Mineral oils: processes and products – Fractionation – Deasphalting
Reexamination Certificate
2000-08-22
2003-03-18
Griffin, Walter D. (Department: 1764)
Mineral oils: processes and products
Fractionation
Deasphalting
C208S040000, C208S044000, C208S045000, C208S086000, C208S087000
Reexamination Certificate
active
06533925
ABSTRACT:
BACKGROUND OF THE INVENTION
Conventionally, a solvent deasphalting (SDA) process is employed by an oil refinery for the purpose of extracting valuable components from a residual oil feedstock, which is a heavy hydrocarbon produced as a by-product of refining crude oil. The extracted components are fed back to the refinery wherein they are converted into valuable lighter fractions such as gasoline. Suitable residual oil feedstocks which may be used in a SDA process include, for example, atmospheric tower bottoms, vacuum tower bottoms, crude oil, topped crude oils, coal oil extract, shale oils, and oils recovered from tar sands.
In a typical SDA process, a light hydrocarbon solvent is added to the residual oil feed from a refinery and is processed in what can be termed as an asphaltene separator. Common solvents used are methane, ethane, propane, butane, isobutane, pentane, isopentane, neopentane, hexane, isohexane, heptane, their mono-olefinic counterparts thereof, and similar known solvents used in deasphalting, and mixtures thereof. Under elevated temperature and pressures, the mixture in the asphaltene separator separates into a plurality of liquid streams, typically, a substantially asphaltene-free stream of deasphalted oil (DAO), resins and solvent, and a mixture of asphaltene and solvent within which some DAO may be dissolved. The SDA process is a well-known petroleum process and is described in U.S. Pat. No. 3,968,023 to Yan, U.S. Pat. No. 4,017,383 to Beavon, U.S. Pat. No. 4,125,458 to Bushnell, all incorporated herein by reference, and numerous others.
Once the asphaltenes have been removed, the substantially asphaltene-free stream of DAO, resins and solvent is normally subjected to a solvent recovery system. The solvent recovery system of an SDA unit extracts a fraction of the solvent from the solvent rich DAO by boiling off the solvent, commonly using steam or hot oil from fired heaters. The vaporized solvent is then condensed and recycled back for use in the SDA unit.
Often it becomes beneficial to separate a resin product from the DAO/resin product stream. This is normally done before the solvent is removed from the DAO. “Resins” as used herein, means resins that have been separated and obtained from a SDA unit. Resins are denser or heavier than deasphalted oil, but lighter than the aforementioned asphaltenes. The resin product usually comprises more aromatic hydrocarbons with highly aliphatic substituted side chains, and can also comprise metals, such as nickel and vanadium. Generally, the resins comprise the material from which asphaltenes and DAO have been removed.
U.S. Pat. No. 3,775,292 to Watkins teaches a SDA process where feedstock is deasphalted using a solvent, and then the resin is removed using a selective solvent in a solvent extraction unit so as to provide solvent-lean resin concentrate and a de-resined second liquid phase. Neither solvent is recovered, as the resin and the DAO is further processed in a hydrocracking unit so as to produce lower boiling hydrocarbons.
U.S. Pat. No. 4,101,415 to Crowley and U.S. Pat. No. 4,686,028 to Ven Driesen et al. teach similar SDA processes where a feedstock is subjected to a solvent extraction step that removes both the asphaltenes and the resin, resulting in an asphaltene-free and resin-free DAO. The asphaltene/resin mixture removed from the feedstock is then subjected to a second solvent extraction step that separates the resins from the asphaltenes.
U.S. Pat. No. 4,239,616 to Gearhart teaches a SKA process where a heavy hydrocarbon material is mixed with a solvent and then subjected to a first separation zone at elevated temperature and pressure so as to effect a separation of the material into a first light phase comprising oils, resins, and solvent, and a first heavy phase comprising asphaltenes and some solvent. The first light phase is sent to a second separation zone where it is subjected to temperatures higher than those in the first separation zone so as to effect a separation of the of the first light phase into a second light phase comprising oil and solvent and a second heavy phase comprising resins and some solvent. The second light phase is then sent to a third separation zone where it is separated into a third light phase comprising solvent and a third heavy phase comprising oils.
A key element of the '616 process is that at least a portion of the first heavy phase is introduced into the upper portion of the second separation zone. This is done so as to contact the first heavy phase with the second light phase and remove at least a portion of any resinous bodies that may be entrained in the second light phase. It is also preferred that the first heavy phase is sufficiently heated prior to its introduction into the second separation zone so as to cause the formation of internal reflux within the upper portion of the second separation zone, thus assisting in resin removal from the second light phase.
U.S. Pat. No. 4,454,023 to Lutz teaches a process whereby a heavy viscous hydrocarbon feed is processed in a visbreaker unit and fed to a distillation unit for fractionation. The bottoms product of the distillation unit is then fed to a solvent extraction unit producing a heavy asphaltene fraction as well as one or more lighter fractions which contain a large percentage of resins or oils. At least a portion of the lighter fractions that contains resin is recycled back to the feed stream to the visbreaker so as to increase the conversion in the visbreaker.
U.S. Pat. No. 5,145,574 to Hedrick teaches a process separating a resin phase from a solvent solution containing a solvent, DAO, and resin. The solvent solution is introduced into a special heat-exchange apparatus and directed over at least a portion of a generally vertically positioned heat-exchange surface thereby heating the solvent solution to precipitate the resin phase. A solvent solution having a reduced resin content is then recovered, as well as a resin product.
A separate, deasphalted resin product makes a better feed for heavy hydrocarbon cracking units such as H-OIL™, delayed cokers, and visbreaker units. Resin-free DAO is also an improved feedstock for product cracking units such as hydrotreaters, hydrocrackers, and catalytic cracking units.
H-OIL™ is a proprietary ebullated bed process (co-owned by Hydrocarbon Research, Inc. and Texaco Development Corporation) for the catalytic hydrogenation of heavy vacuum residuum, or “resid,” and heavy oils to produce upgraded distillate petroleum products and an unconverted bottoms product particularly suited for blending to a low sulfur fuel oil. In the H-OIL™ process, a catalyst is contacted with hydrogen and a sulfur- and metal-containing hydrocarbon feedstock by means which insures that the catalyst is maintained at essentially isothermal conditions and exposed to a uniform quality of feed. This hydroprocessing process is particularly effective in achieving high levels of hydrodesulfurization with vacuum resid feedstocks. The H-OIL™ product is characterized as a liquid product of lower density and average boiling point, lower sulfur content, and lower content of metals.
High conversion is difficult at times because resid feedstocks typically contain high concentrations of metals such as nickel, iron and vanadium as well as high concentrations of nitrogen and sulfur. Many of these materials can even deactivate or poison catalysts. Poisoning of the catalyst often leads to the need for frequent catalyst additions or changeouts which impact unit availability and throughput. Resid conversion also is difficult because resid feedstocks contain a large asphaltene fraction that produces insoluble carbonaceous material when the feedstock is heated. Formation of these solids often results in feedstock or temperature operating limitations. Resin feedstocks are lower in metals content and asphaltenes, and are thus better feedstocks for the H-OIL™ process than resids.
The delayed coking process is an established petroleum refinery process which is used on very heavy low value resid feeds, such as vacuum r
Johnson Kay A.
Niccum Jacqueline G.
Penrose Clint F.
Wallace Paul S.
Griffin Walter D.
Howrey Simon et al.
Nguyen Tam M.
Reinisch Morris N.
Texaco Development Corporation
LandOfFree
Asphalt and resin production to integration of solvent... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Asphalt and resin production to integration of solvent..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Asphalt and resin production to integration of solvent... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3007947