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WO1998033953A1 - Inhibition de la corrosion par l'utilisation d'une combinaison sel de pyridine quaternaire-hydrocarbure - Google Patents

Inhibition de la corrosion par l'utilisation d'une combinaison sel de pyridine quaternaire-hydrocarbure Download PDF

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Publication number
WO1998033953A1
WO1998033953A1 PCT/CA1998/000076 CA9800076W WO9833953A1 WO 1998033953 A1 WO1998033953 A1 WO 1998033953A1 CA 9800076 W CA9800076 W CA 9800076W WO 9833953 A1 WO9833953 A1 WO 9833953A1
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WO
WIPO (PCT)
Prior art keywords
pyridinium chloride
composition
surfactant
ethyl
chloride
Prior art date
Application number
PCT/CA1998/000076
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English (en)
Inventor
Neil Andrew Warrender
James R. Carlile
Original Assignee
Stanchem 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 Stanchem Inc. filed Critical Stanchem Inc.
Priority to AU58512/98A priority Critical patent/AU5851298A/en
Priority to EP98901913A priority patent/EP1015663A1/fr
Publication of WO1998033953A1 publication Critical patent/WO1998033953A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
    • C23F11/14—Nitrogen-containing compounds
    • C23F11/149—Heterocyclic compounds containing nitrogen as hetero atom
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/54—Compositions for in situ inhibition of corrosion in boreholes or wells

Definitions

  • the present invention relates to the inhibition of corrosion of iron and other metal surfaces exposed to an aqueous medium, as in the oil and gas industry.
  • this invention features the introduction of an inhibitor, including a quaternary pyridine salt in combination with a hydrocarbon, into the aqueous medium in order to bring the inhibitor into contact with the surface to be protected.
  • Chloride content (of water) 0 to 20 weight percent H 2 S partial pressure 0 to 100% of total pressure (typically 0 to 30%)
  • brine In the case of oil, brine is sometimes co-produced.
  • the brine is sometimes in the form of an emulsion, or sometimes the water forms an immiscible phase separate from the oil, depending on factors such as temperature, production pressure, pressure gradients, wellhead and pipeline velocities and the chemistries of the aqueous and oil components themselves.
  • the corrosivity of the mixture will increase with increasing water volume fraction. For a given environment, turbulence, pressure changes, high velocities and low temperatures all tend to favor emulsion formation and stabilization, while low velocities and high temperatures tend to favor phase separation of the oil and aqueous components.
  • Oil is sometimes produced in the form of a water-in-oil or oil-in-water emulsion, the resolution of which into separate immiscible phases requires heating and/or the injection of a chemical demulsifier.
  • Hard to break, or "tight'' emulsions, with high oil volume fractions and high pipeline velocities often require little or nothing in the way of chemical corrosion inhibition.
  • Gas wells can additionally produce brine independently of the water of condensation. Further, light hydrocarbons can condense throughout the well and gathering pipes, resulting in a three phase flow system which is difficult to model, understand and predict. It can still be said that the corrosivity of the aqueous phase will increase as the flow rate and pH fall, and as the chloride level and as the amount of dissolved acid gases increases.
  • CTAB cetyl trimethylammonium bromide
  • CTAB has apparently been described as able to form a bilayer on metal surfaces, and it was suggested by Shah et al. it is this ability of CTAB which is important to the observed reduction in corrosion. This interpretation by Shah et al. is consistent with their reported observation that separation of the aqueous and organic phases of the system in their Example 1 was clean, with no discoloration of either phase. As a hydrophilic surfactant, CTAB would be expected to solubilize hydrophobic elements in the aqueous layer. In other words, the cloudy appearance that would be expected to be observed if CTAB were acting as a surfactant, by forming an organic emulsion in the aqueous phase (oil-in-water), was not reported by Shah et al.
  • the corrosion rate of an iron surface exposed to an aqueous environment can be reduced by the incorporation of a quaternary pyridinium salt and an organic component into the aqueous environment.
  • incorporation of the organic component involves the formation of an emulsion by a suitable surfactant in the aqueous milieu of the system being treated.
  • a surfactant that is through a shear stabilized emulsion.
  • a first embodiment of the invention thus includes a method for inhibiting corrosion of a surface of carbon steel exposed to an aqueous medium in which the method includes forming a layer comprising a corrosion-inhibiting amount of a quaternary pyridine salt and a water- immiscible organic component on the surface by incorporating into the medium a composition containing the salt, the organic component and a surfactant.
  • the surfactant is present in the composition in an amount sufficient to solubilize a sufficient amount of the organic component in the aqueous medium so as to permit formation of the protective layer.
  • the organic component is most often a hydrocarbon and can be a single hydrocarbon, but is more likely to be a mixture of hydrocarbons.
  • the hydrocarbon can be aliphatic, aromatic or a mixture.
  • the hydrocarbon component can thus have a single boiling point or it can boil over a range.
  • the boiling range is within 70°C and 400 °C, meaning that 10% of the component is boiled off when the temperature is raised to about 70°C and about 90% of the component is boiled off when the temperature is raised to about 400°C. More typically, boiling ranges are between 100°C and 400°C, 100°C and 300°C, 150°C and 400°C, 150°C and 300°C and 150°C and 250°C.
  • a particularly preferred organic component has been found to be what is known in the industry as high boiling reformate, which is a mixture of relatively high molecular weight aromatic hydrocarbons having a boiling range of 153°C to 235°C.
  • high boiling reformate which is a mixture of relatively high molecular weight aromatic hydrocarbons having a boiling range of 153°C to 235°C.
  • Others described in specific examples below, are PCP solvent (50% recovered at 290°C and 90% recovered at 345°C) and Cyclosol 63 (10% recovered at 160°C and 90% recovered at 170°C).
  • the surfactant of the first embodiment of the invention is a hydrophilic surfactant capable of emulsifying the organic component of the mixture in the aqueous medium of the system being treated.
  • the surfactant can be cationic, non-ionic or anionic and particular surfactants are described in the description of preferred embodiments.
  • the quats of the present invention are conventional, but this is not to say that improved quats not currently known could not just as well be incorporated into the present invention.
  • the quat and hydrocarbon component can be present in the composition in a relative salt.hydrocarbon component molar proportion of from about 1 :1 to about 1 :14; 1 :2 to about 1 :14; 1 :2 to about 1 :12; 1 :4 to about 1 :9; 1 :5 to about 1 :7; or simply 1 :7.
  • These molar ratios are based on results obtained using heavy reformate, examples of which are given below. It must be borne in mind that the precise optimum ratio of particular components to be used in particular conditions varies, but instructions for the choice or components and their relative proportions are given below.
  • the hydrocarbon component can be between about 10% and 80% (by volume) of the composition, or it can between 25% and 65%, or more preferably between about 35% and 50% of the composition.
  • the amount of surfactant is between about 0.1 % and 10 % of the weight of the composition and more typically is between about 1% and 10% of the weight of the composition. It can also be between about 1% and 5%, or between about 1% and 3% of the weight of the composition.
  • the surfactant can be typically present in the composition at a level of between about 0.1 and 10% by weight of the amount of the hydrocarbon solvent, but that a level of between about 1 and 10% by weight of the amount of the hydrocarbon solvent is more likely to be preferred.
  • the pH of the medium being treated would generally be between about 3 and 7 although a pH range of between about 3.5 and 5.5 is more common.
  • the chloride content of the aqueous medium can be anywhere between about 0% and 20% by weight although content ranges between about 5% and about 15% or between 1% and 8% are more common.
  • the temperature of the aqueous medium can be between about 0°C and about 80°C, but temperatures between about 20°C and 70°C, or between about 40°C and 70°C are generally more common.
  • the system to be treated can be a pipeline, production equipment tubing, vessel, orvalving, or the like— -i.e., is of similar metallic materials exposed to similar conditions. Fluid of the system may or may not have a hydrocarbon component in addition to the aqueous component.
  • the system being treated may be a natural gas pipeline.
  • the system can include H 2 S and the partial pressure of H 2 S can be greater than about 0.1 % of the total pressure.
  • the system can include C0 2 and the partial pressure of the H 2 S can be greater than about 0.1 % of the total pressure up to about twice the partial pressure of the C0 2 .
  • the composition can also include a co-surfactant for retaining the composition as a single phase in storage prior to incorporation into the medium.
  • the co-surfactant can include an alcohol having between about 3 and about 8 carbons and can be butanol.
  • the composition can also include one or more tying agents such as nonylphenols, particularly ethoxylated nonylphenols, and/or dodecylbenzenesulphonic acid.
  • the pH could typically be adjusted to about 9, say, and the base could be, for example, an organoamine such as monoethanolamine or diethylamine.
  • compositions which are pourable at low temperatures, say down to -35°C, or even lower. It would thus be desirable for a liquid composition to be pourable over a temperature range of from about -35°C to about 50°C, but more typically, a desirable range might be from about -20°C to about +20°C.
  • a particular embodiment of the invention is thus a method for inhibiting corrosion of an iron surface exposed to an aqueous medium which includes contacting the exposed surface with a corrosion-inhibiting amount of a quaternary pyridine salt and a water-immiscible organic component by incorporating into the medium a liquid composition comprising the salt, the organic component and a surfactant, the surfactant being present in the composition in a sufficient amount to stabilize an emulsion containing the organic component in the aqueous medium.
  • Another aspect of the invention is a method for inhibiting corrosion of a surface of carbon steel exposed to a turbulent aqueous medium, the method including the step of incorporating into the medium a corrosion-inhibiting amount of a quaternary pyridine salt and a water-immiscible organic component so as to form a corrosion-inhibiting layer comprising the salt and organic component on the surface.
  • a corrosion-inhibiting amount of a quaternary pyridine salt and a water-immiscible organic component so as to form a corrosion-inhibiting layer comprising the salt and organic component on the surface.
  • compositions suitable for inhibiting corrosion of a surface of carbon steel exposed to an aqueous environment include a quaternary pyridine salt, a water-immiscible organic component and a surfactant.
  • the composition preferably also includes an agent for maintaining the composition in a single phase.
  • the agent is typically an alcohol having from about 3 to 8 carbon atoms, say butanol.
  • the organic component can be a hydrocarbon liquid, as described above.
  • the invention is a method of manufacturing an additive composition for inhibiting corrosion of a surface of carbon steel exposed to an aqueous environment, the method comprising, combining a quaternary pyridine salt, a water-immiscible organic component and a surfactant for solubilizing the organic component in the aqueous environment upon addition thereto.
  • the method can include combining an agent as part of the composition for maintaining the composition in a single phase.
  • agent can be an alcohol having from about 3 to 8 carbon atoms, say butanol.
  • the method can include combining a hydrocarbon liquid as the organic component.
  • the method can include combining into the composition other components described above.
  • Figure 1 shows inhibition of corrosion of test coupons (mgs lost) as a function of concentration (ppm) of IC10 ( ⁇ ) and Composition A (o);
  • Figure 2 shows inhibition of corrosion of test coupons (mgs lost) for a number of inhibitor formulations: 1) Composition A, without CTAB and without heavy reformate; 2) Composition B; 3) Composition B plus 5.6% heavy reformate; 4) Composition B plus 12.4% heavy reformate; 5) Composition B plus 21.4% heavy reformate; 6) Composition B plus 33.3% heavy reformate; 7) Composition B plus 50.0% heavy reformate; 8) Composition A.
  • the quat concentration was 500 ppm for all experiments;
  • Figure 3 shows inhibition of corrosion of test coupons (percent protection) observed for inhibitors containing various surfactants: 1) Composition A; 2) Composition A with an equivalent amount of CPC substituted for CTAB; 3) Composition A with an equivalent amount of LA 230 (an ethoxylated (23 mole) alcohol) substituted for CTAB; and 4) Composition A with an equivalent amount of NP-9 (an ethoxylated (9 mole) alcohol) substituted for CTAB;
  • Figure 4 shows inhibition of corrosion of test coupons (percent protection) observed for inhibitors containing various hydrocarbons: 1) Composition A with a similar concentration of xylene substituted for heavy reformate; 2) Composition A; 3) Composition A with a similar concentration of Isopar M (an aliphatic solvent boiling from about 215° to 280°C) substituted for heavy reformate; 4) Composition A with a similar concentration of PCP solvent (a blend of aromatic and aliphatic hydrocarbons) substituted for heavy reformate; and 5) Composition A with a similar concentration of Cyclosol 63 (heavy petroleum naphtha, hydrotreated) substituted for heavy reformate.
  • the overall inhibitor concentration for this series of experiments was slightly lower than that used for the experiments summarized in Figure 3;
  • Figure 5 shows inhibition of corrosion of test coupons (percent protection) as a function of the total volume of the hydrocarbon kerosene ( ⁇ l).
  • Compositions were obtained by the addition of an inhibitor having the same composition as that of Composition A, except for the presence of kerosene in place of heavy reformate; and
  • Figure 6 shows inhibition of corrosion of test coupons (percent protection) observed under static (+) and dynamic ( ⁇ ) conditions for various inhibitor formulations: 1) Composition A; 2) Composition A with NP6 substituted for CTAB; 3) Composition A with equal amounts of NP6 and CTAB substituted for the usual total amount of CTAB; and 4) Composition A with equal amounts of NP6 and NP40 substituted for the usual total amount of CTAB.
  • the quat concentration was 500 ppm for all experiments.
  • the emulsified hydrocarbon is brought into contact with the surface to be protected and is incorporated into the protective quat coating to enhance the protection afforded by the quat layer.
  • Mixtures of quats obtainable by the reaction of a pyridine and a quaternization agent such as an alkyl halide, have been used for many years as corrosion inhibitors for mild steel pipelines.
  • a typical commercial inhibitor contains 20 to 40 percent quat, and is used at an overall concentration of between about 10 and 1000 ppm.
  • the raw pyridine bases used for quaternization and blending into corrosion inhibitor formulations are generally complex mixtures and often contain hundreds of compounds.
  • a pyridine salt used as part of the present invention may be a quaternary salt obtained from a pyridine-containing composition and a compound of the formula R-X wherein R is selected from the group consisting of alkyl and aryl groups of up to about 16 carbon atoms and X is a halide. More preferably, R has up to about to about 10 or about 7 carbon atoms. R can be a benzyl group.
  • the present invention may be used as a "batch" treatment, for example to coat the internal surface of a pipe, its preferred application is as a “continuous” inhibitor.
  • the inhibitor is preferably added (as by injection at a suitable location) directly to fluid flowing through a pipeline needing protection against corrosion, injection would normally be continuous, or at least sufficiently often to maintain the minimum effective concentration in the aqueous phase, and hence the integrity of the protective layer.
  • hydrocarbon component of the present invention As far as the hydrocarbon component of the present invention is concerned, the enhanced corrosion protection has been observed with a number of different hydrocarbons.
  • high boiling aromatic materials such as heavy reformate have been found to be particularly suitable.
  • Other high-boiling, substituted benzenes of various boiling ranges that have been found to enhance corrosion protection under laboratory conditions include Cyclosol 53, 63 and PCP solvent, available from Shell Chemicals.
  • Other examples are Aromatic 100 and 150 available from Exxon.
  • Hydrocarbons tested with the commercially available quats composition known as IC10 were found to enhance the corrosion inhibition afforded by these quats. This was particularly true of those hydrocarbons having boiling points above 100°C, such as toluene and xylene, or boiling ranges which start above 100°C, such as kerosene.
  • the boiling point range of Isopar M is 215 to 280°C
  • Cyclosol 63 it is 184 to 206°C
  • PCP Solvent it is 210 to 365°C.
  • hydrocarbons having relatively high boiling points and boiling ranges are the most suitable. While it is believed that just about any hydrocarbon which meets these boiling point and boiling range criteria would offer some degree of enhanced protection, the laboratory testing described in the pertinent examples given below has identified those currently believed to be most preferable.
  • a list of potentially useful hydrocarbons are given in Table Two. This list is illustrative and not complete.
  • a useful hydrocarbon can include any petroleum naphtha, distillate, refined solvent, gas oil or extract; light or heavy; catalytic reformed, cracked, straight run or dewaxed; aromatic, naphthenic or aliphatic that successfully performs in the test outlined below. These can be used alone or in combination with each other.
  • Type III system in a pipeline carrying a multi-phase fluid attenuates, rather than enhances, the corrosion inhibiting properties of quat- based formulations.
  • the formation of a Type III microemuision depends upon the overall composition of the corrosion fluids, including the inhibitor, and the thermodynamic conditions, such as temperature, pressure and pH of the system.
  • the relative proportions of hydrocarbon, surfactant, and quat are controlled during the formulation of a corrosion inhibitor of the present invention, formation of a Type 111 system can usually be avoided.
  • the best way known to the inventors to determine the relevant parameters is by developing an active formulation using the instructions given below, which guide the selection of materials, including the hydrocarbon phase, and the choice of relative proportions.
  • Chloride content (of brine) 1 to 15 weight percent
  • H 2 S partial pressure >0.1 % of total pressure, >2x C0 2 pressure C0 2 partial pressure ⁇ 50% of total H 2 S pressure
  • the desired range of the ratio of IC10 to heavy reformate (vol/vol) is therefore between about 1 :1 and 1 :10, more preferably between 1 :3 and 1 :8, and most preferably from 1 :5 to 1 :7.
  • a surfactant which is sufficiently hydrophilic to stabilize an emulsion of the chosen hydrocarbon phase in brine is chosen for this purpose.
  • Surfactants found to be suitable include cationics, such as quatemized ammonium and pyridinium salts with a long carbon chain (>C12) alkyl substitutions; non-ionics such as those of nonylphenol-xEO series, where x is generally >6, and ethoxylated linear alcohols; and zwitterionics, such as betaines or sultaines.
  • Anionic surfactants such as sulphates, ether sulphates, sulphonates, phosphate esters and the like, have been found to produce the desired effect, but seem less likely to be as preferable because of potentially unfavorable interactions with the cationic quat component of the inhibitor.
  • Alkyl benzene sulfonates Alkyl benzene sulfonates, polymerized Alkylaryl sulfonates Alkylaryl sulfonates, polymerized
  • Alpha-sulfonated fatty acids Sulfonated fatty acids Sulfonated fatty esters Sulfonates with ether, ester or amide groups Mono & Di-ester sulfosuccinates
  • Alkyl naphthalene sulfonates Alkyl naphthalene sulfonates, polymerized Alkyl naphthalene/formaldehyde condensate polymer sulfonates Petroleum sulfonates ⁇ gnosulfonates Other sulfonates Sulfuric Acid Esters and Salts Alkyl sulfates Alcohol sulfates
  • Alcohol ether sulfates Alkyl phenol ether sulfates Fatty amide sulfates Fatty amide ether sulfates Fatty acid sulfates
  • Fatty ester sulfates Alpha-olefin Sulfates Alpha-sulfated fatty esters Natural Fat and Oil sulfates Phosphoric and Polyphosphoric Acid Esters and Salts Phosphated alkyoxylated alcohol and salts Phosphated alkyoxylated phenol and salts Other phosphoric and polyphosphoric acid esters and salts Phosphonates
  • a suitable surfactant i.e. one that will emulsify the chosen hydrocarbon phase in brine.
  • a few drops of a surfactant are added to a 10 ml sample of the intended hydrocarbon phase. If the 0.5 to 10% solution formed in this way is not cloudy, the proposed surfactant is too hydrophobic, i.e. too miscible with the hydrocarbon. Further discrimination is possible by adding a sufficient amount of the cloudy surfactant hydrocarbon mixture to a test brine, enough to form a 1 to 2% solution.
  • the emulsion which is formed on shaking should settle only slowly on standing, i.e.
  • the selected surfactant should be used at a level of between 1 and 10% (by weight) of the amount of hydrocarbon in the formulation.
  • the inhibitor as a whole i.e. the inhibitor with all components combined, have particular characteristics. It is preferable that the combined components remain in a single phase (the emulsion should be stable and the hydrocarbon should not phase separate) and remain pourable for convenient use over a wide range of temperatures, preferably as low as -35°C.
  • the inhibitor itself should not itself be corrosive to mild (carbon) steel.
  • One or more co-surfactants can thus be used to ensure that the concentrated inhibitor components remain in a single phase.
  • the preferred cosurfactants are short-chain (C3 to C8) alcohols, with butanol having been found to be particularly suitable.
  • co-surfactants A list of potentially useful co-surfactants are listed in Table Four. The choice of a co-surfactant depends on the combination of hydrocarbon, quat and surfactant used. Suitable combinations and proportions can be obtained using procedures given above. A particular co- surfactant can be used alone or in combination with one or more other co-surfactants.
  • a method to determine the exact proportions is to form a two phase mixture of the quat, surfactant and hydrocarbon phase, according to the guidelines given above, and then add the desired co-surfactant until the mixture forms a single phase at room temperature. If desired, freeze stability can then be ensured by adding progressively more co-surfactant until the single phase inhibitor concentrate does not phase separate when placed in a freezer at -35 °C for 48 hours.
  • inhibitors such as oxyalkylated nonylphenols or dodecylbenzenesulphonic acid (DDBSA) can be used as part of the inhibitor blend.
  • Amines such as monoethanolamine or diethylamine are often added to inhibitor concentrates in the amount of 2 to 5% to adjust the acidity of the formulation. It is desirable to adjust the acidity such that a 1 % concentrate of the solution (1 gm of solution added to 99 gm of water) has a pH of above 9 to ensure tolerance to the mild steel vessels in which such materials are commonly transported and stored. At more acid pH's, concentrated inhibitors can themselves be corrosive to carbon steel. The amine itself has not been observed to affect the performance of the blend.
  • additives such as solvents, co-surfactants and amines can be treated as solutes, and cease to be important in terms of performance once the inhibitor is added to a pipeline.
  • Corrosion rates can be assessed in the laboratory through the use of mild steel test coupons exposed to the corrosive conditions over a period of time.
  • the data which follow were obtained in tests in which coupons had been fashioned from a 6" wide, 0.008" thick roll of shimstock (carbon steel) by cutting it into strips approximately V- ⁇ wide.
  • a suitable volume of brine having the composition given above, was purged for four hours with a pre-blended mixture of 80% H 2 S and 20% C0 2 .
  • Each corrosion inhibitor to be tested was added, at the concentration indicated, to a 350 ml glass bottle, together with 100 ml of brine and a cleaned pre-weighed shimstock test coupon.
  • the headspace in each bottle was purged with the H 2 S/C0 2 gas mixture to remove oxygen.
  • the bottles were sealed and spun slowly for 7 days at 60°C, after which period the coupons were reclaimed, cleaned by immersion in inhibited hydrochloric acid, xylene and methanol, and then re-weighed.
  • the bottles were not spun, but were left on their sides in a stationary position.
  • weight loss from each coupon was sometimes used as a measure of the amount of corrosion of test coupons.
  • %P percent protection
  • ⁇ W is the weight loss from the coupon in milligrams
  • M is the mass of the coupon in grams
  • a second step in assessing corrosion is a visual inspection of the test coupons. Under modest magnification (say x16), localized corrosion is often apparent, even on coupons whose overall weight loss is minimal. Failure of pipelines through pitting attack is common in the industry, and an assessment of the extent and type of pitting damage on mild steel coupons is useful in determining the potential effectiveness of an inhibitor formulation.
  • An advantageous aspect of the preferred embodiment of present invention is its ability to reduce localized corrosion on test coupons under laboratory conditions. This lack of pitting has also been observed in field tests.
  • composition A The effectiveness of composition A relative to IC10 determined under laboratory conditions is illustrated by Figure 1 in which the amount of material lost from test coupons is plotted as a function of the amount of each inhibitor present in the test solution. As can be seen, at quat concentrations below 1500 ppm the inhibitor composition A is more effective than IC10 at inhibiting loss of material from test coupons. IC10 alone provides an equivalent degree of protection at a concentration of 2500 ppm of quat.
  • points 2 through 8 show the effect of varying the concentration of the heavy reformate component of Composition A on corrosion inhibition, point 1 being for the composition lacking both CTAB and heavy reformate.
  • the overall quat concentration was 500 ppm for ail of the experiments.
  • concentrations of heavy reformate between about 12 and 21% (points 4 and 5)
  • the amount of corrosion increases, but eventually corrosion inhibition is enhanced in the presence of heavy reformate (points 6 through 8).
  • the decreased protection observed at points 4 and 5 is presumably due to the formation of a Winsor Type III microemuision, as discussed above.
  • Figure 2 thus illustrates how the expected performance of an inhibitor can be established once the quat, surfactant and hydrocarbon components have been selected.
  • Figure 3 shows the effect on % protection of inhibitors containing cationic and non- ionic surfactants in place of CTAB. At similar surfactant concentration, the inhibition observed was comparable to that observed for Composition A.
  • Figure 4 shows the effect on % protection of inhibitors containing other hydrocarbon solvents in place of heavy reformate. At similar solvent concentration, the inhibition observed was comparable to that observed for Composition A. Of the hydrocarbons illustrated, both aliphatic and aromatic solvents were tested. Heavy reformate was preferred for being more readily formulated into a stable, single-phase and freeze resistant concentrate than the others.
  • Figure 5 shows the effect of the total volume of hydrocarbon, in this case kerosene, on corrosion inhibition. In other respects the inhibitor formulation was the same as Composition A. As can be seen, the degree of protection against corrosion was found to increase with increasing volume of the hydrocarbon component.
  • Figure 6 shows the performance of four inhibitor formulations, which differ in surfactant component, under "static” and “dynamic” conditions. Dynamic conditions are simply those used in all other experiments in which the test bottles were spun for the duration of the test period. In experiments described as taking place under static conditions, the test bottles were maintained in a stationary position, on their sides, for the duration of the test period. As can be seen, inhibition of corrosion was observed under both static and dynamic conditions for all of the formulations tested, although the fourth inhibitor formulation did not perform as well under static conditions.
  • NP6 was used in conjunction with a more hydrophilic surfactant, e.g. CTAB or NP40, both the dispersion of the hydrocarbon phase in the brine and the lifetime of the emulsion were improved but the observed performance did not appear to be significantly improved.
  • a more hydrophilic surfactant e.g. CTAB or NP40
  • inhibitors in accordance with the present invention to provide enhanced corrosion protection under a set of conditions selected from a broad range.
  • Ranges include temperatures between about 20°C to about 70°C; pressures between about 14 and 2100 psig, but more typically between 140 and 700 psig; and a pH between about 3 and 7, but more typically between about 3.5 and 5.5.
  • Water content may be at any level, from very "dry" pipelines containing only water of condensation to pipelines with those with larger volumes of brine and containing little or no hydrocarbon.
  • the chloride level can be up to 20% (200,000 ppm) of the aqueous layer, but more typical levels would be between about 1000 and 150,000 ppm.
  • Acid gas partial pressures may be anywhere from 0 to 100% for both H 2 S and C0 2 but they would more typically be in the range of 0 to about 20% for C0 2 and 0 to about 80% for H 2 S.
  • inhibitors of the present invention are useful include:
  • the acid gases associated with the produced hydrocarbon are extremely sour, i.e. the partial pressure of H 2 S is high with respect to both the C0 2 content (>1 :1) and the total pressure (>1%).
  • the system being treated contains significant amounts of particulate sulfur, which is known to exacerbate the corrosion of carbon steel.
  • Composition A has been tested in a gas line section under field-type conditions.
  • the section was relatively dry with a high gas velocity, significant amounts of particulate sulfur were present, and the section had an elevation change.
  • Laboratory testing indicated that conventional inhibitors would not provide adequate protection except at extremely high concentrations, but that composition A should provide corrosion protection at a treatment rate of 6000 ppm. Pitting corrosion was detected when the conventional inhibitors were used and the inhibitors were shown to be prone to gunking. Inhibitor deposits were thought responsible for some of the observed corrosion.
  • Composition A was tested on a fresh section under comparable conditions. Monitoring failed to indicate a corrosion rate above 2.8 mpy and after several months a detailed inspection of the interior showed the section treated with Composition A to be in excellent condition.
  • Protection rises gradually with concentration until a certain threshold value is reached, whereupon a further small increase improves the inhibition dramatically. At that point, further improvement in protection against corrosion usually does not occur with increasing concentration, i.e., there is a plateau in performance. It might be that there is a dynamic between adsorbed and solvated inhibitor molecules which gradually increases the surface coverage with concentration until a protective layer is formed, at which point a very significant decrease in the corrosion rate is observed.
  • an inhibitor according to the present invention that is effective at a concentration of less than 1 %, based on the volume of brine. Concentrations of thousands of ppm are usually considered high, but the current invention can be suited to relatively dry systems, making the economics reasonable. In any case, in such systems it possible to obtain inhibitors according to the present invention which are effective to a degree not possible with conventional inhibitors at comparable concentrations.
  • a principle of the current invention is to incorporate a condensed (liquid phase) hydrocarbon component into the aqueous phase of fluid material contained in a pipeline or other enclosure constructed from mild (carbon) steel, in which a quat component is used as an inhibitor against corrosion of an iron, for example, ferrous surface by the aqueous phase.
  • a quat component is used as an inhibitor against corrosion of an iron, for example, ferrous surface by the aqueous phase.
  • IC10 A blend of benzyl alkyl pyridinyl quaternary ammonium chloride (73 to 77%) and methanol (23 to 27%), available from P-Chem Inc., Latexo, Tx.
  • CTAB Cetyltrimethyl ammonium bromide
  • NP-x Nonylphenol derivatives in which x designates the number of moles of ethylene oxide incorporated in each mole of NP material. The higher the value of x, the more hydrophilic the surfactant. These non-ionic surfactants are available from Rhone-Pouienc Canada Inc., under the trade name Alkasurf NP-x
  • LA230 An ethoxylated linear alcohol containing twenty three moles of ethylene oxide per mole of alcohol. Available from Alkaril Chemicals Ltd. of Mississauga, Ontario, Canada under the trade name Alkasurf LAN-23. Composition A IC10 9.3%; CTAB 2.2%; monoethanolamine 2.1%; heavy reformate
  • composition B Composition A without any heavy reformate

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  • Life Sciences & Earth Sciences (AREA)
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  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Preventing Corrosion Or Incrustation Of Metals (AREA)

Abstract

L'invention concerne un procédé permettant d'inhiber la corrosion d'une surface d'un acier ordinaire exposée à un milieu aqueux. Selon le procédé, on forme sur ladite surface une couche qui renferme un sel de pyridine quaternaire en une quantité capable d'inhiber la corrosion et un composant organique non miscible dans l'eau, en incorporant audit milieu une composition qui renferme le sel, le composant organique et un tensioactif. Ce dernier est présent dans la composition en une quantité suffisante pour solubiliser dans le milieu aqueux une quantité suffisante du composé organique, de façon à permettre la formation de la couche de protection. Le composant organique est le plus souvent un hydrocarbure; ce peut être un hydrocarbure unique, mais c'est le plus souvent un mélange d'hydrocarbures. Le tensioactif peut être cationique, non ionique, amphotère ou anionique.
PCT/CA1998/000076 1997-02-03 1998-02-02 Inhibition de la corrosion par l'utilisation d'une combinaison sel de pyridine quaternaire-hydrocarbure WO1998033953A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU58512/98A AU5851298A (en) 1997-02-03 1998-02-02 Corrosion inhibition through the use of a quaternary pyridine salt-hydrocarbon combination
EP98901913A EP1015663A1 (fr) 1997-02-03 1998-02-02 Inhibition de la corrosion par l'utilisation d'une combinaison sel de pyridine quaternaire-hydrocarbure

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CA 2196650 CA2196650A1 (fr) 1997-02-03 1997-02-03 Inhibition de la corrosion a l'aide d'une combinaison sel quaternaire de pyridine - hydrocarbure
CA2,196,650 1997-02-03

Publications (1)

Publication Number Publication Date
WO1998033953A1 true WO1998033953A1 (fr) 1998-08-06

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Country Link
EP (1) EP1015663A1 (fr)
AU (1) AU5851298A (fr)
CA (1) CA2196650A1 (fr)
WO (1) WO1998033953A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002033216A3 (fr) * 2000-10-16 2002-08-01 Baker Hughes Inc Combinaisons inhibiteur de corrosion-reducteur de frottement
WO2020226996A1 (fr) * 2019-05-03 2020-11-12 Shell Oil Company Formulation d'inhibiteur de corrosion
US20230365814A1 (en) * 2022-05-11 2023-11-16 Saudi Arabian Oil Company Corrosion inhibitor solutions and corrosion-resistant substrates that include pyridinium hydroxyl alkyl ether compounds and methods of making the same
CN117658904A (zh) * 2023-12-05 2024-03-08 延长油田股份有限公司杏子川采油厂 一种酸化缓蚀剂、酸化工作液及其制备方法和应用

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CN109971447B (zh) * 2019-04-30 2021-01-26 濮阳市科洋化工有限公司 一种用于油井集输及污水处理系统的杀菌型缓蚀剂及其制备方法
US12065582B2 (en) 2022-05-11 2024-08-20 Saudi Arabian Oil Company Corrosion inhibitor solutions and corrosion-resistant substrates that include bis-quaternized ammonium compounds and methods of making the same
US11866666B1 (en) 2023-01-20 2024-01-09 Saudi Arabian Oil Company Methods for corrosion reduction in petroleum transportation and storage

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US4522658A (en) * 1984-06-21 1985-06-11 Halliburton Company Method and composition for protecting metal surfaces from oxidative environments
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EP0275651A1 (fr) * 1987-01-02 1988-07-27 Petrolite Corporation Composition inhibitrice de la corrosion par le dioxyde de carbone et son procédé d'utilisation
US5132093A (en) * 1988-07-29 1992-07-21 Sri International Synergistic corrosion inhibitors based on substituted pyridinium compounds
US5336441A (en) * 1991-05-29 1994-08-09 Petrolite Corporation Corrosion inhibition in highly acidic environments by use of pyridine salts in combination with certain cationic surfactants
US5368774A (en) * 1992-07-30 1994-11-29 Baker Hughes Incorporated Water soluble corrosion inhibitor effective against corrosion by carbon dioxide
EP0638663A2 (fr) * 1993-08-05 1995-02-15 Exxon Chemical Patents Inc. Inhibiteur de corrsosion intensifié et méthode d'utilisation

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US4071746A (en) * 1972-03-06 1978-01-31 Petrolite Corporation Alkylbenzyl pyridinium compounds and uses
US4672118A (en) * 1984-01-09 1987-06-09 The Dow Chemical Company N-(hydrophobe aromatic)pyridinium compounds
US4522658A (en) * 1984-06-21 1985-06-11 Halliburton Company Method and composition for protecting metal surfaces from oxidative environments
EP0275651A1 (fr) * 1987-01-02 1988-07-27 Petrolite Corporation Composition inhibitrice de la corrosion par le dioxyde de carbone et son procédé d'utilisation
US5132093A (en) * 1988-07-29 1992-07-21 Sri International Synergistic corrosion inhibitors based on substituted pyridinium compounds
US5336441A (en) * 1991-05-29 1994-08-09 Petrolite Corporation Corrosion inhibition in highly acidic environments by use of pyridine salts in combination with certain cationic surfactants
US5368774A (en) * 1992-07-30 1994-11-29 Baker Hughes Incorporated Water soluble corrosion inhibitor effective against corrosion by carbon dioxide
EP0638663A2 (fr) * 1993-08-05 1995-02-15 Exxon Chemical Patents Inc. Inhibiteur de corrsosion intensifié et méthode d'utilisation

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002033216A3 (fr) * 2000-10-16 2002-08-01 Baker Hughes Inc Combinaisons inhibiteur de corrosion-reducteur de frottement
WO2020226996A1 (fr) * 2019-05-03 2020-11-12 Shell Oil Company Formulation d'inhibiteur de corrosion
US20230365814A1 (en) * 2022-05-11 2023-11-16 Saudi Arabian Oil Company Corrosion inhibitor solutions and corrosion-resistant substrates that include pyridinium hydroxyl alkyl ether compounds and methods of making the same
WO2023219754A1 (fr) * 2022-05-11 2023-11-16 Saudi Arabian Oil Company Solutions d'inhibiteur de corrosion et substrats résistants à la corrosion qui comportent des composés d'éther alkyle-hydroxyle de pyridinium et leurs procédés de production
US12227670B2 (en) * 2022-05-11 2025-02-18 Saudi Arabian Oil Company Corrosion inhibitor solutions and corrosion-resistant substrates that include pyridinium hydroxyl alkyl ether compounds and methods of making the same
CN117658904A (zh) * 2023-12-05 2024-03-08 延长油田股份有限公司杏子川采油厂 一种酸化缓蚀剂、酸化工作液及其制备方法和应用

Also Published As

Publication number Publication date
EP1015663A1 (fr) 2000-07-05
CA2196650A1 (fr) 1998-08-03
AU5851298A (en) 1998-08-25

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