NO342024B1 - Method for removal of elemental sulfur from transformer/electrical insulation oils. - Google Patents
Method for removal of elemental sulfur from transformer/electrical insulation oils. Download PDFInfo
- Publication number
- NO342024B1 NO342024B1 NO20151036A NO20151036A NO342024B1 NO 342024 B1 NO342024 B1 NO 342024B1 NO 20151036 A NO20151036 A NO 20151036A NO 20151036 A NO20151036 A NO 20151036A NO 342024 B1 NO342024 B1 NO 342024B1
- Authority
- NO
- Norway
- Prior art keywords
- oil
- tpp
- electrical insulation
- phosphine
- elemental sulfur
- Prior art date
Links
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 title claims abstract description 44
- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000010292 electrical insulation Methods 0.000 title claims description 11
- 239000003921 oil Substances 0.000 title description 36
- RIOQSEWOXXDEQQ-UHFFFAOYSA-N triphenylphosphine Chemical compound C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1 RIOQSEWOXXDEQQ-UHFFFAOYSA-N 0.000 claims description 71
- XYFCBTPGUUZFHI-UHFFFAOYSA-N Phosphine Chemical compound P XYFCBTPGUUZFHI-UHFFFAOYSA-N 0.000 claims description 30
- 229910000073 phosphorus hydride Inorganic materials 0.000 claims description 15
- 229910052717 sulfur Inorganic materials 0.000 claims description 13
- 239000011593 sulfur Substances 0.000 claims description 12
- FIQMHBFVRAXMOP-UHFFFAOYSA-N triphenylphosphane oxide Chemical compound C=1C=CC=CC=1P(C=1C=CC=CC=1)(=O)C1=CC=CC=C1 FIQMHBFVRAXMOP-UHFFFAOYSA-N 0.000 claims description 7
- 229930195733 hydrocarbon Natural products 0.000 claims description 6
- 150000002430 hydrocarbons Chemical class 0.000 claims description 6
- 239000000843 powder Substances 0.000 claims description 5
- 239000004215 Carbon black (E152) Substances 0.000 claims description 4
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 3
- 239000007789 gas Substances 0.000 claims description 2
- PBHVCRIXMXQXPD-UHFFFAOYSA-N chembl2369102 Chemical compound C1=CC(S(=O)(=O)O)=CC=C1C(C1=CC=C(N1)C(C=1C=CC(=CC=1)S(O)(=O)=O)=C1C=CC(=N1)C(C=1C=CC(=CC=1)S(O)(=O)=O)=C1C=CC(N1)=C1C=2C=CC(=CC=2)S(O)(=O)=O)=C2N=C1C=C2 PBHVCRIXMXQXPD-UHFFFAOYSA-N 0.000 claims 2
- 238000005070 sampling Methods 0.000 claims 2
- 239000002184 metal Substances 0.000 abstract description 6
- 229910052751 metal Inorganic materials 0.000 abstract description 6
- 239000000126 substance Substances 0.000 abstract description 6
- 230000008901 benefit Effects 0.000 abstract description 2
- 238000011065 in-situ storage Methods 0.000 abstract description 2
- 150000002739 metals Chemical class 0.000 abstract description 2
- 230000007613 environmental effect Effects 0.000 abstract 1
- 239000005864 Sulphur Substances 0.000 description 16
- 238000006243 chemical reaction Methods 0.000 description 10
- 230000008569 process Effects 0.000 description 7
- 239000000047 product Substances 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 238000011282 treatment Methods 0.000 description 6
- 239000000654 additive Substances 0.000 description 4
- 125000004429 atom Chemical group 0.000 description 4
- 229920002678 cellulose Polymers 0.000 description 4
- 239000001913 cellulose Substances 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 238000004128 high performance liquid chromatography Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 239000002199 base oil Substances 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 150000001787 chalcogens Chemical group 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005755 formation reaction Methods 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 150000003003 phosphines Chemical class 0.000 description 2
- 230000007420 reactivation Effects 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- -1 corrosive sulphur Chemical compound 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000010735 electrical insulating oil Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 229910000286 fullers earth Inorganic materials 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 125000001183 hydrocarbyl group Chemical group 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000009972 noncorrosive effect Effects 0.000 description 1
- 150000002903 organophosphorus compounds Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 125000004434 sulfur atom Chemical group 0.000 description 1
- 150000003464 sulfur compounds Chemical class 0.000 description 1
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
- H01F27/23—Corrosion protection
-
- 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
- H01F27/125—Cooling by synthetic insulating and incombustible liquid
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transformer Cooling (AREA)
Abstract
The patent claimed to protect the in-situ method of addition of a specific group of chemical substances to protect metals in transformere and other insulating oil filled apparatuses from sulphidation caused by elemental sulphur. The purpose is to provide a cost efficient alternative method for the apparatuses owners in combination with providing a significant environmental advantage.The patent claimed to protect the in-situ method of addition of a specific group of chemical substances to protect metals in transformers and other insulating oil filled apparatuses from sulphidation caused by elemental sulfur. The purpose is to provide a cost efficient alternative method for the apparatuses owners in combination with providing a significant environmental advantage.
Description
Field of the invention
Method for removal of elemental sulfur from transformer/electrical insulation oils operating in strong electrical and magnetic fields.
Background.
During the latest decades, sulphidation has appeared as a problem in electrical oil insulated apparatuses such as transformers, reactors, breakers, and auxiliary devices like e.g. tap changers. In short; anything containing electrical insulation oils and which operates in strong electrical and/or magnetic fields.
The main uses for these oils in transformers are electrical insulation and cooling i.e. to remove heat dissipated from hot surfaces inside the device. For breakers an additional oil function is that of disrupting/quenching the arc that develop during the breaking action.
The sulphidation has been reported to cause disrupted operation and in some cases even costly failures. The failure cause has been and to some extent continue to be “unknown” even by professionals.
From the chemical point of view any molecule/compound that contain one or more sulphur atoms has the potential to become a sulphur source for sulphidation processes.
However, it has become known that certain additives have been used by some insulation oils manufacturing industries, merely for the purpose of boosting their oil product performance in testing methods as defined by International Standard ́s requirements. It has lead to a change in the International Standards so that now, no additives are allowable, unless they are declared and accepted by the purchaser/user.
However, under certain conditions these additives remain a potential problem in transformers in operation and sometimes the owner decides to “regenerate oil” i.e. remove polar molecules e.g. molecules formed due to oxidation or other degradation processes which appear as a consequence of the chemical reaction conditions inside a transformer.
Some of these processes reuse the polar compound adsorption material (usually Fullers Earth) by a reactivation process where adsorbed hydrocarbons are removed by different processes. In instances when this reactivation process is not completed, the adsorption material may produce/release sulfur in a corrosive form.
It has also been found (by the patent applicant) that elemental sulfur is found in transformers in normal operation and thus is a consequence of not defined processes inside the transformers.
There is an obvious need to inhibit the function of elemental sulfur in order to prevent metal sulphidation (predominantly silver and copper sulphidation).
DE2624239A describes an equipment for treating insulating oil in oil-filled high-voltage electrical plant. The equipment has an active contact substance capable of removing corrosive sulphur when in direct contact with the oil. The active contact substance may then remove the sulphur by a chemical reaction or by absorption.
WO2007144696A is a method for deactivating corrosive sulfur in insulating oil by adding at least one sulfide forming, generally a metal based compound to the insulating oil in oil soluble form in an amount sufficient to react with corrosive sulfur compounds in the oil, for remove from the insulating oill these compunds which may be formed due to oil regenerations processes.
Short summary of the invention
The invention concerns the use of active phosphines with high selectivity to react with atoms in the chalcogen group such as Oxygen and Sulfur and is an in-situ method for removal of elemental sulfur from electrical insulating oil in an oil filled apparatus comprising, to determine the level of elemental sulfur in the electrical insulation oil and then slowly add highly concentrated phosphine product to the oil. The phosphine product react with the elemental sulphur and form a stable product thus preventing the elemental sulfur from causing metal sulphidation and preventing possible damage and breakdown of electrical oil insulated apparatuses.
The phosphine product is added in an amount 4 -5 times higher than the elemental sulphur content in the oil. This is advantageous, as this forms a buffer for reacting with more elemental sulfur “leaking out” from winding cellulose and other porous parts of the transformer interior.
In an embodiment of the invention the phosphine product added is Triphenylphosphine (TPP), favorable due to the large and “dense” appearance of the phenyl group which may create a major increase in selectivity towards atoms such as sulfur and oxygen.
Embodiments of the invention
The invention concerns the use of active phosphines with high selectivity to react with atoms in the chalcogen group such as Oxygen and Sulfur.
Insulating oils contain a large variety of sulphur containing hydrocarbons. The better refined the oil is, the less sulphur it will contain. There is a general risk that metals that come in contact with oil may be caused to sulphidize i.e. corrode under certain conditions. Sulphur induced corrosion is revealed by a dark (brown or more commonly black) deposition on the metal and on/in the surrounding cellulose.
This will reduce the insulating ability of the cellulose and the risk for electron migration will increase.
Elemental sulphur exists mainly in three forms including as cyclic molecules having six, seven and most commonly (i.e. most stable) eight sulphur atoms (S6, S7and S8).
Triphenylphosphine (C18H15P) (with CAS number 603-35-0), hereinafter referred to as TPP, is an organophosphorus compound with molecular weight 262.29 g/mol. The compound appearance is as white powder, which is solid at standard temperature and pressure.
TPP react immediately i.e. very quickly form TPPS with sulphur atoms from S6, S7or S8molecules i.e. with elemental sulphur.
The only reaction product is triphenylephosphinsulphide (abbreviated TPPS). One molecule TPP bind one sulfur atom and consequently eight molecules of TPP is consumed by one S8molecule.
Insulating oil, that at corrosion tests have shown that they contain elemental sulphur i.e. corrosive sulphur, have been treated with TPP. The corrosion test following the TPP-addition indicate no further presence of elemental sulphur. The effect has been statistically confirmed through multiples samples and with real transformers.
Through the addition of TPP to the oil, the problems related sulphur corrosion is completely eliminated. Elemental sulphur formation has proven to be a very common consequence of oil regeneration. Moreover, it is concluded that TPPS is a very stable and thus a non-corrosion-creating sulphide even at extremely high transformer oil temperatures.
The phosphine molecule may be of different chemical composition but due to its wide spread use in different chemistry related industrial manufacturing processes, TPP (Tri-Phenyl-Phosphine) is suitable to use. The phenyl groups may be substituted with any hydrocarbon group to form a phosphine molecule but there is a distinct advantage for TPP due to the large and “dense” appearance of the phenyl group which may create a major increase in selectivity towards atoms such as sulfur and oxygen.
Chromatogram showing the TPP, TPPO and TPPS retention times. These are of course dependent on the analytical conditions set for the GC.
In the chromatogram, the ease of determining the presence of TPP, TPPO (Triphenylphosphine oxide) and TPPS by use of a dedicated detector is illustrated. The chromatogram has been obtained in laboratory testing to determine the selectivity of the reaction when using a sulfur free standard base oil for insulation oil manufacturing purposes. No other reactions involving TPP are seen (the GC run was 21 minutes).
In order to determine the TPP ability to react with sulphur even at room temperature (22° Celsius), TPP and S was mixed and analyzed using High Pressure Liquid Chromatography (HPLC). In HPLC the sample is not subjected to elevated temperature when injected and thus the results will ascertain the no reaction has taken place in the injector (In gas chromatography the injector is normally heated to temperatures above 150° Celsius resulting in possible misinterpretations).
The conclusion of that investigation was that sulfur and oxygen compete to react with TPP. This opens up for different methods to apply treatment:
1. The oil is degassed prior to the introduction of TPP. TPP is then added either in powder form or in the form of a concentrated hydrocarbon based solution of TPP. The purpose of degassing is to decrease the oxygen reaction with TPP in favor of the sulfur reaction. It is a costlier method of addition but is also a more sulfur directed method. It will also create a larger “buffer” inside the unit where TPP remain and may be consumed later on as more elemental sulfur is “leaking out” from winding cellulose and other porous parts.
2. It is added, either as powder or in a concentrated hydrocarbon based solution but with no prior degassing. The method will require less preparation and should be performed on a unit where the oil is warm to enable quick reaction.
3. In a cold unit with circulation going, the addition of concentrated hydrocarbon based TPP solution is preferred because TPP solubility time is dependent on absolute temperature and powder may result in particles entering the electrical field.
Any combination of these methods is possible.
Reactions
How this invention is applied and what is gained.
The invention creates a possibility to counter-act corrosive behaviour experienced when testing properties of certain insulating or base oils. The sulphidation reactions are inhibited with an almost 100 % efficiency due to that the reactive sulfur is transformed into a non reactive variety namely TPPS (if the phosphine selected is TPP).
Laboratory testing has shown that oils that under standardized test conditions produced a “non-corrosive” result after TPP addition, on both silver and copper.
342024
6
Treated oils have been tested also for Breakdown Voltage and Tan delta (loss factor at 90° Celsius) and no negative effects have been found. This is also the expected result due to the very low level of additive used.
The treatment procedure is as follows:
1. Determine the level of elemental sulfur in the transformer. Select a treatment level of 4-5 times this concentration in order to establish a chemical buffer that remain after the treatment has been finished.
2. Remove gases present in the transformer oil in order to decrease the competing TPPO formation reaction.
3. Use a dosing pump to slowly add the liquid containing highly concentrated TPP or other selected phosphine product. The ideal addition time is 24 hours but for practical reasons shorter times will be applied. It is essential to understand the importance of diluting the TPP.
4. Sample from incoming flow to degasser to determine obtained TPP and TPPS concentration.
5. Sample one week, one month and 6 months later to determine TPP, TPPS and TPPO.
The gain for transformer and other machine owners is that no expensive treatments are required and that oil change can be avoided. Consequently this is an environmentally friendly treatment method.
Claims (8)
1. An method for removal of elemental sulfur from electrical insulation oil in an oil filled apparatus comprising
-determine the level of elemental sulfur in the electrical insulation oil,
-slowly add highly concentrated phosphine product, corresponding to 4-5 times the level of the determined sulfur level, to the oil.
2. The method according to any claim 1, wherein Tri-Phenyl-Phosphine (TPP) is used as the phosphine product.
3. The method according to any of the preceding claims, further comprising, before adding the phosphine product, remove gases present in the electrical insulation oil.
4. The method according to any of the preceding claims, adding the highly concentrated phosphine product as a powder.
5. The method according to any of the preceding claims, adding the highly concentrated phosphine product as of concentrated hydrocarbon based solution.
6. The method according to any of the preceding claims, add the highly concentrated phosphine product to the oil for a period of 24 hours.
7. The method according to any of the preceding claims, sampling from the electrical insulation oil from the incoming flow to a degasser to determine obtained TPP and TPPS concentration.
8. The method according to any of the preceding claims, sampling from the electrical insulation oil after one week, one month and/or after 6 months after phosphine product addition to the electrical insulation oil to determine TPP, TPPS (Triphenylephosphine sulphide) and TPPO (Triphenylphosphine oxide).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO20151036A NO342024B1 (en) | 2015-08-18 | 2015-08-18 | Method for removal of elemental sulfur from transformer/electrical insulation oils. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO20151036A NO342024B1 (en) | 2015-08-18 | 2015-08-18 | Method for removal of elemental sulfur from transformer/electrical insulation oils. |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| NO20151036A1 NO20151036A1 (en) | 2017-02-20 |
| NO342024B1 true NO342024B1 (en) | 2018-03-12 |
Family
ID=58645968
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NO20151036A NO342024B1 (en) | 2015-08-18 | 2015-08-18 | Method for removal of elemental sulfur from transformer/electrical insulation oils. |
Country Status (1)
| Country | Link |
|---|---|
| NO (1) | NO342024B1 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2624239A1 (en) * | 1976-05-29 | 1977-12-15 | Reinhausen Maschf Scheubeck | DEVICE FOR PROCESSING THE INSULATING OIL FROM HIGH VOLTAGE DEVICES |
| US20010033938A1 (en) * | 2000-02-11 | 2001-10-25 | Kalina Alexander I. | Method of preventing or stopping sulfuric corrosion of metals |
| WO2007144696A2 (en) * | 2005-12-30 | 2007-12-21 | Abb Research Ltd. | Method to deactivate corrosive sulfur in insulation |
-
2015
- 2015-08-18 NO NO20151036A patent/NO342024B1/en unknown
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2624239A1 (en) * | 1976-05-29 | 1977-12-15 | Reinhausen Maschf Scheubeck | DEVICE FOR PROCESSING THE INSULATING OIL FROM HIGH VOLTAGE DEVICES |
| US20010033938A1 (en) * | 2000-02-11 | 2001-10-25 | Kalina Alexander I. | Method of preventing or stopping sulfuric corrosion of metals |
| WO2007144696A2 (en) * | 2005-12-30 | 2007-12-21 | Abb Research Ltd. | Method to deactivate corrosive sulfur in insulation |
Also Published As
| Publication number | Publication date |
|---|---|
| NO20151036A1 (en) | 2017-02-20 |
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