to 1000` p. s. i. g. (pounds per square inch gage); hydrogenpartial pressure should be atleast 35 1p. s. i. (pounds per` squareinchf)r,the Vrange of 75 to 400 p. s. i. being preferred:` Withinthese ranges,4 operating conditions in the primary conversion` zone `aregenerally` selected to `achieve maxi` mum production of high octane gasoline consistent with,

minimum production of 4coke `from the charge oil. To

this end', `completefconversion `of the' hydrocarbons into the ultimate productsis-lbest not attempted `in `the primary conversion zone.` Rather, an `appreciable portion, of the conversion is performed in the -secondary con-1 maintained at temperatures ranginglfrom -50 tcl-200 Fa above the temperature in the 4primary conversion zoneby directly returning freshly regenerated carrier particles from Ythe regeneration zone to the secondaryconversiom zone. Using the-hot 4regeneration product gasesttuidadditional heat and, more importantly, prtivideswtheiiy-r `carrier to the secondary conversion zone.

drogen-containing atmosphere so beneficial for the completion of the hydrocarbon conversion. The hydrocarbonaceous deposit formed on the carrier particles 1n the primary conversion zone is converted into volatilized products and a non-volatile carbonaceous residue or coke by the time these particlespass from the secondary conversion zone to the regeneration zone. The secondary conversion zone appears to be particularly beneficial, when `operated at a hydrogen partial pressure in the range of 35 to 200 p. s. i., in minimizing the quantity of material that must be removed from the carrier by regeneration.

In the regeneration zone, the coke deposit on the carrier is reacted with regenerating gas consisting essentially of steam and oxygen at a temperature in the range of y1600 Vto 2500 F., preferably 1700 to 2000" F. The regeneration of the carrier results in the production of a gaseous mixture comprising essentially hydrogen, carbon monoxide, carbon dioxide and excess steam. The regenerating gas contains a preponderance of steam and a minor proportion of high-purity oxygen, the latter more specifically containing at least about 90% by volume of oxygen, preferably at least 95 %.by volume of oxygen, and obtained, for example, by the liquefaction and rectilication of air. Steam-to-oxygen molar ratios in the range of 1.5:1 to 5:1 are generally satisfactory for generating the desired hydrogen. It is frequently preferable toemploy a steam-to-oxygenmolar ratio of the order of 2:1 to 3:1.

An up-transport zone serves to return hot regenerated In the luptransport zone which is fed with carrier particles from the regeneration zone, the carrier particles ilow upwardly because of the, lower fluid-static head maintained in this zone. The gas velocity in the up-transportv zone is generally in the range'of about 0.5 to 5 feet per second. The transportgas may be steam or recycled product gas from which, preferably, all hydrocarbons containing more than two carbon atoms have been removed.

The carrier circulation rate is advantageously controlled to ensure that regeneration does not completely consume the coke deposit on the carrier for the reason that regeneration at temperatures above 1600" F. with steam and oxygen activates the carbon left on the carrier. Preferably, the carrier returning through the up-transport zone has about l to 3% by weight of activated carbon. In this fashion, the catalyticproperties residing in activated carbon may be utilized in the hydrocarbon conversion. For example, lowered production of diolens may be attained through the catalytic influence of activated carbon, diolens apparently being readily hydrogenated to more saturated compounds; also, much of the sulfur originally present in the hydrocarbon'oil is catalytically converted to hydrogen sulfide. These catalytic properties of activated carbon are effectively brought to bear on the hydrocarbonY charge stock through the good gas-solids contact achieved by the dilute phase operationl of the upow or primary conversion zone.

The particular 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, berylorbauxite.

To describe and explain this invention more fully, reference is made to the accompanying drawing which shows diagrammatically a vertical section of a reactor adapted for carrying out the process of the invention.

In the operation of the apparatus illustrated, a heavy hydrocarbon oil, preferably preheated to about 600 F., is supplied by line and brought into contact with hot carrier particles leaving conduit 12. Hydrogen-containing suspending gas from line 14 sends carrier and hydrocarbon oil up'through the conduit forming primary conversion zonevl wherein much of the hydrocarbon oil is 4 f converted into volatilized products and a hydrocarbonaceous deposit on the carrier.

Gas, fouled carrier and volatilized products of the conversion pass from primary conversion zone 16 into a cylindrical vessel 18 containing iluidized bed 20 of carrier particles. Bed 20 is Idivided into an upper secondary conversion zone 22 and a lower regeneration zone 24 by a packed section 26 which is provided by a perforated plate 25 supporting a mass of packing bodies 27, e. g., Raschig rings. Carrier particles from zone 22 move downwardly through packed section 26 in contact with regeneration product gases flowing upwardly from zone 24. The fouled carrier particles reaching regeneration zone 24 have only a carbonaceous residue of very low hydrogen content. Primary conversion zone 16 discharges suspending gas, carrier and all conversion products directly into the upper portion of zone 22 of iluidized' bed 20 but may be arranged to `discharge into the gas-solids disengaging space 19 above bed 20. All of the gases and volatilized products from both zone 16 and bed 20 pass through cyclone separator 28 and into line 30. u

Zone 22 of uidized bed 20 together with packed section 26 provides the locus for secondary conversion. In subjacent regeneration zone 24, steam and oxygen supplied by line 32 react with the carbonaceousresidue or coke deposit on the carrier toA yield regeneration product gases consisting essentially of hydrogen, carbon oxides and excess steam which in uidizing bed 20 provide the hydrogen-containing atmosphere for secondary conversion. The regeneration incompletely consumes the coke deposit, leaving activated carbon on the carrier particles.

An upright tube 34 open at its bottom to regeneration zone ,24 and at its top to zone 22 permits the return of regenerated carrier to zone 22 by means of a gasiform transport medium injected intoV the base of tube V34 through the tubular stem 35 of adjustable valve 36. The opening33 in tube 34 may be partially or completely closed by suitable vertical movement of valve 36.

Carrier particles from fluidized bed 20 are passed to primaryconversion zone 16 through conduit 12 which is provided with valve 13 to regulate the rate of ow of carrier to zone 16.

' The total gasiform effluent passes from reactor 18 by way of separator 28 and line 30 to a conventional recovery plant 42 wherein the effluent is separated into nr- While a substantial portion of this product gas is dis-f charged through line 53 for utilization as a fuel or chemical raw material, a portion enters hydrogen concentration plant 54 wherein by known methods the hydrogen content of the gas is increased from say 20% by volume o Example I' A 25 wt. percent reduced Kuwait crude (8.9 API,

5.3 wt. percent sulfur and 20.2 Wt. percent Ramsbottom;

carbon) is preheated toj500 F. and charged at the rate velocity of about feet'per'seconld. The totalpressure is 400 p. s. i. g. and the hydrogen partial pressure is about 260 p. s. i.

Steam and high-purity oxygen (95 vol. percent oxygen) enter regeneration zone 24 through line 32 at the rates of 77,000 and 72,000 pounds per hour, respectively. An additional 25,000 pounds per hour of steam from line 36 transports regenerated carrier up tube 34. The temperature in zone 24 is maintained at 1800D F. and in Zone 22 at about 975 F.

From the gasiform efuent removed through line 30 is recovered 20,000 barrels per day of a middle fraction boiling between 400 and 800 F. which is recycled by way of line 44 to zone 22. Also, part of the product gas (comprising chiefly hydrogen, carbon monoxide, carbon dioxide, methane, ethane and ethylene) passes through line 52 to concentration plant 54 where it is scrubbed to remove carbon dioxide, then reheated and shifted in the presence of added steam over an iron-chromium catalyst at a temperature of about 750 F. The resultant mixture is again scrubbed to eliminate carbon dioxide and leave a gas containing about 70 vol. percent hydrogen, 14 vol. percent methane, 7 vol. percent ethane and 4 vol. percent ethylene. The hydrogen-rich gas is compressed and passed through line 56 and line 14 to serve as the suspending gas in primary conversion zone 16.

The ultimate products recovered comprise 13,000 barrels per day of high octane gasoline (91 CFRR clear), 4600 barrels per day of fuel oil meeting ASTM specifications for No. 6 fuel oil, 1700 barrels per day of propane, and about 79,000,000 standard cubic feet per day of fuel gas with a heating value of about 490 B. t. u. per standard cubic foot. The gasoline contains 0.2 wt. percent sulfur and has an oxidation stability corresponding to an ASTM induction time of 7 hours.

Example Il ucts issuing from primary conversion zone 16 may be passed directly into a gas-solid separator, the gasiform products removed for treatment per se and only the solids passed into secondary conversion zone 22. Such arrangement simplies the hydrocarbon product recovery system but necessitates duplication of recovery equipment to handle separately the gasiform eflluent from secondary conversion zone 22. Accordingly, all variations conforming to the spirit of the invention are to 4be considered within the scope of the appended claims.

What is claimed is:

1. A hydrocarbon conversion process which comprises forming with heated particulate carrier a lluidized bed divided into `a lower regeneration zone and an upper secondary conversion zone, withdrawing carrier from said secondary conversion zone, contacting a heavy hydrocarbon oil of high Ramsbottom carbon residue with the withdrawn carrier and with a suspending gas containing at least 20% by volume of hydrogen and passing the resulting suspension of said oil and carrier in dilute phase upwardly through an elongated primary conversion zone main- 6 tained `at a temperature inthe range of nabout 180Mo 1050" F. and a pressureinthe ragef aboit 15'0 tofi100`0 p. s. i-` g`. whereby said oil is converted'i'nto volatilized products and a hydrocarbonaceous deposit fouling said carrier, passing fouled carrier from said` primary conversion zone into said secondary conversonzone andtherein converting `said hydrocarbonaceous deposit into coke of low hydrogen content by contact with hydrogen-contain# ing regeneration product gases at a temperature about 50 to 200 F. above the temperature of said primary conversion zone, withdrawing said volatilized products for recovery while limiting the contact thereof with said fluidized bed to not more than the upper end portion of said secondary conversion zone, regenerating carrier in said regeneration zone by reacting the coke thereon with steam and oxygen at a temperature in the range of 1600 to 2500 F. to form said regeneration product gases, separating from said regeneration product gases said hydrogen-containing suspending gas, and circulating said .carrier in said fluidized bed between said secondary conversion zone and said regeneration zone.

2. The process of claim 1 wherein the carrier, hydrocarbon oil and hydrogen-containing suspending gas traverse said primary conversion zone as a dilute phase suspension containing about 2 to 6 pounds of carrier per cubic foot of suspending gas.

3. The process of claim 1 wherein the hydrogen in said primary conversion zone exerts a partial pressure in the range of about 75 to 400 p. s. i.

4. A process for the conversion of 'a heavy hydrocarbon oil of high Ramsbottom carbon residue which comprises forming with heated particulate carrier a lluidized bed divided into a lower regeneration zone and an upper secondary conversion zone, withdrawing carrier from said secondary conversion zone, contacting said oi-l with the withdrawn carrier `and with a suspending gas containing at least about 20% by volume of hydrogen and passing the resulting suspension of said oil and carrier in dilute phase upwardly through an elongated primary conversion zone maintained at a temperature in the range of about 850 to 950 F. and a pressure in the range of about 150 to 1000 p. s. i. g. whereby said oil is converted into volatilized products and a. hydrocarbonaceous deposit fouling said carrier, passing fouled carrier from said primary conversion zone into the upper portion of said secondary conversion zone, said upper portion being at a temperature about 50 to 200 F. above the temperature of said primary conversion zone and the lower portion of said secondary conversion zone having a vertical gradient of increasing temperature approaching the temperature of said regeneration zone where said lower portion is contiguous to said regeneration zone, withdrawing said volatilized products for recovery while limiting the contact thereof with said fluidized bed to not more than the upper end portion of said secondary conversion zone, converting said hydrocarbonaceous deposit into coke of low hydrogen content by contact with hydrogen-containing regeneration product gases while passing said fouled carrier downwardly through said secondary conversion zone to said regeneration zone, regenerating carrier in said regeneration zone by reacting the coke thereon with steam and oxygen at a temperature in the range of about 1700 to 2000 F. to form said regeneration product gases, separating from said regeneration product gases said suspending gas, and circulating said carrier in said luidized bed from said upper portion through said lower portion to said regeneration zone and thence to said upper portion.

5. The process of claim 4 wherein the carrier, heavy hydrocarbon oil and suspending gas traverse said primary conversion zone as a suspension having a. velocity of at least 3 feet per second and containing not more than 10 pounds of carrier per cubic foot of suspending gas.

6. The process of claim 4 wherein heavy hydrocarbons recovered from the volatilized products are injected into said secondary conversion zone `at a level substantially below the level of entry of said fouled carrier frornsaid primary conversion zone. y 1 7. The process of claim 4 wherein the hydrogen in said primary conversion zone exerts a partial pressure in the range of about 75 to 400 p. s. i.

8. The process of claim 7 wherein the hydrogen in said secondaryeonversion zone exerts a partial pressure in the range of about 35 to 200 p. s. i.

References Cited in the le of this patent NITBD STATES PATENTS u 1Keith1 July 20, 1948 Guyer oct. 5, 194s Gom May 24, 1949 0de11 June 19,` 1951 n Bekberger Mar. 13,1956

Claims

1. A HYDROCARBON CONVERSION PROCESS WHICH COMPRISES FORMING WITH HEATED PARTICULATE CARRIER A FLUIDIZED BED DIVIDED INTO A LOWER REGENERATION ZONE AND AN UPPER SECONDARY CONVERSION ZONE, WITHDRAWING CARRIER FROM SAID SECONDARY CONVERSION ZONE, CONTACTING A HEAVY HYDROCARBON OIL OF HIGH RAMSBOTTOM CARBON RESIDUE WITH THE WITHDRAWN CARRIER AND WITH A SUSPENDING GAS CONTAINING AT LEAST 20% BY VOLUME OF HYDROGEN AND PASSING THE RESULTING SUSPENSION OF SAID OIL AND CARRIER IN DILUTE PHASE UPWARDLY THROUGH AN ELONGATED PRIMARY CONVERSION ZONE MAINTAINED AT A TEMPERATURE IN THE RANGE OF ABOUT 800 TO 1050*F. AND A PRESSURE IN THE RANGE OF ABOUT 150 TO 1000 P. S. I. G. WHEREBY SAID OIL IS CONVERTED INTO VOLATIZED PRODUCTS AND A HYDROCARBONACEOUS DEPOSIT FOULING SAID CARRIER, PASSING FOULED CARRIER FROM SAID PRIMARY CONVERSION ZONE INTO SAID SECONDARY CONVERSION ZONE AND THEREIN CONVERTING SAID HYDROCARBONACEOUS DEPOSIT INTO COKE OF LOW HYDROGEN CONTENT BY CONTACT WITH HYDROGEN-CONTAINING REGENERATION PRODUCT GASES AT A TEMPERATURE ABOUT 50 TO 200*F. ABOVE THE TEMPERATURE OF SAID PRIMARY CONVERSION ZONE, WITHDRAWING SAID VOLATILIZED PRODUCTS FOR RECOVERY WHILE LIMITING THE CONTACT THEREOF WITH SAID FLUIDIZED BED TO NOT MORE THAN THE UPPER END PORTION OF SAID SECONDARY CONVERSION ZONE, REGENERATING CARRIER IN SAID REGENERATING ZONE BY REACTING THE COKE THEREON WITH STREAM AND OXYGEN AT A TEMPERATURE IN THE RANGE OF 1600 TO 2500*F. TO FORM SAID REGENERATION PRODUCT GASES, SEPA-