Mineral oils: processes and products – By treatment of solid mineral – e.g. – coal liquefaction – etc. – Including contact of feed with liquid produced in the...
Reexamination Certificate
2000-03-09
2001-11-20
Griffin, Walter D. (Department: 1764)
Mineral oils: processes and products
By treatment of solid mineral, e.g., coal liquefaction, etc.
Including contact of feed with liquid produced in the...
C208S390000, C208S412000
Reexamination Certificate
active
06319395
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a continuous process for producing synthetic crude oil (SCO) from oil shale or tar sand and an apparatus for its practice. More specifically, the present invention provides a process for treating dry tar sand or shale without prior beneficiation, in a reactor operating at elevated pressure and temperature conditions, in the presence of substantially only hydrogen gas.
BACKGROUND OF THE INVENTION
There are some tar sand systems that are successful in making synthetic crude oil (SCO), such as those in the Canadian Athabasca tar sand area that surface mine and process the tar sands, where they first separate sand (85%) from bitumen (15%) to avoid processing the sand in the reaction systems. The separated bitumen is converted to sweet, light crude oil by conventional refinery type operation. Separation of the sand from the bitumen requires beneficiating operations such as floatation cells and secondary separation equipment and processing and equipment to prepare the tar sand for flotation. In these systems, tailing oil recovery is necessary to clear the sand for disposal, however the sand is not completely cleared of bitumen.
Existing technology uses a large number of physical and chemical processing units for the treatment of wet tar sands, e.g., fluid cokers, LC finer, tumblers (being phased out by hydro-pumping), beneficiators including: primary separation vessels with floatation cells and secondary separation systems necessary to recover the bitumen from the tar sand; tailing oil recovery systems which result from the sand not being completely cleared of bitumen; tailing settling ponds which are necessary to settle and separate fine clays and other undesirable solids from the water required for floatation since the water must be reused to maximize clean-up to reduce environmental problems. These systems require large facilities along with the maintenance and reclamation required.
For example, U.S. Pat. Nos. 5,340,467 and 5,316,467 to Gregoli, et al. relate to the recovery of hydrocarbons (bitumen) from tar sands. In the Gregoli, et al. patent process, tar sand is slurried with water and a chemical additive and then the slurry is sent to a separation system. The bitumen recovery from tar sand processes described in U.S. Pat. No. 5,143,598 to Graham et al. and U.S. Pat. No. 4,474,616 to Smith, et al. also involve the formation of aqueous slurries. Other processes involving slurries, digestion, or extraction processes are taught in U.S. Pat. No. 4,098,674 to Rammler, et al., U.S. Pat. No. 4,036,732 to Irani, et al., U.S. Pat. No. 4,409,090 to Hanson, et al., U.S. Pat. No. 4,456,536 to Lorenz, et al. and Miller, et al.
In situ processing of tar sand is also known as seen from the teachings of U.S. Pat. Nos. 4,140,179, 4,301,865 and 4,457,365 to Kasevich, et al. and U.S. Pat. No. 3,680,634 to Peacock, et al.
U.S. Patent No. 4,094,767 to Gifford relates to fluidized bed retorting of tar sands. In the process disclosed by the Gifford patent, raw tar sand is treated in a fluidized bed reactor in the presence of a reducing environment, steam, recycle gases and combustion gases. The conversion of the bitumen, according to the Gifford patent, is through vaporization and cracking, thereby leaving a coked sand product. The steam and oxygen, according to Gifford are “injected into the fluidized bed in the decoking area above the spent sand cooling zone, and below the input area in the cracking zone for fresh tar sand.”
The process and apparatus of the present invention avoid the use of the large number of physical and chemical processing units used in the processing of wet tar sand by using a single continuous reactor system to hydrocrack and hydrogenate the dry tar sand. Moreover, because the present invention directly hydrogenates dry tar sand, larger quantities of valuable sweet, light crude oil are obtained. Moreover, with the present invention, less gas and substantially no coke is produced.
BRIEF SUMMARY OF THE INVENTION
The present invention relates to a continuous process for converting oil bearing material, e.g., oil shale or tar sand, and an apparatus for its practice.
Accordingly, one aspect of the present invention is to provide a continuous process and an apparatus for its practice where oil bearing material such as the kerogen in oil shale or the bitumen in tar sand is continuously treated.
Another aspect of the present invention relates to the treatment of dry tar sand.
An object of the present invention is providing a method and apparatus for converting a tar sand or shale feed to oil which can be conducted in the absence of a benificiation processes such as, for example, a hot-water extraction process to separate sand or other non reacting solids from bituminous or oil-bearing material in the feed.
An object of the present invention is providing a process for converting tar sand to oil through the use of substantially only hydrogen.
Another object of the present invention is providing a heat recovery process whereby hydrogen provides the heat necessary to bring the raw tar sand up to reactor temperature.
A still further object of the present invention is providing a process where hydrogen is used for hydrocracking and hydrogenating the bitumen in the tar sand or oil shale.
A further objective of the present invention is providing a process for using recycle and make-up hydrogen as a heat transfer vehicle.
A still further object of the present invention is providing an improved process for producing oil from tar sand or shale by reacting the tar sand or shale with substantially only hydrogen in a fluidized bed reactor, wherein the fluidizing medium is substantially hydrogen.
Yet another object of the present invention is providing a fluidized bed process where one inch or less size tar sand or shale pieces are fed into a fluidized bed reactor near the bottom of the reactor and spent sand and reaction products are removed from near the top of the reactor.
Still another object of the present invention is providing a method of recycling unreacted hydrogen that exits a reactor in which tar sand or oil shale is converted to oil. The method includes purging impurities in the exiting recycle hydrogen stream by pressure swing adsorption, maintaining the hydrogen at more than about 450 psi throughout the recycle process, admixing fresh hydrogen to the recycle hydrogen stream to form a mixture, and feeding the mixture into the reactor.
These objectives can be achieved by providing a process for producing oil from an oil bearing feed such as tar sand or oil shale. The process comprises introducing the feed in a fluidizable form into a fluidized bed reactor. A fluidizing medium enters the fluidized bed reactor where it contacts and fluidizes the fluidizable feed. The fluidizing medium includes at least hydrogen. The fluidized feed forms a fluidized bed where the feed reacts with substantially only the hydrogen at a temperature of at least 900° F. The reaction products include synthetic crude oil and spent solids which are discharged from the fluidized bed reactor.
REFERENCES:
patent: 3001652 (1961-09-01), Schroeder et al.
patent: 3030297 (1962-04-01), Schroeder
patent: 3093420 (1963-06-01), Levene et al.
patent: 3762773 (1973-10-01), Schroeder
patent: 4075081 (1978-02-01), Gregoli
patent: 4094767 (1978-06-01), Gifford
patent: 4206032 (1980-06-01), Friedman et al.
patent: 6139722 (2000-10-01), Kirkbride et al.
Doyle James A.
Hildebrandt Fred
Jr.
Kirkbride Chalmer G.
Chattanooga Corporation
Griffin Walter D.
Jr.
Morgan & Finnegan , LLP
Nguyen Tam M.
LandOfFree
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