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WO2000002029A1 - Composition utilisee pour la detection de gaz electrophiles et procedes d'utilisation - Google Patents

Composition utilisee pour la detection de gaz electrophiles et procedes d'utilisation Download PDF

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Publication number
WO2000002029A1
WO2000002029A1 PCT/US1999/014937 US9914937W WO0002029A1 WO 2000002029 A1 WO2000002029 A1 WO 2000002029A1 US 9914937 W US9914937 W US 9914937W WO 0002029 A1 WO0002029 A1 WO 0002029A1
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WO
WIPO (PCT)
Prior art keywords
gas
composition
electrophilic
solvent
color
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.)
Ceased
Application number
PCT/US1999/014937
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English (en)
Inventor
Robert Verdicchio
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
R-Tec Technologies Inc
Original Assignee
R-Tec Technologies Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by R-Tec Technologies Inc filed Critical R-Tec Technologies Inc
Priority to AU48520/99A priority Critical patent/AU4852099A/en
Publication of WO2000002029A1 publication Critical patent/WO2000002029A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M3/00—Investigating fluid-tightness of structures
    • G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
    • G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
    • G01M3/20—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material

Definitions

  • An external fluorescent leak detection composition comprising sodium fluorescein and a semisynthetic cellulose thickening agent is disclosed in US 4,249,412, to Townsend, III. This patent describes the use of methyl and ethyl cellulose derivatives in such compositions. The composition is applied to a cold surface, such as refrigeration tubes.
  • Preferred thickening agents include the semisynthetic cellulose derivatives, such as carboxymethyl- cellulose, hydroxymethylcellulose, methylcellulose, ethylcellulose and mixtures thereof. This method is directed to bubble detection and not to chemical interaction with the refrigerant. Furthermore, it requires the use of a light source to excite the fluorescein.
  • compositions for the detection of an electrophilic gas such as mercaptans, suitably alkyl mercaptans, such as ethyl mercaptan which is detectable even in parts per million concentrations in natural gas, which comprises a Lewis base capable of removing a proton from the gas or reacting therewith in a similar electrophilic manner; a dye capable of visibly indicating a color change on protonation or deprotonation, that is to say on pH change; a solvent for the dye, the base and the gas; and a rheology modifier capable of producing a non-newtonian gel of all of these components which is sufficiently translucent to permit visual detection of change of color of the dye and of sufficient pseudoplasticity/ thixotropy to provide adhesion to vertical and horizontal surfaces.
  • an electrophilic gas such as mercaptans, suitably alkyl mercaptans, such as ethyl mercaptan which is detectable even in parts per million concentrations in natural gas, which comprises a Lewis
  • the Lewis base should be present in sufficient amount to bring the pH of the gel to between 6.9 and 14 and may be selected from the group consisting of alkali- and alkaline earth- metal hydroxides, alkoxides and carbonates; amines; quaternary ammonium hydroxides, alkoxyamines, hydroxylalkylamines and mixtures thereof.
  • Any indicator giving a clear transition from base to acid notably in the visible spectrum without enhancement (ie UV light) may be used.
  • the solvent is selected from the group consisting of alkanols, arylalkanols, alkyl halides, alkyl ketones, alkylamines, aralkylamines, alkyl esters of alkanoic acids, dimethylsulfoxide, water and mixtures thereof.
  • the rheology modifier prefferably be selected from the group consisting of hydroxyalkylcellulose, cellulosic semisynthetic polymers, polyvinyl alcohols, carbopols, alginates and natural gums.
  • the composition is used by providing a coating of thereof on a conduit for said gas. It has also been found useful to preserve the coating by applying to it a solution, suitably a solution comprising a sprayable film forming topcoat composition settable at between about 0 - about 30°C and a solution therefor, wherein the film is sufficiently translucent to permit visual detection of change of color of the dye.
  • compositions of the present invention for the detection of an electrophilic gas are especially useful for use with trace gases such as mercaptans, suitably alkyl mercaptans, such as ethyl mercaptan.
  • the choice of the Lewis base is a wide one.
  • alkali- and alkaline earth- metal hydroxides are sodium hydroxide and calcium or magnesium hydroxide, as alkoxides and carbonates, sodium ethoxide and sodium carbonate; as amines, quaternary ammonium hydroxides, alkoxyamines, and hydroxylalkylamines higher boiling members of this group or those having low vapor pressures at ambient temperatures are preferred.
  • Especially preferred as Lewis bases are sodium hydroxide, sodium ethoxide or methoxide, ethyl hydroxylamine and triethylamine because of their low cost and ready availability.
  • Suitable dyes used as indicators there may be mentioned: methylorange (yellow-red) thymol blue (blue to yellow); phenolphthalein (pink to clear);m-cresol purple (purple to yellow); phenol red (red to yellow); and thymolphthalein blue (blue to clear).
  • solvents such as alkanols, glycols, glycolethers, arylalkanols, alkyl halides, alkyl ketones, alkylamines, aralkylamines, alkyl esters of alkanoic acids, dimethylsulfoxide and water.
  • the alkyl moieties may be straight chain-, branch chain- and cyclic- moieties and the alkanols and alkylamines may be primary, secondary and tertiary alkanols and alkylamines.
  • the solvent is utilized in a range relative to the sum of the Lewis base and the dye of between 1 and 99 parts by volume per part by weight of base plus dye.
  • a protective coating or topcoat composition there are preferably employed ethylcellulose, polyethylene, polytetrafluorethylene or mixtures thereof epoxy resins, polyurethane resins, siloxanes, as well as natural coatings such as modified and unmodified rosin, polyvinylpyrrolidone, alkyd resins and polyacrylates and mixtures thereof.
  • Suitable solvents for the topcoat may include: aromatic hydrocarbons such as toluene, xylene, aromatic napthas, alkanes such as hexane, alkyl ketones such as methyl isobutyl ketone and acetone; straight or branched chain (C, to C 4 )alcohols such as methanol, ethanol, isopropanol and n- butanol; C, to C 5 alkyl ethers; mono-, di-, and tri- glycols (Dowanols ® manufactured by Dow Chemical Corp.); mineral spirits; mineral, vegetable, animal or marine oils ; and ⁇ or mixtures thereof.
  • aromatic hydrocarbons such as toluene, xylene, aromatic napthas, alkanes such as hexane, alkyl ketones such as methyl isobutyl ketone and acetone
  • straight or branched chain (C, to C 4 )alcohols such as methanol,
  • EXAMPLE 1 Preparation of indicator composition Thymolphthalein blue dye is added to dimethylsulfoxide (DMSO) to produce a 0.01 M solution. There is also added 0.1 ml of FD & C #5 (Yellow) per 50ml of total solution. Concentrated aqueous sodium hydroxide is added dropwise until the dye/DMSO solution has a pH of 1 1 . Sufficient hydroxyethylcellulose ( ⁇ 3g/100ml DMSO) is added to achieve a blue gel.
  • DMSO dimethylsulfoxide
  • EXAMPLE 2 Application of indicator composition All pipe contact joints and valves of a natural gas system such as the meter input and output joints are cleaned using methanol containing sufficient sodium hydroxide to provide a pH of ⁇ 10-1 1 . The blue gel is then applied to all of these pipe contact joints and valves.
  • top coat composition The gel applied as in Example 2 above, is then spray coated with an aerosol of ethylcellulose in methanol, previously similarly adjusted to pH of
  • the orange-red gel from Example 4 above is placed on a pipe surface containing a perforation of ⁇ 1 micron.
  • Example 5 The applied gel of Example 5 is coated via spraying with an aerosol consisting of polytetrafluoro-ethylene in methyl-isobutyl ketone to provide a coating of about 5-10 microns.
  • EXAMPLE 8 Preparation of another indicator composition M-Cresol purple added to dimethylsulfoxide (DMSO) to produce a 0.01 M solution. Concentrated aqueous sodium hydroxide is added dropwise until the dye/DMSO solution has a pH of 1 1 . Sufficient polyvinyl alcohol ( ⁇ 4g/100ml DMSO) is added to achieve a purple gel.
  • EXAMPLE 9 Application of indicator composition All pipe contact joints and valves of a natural gas system carrying a mercaptan tracer are cleaned using methanol containing sufficient sodium hydroxide to provide a pH of ⁇ 10-1 1 . The purple gel of Example 8 is then applied to all of these pipe contact joints and valves.
  • top coat composition The gel applied as in Example 9 above, is then spray coated with an aerosol of polyethylene in toluene, similarly previously adjusted to pH of 1 1 using dropwise addition of concentrated aqueous sodium hydroxide in methanol and the top coat thus produced is allowed to dry.
  • Phenol red added to dimethylsulfoxide (DMSO) to produce a 0.01 M solution.
  • Concentrated aqueous sodium hydroxide is added dropwise until the dye/DMSO solution has a pH of 1 1 .
  • Sufficient sodium alginate ⁇ 5g/100ml DMSO is added to achieve a red gel.
  • EXAMPLE 12 Application of indicator composition All pipe contact joints and valves of a natural gas system carrying a mercaptan tracer are cleaned using methanol containing sufficient sodium hydroxide to provide a pH of ⁇ 10-1 1 . The red gel of Example 1 1 is then applied to all of these pipe contact joints and valves.
  • EXAMPLE 13 Application of top coat composition The gel applied as in Example 9 above, is then spray coated with an aerosol of polytetrafluorethylene in toluene/methyl isobutyl ketone (solvent component ratio: 1 : 1 ), similarly adjusted to pH of 1 1 using dropwise addition of concentrated aqueous sodium hydroxide in methanol and the top coat thus produced is allowed to dry.
  • EXAMPLE 14 In accordance with the procedures of Examples 1 -13 above, but where in place of the indicator, solvent, Lewis base, rheology modifier or topcoat utilized in those examples, there are utilized any of the other members of those groups listed hereinabove, a similar result is obtained, provided of course that different indicators will show different color transformations.
  • Methyl orange is added to dimethylsulfoxide and ethyiene glycol- monobutyl ether at a solvent ratio of 1 : 1 .
  • the indicator concentration is adjusted to 0.5% hydroxyl-ethyl-ethylenediamine is added to raise the pH to 7.5% +_ .1 .
  • Hydroxypropyl-methyl-cellulose is added to achieve a concentration of 1 .0% of the rheology modifier. This result is a viscous yellow thixotropic solution of about 3000 - 5000 cps. at 21 °C.
  • Example 15 The joints of a conduit used for mercaptan containing natural gas are pre-cleaned with an alkaline methanol/isopropanol solution with a pH of 1 1 - 12. After allowing the conduit to dry, the mixture of Example 15 is applied to the joints using a brush.
  • EXAMPLE 17 The gel in Example 15 above is coated via spraying with a topcoat consisting of a film former, i.e. maleic modified rosin, in an oil based solvent consisting of linseed oil and methylethyl ketone (70/30 mixture).
  • the rosin film contains 0.5% octylphenol polyethoxy 2 ethanol as a plasticizer.
  • the result is a transparent coating which allows visual detection of the gel color change upon exposure to gas (CO 2 ).
  • EXAMPLE 18 A thixotropic viscous mixture was prepared according to Example 15 using the following components:
  • composition is pink with viscosity 50,000 cps (at 21 °C) .
  • the topcoat used to protect the thixotropic gel of Example 18 (hereafter referred to as the undercoat) has the following composition.
  • topcoat composite can be applied to the undercoat via spray (aerosol or spray-painting gun) brushed carefully, or dipped over the treated area.
  • spray aerosol or spray-painting gun
  • This coating is clear allowing visual detection of the pink gel while concurrently providing product integrity and reliability for extended periods of time.
  • Example 15 The composition of Example 15 (called the undercoat) and the composition of Example 17 (called the topcoat) was applied (after cleaning as outlined in previous examples) to a gas conduit having a known perforation (a leak) of about ⁇ 5 microns.
  • the compositions were applied to a section on the conduit which had no known perforation.
  • the perforated portion Upon passing a mercaptan containing gas through the conduit, the perforated portion turned clear while the control without perforation remained pink.
  • EXAMPLE 22 A thixotropic undercoat of the following composition was prepared according to the previous examples.
  • Example 22 The above topcoat was applied to the undercoat of Example 22 after treating a gas conduit with the latter.
  • the former produced a durable clear coating with excellent adhesion.
  • EXAMPLE 24 The topcoat of example 23 above was pressurized with solvent and propellant prior to application as follows:
  • EXAMPLE 25 APPLICATION OF INDICATOR COMPOSITION AND TOPCOAT
  • the composition of example 1 is applied to the connection inlet joint of a propane tank and coated within 5 minutes after application with the topcoat composition of example 10.
  • the coating is allowed to air dry at ambient conditions for 4-5 hours and tested for clarity and film strength.
  • the blue gel is clearly visible beneath the clear topcoat which dries to a clear hard film after 24 hours.
  • MERCAPTAN The inlet valve of the propane tank of Example 25 is cracked to allow contact of the gas with the blue undercoat gel . Upon release of the propane mercaptan gas the color changes from blue to yellow.
  • the indicator (undercoat) composition of example 5 is applied to the inlet joint in a similar manner as outlined in example 25, precleaned with a detergent composition of pHj> 10 so as not to interfere with the integrity of the indicator prior to contact with gas.
  • the indicator gel is coated with the topcoat composition of example 6 and allowed to dry. Again, after 24— hours, the detection composition was hard and clear with the orange-red indicator clearly visible.
  • Example 28 Introduction of propane gas containing 1 to 100 ppm of methyl mercaptan
  • the inlet valve of the propane tank was cracked to allow contact of the gas with the detection composition i.e. the indicator undercoat.
  • the detection composition i.e. the indicator undercoat.
  • Upon contact of the methyl mercaptan ⁇ propane gas a color change occurred changing the undercoat indicator from orange red to colorless.
  • N-Methyl pyrolidone is applied to the spent indicator system of example 28 using a brush to remove all topcoat and spent indicator. The surface is re-cleaned with alkaline detergent and a new detection system applied.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
  • Examining Or Testing Airtightness (AREA)

Abstract

L'invention concerne une composition utilisée pour la détection de gaz renfermant un gaz électrophile tenant lieu de traceur, du type mercaptan d'éthyle, avec une base de Lewis capable d'éliminer un proton à partir du gaz ou de réagir avec lui de manière électrophile analogue. La composition renferme en outre un colorant capable d'indiquer visiblement un changement de couleur sur protonation ou déprotonation; un solvant pour le colorant, la base et le gaz; et un modificateur de rhéologie capable de produire un gel non newtonien de l'ensemble des constituants considérés, suffisamment translucide pour permettre une détection visuelle du changement de couleur du colorant et présentant une pseudoplasticité/thixotropie suffisante pour assurer l'adhérence à des surfaces verticales ou horizontales.
PCT/US1999/014937 1998-07-03 1999-07-01 Composition utilisee pour la detection de gaz electrophiles et procedes d'utilisation Ceased WO2000002029A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU48520/99A AU4852099A (en) 1998-07-03 1999-07-01 Composition for the detection of electrophilic gases as tracers in other gases and methods of use thereof

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US9169698P 1998-07-03 1998-07-03
US60/091,696 1998-07-03

Publications (1)

Publication Number Publication Date
WO2000002029A1 true WO2000002029A1 (fr) 2000-01-13

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PCT/US1999/014937 Ceased WO2000002029A1 (fr) 1998-07-03 1999-07-01 Composition utilisee pour la detection de gaz electrophiles et procedes d'utilisation

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140251831A1 (en) * 2013-03-07 2014-09-11 Kenneth D. Ley LEAK DETECTION FORMULA, ANALYZER and METHODS OF USE
WO2015075197A1 (fr) 2013-11-22 2015-05-28 Degroote Jacques Méthode de marquage chimique de lots de dioxyde de carbone en vue d'en assurer la traçabilité
CN116178620A (zh) * 2023-01-10 2023-05-30 固安国勘石油技术有限公司 一种新型气敏示踪剂材料及其方法
US11953404B1 (en) * 2013-02-01 2024-04-09 Automotive Test Solutions, Inc. Composition of matter for identifying the location of a leak site

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2015829A1 (en) * 1970-04-02 1971-10-14 Accumulatorenfabnk Sonnenschein GmbH,6470 Budingen Printing dye for absorbent packing materials
US5322797A (en) * 1990-06-06 1994-06-21 Southwest Research Institute Method for detecting vapor and liquid reactants

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2015829A1 (en) * 1970-04-02 1971-10-14 Accumulatorenfabnk Sonnenschein GmbH,6470 Budingen Printing dye for absorbent packing materials
US5322797A (en) * 1990-06-06 1994-06-21 Southwest Research Institute Method for detecting vapor and liquid reactants

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11953404B1 (en) * 2013-02-01 2024-04-09 Automotive Test Solutions, Inc. Composition of matter for identifying the location of a leak site
US11959831B1 (en) 2013-02-01 2024-04-16 Automotive Test Solutions, Inc. Leak detection formula, analyze and methods of use
US20140251831A1 (en) * 2013-03-07 2014-09-11 Kenneth D. Ley LEAK DETECTION FORMULA, ANALYZER and METHODS OF USE
US10222291B2 (en) * 2013-03-07 2019-03-05 Automotive Test Solutions, Inc. Leak detection formula, analyzer and methods of use
WO2015075197A1 (fr) 2013-11-22 2015-05-28 Degroote Jacques Méthode de marquage chimique de lots de dioxyde de carbone en vue d'en assurer la traçabilité
US10408808B2 (en) 2013-11-22 2019-09-10 Jacques DEGROOTE Method of chemical marking of batches of carbon dioxide in order to ensure traceability
CN116178620A (zh) * 2023-01-10 2023-05-30 固安国勘石油技术有限公司 一种新型气敏示踪剂材料及其方法

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Publication number Publication date
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