Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G33/00—Dewatering or demulsification of hydrocarbon oils
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/02—Separation of non-miscible liquids
  • B01D17/04—Breaking emulsions
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/02—Separation of non-miscible liquids
  • B01D17/04—Breaking emulsions
  • B01D17/042—Breaking emulsions by changing the temperature
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/02—Separation of non-miscible liquids
  • B01D17/04—Breaking emulsions
  • B01D17/044—Breaking emulsions by changing the pressure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/06—Separation of liquids from each other by electricity
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G33/00—Dewatering or demulsification of hydrocarbon oils
  • C10G33/04—Dewatering or demulsification of hydrocarbon oils with chemical means

Definitions

• This invention relates to systems and methods used in crude oil production. More specifically, the invention relates to methods for treating the rag mixture that accumulates at the oil/water interface inside of separation, dehydration and desalting equipment.
• bitumen In the production of heavy crude oils such as bitumen, which typically have an API gravity less than 10, light diluents are used to adjust the API gravity to above 15 API.
• the combination of diluent and bitumen is commonly referred to as "dilbit.”
• Bitumen is produced from subterranean formations by a wide variety of production methods such as steam injection, propane injection, and hot water injection. After the bitumen is produced, it is blended with the diluent to increase the API gravity to about 15 to 17 API. Once the API is above 12 API, conventional oilfield equipment can be utilized.
• This equipment routinely consists of a free water knockout or FWKO, a 2-phase or 3-phase gravity separator, a mechanical or electrostatic oil dehydrator (treater) and, in some cases, an electrostatic desalter.
• the quality of 15 API dilbit is very poor.
• These blends typically contain high levels of solids from the subterranean formation and large quantities of asphaltenes formed by the additional diluents.
• the solids and asphaltenes permit the formation of a mixture of dilbit, water, solids and asphaltenes, which routinely accumulate at the oil/water interface inside of separation, dehydration and desalting equipment. This mixture is commonly referred to as "rag.”
• the volume of rag produced can range from a small volume to several percent of the production stream. Typically, the rag produced is about 1 to 3% of the volume of the produced oil. For example, a Canadian producer might handle 50,000 bpd of bitumen and produce about 500 bpd (barrels per day) of rag.
• rag may be processed in a flash treater that heats the rag to a temperature above 250 0 F and then flashes it to remove the water. Flash treaters, such as those used on Canadian dilbit, leave all the solids, asphaltenes and production salts in the dilbit. These undesirable constituents must then be processed by the refinery. Many refiners have begun to penalize producers for selling flash treated oil. A need exists for an improved method of treating interface rag.
• a method for treating an interface rag includes the step of removing a volume of rag at a controlled rate from at least one upstream separator vessel equipped with a rag drain.
• the rag is then passed through a pump that provides sufficient pressure to pass the rag to a heater but prevent boiling the water content of the rag and vaporizing the light hydrocarbon content of the rag.
• the rag is then heated to a first temperature effective for thermally decomposing any chemical previously added to the interface rag to promote separation of the rag.
• a first temperature of at least 35O 0 F has proved effective.
• Additional diluent is mixed with the heated rag to produce a rag having an API gravity of 30.
• the diluent also cools the 30 API rag to a second temperature of about 300° F.
• the cooled diluted rag is then passed to a separator device.
• the separator device may be an electrostatic treater or a hydrocyclone cluster.
• the electrostatic treater is preferably a vertical electrostatic treater having a conical-shaped lower portion.
• the water below the oil/water interface may be recycled within the treater.
• the water level may also be monitored.
• the solid-laden water is then extracted from the treater and passed to one or more hydrocyclones. The underflow and overflow of the hydrocyclone (or the hydrocyclone cluster) is collected.
• Figure 1 illustrates a process flow for treating a dilbit interface rag that employs an electrostatic treater and a hydrocyclone cluster to produce a saleable oil.
• Figure 2 illustrates a process flow for treating a dilbit interface rag that eliminates the electrostatic treater and instead employs the hydrocyclone cluster alone.
• method 10 may be applied to any process involving a heavy crude oil and a diluent, such as in refinery processes.
• Method 10 for continuous processing and treatment of dilbit interface rag is illustrated that eliminates the need for tank storage and a flash treater and produces a saleable product to a refiner.
• Method 10 requires rag sources 20 — such as a free water knockout, a 2-phase or 3 -phase gravity separator, a mechanical or electrostatic oil dehydrator or, in some cases, an electrostatic desalter (indicated by rag streams 22, 24, 26, & 28, respectively) — to be equipped with rag drains or other means that permit the continuous and controlled removal of interface rag from the rag sources 20.
• One or more of the rag streams 22, 24, 26 & 28 make up the extracted rag stream 30 for further processing by method 10.
• Extracted rag stream 30 is transferred by a high pressure pump 32 into a heater 36. Pump
• the pressurized rag stream 34 is then heated in heater 36 to a temperature that provides for resolution of the rag stream 34. For the most effective rag resolution, the temperature must be increased to over 350 0 F. At temperatures over 350 0 F, any chemicals that have been added to the bitumen and dilbit to promote separation are thermally decomposed and can no longer stabilize the heated rag stream 38.
• Additional diluent 40 is added to the heated rag stream 38 and mixed in a mixer 38.
• Diluent 40 serves to cool the heated rag 38 to a temperature about 300 0 F and increase the API to an API gravity of about 30.
• the cooled diluted rag stream 44 is then routed to an inlet 56 of an electrostatic treater 50. Alternatively, it may be routed directly to a hydrocyclone cluster 90 (see Figure 2).
• Electrostatic treater 50 includes electrodes 58 — located in an upper portion 52 of treater 50 and in communication with a power source 78 — that form an electric field within an interior of treater 50.
• the diluted rag 44 will not be able to suspend the water and solids.
• the water/solids 64 therefore, readily separate out of the rag 44 and flow to the bottom end 70 of treater 50.
• the oil 60 separates and flows upward to a top outlet 62. Because the rag 44 is likely to contain a high concentration of solids, it is not practical to permit the solids to settle to the bottom end 70 of treater 50 for periodic removal. Rather the water below the oil- water interface 66 should be continuously agitated to keep the solids in suspension. To maintain agitation and scrub any excess bitumen from the solids, electrostatic treater
• the solid-laden water 64 may be monitored by a level-controller (not shown) and removed by a level-control valve (not shown) through bottom outlet 74.
• an alternative method 10 eliminates electrostatic treater 50 and processes diluted rag stream 44 in a hydrocyclone cluster 90.
• Figures 1 and 2 illustrate equipment that could be assembled as a portable unit that could be moved to various locations where rag exists or where rag has been stored.
• portable units capable of performing the methods and processes described and illustrated herein can be transported from site to site to provide rag treatment services.

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Engineering & Computer Science (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Peptides Or Proteins (AREA)

Priority Applications (6)

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Publications (1)

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Citations (5)

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• 2009
  • 2009-05-01 US US12/434,160 patent/US9023213B2/en active Active
• 2010
  • 2010-04-15 SG SG2011078292A patent/SG175791A1/en unknown
  • 2010-04-15 GB GB1118273.0A patent/GB2482443B/en not_active Expired - Fee Related
  • 2010-04-15 CA CA2760134A patent/CA2760134C/en not_active Expired - Fee Related
  • 2010-04-15 BR BRPI1007655A patent/BRPI1007655A2/pt not_active Application Discontinuation
  • 2010-04-15 JP JP2012508521A patent/JP2012525469A/ja active Pending
  • 2010-04-15 WO PCT/US2010/031215 patent/WO2010126717A1/en not_active Ceased
• 2011
  • 2011-11-03 NO NO20111503A patent/NO20111503A1/no not_active Application Discontinuation

Patent Citations (5)

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