Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B7/00—Halogens; Halogen acids
  • C01B7/13—Iodine; Hydrogen iodide
  • C01B7/14—Iodine
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B9/00—General methods of preparing halides
  • C01B9/06—Iodides
• • 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
  • C10G17/00—Refining of hydrocarbon oils in the absence of hydrogen, with acids, acid-forming compounds or acid-containing liquids, e.g. acid sludge
  • C10G17/02—Refining of hydrocarbon oils in the absence of hydrogen, with acids, acid-forming compounds or acid-containing liquids, e.g. acid sludge with acids or acid-containing liquids, e.g. acid sludge
  • C10G17/04—Liquid-liquid treatment forming two immiscible phases
  • C10G17/07—Liquid-liquid treatment forming two immiscible phases using halogen acids or oxyacids of halogen
• • 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
  • C10G21/00—Refining of hydrocarbon oils, in the absence of hydrogen, by extraction with selective solvents
  • C10G21/06—Refining of hydrocarbon oils, in the absence of hydrogen, by extraction with selective solvents characterised by the solvent used
• • 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
  • C10G29/00—Refining of hydrocarbon oils, in the absence of hydrogen, with other chemicals
  • C10G29/02—Non-metals
• • 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
  • C10G29/00—Refining of hydrocarbon oils, in the absence of hydrogen, with other chemicals
  • C10G29/06—Metal salts, or metal salts deposited on a carrier
  • C10G29/12—Halides
• • 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
  • C10G29/00—Refining of hydrocarbon oils, in the absence of hydrogen, with other chemicals
  • C10G29/20—Organic compounds not containing metal atoms
  • C10G29/26—Halogenated hydrocarbons
• • 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
• • 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
  • C10G2300/10—Feedstock materials
  • C10G2300/1037—Hydrocarbon fractions
  • C10G2300/104—Light gasoline having a boiling range of about 20 - 100 °C
• • 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
  • C10G2300/1037—Hydrocarbon fractions
  • C10G2300/1044—Heavy gasoline or naphtha having a boiling range of about 100 - 180 °C
• • 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
  • C10G2300/1037—Hydrocarbon fractions
  • C10G2300/1048—Middle distillates
  • C10G2300/1055—Diesel having a boiling range of about 230 - 330 °C
• • 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
  • C10G2300/205—Metal content
• • 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
  • C10G2300/40—Characteristics of the process deviating from typical ways of processing
  • C10G2300/4037—In-situ processes

Definitions

• the invention relates generally to a process, method, and system for removing heavy metals such as mercury and the like from hydrocarbon fluids such as crude oil.
• Heavy metals such as lead, zinc, mercury, arsenic, silver and the like can be present in trace amounts in all types of fuels such as crude oils. It is desirable to remove the trace elements of these metals from crude oils.
• Hg(0) elemental dissolved Hg(0) and particulate Hg (liquid droplets or liquid Hg adhering to sand particles).
• Hg particulates or fine HgS and/or HgO crystals precipitated upon treatment of the liquid hydrocarbon hydrocyclones and / or filters are typically used. Filtering crude oil to remove HgS and / or HgO and other Hg-containing solids is expensive and cumbersome.
• 2010/0051553 discloses the removal of mercury from liquid streams such as non-aqueous liquid hydrocarbonaceous streams upon contact with a Hg-complexing agent for mercury to form insoluble complexes for subsequent removal.
• a Hg-complexing agent for mercury to form insoluble complexes for subsequent removal.
• a method to reduce mercury in a crude oil comprises converting at least a portion of mercury in the crude oil to mercuric iodide in an oil-water emulsion upon contact with a molecular iodine source; and separating the water containing the soluble mercuric iodide from the crude oil for a treated crude oil having a reduced concentration of mercury.
• the invention in another aspect, relates to a method to reduce or remove trace elements of heavy metals such as mercury from a crude oil.
• the method comprises converting at least a portion of mercury in the crude oil to mercuric iodide in an oil-water emulsion upon contact with an iodine source, wherein molecular iodine is generated in-situ in an oxidation-reduction reaction between an iodine species having a negative charge and an oxidizing reagent; and separating the water containing the soluble mercuric iodide from the crude oil for a treated crude oil having a reduced concentration of mercury.
• the molecular iodine is generated in-situ in an oxidation- reduction reaction between an iodine species having a positive charge and a reducing reagent.
• a complexing agent is further added to the crude oil to form a water-soluble heavy metal compound, for the water containing the soluble heavy metal compound to be subsequently separated from the crude oil, resulting in a treated crude oil having a reduced concentration of heavy metal.
• “Crude oil” refers to natural and synthetic liquid hydrocarbon products including but not limited to petroleum products; intermediate petroleum streams such as residue, naphtha, cracked stock; refined petroleum products including gasoline, other fuels, and solvents.
• the liquid hydrocarbon products can be directly from oil wells or after the products have been further processed or derived.
• the term “petroleum products” refer to crude oil, solid, and semi-solid hydrocarbon products including but not limited to tar sand, bitumen, etc.
• the term “petroleum products” also refer to petroleum products derived from coal.
• Heavy metals refer to gold, silver, mercury, platinum, palladium, iridium, rhodium, osmium, ruthenium, arsenic, and uranium.
• Race element refers to the amount of heavy metals to be removed from the crude oil, or for the concentration to be significantly reduced.
• the amount of trace element varies depending on the crude oil source and the type of heavy metal, for example, ranging from a few ppb to up to 30,000 ppb for mercury.
• Mercury sulfide may be used interchangeably with HgS, referring to mercurous sulfide, mercuric sulfide, or mixtures thereof. Normally, mercury sulfide is present as mercuric sulfide with a stoichiometric equivalent of one mole of sulfide ion per mole of mercury ion.
• Mercury salt or “mercury complex” meaning a chemical compound formed by replacing all or part of hydrogen ions of an acid with one or more mercury ions.
• Oil-water as used herein means any mixture containing a crude oil with water, inclusive of both oil-in- water emulsions and water-in-oil emulsions.
• the emulsion particles are of droplet sizes.
• the emulsion particles are of micron or nano particle sizes.
• oil is present as fine droplets contained in water in the form of an emulsion, i.e., emulsified hydrocarbons, or in the form of undissolved, yet non-emulsified hydrocarbons.
• Interphase or “interphase layer” or “interface layer” or “emulsion layer” may be used interchangeably, referring to the layer in between the oil and water phases, having characteristics and properties different from the oil and water phases.
• the interface layer is a cloudy layer in between the water and oil phases.
• the interface layer comprises a plurality of aggregates of coalescence (or droplets), with the aggregates being randomly dispersed in either the water phase or the oil phase.
• Complexing agent or “chelating agent” refers to a compound that is capable of reacting with another chemical group, e.g., mercury compounds, to form a covalent bond, i.e. is covalently reactive under suitable reaction conditions.
• Crudes and crude blends are used interchangeably and each is intended to include both a single crude and blends of crudes.
• Crudes may contain small amounts of heavy metals such as mercury, which may be present as elemental mercury Hg°, ionic Hg, inorganic mercury compounds, and / or organic mercury compounds.
• Examples include but are not limited to: mercuric halides (e.g., HgXY, X and Y could be halides, oxygen, or halogen-oxides), mercurous halides (e.g., Hg 2 XY, X and Y could be halides, oxygen, or halogen-oxides), mercuric oxides (e.g., HgO), mercuric sulfide (e.g., HgS, meta-cinnabar and/or cinnabar), mercuric sulfate (HgS0 4 ), mercurous sulfate (Hg 2 S0 4 ), mercury selenide (e.g., HgSe 2 , HgSeg, HgSe), mercury hydroxides, and organo-mercury compounds (e.g., alkyl mercury compounds) and mixtures of thereof.
• Mercury can be present in various forms, e.g., in
• the invention effectively decreases the levels of heavy metals such as mercury, lead, zinc, etc. from crude oil.
• the mercury in crude oil is converted into a water soluble form that would partition into the aqueous phase for subsequent separation and convenient disposal by methods including but not limited to re- injection, or disposed back into the reservoir.
• the mercury is converted into soluble by-products upon reaction with molecular iodine (I 2 ), metallic mercury (Hg°) being converted into mercury ions (Hg 2+ ), subsequently forming aqueous soluble Hg 2+ complexes.
• the crude oil is first brought into contact with iodine, or a compound containing iodine such as alkali metal salts of iodine, e.g., halides or iodide of a cation.
• iodide is selected from ammonium iodide, alkali metal iodide, an alkaline earth metal iodide, and
• the amount of the iodine is chosen to result in an atomic ratio of iodine to mercury of at least 1 : 1. In a second embodiment, a ratio ranging from 1.5: 1 to 6: 1. In a third embodiment, a ratio of 2: 1 to 4: 1.
• the crude oil is brought into contact with solid iodine.
• an iodine solution in petroleum distillate is injected into the liquid hydrocarbon, e.g., gas condensate or crude oil.
• molecular iodine (I 2 ) Upon contact with the crude oil, molecular iodine (I 2 ) reacts with elemental Hg droplets, elemental Hg adsorbed on formation minerals, elemental Hg dissolved in the crude oil, as well as mercury compounds including but not limited to HgS, HgSe, and HgO.
• Hg° is oxidized to Hg 2+
• I 2 is reduced to 2T.
• a slight excess of iodine is employed to prevent the formation of water insoluble Hg 2 I 2 .
• Mercuric iodide is highly soluble in water and not very soluble in hydrocarbons.
• Hgl 2 (solution) + Hg° (liquid) Hg 2 I 2 (solid)
• Hg 2 I 2 (solid) + I 2 (solution) 2HgI 2 (solution) -> 2Hg 2+ (aq) + 4I " (aq).
• Elemental iodine is a rather expensive reagent. Elemental iodine is in the form of crystals, which sublime readily to generate a violet colored vapor. Other chemicals are often used to combine in some form with elemental iodine to provide stable preparations.
• a reagent instead of using molecular iodine I 2 , a reagent is used which reacts with at least an iodide salt to covert iodine anion (T) to molecular iodine (I 2 ) in an oxidation-reduction reaction, allowing for the economical in-situ generation of I 2 .
• the crude oil is brought into contact with an oxidizing agent and a negatively charged iodine, or the crude oil can be brought into contact with a reducing agent plus a positively charged iodine.
• molecular iodine is formed by reducing an iodine species with a positive oxidation state (a positively charged iodine) or oxidizing a negatively charged iodine (iodide T). Reagents with lower oxidation potentials can be used to reduce the iodine species to molecular iodine. Reagents with a higher oxidation potential than iodide can oxidize iodide into molecular iodine.
• Iodine species exist in different oxidation states.
• the positive oxidation states are usually found in inorganic species such as acids, salts, oxides, or halides.
• the negative oxidation states appear in iodine species that are in the form of iodide salts or organic iodo- compounds.
• iodide salts include but are not limited to iodides selected from the group of ammonium, alkali metal, and alkaline earth metal.
• Examples of iodine species with a positive oxidation state that can be used to generate molecular iodine in-situ include but are not limited to: periodic acid ( ⁇ 5 ⁇ 0 6 ), potassium periodate (KIO 4 ), sodium periodate (NaI0 4 ) all with oxidation state of +7; iodic acid (HIO3), potassium iodate (KIO3), potassium hydrogen iodate (KHI 2 0 6 ), sodium iodate (NaI0 3 ), iodine oxide (I 2 0 5 ), all with oxidation state of +5; iodine trichloride (IC1 3 ) with oxidation state of +3; iodine monobromide (IBr), iodine monochloride (IC1) all with oxidation state of +1.
• periodic acid ⁇ 5 ⁇ 0 6
• KIO 4 potassium periodate
• NaI0 4 sodium periodate
• iodic acid HIO3
• Iodine compounds with negative oxidation state (-1) include but are not limited to hydriodic acid (HI), sodium iodide (Nal), potassium iodide (KI), ammonium iodide (NH 4 I), aluminum iodide (A1I 3 ), boron triodide (BI 3 ), calcium iodide (Cal 2 ), magnesium iodide (Mgl 2 ), iodoform (CHI 3 ), tetraiodoethylene (C 2 I 4 ), iodoethanol, iodoacetic anhydride, iododecane, and iodobenzene.
• HI hydriodic acid
• Naal sodium iodide
• KI potassium iodide
• NH 4 I ammonium iodide
• Al aluminum iodide
• BI 3 boron triodide
• Ca 2 calcium iodide
• Mgl 2 magnesium
• a reagent that is an iodine reductant is used to react with an iodine species having a positive oxidation state to generate molecular iodine in-situ.
• reagents that function as iodine reductants include but are not limited to thioureas, thiols, ascorbates, imidazoles, and thiosulfates such as sodium thiosulfate.
• a reagent that is an iodine oxidant is employed to react with a source of iodine anion to generate molecular iodine in-situ.
• the excess negatively charged iodides function as complexing agents, moving mercury compounds from the oil phase and / or the interphase to the water phase for subsequent removal.
• oxidizing reagents that can be used to generate iodine in-situ include but are not limited to sources of peroxide (including hydrogen peroxide, urea peroxide, peroxy acids,
• alkylperoxides, etc. bromine (Br 2 ), ozone (O3), cumene hydroperoxide, t-butyl
• hydroperoxide NaOCl
• iodate such as potassium iodate KIO3 and sodium iodate NaI0 3
• monopersulfate percarbonate, perchlorate, permanganate, perphosphate, and peroxidases that are capable of oxidizing iodide.
• the reaction can be at atmospheric pressure and ambient temperature.
• the molecular iodine will convert Hg° into mercury ions Hg 2+ , with excess T from the iodide salt forming water soluble Hg-I complexes.
• the ratio of molecular iodine generated in-situ with starting iodine materials ranges between 0.5 - 1 in one embodiment. In a second embodiment, the ratio ranges from 0.65 to 1. In a third embodiment, from 0.8 to 1. In a fifth embodiment, from 0.95 to 1. In one embodiment, the higher the ratio of molecular iodine to total iodine, the higher the removal of trace elements from the crude oil.
• the rate of iodine generation is quite rapid with at least 50% of the equilibrium concentration of the molecular iodine being generated within the first 10 minutes of contact between the starting reagents.
• the molar ratio of iodine to heavy metals such as mercury ranges from at least 1 : 1 to 30,000: 1 in one embodiment; from 2: 1 to 1,000: 1 in a second embodiment; from 5: 1 to 100: 1 in a third embodiment; greater than 3: 1 in a fourth embodiment, and less than 10,000: 1 in a fifth embodiment.
• the amount is sufficient to form water soluble Hg 2+ complexes in the system.
• a complexing agent is also added to the crude oil to extract the mercury cations from the oil phase and / or the interphase to the water phase.
• the complexing agent essentially forms a soluble mercury compound, e.g., mercury complexes, when contacting the mercury cations.
• a complexing agent having a large equilibrium binding constant for non-complexed mercury ions is selected.
• Examples include thiol groups, dithiocarbamic acid, thiocarbamic acid, thiocarbazone, cryptate, thiophene groups, thioether groups, thiazole groups, thalocyanine groups, thiourenium groups, amino groups,
• complexing agents include but are not limited to hydrazines, sodium metabisulfite (Na 2 S 2 05), sodium thiosulfate (Na 2 S 2 0 3 ), thiourea, the group of sulfides, ammonium thiosulfate, alkali metal thiosulfates, alkaline earth metal thiosulfates, iron thiosulfates, alkali metal dithionites, alkaline earth metal dithionites, and mixtures thereof.
• sulfides include but are not limited to potassium sulfide, alkaline earth metal sulfides, sulfides of transition elements number 25— 30, aluminum sulfides, cadmium sulfides, antimony sulfides, Group IV sulfides, and mixtures thereof.
• the inorganic sulfur complexing agents are oxygen- containing compounds such as thiosulfates and dithionites.
• examples include alkali metal thiosulfates, alkaline earth metal thiosulfates, iron thiosulfates, alkali metal dithionites, and alkaline earth metal dithionites and mixtures thereof.
• Suitable alkali metal thiosulfates include ammonium thiosulfate, sodium thiosulfate, potassium thiosulfate, and lithium thiosulfate.
• alkaline earth metal thiosulfates include calcium thiosulfate and magnesium thiosulfate.
• Ferric thiosulfate exemplifies an iron thiosulfate which may be employed.
• Alkali metal dithionites include sodium dithionite and potassium dithionite.
• Calcium dithionite is suitable as an alkaline earth metal dithionite complexing agent.
• the complexing agent is a polyamine for forming stable cationic complexes with the ions of heavy metals.
• exemplary polyamines include
• the polyamine may include carboxyl groups, hydroxyl groups and / other substituents, as long as they do not weaken the complex formed with polyamine.
• the complexing agent is tetraethylenepentamine (TETREN), which forms a stable complex with mercury at a pH around 4.
• the complexing agent is selected from the group of
• DEDCA diethyl dithiocarbamic acid in a concentration of 0.1 to 0.5M, DMPS (sodium 2,3- dimercaptopropane-1 -sulfonate), DMSA (meso-2,3-dimercaptosucccinic acid), EDTA (ethylene-diamine-tetra-acetic acid), DMSA (Dimercaptosuccinic acid), BAL (2,3- dimercapto-propanol), CDTA (1,2-cyclohexylene-dinitrilo-tetraacetic acid), DTPA
• NAC diethylene triamine pentaacetic acid
• NAC N-acetyl L-cystiene
• sodium 4,5- dihydroxybenzene-l,3-disulfonate polyaspartates
• HACA hydroxyaminocarboxylic acid
• HEIDA hydroxyethylimmodiacetic
• IDS iminodisuccinic acid
• NTA nitrilotriacetic acid
• NAA sodium gluconate
• the complexing agents are employed in a sufficient amount to effectively stabilize (forming complexes with) the soluble heavy metals in the oil-water mixture.
• the molar ratio of complexing agent to soluble mercury in the mixture ranges from 1 : 1 to about 5,000: 1. In a second embodiment from 2: 1 to about 3,000: 1. In a third embodiment from 5 : 1 to about 1 ,000: 1. In a fourth embodiment, from 20: 1 to 500: 1. In a fifth embodiment, the amount is sufficient to form water soluble Hg 2+ complexes in the system.
• iodine is soluble in crude oil
• iodine is introduced into the crude oil as a solid, with the crude oil being routed through a column or bed containing solid iodine provided as tablets, in granular form, or as finely divided iodine.
• iodine is added to the crude oil as a solution in solvents such as methanol, naphtha, diesel, gasoline, mercury-free crude oil, solvents, and the like.
• iodine may be introduced into the crude oil as a gas with the iodine-containing gas stream being sparged into a pipeline or vessel containing crude oil at various intervals, using means known in the art.
• the iodine-containing gas stream may be formed by providing a solid iodine source and contacting the solid iodine with an inert gas stream, e.g., helium, nitrogen, argon, and air.
• the solid iodine source may be finely divided iodine.
• the gas stream is provided at a predetermined temperature selected to vaporize the solid iodine at a pre-selected rate.
• an oxidizing agent is first prepared or obtained.
• the oxidizing agent can be prepared in an aqueous form.
• an organic oxidizing agent is used.
• the oxidant is brought in contact with the crude oil containing heavy metals, e.g., trace elements of mercury and the like, by means known in the art and in a sufficient (or effective amount) for to convert at least a portion of, e.g., at least 50%, of the heavy metals into cations.
• a sufficient amount is added for at least 80% conversion.
• at least 95% conversion is added.
• a reagent containing iodine species is prepared / provided for the generation of iodine in-situ, and subsequently, for the reaction of iodine and mercury to form water soluble complexes.
• a complexing agent is further added to extract cationic mercury from the oil phase / interphase into the water phase.
• an iodine column is first prepared by adsorbing the iodine species, e.g., KI 3 , to a strong anion exchanger, e.g., containing tertiary amine groups.
• iodine is released from the column, i.e., being reduced to iodide, upon contact with a solid adsorbent containing the reagent that would function as the reductant / oxidant.
• a thiol-containing adsorbent is used for the reducing step, releasing free iodine (as generated in-situ).
• the feeding of the iodine containing compound and / or reductant and / or oxidant and / or complexing agents can be separate, or together as one composition.
• the oxidant and complexing agent containing iodine species are first combined, then brought into contact with the crude oil.
• the iodine containing species is first brought into contact with the crude oil, followed by the addition of the oxidant.
• the oxidant is first mixed with the crude oil, then followed by the addition of a complexing agent containing iodine species.
• crude oil is first brought into contact with an oxidizing agent and a negatively charged iodine reagent, followed by the addition of a complexing agent to extract the cationic mercury into the water phase.
• a complexing agent to extract the cationic mercury into the water phase.
• crude oil is first brought into contact with a reducing agent and a positively charged iodine reagent, followed by the addition of a complexing agent to extract the cationic mercury into the water phase.
• the amount of reagents, i.e., oxidant, reductant, or iodine containing species should be sufficient to convert the heavy metals in the crude oil into heavy metal cations, and subsequently, into water soluble heavy metal complexes.
• the added reagents make up from 0.5 to 50 volume percent of the total mixture (of crude oil and reagents).
• the added reagents make up less than 40 vol. % of the mixture.
• mercury removal can be enhanced at a low pH
• the reagent is an acidic thiourea, with an acid concentration of up to 5 M and thioureas concentration from 0.3 to 1.5M.
• liquid reagents is introduced by utilizing high mechanical shearing such as those produced by forcing the liquid, under pressure, through fine hole nozzles or by utilizing dual fluid nozzles where the iodine generating reagent is atomized by a compressed fluid (e.g., air, steam or other gas).
• a compressed fluid e.g., air, steam or other gas.
• the components selected in making the iodine in- situ can be ground separately or in combination, if suitable, to a fine powder and injected/blown into a gas stream at appropriate temperatures for introduction into the crude oil.
• Liquid reagent component(s) can also be mixed with powder reagent components for introduction into the crude oil.
• the rate of in-situ iodine generation is rapid with at least 75% of the equilibrium concentration of molecular iodine being generated within the first 10 minute of contact between the specific iodine generating chemical agents and the crude oil.
• the at least 75% rate is achieved within the first 5 minutes.
• at least 90% rate is achieved within the first 10 minutes.
• composition(s) can be introduced or fed continuously or intermittently, i.e., batch-wise, into operating gas or fluid pipelines, for example. Some of the reagents can be fed continuously, while other compositions can be fed intermittently. Alternatively, batch introduction is effective for offline pipelines.
• the contact can be at any temperature that is sufficiently high enough for the crude oil to be completely liquid. In one embodiment, the contact is at room temperature. In another embodiment, the contact is at a sufficiently elevated temperature, e.g., at least 50°C. In one embodiment, the contact time is at least a minute. In another embodiment, the contact time is at least 5 minutes. In a third embodiment, at least 1 hr. In a fourth embodiment, the contact is continuous for at least 2 hrs. [058] In one embodiment, the iodine is introduced into the crude oil for a final concentration of 25 - 100 ppm.
• iodine is added to the crude oil as a mixture with a complexing agent reagent such as potassium iodide KI in concentrations of 5 wt. % KI, 10 wt. % KI, 20 wt. % KI, or 40 wt. % KI (mixtures also known as Lugol's Solution). Concentration of I 2 added can be controlled by means known in the art, including mass or volume flow controllers, online analyzers, ORP (redox potential) and iodine ion specific detection instruments. Potassium iodide combines with mercuric iodide to form a water soluble compound K 2 HgI 4 .
• a complexing agent reagent such as potassium iodide KI in concentrations of 5 wt. % KI, 10 wt. % KI, 20 wt. % KI, or 40 wt. % KI (mixtures also known as Lugol's Solution). Concentration of
• RX or RX 2 water soluble halide having the formula RX or RX 2 can also be used as complexing agents, with R being selected from the group consisting of potassium, lithium, sodium, calcium, magnesium, and ammonium and X is iodide, bromide or chloride.
• R being selected from the group consisting of potassium, lithium, sodium, calcium, magnesium, and ammonium
• X is iodide, bromide or chloride.
• an aqueous solution containing sodium iodide and sodium iodate is employed to essentially convert 100% of the iodide to molecular iodine.
• the water phase containing the heavy metal complexes can be separated from the crude oil in a phase separation device known in the art, e.g., a cyclone device, electrostatic coalescent device, gravitational oil-water separator, centrifugal separator, etc., resulting in a treated crude oil with a significantly reduced level of heavy metals.
• the heavy metal complexes can be isolated / extracted out of the effluent and subsequently disposed.
• mercury is electrochemically removed from the aqueous extractant to regenerate a mercury-free aqueous extractant composition.
• the mercury removal in one embodiment is done in the field, i.e., close to or at the upstream wellhead, for better quality crude to sell to the refinery.
• the crude can be treated in a facility at the wellhead or on an off-shore platform, or right in the pipeline used to transport the crude to ports or refineries.
• the mixing of crude oil with the iodine source, and other materials such as oxidizing agents, in one embodiment is achieved with motion by pump stations along the pipeline.
• the mercury removal is a process integrated with the refinery and downstream from the wellhead.
• the crude oil feed has an initial mercury level of at least 50 ppb.
• the initial level is at least 5,000 ppb.
• Some crude oil feed may contain from about 2,000 to about 100,000 ppb mercury.
• the mercury level in the crude oil after iodine treatment is reduced to 100 ppb or less.
• the level is brought down to 50 ppb or less.
• the level is 20 ppb or less.
• the level is 10 ppb or less.
• the level is 5 ppb or less.
• the removal or reduction is at least 50% from the original level of heavy metals such as mercury or arsenic. In a fifth embodiment, at least 75% of a heavy metal such as mercury is removed. In a seventh embodiment, the removal or the reduction is at least 90%>.
• Mercury level can be measured by conventional techniques known in the art, including but not limited to cold vapor atomic absorption spectroscopy (CV-AAS), cold vapor atomic fluorescence spectroscopy (CV-AFS), gas chromatography combined with inductively coupled plasma mass spectrometry (or GC-ICP-MS with 0.1 ppb detection limit), and combustion amalgamation, etc.
• CV-AAS cold vapor atomic absorption spectroscopy
• CV-AFS cold vapor atomic fluorescence spectroscopy
• gas chromatography combined with inductively coupled plasma mass spectrometry or GC-ICP-MS with 0.1 ppb detection limit
• combustion amalgamation etc.
• I 2 is corrosive, thus its use requires precaution with appropriate materials.
• Equipment for use in containing and / or handling I 2 such as storage containers, pumps, injection quills in one embodiment is made of, or coated with materials such as Teflon, polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), high nickel alloys, and the like.
• I 2 is introduced or mixed into the crude oil at a fairly low concentration, e.g., 25-200 ppm for example, normal carbon steel typically used for equipment containing crude oil is sufficient and not affected by the corrosivity inherent with I 2 . Additionally, as I 2 oxidation of heavy metals occurs and I 2 is reduced to ⁇ . Corrosion due to iodide is also less of an issue, particularly when complexing agents such as thiosulfate and the like are further added to the crude oil mixture.
• Example 1 50 mL of mercury vapor feed preparation containing
• Example 2 50 mL of distilled water was placed in each of a number of 250 mL glass tubes, and the mercury level was measured using LUMEX mercury analyzer equipped with PYRO-915+. 50 mL of mercury vapor feed preparation containing approximately 400 ppb Hg was added to each of the glass tubes, then mercury level was measured using LUMEX mercury analyzer equipped with PYRO-915+. A pre-determined volume of hydrogen peroxide (0.3%> H 2 0 2 ) stock solution was added to each of the tubes at molar ratio of H 2 0 2 to Hg of 246: 1. The mixture was stirred up for 1 minute at 600 rpm.

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