WO2012058228A2 - Procédé de réduction des mercaptans dans les hydrocarbures - Google Patents

Procédé de réduction des mercaptans dans les hydrocarbures Download PDF

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Publication number
WO2012058228A2
WO2012058228A2 PCT/US2011/057722 US2011057722W WO2012058228A2 WO 2012058228 A2 WO2012058228 A2 WO 2012058228A2 US 2011057722 W US2011057722 W US 2011057722W WO 2012058228 A2 WO2012058228 A2 WO 2012058228A2
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WO
WIPO (PCT)
Prior art keywords
crude oil
solution
hypochlorite
spent
treatment solution
Prior art date
Application number
PCT/US2011/057722
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English (en)
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WO2012058228A3 (fr
Inventor
Lin Li
Zunqing He
Zhen Zhou
King T. Ng
Paul E. Hajdu
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Chevron U.S.A. Inc.
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Publication date
Application filed by Chevron U.S.A. Inc. filed Critical Chevron U.S.A. Inc.
Priority to RU2013124378A priority Critical patent/RU2617415C2/ru
Priority to SG2013029749A priority patent/SG189940A1/en
Publication of WO2012058228A2 publication Critical patent/WO2012058228A2/fr
Publication of WO2012058228A3 publication Critical patent/WO2012058228A3/fr

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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
    • C10G27/00—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation
    • C10G27/04—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation with oxygen or compounds generating oxygen
    • C10G27/06—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation with oxygen or compounds generating oxygen in the presence of alkaline solutions
    • 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
    • C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
    • C10G2300/10—Feedstock materials
    • C10G2300/1033—Oil well production fluids
    • 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
    • C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
    • C10G2300/20—Characteristics of the feedstock or the products
    • C10G2300/201—Impurities
    • C10G2300/202—Heteroatoms content, i.e. S, N, O, P
    • 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
    • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
    • C10G2400/08—Jet fuel
    • 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
    • C10G27/00—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation
    • C10G27/02—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation with halogen or compounds generating halogen; Hypochlorous acid or salts thereof
    • 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

Definitions

  • the invention relates generally to methods for reducing mercaptan
  • hydrocarbons such as crude oil and jet fuel
  • mercaptans which may have an impact on the value of these hydrocarbon streams.
  • hydrocarbon streams are usually sold at a discount in the market or have to be upgraded to meet product spec.
  • reducing the mercaptan content could substantially improve both the marketability and the value of such hydrocarbons.
  • the treated crude product may not be suitable for downstream processing with a high inorganic content in the treated crude. Additionally, transportation of fresh bulk chlorine to distant sites for crude treatment (as well as the removal of waste chlorine after treatment) is a major safety concern since the transport of chlorine gas under high pressure can be very hazardous. The transportation of commercial hypochlorite, which is predominantly water, is very expensive due to stringent regulations to prevent accidental releases. [006] There is still a need for an improved and effective process for the removal of sulfur containing compounds such as mercaptans from crudes. There is further a need for an integrated system for the removal of mercaptans with minimal chlorite to waste treatment.
  • the invention relates to a method for reducing mercaptan concentration in a liquid hydrocarbon, comprising: contacting a mercaptan-rich liquid hydrocarbon having a first concentration of mercaptan sulfur with a composition comprising an oxidizing agent and water wherein the molar ratio of the oxidizing agent to mercaptan sulfur in the mercaptan-rich liquid hydrocarbon is from 3: 1 to 10: 1; and separating the water from the liquid hydrocarbon to yield a mercaptan-depleted liquid hydrocarbon having a second concentration of mercaptan sulfur, the second concentration being less than the first concentration; wherein a major amount of mercaptan compounds in the mercaptan-rich liquid hydrocarbon are converted to at least one sulfur oxoacid or salt having the formula [RSO x ] n Y wherein R is a hydrocarbyl group; x is an integer from 1 to 3; n is 1 or 2; and Y is hydrogen, an
  • the invention in another aspect, relates to a method for treating a crude oil containing mercaptans.
  • the method comprises contacting a crude oil feed with a treatment solution comprising a hypochlorite wherein the molar ratio of hypochlorite to mercaptan sulfur in the liquid hydrocarbon ranges from 1 : 1 to 10: 1, whereby the hypochlorite oxidizes the mercaptans generating a treated crude oil having a reduced concentration of mercaptans of less than 50 ppm and a first concentration of chloride and a spent treatment solution containing at least a sulfur oxoacid or salt thereof, having the formula [RSO x ] n Y, wherein R is a hydrocarbyl group; x is an integer from 1 to 3; n is 1 or 2; and Y is hydrogen, an alkaline metal, or alkaline earth metal; recovering the spent treatment solution and the treated crude oil; contacting the treated crude oil with a caustic solution at a
  • the invention relates to a closed-loop process to reduce mercaptan sulfur in a crude oil feed.
  • the process comprises: combining a sodium hypochlorite solution with a least a base to form a treatment solution having a pre-select pH; contacting the crude oil feed with the treatment solution comprising the sodium hypochlorite at a pre-select pH under intimate contact conditions sufficient for the hypochlorite to oxidize the mercaptans generating a treated crude oil having a reduced concentration of mercaptans of less than 50 ppm and a first concentration of chloride and a spent treatment solution;
  • Figure 1 provides an overview of an embodiment of a process for removing mercaptan sulfur from a crude oil, wherein the spent treatment solution is recycled.
  • Liquid hydrocarbon refers to all types of hydrocarbon fluids including but not limited to oils obtained from wells, shale, rock and/or sand among others, oil field condensates (e.g., natural gas liquid, etc.), residual oil, petroleum distillates (e.g., gasoline, jet fuel, kerosene, diesel, aromatics, etc.), paraffmic solvents (e.g., pentane, heptane, etc.), renewable fuels such as biodiesel, and mixtures thereof.
  • Liquid hydrocarbon may contain oxygenated compounds, such as alcohols, esters, glycols, ethers, and mixtures thereof.
  • the term “crude” or “crude oil” may be used interchangeably with “liquid hydrocarbon.”
  • the term “crude” or “crude blend” is used interchangeably and each is intended to include both a single crude and blends of crudes.
  • Jet fuel refers to hydrocarbons having a boiling range between 280°F and 572°F (138°C and 300°C).
  • Mercaptan refers to compounds of the general formula R-SH wherein “R” means a hydrocarbyl group and “SH” means a mercaptan group. It is understood that hydrogen sulfide (H 2 S) may also be removed (treated) along with mercaptan in the process and system of the invention.
  • “Sweeten” or “sweetening” refers to the process step or steps to remove sulfur and sulfur compounds including mercaptans from crude oil.
  • Hydrocarbyl refers to hydrocarbyl radicals containing 1 to 48 carbon atoms including branched or unbranched, cyclic or acyclic, saturated or unsaturated species, such as alkyl groups, alkenyl groups, or aryl groups.
  • Mercaptan-rich liquid hydrocarbon refers to a liquid hydrocarbon having a mercaptan sulfur content of at least 200 ppm.
  • the invention effectively reduces the level of mercaptan sulfur in a liquid hydrocarbon with the use of a hypochlorite solution as an oxidant.
  • the process is a closed-loop process wherein spent hypochlorite is recycled and regenerated for the oxidizing reaction.
  • Liquid Hydrocarbon for Treatment The concentration of mercaptan sulfur in a liquid hydrocarbon is dependent on the source.
  • the liquid hydrocarbon contains at least 200 ppm mercaptan sulfur; in a second embodiment, at least 300 ppm mercaptan sulfur; in a third embodiment, at least 400 ppm mercaptan sulfur; in a fourth embodiment, at least 500 ppm mercaptan sulfur; in a fifth embodiment, at least 600 ppm mercaptan sulfur; in a sixth embodiment, no more than 3000 ppm mercaptan sulfur.
  • the additive composition for the removal of mercaptans comprises at least a hypochlorite salt, which is soluble in water or in a water and low molecular weight alkanol mixture. Typical low molecular weight alkanols include methanol and ethanol.
  • the additive is employed in a molar ratio of 1 : 1 to 12: 1 hypochlorite (CIO " ) to mercaptan sulfur (RSH) in the liquid hydrocarbon to be treated.
  • CIO " hypochlorite
  • RSH mercaptan sulfur
  • the oxidized mercaptan is in the form of sulfur oxoacid or salt thereof, having the formula [RSO x ] n Y, wherein R is a hydrocarbyl group; x is an integer from 1 to 3; n is 1 or 2; and Y is hydrogen, an alkaline metal, or alkaline earth metal.
  • Sulfur oxoacid (and salt) is highly water soluble and therefore easily removed from the hydrocarbon stream.
  • the hypochlorite additive is an alkali or alkaline earth metal hypochlorite salt, e.g., sodium hypochlorite, potassium hypochlorite, calcium hypochlorite, and magnesium hypochlorite.
  • the additive is sodium hypochlorite.
  • Aqueous sodium hypochlorite solutions are widely available in varying concentration ranges, from 1 wt. % to saturation. In one embodiment, the concentration ranges from 1-15 wt. %.
  • the pH of the additive composition may be adjusted to a pre-select pH prior to being brought into contact with the liquid hydrocarbon for treatment by adding a suitable base selected from alkali metal hydroxides, alkaline earth metal hydroxides, and mixtures thereof.
  • a suitable base selected from alkali metal hydroxides, alkaline earth metal hydroxides, and mixtures thereof.
  • the pre-select pH ranges from 7 to 14 in one embodiment, from 8-12 in a second embodiment; from 8-10 in a third embodiment.
  • hydrocarbon having a first concentration of mercaptan sulfur is "sweetened" upon contact with the additive composition by means known in the art, followed by separating the water from the liquid hydrocarbon to yield a mercaptan-depleted liquid hydrocarbon having a second concentration of mercaptan sulfur, the second concentration being less than the first concentration.
  • the contact can be from 20°C to 300°C; in a second embodiment, from 20°C to 100°C: in a third embodiment, at room temperature.
  • the amount of the hypochlorite composition to the mercaptan-rich crude ranges from 5:95 to 95:5 volumetric ratio in one embodiment; from 1 :5 to 5: 1 in a second embodiment; from 1 :4 to 3: 1 in a third embodiment.
  • the volumetric ratio of hypochlorite to crude varies depending on a number of factors, including the concentration of hypochlorite solution and the amount / type of the sulfur compounds in the crude.
  • At least 60 percent by weight of the mercaptan compounds in the mercaptan-rich liquid hydrocarbon are converted to the at least one sulfur oxoacid or salt thereof; in a another embodiment, at least 70 percent by weight of the mercaptan compounds in the mercaptan-rich liquid hydrocarbon are converted to the at least one sulfur oxoacid or salt thereof; in yet another embodiment, at least 80 percent by weight of the mercaptan compounds in the mercaptan-rich liquid hydrocarbon are converted to the at least one sulfur oxoacid or salt thereof.
  • the treated crude contains less than 50 ppm mercaptan sulfur; in a second embodiment, less than 40 ppm mercaptan sulfur; in a third embodiment, less than 30 ppm mercaptan sulfur; in a fourth embodiment, less than 20 ppm mercaptan sulfur; in a fifth embodiment, less than 10 ppm mercaptan sulfur; in a sixth embodiment, less than 5 ppm mercaptan sulfur; in a seventh embodiment, less than 1 ppm mercaptan sulfur.
  • the contact is for a sufficient time such that a major amount of mercaptan compounds in the mercaptan-rich liquid hydrocarbon are converted to at least one sulfur oxoacid or salt.
  • the contact time is at least 30 seconds; in a second embodiment, at least one minute; in a third embodiment, at least five minutes; in a fourth embodiment, at least one hour; in a fifth embodiment, at least two hours; in a sixth embodiment, less than 24 hours.
  • the hypochlorite composition can be introduced continuously or intermittently into operating pipelines containing the crude. Alternatively, batch introduction can be used for offline pipelines or equipment. In yet another
  • crude oil is injected on a continuous or intermittent basis into the hypochlorite solution for maximum contact.
  • phase separation devices include, but are not limited to, cyclone devices, electrostatic coalescent devices, gravitational oil-water separators, and centrifugal separators.
  • the mercaptan-rich crude oil before sweetening with hypochlorite, is optionally brought into contact with a caustic solution at a crude to caustic solution volume ratio ranging from 5: 1 to 1 : 10, and caustic concentration ranging from 1-5 wt. %.
  • the process further includes a second and subsequent mercaptan extraction step with the hypochlorite solution, or other oxidants, to further reduce mercaptan content as well as other sulfur compounds that are difficult to oxidize.
  • a final extraction step with ionic liquid may be included.
  • substitution of the hypochlorite solution with ionic liquid for one of the extraction steps may be conducted.
  • the mercaptan-rich crude oil is optionally brought into contact with an oxygen containing gas stream, such as air, before contacting the hypochlorite solution, to accelerate the oxidation reaction.
  • an oxygen containing gas stream such as air
  • the contacting between the crude oil and the hypochlorite solution can be either via non-dispersive or dispersive methods.
  • the non-dispersive method can be via either packed inert particle beds or fiber film contactors.
  • the dispersive contacting method can be via any of mixing valves, static mixers and mixing tanks or vessels.
  • the treatment step is carried out in a unit operation with two separate zones, a contact zone and a separation zone.
  • the contact zone is for the contact between the hypochlorite and the crude oil, which can be in any form of packed tower, bubble tray, stirred mixing tank, fiber contacting, rotating disc contactor or other contacting devices known in the art.
  • the liquid-liquid contact is via fiber contacting, which is also called mass transfer contacting, wherein large surface areas are provided for mass transfer in a non-dispersive manner as described in US Patent Nos.
  • the separation zone can be at least a separation device selected from any of settling tanks or drums, coalescers, electrostatic precipitators, and other similar devices.
  • the treatment is via an integrated unit, e.g., a single vessel having a contact zone for mercaptan-rich crude to be in intimate contact with the hypochlorite solution (and / or optional additives and alternative treatment additives), and a settling zone for the separation of the treated crude from the spent hypochlorite solution.
  • Hypochlorite solution can be mixed with the crude oil prior to entering the contact zone, or injected as a separate stream into the contacting zone.
  • the flow of the hypochlorite solution and the crude oil in the unit can be counter-current or con-current.
  • the treatment is via a single tower with a top section for the oxidizing with hypochlorite and a bottom section for the separation of the treated crude from the spent hypochlorite solution.
  • the top section comprises at least a contactor characterized by large surface areas, e.g., a plurality of fibers or bundles of fibers, allowing mass transfer in a non-dispersive manner.
  • the fibers for use in the contactors are constructed from materials consisting of but not limited to metals, glass, polymers, graphite, and carbon, which allow for the wetting of the fibers and which do not contaminate the process or be quickly corroded in the process.
  • the fibers can be porous or non-porous, or a mixture of both.
  • the oxidizing section contains at least two contactors comprising fibers in series.
  • the fibers in each contactor are wetted by the hypochlorite solution to form a thin film on the surface of fibers, and present a large surface area to the crude oil to be treated by the oxidizing of mercaptans by the hypochlorite solution.
  • the admixture of the treated crude oil and spent hypochlorite solution exits the bottom of the first contactor and flows into the next contactor in series, then exiting the bottom contactor and is directed to a bottom separation section.
  • additional fresh hypochlorite solution is provided to the second contactor for the additional treatment of the crude.
  • spent hypochlorite solution from the separation zone is recycled back to the oxidizing section for treatment of the crude.
  • the treated crude is allowed to separate from the spent hypochlorite via gravity settling.
  • the bottom section also comprises fibers to aid with the separation, wherein the mixture of treated crude oil and spent hypochlorite solution flows through the fibers to form two distinct liquid layers, an upper layer of treated crude and a lower layer of spent hypochlorite solution.
  • the sweetening step is carried out in an integrated unit having multiple sections, e.g., an extractor section for converting mercaptans to RSO 3 H upon contact with hypochlorite; a pre -mixing section for adjusting the hypochlorite to a preselect pH with the addition with an alkali such as caustic, with the pre-mixing section in direction communication with the extractor section; and a coalescer / separation section in communication with the extractor section for the separation of treated crude from the spent hypochlorite.
  • an extractor section for converting mercaptans to RSO 3 H upon contact with hypochlorite
  • a pre -mixing section for adjusting the hypochlorite to a preselect pH with the addition with an alkali such as caustic, with the pre-mixing section in direction communication with the extractor section
  • a coalescer / separation section in communication with the extractor section for the separation of treated crude from the spent hypochlorite.
  • an interface control structure is employed for sensing the interface level between the treated crude and the spent hypochlorite solution.
  • the interface control structure is adjusted to optimally alter the vertical height of the interface level within the equipment, and / or the flows of the various inlet and outlet streams to the equipment for optimal mercaptan removal.
  • the treated crude after the sweetening step, has a residual organic halide impurity content, typically from about 40 to 4000 ppm. The presence of organic halides in such treated products may be undesirable.
  • the treated crude undergoes a desalting step, e.g., being brought in contact with an aqueous caustic solution under conditions to generate an upgraded crude with a reduced halide concentration.
  • the aqueous caustic solution is selected from alkali and alkaline earth metal hydroxide solutions, and mixtures thereof. Examples include lithium hydroxide, sodium hydroxide, sodium carbonate, potassium hydroxide, calcium hydroxide, and magnesium hydroxide solutions.
  • the aqueous caustic solution is a sodium hydroxide solution.
  • the concentration of caustic ranges from 0.001 N to 10 N.
  • the caustic concentration ranges from 0.5 N to 5N.
  • the caustic stream comprises aqueous sodium hydroxide at a concentration ranging from about 2 to about 30 mol %.
  • the molar ratio of caustic to halogen-containing oxidizing agent e.g., chloride
  • the amount of aqueous caustic solution to the mercaptan-depleted liquid hydrocarbon is from 5:95 to 95:5 volumetric from which halide is removed.
  • the upgraded crude with a reduced halide concentration contains less than 10 ppm organic chloride in one embodiment; less than 5 ppm in a second embodiment; less than 2 ppm in a third embodiment; and less than 1 ppm in a fifth embodiment.
  • the upgraded crude may be further processed by hydrotreating, for example.
  • the mercaptan-depleted crude is contacted with an aqueous caustic solution by means known in the art. Methods may be conducted as batch, semi-continuous or continuous processes (as in the treatment with hypochlorite solution).
  • the contact is from 20°C to 300°C; in a second embodiment, from 25°C to 200°C; in a third embodiment, from 30°C to 150°C; in a fourth embodiment, from 70°C to 100°C. Contact may be done with vigorous mixing.
  • the contact time is at least one minute; in another embodiment, at least five minutes; in yet another embodiment, at least one hour; in still yet another embodiment, at least two hours; in one embodiment, less than 24 hours.
  • the aqueous caustic solution further comprises chemical desalters / demulsifiers known in the art.
  • a low molecular weight alkanol is employed as a co-solvent.
  • the low molecular weight alkanol may have straight or branched chain alkyl groups containing 1 to 4 carbon atoms.
  • suitable alkanols include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol and tert-butanol and mixtures thereof.
  • the low molecular weight alkanol is ethanol.
  • the amount of lower alkanol is from 1-49 percent by weight based on the total weight of the solution; in another embodiment, from 5-25 percent by weight based on the total weight of the solution.
  • water soluble demulsifiers including but not limited to silicone polyethers, sulphonates, polyglycol ethers and mixtures thereof are employed in the range of 1 to 500 ppm.
  • the aqueous caustic solution further comprises a phase transfer catalyst.
  • suitable phase transfer catalysts include, but are not limited to, quaternary ammonium salts, phosphonium salts and pyridinium salts.
  • the phase transfer catalyst may be present in an amount from 0.001 to 0.5 mole equivalents of caustic agent.
  • the phase transfer catalyst is a quaternary salt.
  • the phase transfer catalyst is cetyltrimethylammonium chloride.
  • the mercaptan-depleted upgraded crude is recovered resulting in a mercaptan-depleted liquid hydrocarbon with a reduced halide concentration.
  • Any means of separating the aqueous caustic solution from the mercaptan- depleted upgraded crude may be used. Examples include decantation, gravity separation, settler based on gravity, extractor, membrane separator, fibrous coalescer as disclosed in US Patent Nos. 4640781 and 5017294, and other devices that are known in the art, the relevant disclosures are included herein by reference.
  • recovered or spent caustic solution can be routed and combined with spent chlorite solution for subsequent recycled / regeneration generating hypochlorite as feed for the removal of mercaptans.
  • spent caustic solution is treated via commercially treatment processes to remove undesirable impurities such as sodium sulfide, sodium mercaptide, etc., which can cause high COD and BOD in the waste water treatment plant.
  • the spent caustic solution is treated to remove residual sulfur compounds prior to recycling according to US Patent Publication No. 20090065434, the relevant disclosures are included herein by reference.
  • the spent caustic solution after treatment is routed to the crude unit or sour water stripper.
  • hypochlorite is recycled / regenerated so that fresh hypochlorite is not needed.
  • a small amount of hypochlorite may be needed for start-up or as back-up for electrolyzer.
  • a make-up brine solution is needed to account for losses of brine solution in the system. In one embodiment, this stream accounts for less than 30% of the brine solution needed to generate the
  • hypochlorite for mercaptan removal is made.
  • the make-up brine accounts for 5 to 50% of the total brine solution needed to generate the hypochlorite needed for mercaptan removal.
  • the caustic treatment can be accomplished by any liquid-liquid mixing device, such as packed tower, bubble tray, stirred vessel, fiber contacting, rotating disc contactor, plug flow reactor, etc.
  • the caustic treatment is performed using equipment substantially the same as for the sweetening process, e.g., a vessel with multiple zones, or a vessel comprising at least a contactor comprising substantially continuous elongated fibers, wherein the fibers are wetted by the caustic solution and present a large surface area to the crude to be desalted.
  • two or more stages of contacting with an aqueous treatment solution may be adopted to achieve a greater extent of treating efficiency.
  • contactors employing fibers are employed for the phase separation of the spent caustic and the mercaptan-depleted upgraded crude product.
  • spent hypochlorite solution recovered from the sweetening step contains unexpended hypochlorite, sodium chloride NaCl, various products of the reaction treatment including sulfoxides and sulfonate species formed from mercaptan oxidation as well as other impurities.
  • the spent solution further includes caustic soda.
  • as much NaCl and water are recovered from the spent treatment solution as possible.
  • sulfoxides species, sulfonate species and other non-chloride impurities are extracted (removed) from the spent treatment solution for the brine solution to meet the impurity specification of the electrolyzer unit for use in regenerating hypochlorite.
  • impurities sulfoxides species, sulfonate species and other non-chloride impurities
  • at least 95% of the impurities are removed.
  • at least 99% of the impurities are removed.
  • a brine solution containing less than 0.5 wt. % in impurities is recycled to an electrolyzer for NaCIO regeneration.
  • impurities are removed using carbon adsorption and / or a water softener unit, e.g., a ion exchange unit employing an anion exchange resin.
  • a water softener unit e.g., a ion exchange unit employing an anion exchange resin.
  • cross-flow microfiltration and / or nanofiltration equipment is used separately or in combination with carbon adsorption / carbon filtration for the removal of impurities from the brine solution.
  • recovered brine solution is regenerated to generate hypochlorite for use in the treatment solution.
  • the system in one embodiment comprises an electrolyzer assembly having at least an electrolyzer cell. Details regarding the description of equipment and the electrolyzing step to generate hypochlorite are described in US Patent Nos. 6235167, 6805787, and 7931795, the relevant disclosures are included herein by reference.
  • the regenerated hypochlorite is routed to the sweetening unit as a feed stream for use in the removal of mercaptans.
  • the brine solution prior to electrolyzing, is first concentrated for optimal performance in the electrolyzer with maximum efficiency.
  • the removal of water is done via means known in the art, for the brine solution to meet the specification of the electrolyzer. At least 20% of the water is removed in a reverse osmosis (RO) step in one embodiment; at least 50% in a second embodiment; and at least 90% in a third embodiment.
  • RO reverse osmosis
  • a system with multiple modules includes: a) a brine softener unit with chelating ion exchange resins for the removal of impurities from the spent hypochlorite generating a brine solution; b) an electrolyzer unit for the production of chlorine gas and a sodium hydroxide co-product from the brine solution; and c) a hypochlorite conversion unit where elemental chlorine gas reacts with sodium hydroxide solution to produce sodium hypochlorite at the desired concentration.
  • the system further includes a RO unit for the concentration of the brine solution.
  • unit 2 can be a similar or different from unit 1 in terms of design.
  • unit 2 is also an integrated unit including a desalter / coalescer, reducing water and inorganic salt content of the treated product, generating a final product oil 22 which can be sent to storage, and spent caustic stream 23 for recycle / re-use.
  • the spent hypochlorite stream 12 is combined with the spent water treatment / caustic stream 23 into a combined stream 31.
  • This stream contains sodium chloride, sulfonate species formed from mercaptan oxidation by hypochlorite, as well as other impurities.
  • the spent stream 31 is purified in filtration unit 3 to remove sulfonate species and other impurities.
  • the purified stream 32 is sent to RO unit 4 to be concentrated, generating a fresh water stream 41 and a concentrated brine solution 42 for the electrolyzer unit 5.
  • a make-up brine stream 51 is provided to maintain an adequate hypochlorite to mercaptan ratio for the sweetening reaction.
  • Sufficient amount of water 43 is provided to the closed loop and combined with fresh water stream 41, generating enough water to dilute the hypochlorite stream 52 to the desired concentration, constituting hypochlorite solution 53 feed to the system.
  • XPS X-ray photoelectron spectroscopy
  • Examples 13-16 A halide-containing liquid hydrocarbon was prepared by treating a high mercaptan sulfur crude oil blend with a 1% aqueous sodium hypochlorite solution (6:1 NaC10:RSH molar ratio) for 5 minutes at room temperature with vigorous stirring. The layers were allowed to separate. The crude oil treated with the halide-containing oxidizing agent was collected and then washed with an aqueous caustic solution. The organic chloride content in the washed oil was determined according to ASTM D4929. The chloride reduction results are set forth in Table 5, showing that aqueous caustic solutions are effective in reducing the organic chloride content of a crude oil treated with the halide-containing oxidizing agent using the disclosed method.
  • Example 17-21 Model samples were prepared adding a sufficient amount of thiophenol in toluene for a sulfur concentration of 600ppm. The mixing was carried out in two modes: A) NaCIO was stirred mixed in toluene solution at room temperature for 60 minutes; or B) toluene was injected into the NaCIO solution while it was being stirred mixed.

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

Abstract

Cette invention concerne un procédé de réduction de la concentration en mercaptans dans du pétrole brut. Le procédé consiste à mettre en contact le pétrole brut avec une solution de traitement constituée d'une solution d'hypochlorite, le soufre des mercaptans étant oxydé et converti en au moins un oxoacide de soufre ou un sel de ce dernier, ce qui produit un pétrole brut traité contenant moins de 50 ppm de soufre de mercaptan et de chlore résiduel. Le pétrole brut traité contenant le résidu de chlore est amené au contact d'une solution caustique en un rapport molaire solution caustique/chlore allant de 0,05:1 à 1:1, ce qui génère un pétrole brut affiné contenant moins de 50 ppm de chlore. Dans un mode de réalisation, la solution de traitement usitée est recyclée pour former un courant d'hypochlorite régénéré qui est utilisé dans la solution de traitement.
PCT/US2011/057722 2010-10-28 2011-10-25 Procédé de réduction des mercaptans dans les hydrocarbures WO2012058228A2 (fr)

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RU2013124378A RU2617415C2 (ru) 2010-10-28 2011-10-25 Способ снижения содержания меркаптанов в углеводородах
SG2013029749A SG189940A1 (en) 2010-10-28 2011-10-25 Method for reducing mercaptans in hydrocarbons

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US12/914,275 US20120103871A1 (en) 2010-10-28 2010-10-28 Method for Reducing Mercaptans in Hydrocarbons

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US4816139A (en) * 1986-06-27 1989-03-28 Tenneco Oil Company Method for removing sulfur compounds from C6 and lower alkanes
JPH091191A (ja) * 1995-06-19 1997-01-07 Ebara Corp 消臭方法
US20070227950A1 (en) * 2003-12-24 2007-10-04 Martinie Gary D Reactive Extraction of Sulfur Compounds from Hydrocarbon Streams

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US2903422A (en) * 1955-08-10 1959-09-08 Shell Dev Process for sweetening hydrocarbons with alkali hypochlorites, alkali hydroxides and alkali mercaptides
JPS5594625A (en) * 1979-01-16 1980-07-18 Fuso:Kk Deodorizing method for malodorous gas containing methyl mercaptan and methyl sulfide
US5093011A (en) * 1990-12-12 1992-03-03 Chemical Waste Management, Inc. Process for dehalogenation of contaminated waste materials
RU2087520C1 (ru) * 1994-09-21 1997-08-20 Всероссийский научно-исследовательский институт углеводородного сырья Способ очистки нефти, нефтепродуктов и газоконденсата от меркаптанов
US6015536A (en) * 1998-01-14 2000-01-18 Ecolab Inc. Peroxyacid compound use in odor reduction
US6402940B1 (en) * 2000-09-01 2002-06-11 Unipure Corporation Process for removing low amounts of organic sulfur from hydrocarbon fuels
US20050218038A1 (en) * 2004-03-31 2005-10-06 Nero Vincent P Pre-treatment of hydrocarbon feed prior to oxidative desulfurization

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4120779A (en) * 1975-04-28 1978-10-17 Exxon Research & Engineering Co. Process for desulfurization of residua with sodamide-hydrogen and regeneration of sodamide
US4816139A (en) * 1986-06-27 1989-03-28 Tenneco Oil Company Method for removing sulfur compounds from C6 and lower alkanes
JPH091191A (ja) * 1995-06-19 1997-01-07 Ebara Corp 消臭方法
US20070227950A1 (en) * 2003-12-24 2007-10-04 Martinie Gary D Reactive Extraction of Sulfur Compounds from Hydrocarbon Streams

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WO2012058228A3 (fr) 2012-08-16
RU2013124378A (ru) 2014-12-10
WO2012057935A3 (fr) 2012-06-14
SG189940A1 (en) 2013-06-28
US20120103871A1 (en) 2012-05-03
WO2012057935A2 (fr) 2012-05-03
RU2617415C2 (ru) 2017-04-25

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