CA1222714A - Method for removing insoluble sulfide pads at oil/water interfaces - Google Patents
Method for removing insoluble sulfide pads at oil/water interfacesInfo
- Publication number
- CA1222714A CA1222714A CA000461045A CA461045A CA1222714A CA 1222714 A CA1222714 A CA 1222714A CA 000461045 A CA000461045 A CA 000461045A CA 461045 A CA461045 A CA 461045A CA 1222714 A CA1222714 A CA 1222714A
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- CA
- Canada
- Prior art keywords
- oil
- chlorine dioxide
- sulfide
- water
- pad
- Prior art date
- Legal status (The legal status 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 status listed.)
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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
- C10G33/00—Dewatering or demulsification of hydrocarbon oils
- C10G33/04—Dewatering or demulsification of hydrocarbon oils with chemical means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
- B01D17/02—Separation of non-miscible liquids
- B01D17/04—Breaking emulsions
- B01D17/047—Breaking emulsions with separation aids
-
- 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
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Engineering & Computer Science (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
METHOD FOR REMOVING INSOLUBLE SULFIDE
AT OIL/WATER INTERFACES
Abstract of the Disclosure A method for removing insoluble metallic sulfide sludges present at oil/water interfaces by the addition of chlorine dioxide is described.
AT OIL/WATER INTERFACES
Abstract of the Disclosure A method for removing insoluble metallic sulfide sludges present at oil/water interfaces by the addition of chlorine dioxide is described.
Description
~ 27 r~
~ETHOD FOR REMOVING INSOLUBLE SULFID~
~ield of the Invention Solid metallic sulfides are frequently S encountered in petroleum processing equipment. In operations involving water and oil phase separations, such as in field dehydration systems, desalting plants, and the like, ~hese solid me~allic sulfides are p~rticularly troublesome. They have low solubility in water or brines.
The oleophilic chlracteristics of sulfides cause them to collect at the oil/water interface~ to form sludges of a complicated nature. These sludges are generally referred to as "padsnO The pads caused by the presence of the troublesome metallic sulfides drastic~lly interfere with the efficient separation of crude oil from the associated agueous medium. Under thes~ conditions, a clearly defined interface between the oil and water phases is not present due to the emulsification effect exerted by the solid metallic sulfides. As a consequence, phase separation, desalting, and similar processes required in crude oil production and refining are slowed or interrupted. The presence of -solid metallic sulfides at the oil/water interface ~orces large time, chemical, and energy expenditures to be utili~ed. This holds true for the oil phase, which must be purified before entering sefineries, as well as the aqueous phase prior to dispcsal or discharge. In addition, these metallic sulfide-containing pads create fouling of oil handling equipment~ interfere with control and sensing equipment, and produce inherent corrosion at the points of contact within oil field vessels or other metallic equipment. Such ef~ects as these add to the cost and complexity of petroleum processing. In addition, the quality and suitability of the oil for subsequent uses may be reduced by th~ occurrence of these interfacial sulfide pr~cipitates~
Prior Art In the past~ a variety of c:hemical methods have been employed in an attempt to allev.iate the problems 1~227~L~
caused by solid metallic sulfides presellt at oil/water interfaces. Earlier efforts to 801Ye this problem include the use of inorganic chloride containing chemicals such as hydrochloric acid, hypochlorous acid, alkali and alkaline earth hypochlorites, and chlorine. In addition, organic chemicals such as acrolein and various nonionic, CAtioniC~
and anionic surfactants have been employed.
Most of the inorganic chlorine-containing chemicals are required in rela~ively high concentrations and are very corrosive to the steels and other metals used in the construction of typical petroleum producing equipment. The pH's of the treated media are typically low under these conditions. The chemicals may also react with the petroleum, yielding hydroehloric acid and organic chlorides by decomposition. This alteration of the petroleum composition creates products that are poisonous to catalysts used in the refining process, which seriously affects refinery operations. Although the rate of solid metallic sulfide removal by hydrochloric acid and chlorine can be economically rapid enough, the action of hypochlorous acid and hypochlorite salts is quite slow.
Acrolein can be quite useful in removing insoluble metallic sulfides. Ho~.~ ver/ typical applications of acrolein generally require long contact periods with the pads at the oil/water interfac*. Frequently, several applications cf asrolein are required to eli.~ninate the total insoluble metallic sulfide pad. The large amounts of acrolein chemical consumed under these circumstances can become quite expensive Most applications involving nonionic, cationic, and anionic surfactants tend to remove the oil adhering to the solid metallic sulfide pad present in the oil/water interface but do not eliminate the solid metallic sulfides, so the interfacial pads reform quickly.
~hlorine dioxide has been known to successfully remove hydlogen sulfide from aqueous media for many decades. U.S. Patent 4,077,87~ discloses a process using chlorine dioxide to remove undesirable .~oluble sulfides I
-3 ~22~
fron\ aqueous systems contaminated with small amounts of petroleum oils. However, removal of oll/water interfaclal pads in bulk oil/water syst~ms by chlorine dioxide in order to improve oil recover~ has not previously been 5 k nown .
Furthermore, any use of chlorine dioxide to treat soluble metallic sulfides is limited to aqueous media. It is generally known that the ~ffects o~ solvents on chemical reaction~ can sreatly alter observati~ns.
Chlorine dioxide is not known to he effective in treating insoluble metallic sulfides in the presence of oils.
Although some chemical approache~ are available for removing metallic sulfide-contalning pads at an oil/water interface, high cost or poor performance characteristics are usually encountered~ The inventive process described hereinafter utilizes a chlorine dioxide application to treat the bulk properties of the oil/water interfacial pad caused by the solid metallic sulfides.
This process is especially useful in that it allows rapid and low cost phase separations in treatment of crude oil to remove water, solids, salts, and other impurities.
~hese steps are required beEore the petroleum can be sold, transported, and refined.
Specific references to chlorine dioxide removing insoluble iron and manganese sulfides in aqueous media can be found. However, references pertaining to other specific insoluble metals are not prominent in the literature. The inventi~e discovery of the fast action of chlorine dioxide in removing cer~ain insoluble metallic sulfide pads in oil/water interfaces present in actual oil field tanks was unpredictable from prior processes and ~uite surprising.
In practicing the inventive process for removing insoluble metallic sulfides in oil/water separation equipment, various water quality improvements may also result as a side effect of the treatment, depending upon the amount of chlorine dioxide used and its point of applicationO S~ch improv~ments may include solu~le sulfide removal, biocidal effects and others.
-4~ 2~7~
However, these benefits are ancil1ary to the inventive process, which provides oil recovery and phase ~eparation improvements regardless of whether these ancillary benefits are achieved.
ummary of_the Invention Chlorine dioxide is used in a process for eliminating the ef~ects o insoluble metalllc sulfides in impeding the separation of oils from aqueous phases encountered in petroleum processing systems~ This process involves adding aqueous chlorine dioxide solution to the oil/water mixture containing an insoluble metallic sulfide interfaciâl pad. The process results in a clearly defined oil/water interface.
Descri~tion of the Invention Insoluble metallic sulfide interfacial pads are defined âS interfacial interferences caused when metals and metallic ions combine with sulfur, hydrogen sulfide, or soluble sulfide salts to form insoluble metallic - sulfides. Examples of such metals and ions include, but ~ are not limited by, Ag, Ca, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sn, Tl, and Zn, separately or in any combined ratio.
These insoluble metallic sulfides become attracted to the oil phase of an oil/water system, and collect at the oil/water interface. Typical oils found in oil field practices combined with these insoluble m~tallic sulfide pads can experience troublesom~ interacial interferences in contact with aqueous media. This situation can also arise when dissolved gases and undissolved yases are present.
Troublesome interfacial sulfide pads can be found in oil field tank~, free-water-knockouts, heater treaters, desalters, refiner~ distillate receivers, sumps, pits, and the like. These pieces of e~uipment can be involved in constant-flowing, intermittent-flowing, and static fluid conditions Chlorine dioxide solutions can be obtained from a variety of manufacturing processes. Typical processes include acid-chlorite, acid-chlorate, acid-hypochlorous ~2;2~71~
acid-chlorite, acid-hypochlorite salts-chlorit~, chlorine~chlorite, and the like~ and any vari~tion of these systems comprised o~ process adjuvants.
The application of chlorine dioxide can be made into quiet, nonagitated petroleum processing equipment, Additionally, applications of chlorine dioxide can be accompanied by agitation of fluids within such equipment.
The temperature of the systems to which chlorine dioxide may be applied varies w~dely. The effectlveness of the inventive process is not very dependeZt on the temperature, and is found to be useful in petroleum-water separations at temperatures from low am~ient to 200C, or thereabouts. Some systems are operated under pressures to allow higher temperatures and lower fluid viscosities, which is helpful in the sedimentation and separation o~
phases. Higher temperatures appear to ]essen somewhat the amount of chlorine dioxide required.
By the use of chlorine dioxide, insoluble metal sulfides are converted to a soluble form. Presumably, the petroleum oil that wets, i.e., clings to the surface of, the insoluble metal sulfide is able, after chlorine dioxide treatment, to migrate to the petroleum oil phase and is no longer a component oE the emulsion. This then permits the clean separation of the petroleum oil from water phases. The mode of action of chlorine dioxide as described is believed to be ~orrect and ~s given for better understanding~ but is not intended to limit the scope of the invention.
Aqueous chlorine dioxide solutions c~n be added to oil/water systems in a variety of different ways in order to remove in~oluble interfacial sulfide pads. ~he chlorine dioxide may be added into the inlet lines upstream of the equipment containing the troublesome int rfacial sulide pads. Applications may also be made directly into the individual oil field eqllipn\ent. The more cost effective applications appear to be those made into the oil phase proper.
Applications of chlorine dioxide can be made -6- ` ~2~27~
into oil field vessels experiencing continuous flowing, intermittent flowing, and stagnarlt fluid conditions. The time required for complete pad removal is lessened if the ve~sel can be agitated, e.~., such as rolling tank contents with gas.
Successful applications utilize up to about three moles chlorine dioxide per mole of insoluble metallic sulfide. Th~se conditions result in lowering the pH of a given system by tWQ or less pH units for an initial system pH ran~e of A to lC for metallic substances containing chromium, iron, manganese and Yanadium. Systems comprised of cadmium, ~obalt, lead, silver, tin, and tantalum appear to require more aoidic final pH values.
Lower amounts of chlorine dioxide, and subsequently lower drops in system pH levels, are realized if the process is carried out at higher temperatures.
The invention describing a method for removing insoluble metallic sulfide pads at oil/water interfaces is demonstrated by the following non-limiting examples Ten screw cap test tubes were each filled with 1.0 mL ferric chloride solution ~0.037M) and l.OmL freshly prepared sodium sulfide solution (0.037M). ~lack iron sulfide precipitates formed immediately. These heterogeneous mixtures were diluted with 5.0 mL ASTM brine solution t4.2%, American Society Testing Materials~
formula a, A.S.T.~. D-1141-52, Table 1, section 4). These solutions gave 3.7xlO 5 moles of sulfide and had a pH of 7Ø Then, 1.0 mL Nujol (trademark) mineral oil was added, the tubes were capped, and shaken vigorously for one minute. A heavy iron sulfide pad formed at the oil/water interface in all tubes. Next, various amounts of chlorine dioxide solution (0.0266M) were added to each of the tubes and the results recorded.
`~J
7 ~3L2~27~
T~BLE 1 Moles C102 Einal Moles 5ulf.id~
added ~ H to mole~ Observations 1.33 x 10-6 7 27.8 P~d Present 51.99 x 10-6 6.6 18.~ Pad broke, but rapidly reformed
~ETHOD FOR REMOVING INSOLUBLE SULFID~
~ield of the Invention Solid metallic sulfides are frequently S encountered in petroleum processing equipment. In operations involving water and oil phase separations, such as in field dehydration systems, desalting plants, and the like, ~hese solid me~allic sulfides are p~rticularly troublesome. They have low solubility in water or brines.
The oleophilic chlracteristics of sulfides cause them to collect at the oil/water interface~ to form sludges of a complicated nature. These sludges are generally referred to as "padsnO The pads caused by the presence of the troublesome metallic sulfides drastic~lly interfere with the efficient separation of crude oil from the associated agueous medium. Under thes~ conditions, a clearly defined interface between the oil and water phases is not present due to the emulsification effect exerted by the solid metallic sulfides. As a consequence, phase separation, desalting, and similar processes required in crude oil production and refining are slowed or interrupted. The presence of -solid metallic sulfides at the oil/water interface ~orces large time, chemical, and energy expenditures to be utili~ed. This holds true for the oil phase, which must be purified before entering sefineries, as well as the aqueous phase prior to dispcsal or discharge. In addition, these metallic sulfide-containing pads create fouling of oil handling equipment~ interfere with control and sensing equipment, and produce inherent corrosion at the points of contact within oil field vessels or other metallic equipment. Such ef~ects as these add to the cost and complexity of petroleum processing. In addition, the quality and suitability of the oil for subsequent uses may be reduced by th~ occurrence of these interfacial sulfide pr~cipitates~
Prior Art In the past~ a variety of c:hemical methods have been employed in an attempt to allev.iate the problems 1~227~L~
caused by solid metallic sulfides presellt at oil/water interfaces. Earlier efforts to 801Ye this problem include the use of inorganic chloride containing chemicals such as hydrochloric acid, hypochlorous acid, alkali and alkaline earth hypochlorites, and chlorine. In addition, organic chemicals such as acrolein and various nonionic, CAtioniC~
and anionic surfactants have been employed.
Most of the inorganic chlorine-containing chemicals are required in rela~ively high concentrations and are very corrosive to the steels and other metals used in the construction of typical petroleum producing equipment. The pH's of the treated media are typically low under these conditions. The chemicals may also react with the petroleum, yielding hydroehloric acid and organic chlorides by decomposition. This alteration of the petroleum composition creates products that are poisonous to catalysts used in the refining process, which seriously affects refinery operations. Although the rate of solid metallic sulfide removal by hydrochloric acid and chlorine can be economically rapid enough, the action of hypochlorous acid and hypochlorite salts is quite slow.
Acrolein can be quite useful in removing insoluble metallic sulfides. Ho~.~ ver/ typical applications of acrolein generally require long contact periods with the pads at the oil/water interfac*. Frequently, several applications cf asrolein are required to eli.~ninate the total insoluble metallic sulfide pad. The large amounts of acrolein chemical consumed under these circumstances can become quite expensive Most applications involving nonionic, cationic, and anionic surfactants tend to remove the oil adhering to the solid metallic sulfide pad present in the oil/water interface but do not eliminate the solid metallic sulfides, so the interfacial pads reform quickly.
~hlorine dioxide has been known to successfully remove hydlogen sulfide from aqueous media for many decades. U.S. Patent 4,077,87~ discloses a process using chlorine dioxide to remove undesirable .~oluble sulfides I
-3 ~22~
fron\ aqueous systems contaminated with small amounts of petroleum oils. However, removal of oll/water interfaclal pads in bulk oil/water syst~ms by chlorine dioxide in order to improve oil recover~ has not previously been 5 k nown .
Furthermore, any use of chlorine dioxide to treat soluble metallic sulfides is limited to aqueous media. It is generally known that the ~ffects o~ solvents on chemical reaction~ can sreatly alter observati~ns.
Chlorine dioxide is not known to he effective in treating insoluble metallic sulfides in the presence of oils.
Although some chemical approache~ are available for removing metallic sulfide-contalning pads at an oil/water interface, high cost or poor performance characteristics are usually encountered~ The inventive process described hereinafter utilizes a chlorine dioxide application to treat the bulk properties of the oil/water interfacial pad caused by the solid metallic sulfides.
This process is especially useful in that it allows rapid and low cost phase separations in treatment of crude oil to remove water, solids, salts, and other impurities.
~hese steps are required beEore the petroleum can be sold, transported, and refined.
Specific references to chlorine dioxide removing insoluble iron and manganese sulfides in aqueous media can be found. However, references pertaining to other specific insoluble metals are not prominent in the literature. The inventi~e discovery of the fast action of chlorine dioxide in removing cer~ain insoluble metallic sulfide pads in oil/water interfaces present in actual oil field tanks was unpredictable from prior processes and ~uite surprising.
In practicing the inventive process for removing insoluble metallic sulfides in oil/water separation equipment, various water quality improvements may also result as a side effect of the treatment, depending upon the amount of chlorine dioxide used and its point of applicationO S~ch improv~ments may include solu~le sulfide removal, biocidal effects and others.
-4~ 2~7~
However, these benefits are ancil1ary to the inventive process, which provides oil recovery and phase ~eparation improvements regardless of whether these ancillary benefits are achieved.
ummary of_the Invention Chlorine dioxide is used in a process for eliminating the ef~ects o insoluble metalllc sulfides in impeding the separation of oils from aqueous phases encountered in petroleum processing systems~ This process involves adding aqueous chlorine dioxide solution to the oil/water mixture containing an insoluble metallic sulfide interfaciâl pad. The process results in a clearly defined oil/water interface.
Descri~tion of the Invention Insoluble metallic sulfide interfacial pads are defined âS interfacial interferences caused when metals and metallic ions combine with sulfur, hydrogen sulfide, or soluble sulfide salts to form insoluble metallic - sulfides. Examples of such metals and ions include, but ~ are not limited by, Ag, Ca, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sn, Tl, and Zn, separately or in any combined ratio.
These insoluble metallic sulfides become attracted to the oil phase of an oil/water system, and collect at the oil/water interface. Typical oils found in oil field practices combined with these insoluble m~tallic sulfide pads can experience troublesom~ interacial interferences in contact with aqueous media. This situation can also arise when dissolved gases and undissolved yases are present.
Troublesome interfacial sulfide pads can be found in oil field tank~, free-water-knockouts, heater treaters, desalters, refiner~ distillate receivers, sumps, pits, and the like. These pieces of e~uipment can be involved in constant-flowing, intermittent-flowing, and static fluid conditions Chlorine dioxide solutions can be obtained from a variety of manufacturing processes. Typical processes include acid-chlorite, acid-chlorate, acid-hypochlorous ~2;2~71~
acid-chlorite, acid-hypochlorite salts-chlorit~, chlorine~chlorite, and the like~ and any vari~tion of these systems comprised o~ process adjuvants.
The application of chlorine dioxide can be made into quiet, nonagitated petroleum processing equipment, Additionally, applications of chlorine dioxide can be accompanied by agitation of fluids within such equipment.
The temperature of the systems to which chlorine dioxide may be applied varies w~dely. The effectlveness of the inventive process is not very dependeZt on the temperature, and is found to be useful in petroleum-water separations at temperatures from low am~ient to 200C, or thereabouts. Some systems are operated under pressures to allow higher temperatures and lower fluid viscosities, which is helpful in the sedimentation and separation o~
phases. Higher temperatures appear to ]essen somewhat the amount of chlorine dioxide required.
By the use of chlorine dioxide, insoluble metal sulfides are converted to a soluble form. Presumably, the petroleum oil that wets, i.e., clings to the surface of, the insoluble metal sulfide is able, after chlorine dioxide treatment, to migrate to the petroleum oil phase and is no longer a component oE the emulsion. This then permits the clean separation of the petroleum oil from water phases. The mode of action of chlorine dioxide as described is believed to be ~orrect and ~s given for better understanding~ but is not intended to limit the scope of the invention.
Aqueous chlorine dioxide solutions c~n be added to oil/water systems in a variety of different ways in order to remove in~oluble interfacial sulfide pads. ~he chlorine dioxide may be added into the inlet lines upstream of the equipment containing the troublesome int rfacial sulide pads. Applications may also be made directly into the individual oil field eqllipn\ent. The more cost effective applications appear to be those made into the oil phase proper.
Applications of chlorine dioxide can be made -6- ` ~2~27~
into oil field vessels experiencing continuous flowing, intermittent flowing, and stagnarlt fluid conditions. The time required for complete pad removal is lessened if the ve~sel can be agitated, e.~., such as rolling tank contents with gas.
Successful applications utilize up to about three moles chlorine dioxide per mole of insoluble metallic sulfide. Th~se conditions result in lowering the pH of a given system by tWQ or less pH units for an initial system pH ran~e of A to lC for metallic substances containing chromium, iron, manganese and Yanadium. Systems comprised of cadmium, ~obalt, lead, silver, tin, and tantalum appear to require more aoidic final pH values.
Lower amounts of chlorine dioxide, and subsequently lower drops in system pH levels, are realized if the process is carried out at higher temperatures.
The invention describing a method for removing insoluble metallic sulfide pads at oil/water interfaces is demonstrated by the following non-limiting examples Ten screw cap test tubes were each filled with 1.0 mL ferric chloride solution ~0.037M) and l.OmL freshly prepared sodium sulfide solution (0.037M). ~lack iron sulfide precipitates formed immediately. These heterogeneous mixtures were diluted with 5.0 mL ASTM brine solution t4.2%, American Society Testing Materials~
formula a, A.S.T.~. D-1141-52, Table 1, section 4). These solutions gave 3.7xlO 5 moles of sulfide and had a pH of 7Ø Then, 1.0 mL Nujol (trademark) mineral oil was added, the tubes were capped, and shaken vigorously for one minute. A heavy iron sulfide pad formed at the oil/water interface in all tubes. Next, various amounts of chlorine dioxide solution (0.0266M) were added to each of the tubes and the results recorded.
`~J
7 ~3L2~27~
T~BLE 1 Moles C102 Einal Moles 5ulf.id~
added ~ H to mole~ Observations 1.33 x 10-6 7 27.8 P~d Present 51.99 x 10-6 6.6 18.~ Pad broke, but rapidly reformed
2.39 x 10-6 6.3 15.0 Pad broke, but slowly reformed 2.66 x 10-6 6.1 13.7 Pad disappeared 102.79 x 10-6 6.0 13.3 Pad disappeared 2.92 x 10-6 5.0 12.7 Pad disappeared
3.32 x 1n~5 4.5 11~1 Pad disappeared 3.98 x 10~6 4,0 9.3 Pad disappeared 7.96 x 10-6 3.0 4.6 Pad disappeared 151.06 x 10-5 2.0 3.5 Pad dis~ppeared 2.12 x 10-5 1.0 1.7 Pad disappeared This example demonstrates the ability of chlorine dioxide to remove an iron sulfide pad in a synthetic oil/water system. It is Rlso clearly shown the pad can be removed without causing the p~ of the aqueous solution to drop by ~ore ~han 0.9 of a p~ uni~.
Three screw cap test tubes wer~ each filled with 0.5 mL ferric chloride solution (0.037M) and 0.5 mL
~reshly prepared sodium suli~e solution (0.C37M). The black iron sulfide precipitat~s were dilu~ed with 2.0 mL
deionized water and vi.gorously shaken with 9,5 mL various oils to provide a heavy pad at ~he oil/water interfaces.
Then, 3,0x10-6 moles chlorine dioxide were added. The initial pH of 6.5 fell to 6~0 after treatment with the chlorine dioxide, at a ratio of 0.62 moles o$ sulfide to 1~0 moles of chlorine dioxide~
~il Used _ Results Mineral oil Pad remoYed; did not reform 23 API California Cr~ude ~ad removed; did not re$orm 35 API Arkansas Crude Pad remo~e~; ~id not reform This e~ample dernonstrates that chlorine dioxide ~22;~
is effective in removing pads not only at the oil/water interface oi synthetic oils, but also ~t interfaces between aqueous phases and actual crude oils.
EXAMPL~ 3 Eight screw cap test tubes were charged with equal amounts of 0.037M ferric chloride and 0.037M sodium sulfide ~olutions. Then, 4.2~ ~STM brine solution and mineral oil were added. The tub~s were capped and shaken to obtain a heavy oil/water interfacial pad. These solutions had an initial pH of 7~0. Then, l.llx10 5 M
chlorine dioxide solution was added, and the observations recorded.
TABI.E 3 Moles of Ferric Chloride mL 4.2% mL Final 15 & Sodium Sulfide ASTM Brine Nu~ pH Observations 3.7 x 10 6 5.0 1.0 - No pad formed initially 1.85 x 10 5 5.5 1.0 4~0 Pad removed 3.7 x 10-5 6.0 1.0 4.0 Pad removed 203.7 x 10 6 10.0 1.0 _ No pad formed initially 3.7 x 10 5 21.0 1.0 ~.0 Pad removed 3.7 x 10 5 6.0 S.0 6.0 Pad removed 3.7 x 10 5 4~U 13.0 7.0 Pad removed 253.7 x 10 5 11.0 1~,0 7,0 Pad removed These exa~nples demonstrate the ability of chlorine dioxide to remove various amounts of interfacial pads in varying ~il to water systems~
The ability of chlorine dioxide to remove oil/water interfacial sulfide pads in systems with varying pH's can also be demonstrated. Several screw cap test tubes were charged with 1.48x10 6 moles of ferric chloride and 1.48x10 6 moles sodium sulfide. Each of these mixtures was diluted with 1.0mL various pH buffer solutions and 0.5mL mineral oil. Upon shaking, heavy interfacial pads formed. Then, 0.037M chlorine dioxide solution was added 27~
and, in all cases, the pad was removed~
Initial Moles Final ~o~ L~m æ~l ~a~
~.
Deionized System 6 9.74 x lQ 7 5
Three screw cap test tubes wer~ each filled with 0.5 mL ferric chloride solution (0.037M) and 0.5 mL
~reshly prepared sodium suli~e solution (0.C37M). The black iron sulfide precipitat~s were dilu~ed with 2.0 mL
deionized water and vi.gorously shaken with 9,5 mL various oils to provide a heavy pad at ~he oil/water interfaces.
Then, 3,0x10-6 moles chlorine dioxide were added. The initial pH of 6.5 fell to 6~0 after treatment with the chlorine dioxide, at a ratio of 0.62 moles o$ sulfide to 1~0 moles of chlorine dioxide~
~il Used _ Results Mineral oil Pad remoYed; did not reform 23 API California Cr~ude ~ad removed; did not re$orm 35 API Arkansas Crude Pad remo~e~; ~id not reform This e~ample dernonstrates that chlorine dioxide ~22;~
is effective in removing pads not only at the oil/water interface oi synthetic oils, but also ~t interfaces between aqueous phases and actual crude oils.
EXAMPL~ 3 Eight screw cap test tubes were charged with equal amounts of 0.037M ferric chloride and 0.037M sodium sulfide ~olutions. Then, 4.2~ ~STM brine solution and mineral oil were added. The tub~s were capped and shaken to obtain a heavy oil/water interfacial pad. These solutions had an initial pH of 7~0. Then, l.llx10 5 M
chlorine dioxide solution was added, and the observations recorded.
TABI.E 3 Moles of Ferric Chloride mL 4.2% mL Final 15 & Sodium Sulfide ASTM Brine Nu~ pH Observations 3.7 x 10 6 5.0 1.0 - No pad formed initially 1.85 x 10 5 5.5 1.0 4~0 Pad removed 3.7 x 10-5 6.0 1.0 4.0 Pad removed 203.7 x 10 6 10.0 1.0 _ No pad formed initially 3.7 x 10 5 21.0 1.0 ~.0 Pad removed 3.7 x 10 5 6.0 S.0 6.0 Pad removed 3.7 x 10 5 4~U 13.0 7.0 Pad removed 253.7 x 10 5 11.0 1~,0 7,0 Pad removed These exa~nples demonstrate the ability of chlorine dioxide to remove various amounts of interfacial pads in varying ~il to water systems~
The ability of chlorine dioxide to remove oil/water interfacial sulfide pads in systems with varying pH's can also be demonstrated. Several screw cap test tubes were charged with 1.48x10 6 moles of ferric chloride and 1.48x10 6 moles sodium sulfide. Each of these mixtures was diluted with 1.0mL various pH buffer solutions and 0.5mL mineral oil. Upon shaking, heavy interfacial pads formed. Then, 0.037M chlorine dioxide solution was added 27~
and, in all cases, the pad was removed~
Initial Moles Final ~o~ L~m æ~l ~a~
~.
Deionized System 6 9.74 x lQ 7 5
4.2% ASTM brine 5 9.74 x 10 7 5 Phthalate 4 9.74 x 10 7 4 Phthalate 5 9.74 x 10 7 S
Acetate 5.5 9.74 x 10~7 5.5 Phosphate/Citrate 6.5 1.95 x 1~ 6 6 Phosphate 6 2.9~ x lQ 6 Phosphate 7 3~9 x 10 ~ 6 Tris 6.5 9~74 x 10--7 5.5 Phosphate ~ ~.87 x 10 6 7 Tris 8.5 5.84 x 10 6 7 Borate 8 3.8~ x 10 6 7 Borate 8.S 4~85 x 10 6 8 Tris 9 6.01 x 10 ~ 8.5 ~orate 10 6.Ul x 10-6 8 Carbona~e 10 4.~7 x 10 6 8 Chlorine dioxide can remove oil/water interfacial sulfide pads under a wide variety of temperatures. Several screw cap test tubes were charged with l.OmL ferric chloride (0.037M~ and l~O~IL freshly prepared sodium sulfide (0.037M). The re.sulting mixtures were diluted with 5.0mL of aqueous medium and l.OmL
mineral oil. Upon vigorous shaking, heavy sulfide interfacial pads formed. Then, the tubes were heated to various temperatures. Chlorine dioxide solution was then added at the elevated temperature and r in all cases, the sulfide interfacial pad was removed.
Initial Temperature Moles Final Medium pH _ (~C~
4.2% AST~ 7 21 7.~ x 10 6 6 4.2% ASTM 7 35 5~57 x 10 6 7 4.2% ASTM 7 4b 5.13 x 10 6 7 !
~2~7~.~
--10`-Initial Temperature Moles FinalMedium ~ (C) _ _C~ E~
4.2~ ASTM 7 554.46 x 10 6 7 4.2% ASTM 7 644.23 x 10 6 7 54.2~ ASTM 7 804.12 x 10 6 7 4.2% ASTM 7 964.12 x 10 6 7 0.42~ ASTM 7 211.0 x 10 5 4 O . 42% ASTM 7 4~8 . 91 x 10 5 5 0.42% ASTM 7 558.36 x 10 6 5 lQ0.42~ ASTM 7 708.36 x 10 6 5 n . 42~ ASTM 7 947.8 x 10 ~ 5.5 Phosphate ~uffer 6 ~1 1.78 x 10 5 4 Phosphate Buffer 6 40 1.73 x 10 5 5 Phosphate Buffer 6 55 1.67 x 10 5 6 Phosphate Buffer 6 66 1.67 x 10 5 6 Phosphate Buffer 6 90 1~67 x 10 5 6 Tris Buffer 7 216.13 x 10 6 6,5 Tris Buffer 7 425,5 ~ 10-6 7 Tris Buffer 7 535.5 x 10 6 7 Tris Ruffer 7 645.35 x 10 6 7 Tris Buffer 7 885.35 x 10 6 7 ~orate Buffer 8 211.39 x 10 5 5 Borate huffer ~ 371.23 x 10 5 5.5 Borate Buffer 8 501.11 x 10 5 6 Borate Buffer ~ 701~11 x 10 5 6 Borate ~uffer 8 341.~ x 10 5 6 These results demonstrate the effect of higher temperature on the ability o~ chlorine dioxide to remove interfacial ~ulfide pads. Adding heat to the oil/water system allows less chlorine dioxid~ to be used to accomplish pad removal. This decrease in the amount o~
chlorine dioxide produces an aqueous system with a higher pH.
Agitation of the oil/water system can greatly decrease the time required for a given amount of chlorine dioxide to remove an interfacial sulfjde pad. Two 250mL
flasks were charged with 5,0~L each of ferric chloride ~2~714 ~0.037M) and ~odium sulfide (0.037M) solutions. These mixtures were then diluted with 100ml ASTM brine ~4.2~
and 50ml mineral oil. These sy~tems were shaken tn create a heavy interfacial sulfide p~d. Then, 8.1 x 10-6 moles of chlorine dioxide solution was added to the top portion of one flask without agitation. Six minute~ were required to completely remove the pad under the undis~urbed conditions.
Again, 8.1x10 6 moles chlorine dioxide was added to top portion of the other flask. A magnetic stirring bar was used to create a minor agitation condition at a spinning rate of 20 cps. Under these conditions, the pad disappeared in 30 seconds.
EXA~PLE 7 Chlorine dioxide can be used to remove oil/water interfacial sulfide pads containing metals other than iron Several screw cap test tubes were charged with a soluble metallic salt and an equimolar amount of freshly prepared sodium ~ulfide solution. These mixtures were diluted with 4.2% ASTM bri.ne and mineral oil. Then, chlorine dioxide solution was added which caused removal of the interfacial sulfide pad in all casefi. The data are ~isplayed below.
Metal Moles mL ASTM mL Init.ial Moles Final Salt Sulfide Brine Oil _ pH ~ Z____ __E~L
MnCl~ 3.7x10 5 7 1 7 2.655 x 10 6 6.9 CrC13 3.7x10-5 7 1 7 l.~6 x 10-6 6.9 VC13 3.7x10-5 8 1 7 2.655 x 10-6 6 MnC12 3.7x10 5 12 1 8 2.78 x 10 5 8 MnC12 3.7x10-5 5 10 8 2 23 x 10 5 8 MnC12 3.7x10 5 7 15 ~ 2.23 x 10 5 8 CdC13 3.7x10-5 7 1 7 3.1 x 10-5 CoC12 3.7x10-5 7 1 7 5.31 x 10-4 Pb(OAc)2 3.7x10 5 7 1 7 1.06 x 10 3 AgNO3 3.7x10-5 7 1 7 5.31 x 10 4 SnCl~ 3.7x10-5 7 1 7 1.06 x 10-3 Tl(OAc) 3.7x10 5 7 1 7 1.33 x 10 4 ~2Z7~4 Metal Moles mL ASTM mL Initial Moles Final Salt Sulfide _ ine oil pH
Complex Mixture:
FeCl3 1.85xlO 5 110 50 7 ~.1 x 10 6 5.5 CoC12 1.85xlO 5 110 50 7 8~ x 10-6 5.5 MnC12 1.85xl0 5 110 50 7 8~1 x 10 6 5.5 NiSO4 1.85xlO 5 110 50 7 8.1 x 10 6 5.5 ZnC12 1.85x10-5 llO 50 7 8.1 x 10-6 5.5 These observations demonstrate that chlorine dioxide can remove interfacial pads formed from a variety of soluble metallic salts, including complex mixtures of these materials (not shown in this example). Chlorine dioxide is effective when added to oil/water systems at pH
1 to pH ll in ratios of from as low as 1:100 moles of chlorine dioxide per mole of sulfide to as high as three moles of chlorine dioxide per mole of sulfide. These are not necessarily critical upper and lower limits, but generally define the most effective range of chlorine dioxide to sulfide ratios suitable for use in this invention. The concept of the invention, however, contemplates the use of effective amounts of chlorine dioxide being added to oil/water systems either in the oil phase or the water phase, or both, to contact the sulfide oil/water pad and to thereby elim:inate the pad or prevent the formation of the sulfide pad.
Indu~tria~_~E~L~ion ._ _ This invention finds wide application in petroleum produ~tion an~ refining.
Acetate 5.5 9.74 x 10~7 5.5 Phosphate/Citrate 6.5 1.95 x 1~ 6 6 Phosphate 6 2.9~ x lQ 6 Phosphate 7 3~9 x 10 ~ 6 Tris 6.5 9~74 x 10--7 5.5 Phosphate ~ ~.87 x 10 6 7 Tris 8.5 5.84 x 10 6 7 Borate 8 3.8~ x 10 6 7 Borate 8.S 4~85 x 10 6 8 Tris 9 6.01 x 10 ~ 8.5 ~orate 10 6.Ul x 10-6 8 Carbona~e 10 4.~7 x 10 6 8 Chlorine dioxide can remove oil/water interfacial sulfide pads under a wide variety of temperatures. Several screw cap test tubes were charged with l.OmL ferric chloride (0.037M~ and l~O~IL freshly prepared sodium sulfide (0.037M). The re.sulting mixtures were diluted with 5.0mL of aqueous medium and l.OmL
mineral oil. Upon vigorous shaking, heavy sulfide interfacial pads formed. Then, the tubes were heated to various temperatures. Chlorine dioxide solution was then added at the elevated temperature and r in all cases, the sulfide interfacial pad was removed.
Initial Temperature Moles Final Medium pH _ (~C~
4.2% AST~ 7 21 7.~ x 10 6 6 4.2% ASTM 7 35 5~57 x 10 6 7 4.2% ASTM 7 4b 5.13 x 10 6 7 !
~2~7~.~
--10`-Initial Temperature Moles FinalMedium ~ (C) _ _C~ E~
4.2~ ASTM 7 554.46 x 10 6 7 4.2% ASTM 7 644.23 x 10 6 7 54.2~ ASTM 7 804.12 x 10 6 7 4.2% ASTM 7 964.12 x 10 6 7 0.42~ ASTM 7 211.0 x 10 5 4 O . 42% ASTM 7 4~8 . 91 x 10 5 5 0.42% ASTM 7 558.36 x 10 6 5 lQ0.42~ ASTM 7 708.36 x 10 6 5 n . 42~ ASTM 7 947.8 x 10 ~ 5.5 Phosphate ~uffer 6 ~1 1.78 x 10 5 4 Phosphate Buffer 6 40 1.73 x 10 5 5 Phosphate Buffer 6 55 1.67 x 10 5 6 Phosphate Buffer 6 66 1.67 x 10 5 6 Phosphate Buffer 6 90 1~67 x 10 5 6 Tris Buffer 7 216.13 x 10 6 6,5 Tris Buffer 7 425,5 ~ 10-6 7 Tris Buffer 7 535.5 x 10 6 7 Tris Ruffer 7 645.35 x 10 6 7 Tris Buffer 7 885.35 x 10 6 7 ~orate Buffer 8 211.39 x 10 5 5 Borate huffer ~ 371.23 x 10 5 5.5 Borate Buffer 8 501.11 x 10 5 6 Borate Buffer ~ 701~11 x 10 5 6 Borate ~uffer 8 341.~ x 10 5 6 These results demonstrate the effect of higher temperature on the ability o~ chlorine dioxide to remove interfacial ~ulfide pads. Adding heat to the oil/water system allows less chlorine dioxid~ to be used to accomplish pad removal. This decrease in the amount o~
chlorine dioxide produces an aqueous system with a higher pH.
Agitation of the oil/water system can greatly decrease the time required for a given amount of chlorine dioxide to remove an interfacial sulfjde pad. Two 250mL
flasks were charged with 5,0~L each of ferric chloride ~2~714 ~0.037M) and ~odium sulfide (0.037M) solutions. These mixtures were then diluted with 100ml ASTM brine ~4.2~
and 50ml mineral oil. These sy~tems were shaken tn create a heavy interfacial sulfide p~d. Then, 8.1 x 10-6 moles of chlorine dioxide solution was added to the top portion of one flask without agitation. Six minute~ were required to completely remove the pad under the undis~urbed conditions.
Again, 8.1x10 6 moles chlorine dioxide was added to top portion of the other flask. A magnetic stirring bar was used to create a minor agitation condition at a spinning rate of 20 cps. Under these conditions, the pad disappeared in 30 seconds.
EXA~PLE 7 Chlorine dioxide can be used to remove oil/water interfacial sulfide pads containing metals other than iron Several screw cap test tubes were charged with a soluble metallic salt and an equimolar amount of freshly prepared sodium ~ulfide solution. These mixtures were diluted with 4.2% ASTM bri.ne and mineral oil. Then, chlorine dioxide solution was added which caused removal of the interfacial sulfide pad in all casefi. The data are ~isplayed below.
Metal Moles mL ASTM mL Init.ial Moles Final Salt Sulfide Brine Oil _ pH ~ Z____ __E~L
MnCl~ 3.7x10 5 7 1 7 2.655 x 10 6 6.9 CrC13 3.7x10-5 7 1 7 l.~6 x 10-6 6.9 VC13 3.7x10-5 8 1 7 2.655 x 10-6 6 MnC12 3.7x10 5 12 1 8 2.78 x 10 5 8 MnC12 3.7x10-5 5 10 8 2 23 x 10 5 8 MnC12 3.7x10 5 7 15 ~ 2.23 x 10 5 8 CdC13 3.7x10-5 7 1 7 3.1 x 10-5 CoC12 3.7x10-5 7 1 7 5.31 x 10-4 Pb(OAc)2 3.7x10 5 7 1 7 1.06 x 10 3 AgNO3 3.7x10-5 7 1 7 5.31 x 10 4 SnCl~ 3.7x10-5 7 1 7 1.06 x 10-3 Tl(OAc) 3.7x10 5 7 1 7 1.33 x 10 4 ~2Z7~4 Metal Moles mL ASTM mL Initial Moles Final Salt Sulfide _ ine oil pH
Complex Mixture:
FeCl3 1.85xlO 5 110 50 7 ~.1 x 10 6 5.5 CoC12 1.85xlO 5 110 50 7 8~ x 10-6 5.5 MnC12 1.85xl0 5 110 50 7 8~1 x 10 6 5.5 NiSO4 1.85xlO 5 110 50 7 8.1 x 10 6 5.5 ZnC12 1.85x10-5 llO 50 7 8.1 x 10-6 5.5 These observations demonstrate that chlorine dioxide can remove interfacial pads formed from a variety of soluble metallic salts, including complex mixtures of these materials (not shown in this example). Chlorine dioxide is effective when added to oil/water systems at pH
1 to pH ll in ratios of from as low as 1:100 moles of chlorine dioxide per mole of sulfide to as high as three moles of chlorine dioxide per mole of sulfide. These are not necessarily critical upper and lower limits, but generally define the most effective range of chlorine dioxide to sulfide ratios suitable for use in this invention. The concept of the invention, however, contemplates the use of effective amounts of chlorine dioxide being added to oil/water systems either in the oil phase or the water phase, or both, to contact the sulfide oil/water pad and to thereby elim:inate the pad or prevent the formation of the sulfide pad.
Indu~tria~_~E~L~ion ._ _ This invention finds wide application in petroleum produ~tion an~ refining.
Claims (7)
1. The method of eliminating sulfide pads at oil/water interfaces in the handling and processing of petroleum comprising the steps of introducing an effective amount of chlorine dioxide to the oil/water interface and causing the chlorine dioxide to react at said interface at a pH of from 1 to 11 with sulfides at said interface to disperse said sulfides from the oil/water interface.
2. The method of Claim 1 wherein the reaction is carried out from pH 4 to pH 9.
3. The method of Claim 1 or Claim 2 wherein chlorine dioxide is introduced in an amount to result in a ratio of from 1:100 to 3:1 chlorine dioxide to sulfide at said interface.
4. The method of Claim 1 wherein the chlorine dioxide is introduced in an effective amount of at least one part of chlorine dioxide for every one hundred parts of sulfide at the oil/water interface.
5. The method of Claim 1 wherein the chlorine dioxide is introduced in an effective amount of at least one part of chlorine dioxide for every thirty parts of sulfide at the oil/water interface.
6. The method of Claim 4 or Claim 5 in which causing the chlorine dioxide to react at said interface comprises agitating the oil/water interface.
7. The method of Claim 4 or Claim 5 in which causing the chlorine dioxide to react at said interface comprises heating the oil/water interface from about 0° C
to about 200°C.
to about 200°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US54110483A | 1983-10-12 | 1983-10-12 | |
| US541,104 | 1983-10-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1222714A true CA1222714A (en) | 1987-06-09 |
Family
ID=24158188
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000461045A Expired CA1222714A (en) | 1983-10-12 | 1984-08-15 | Method for removing insoluble sulfide pads at oil/water interfaces |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0157793A4 (en) |
| JP (1) | JPS60501496A (en) |
| CA (1) | CA1222714A (en) |
| WO (1) | WO1985001722A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| MX364960B (en) | 2011-03-22 | 2019-05-15 | Sabre Ip Holdings Llc | Chlorine dioxide precursor and methods of using same. |
| US9238587B2 (en) | 2013-03-15 | 2016-01-19 | Sabre Intellectual Property Holdings Llc | Method and system for the treatment of water and fluids with chlorine dioxide |
| US10442711B2 (en) | 2013-03-15 | 2019-10-15 | Sabre Intellectual Property Holdings Llc | Method and system for the treatment of produced water and fluids with chlorine dioxide for reuse |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US310049A (en) * | 1884-12-30 | granger | ||
| US4077879A (en) * | 1976-06-04 | 1978-03-07 | Olin Corporation | Treatment of sulfide-bearing waters with chlorine dioxide |
-
1984
- 1984-08-15 CA CA000461045A patent/CA1222714A/en not_active Expired
- 1984-08-20 WO PCT/US1984/001335 patent/WO1985001722A1/en not_active Application Discontinuation
- 1984-08-20 JP JP59503285A patent/JPS60501496A/en active Granted
- 1984-08-20 EP EP19840903311 patent/EP0157793A4/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| EP0157793A1 (en) | 1985-10-16 |
| JPS60501496A (en) | 1985-09-12 |
| EP0157793A4 (en) | 1986-08-21 |
| WO1985001722A1 (en) | 1985-04-25 |
| JPS6333404B2 (en) | 1988-07-05 |
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