|Publication number||US3894938 A|
|Publication date||Jul 15, 1975|
|Filing date||Jun 15, 1973|
|Priority date||Jun 15, 1973|
|Also published as||CA1024091A1, DE2428463A1, DE2428463C2|
|Publication number||US 3894938 A, US 3894938A, US-A-3894938, US3894938 A, US3894938A|
|Inventors||Robert L Gorring, George F Shipman|
|Original Assignee||Mobil Oil Corp|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (6), Referenced by (69), Classifications (13)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent [1 1 Gorring et al.
[ 1 July 15, 1975 CATALYTIC DEWAXING OF GAS OILS  Assignee: Mobil Oil Corporation, New York,
 Filed: June 15, 1973  App]. N0.: 370,265
 US. Cl.
 Int. Cl. C10G 37/00  Field of Search 208/97, 46
 References Cited UNITED STATES PATENTS 3,438,887 4/1969 Morris et a1. 208/97 3,472,759 10/1969 Masolocites et a1. 208/97 3,516,925 6/1970 Lawrence et a1. v 208/46 3668113 6/1972 Burbidge et a1. 208/97 3,700,585 10/1972 Chen et a1. 208/111 3,764,516 10/1973 Steinmetz et a1. 208/97 FOREIGN PATENTS OR APPLICATIONS 884,752 12/1961 United Kingdom 208/97 1,191,471 5/1970 United Kingdom 208/97 Primary Examiner'-De1bert E. Gantz Assistant Examiner' lames W. l-lellwege Attorney, Agent, or FirmCharles A. l-luggett; Michael G. Gilman ABSTRACT Improved catalytic dewaxing and desulfurization of high pour point, high sulfur gas oils to lower their pour point to.about 10F or lower and their sulfur content by contacting a high pour point gas oil first with a ZSM-S type zeolite hyd'rodewaxing catalyst which may contain a hydrogenation/dehydrogenation component, in the presence or absence of added hydrogen under low pressure conditions, followed by conventional hydrodesulfurization processing of the dewaxed intermediate.
4 Claims, N0 Drawings 1 CATALYTTC DEWAXING OF GAS OILS This invention relates to petroleum processing. It more particularly refers to upgrading certain gas oil fractions to low pour point fuels.
Liquid hydrocarbons in the 400 to 850F boiling range include kerosine, Diesel fuel and No. 2, or home heating fuel. Petroleum fractions boiling in this range often have a significant long chain paraffin content which accounts for their rather high pour point. lt is not unusual for fractions of this type to have pour points in the 50 to lOF range. One significant specification for some No. 2 fuel oil is a pour point of 0F or lower. Thus reduction in pour point is accomplished by dewaxing or removing the long chain normal paraffins which seem to be principally responsible for this property.
This dewaxing has traditionally been accomplished by a solvent dewaxing technique according to which the gas oil is thoroughly mixed with a suitable solvent, often methyl ethyl ketone, into which the wax dissolves. ln the past, the wax was recovered from the solvent, by evaporation of the ketone, purified and sold for seals, candles and other uses. More recently, the petroleum industry has seen a marked decline in this market and has therefore sought more profitable and less costly outlets for this wax constituent.
It has therefore been proposed to use shape selective zeolitic catalysts to crack, preferably hydroerack, these paraffinic components and convert them into smaller, suitably paraffinic fragments which may be collected as light gas, or larger but not waxy paraffinic materials which remain in the boiling range of the gas oil being treated and therefore enhance the yield of the dewaxing operation. The smaller cracked fragments may be used as fuel, sold as such or resolved and disposed of by components.
Most recently it has been proposed to utilize the new ZSM-S type of zeolite as a cracking or hydrocracking dewaxing catalyst because it converts not only the normal paraffins but the slightly branched paraffins as well thereby more efficiently lowering the pour point of the product with better yields than have heretofore been achieved. (See US. Pat. No. 3,700,585).
ZSM-S type of zeolite is a group of small pored zeoiites, the most noteworthy members of which are ZSM- 5, ZSM-8 and ZSM-l 1. US. Pat. Nos. 3,702,886 directed to ZSlVl-S zeolite and 3,709,979 directed to ZSM-l l zeolite are in point and are incorporated herein by reference. Abandoned US. Patent application Ser. No. 865,418, filed Oct. 10, I969 is directed to ZSM-S and is also in point and is incorporated herein by reference. The ZSM-S family of zeolites can be used to catalyze cracking of normal or slightly branched paraffins in the absence of added hydrogen or to catalyze hydroeracking of such paraffins in the presence of added hydrogen. Typical cracking conditions include a space velocity of about 0.25 to 200 LHSV, a temperature of about 400F to l 100F and a pressure from subatmospheric to several hundred atmospheres. Typical hydrocracking conditions include a space velocity of about 0.1 to 10 LHSV, a hydrogen to hydrocarbon mole ratio of about 1 to to l, a temperature of about 650F to 1000F and a pressure of about l00 to 3000 psig (see US Patent 3,700,585).
For most petroleum processing, it is conventional to pretreat the charge stock in some manner calculated to remove sulfur and/or metals and/or nitrogen from the charge stock prior to converting and upgrading such charge stock. Thus catalytic hydrodesulfurization is a unit process whichis widely used in a refinery. lt precedes reforming and other conversion processes because sulfur, nitrogen and/or metals present in the charge stock often have detrimental effects upon hydrocarbon conversion catalysts. Metals, sulfur and nitrogen tend to concentrate in the heavier petroleum fractions. Therefore conversion processes utilizing such heavier petroleum fractions would normally be considered prime users of the conventional desulfurization followed by catalytic conversion processing sequenee.
Thus in the dewaxing of sulfur containing gas oils boiling in the 400 to 900F range, or any part thereof, one of ordinary skill in the art would conventionally think of subjecting such gas oils to catalytic hydrodesulfurization prior to dewaxing. Indeed this may be a desirable modus operandi for dewaxing of gas oils with a conventional shape selective catalyst of the erionite type. It has been most unexpectedly found however that operating according to this sequence with ZSM-S type zeolite dewaxing catalyst leads to a significantly decreased activity as compared to what one would expect (see Examples l and 2 infra). In fact the evidence would seem to lead one to the conclusion that the more sulfur and/or nitrogen there is in the gas oil charge stock, the greater is the diminution of ZSM-5 type zeolite catalyst life. Yet the product finally produced as a result of this dewaxing operation must have a reduced sulfur and/or nitrogen content or preferably substantially no sulfur or nitrogen content at all. This is because this product goes predominantly into the jet fuel, Diesel fuel and home heating market, where nitrogen and sulfur emissions must be closely controlled.
It is therefore an important object of this invention to provide an efficient gas oil dewaxing, desulfurization and denitrogenation process.
It is another object of this invention to provide such a process capable of taking advantage of the use of ZSM-5 type of zeolite dewaxing catalyst.
It is a further object of this invention to provide such a process for producing high yields of No. 2 fuel oil having a pour point of about 0F.
Other and additional objects of this invention will become apparent from a consideration of this entire specification including the claims hereof.
In accord with and fulfilling these objects, one important aspect of this invention resides in a processing sequence consisting essentially of catalytically dewaxing a sulfur and/or nitrogen containing gas oil having a boiling range in the range of about 400F to 900F and thence subjecting at least the liquid product resulting from such dewaxing to desulfurization and/or denitrogenation. In a preferred aspect of this invention the gas oils to which this process is directed have a total sulfur and nitrogen content of at least 0.1 wt. percent and 10 ppm, respectively, and a pour point of at least +20F. It is preferred to use a ZSM-S type of zeolite catalyst for dewaxing and to operate the dewaxing portion of this process at about 300 to l000F, 0 to 2000 psig, 0.1 to 10 LHSV and a hydrogen to hydrocarbon ratio of about 0 to 25 to 1. Where the dewaxing portion of the process is of the hydrodewaxing type, the ZSM-S type zeolite may have incorporated therein a hydrogen transfer functional component such as nickel, palladium, or platinum in a proportion of about 0.5 to 5 weight percent based on the total weight of dewaxing catalyst. The dewaxing catalyst may be used in a fixed or fluidized bed configuration as desired. In a fixed bed operation, the catalyst particles should be sized be tween one thirty-second and one-eighth inch. in a fluidized bed the catalyst particles should be about 80 to 400 mesh. The catalyst may be of the matrix type with alumina, silica, silica-alumina or other similar known matrix materials. In this matrix embodiment. the ZSM- type'zeolite should constitute about 5 to 95 weight percent of the total catalyst matrix.
' The product of catalytic dewaxing may be resolved into a liquid and gas portion by cooling to a prescribed temperature at an appropriate pressure to obtain what ever liquid-gas demarcation is desired. The liquid may then be subjected to desulfurization and denitrogenation. It is preferred however to subject the entire de waxed product, without intermediate product resolution, to desulfurization and denitrogenation. By not resolving the intermediate product there is obtained a great saving in energy, particularly heat, because this resolution requires cooling and the subsequent desulfurization and denitrogenation requires reheating. Desulfurization and denitrogenation are usually accomplished simultaneously, one treatment serving to liberate both sulfur and nitrogen from the feed stock. This treatment can be carried out in any manner desired, e.g. conventionally at about 550 to 800F, 200 to l000 psig, 0.5 to 4.0 LHSV. 2 to moles of added hydrogen per mole of feed stock, in effective contact with a cobalt-molybdenum-alumina-catalyst. This procedure converts sulfur and nitrogen values in the feed stock to hydrogen sulfide and ammonia which are later recovered from the gaseous portion of the final product.
While operating in the manner and sequence set forth results in excellent dewaxing and pour point reduction to acceptable levels with liquid yields of over about 80 percent and dewaxing catalyst life of about to 400 days between regenerations to a total life of about 6 to 60 months, reversing the sequence of operations, that is desulfurizing and denitrogenating under the same conditions as set forth above and directly dewaxing the intermediate product thus formed to the same final product specifications. permitted operation of the dewaxing catalyst for about 1 to 24 hours between regenerations.
This invention will be illustrated by the following Examples which are not to be considered as limiting on the scope or applicability thereof. In these Examples parts and percentages are by weight unless expressly stated to be on some other basis.
EXAMPLE 1 (PRIOR ART) A gas oil having a boiling range of 500 to 800F, a
pour point of +50F, a sulfur content of less than 3 wt. 7( and a nitrogen content of less than 3000 ppm was contacted with ZSM5 zeolite at 700F. 400 psig. 5.0 hydrogen to hydrocarbon mole ratio and 3.0 LHSV. The conversion to 330F liquid was 84 percent with the pourpoint reduced to 0F. Time between catalyst regenerations was 20 days.
EXAMPLE 2 (PRIOR ART) A gas oil having a boiling range of 500 to 800F, a pour point of +50F, a sulfur content of 2.5 percent and a nitrogen content of 0.02 percent was contacted with a cobalt-molybdenum-alumina catalyst at 700F, 400 psig, 5.0 hydrogen to hydrocarbon ratio and 1.0 LHSV. The product thus formed was directly, and without intermediate product resolution. contacted with ZSM-5 zeolite at 700F. 400 psig. 50 hydrogen to hydrocarbon mole ratio and 3.0 LHSV. The yield of 330F liquid was 96 percent. However. its pour point was reduced only from +50F to +25F, indicating that the ZSM-S dewaxing catalyst was substantially deactivated.
EXAMPLE 3 Example 2 was exactly repeated except that the sequence of processing steps was reversed. The yield of 330F+ liquid was 84 percent and the pour point was reduced from +50F to 0F. Time between ZSM-5 catalyst regenerations was 20 days.
What is claimed is:
1. In the process of reducing the pour point of a sulfur and nitrogen containing gas oil boiling in the range of 400 to 900F by treating such with a ZSM-S type of zeolite at about 300 to I000F; the improvement, whereby reducing the pour point of said gas oil and purifying such to reduce the sulfur and nitrogen content thereof, which comprises subjecting said gas oil first to said zeolite treatment and then subjecting the whole, unresolved zeolite treated, reduced pour point intermediate to desulfurization and denitrogenation.
2. The improved process claimed in claim 1 wherein said hydrodesulfurization is carried out at about 550 to 800F, 200 to l000 psig hydrogen partial pressure, 0.5 to 4.0 LHSV and in effective contact with a cobaltmolybdenum-alumina catalyst.
3. The improved process claimed in claim 1 wherein said gas oil has a minimum of 0.1 wt. percent total sulfur and 10 ppm nitrogen before processing.
4. The improved process claimed in claim 1 wherein said zeolite treating is carried out at a hydrogen partial pressure of about 0 to 2000 psig and a space velocity of about 0.1 to 10 LHSV.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3438887 *||Jul 11, 1967||Apr 15, 1969||Texaco Inc||Production of lubricating oils|
|US3472759 *||Apr 25, 1967||Oct 14, 1969||Atlantic Richfield Co||Process for removal of sulfur and metals from petroleum materials|
|US3516925 *||Feb 25, 1965||Jun 23, 1970||British Petroleum Co||Catalytic conversion of hydrocarbons|
|US3668113 *||Sep 22, 1969||Jun 6, 1972||British Petroleum Co||Hydrocatalytic process for normal paraffin wax and sulfur removal|
|US3700585 *||Oct 10, 1969||Oct 24, 1972||Mobil Oil Corp||Dewaxing of oils by shape selective cracking and hydrocracking over zeolites zsm-5 and zsm-8|
|US3764516 *||Apr 24, 1972||Oct 9, 1973||Furukawa Electric Co Ltd||Isomerization of waxy lube streams and waxes using zeolite catalyst|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3980550 *||Dec 8, 1975||Sep 14, 1976||Mobil Oil Corporation||Catalytic hydrodewaxing|
|US4137148 *||Jul 20, 1977||Jan 30, 1979||Mobil Oil Corporation||Manufacture of specialty oils|
|US4171257 *||Oct 23, 1978||Oct 16, 1979||Chevron Research Company||Petroleum distillate upgrading process|
|US4176050 *||Dec 4, 1978||Nov 27, 1979||Mobil Oil Corporation||Production of high V.I. lubricating oil stock|
|US4181598 *||Dec 20, 1977||Jan 1, 1980||Mobil Oil Corporation||Manufacture of lube base stock oil|
|US4282085 *||May 21, 1979||Aug 4, 1981||Chevron Research Company||Petroleum distillate upgrading process|
|US4292166 *||Jul 7, 1980||Sep 29, 1981||Mobil Oil Corporation||Catalytic process for manufacture of lubricating oils|
|US4313817 *||Jun 16, 1980||Feb 2, 1982||Chevron Research Company||Hydrocarbon conversion catalyst and process using said catalyst|
|US4332670 *||Jan 14, 1981||Jun 1, 1982||Mobil Oil Corporation||Catalytic dewaxing of middle distillates|
|US4357232 *||Jan 15, 1981||Nov 2, 1982||Mobil Oil Corporation||Method for enhancing catalytic activity|
|US4358362 *||Jan 15, 1981||Nov 9, 1982||Mobil Oil Corporation||Method for enhancing catalytic activity|
|US4358363 *||Jan 15, 1981||Nov 9, 1982||Mobil Oil Corporation||Method for enhancing catalytic activity|
|US4400265 *||Apr 1, 1982||Aug 23, 1983||Mobil Oil Corporation||Cascade catalytic dewaxing/hydrodewaxing process|
|US4419220 *||May 18, 1982||Dec 6, 1983||Mobil Oil Corporation||Catalytic dewaxing process|
|US4440630 *||Sep 30, 1982||Apr 3, 1984||Mobil Oil Corporation||Process for simultaneous hydrodesulfurization and hydrodewaxing with a catalyst of controlled pore size and metals content|
|US4458024 *||Feb 8, 1982||Jul 3, 1984||Mobil Oil Corporation||Process for hydrotreating petroleum residua and catalyst therefor|
|US4490242 *||Jan 13, 1984||Dec 25, 1984||Mobil Oil Corporation||Two-stage hydrocarbon dewaxing hydrotreating process|
|US4518703 *||Dec 6, 1982||May 21, 1985||Union Oil Company Of California||Crystalline silica catalysts|
|US4549955 *||Nov 30, 1984||Oct 29, 1985||Mobil Oil Corporation||Process for stabilizing hydroprocessed lubricating oil stocks by the addition of hydrogen sulfide|
|US4564440 *||Jul 11, 1983||Jan 14, 1986||Mobil Oil Corporation||Viscosity index improvement in dewaxed lube basestock by partial desulfurization in hydrotreat bed|
|US4568655 *||Oct 29, 1984||Feb 4, 1986||Mobil Oil Corporation||Catalyst composition comprising Zeolite Beta|
|US4599162 *||Dec 21, 1984||Jul 8, 1986||Mobil Oil Corporation||Cascade hydrodewaxing process|
|US4600497 *||May 8, 1981||Jul 15, 1986||Union Oil Company Of California||Process for treating waxy shale oils|
|US4601993 *||Oct 17, 1984||Jul 22, 1986||Mobil Oil Corporation||Catalyst composition dewaxing of lubricating oils|
|US4610778 *||Jun 3, 1985||Sep 9, 1986||Mobil Oil Corporation||Two-stage hydrocarbon dewaxing process|
|US4664775 *||Jul 26, 1983||May 12, 1987||Toa Nenryo Kogyo Kabushiki Kaisha||Method for manufacturing low pour point petroleum product with zeolite TSZ|
|US4696732 *||Feb 14, 1986||Sep 29, 1987||Mobil Oil Corporation||Simultaneous hydrotreating and dewaxing of petroleum feedstocks|
|US4700562 *||Jan 8, 1986||Oct 20, 1987||Mobil Oil Corporation||Method for determining effectiveness of catalytic dewaxing reactor|
|US4711710 *||Dec 5, 1986||Dec 8, 1987||Mobil Oil Corporation||Process for making improved lubricating oils from heavy feedstock|
|US4740292 *||Oct 15, 1986||Apr 26, 1988||Mobil Oil Corporation||Catalytic cracking with a mixture of faujasite-type zeolite and zeolite beta|
|US4743354 *||Oct 10, 1986||May 10, 1988||Union Oil Company Of California||Process for producing a product hydrocarbon having a reduced content of normal paraffins|
|US4743355 *||Jun 2, 1986||May 10, 1988||Union Oil Company Of California||Process for producing a high quality lube oil stock|
|US4767522 *||Jul 6, 1987||Aug 30, 1988||Mobil Oil Corporation||Distillate dewaxing process with mixed zeolites|
|US4790927 *||Jan 9, 1984||Dec 13, 1988||Union Oil Company Of California||Process for simultaneous hydrotreating and hydrodewaxing of hydrocarbons|
|US4795546 *||Jul 28, 1987||Jan 3, 1989||Chevron Research Company||Process for stabilizing lube base stocks derived from neutral oils|
|US4846959 *||Aug 18, 1987||Jul 11, 1989||Mobil Oil Corporation||Manufacture of premium fuels|
|US4853103 *||Apr 11, 1988||Aug 1, 1989||Mobil Oil Corporation||Lube catalytic dewaxing-hydrotreating process|
|US4869806 *||Mar 10, 1989||Sep 26, 1989||Mobil Oil Corp.||Production of high viscosity index lubricating oil stock|
|US4877762 *||Aug 22, 1988||Oct 31, 1989||Union Oil Company Of California||Catalyst for simultaneous hydrotreating and hydrodewaxing of hydrocarbons|
|US4913797 *||Jan 12, 1989||Apr 3, 1990||Mobil Oil Corporation||Catalyst hydrotreating and dewaxing process|
|US4919788 *||Oct 21, 1988||Apr 24, 1990||Mobil Oil Corporation||Lubricant production process|
|US4952303 *||Dec 22, 1988||Aug 28, 1990||Mobil Oil Corp.||Process for preparing a very high quality lube base stock oil|
|US4960504 *||Feb 22, 1988||Oct 2, 1990||Uop||Dewaxing catalysts and processes employing silicoaluminophosphate molecular sieves|
|US4986894 *||Mar 19, 1990||Jan 22, 1991||Mobil Oil Corp.||Catalytic hydroisomerization process|
|US4994168 *||Oct 21, 1988||Feb 19, 1991||Mobil Oil Corporation||Lube oil product stripping|
|US5015361 *||Jan 23, 1989||May 14, 1991||Mobil Oil Corp.||Catalytic dewaxing process employing surface acidity deactivated zeolite catalysts|
|US5332490 *||Sep 28, 1992||Jul 26, 1994||Texaco Inc.||Catalytic process for dewaxing hydrocarbon feedstocks|
|US5391286 *||Nov 3, 1993||Feb 21, 1995||Texaco Inc.||Process for catalytic dewaxing of hydrocarbon feedstocks|
|US5614079 *||Sep 29, 1994||Mar 25, 1997||Mobil Oil Corporation||Catalytic dewaxing over silica bound molecular sieve|
|US5833837 *||Sep 29, 1995||Nov 10, 1998||Chevron U.S.A. Inc.||Process for dewaxing heavy and light fractions of lube base oil with zeolite and sapo containing catalysts|
|US5846503 *||May 19, 1992||Dec 8, 1998||Mobil Oil Corporation||Process for rejuvenating used alkanolamaine solutions|
|US5855767 *||Sep 26, 1994||Jan 5, 1999||Star Enterprise||Hydrorefining process for production of base oils|
|US6051129 *||Jul 24, 1998||Apr 18, 2000||Chevron U.S.A. Inc.||Process for reducing haze point in bright stock|
|US6068757 *||Nov 3, 1995||May 30, 2000||Coastal Eagle Point Oil Company||Hydrodewaxing process|
|US6294077||Feb 2, 2000||Sep 25, 2001||Mobil Oil Corporation||Production of high viscosity lubricating oil stock with improved ZSM-5 catalyst|
|US6399845||May 28, 1998||Jun 4, 2002||Fortum Oil & Gas Oy||Process for producing high grade diesel fuel|
|US6656342 *||Apr 4, 2001||Dec 2, 2003||Chevron U.S.A. Inc.||Graded catalyst bed for split-feed hydrocracking/hydrotreating|
|US6699385||Oct 17, 2001||Mar 2, 2004||Chevron U.S.A. Inc.||Process for converting waxy feeds into low haze heavy base oil|
|US7077948 *||Nov 16, 1999||Jul 18, 2006||Shell Oil Company||Catalytic dewaxing process|
|US7955401||Jul 16, 2007||Jun 7, 2011||Conocophillips Company||Hydrotreating and catalytic dewaxing process for making diesel from oils and/or fats|
|US9039892||Sep 5, 2012||May 26, 2015||Syed Tajammul Hussain||Nano catalytic dewaxing of heavy petroleum wastes (>C-23 alkanes)|
|DE2831968A1 *||Jul 20, 1978||Feb 8, 1979||Mobil Oil Corp||Verfahren zur herstellung von qualitativ hochwertigem spezialoel|
|DE2854258A1 *||Dec 15, 1978||Jun 21, 1979||Mobil Oil Corp||Verfahren zur herstellung von qualitativ hochwertigem schmiergrundlagenoel|
|DE2929412A1 *||Jul 20, 1979||Apr 30, 1980||Chevron Res||Verfahren zur verbesserung eines erdoeldestillats|
|DE3010094A1 *||Mar 15, 1980||Oct 2, 1980||Chevron Res||Katalysator zur kohlenwasserstoffumwandlung|
|EP0027380A1 *||Oct 14, 1980||Apr 22, 1981||Mobil Oil Corporation||A method of preparing a metal-containing zeolite catalyst and the use of the catalyst in dewaxing gas oil|
|EP0091252A1 *||Mar 28, 1983||Oct 12, 1983||Mobil Oil Corporation||Two-step catalytic hydrodewaxing-hydrodesulfurization process|
|EP0180354A1 *||Oct 10, 1985||May 7, 1986||Mobil Oil Corporation||Process for hydrotreating and dewaxing petroleum feedstocks|
|EP1462168A1||Mar 11, 2004||Sep 29, 2004||Institut Français du Pétrole||Catalyst and its use for improving the pour point of hydrocarbon feedstocks|
|U.S. Classification||208/97, 208/111.35, 208/111.3, 208/59|
|International Classification||C10G65/00, C10L1/04, C10G73/02, C10G45/64, C10G65/04, C10G69/04|
|Cooperative Classification||C10G65/043, C10G2400/06|