WO2007144696A2 - Method to deactivate corrosive sulfur in insulation - Google Patents

Method to deactivate corrosive sulfur in insulation Download PDF

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Publication number
WO2007144696A2
WO2007144696A2 PCT/IB2006/004295 IB2006004295W WO2007144696A2 WO 2007144696 A2 WO2007144696 A2 WO 2007144696A2 IB 2006004295 W IB2006004295 W IB 2006004295W WO 2007144696 A2 WO2007144696 A2 WO 2007144696A2
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WO
WIPO (PCT)
Prior art keywords
oil
insulating oil
sulfide
forming compound
copper
Prior art date
Application number
PCT/IB2006/004295
Other languages
French (fr)
Other versions
WO2007144696A3 (en
Inventor
Arne Hjortsberg
Karin Gustafsson
Mats Dahlund
Original Assignee
Abb Research Ltd.
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
Application filed by Abb Research Ltd. filed Critical Abb Research Ltd.
Publication of WO2007144696A2 publication Critical patent/WO2007144696A2/en
Publication of WO2007144696A3 publication Critical patent/WO2007144696A3/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/08—Cooling; Ventilating
    • H01F27/10—Liquid cooling
    • H01F27/12—Oil cooling
    • H01F27/14—Expansion chambers; Oil conservators; Gas cushions; Arrangements for purifying, drying, or filling
    • 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
    • C10G75/00—Inhibiting corrosion or fouling in apparatus for treatment or conversion of hydrocarbon oils, in general
    • C10G75/02—Inhibiting corrosion or fouling in apparatus for treatment or conversion of hydrocarbon oils, in general by addition of corrosion inhibitors

Definitions

  • the present invention relates to removing corrosive sulfur from insulation oil, such as insulation oil in transformers.
  • Power transformers, distribution transformers and reactors usually include an insulation system consisting of oil and cellulose These two components have been used for a long time due to their relatively low price and good performance.
  • the dielectric strength of such an insulation system is strongly dependent on its insulating properties.
  • copper sulfide such as copper(I)sulfide
  • copper(I)sulfide deposits forming on conductors and in solid insulation in transformers.
  • Copper sulfide deposits can lower the initiation level for partial discharges (PD).
  • PD activity may lead to degradation of the solid insulation and ultimately to dielectric breakdown.
  • copper sulfide growth may be so extensive that conductive bridges are formed through several layers of conductor covering paper. In such cases failures may occur even in the absence of extra-ordinary stresses.
  • conductor insulation typically includes paper wrapping, for example, and sometimes also spacers separating the conductors from each other.
  • the conductors may be insulated with paper wrapping. Both the conductor insulation and the spacers will then be very sensitive for copper(I)sulfide deposits.
  • Reactions leading to copper sulfide formation can be prevented or suppressed by removing or reducing active copper and sulfur containing components.
  • conventional insulating oil processing techniques such as reconditioning and reclaiming have little or no effect.
  • Reclaiming which is typically carried out by treating the oil with a sorbent for polar contaminants, such as Fullers earth or alumina, has as its primary purpose to remove oxidation products from aged oil, and restore it to a condition similar to that of new oil. Copper mercaptides and other copper-organic compounds can be removed with this process.
  • the effect on active sulfur species can vary depending on the process used, and the effect on compounds like mercaptans, sulfides and disulfides can be small.
  • the present invention provides simple methods for addressing problems resulting from use of corrosive insulation oil.
  • the present invention provides a method of deactivating corrosive sulfur in insulating oil. The method includes adding at least one sulfide forming compound to the insulating oil in oil soluble form in an amount sufficient to react with corrosive sulfur compounds in the oil.
  • the present invention provides methods for deactivating corrosive sulfur in insulation oil.
  • One or more compounds that react with sulfur compounds may be added to the insulation oil.
  • the added compound(s) can react with the corrosive sulfur compounds.
  • the corrosive sulfur compounds are prevented from forming copper sulfide deposits in the insulation and/or on conductors. It is thought that the present invention operates by the added compounds, such as copper containing compounds, react with corrosive compounds, such as corrosive sulfur species, in the oil, thus rendering the corrosive compounds harmless.
  • the added compound(s) typically are oil soluble. Also, the added compound(s) typically are sulfide forming compounds.
  • the sulfide forming compound(s) may include one or more metals.
  • the added compound(s) include sulfide forming copper compounds.
  • One particular example of such an embodiment includes adding copper naphthenate to the insulating oil.
  • Other oil-soluble salts and preparations of copper or of other metals such as iron and zinc can also be used.
  • the amount of compound(s) added to the oil may depend upon the level of corrosive sulfur compounds that the oil contains and the relative number of added compound molecules that react with corrosive sulfur compound molecules.
  • the amount of compound(s) added to the oil may also depend upon the speed with which it is desired to deactivate the corrosive sulfur compounds. More added compounds may be added to the oil if is it desired to deactivate the corrosive sulfur compounds quickly.
  • the amount of added compounds may be sufficient to suppress and/or prevent the corrosive sulfur compounds from forming copper sulfide deposits on conductors, insulation, and/or other surfaces.
  • the added compound(s) may include copper naphthenate at a concentration range of from about 10 to about 500 mg Cu/kg of insulating oil.
  • a guideline for estimating a suitable dose is that a small surplus may be added, based on the stochiometric proportions of the sulfide and the amount of reactive sulfur in the oil.
  • the dose may be determined by lab-scale treatment on small samples.
  • the added compounds may be introduced into the insulating oil with any procedure currently in use for adding materials to insulation oil. For example, procedures currently utilized for adding antioxidant or metal passivator may be utilized. No special procedures or means may be necessary to introduce the added compounds into the oil.
  • reaction products resulting from reactions between the added the added compound(s) and the corrosive compounds as well as excess unreacted added compound(s) may be removed.
  • the insulating oil may have acceptable properties even without carrying out any reclaiming process.
  • reaction products and excess added compound(s) may be removed from the oil.
  • the amount of time that the added compounds may remain in the oil can vary. Typically,' the compounds may remain in the oil until the presence of corrosive compounds, particularly corrosive sulfur compounds, is reduced or eliminated.
  • reaction products resulting from reactions between the added compounds and corrosive sulfur compounds and excess added compounds, such as copper can be removed from the insulating oil.
  • the reaction products and excess added compounds may be removed by utilizing standard procedures. For example, standard oil reclaiming processes may be utilized. According to one particular example, on-line processing may be utilized.
  • the present invention can fulfill the potentially large demand for methods to reduce corrosive components in insulating oil.
  • the simplicity of the present invention makes the present invention particularly attractive to reduce corrosive components in insulating oil.
  • the lack of special equipment necessary to carry out the present invention makes this particularly true.

Landscapes

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

Abstract

A method for deactivating corrosive sulfur in insulating oil. At least one sulfide forming compound is added to the insulating oil in oil soluble form in an amount sufficient to react with corrosive sulfur compounds in the oil.

Description

43315-239036
METHOD TO DEACTIVATE CORROSIVE SULFUR IN INSULATION OIL
Cross-reference To Related Application
This application claims priority to U.S. provisional patent application 60/754,625 filed
30 December 2005.
Field of the Invention
The present invention relates to removing corrosive sulfur from insulation oil, such as insulation oil in transformers.
Background of the Invention
Power transformers, distribution transformers and reactors usually include an insulation system consisting of oil and cellulose These two components have been used for a long time due to their relatively low price and good performance. The dielectric strength of such an insulation system is strongly dependent on its insulating properties.
One problem that occurs with insulating oils used in power transformers, distribution transformers and reactors is copper sulfide, such as copper(I)sulfide, deposits forming on conductors and in solid insulation in transformers. Copper sulfide deposits can lower the initiation level for partial discharges (PD). With deposition in areas of the windings, with high electrical stresses and under certain operating conditions, especially the abundance of transients, PD activity may lead to degradation of the solid insulation and ultimately to dielectric breakdown. In extreme cases copper sulfide growth may be so extensive that conductive bridges are formed through several layers of conductor covering paper. In such cases failures may occur even in the absence of extra-ordinary stresses.
An example of an area where the electrical stress is high is between turns in the windings. This turn-to-tum insulation is typically built up by conductor insulation, which may include paper wrapping, for example, and sometimes also spacers separating the conductors from each other. The conductors may be insulated with paper wrapping. Both the conductor insulation and the spacers will then be very sensitive for copper(I)sulfide deposits.
Problems of copper sulfide formation in transformer insulation have increased in the last ten to fifteen years. This appears to be due at least in part to increased corrosivity of insulating oils. Many transformers are filled with corrosive oil. While new less corrosive oils are being developed, it may take several years for new specifications take effect world wide. Also, it may take years to secure sufficient supplies of harmless oils. As a result, many more transformers and reactors will be filled with corrosive insulting oils. Furthermore, it will take time for cycles of transformer and transformer oil replacement to result in the elimination of corrosive insulating oils.
Reactions leading to copper sulfide formation can be prevented or suppressed by removing or reducing active copper and sulfur containing components. However, conventional insulating oil processing techniques, such as reconditioning and reclaiming have little or no effect. Reclaiming, which is typically carried out by treating the oil with a sorbent for polar contaminants, such as Fullers earth or alumina, has as its primary purpose to remove oxidation products from aged oil, and restore it to a condition similar to that of new oil. Copper mercaptides and other copper-organic compounds can be removed with this process. However, the effect on active sulfur species can vary depending on the process used, and the effect on compounds like mercaptans, sulfides and disulfides can be small.
Summary of the Invention
The present invention provides simple methods for addressing problems resulting from use of corrosive insulation oil. According to one aspect, the present invention provides a method of deactivating corrosive sulfur in insulating oil. The method includes adding at least one sulfide forming compound to the insulating oil in oil soluble form in an amount sufficient to react with corrosive sulfur compounds in the oil.
Further objectives and advantages, as well as the structure and function of exemplary embodiments will become apparent from a consideration of the description and examples.
Detailed Description of Embodiments of the Invention
Embodiments of the invention are discussed in detail below. In describing embodiments, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected. While specific exemplary embodiments are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations can be used without parting from the spirit and scope of the invention.
The present invention provides methods for deactivating corrosive sulfur in insulation oil. One or more compounds that react with sulfur compounds may be added to the insulation oil. The added compound(s) can react with the corrosive sulfur compounds. Through the reaction with the added compound(s), the corrosive sulfur compounds are prevented from forming copper sulfide deposits in the insulation and/or on conductors. It is thought that the present invention operates by the added compounds, such as copper containing compounds, react with corrosive compounds, such as corrosive sulfur species, in the oil, thus rendering the corrosive compounds harmless.
The added compound(s) typically are oil soluble. Also, the added compound(s) typically are sulfide forming compounds. The sulfide forming compound(s) may include one or more metals. According to one particular embodiment, the added compound(s) include sulfide forming copper compounds. One particular example of such an embodiment includes adding copper naphthenate to the insulating oil. Other oil-soluble salts and preparations of copper or of other metals such as iron and zinc can also be used.
The amount of compound(s) added to the oil may depend upon the level of corrosive sulfur compounds that the oil contains and the relative number of added compound molecules that react with corrosive sulfur compound molecules. The amount of compound(s) added to the oil may also depend upon the speed with which it is desired to deactivate the corrosive sulfur compounds. More added compounds may be added to the oil if is it desired to deactivate the corrosive sulfur compounds quickly. The amount of added compounds may be sufficient to suppress and/or prevent the corrosive sulfur compounds from forming copper sulfide deposits on conductors, insulation, and/or other surfaces.
According to one particular embodiment, the added compound(s) may include copper naphthenate at a concentration range of from about 10 to about 500 mg Cu/kg of insulating oil. Whichever sulfide forming agent is used, a guideline for estimating a suitable dose is that a small surplus may be added, based on the stochiometric proportions of the sulfide and the amount of reactive sulfur in the oil. For a specific combination of agent and oil type, the dose may be determined by lab-scale treatment on small samples.
The added compounds may be introduced into the insulating oil with any procedure currently in use for adding materials to insulation oil. For example, procedures currently utilized for adding antioxidant or metal passivator may be utilized. No special procedures or means may be necessary to introduce the added compounds into the oil.
After the introduction of the added compounds into the insulating oil and the reaction of the added compound(s) with corrosive compounds in the oil, reaction products resulting from reactions between the added the added compound(s) and the corrosive compounds as well as excess unreacted added compound(s) may be removed. However, it is not necessary to carry out any removal process. In many cases, the insulating oil may have acceptable properties even without carrying out any reclaiming process.
In other cases, the reaction products and excess added compound(s) may be removed from the oil. The amount of time that the added compounds may remain in the oil can vary. Typically,' the compounds may remain in the oil until the presence of corrosive compounds, particularly corrosive sulfur compounds, is reduced or eliminated. According to one embodiment, when the corrosivity and ability of the oil to form copper sulfide has disappeared, reaction products resulting from reactions between the added compounds and corrosive sulfur compounds and excess added compounds, such as copper, can be removed from the insulating oil. The reaction products and excess added compounds may be removed by utilizing standard procedures. For example, standard oil reclaiming processes may be utilized. According to one particular example, on-line processing may be utilized.
. The present invention can fulfill the potentially large demand for methods to reduce corrosive components in insulating oil. The simplicity of the present invention makes the present invention particularly attractive to reduce corrosive components in insulating oil. The lack of special equipment necessary to carry out the present invention makes this particularly true.
The embodiments illustrated and discussed in this specification are intended only to teach those skilled in the art the best way known to the inventors to make and use the invention. Nothing in this specification should be considered as limiting the scope of the present invention. All examples presented are representative and non-limiting. The above-described embodiments of the invention may be modified or varied, without departing from the invention, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the claims and their equivalents, the invention may be practiced otherwise than as specifically described.

Claims

ClaimsWe claim:
1. A method for deactivating corrosive sulfur in insulating oil, the method comprising; adding at least one sulfide forming compound to the insulating oil in oil soluble form in an amount sufficient to react with corrosive sulfur compounds in the insulating oil.
2. The method according to claim 1, wherein the insulating oil is added transformer ' insulating oil in a transformer and the sulfide forming compound prevents the corrosive sulfur compounds from forming copper sulfide deposits on conductors and in solid insulation in the transformer.
3. The method according to claim 1, further comprising: removing from the insulating oil reaction products resulting from reaction of the at least one sulfide forming compound with the corrosive sulfur compounds.
4. The method according to claim 3, wherein removing the reaction products comprises: carrying out an oil reclamation process.
5. The method according to claim 4, wherein the oil reclamation process is carried out on-line.
6. The method according to claim 1, further comprising: removing from the insulating oil unreacted sulfide forming compound.
7. The method according to claim 1, wherein the at least one sulfide forming compound comprises a metal.
8. The method according claim 7, wherein the at least one sulfide forming compound comprises a compound including at least one of copper, iron or zinc.
9. The method according to claim 8, wherein the at least one sulfide forming compound comprises copper naphthenate.
10. The method according to claim 8, wherein the at least one sulfide forming compound comprises an oil-soluble salt of at least one of copper, iron or zinc.
11. The method according to claim 8, wherein the at least one sulfide forming compound comprises a copper compound added to the insulating oil in a concentration range of from about 10 to about 500 mg Cu/kg.
12. The method according to claim 1 , further comprising: measuring an amount of corrosive sulfur compounds in the insulating oil; and adding an amount of the at least one sulfide forming compound to the insulating oil that exceeds a stochiometric proportion needed to react with measured amount of corrosive sulfur compounds.
13. The method according to claim 1, further comprising: monitoring the insulating oil for corrosivity and ability of the insulating oil to form copper sulfide; and removing the at least one sulfide forming compound from the insulating oil upon ceasing to detect corrosivity and ability of the insulating oil to form copper sulfide.
PCT/IB2006/004295 2005-12-30 2006-12-28 Method to deactivate corrosive sulfur in insulation WO2007144696A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US75462505P 2005-12-30 2005-12-30
US60/754,625 2005-12-30

Publications (2)

Publication Number Publication Date
WO2007144696A2 true WO2007144696A2 (en) 2007-12-21
WO2007144696A3 WO2007144696A3 (en) 2008-02-21

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NO20151036A1 (en) * 2015-08-18 2017-02-20 Vpdiagnose As Method for removal of elemental sulfur from transformer/electrical insulation oils.
NO342821B1 (en) * 2017-12-28 2018-08-13 Vpdiagnose As Method for removal of elemental sulfur from transformer/electrical insulation oils

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE538866A (en) *
DE961648C (en) * 1952-10-23 1957-04-11 Exxon Research Engineering Co Process to reduce the corrosivity of mineral oil distillates towards metals
FR2352876A1 (en) * 1976-05-29 1977-12-23 Reinhausen Kg Maschf Removal of corrosive sulphur from insulating oil - by contact with chemical or physical absorbents
US4163708A (en) * 1975-06-27 1979-08-07 Chevron Research Company Process for the removal of thiols from hydrocarbon oils
JP2001311083A (en) * 2000-04-27 2001-11-09 Mitsubishi Electric Corp Apparatus and method for removing sulfur compound in insulating oil
JP2005223104A (en) * 2004-02-05 2005-08-18 Tm T & D Kk Method of diagnosing and suppressing electrostatic charge of oil-filled electrical apparatus
WO2005115082A2 (en) * 2004-04-30 2005-12-08 Abb Technology Ltd. Method for removal of reactive sulfur from insulating oil by exposing the oil to a sulfur scanvenger and a polar sorbent

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62267648A (en) * 1986-05-16 1987-11-20 Toshiba Corp Method of discriminating silver corrosiveness of insulating oil

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE538866A (en) *
DE961648C (en) * 1952-10-23 1957-04-11 Exxon Research Engineering Co Process to reduce the corrosivity of mineral oil distillates towards metals
US4163708A (en) * 1975-06-27 1979-08-07 Chevron Research Company Process for the removal of thiols from hydrocarbon oils
FR2352876A1 (en) * 1976-05-29 1977-12-23 Reinhausen Kg Maschf Removal of corrosive sulphur from insulating oil - by contact with chemical or physical absorbents
JP2001311083A (en) * 2000-04-27 2001-11-09 Mitsubishi Electric Corp Apparatus and method for removing sulfur compound in insulating oil
JP2005223104A (en) * 2004-02-05 2005-08-18 Tm T & D Kk Method of diagnosing and suppressing electrostatic charge of oil-filled electrical apparatus
WO2005115082A2 (en) * 2004-04-30 2005-12-08 Abb Technology Ltd. Method for removal of reactive sulfur from insulating oil by exposing the oil to a sulfur scanvenger and a polar sorbent

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NO20151036A1 (en) * 2015-08-18 2017-02-20 Vpdiagnose As Method for removal of elemental sulfur from transformer/electrical insulation oils.
NO342024B1 (en) * 2015-08-18 2018-03-12 Vpdiagnose As Method for removal of elemental sulfur from transformer/electrical insulation oils.
NO342821B1 (en) * 2017-12-28 2018-08-13 Vpdiagnose As Method for removal of elemental sulfur from transformer/electrical insulation oils

Also Published As

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