[go: up one dir, main page]

US20050103686A1 - Method and apparatus for improving the oxidative thermal stability of distillate fuel - Google Patents

Method and apparatus for improving the oxidative thermal stability of distillate fuel Download PDF

Info

Publication number
US20050103686A1
US20050103686A1 US10/510,604 US51060404A US2005103686A1 US 20050103686 A1 US20050103686 A1 US 20050103686A1 US 51060404 A US51060404 A US 51060404A US 2005103686 A1 US2005103686 A1 US 2005103686A1
Authority
US
United States
Prior art keywords
fuel
containing heterocyclic
heterocyclic aromatic
compounds
indole
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.)
Abandoned
Application number
US10/510,604
Other languages
English (en)
Inventor
Spencer Taylor
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.)
BP Oil International Ltd
Original Assignee
BP Oil International 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
Priority claimed from GB0209624A external-priority patent/GB0209624D0/en
Priority claimed from GB0218871A external-priority patent/GB0218871D0/en
Priority claimed from GB0305551A external-priority patent/GB0305551D0/en
Application filed by BP Oil International Ltd filed Critical BP Oil International Ltd
Assigned to BP OIL INTERNATIONAL LIMITED reassignment BP OIL INTERNATIONAL LIMITED ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TAYLOR, SPENCER EDWIN
Publication of US20050103686A1 publication Critical patent/US20050103686A1/en
Priority to US11/898,716 priority Critical patent/US20080067110A1/en
Abandoned legal-status Critical Current

Links

Images

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
    • C10G25/00—Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents
    • C10G25/003—Specific sorbent material, not covered by C10G25/02 or C10G25/03
    • 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
    • C10G25/00—Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents
    • C10G25/02—Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents with ion-exchange material
    • C10G25/03—Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents with ion-exchange material with crystalline alumino-silicates, e.g. molecular sieves
    • C10G25/05—Removal of non-hydrocarbon compounds, e.g. sulfur compounds

Definitions

  • the present invention relates to methods of improving the thermal oxidative stability of a distillate fuel, to methods of determining the thermal oxidative stability of a distillate fuel and to apparatus for performing said methods.
  • thermal oxidation stability relates to the stability of the distillate jet fuel at elevated temperatures, such as in the aircraft fuel system and engine. Jet fuels need to meet certain thermal stability specifications to comply with international operational safety requirements.
  • JFTOT Jet Fuel Thermal Oxidation Tester
  • Failures in the JFTOT may result from specific deposit coloration on a heated aluminium tube surface or, less frequently, from excessive pressure resulting from the formation of filterable particulates.
  • thermal oxidative stability has been shown to vary strongly between different fuels. Although individual components have been identified as contributing to problems of stability in certain fuels in certain situations the previous results have often been contradictory or have been performed under experimental conditions or at temperatures inconsistent with the standard JFTOT test.
  • WO 91/05242 relates to a method of testing oil for unstable reactive compounds characterised by contacting at least one said reactive compound from a sample of oil with an acid catalyst to formula coloured reaction product, then relating the visible colour and/or colorimetric absorbance between 600-850 nm of this product to the presence and/or amount of unstable reactive compounds in the oil.
  • the test relies upon the oxidation of phenalenes by the oxidising agent to phenalenones and the subsequent formation of coloured indolylphenalene salts in the presence of acid.
  • Such salts are said to be generally blue to blue-violet in colour, but may vary between blue and green in the test.
  • ASTM standard UOP 276-85 entitled Pyrrole Nitrogen in Petroleum Distillates by Visible Spectroscopy is said to be a method for determining the approximate concentration of pyrroles and indoles having at least one hydrogen per carbon atom in the heterocyclic ring by visible spectroscopy.
  • the method is said to be applicable to gasolines, naphthas, kerosenes and distillate burner oils, but not applicable to crude and vacuum gas oils, which are not completely soluble in n-hexane.
  • Olefins are said to interfere with the reaction and must be removed prior to analysis. It is said that aromatic amines or aliphatic mercaptans can also interfere with the reaction.
  • the method is said to involve removal of olefins by column chromatography followed by addition of 85% phosphoric acid containing p-dimethylaminobenzaldehyde. Acetic acid is added and a deeply coloured red solution is formed. The absorbance of the coloured solution is determined spectroscopically at 540 nm and the result compared to a previously prepared calibration curve, prepared using 2-methylindole as a standard.
  • This method involves the use of both phosphoric acid and acetic acid as well as chromatographic removal of olefins.
  • a method for improving the thermal stability of a distillate fuel which comprises selectively reducing the active concentration in the fuel of N—H containing heterocyclic aromatic compounds in which the nitrogen atom of the N—H group is part of the aromatic system and wherein said fuel also contains an active concentration of metal compounds or will be exposed to active metal compounds in storage or in use.
  • a method for improving the thermal stability of a distillate fuel which comprises reducing the active concentration of metal compounds in the fuel, wherein the fuel also contains a deleterious level of N—H containing heterocyclic aromatic compounds in which the nitrogen atom of the N—H group is part of the aromatic system.
  • Deleterious level refers to a level which would have a significant effect on thermal stability as shown by deposit formation on a JFTOT test. Typically, this level will be greater than 20 mg/litre, such as greater than 50 mg/litre.
  • a method for improving the thermal stability of a distillate fuel which comprises selectively reducing the active concentration of N—H containing heterocyclic aromatic compounds in which the nitrogen atom of the N—H group is part of the aromatic system and reducing the active concentration of metal compounds present in the fuel.
  • the thermal stability of the fuel can be significantly improved by reducing the active concentration of the metal compounds, or alternatively by reducing the active concentration of the N—H containing heterocyclic aromatic compounds, or alternatively by reducing both components.
  • the thermal stability of the fuel is improved by selectively reducing the active concentration in the fuel of N—H containing heterocyclic aromatic compounds in which the nitrogen atom of the N—H group is part of the aromatic system.
  • selectively reducing as used herein is meant to reduce the active concentration of one or more of the N—H containing species in preference to reducing the concentration of other nitrogen-containing species, and, most preferably, without deliberate reduction of said other species.
  • selectively reducing pyrroles and indoles means to reduce the levels of pyrroles and indoles in preference to other N-containing species, such as pyridines, for example.
  • non-selective methods of reduction of N-containing compounds, such as hydrotreating are excluded from the method of the present invention.
  • Hydrotreating for example, reduces large numbers of N-containing and other polar compounds in a non-selective manner which can have significant effects on other properties of the fuel, such as the lubricity of the fuel.
  • Selective reduction has the advantage that the overall composition of the fuel is less significantly changed, and hence the other properties of the fuel, such as lubricity are less significantly affected by the method of the present invention.
  • hydrotreating uses a large amount of hydrogen, which has a significant cost.
  • a large amount of this hydrogen is thus utilized removing N-containing species which have relatively insignificant effects in the thermal stability of a fuel.
  • selectively reducing the species which have been found to be most deleterious according to the method of the present invention is a more efficient treatment method and avoids or at least mitigates problems with non-selective reduction methods which lead to more significant changes in the composition of the fuel.
  • the distillate fuel may be a jet fuel, avgas, diesel or gasoline.
  • the distillate fuel is a jet fuel, such as Jet-A, Jet A-1, JP-8 or F-35.
  • the deleterious N—H containing heterocyclic aromatic compounds are those in which the electrons of the nitrogen atom of the N—H group can interact with the aromatic system.
  • examples of such compounds include pyrrole, indole, pyrazole, carbazole, substituted pyrroles, indoles, pyrazoles and carbazoles, and related compounds, preferably pyrrole, indole, substituted pyrroles and substituted indoles.
  • Such nitrogen atoms, as part of the aromatic system have a significantly reduced basicity compared to conventional amines. Without wishing to be bound by theory it is believed that this property makes the ring more reactive to coupling and polymerisation type reactions, and hence makes these compounds susceptible to reactions leading to deposit formation.
  • Metals typically present in a distillate fuel may include copper, iron, lead and zinc. Typically these are present at low levels, such as in the parts per billion range (ppb).
  • the active metal compounds which it may be desirable to remove or reduce preferably comprise transition metals and, most preferably, comprise copper and/or iron compounds present in the fuel. Most preferably, the active metal compounds which it may be desirable to remove or reduce comprise copper compounds.
  • the fuel may be exposed to active metals in storage and in use.
  • the US Navy has encountered problems with copper contamination of JP-5 fuels on aircraft carriers.
  • the fuel may be exposed to any of the transition metals present in the steel and/or these metals may potentially leach in to the fuel.
  • any method for the reduction of active metal components at source may not have a significant effect after storage or in use. Methods that reduce the amount of active metals, such as copper, to which the fuel is exposed or otherwise prevent the formation of active metal species, are hence preferred.
  • problems of deposit formation are particularly an issue when the fuel is at temperature, such as just prior to combustion, for example, in nozzles.
  • the fuel can also be circulated as a coolant prior to use which may increase the extent of degradation before use.
  • the methods of the present invention comprise selectively reducing the active concentration of deleterious N—H containing heterocyclic aromatic compounds and/or the active concentration of metal compounds present in the fuel.
  • the active concentration of the deleterious N—H containing heterocyclic aromatic compounds may be selectively reduced by any known method. In one embodiment this may include physical removal of at least a portion of said compounds from the fuel, for example by treatment with a suitable adsorbent material.
  • the suitable adsorbent material is rendered selectively active towards said compounds.
  • Selective adsorption as distinct from general removal of polar species, will prolong the lifetime of the adsorption unit by increasing the time for saturation to occur. Selective adsorption may also increase the ease by which regeneration can be achieved, owing to the specific nature of the adsorbed species.
  • Selective adsorption may be obtained by surface modification of common adsorbents to tailor the adsorbent for the specific chemical species, as is known for a range of different applications.
  • selective adsorption techniques are well known from developments in chromatographic stationary phase technology and could be readily applied to removal of species according to the present invention.
  • the relatively low basicity of the deleterious N—H containing heterocyclic aromatic compounds, such as pyrroles, the active concentration of which are to be reduced in the present invention distinguish them from the more basic compounds also present in the fuel that have found to be less important in the deposit forming process.
  • Suitable adsorbent material include compounds having a benzaldehyde functionality supported on a suitable support.
  • the compound having a benzaldehyde functionality (hereinafter referred to as “benzaldehyde”) is a 4-aminobenzaldehyde. It has been found that such compounds will react with pyrroles and indoles to form a complex, thus removing the pyrroles and indoles from the fuel.
  • the 4-aminobenzaldehyde is a 4-dialkylaminobenzaldehyde.
  • the alkyl groups of the 4-dialkylaminobenzaldehyde may be the same or may be different.
  • the alkyl groups are independently selected from methyl, ethyl, propyl and butyl groups.
  • the 4-dialkylaminobenzaldehyde may be, for example, 4-methylethylaminobenzaldehyde, but preferably the alkyl groups are the same, and most preferably the 4-dialkylaminobenzaldehyde is 4-dimethylaminobenzaldehyde.
  • the suitable support is preferably selected from the group consisting of clays, carbons, aluminas, silicas and zeolites.
  • the benzaldehyde may be a 4-aminobenzaldehyde functionality which is chemically part of the suitable support, for example, is an end group or pendant group on a polymer backbone that forms the support material.
  • the support is a clay.
  • the suitable adsorbent material is thus, preferably, a surface-modified clay, which clay has been modified by addition of a benzaldehyde.
  • the surface-modified clay is prepared by adsorption on to the surface of the clay of the benzaldehyde, more preferably by adsorption of 4-dimethylaminobenzaldehyde.
  • the clay should exhibit high affinity characteristics for the benzaldehyde, such that the benzaldehyde is strongly, preferably irreversibly, adsorbed.
  • Clays with suitably high affinity for benzaldehydes may be found in a suitable handbook of clay properties, such as the “Data Handbook for Clay Minerals and Other Non-metallic Minerals”, edited by H. Van Olphen and J. J. Fripiat, and published by Pergamon Press.
  • the clay is a kaolinite, more preferably a low defect kaolinite, such as Kaolin KGa-1, available from the Clay Repository of the Clay Minerals Society.
  • the adsorbent is preferably a low defect kaolinite on which has been adsorbed 4-dimethylaminobenzaldehyde.
  • Benzaldehydes in particular 4-dialkylaminobenzaldehydes, have been found to strongly adsorb on the surfaces of kaolinite materials.
  • the benzaldehyde is preferably adsorbed to a level of at least 0.5 of a monolayer coverage, most preferably to a level of approximately 1 monolayer coverage, such as a coverage equivalent to 0.8 to 1.2 monolayers.
  • the active concentration of N—H containing heterocyclic aromatic compounds in a fuel may be reduced by contacting said fuel with the suitable adsorbent material in any known manner. This may be done, for example, by mixing the fuel and adsorbent material and subsequently separating the fuel, for example, by filtration. Alternatively, and preferably, the contacting may be achieved by passing the fuel through a suitable column containing the adsorbent material. Any suitable temperature may be used, such as 5 to 100° C., preferably ambient temperature.
  • the method of the present invention may be performed on the fuel at any suitable stage from, and including at, the refinery, during transportation or in storage of the fuel and up to, including in, the fuel system of the appropriate vehicle.
  • the method of the present invention may be performed before the fuel is hydrotreated.
  • absorbents derived from size- or shape-selective materials may be used to reduce the active concentration of the deleterious N—H containing heterocyclic aromatic compounds.
  • the reduction of the active concentration of the deleterious N—H containing heterocyclic aromatic compounds may be achieved by reacting the compounds to form species that are inactive or less active in the deposition reaction, for example by complexing the compound (including its participation as a “guest” in a molecular “host-guest” relationship), by addition of a protecting group to the N—H functionality, or by reduction of the reactivity of the compound by substitution of a substituent that makes the aromatic heterocycle less susceptible to deposit forming reactions.
  • the active concentration of the metal compounds present in the fuel may also be reduced by any known method. Suitable methods may or may not be molecularly specific in their action. In one embodiment this may include physical removal of at least a portion of said compounds from the fuel, for example by treatment such as ion exchange or by filtration through a suitable adsorbent, such as clay filtration.
  • the reduction of the active concentration of metal compounds may be achieved by reacting the compounds to form insoluble species that may be removed from the fuel or by reacting the metal compounds to form species that are inactive or less active for the deposition reaction, for example by complexing the metal compound or by adding a metal deactivator (MDA) such as a chelating agent, for example disalicylidene- 1,2-propandiamine.
  • MDA metal deactivator
  • solid-supported metal chelators can be used whereby selective adsorption of metal species can occur.
  • complexing agents or metal deactivators should be compatible with the intended use of the fuel.
  • both deleterious N—H containing heterocyclic aromatic compounds and active metal complexes may be selectively adsorbed by one supported adsorbent system comprising two specific adsorption sites. Where it is desired to reduce the active concentrations of both species this allows effectively simultaneous reduction.
  • thermal oxidative stability has previously been shown to vary strongly between different fuels and results have often been contradictory.
  • deposit formation is strongly influenced by the co-presence of both certain active metal compounds and certain N—H containing heterocyclic aromatic compounds, and that, relative to these components, certain other compounds, including other nitrogen compounds, sulphur compounds and oxygen compounds have been found to have a relatively smaller effect on deposit formation, it is possible to explain at least some of the previous variation in thermal oxidative stability results between different fuels and by different groups.
  • test method for determining the thermal stability of a distillate fuel comprises (a) contacting the distillate fuel with a solvent being at least partially immiscible with said fuel and comprising 4-aminobenzaldehyde in formic acid, to form an oil-immiscible layer and (b) relating the visible colour and/or colorimetric absorbance between 400 and 700 nm of said oil-immiscible layer to the thermal stability of the fuel.
  • the 4-aminobenzaldehyde is a 4-dialkylaminobenzaldehyde.
  • the alkyl groups of the 4-dialkylaminobenzaldehyde may be the same or may be different.
  • the alkyl groups are independently selected from methyl, ethyl, propyl and butyl groups.
  • the 4-dialkylaminobenzaldehyde may be, for example, 4-methylethylaminobenzaldehyde.
  • the alkyl groups are the same, and most preferably the 4-dialkylaminobenzaldehyde is 4-dimethylaminobenzaldehyde.
  • test method of the present invention solves the technical problem identified with prior art testing methods above, not least by providing a test which does not require the prior removal of olefins.
  • test method takes advantage of the immiscibility of formic acid with the fuel, its ability to partition the active pyrrolic and indolic compounds from the fuel, and its relatively weak acidity, such that the procedure uses fewer reagents and operations, and avoids the necessity of separating the indoles by column chromatography.
  • the colour and/or colorimetric absorbance may be related to thermal stability of the fuel by a suitable comparison.
  • the visible colour of the oil immiscible layer may be compared, by eye, with a suitable reference colour chart.
  • the colorimetric absorbance between 400 and 700nm may be measured using a suitable spectrometer to give measured absorption values at one or more values or over one or more ranges within the range 400 to 700 nm, and this value may then be compared with suitable reference data, such as absorbance values for suitable reference fuels.
  • suitable reference data may be in the form of a graph of absorbance versus concentration of particular components or may relate the absorbance directly to the thermal stability of the distillate fuel.
  • the reference fuels may be solutions comprising known concentrations of model compounds, such as indole or 2-methylindole, in hydrocarbon model fuels, such as, for example, dodecane.
  • test method of the present invention may be applied to jet fuel, avgas, diesel or gasoline distillate fuels.
  • the solvent is preferably a solution of the 4-aminobenzaldehyde in formic acid but may also comprise water, for example, a solution of 4-aminobenzaldehyde in aqueous formic acid, or mixtures with other oil-immiscible liquids.
  • the concentration of formic acid in the solvent may be at least 20% by weight, preferably at least 50% by weight.
  • the concentration of 4-aminobenzaldehyde in the solvent may be in the range 500 to 5000 mg/l, preferably 2000to 3000 mg/l .
  • the 4-aminobenzaldehyde is 4-dimethylaminobenzaldehyde, which is a commercially available compound sometimes referred to as Ehrlich's reagent.
  • test method of the present invention can be preformed using on relatively small amounts of fuel, and using relatively small amount of solvent.
  • the amount of distillate fuel used in the test method of the present invention may be in the range 2 to 25 ml, preferably in the range 5 to 10 ml.
  • the amount of solvent should be sufficient for the colour and/or colorimetric comparison, for example for colorimetric analysis, typically at least 5ml, preferably in the range 5 to 25 ml, more preferably in the range 5 to 10 ml
  • the fuel may be contacted with the solvent, preferably by mixing under agitation, such as stirring or shaking, and suitably at ambient temperature. Suitable mixing may be achieved in 5 seconds or less, but preferably mixing may be for at least 10 seconds, such as 10 to 30 seconds. Generally, shaking for 10 to 20 seconds is sufficient to achieve mixing.
  • agitation such as stirring or shaking
  • the fuel and solvent are then allowed to separate, typically for a period of at least 5 minutes, such as 5 to 30 minutes, preferably 10 to 20 minutes.
  • an apparatus comprising a kit of parts suitable for use in the test method of the present invention.
  • said apparatus comprises a first vessel containing a determined amount of solvent comprising a determined amount of 4-aminobenzaldehyde in formic acid, a measuring container suitable for measuring a determined amount of the distillate fuel, a second vessel suitable for mixing the determined amount of solvent with the determined amount of distillate fuel, and a third vessel suitable for optical analysis of the solvent phase.
  • the 4-aminobenzaldehyde is a 4-dialkylaminobenzaldehyde.
  • the alkyl groups of the 4-dialkylaminobenzaldehyde may be the same or may be different.
  • the alkyl groups are independently selected from methyl, ethyl, propyl and butyl groups.
  • the 4-dialkylaminobenzaldehyde may be, for example; 4-methylethylaminobenzaldehyde.
  • the alkyl groups are the same, and most preferably the 4-dialkylaminobenzaldehyde is 4-dimethylaminobenzaldehyde.
  • first to third vessels described in the first embodiment of the apparatus may be replaced by a single vessel.
  • first vessel containing a determined amount of solvent may also be suitable for mixing of the determined amount of solvent with the determined amount of distillate fuel, and/or may also be suitable for optical analysis of the solvent phase.
  • the vessel suitable for mixing the determined amount of solvent with the determined amount of distillate fuel is also suitable for the subsequent optical analysis of the solvent phase.
  • the first vessel preferably comprises a vial containing a specific volume of the solvent comprising a determined concentration of 4-aminobenzaldehyde in formic acid—for example 5 ml of solvent containing 3 mg of 4-dimethylaminobenzaldehyde per ml of formic acid.
  • the preferred apparatus also comprises a measuring container, such as a measuring cylinder or a suitable pipette for measuring the required amount of distillate fuel, and a stoppered container for mixing the fuel and solvent, said container also being suitable for subsequent optical analysis.
  • the stoppered container may be a stoppered cuvette suitable for mixing the fuel and solvent, which cuvette, after allowing the phases to separate and being placed in a suitable measurement device, allows the solvent phase to be directly analysed.
  • the suitable measurement device may be a colour comparator or may comprise a more sophisticated spectrophotometer which may measure absorbance at one or more specific wavelengths and/or over a given wavelength range (for example, by integration), such as, especially where the 4-aminobenzaldehyde is 4-dimethylaminobenzaldehyde, the range 530 to 570 nm.
  • the present invention also allows improvements to be made in the JFTOT test.
  • JFTOT or other thermal oxidative stability testing apparatus using one or more calibration fluids (standards) comprising the active metal compounds and/or active N—H containing heterocyclic aromatic compounds, said compounds being as defined above.
  • This calibration allows the user of the apparatus to plot the response of the JFTOT or other thermal oxidative stability apparatus to said compounds, and hence to identify the contribution of said compounds to the deposits formed in JFTOT or thermal oxidative stability tests.
  • the present invention also provides one or more calibration fluids comprising a known concentration of active N—H containing heterocyclic aromatic compounds and/or a known concentration of active metal compounds, and a hydrocarbon phase.
  • the present invention also provides a method of calibration of a thermal oxidative stability apparatus using one or more calibration fluids comprising a known concentration of active N—H containing heterocyclic aromatic compounds and/or a known concentration of active metal compounds, and a hydrocarbon phase.
  • the active N—H containing heterocyclic aromatic compounds and/or active metal compounds are as described above.
  • the thermal oxidative stability apparatus is preferably a JFTOT apparatus.
  • the hydrocarbon phase may be any suitable hydrocarbon or mixture of hydrocarbons of known composition.
  • the hydrocarbon phase is a saturated aliphatic hydrocarbon of 8 to 15 carbons atoms, for example, n-dodecane.
  • the one or more calibration fluids preferably comprise one or more fluids containing both active N—H containing heterocyclic aromatic compounds and active metal compounds, but may also comprise one or more fluids containing active N—H containing heterocyclic aromatic compounds but not containing active metal compounds and/or one or more fluids containing active metal compounds but not containing active N—H containing heterocyclic aromatic compounds.
  • a single calibration fluid may be used to produce a deposit in the thermal oxidative stability apparatus, such as in a JFTOT tube.
  • more than one calibration fluid is used, and the calibration fluids may be used to produce more than one deposit, such as a series of deposits, in the thermal oxidative stability apparatus, for example a series of deposits in JFTOT tubes with varying deposit colouration.
  • Such deposits may be used as standard responses (standards) and allow the results from unknown fuels to be compared. Where enough standards are known a calibration curve may be derived.
  • results on fuels from different thermal oxidative stability equipment can be readily compared using the results from equivalent standards run on the respective pieces of equipment.
  • the deposits formed from a calibration fluid according to the present invention may also be used to verify the performance of a thermal oxidative stability apparatus, for example, to check that the apparatus is performing within acceptable ranges and/or with required reproducibility/accuracy.
  • calibration fluids as used herein includes verification fluids comprising the active metal compounds and/or active N—H containing heterocyclic aromatic compounds
  • the method of calibration according to the present invention includes verification of the performance of the thermal oxidative stability apparatus using one or more verification fluids.
  • the calibration fluids may be run individually to create such standards and/or may be mixed with other such calibration fluids and/or with fuels.
  • the mixture of two calibration fluids in a known combination will give a third calibration fluid of known composition.
  • an unknown fuel may be combined (or doped) with a known quantity of a calibration fluid, and the results from the doped fuel compared to the undoped fuel (and, optionally, with standards).
  • the calibration fluids preferably have an active N—H containing heterocyclic aromatic compound content, for example 2-methylindole, pyrrole and/or 2,5-dimethylpyrrole content, of from 0 to 250 mg/l.
  • the calibration fluids preferably have an active metal compounds content, for example a copper(II) ion content, of from 0 to 100 ppb.
  • the calibration fluids may also be used as calibration fluids for other types of thermal oxidative stability tests, such as the test method of the fourth aspect of the present invention.
  • FIG. 1 shows results from JFTOT screening of different compounds in Jet A-1 (J1) at 270 and 280° C. on aluminium JFTOT tubes.
  • FIG. 2 shows a comparison between deposition tendencies for J1 jet fuel and dodecane containing 250 mg1 ⁇ 1 2-methylindole as a function of JFTOT test temperature.
  • FIG. 3 shows JFTOT tube profiles showing the effect of different copper (II) concentrations in dodecane on deposit formation in the presence of 250 mg1 ⁇ 1 2-methylindole at 260° C.
  • FIG. 4 shows aluminium JFTOT tube profiles showing the deposition occurring in dodecane containing 100 ppb Cu II and 250 mg1 ⁇ 1 thianaphthene at 260 and 340° C.
  • FIG. 5 shows aluminium JFTOT tube profiles showing the deposition occurring in dodecane containing different concentrations (indicated) of collidine and copper(II) at 260° C.
  • FIG. 6 shows the dependence of JFTOT deposit volume on copper(II) concentration in the presence of pyrrole and 2,5-dimethylpyrrole using aluminium tubes at 260° C.
  • FIG. 7 shows the effect of a metal deactivator (6 mg1 ⁇ 1 ) on deposition produced from dodecane in the 2-methylindole (250 mg1 ⁇ 1 )/100 ppb copper(II) system (aluminium tubes).
  • FIG. 8 shows stainless steel JFTOT tube deposit profiles showing the deposition occurring in dodecane containing 2-methylindole (250 mg1 ⁇ 1 ) and different copper(II) concentrations at 260° C.
  • FIG. 9 shows the effect of a metal deactivator on deposition produced from dodecane in the 2-methylindole (250 mg1 ⁇ 1 )/100 ppb copper(II) system (stainless steel tubes).
  • FIG. 10 shows a calibration plot showing absorbance at 545 nm of formic acid/DMAB solutions as a function of 2-methylindole concentration in dodecane.
  • FIG. 11 shows the UV-Visible spectra for formic acid/DMAB solutions of extracts from three jet fuels.
  • n-Dodecane (ex Aldrich) was used as the model hydrocarbon phase for the JFTOT studies. Samples of a jet fuel (Jet A-1, ex Coryton Refinery) with a breakpoint of 270° C. were also used in several of the tests.
  • pyrrole 2,5-dimethylpyrrole, indole, 2-methylindole, 3-methylindole, 2-methylindoline, 2,4,6-trimethylpyridine, 3-methylquinoline, thianaphthene, benzofuran and indene.
  • JFTOT tests were conducted, unless stated otherwise, under standard ASTM D3241 conditions, although temperature was varied in some tests. Standard 6061 aluminium and 316 stainless steel tubes were purchased from the manufacturer, Alcor.
  • Deposition levels were quantified using an ellipsometric technique as described in C Baker, P David, S E Taylor and A J Woodward, Proceedings of the 5 th International Conference on Stability and Handling of Liquid Fuels, Rotterdam, 433-447 (1995) which is herein incorporated by reference.
  • Deposit thickness measurements were made over the tube surface at regular intervals using a Philips “Fuel Qualifier” instrument, and the deposit volumes determined by integrating the thickness results. This approach was applied to both types of tube, after inputting the pre-determined baseline parameters for aluminium and stainless steel.
  • FIG. 2 shows the data for 2-methylindole, which exhibited the highest deposit-forming tendency when tested in J1.
  • Thianaphthene, benzofuran and indene were also tested in an identical manner. However these substrates all showed low deposit volumes with no significant change in the deposition tendencies for these substrates in the presence of copper, compared with its absence. These results show that these non-N—H containing aromatic compounds do not give significant deposit formation.
  • FIG. 4 shows this for dodecane containing 100 ppb copper(II) and 250 mg1 ⁇ 1 of thianaphthene at two temperatures.
  • FIG. 5 shows the effect of different concentrations of collidine (2,4,6-trimethylpyridine) and copper(II) on deposit formation from dodecane on aluminium at 260° C.
  • the deposit formation was seen to be relatively low.
  • the same effect was found for 3-methylquinoline. This behaviour was also found to be consistent with its behaviour in J1 fuel.
  • FIG. 7 shows the effect of addition of a metal deactivator (disalicylidene-1,2-propandiamine), in the case of the 2-methylindole system. It can be seen from FIG. 7 that the use of a metal deactivator reduces the formation of deposits. FIG. 7 thus illustrates a method of improving the thermal stability of the fuel (reducing deposit formation) by reducing the active concentration of metal compounds in the fuel, according to one aspect of this invention.
  • a metal deactivator diisalicylidene-1,2-propandiamine
  • FIG. 8 contains deposit profiles for JFTOT tests carried out on 2-methylindole (250 mg1 ⁇ 1 ) in the presence different copper(II) concentrations. It can be seen that the deposit formation is less dependent on the presence of copper on stainless steel than found for aluminium tubes in FIG. 3 , and deposits are seen even in the absence of added copper for 2-methylindole.
  • the total deposit levels with 100 ppb copper in dodecane containing 2-methylindole (250 mg1 ⁇ 1 ) are similar on both aluminium tubes and stainless steel tubes under these conditions.
  • FIG. 9 shows the effect of addition of a metal deactivator (disalicylidene-1,2-propanediamine), in the case of the 2-methylindole system on stainless steel. Again the use of a metal deactivator reduces the formation of deposits.
  • a metal deactivator diisalicylidene-1,2-propanediamine
  • the following examples illustrates the production of a calibration fluid comprising active N—H containing heterocyclic aromatic compounds and/or active metal compounds, and the use of such a fluid to calibrate a thermal oxidative stability apparatus.
  • the method of preparation of the calibration fluid is similar to that used to prepare the solutions described in the Examples above.
  • CN copper naphthenate
  • CN copper naphthenate
  • the resultant mixture was then be subjected to testing in a JFTOT under ASTM D3241 conditions at 260° C.
  • the deposit thus formed may be used as a standard and compared to deposits obtained from jet fuels in the same apparatus or may be used to verify the performance of the apparatus.
  • the volume of deposit resulting from this test using the calibration fluid as described above should be in the range 1 to 2 ⁇ 10 ⁇ 5 cm 3 , corresponding approximately to a “3” visual colour rating on the ASTM D3241 scale.
  • FIG. 3 shows a series of deposits formed at varying concentrations of copper (II) compounds in a model fuel with 250 mg/l of 2-methyindole. These could form a series of standard deposits, as described above, for the particular JFTOT apparatus and conditions. An unknown fuel could be tested on the same apparatus and under the same conditions and compared to these deposit profiles. The calibration data could be used to derive the level of deposit forming compounds in the fuel.
  • II copper
  • one or more calibration fluids equivalent to the calibration fluids used to generate the standard deposits could be run in the JFTOT to form further deposits, which can be compared to the standard deposits expected to verify the performance of the JFTOT apparatus is as expected.
  • FIG. 8 shows a similar series of deposits formed under different conditions (in this case with a different JFTOT tube), which could be used to compare an unknown fuel tested under these different conditions.
  • JFTOT Jet Fuel Thermal Oxidation Tester
  • the jet fuels were treated in the same manner, and their UV-Visible spectra determined using a Cary 50 spectrophotometer.
  • the absorbance at 545 nm was used to determine the concentration of indoles in the sample (expressed as “2-methylindole equivalent concentration”).
  • FIG. 11 shows the UV-Visible spectra for the three jet fuels. From these absorbance data, the equivalent indole concentrations given in Table 1 are obtained. Two different methods, giving the same relative results are compared in Table 1. In the first, the absorbance readings at a single wavelength (545 nm) are compared with the standard values for 2-methylindole. Other indoles could be selected for this comparison.
  • an integrated absorption intensity is selected as a criterion, opening up the possibility that substituent effect in the indole structure may change the position of maximum absorption.
  • a calibration equivalent to that given in FIG. 10 , but for indole itself, leads to the analysed data in Table 1, columns 4 and 6.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
  • Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
US10/510,604 2002-04-26 2003-04-24 Method and apparatus for improving the oxidative thermal stability of distillate fuel Abandoned US20050103686A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US11/898,716 US20080067110A1 (en) 2002-04-26 2007-09-14 Method and apparatus for improving the oxidative thermal stability of distillate fuel

Applications Claiming Priority (7)

Application Number Priority Date Filing Date Title
GB0209624.6 2002-04-26
GB0209624A GB0209624D0 (en) 2002-04-26 2002-04-26 Method
GB0218871A GB0218871D0 (en) 2002-08-13 2002-08-13 Method
GB0218871.2 2002-08-13
GB0305551A GB0305551D0 (en) 2003-03-11 2003-03-11 Method and apparatus
GB0305551.4 2003-03-11
PCT/GB2003/001752 WO2003091361A2 (en) 2002-04-26 2003-04-24 Method and apparatus for improving the oxidative thermal stability of distillate fuel

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US11/898,716 Continuation US20080067110A1 (en) 2002-04-26 2007-09-14 Method and apparatus for improving the oxidative thermal stability of distillate fuel

Publications (1)

Publication Number Publication Date
US20050103686A1 true US20050103686A1 (en) 2005-05-19

Family

ID=29273345

Family Applications (2)

Application Number Title Priority Date Filing Date
US10/510,604 Abandoned US20050103686A1 (en) 2002-04-26 2003-04-24 Method and apparatus for improving the oxidative thermal stability of distillate fuel
US11/898,716 Abandoned US20080067110A1 (en) 2002-04-26 2007-09-14 Method and apparatus for improving the oxidative thermal stability of distillate fuel

Family Applications After (1)

Application Number Title Priority Date Filing Date
US11/898,716 Abandoned US20080067110A1 (en) 2002-04-26 2007-09-14 Method and apparatus for improving the oxidative thermal stability of distillate fuel

Country Status (8)

Country Link
US (2) US20050103686A1 (zh)
EP (1) EP1499698A2 (zh)
JP (1) JP2005529197A (zh)
CN (1) CN1329485C (zh)
AU (1) AU2003227877A1 (zh)
CA (1) CA2483300A1 (zh)
NZ (1) NZ535892A (zh)
WO (1) WO2003091361A2 (zh)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140076776A1 (en) * 2012-09-17 2014-03-20 Exxonmobil Research And Engineering Company Characterization of pre-refined crude distillate fractions
US20200181515A1 (en) * 2018-12-07 2020-06-11 Exxonmobil Research And Engineering Company Fuel high temperature antioxidant additive
US11136516B2 (en) 2018-12-07 2021-10-05 Exxonmobil Research And Engineering Company Motor gasoline with improved octane and method of use

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8249816B2 (en) * 2004-02-13 2012-08-21 Chevron Oronite Company, Llc High throughput screening methods for fuel compositions
JP2006199783A (ja) * 2005-01-19 2006-08-03 Japan Energy Corp 燃料組成物
US9028675B2 (en) 2011-07-07 2015-05-12 Exxonmobil Research And Engineering Company Method for increasing thermal stability of a fuel composition using a solid phosphoric acid catalyst
CA2869038A1 (en) * 2012-04-03 2013-10-10 Tyco Electronics Raychem Bvba Telecommunications enclosure and organizer
EP3619285A1 (en) * 2017-05-01 2020-03-11 ExxonMobil Research and Engineering Company Jet fuel treating for blending compatibility

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2139943A (en) * 1934-07-13 1938-12-13 Pennsylvania Petroleum Res Cor Process and apparatus for treating mineral oils
US2181122A (en) * 1937-12-29 1939-11-28 Du Pont Stabilization of organic substances
US2181121A (en) * 1937-12-29 1939-11-28 Du Pont Stabilization of organic substances
US2353690A (en) * 1942-11-11 1944-07-18 Du Pont Stabilization of organic substances
US2361339A (en) * 1940-06-08 1944-10-24 Sheil Dev Company Metal deactivators
US2584784A (en) * 1949-05-21 1952-02-05 Du Pont Salts of 1-salicylalaminoguanidine
US2763603A (en) * 1951-01-12 1956-09-18 Union Oil Co Preparation and use of specific adsorbents
US3446729A (en) * 1966-11-02 1969-05-27 Gulf Research Development Co Process for removing sulfur,oxygen and nitrogen compounds from petroleum distillates
US4203725A (en) * 1978-02-13 1980-05-20 Contamoil Corporation Method and test kit for the on-site determination of the presence of contaminant material in lubricating oil
US4298472A (en) * 1979-03-13 1981-11-03 Institut Francais Du Petrole Process for manufacturing impregnated silicas and the use of these silicas for analysis or purification of industrial products
US4409092A (en) * 1980-04-07 1983-10-11 Ashland Oil, Inc. Combination process for upgrading oil products of coal, shale oil and crude oil to produce jet fuels, diesel fuels and gasoline
US4529504A (en) * 1983-02-10 1985-07-16 Canadian Patents And Development Limited-Societe Canadienne Des Brevets Et D'exploitation Limitee Removal of nitrogenous compounds from petroleum processing products using chlorosilylated silica gel
US5807413A (en) * 1996-08-02 1998-09-15 Exxon Research And Engineering Company Synthetic diesel fuel with reduced particulate matter emissions
US6150575A (en) * 1998-11-12 2000-11-21 Mobil Oil Corporation Diesel fuel

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3491020A (en) * 1967-02-14 1970-01-20 Gulf Research Development Co Sweetening process utilizing a catalyst composite with available lattice oxygen
DE69032444T2 (de) * 1989-09-27 1998-11-26 The Commonwealth Of Australia, Canberra Verfahren zum testen von öl
JPH04252952A (ja) * 1991-01-29 1992-09-08 Shirado Kagaku:Kk ガソリン中のメチール・ターシャリ・ブチールエーテルの定量分析法
DE4424712A1 (de) * 1994-07-13 1996-01-18 Basf Ag Verwendung von Benzaldehyden zum Markieren von Kohlenwasserstoffen
CN1215148C (zh) * 2000-06-16 2005-08-17 北京三聚环保新材料有限公司 脱除液化石油气所含有机硫的方法
CN1132900C (zh) * 2000-07-21 2003-12-31 石油大学(北京) 一种液态烃硫化氢脱除剂的制备方法及其再生方法
US20030110684A1 (en) * 2001-12-18 2003-06-19 Henly Timothy J. Extremely stable diesel fuel compositions

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2139943A (en) * 1934-07-13 1938-12-13 Pennsylvania Petroleum Res Cor Process and apparatus for treating mineral oils
US2181122A (en) * 1937-12-29 1939-11-28 Du Pont Stabilization of organic substances
US2181121A (en) * 1937-12-29 1939-11-28 Du Pont Stabilization of organic substances
US2361339A (en) * 1940-06-08 1944-10-24 Sheil Dev Company Metal deactivators
US2353690A (en) * 1942-11-11 1944-07-18 Du Pont Stabilization of organic substances
US2584784A (en) * 1949-05-21 1952-02-05 Du Pont Salts of 1-salicylalaminoguanidine
US2763603A (en) * 1951-01-12 1956-09-18 Union Oil Co Preparation and use of specific adsorbents
US3446729A (en) * 1966-11-02 1969-05-27 Gulf Research Development Co Process for removing sulfur,oxygen and nitrogen compounds from petroleum distillates
US4203725A (en) * 1978-02-13 1980-05-20 Contamoil Corporation Method and test kit for the on-site determination of the presence of contaminant material in lubricating oil
US4298472A (en) * 1979-03-13 1981-11-03 Institut Francais Du Petrole Process for manufacturing impregnated silicas and the use of these silicas for analysis or purification of industrial products
US4409092A (en) * 1980-04-07 1983-10-11 Ashland Oil, Inc. Combination process for upgrading oil products of coal, shale oil and crude oil to produce jet fuels, diesel fuels and gasoline
US4529504A (en) * 1983-02-10 1985-07-16 Canadian Patents And Development Limited-Societe Canadienne Des Brevets Et D'exploitation Limitee Removal of nitrogenous compounds from petroleum processing products using chlorosilylated silica gel
US5807413A (en) * 1996-08-02 1998-09-15 Exxon Research And Engineering Company Synthetic diesel fuel with reduced particulate matter emissions
US6150575A (en) * 1998-11-12 2000-11-21 Mobil Oil Corporation Diesel fuel

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140076776A1 (en) * 2012-09-17 2014-03-20 Exxonmobil Research And Engineering Company Characterization of pre-refined crude distillate fractions
US9394497B2 (en) * 2012-09-17 2016-07-19 Exxonmobil Research And Engineering Company Characterization of pre-refined crude distillate fractions
US20160319208A1 (en) * 2012-09-17 2016-11-03 Exxonmobil Research And Engineering Company Characterization of pre-refined crude distillate fractions
US10676684B2 (en) * 2012-09-17 2020-06-09 Exxonmobil Research And Engineering Company Characterization of pre-refined crude distillate fractions
US20200181515A1 (en) * 2018-12-07 2020-06-11 Exxonmobil Research And Engineering Company Fuel high temperature antioxidant additive
US10808194B2 (en) * 2018-12-07 2020-10-20 Exxonmobil Research And Engineering Company Fuel high temperature antioxidant additive
US11136516B2 (en) 2018-12-07 2021-10-05 Exxonmobil Research And Engineering Company Motor gasoline with improved octane and method of use

Also Published As

Publication number Publication date
CA2483300A1 (en) 2003-11-06
WO2003091361A2 (en) 2003-11-06
EP1499698A2 (en) 2005-01-26
CN1649985A (zh) 2005-08-03
NZ535892A (en) 2006-11-30
JP2005529197A (ja) 2005-09-29
CN1329485C (zh) 2007-08-01
WO2003091361A3 (en) 2004-03-04
US20080067110A1 (en) 2008-03-20
AU2003227877A1 (en) 2003-11-10

Similar Documents

Publication Publication Date Title
US20080067110A1 (en) Method and apparatus for improving the oxidative thermal stability of distillate fuel
Smith et al. Crude oil polar chemical composition derived from FT− ICR mass spectrometry accounts for asphaltene inhibitor specificity
US20080190354A1 (en) Detection system
Reynolds Characterization of Heavy Residua by Aapplication of a Modified D 2007 Separation and Electron Paramagnetic Resonance
Romanczyk et al. Examination of two-dimensional gas chromatography with a nitrogen chemiluminescence detector to facilitate quantitation and characterization of nitrogen-containing compounds in petroleum-derived fuels
Morris et al. The effects of stabilizer additives on the thermal stability of jet fuel
da Cunha et al. Determination of nitrogen-containing polycyclic aromatic compounds in diesel and gas oil by reverse-phase high performance liquid chromatography using introduction of sample as detergentless microemulsion
Flego et al. N-containing species in crude oil fractions: An identification and quantification method by comprehensive two-dimensional gas chromatography coupled with quadrupole mass spectrometry
KR101585323B1 (ko) 수소/중수소 교환 및 질량 분광법을 이용한 혼합물 중 질소화합물의 분석방법
de Aguiar et al. Chemometric Analysis Combined with GC× GC-FID and ESI HR-MS to Evaluate Ultralow-Sulfur Diesel Stability
Singh et al. A comparative evaluation of nitrogen compounds in petroleum distillates
Nagpal et al. Stability of cracked naphthas from thermal and catalytic processes and their additive response. Part II. Composition and effect of olefinic structures
US4783416A (en) Analytical method to determine the unwashed gum content in a gasoline boiling hydrocarbon
Morris et al. Influences exerted by metal deactivator on the thermal stability of aviation fuel in the presence of copper
EP0570363B1 (en) Method of testing oils
CA3059368A1 (en) Jet fuel treating for blending compatibility
Reynolds Metals and heteroatoms in heavy crude oils
Hilden The relationship of gasoline diolefin content to deposits in multiport fuel injectors
Pereira et al. Sustainable aviation fuel: Impact of alkene concentration on jet fuel thermal oxidative test (JFTOT)
Nizami Chemical aspects of thermal instability in jet fuels from Saudi-Arabian crude oils
JP5205642B2 (ja) 燃料油組成物
Hazlett et al. The Chemistry of deposit formation in distillate fuels
EP2666009A1 (en) Test kit and method for detection of additives in fuel compositions
Dorris Additives for middle distillate and kerosine fuels
AU2012208486A1 (en) Test kit and method for detection of additives in fuel compositions

Legal Events

Date Code Title Description
AS Assignment

Owner name: BP OIL INTERNATIONAL LIMITED, ENGLAND

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TAYLOR, SPENCER EDWIN;REEL/FRAME:016294/0471

Effective date: 20041007

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE