WO2012068277A2 - Process, method, and system for removing heavy metals from fluids - Google Patents

Process, method, and system for removing heavy metals from fluids Download PDF

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Publication number
WO2012068277A2
WO2012068277A2 PCT/US2011/061035 US2011061035W WO2012068277A2 WO 2012068277 A2 WO2012068277 A2 WO 2012068277A2 US 2011061035 W US2011061035 W US 2011061035W WO 2012068277 A2 WO2012068277 A2 WO 2012068277A2
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WO
WIPO (PCT)
Prior art keywords
crude oil
mercury
water
oxidizing agent
complexing agent
Prior art date
Application number
PCT/US2011/061035
Other languages
English (en)
French (fr)
Other versions
WO2012068277A3 (en
Inventor
Sujin Yean
Original Assignee
Chevron U.S.A. Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US12/950,060 external-priority patent/US8728303B2/en
Priority claimed from US12/950,637 external-priority patent/US8721874B2/en
Priority claimed from US12/950,170 external-priority patent/US8721873B2/en
Priority to AU2011328930A priority Critical patent/AU2011328930A1/en
Priority to SG2013035829A priority patent/SG190775A1/en
Priority to CA2818273A priority patent/CA2818273A1/en
Application filed by Chevron U.S.A. Inc. filed Critical Chevron U.S.A. Inc.
Priority to CN2011800589006A priority patent/CN103249814A/zh
Priority to RU2013127659/04A priority patent/RU2013127659A/ru
Priority to EP11841430.9A priority patent/EP2640810B1/de
Priority to BR112013012087A priority patent/BR112013012087A2/pt
Publication of WO2012068277A2 publication Critical patent/WO2012068277A2/en
Publication of WO2012068277A3 publication Critical patent/WO2012068277A3/en

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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
    • C10G27/10—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation with oxygen or compounds generating oxygen in the presence of metal-containing organic complexes, e.g. chelates, or cationic ion-exchange resins
    • 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
    • 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
    • C10G27/12—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation with oxygen or compounds generating oxygen with oxygen-generating compounds, e.g. per-compounds, chromic acid, chromates
    • 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
    • C10G27/14—Refining of hydrocarbon oils in the absence of hydrogen, by oxidation with oxygen or compounds generating oxygen with ozone-containing gases
    • 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
    • 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
    • C10G2300/205—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
    • C10G2300/20—Characteristics of the feedstock or the products
    • C10G2300/30—Physical properties of feedstocks or products
    • C10G2300/308—Gravity, density, e.g. API
    • 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
    • C10G2300/80—Additives
    • 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
    • C10G2300/80—Additives
    • C10G2300/805—Water

Definitions

  • the invention relates generally to a process, method, and system for removing heavy metals such as mercury, arsenic, and the like from hydrocarbon fluids such as crude oil.
  • Heavy metals such as lead, zinc, mercury, silver, arsenic and the like can be present in trace amounts in all types of hydrocarbon streams such as crude oils.
  • amounts of a heavy metal such as arsenic are associated with the mercury level. The amount can range from below the analytical detection limit (0.5 ⁇ g/kg) to several thousand ppb depending on the feed source. It is desirable to remove the trace amounts of these metals from crude oils.
  • US Patent Application No. 2010/0078358 discloses the use of NaOCl as the oxidizing agent for converting at least a portion of Hg(0) to Hg(II). However, there is still a need to extract or convert the free mercury ions into a form that can be easily recovered and disposed.
  • US Patent Publication No. 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.
  • the invention relates to an improved method to treat a crude oil to reduce its heavy metal concentration.
  • a water stream consisting essentially of an oxidizing agent is added to the crude oil to extract at least a portion of the heavy metals into the water stream forming a waste stream.
  • the improvement comprises adding a complexing agent, facilitating the formation of soluble compounds in the water stream, prior to separating the wastewater from the crude oil, leaving a treated crude oil having a reduced heavy metal level.
  • the invention in another aspect, relates to a method for reducing a trace amount of heavy metals, e.g., mercury, arsenic, etc., in a crude oil.
  • the method comprises mixing into the crude oil an amount of an oxygen-containing compound selected from the group of oxyhalites, hydroperoxides, and organic peroxides, inorganic peracids, organic peracids, molecular halogens such as iodine (I 2 ), bromine (Br 2 ), and ozone to extract the heavy metals into a water-oil emulsion; adding an amount of a complexing agent to the water-oil emulsion to facilitate the formation of soluble heavy metal complexes in the water phase; and separating the water containing the soluble heavy metal complexes from the crude oil, leaving a treated crude oil having a reduced concentration of heavy metals such as arsenic and or mercury.
  • an oxygen-containing compound selected from the group of oxyhalites, hydroperoxides,
  • the invention relates to a method for reducing a trace amount of arsenic in a crude oil.
  • the method comprises: mixing into the crude oil an effective amount of at least an oxidizing agent selected from the group of oxyhalites, hydroperoxides, organic peroxides, inorganic peracids and salts thereof, organic peracids and salts thereof, molecular halogens, ozone and combinations thereof to extract at least a portion of arsenic into a water-oil emulsion as arsenic cations, forming a mixture; adding an effective amount of a complexing agent to the water-oil emulsion mixture to convert the extracted arsenic cations to water-soluble arsenic compounds in a water phase; and separating the water phase containing the water-soluble arsenic compounds from the crude oil to obtain a treated crude oil having a reduced concentration of arsenic.
  • an oxidizing agent selected from the group of oxyhalites, hydroperoxides, organic
  • Caste oil refers to a liquid hydrocarbon material.
  • Hydrocarbon material refers to a pure compound or mixtures of compounds containing hydrogen and carbon and optionally sulfur, nitrogen, oxygen, and other elements. Examples include crude oils, synthetic crude oils, petroleum products such as gasoline, jet fuel, diesel fuel, lubricant base oil, solvents, and alcohols such as methanol and ethanol.
  • crude oil has a specific gravity of at least 0.75 at a temperature of 60°F. In another embodiment, the specific gravity is at least 0.85. In a third embodiment, the specific gravity is at least 0.90.
  • Heavy metals refers to gold, silver, mercury, osmium, ruthenium, uranium, cadmium, tin, lead, and arsenic. In one embodiment, “heavy metals” refers to mercury.
  • Race amount refers to the amount of heavy metals in the crude oil. The amount 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 and arsenic.
  • 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” means a chemical compound formed by replacing all or part of hydrogen ions of an acid with one or more mercury ions.
  • Arsenic salt or "arsenic complex” means a chemical compound formed by replacing all or part of hydrogen ions of an acid with one or more arsenic ions, e.g., As 3+ or As 5+ .
  • Oil-water or “oil- water emulsion” or “emulsion” or “emulsions” in the context of oil-water (or water-oil) emulsion refers to an admixture containing a crude oil with water, inclusive of both oil-in- water emulsions and water-in-oil emulsions.
  • emulsion includes locations within an oil-water mixture in which heavy metal concentrates, including interfaces and interface layers.
  • emulsion is present in the initial product of oil and produced water from the reservoir. In another embodiment, it is formed during the mixing of the crude oil with the oxidizing agent and / or the complexing agent.
  • Embodision can be stable or unstable, such as in dispersions of oil and water which can subsequently separate; e.g., an oil-water mixture left standing for 10 minutes at room
  • oil-water emulsion particles are of droplet sizes. In another embodiment, the emulsion particles are the size of micron or nano particles. In one embodiment of oil-water emulsion, oil is present as fine droplets contained in water in the form of an emulsion, e.g., emulsified hydrocarbons, or in the form of undissolved, yet non-emulsified hydrocarbons. In another embodiment, oil-water emulsion refers to a mixture which after mixing and allowed to stand undisturbed, a portion of the mixture is resolved into separate phases in 10 seconds. In yet another embodiment, less than 50% of the mixture is resolved in separate phases in 10 seconds.
  • Interphase or “interphase layer,” or “interface layer,” or “emulsion layer” may be used interchangeably, referring to the layer between the oil and water phases, having characteristics and properties different from the oil and water phases.
  • the interface layer is a cloudy layer 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 a heavy metal compound, e.g., mercury or arsenic compounds.
  • Oxidant may be used interchangeably with “oxidizing agent,” referring to compound that oxidizes heavy metals such as mercury to form mercury cations.
  • Soluble refers to materials that dissolve in water, in conjunction with heavy metal removal, meaning materials that are able to dissolve in water at concentrations comparable to the original concentration of the heavy metals in the crude oil (e.g., 1 ppb or greater).
  • Halogens refers to diatomic species from the column of the periodic table headed by fluorine, for example F 2 , Cl 2 , Br 2 , 1 2 , etc.
  • Halogen oxides refers to molecules which combine one or more halogen atoms and oxygen, for example NaCIO, C10 2 , NaC10 4 .
  • Organic peracids refers to multiple-carbon organic compounds where the -OH in an acid group has been replaced with a -OOH group, e.g. a compound of the general formula RCO-OOH. Examples include but are not limited to peracetic acid, perbenzoic acid, meta- chloroperoxybenzoic acid and combinations thereof.
  • Inorganic peracids refers to compounds of sulfur, phosphorous, or carbon where the -OH in an acid group has been replaced with a -OOH group. Examples include but are not limited to peroxydiphosphoric acid, H 4 P 2 08 and peroxydisulfuric acid, H 2 S 2 08, sodium percarbonate Na 2 C0 3 ⁇ 1.5H 2 0 2 , sodium peroxydisulfate Na 2 S 2 0 8 , potassium peroxydisulfate K 2 S 2 08, ammonium peroxydisulfate (NH 4 ) 2 S 2 08, and combination thereof.
  • peroxydiphosphoric acid H 4 P 2 08 and peroxydisulfuric acid
  • H 2 S 2 08 sodium percarbonate Na 2 C0 3 ⁇ 1.5H 2 0 2
  • sodium peroxydisulfate Na 2 S 2 0 8 sodium peroxydisulfate Na 2 S 2 0 8
  • potassium peroxydisulfate K 2 S 2 08 ammonium peroxydisulf
  • Crude, crude oil, crudes and crude blends are used interchangeably and each is intended to include both a single crude and blends of crudes.
  • the crude oil to be treated is in the form of a mixture of crude oil and produced water.
  • the water-to-oil ratio increases with the age of the crude oil source, as the production of oil declines with the age of the well.
  • the crude stream to be treated may contain little if any produced water.
  • the amount of produced water can be as much as 98% of the crude stream to be treated.
  • the crude oil or crude oil feed to be treated refers to both crude oil by itself as well as crude oil-water mixtures.
  • Crudes may contain small amounts of heavy metals such as mercury and / or arsenic.
  • mercury 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 ,
  • the arsenic species present can be in any of the forms triphenylarsine (Ph 3 As), triphenylarsine oxide (Ph 3 AsO), arsenic sulfide minerals (e.g., As 4 S 4 or AsS or As 2 S 3 ), metal arsenic sulfide minerals (e.g., FeAsS; (Co, Ni, Fe)AsS; (Fe, Co)AsS), arsenic selenide (e.g., As 2 Ses, As 2 Se 3 ), arsenic- reactive sulfur species, organo-arsenic species, and inorganic arsenic held in small water droplets.
  • triphenylarsine Ph 3 As
  • Ph 3 AsO triphenylarsine oxide
  • arsenic sulfide minerals e.g., As 4 S 4 or AsS or As 2 S 3
  • metal arsenic sulfide minerals e.g., FeAsS;
  • crude oil is effectively treated to decrease trace levels of heavy metals such as mercury, lead, arsenic, etc.
  • the crude oil is brought into contact with an oxidant.
  • a complexing agent is added to the crude oil / oxidant mixture to extract at least a portion of the oxidized heavy metal complexes from the interphase to the water phase.
  • the crude oil is brought into contact with a composition containing both the oxidizing agent and the complexing agent to form a soluble mercury compound.
  • Mercury in the water phase is subsequently recovered.
  • the arsenic species become arsenate, which is negatively charged.
  • complexing agents for the creation of strong complexes with arsenic species are injected into the hydrocarbon or water mixtures to form highly water-soluble complexes that can be subsequently removed from the crude oil. By-products of arsenic complexes will preferentially partition into the water phase.
  • the water containing mercury / arsenic in one embodiment can be injected back into the reservoir for water flooding, or reservoir pressure support, as a mean to dispose of the heavy metals that were originally present in the crude oil.
  • Oxidizing Agent In one embodiment, the crude oil is brought into contact with an excess amount of oxidant under suitable conditions to oxidize at least a portion of the heavy metals to cations.
  • An organic oxidizing agent or an oxidant in an aqueous form can be used.
  • pH typically is typically in the range of 6.5 to 8
  • the charge of the arsenic species present is neutral (H 3 ASO 3 0 ) or anions (H 2 As0 4 ⁇ , or HAs0 4 2 ⁇ ).
  • the oxidizing agent oxidizes reduced forms of arsenic, e.g., arsine or other organic arsenic forms (soluble in hydrocarbons), or arsenite (soluble in water) to the 5+ oxidation state.
  • arsenic compounds are oxidized into inorganic arsenic species such as arsenite (As 3 ) or arsenate (As 5 ).
  • the oxidant 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, HgO, converting at least a portion of elemental mercury (Hg°) to cations, having an oxidation state equal to or greater than 1 (e.g., Hg 2+ ).
  • the amount of oxidants used should be at least equal to the amount of heavy metal to be removed on a molar basis, if not in an excess amount.
  • an amount of oxidants (and the water stream containing oxidants) is added for a molar ratio of oxidant to heavy metals ranging from 1.5: 1 to 30,000: 1.
  • an amount of water containing oxidants is provided for a molar ratio of oxidant to heavy metals ranging from 5 : 1 to 20,000: 1.
  • the amount is a molar ratio of oxidants to heavy metals ranging from 50: 1 to 10,000: 1.
  • the amount is molar ratio ranging from 100: 1 to 5,000: 1.
  • the ratio ranges from 150: 1 to 500: 1.
  • the contact can be carried out at room temperature or at an elevated temperature (e.g., 30 - 80°C) for a period of time, general y ranging from seconds to 1 day. In one embodiment, the contact is between 20 seconds to 5 hours. In another embodiment, from 1 minute to 1 hour.
  • the volume ratio of water containing oxidants to crude oil ranges from 0.05 : 1 to 5 : 1 in one embodiment; from 1 : 1 to 2: 1 in a second embodiment; from 0.1 : 1 to 1 : 1 in a third embodiment; and at least 0.5: 1 in a fourth embodiment.
  • the amount of oxidants added can be adjusted to control the type and amount of heavy metal complexes formed. For example, in one embodiment for the removal of arsenic from a crude oil, excess oxidants can be added to for the conversion of as much of the arsenic into As 5+ as possible, e.g., at least 90%, instead of a mixture of As 3+ and As 5+ .
  • the pH of the water stream or treatment solution containing the oxidizing is adjusted to a pre-selected pH depending on the heavy metals contained in the crude oil to be treated.
  • the pre-select pH is less than 6 in one embodiment; less than 5.5 in a second embodiment; less than 4 in a third embodiment; and less than 3 in a fourth embodiment.
  • a sufficient amount of oxidant is employed to convert at least 75% of the heavy metals, e.g., elemental mercury, to mercury cations. In another embodiment, an amount is used for a conversion of at least 95%. In a third embodiment' at least 99%. In a fourth embodiment, an amount for at least 50% of heavy metals to be extracted from the crude oil. In a fifth embodiment, an amount for at least 25% of heavy metal extraction from the crude oil. In one embodiment for the removal of mercury, the oxidant generates non-complexed ionic mercury ions from elemental mercury and complexed mercury.
  • the oxidant is selected from the group of halogens, halogen oxides, molecular halogens, peroxides and mixed oxides, including oxyhalites, their acids and salts thereof.
  • the oxidant is selected from the group of peroxides (including organic peroxides) such as hydrogen peroxide (H 2 0 2) , sodium peroxide, urea peroxide, alkylperoxides, cumene hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, cyclohexanone peroxide, dicumyl peroxide.
  • the oxidant is selected from the group of inorganic peracids such as Caro's acid (H 2 S0 5 ) or salts thereof, organic peracids, such as aliphatic Ci -to C 4 -peracids and, optionally substituted, aromatic percarboxylic acids, peroxo salts, persulfates, peroxoborates, or sulphur peroxo-compounds substituted by fluorine, such as S 2 0 6 F 2 , and alkali metal peroxomonosulfate salts.
  • Suitable oxygen-containing oxidizing agents also include other active oxygen-containing compounds, for example ozone.
  • the oxidant is selected from the group of monopersulfate, alkali salts of peroxide like calcium peroxide, and peroxidases that are capable of oxidizing iodide.
  • the oxidizing agent is selected from the group of sodium perborate, potassium perborate, potassium peroxymonosulfate, sodium peroxocarbonate, sodium peroxodicarbonate, and mixtures thereof.
  • the oxidizing agent is hydrogen peroxide in the form of an aqueous solution containing 1 % to 60 % hydrogen peroxide (which can be subsequently diluted as needed).
  • the oxidizing agent is H 2 0 2 in the form of a stable aqueous solution having a concentration of 16 to 50 %.
  • the oxidizing agent H 2 0 2 is used as a solution of 1 - 3 % concentration.
  • the oxidant selected is a hypochlorite, e.g., sodium
  • hypochlorite which is commercially produced in significant quantities.
  • the hypochlorite solution in one embodiment is acidic with a pH value of less 4 for at least 80% removal of mercury. In another embodiment, the solution has a pH between 2 and 3. In a third
  • the sodium hypochlorite solution has a pH of less than 2.
  • a low pH favors the decomposition to produce OC1 " ions.
  • the oxidant is selected from the group of elemental halogens or halogen containing compounds, e.g., chlorine, iodine, fluorine or bromine, alkali metal salts of halogens, e.g., halides, chlorine dioxide, etc.
  • the compound is an iodide of a heavy metal cation.
  • the oxidant is selected from ammonium iodide, an alkaline metal iodide, and etheylenediamine dihydroiodide.
  • the oxidant is selected from the group of hypochlorite ions (OCl ⁇ such as NaOCl, NaOCl 2 , NaOCl 3 , NaOCL,, Ca(OCl) 2 , NaC10 3 , NaC10 2 , etc.), vanadium oxytrichloride, Fenton's reagent, hypobromite ions, chlorine dioxine, iodate I0 3 " (such as potassium iodate KI0 3 and sodium iodate NaI0 3 ), and mixtures thereof.
  • the oxidant is selected from KMn0 4 , K 2 S 2 0 8 , K 2 Cr0 7 , and Cl 2 .
  • iodine is employed as the oxidizing agent.
  • 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.
  • the iodide is selected from ammonium iodide, alkali metal iodide, an alkaline earth metal iodide, and etheylenediamine dihydroiodide.
  • 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.
  • I 2 molecular iodine
  • Hg° metallic mercury
  • Hg 2+ mercury ions
  • the water soluble complexes 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 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 10: 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 2 ⁇ .
  • 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.
  • Hg 2 I 2 (solid) + I 2 (solution) 2HgI 2 (solution) -> 2Hg 2+ (aq) + 4I " (aq).
  • I 2 oxidizes the solids to form Hg 2+ and elemental S or SO 4 2" .
  • the reactions proceed very fast at room temperature (e.g., 25°C), and even faster at elevated temperatures.
  • the separation of the water and oil phases to remove the heavy metal cations happens with the use of separation devices, e.g., mechanical / rotating means such as a centrifuge or a hydrocyclone, for a long period of time, e.g., more than 10 minutes or 20 minutes, etc.
  • separation devices e.g., mechanical / rotating means such as a centrifuge or a hydrocyclone
  • the removal of heavy metals can be enhanced with the addition of a complexing agent to the oil-water emulsion mixture, thus alleviating the need for an oil-water separation device, e.g., a device using mechanical or rotating means.
  • Heavy metals such as arsenic, mercury, and the like form coordination complexes with compounds including but not limited to oxygen, sulfur, phosphorous and nitrogen-containing compounds.
  • the complexing agent forms strong complexes with the heavy metal cations, e.g., Hg 2+ , As 3+ or As 5+ , extracting heavy metal complexes from the oil phase and / or the interface phase of the oil-water emulsion into the water phase by forming water soluble complexes.
  • the addition of a complexing agent essentially eliminates or reduces the volume of the oil- water emulsion layer, and replaces the emulsion layer with separate oil and water layers.
  • the addition of the complexing agent can occur either before, simultaneously with, or after the addition of the oxidizing agent to the crude oil.
  • Different complexing agents can be added at the same time, or in succession, for the extraction of different heavy metal cations into the water phase.
  • an inorganic sulfur compound such as sodium polysulfide is employed as the complexing agent for the extraction of As 3+ into the water phase
  • a transition metal halide such as ferric chloride or zinc chloride is employed for the extraction of As 5+ into the water phase.
  • the formation of a water layer containing heavy metal cations occurs within 15 minutes after the addition of the complexing agent.
  • a separate water layer is formed after 10 minutes.
  • the formation of a water layer containing soluble heavy metal cations occurs within 20 minutes of the addition of the oxidizing agent to the crude oil.
  • the formation of a water layer occurs within 15 minutes of the addition of the oxidizing agent to the crude oil.
  • the formation is within 5 minutes.
  • the complexing agents are employed in an amount sufficient to effectively stabilize (form complexes with) the soluble heavy metals in the oil-water mixture.
  • the sufficient amount is expressed as molar ratio of complexing agent to soluble mercury in the ranges of 1 : 1 to 5,000: 1.
  • 4 embodiment from 20: 1 to 500: 1.
  • a selective complexing agent has a large equilibrium binding constant for non-complexed mercury or arsenic ions and is resistant to oxidation by the oxidizing agent added to the oil-water emulsion layer (if it can be isolated), or the crude oil / oxidizing agent mixture.
  • the addition of the complexing agent allows at least 50% of the cations to react with the complexing agent, forming a water-soluble compound, e.g., mercury or arsenic complexes, when it comes into contact with the heavy metal ions.
  • at least 75% of the heavy metal ions in the oil phase and / or interface phase are converted into water-soluble complexes.
  • At least 90% conversion into water-soluble complexes at least 90% conversion into water-soluble complexes.
  • at least 95% of the heavy metal ions are converted / extracted from the oil phase and / or interface phase into the water phase as water-soluble compounds.
  • a complexing agent which also functions as a reducing agent, it neutralizes excess oxidant that could make the crude oil corrosive.
  • Examples of chelating groups that are selective toward mercury and / or arsenic include thiol groups, dithiocarbamic acid, thiocarbamic acid, thiocarbazone, cryptate, thiophene groups, thioether groups, thiazole groups, thiourenium groups, amino groups, polyethyleneimine groups, N-thiocarbamoyl-polyalkylene polyamino groups, derivatives thereof, and mixtures thereof.
  • complexing agents as reducing agents include but are not limited to sodium metabisulfite (Na 2 S 2 0 5 ), sodium thiosulfate (Na 2 S 2 0 3 ) and thiourea.
  • the complexing agent is an inorganic sulfur compound selected from the group of sulfides, thiosulfates and dithionites. Examples include but are not limited to ammonium thiosulfate, alkali metal thiosulfates, alkaline earth metal thiosulfates, iron thiosulfates, alkali metal dithionites, and alkaline earth metal dithionites, and mixtures thereof.
  • sulfides include but are not limited to potassium sulfide, sodium sulfide, alkaline earth metal sulfides, sulfides of transition elements number 25-30, aluminum sulfides, cadmium sulfides, antimony sulfides, Group IV sulfides, and mixtures thereof.
  • Suitable alkali metal thiosulfate includes 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 particularly suitable as an alkaline earth metal dithionite complexing agent for the removal of arsenic and mercury.
  • 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 forming effect of the polyamine.
  • the complexing agent is tetraethylenepentamme (TETREN), which forms a stable complex with mercury at a pH around 4.
  • the complexing agent is selected from the group of DEDCA (diethyl dithiocarbanic acid) in a concentration of 0.1 to 0.5M, DMPS (sodium 2,3- dimercaptopropane-1 -sulfonate), DMSA (meso-2, 3-dimercaptosucccinic acid), BAL (2,3- dimercapto-propanol), CDTA (1,2-cyclohexylene-dinitrilo-tetraacetic acid), DTPA (diethylene triamine pentaacetic acid), NAC (N-acetyl L-cystiene), sodium 4,5-dihydroxybenzene-l,3- disulfonate, polyaspartates; hydroxyaminocarboxylic acid (HACA); hydroxyethyliminodiacetic (HEIDA); iminodisuccinic acid (IDS); nitrilotriacetic acid (NTA), aminopolycarboxylic acid (DEDCA), amino
  • hydroxyethylethylenediaminotriacetate hydroxyethylethylenediaminotriacetate
  • oxycarboxylic acids citrate, tartrate, gluconate
  • other carboxylic acids and their salt forms phosphonates, acrylates, and acrylamides, and mixtures thereof.
  • the complexing agent is a metal halide, for example, halides selected from the group Li, Na, K, Ca, Ni, Fe, Zn, Ba, Sr, Ag and combinations thereof.
  • the complexing agent is selected from nickel and ferric ions, e.g., salts such as FeCl 3 or NiCl 2 , forming compounds encompassing the heavy metal ions, e.g., ferric arsenate and ferric hydroxide.
  • Another example of a complexing agent is KI, which combines with mercuric iodide to form a water soluble compound having the formula K 2 HgI 4 .
  • inorganic sulfur compounds as complexing agents, a sufficient amount of inorganic sulfur compounds is employed that correlates to the solubility of the inorganic sulfur compounds in water.
  • complexing agents which are relatively soluble in water include alkali metal sulfides, nitrogen sulfides, alkali metal thiosulfates, ammonium thiosulfate, alkaline earth metal thiosulfates, iron thiosulfate, and alkali metal dithionites.
  • Less soluble inorganic sulfur compounds include alkaline earth metal sulfides, transition metal sulfides of elements 25 to 30, and Group IV sulfides.
  • the sufficient amount ranges from 5: 1 to 1,000: 1 as molar ratio of the inorganic sulfur compound to heavy metals in the crude oil.
  • the complexing agent is selected from the group of metal halides (particularly for As 5+ conversion) and sulfide compounds (particularly for As 3+ conversion).
  • the metal halides are selected from halides of Fe, Cu, Co, Zn, Sr, Ag, which oxidize arsenic species (e.g., arsenate) to form water soluble complexes such as FeHAs0 4 + , CoHAs0 4 °, ZnHAs0 4 °, SrH 2 As0 4 + , and Ag 2 H 2 As0 4 + .
  • inorganic sulfide compounds include but are not limited to sodium polysulfide, sodium thiosulfate, potassium peroxomonosulfate, and mixtures thereof.
  • an acidic complexing agent is employed with the addition of an acid such as HC1, for the complexing agent to have a pH of 5.5 or less in one embodiment, 5 or less in a second embodiment, and 3 or less in a third embodiment.
  • an acid such as HC1
  • a solution mixture of KI and HC1 having a pH in the range of 1.5 to 3 is employed.
  • a solution mixture of KBr and HC1 having a pH of less than 4 is used.
  • an HCl-thiourea solution mixture is used, with the acid concentration of less than 5M and thioureas concentration from 0.3 to 1.4M.
  • an acid is added to the crude oil / water mixture to adjust the pH to an acidic level of 5.5 or less.
  • the pH adjustment can be done prior to the addition of the oxidizing agent, simultaneously with the addition of the oxidizing agent, prior to the addition of the complexing agent, or simultaneously with the addition of the complexing agent.
  • the pH adjustment is after the addition of the oxidizing agent and prior to the addition of the complexing agent.
  • the acid for the pH adjustment can be any mineral acid known in the art.
  • At least a demulsifier is added to the mixture to further chemically separate the crude oil and the water containing the heavy metal compounds.
  • at least a demulsifier is added at a concentration from 100 to 5,000 ppm.
  • a demulsifier is added at a concentration from 100 to 1,500 ppm.
  • the demulsifier is added along with pH adjustment with caustic or acid.
  • surfactants are sometimes required for resolution of solids, viscous oil-water interfaces and sludging if any.
  • the demulsifier is a commercially available demulsifier selected from polyamines, polyamidoamines, polyimines, condensates of o-toluidine and formaldehyde, quaternary ammonium compounds and ionic surfactants.
  • the demulsifier is selected from the group of polyoxyethylene alkyl phenols, their sulphonates and sodium sulphonates thereof.
  • the demulsifier is a polynuclear, aromatic sulfonic acid additive.
  • the trace amount removal rate depends on the type of heavy metal to be removed, the oxidant and complexing reagents employed, and in one embodiment, the pH of the reagents.
  • an oxidant is first prepared or obtained. The oxidant is brought in contact with the crude oil containing heavy metals by means known in the art.
  • at least a complexing agent is added to the crude oil-oxidant mixture, forming soluble metal complexes, thus extracting the heavy metal complexes into the aqueous phase.
  • the pH of the solution can first be adjusted or maintained by the use of a buffer to improve the removal rate.
  • exemplary buffers such as phosphate and citrate, are serviceable for a prescribed pH range.
  • the pH can be adjusted to the alkaline range using ammonium hydroxide, ammonium chloride, ammonium citrate, ammonium lactate, potassium hydroxide, potassium formate, sodium hydroxide, sodium acetate, and mixtures thereof.
  • nitriloacetic acids can be used as buffers.
  • the pH can be adjusted to the acidic range using acids such as HC1. Other exemplary acids include phosphoric acid and acetic acid.
  • the pH of the solution is maintained in a neutral range of 6-8.
  • the pH of the solution is kept acidic at a pH of less than 3.
  • the contact between the crude oil and the reagents can be at any temperature that is sufficiently high enough for the crude oil to be completely liquid.
  • the contact is at room temperature.
  • the contact is at a sufficiently elevated temperature, e.g., at least 50°C.
  • the process is carried out about 20°C to 65°C.
  • the contact time between the reagents and the crude oil is for a sufficient amount of time for a portion of the heavy metals to be extracted from the crude oil into the water-oil emulsion, and subsequently into the water phase.
  • the contact time is sufficient for at least 50% of the heavy metals to be extracted from the crude oil into the water phase.
  • at least 75% extraction In a third embodiment, at least 90% extraction.
  • the sufficient amount of time is dependent on the mixing of the crude oil with the reagents. If vigorous mixing is provided, the contact time can be as little as 20 seconds.
  • the contact time is at least 5 minutes. In another embodiment, the contact time is at least 30 minutes.
  • the contact is continuous for at least 2 hrs.
  • the oxidant and complexing reagents can be introduced continuously, e.g., in a water stream being brought into contact continuously with a crude oil stream, or intermittently, e.g., injection of a water stream batch-wise into operating gas or fluid pipelines. Alternatively, batch introduction is effective for offline pipelines.
  • the oxidant and complexing reagents are added to the crude oil in one single step, as separate compositions or as a single composition, for the oxidation of elemental dissolved heavy metals to be immediately followed by or almost simultaneously with the extraction of the oxidized heavy metals, e.g., Hg 2+ , into the water phase.
  • the oxidized heavy metals e.g., Hg 2+
  • the reagents are injected into the crude oil / water stream to form highly soluble mercury or arsenic complexes in the water phase, and away from the crude oil.
  • the water containing the complexes is separated from the crude oil in a phase separation device known in the art, resulting in a crude oil with a significantly reduced level of heavy metals.
  • the soluble heavy metal complexes can be isolated / extracted out of the effluent and subsequently disposed.
  • the water phase after separation can be injected back into the reservoir for water flooring, or reservoir pressure support as a mean of disposing the mercury that was originally in the crude oil.
  • the water phase is disposed into or injected back to the reservoir which produced the crude oil.
  • a complexing agent instead of or in addition to the addition of at least a complexing agent, other means are employed to enhance the resolution of the water-oil emulsions, including but not limited to heating the crude oil mixture to over 5 OX, and up to 85X, adding further mixing time, further quiescent time (8 to 24 hours), adjusting pH of the oil- water emulsion, or adding at least a demulsifier.
  • a continuous electrostatic dehydrator is used to help with the water / oil separation.
  • resolution of the water-oil emulsions is enhanced with the aid of ionic liquids and / or microwave treatment.
  • the contact between the crude oil and the oxidizing agent / complexing agent can be either via a non-dispersive or dispersive method.
  • the dispersive contacting method can be via mixing valves, static mixers or mixing tanks or vessels.
  • the non- dispersive method is via either packed inert particle beds or fiber film contactors.
  • the heavy metal removal 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 crude oil and the oxidizing agent / complexing agent, which contact zone 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. 3,997,829; 3,992,156; and 4,753,722.
  • the separation zone can be at least a separation device selected from settling tanks or drums, coalescers, electrostatic precipitators, or other similar devices.
  • the heavy metal removal treatment is via an integrated unit, e.g., a single vessel having a contact zone for crude containing heavy metals to be in intimate contact with the oxidizing agent (and / or complexing agent), and a settling zone for the separation of the treated crude from water phase containing soluble heavy metal complexes.
  • the oxidizing agent 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 oxidizing agent and the crude oil in the unit can be counter-current or concurrent.
  • the heavy metal removal is via a single tower with a top section for the mixing of the crude oil with the oxidizing agent / complexing agent and a bottom section for the separation of the treated crude from the water phase.
  • 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 would 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 oxidizing agent to form a thin film on the surface of fibers, and present a large surface area to the crude oil to be treated.
  • the admixture of the treated crude oil and the oxidizing agent exits the bottom of the first contactor and flows into the next contactor in series, wherein the complexing agent is introduced.
  • the admixture with the addition of the complexing agent exits the bottom contactor and is directed to a bottom separation section.
  • the oxidizing agent feed and / or complexing agent feed can be split and added to any of the contactors in series for the treatment of the crude.
  • crude oil feed may be split with additional crude being injected into any of the contactors in series for enhanced surface contact between the crude and the oxidizing agent, while oxidizing agent feed flows through the fibers from one contactor to the next one in series.
  • the treated crude is allowed to separate from the aqueous phase containing the extracted heavy metals via gravity settling.
  • the bottom section also comprises fibers to aid with the separation, wherein the mixture of treated crude oil and the aqueous phase flows through the fibers to form two distinct liquid layers, an upper layer of treated crude and a lower aqueous phase layer containing oxidized heavy metals.
  • the heavy metal removal is carried out in an integrated unit having multiple sections, e.g., an extractor section for oxidizing the heavy metals in crude oil upon contact with the oxidizing agent; a pre -mixing section for the preparation of a complexing agent to be added to the admixture of crude oil and oxidizing agent, 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 aqueous phase containing extracted heavy metals.
  • an extractor section for oxidizing the heavy metals in crude oil upon contact with the oxidizing agent
  • a pre -mixing section for the preparation of a complexing agent to be added to the admixture of crude oil and oxidizing agent, 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 aqueous phase containing extracted heavy metals.
  • the heavy metal complexes are removed from water through the use of a selective adsorbent material, e.g., a porous resin having mercury selective chelating groups bound thereto.
  • a selective adsorbent material e.g., a porous resin having mercury selective chelating groups bound thereto.
  • the heavy metal complexes are subsequently removed through techniques such as filtration, coagulation, flotation, co-precipitation, ion exchange, reverse osmosis, ultra-filtration using membranes and other treatment processes known in the art.
  • the crude oil feed can have an initial heavy metal level such as mercury 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 of heavy metals such as mercury.
  • the heavy metal level in the crude oil 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 is removed. In a seventh embodiment, the removal or the reduction is at least 90%.
  • Heavy metal levels e.g., mercury or arsenic
  • CV-AAS cold vapor atomic absorption spectroscopy
  • CV-AFS cold vapor atomic fluorescence spectroscopy
  • Examples 1 - 11 A series of experiments are carried out, each for a different oxidant.
  • Example 1 is a control experiment without any oxidant being used (complexing agent TETREN only at a final concentration of 30 ⁇ ).
  • TETREN complexing agent
  • Example 1 5mL of mercury vapor feed was placed into a lOmL Teflon-capped centrifuge tube. Oxidant was added to make a final concentration as shown in Table 1. The tube was shaken vigorously for about 2 minutes. 5 mL of distilled water was added to tube. A pre-determined volume of TETREN was added for a final concentration of 30 ⁇ . Tube was again shaken by hand vigorously for about 2 minutes, then centrifuged for 1 minute to separate oil from water. Aliquots of the oil and water were measured for Hg using a Lumex Hg analyzer equipped with Pyro-915+. Results of the experiments are shown in Table 1.
  • Examples 12 - 14 The same procedures in Examples 1-11 are repeated, but with OxoneTM (2KHS0 5 .KHS0 4 .K 2 S0 4 ) as the oxidant at different dosage levels, and with different complexing agents (or none) as indicated in Table 2. The results are listed in Table 2.
  • Examples 15- 25 The same procedures were repeated but with different oxidants at different concentrations as shown in the table, and with TETREN as the complexing agent added for a final concentration at 1,500 ppm. Results are shown in Table 3:
  • Examples 26 - 50 The same procedures in Examples 2-11 are repeated, but with different oxidants at different dosage levels, as well as different complexing agents at different final concentrations. Results are as indicated in Table 4.
  • Examples 51-53 50 mL of mercury vapor feed preparation containing approximately 1,100 ppb Hg was added to a number of 100 mL glass tubes, then mercury level was measured using LUMEX mercury analyzer equipped with PYRO-915+. 50 mL of distilled water was placed in the tubes, and the mercury level was measured using LUMEX mercury analyzer equipped with PYRO-915+. A pre-determined volume of 3 different oxidants (hydrogen peroxide (H 2 0 2 ), t-butyl hydroperoxide, and cumene hydroperoxide) was added to each reactor for a final oxidant concentration of 50 ppm. The oil-water mixture was stirred up for 1 minute.
  • H 2 0 2 hydrogen peroxide
  • t-butyl hydroperoxide t-butyl hydroperoxide
  • cumene hydroperoxide cumene hydroperoxide
  • Example 54 50 mL of mercury vapor feed preparation (i.e., mineral oil) containing approximately 1,100 ppb Hg is added to a number of 100 mL glass tubes, then mercury level is measured using LUMEX mercury analyzer equipped with PYRO-915+.
  • mercury level is measured using LUMEX mercury analyzer equipped with PYRO-915+.
  • Four different samples of pre-determined volume of 5 mmol/L sodium chlorite at different pH (3, 6, 9, and 11) is added to each tube for a final oxidant concentration of 50 ppm.
  • the pH of the sodium chlorite solution is adjusted by the addition of HC1.
  • the mixture is stirred up for at least 10 minutes. It is expected that high pH values weakens the rate of Hg° oxidation, e.g., from greater than 80% mercury removal at a pH of 3 to less than 10% at a pH of 11.
  • Example 55 50 mL of crude oil containing approximately 1,000 ppb Hg was added to a 100 mL glass tube, then mercury level was measured using LUMEX mercury analyzer equipped with PYRO-915+. A pre-determined volume of 5 wt.% sodium hypochlorite solution was added to the glass tube for a final oxidant concentration of 50 ppm. The mixture was stirred for at least 10 minutes. A cloudy oil-water emulsion was formed in the test tube, indicating that oxidation took place but it would be difficult to separate the emulsion from the crude oil.
  • Example 56 50 mL of crude oil containing approximately 1,000 ppb Hg is added to a 100 mL glass tube, then mercury level is measured using LUMEX mercury analyzer equipped with PYRO-915+. A pre-determined volume of 5 wt. % aqueous solution of FeCl 2 is added to the glass tube for a final concentration of 50 ppm. It is expected that oxidation is to take place, but the mercury cations will remain trapped in a cloudy oil-water emulsion and that it will be difficult to separate the emulsion layer from the crude oil.
  • Example 57 Example 56 is repeated, except that a complexing agent, e.g., KI solution at different pH (7, 5, and 3) is added to the oil- water emulsion, and the mixture is stirred up for at least 10 minutes.
  • a complexing agent e.g., KI solution at different pH (7, 5, and 3)
  • the acidic KI enhances the mercury removal with the formation of soluble mercury compounds which minimizes the volume of the emulsion, resulting in separate water / crude oil layers with reduced mercury level of at least 50% in the treated crude oil, or for at least 50% of the mercuric compounds to be removed from the emulsion into the water phase.
  • an acidic pH of 3 or less allows at least 80% of the mercuric compounds from the interface layer into the water layer.
  • Example 58 50 mL of mercury vapor feed preparation containing approximately 1,100 ppb Hg is added to a number of 100 mL glass tubes, then mercury level is measured using LUMEX mercury analyzer equipped with PYRO-915+. A pre-determined volume of hydrogen peroxide (H 2 0 2 ) is added to each tube for a final oxidant concentration of 50 ppm. The oil- water mixture is stirred up for 1 minute. Thiourea is added to 200 cm 3 of HC1 2M to produce a concentration of 110 g/1. The mixture is added to the glass tube and stirred up for at least 60 minutes. Mercury extraction into the water phase is expected to be as comparable to using KI as a complexing agent, of up to 99 %, with the advantage that thioureas as a complexing agent is more economical than KI.
  • H 2 0 2 hydrogen peroxide
  • Example 59 To four glass bottles, the following is added: 1) a control sample of 40 g crude oil containing approximately 20,000 ppb Hg, 2) 40 g crude oil and 40 g deionized water, 3) 40 g crude oil and 40 g of 5.6-6.0 % sodium hypochlorite (bleach) solution; 4) 40 g crude oil and 40 g of 5.6-6.0 % sodium hypochlorite (bleach) solution.
  • the samples are shaken for 2 minutes, forming oil-water emulsion in samples 2 - 4. Samples 1 - 3 are centrifuged at 90°C and 3500 RPM for 20 minutes, effecting a water - oil separation.
  • Sample 4 is not centrifuged and left as is - still showing oil-water emulsion even after 20 minutes.
  • the oil and water phases from the samples 1- 3 are analyzed for mercury. It is expected that samples 1 - 2 show no mercury removal with the mercury still remaining in the crude oil. Sample 3 (using centrifuge to facilitate oil water separation) is expected to show a mercury removal rate of at least 70%. Sample 4 cannot be easily analyzed due to the oil-water emulsion.
  • Example 60 Sample 4 with oil-water emulsion is stirred up for 1 minute.
  • Potassium iodide KI
  • KI Potassium iodide
  • the glass bottle is shaken vigorously for 1 minute. Aliquots of both oil and water are analyzed for mercury. The sample is expected to show a mercury removal rate of at least 70% (as with sample 3), and without the need for centrifuge.
  • Example 61 To two 100 mL glass reactors, the following were added: a) 70 mL of crude oil containing approximately 5,000 ppb Hg and 30 mL of distilled water were added, then mercury levels in both crude oil and water samples were measured using a LUMEX mercury analyzer equipped with PYRO-915+; b) a pre-determined volume of oxidant 1% w/v gold chloride (HAuCl3.H 2 0) for a final oxidant concentration of HAuCl3.H 2 0 to mercury Hg of 20 and 50 respectively (on a mole basis). The agitators were stirred for about 4 minutes at 600 rpm.
  • Example 62 70mL of crude oil containing 130 ppb arsenic and 30 mL of produced water were added into a Waring blender. The initial arsenic concentrations in crude oil and produced water were measured by ICP-MS. A pre-determined volume of 10%> iodine (I 2 ) was added to oil-water mixture for a final oxidant concentration of 26 and 2 ppm respectively. The blender was started for 4 minutes. A pre-determined volume of 30% sodium thiosulfate was added to the blender cup for a final concentration complexing agent of 350 ppm. The blender was started again for 15 minutes. The oil-water mixture was poured into a glass container and kept at 60°C for 30 minutes prior to analysis. Test results showed at least 30 - 40% of arsenic was extracted from crude oil to water.
  • I 2 iodine
  • Example 63 Example 62 was repeated, also with 30% sodium thiosulfate as the complexing agent but with a final concentration of 150 ppm. Test results also showed at least 30 - 40% of arsenic was extracted from crude oil to water.
  • Example 64 In a number of 100 mL glass tubes, add 50 mL of crude oil containing approximately 6,000 ppb As and 50 mL distilled water, measure arsenic level using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Add a pre-determined volume of hydrogen peroxide (H 2 O 2 ) to each tube for a final oxidant concentration of 100 ppm. Stir the oil-water mixture for at least 5 minutes. Prepare 4 complexing agent samples including FeCl 3 , AgCl, ZnCl, and SrCl 2 , each with a concentration of 1.0 N are prepared. Adjust the pH of the complexing agent samples to about 4 by the addition of an acid such as HC1. Add the samples to 4 of the glass tubes and stir each for at least 60 minutes. It is expected that at up to 99% of the arsenic is removed from the crude oil and extracted into the water phase.
  • ICP-MS Inductively Coupled Plasma Mass Spectrometry

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PCT/US2011/061035 2010-11-19 2011-11-16 Process, method, and system for removing heavy metals from fluids WO2012068277A2 (en)

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BR112013012087A BR112013012087A2 (pt) 2010-11-19 2011-11-16 processo, método, e sistema para a remoção de metais pesados de fluidos
EP11841430.9A EP2640810B1 (de) 2010-11-19 2011-11-16 Verfahren zur entfernung von schwermetallen aus fluiden
RU2013127659/04A RU2013127659A (ru) 2010-11-19 2011-11-16 Процесс, способ и система для удаления тяжелых металлов из жидкостей
SG2013035829A SG190775A1 (en) 2010-11-19 2011-11-16 Process, method, and system for removing heavy metals from fluids
CA2818273A CA2818273A1 (en) 2010-11-19 2011-11-16 Process, method, and system for removing heavy metals from fluids
AU2011328930A AU2011328930A1 (en) 2010-11-19 2011-11-16 Process, method, and system for removing heavy metals from fluids
CN2011800589006A CN103249814A (zh) 2010-11-19 2011-11-16 从流体中脱除重金属的工艺、方法和系统

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US12/950,170 US8721873B2 (en) 2010-11-19 2010-11-19 Process, method, and system for removing heavy metals from fluids
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EP2969956A4 (de) * 2013-03-14 2016-06-22 Chevron Usa Inc Prozess, verfahren und system zur beseitigung von schwermetallen aus fluiden
CN103450930A (zh) * 2013-03-26 2013-12-18 湖南长岭石化科技开发有限公司 一种原油脱金属脱水的方法
CN103263835A (zh) * 2013-05-24 2013-08-28 上海交通大学 一种溴化铁除汞复配液及用其进行烟气除汞的方法
CN103263835B (zh) * 2013-05-24 2015-05-20 上海交通大学 一种溴化铁除汞复配液及用其进行烟气除汞的方法
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US20200172817A1 (en) * 2018-12-03 2020-06-04 Ecolab Usa Inc. Use of peroxyacids/hydrogen peroxide for removal of metal components from petroleum and hydrocarbon streams for downstream applications
WO2020117724A1 (en) * 2018-12-03 2020-06-11 Ecolab Usa Inc. Use of peroxyacids/hydrogen peroxide for removal of metal components from petroleum and hydrocarbon streams for downstream applications
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RU2691070C1 (ru) * 2018-12-27 2019-06-10 Акционерное общество "Всероссийский научно-исследовательский институт по переработке нефти" (АО "ВНИИ НП") Способ получения каталитически-сорбционного материала и способ извлечения мышьяка в его присутствии
CN113564357A (zh) * 2021-07-29 2021-10-29 南昌航空大学 一种湿法冶金用复合药剂及其制备方法和应用
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AU2011328930A1 (en) 2013-05-30
CA2818273A1 (en) 2012-05-24
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CN103249814A (zh) 2013-08-14
EP2640810B1 (de) 2016-03-02
EP2640810A2 (de) 2013-09-25
BR112013012087A2 (pt) 2016-08-16
SG190775A1 (en) 2013-07-31
WO2012068277A3 (en) 2012-09-07

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