Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUSRE32120 E
Publication typeGrant
Application numberUS 06/572,713
Publication dateApr 22, 1986
Filing dateJan 20, 1984
Priority dateApr 1, 1981
Publication number06572713, 572713, US RE32120 E, US RE32120E, US-E-RE32120, USRE32120 E, USRE32120E
InventorsJim Y. Low
Original AssigneePhillips Petroleum Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Hydrotreating supercritical solvent extracts in the presence of alkane extractants
US RE32120 E
Abstract
A process of recovering the hydrocarbon values from low organic carbon content deposits comprises the hydrotreating of hydrocarbons from those deposits in the presence of supercritical alkane-containing solvent.
Images(4)
Previous page
Next page
Claims(6)
I claim:
1. A process for recovering hydrocarbons from naturally-occurring low organic carbon content carbonaceous material selected from oil shale, tar sand, and mixtures thereof comprising the step of contacting said material under supercritical conditions with an added mixture of structurally analogous hydrocarbon solvents wherein at least one solvent is aromatic, at least one solvent is cycloaliphatic and is structurally analogous to the aromatic solvent, and wherein the cycloaliphatic solvent is present in an amount of 2-10% by weight based on the total solvent weight.
2. The process of claim 1 wherein the cycloaliphatic solvent is present in an amount of 5 to 10% by weight based on the total solvent weight.
3. The process of claims 1 or 2 wherein the aromatic solvent is toluene or benzene and the structurally analogous cycloaliphatic solvent is methylcyclohexane or cyclohexane.
4. The process of claims 1 or 2 further comprising the steps of hydrotreating the material in the presence of the solvent mixture and recovering the resultant hydrotreated product.
5. The process of claim 4 wherein the solvent mixture comprises toluene and methylcyclohexane. .Iadd.6. A process for recovering hydrocarbons from naturally-occurring low organic carbon content carbonaceous materials selected from oil shale, tar sand, and mixtures thereof comprising:
(a) subjecting the material to solvent extraction with an alkane-containing solvent under supercritical conditions for the solvent,
(b) then hydrotreating the extract from step (a) with added hydrogen in the presence of the solvent, and
(c) recovering the resultant hydrotreated product. .Iaddend. .Iadd.7. The process of claim 6 wherein the solvent used is n-heptane. .Iaddend. .Iadd.8. The process of claim 6 wherein the solvent employed in step (a) contains a mixture of at least one alkane and at least one aromatic compound. .Iaddend. .Iadd.9. The process of claim 6 wherein the
carbonaceous material is oil shale. .Iaddend. .Iadd.10. The process of claim 9 wherein the solvent used in step (a) is selected from the group consisting of: n-heptane and a mixture of toluene with methylcyclohexane. .Iaddend.
Description
BACKGROUND

Carbonaceous materials of low organic carbon content, such as tar sands and oil shale, are showing promise as a source of hydrocarbons.

Deposits of oil shales and tar sands have been discovered in regions of North America as well as in other parts of the world. These discoveries have sparked new scientific and commercial interest in practical methods for separating hydrocarbons from these deposits used for fuels.

OBJECT OF THE INVENTION

It is one object of the invention to provide a process for hydrotreating a low organic carbon content material in the presence of a supercritical solvent.

It is another object of the invention to extract the hydrocarbons from a low organic carbon content deposit and to hydrotreat the extract.

It is still another object of this invention to provide a method for hydrotreating tar sand or oil shale in the presence of an alkane solvent under supercritical conditions.

THE INVENTION

According to one aspect of the invention, oil shale, in any suitable physical form, is hydrogenated to produce a stock oil.

In accordance with another aspect of this invention, oil shale is subjected to supercritical solvent extraction with an alkane-containing solvent. During or after the extraction that hydrocarbon-containing fluid is hydrogenated to produce a stock oil having low nitrogen content and a high H/C ratio.

In accordance with still another aspect of this invention, oil shale is supercritically extracted with a mixture of solvents; and, during or after the extraction, the fluid is hydrogenated.

THE LOW ORGANIC CARBON CONTENT MATERIALS

By "low organic carbon content materials" is meant carbonaceous materials in which organically bound carbon constitutes about 25 weight percent or less of the material. Suitable materials include oil shale, tar sands, oil sands, and similar deposits. Coal, lignite, and other materials which contain more than 25 weight percent organically bound carbon are not included in the invention.

Some of the largest known deposits of suitable materials are shale, tar sands, oil sands, and similar deposits. Coal, lignite, and other materials which contain more than 25 weight percent organically bound carbon are not included in the invention.

Some of the largest known deposits of suitable materials are found in the Athabasca region of Alberta, Canada, and in the Western, Mid-Western, and Eastern United States. The invention is particularly effective for treating Eastern oil shales, such as Kentucky shales.

THE SUPERCRITICAL SOLVENT EXTRACTION STEP

The critical temperature for a substance is the temperature above which it cannot be liquified by an increase in pressure. Critical temperature, then, depends upon the identity of the solvent used. The supercritical extraction temperature will generally lie between the critical temperature of the solvent and 100 C. above its critical temperature. Useful extraction temperatures will generally be from about 100 C. to 600 C., with about 250 to 275 C. preferred.

The pressure at which the supercritical extraction takes place depends upon the identity of the solvent employed. The pressures used during the extraction step of the invention will range from the critical pressure of the solvent to 15,000 psi or higher. Preferred pressures lie between about 750 psi and 3,000 psi.

The liquid hourly space velocity (LHSV) employed will usually range from about 0.5 to 5. An LHSV of about 1 to 2 is preferred. Note that the space velocity can be denoted in units v/v/hr or vf /vc /hr wherein vf is the volume of fluid, vc is the volume of catalyst, and hr is hours.

The solvents used as extractants and hydrotreating media in this invention are generally alkanes, i.e., paraffins. The alkanes contain between 2 and 20 carbon atoms and are aliphatic, branched, or cyclic. Alkanes having 4 to 8 carbons are preferred. N-heptane is most preferred. Mixtures of alkanes can be used. Alternatively, the hydrotreating medium can comprise a mixture of alkanes and aromatic compounds. Suitable aromatic compounds are benzene, toluene, xylene, naphthalene, or substituted forms thereof. Various operable solvents and critical parameters therefor are given below:

______________________________________       CriticalSolvent     Temperature (C.)                     Critical Pressure (psi)______________________________________n-pentane   196.5         489n-hexane    234           437n-heptane   267           397n-octane    296           361n-nonane    321           335n-decane    344           305cyclohexane 280           591methylcyclohexane       298           504______________________________________

In a preferred embodiment, a mixture of one or more aromatic solvents and one or more structurally related paraffins, i.e., cycloaliphatic solvents is employed. The term "structurally related paraffins" refers to saturated compounds whose configurations are analogous to one or more of the aromatic solvents used. Suitable mixtures contain benzene or its substituted derivatives in combination with cyclohexane or its substituted derivatives. Useful cosolvent combinations include benzene and cyclohexane; toluene and methylcyclohexane; and xylenes and dimethylcyclohexanes. A mixture comprising toluene and methylcyclohexane is preferred.

When combinations of aromatic and structurally related paraffin solvents are employed, the concentration of paraffin solvent therein will range from 2 to 10 weight percent, with 5 to 10 weight percent preferred.

Reclaimed solvents boiling at temperatures under 150 C. are also operable.

No provision need be made for the removal of extractant or solvent before the hydrogenation step. The extractant remains in the system during hydrogenation. Preferably, little or no condensation takes place before hydrogenation.

Applicant has discovered that alkane-containing solvents are superior media for hydrotreating his carbonaceous materials. The products have higher H/C ratios and lower nitrogen contents than those produced using aromatic media such as toluene. The use of alkane solvents in both the extraction and hydrogenation steps is clearly advantageous in view of the production of lighter product with lower hydrogen consumption.

THE HYDROGENATION STEP

The hydrogenation or hydrotreating operation is carried out by contacting the material to be treated with hydrogen, preferably in the presence of at least one catalyst. The hydrogen can be introduced along with the extracting fluids, during the extraction step, or between the extraction and hydrogenation steps.

The hydrogenation will preferably take place in the presence of the supercritical extractant. The crude oil shale may be hydrogenated prior to solvent extraction but a large coke deposit formed thereby on the hydrogenation catalyst makes such hydrogenation impractical.

Useful catalysts for the hydrogenation operation include Groups VIb, VII, and VIII metals, their oxides and salts. Suitable metals are tungsten, cobalt, molybdenum, nickel, iron, platinum, and palladium. Combinations of two or more metals may also be used. A nickel-molybdenum combination, such as Nalco Ni-Mo catalyst is preferred.

The catalyst employed may be on a suitable carrier during use. Useful carriers include alumina, silica, silica-alumina, metal oxides, and mixtures of metal oxides.

The catalyst and support may be sulfided or unsulfided.

The hydrogenation step takes place under controlled conditions of temperature, pressure, and hydrogen rate. The temperature used is generally from 200 to 475 C. with 250-425 C. preferred. The pressure used will vary from 750 to 10,000 psig and will preferably be about 1,000-3,000 psig. The hydrogen rate used is between 100 and 10,000 scf/bbl., preferably 500-2,500 scf/bbl of fluid treated.

The hydrogenation step produces a mixture of alkanes having less than 0.05% sulfur and less than 0.3% nitrogen. When solvent extracted oil shale is hydrogenated in accordance with the invention, the resultant product will typically contain 0.01% or less of sulfur and 0.02% or less of nitrogen.

In combination with the hydrogenation step, other conventional operations, such as desulfurization or retorting, may be employed.

The solids and fluids produced can be separated by conventional methods. Useful devices include cyclones, filters, settling devices, or combinations thereof.

The fractions within the fluid phase can be separated via one or more conventional cooling, pressure reduction, or distillation steps. Combined methods are also operable.

EXAMPLES EXAMPLE I

Paraho shale oil blended with four times its weight of solvent under supercritical solvent conditions of 850 F. 1400 psig and 1.6 vcf /vf /hr was hydrotreated over Nalco Ni-Mo catalyst with the following results:

______________________________________  Estimated  H2 Con-          Heavy Oil Fraction*    sumption, Wt. %    Nitrogen,                              Sulfur,                                    H/CSolvent  scf/bbl   of Feed  ppm    Wt. % Ratio______________________________________Toluene  2600      47       3149   01    1.66N--Heptane    1200      36       1595   01    1.79N--Heptane    1200      37       1990   01    1.82______________________________________ *Oil boiling above 310 F.

This example shows the surprising and beneficial results favoring carrying out the process with paraffinic solvent including: (1) lower hydrogen consumption, (2) reduced heavy oil in the product (higher conversion) and (3) better heavy oil properties (lower nitrogen, higher H/C ratio).

EXAMPLE II

Paraho shale oil was hydrotreated over Nalco Ni-Mo catalyst under conditions similar to those in Example I except the first run was conducted without supercritical solvent.

______________________________________            88-Hr. Run                    154-Hr. Run            Without With n-C7            Solvent Solvent______________________________________Oil Conversion, %  65-85     75-90Yield, % of Feed:Gases              20-30      5-10Liquids Boiling above 310 F.              50-60     70-80Coke               0.84      0.48______________________________________

This example shows that conventional hydrotreating without supercritical solvent produced about three times as much gas and almost twice as much coke while operating at lower conversion.

EXAMPLE III

The following runs used Paraho shale oil dissolved in four times its weight of solvent. Hydrotreatment at 850 F., 1400 psig. 1.6 LHSV feed rate, 300 GHSV hydrogen, Ni-Mo on alumina catalyst.

______________________________________  H2                 MCH2 in  Con-   Heavy Oil Fraction1                          Reclaimed    sumption Wt. %   Nitrogen                            Sulfur                                  SolventSolvent  scf/bbl  of feed ppm    ppm   Wt. %______________________________________Toluene  3200     37      4.430  50    7.57Toluene  3700     32      5.030  50    5.50Toluene  2200     40      6.710  30    6.24w/5% MCH2Toluene  2000     33      9.116  .sup. NA3                                  6.84w/5% MCHToluene  2000     39      10.770 NA    5.27w/5% MCHToluene  1200     39      10.216 NA    4.95______________________________________ 1 Fraction boiling above 320 F. 2 Methylcyclohexane 3 Not applicable

The data show that in runs with toluene only as the solvent, about 5-7 percent of the solvent is hydrogenated to methylcyclohexane. It runs with mixed solvent very little solvent is hydrogenated and hydrogen consumption is substantially reduced. Conversion to heavy oil fraction and reduction of nitrogen and sulfur were not materially affected. These data indicate that, with close control of process conditions and mixed (aromatic-cyclic) solvent composition, hydrogenation of the solvent can be substantially avoided.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US861027 *Nov 21, 1905Jul 23, 1907William J GustinRailway-signal.
US2118940 *Jan 29, 1936May 31, 1938Standard Ig CoDestructive hydrogenation of distillable carbonaceous material
US2270674 *Apr 25, 1936Jan 20, 1942Shell DevMethod of separating high molecular mixtures
US2793104 *Dec 29, 1952May 21, 1957Texaco Development CorpProcess for the recovery of oil from oil-bearing minerals
US3421868 *Mar 19, 1964Jan 14, 1969Inst Gas TechnologyFree fall shale hydrogasification
US3594305 *Jan 23, 1970Jul 20, 1971Sun Oil CoProcess for hydrogenation of coal
US3607717 *Jan 9, 1970Sep 21, 1971Kerr Mc Gee Chem CorpFractionating coal liquefaction products with light organic solvents
US3813329 *Aug 18, 1972May 28, 1974Universal Oil Prod CoSolvent extraction of coal utilizing a heteropoly acid catalyst
US3929193 *Sep 23, 1974Dec 30, 1975Marathon Oil CoRecovery of organic matter from organic mineral-containing deposits
US3970541 *Nov 26, 1974Jul 20, 1976Coal Industry (Patents) LimitedGas extraction of coal
US3997424 *Nov 12, 1974Dec 14, 1976Coal Industry (Patents) LimitedCarbon monoxide, water, solvent
US4019975 *Oct 29, 1974Apr 26, 1977Coal Industry (Patents) LimitedSolvent extraction, non-noble metal salt or oxide as catalyst
US4083769 *Nov 30, 1976Apr 11, 1978Gulf Research & Development CompanyMultistage, preheating, hydrocracking, hydrogenation
US4108760 *Jul 24, 1975Aug 22, 1978Coal Industry (Patents) LimitedGaseous solvent
US4155832 *Dec 23, 1977May 22, 1979The United States Of America As Represented By The United States Department Of EnergyHydrogenation process for solid carbonaceous materials
US4158638 *Mar 27, 1978Jun 19, 1979Gulf Research & Development CompanyRecovery of oil from oil shale
US4197183 *Feb 7, 1979Apr 8, 1980Mobil Oil CorporationProcessing of tar sands
US4297200 *Jan 18, 1980Oct 27, 1981Briley Patrick BMethod for hydroconversion of solid carbonaceous materials
US4303495 *Sep 7, 1979Dec 1, 1981Kraftwerk Union AktiengesellschaftRecovery of liquid and gaseous hydrocarbons from raw materials containing hydrocarbons such as oil shale and coal
US4354922 *Mar 31, 1981Oct 19, 1982Mobil Oil CorporationProcessing of heavy hydrocarbon oils
US4363717 *Jan 15, 1981Dec 14, 1982Mobil Oil CorporationUpgrading to motor fuels using a metal halide catalyst
US4390411 *Apr 2, 1981Jun 28, 1983Phillips Petroleum CompanyRecovery of hydrocarbon values from low organic carbon content carbonaceous materials via hydrogenation and supercritical extraction
GB493307A * Title not available
Non-Patent Citations
Reference
1"Supercritical Gas Extraction Commercial", Process Engineering (8/77), p. 6.
2 *Supercritical Gas Extraction Commercial , Process Engineering (8/77), p. 6.
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4983278 *Apr 3, 1989Jan 8, 1991Western Research Institute & Ilr Services Inc.Pyrolysis methods with product oil recycling
US6428686 *Jun 22, 2000Aug 6, 2002Process Dynamics, Inc.Mixing and/or flashing hydrogen and oil to be treated in presence of solvent or diluent in which hydrogen solubility is high relative to oil feed so that hydrogen is in solution
US6881326Jun 3, 2002Apr 19, 2005Process Dynamics, Inc.Mixing or flashing hydrogen and oil in presence of solvent or diluent; trickle bed reactor replaced by smaller tubular reactor; hydrocracking, hydroisomerization and hydrodemetalization
US7144498Jan 30, 2004Dec 5, 2006Kellogg Brown & Root LlcSupercritical hydrocarbon conversion process
US7291257Dec 9, 2004Nov 6, 2007Process Dynamics, Inc.Mixing, flashing hydrogen with oil in presence of catalyst, solvent, diluent; process control
US7811444Jun 8, 2006Oct 12, 2010Marathon Oil Canada Corporationoxidation products acts as a solvent or miscibility agent for the separated asphaltenes composition and the oxidizing agent; tar sand; breaks aromatic bonds
US7833408Dec 26, 2007Nov 16, 2010Kellogg Brown & Root LlcMinimizing initial capital costs; includes gasification of heavy feedstocks for energy production and cash generation to finance later stages; regenerating and recycling coked noncatalytic solids
US7909985Dec 23, 2005Mar 22, 2011University Of Utah Research FoundationFragmentation of heavy hydrocarbons using an ozone-containing fragmentation fluid
US8529687Aug 26, 2010Sep 10, 2013Marathon Oil Canada CorporationOxidation of asphaltenes
Classifications
U.S. Classification208/390, 208/323, 208/211, 208/238, 208/254.00H, 208/433, 208/430, 208/952, 208/412, 208/213, 208/431, 208/432
International ClassificationC10G1/00, B01D11/02, C10G1/04
Cooperative ClassificationC10G1/002, C10G1/04, B01D11/0203
European ClassificationC10G1/00B, B01D11/02B, C10G1/04