WO2002046496A2 - Corrosion inhibition using aerosols - Google Patents

Corrosion inhibition using aerosols Download PDF

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Publication number
WO2002046496A2
WO2002046496A2 PCT/EP2001/013786 EP0113786W WO0246496A2 WO 2002046496 A2 WO2002046496 A2 WO 2002046496A2 EP 0113786 W EP0113786 W EP 0113786W WO 0246496 A2 WO0246496 A2 WO 0246496A2
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corrosion
corrosion inhibitors
acid
salts
moist
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PCT/EP2001/013786
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German (de)
French (fr)
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WO2002046496A3 (en
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Steffen RÜSSE
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Henkel Kommanditgesellschaft Auf Aktien
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Publication of WO2002046496A3 publication Critical patent/WO2002046496A3/en

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    • 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
    • C23F11/02—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in air or gases by adding vapour phase inhibitors

Definitions

  • the invention relates to a method for inhibiting corrosion of metallic surfaces which are brought into contact with moist gases.
  • metallic surfaces can be found, for example, in exhaust air ducts from companies in which aqueous media are moved and / or sprayed with high turbulence and at the same time a gas, for example air, is pumped or sucked through the system.
  • a special, but not limiting example of this is painting systems, for example in vehicle construction. In such systems, paint overspray is washed out of the exhaust air by water.
  • the resulting exhaust air is a stream of a moist gas, which contains water at least in gaseous form, but usually also in the form of an aerosol.
  • the stream of the moist gas contains inorganic salts and possibly organic components that are carried along with the aerosol. These inorganic salts and possibly organic components are deposited on the surfaces of the exhaust air ducts. Together with the dampness which is also deposited, they can cause corrosion damage, as will be described in more detail below.
  • the object of the invention is to provide an effective method for controlling the corrosion of metal surfaces which are in contact with a moist gas.
  • the invention relates to a method for inhibiting corrosion of metallic surfaces that come into contact with moist gases are brought, with the moist gases being added corrosion inhibitors in the form of an aerosol.
  • the moist gases are generally an exhaust air stream which contains water in gaseous form and / or in the form of an aerosol.
  • Such a moist exhaust air flow generally occurs when air is pumped or sucked through a system in which water is kept in turbulent motion and / or sprayed. For example, this occurs in gas scrubbers in which contaminants are to be removed from a gas stream by sprayed water.
  • Another example are exhaust air ducts from paint shops, where paint particles in the exhaust air are washed out by water.
  • the metallic surfaces can be selected, for example, from steel, zinc, galvanized steel or aluminum. Alloys of the metals mentioned are also included. Steel is in particular stainless steel, for example type 1.4301. The method is particularly suitable for use on metallic surfaces of exhaust air ducts in paint shops.
  • the corrosion inhibitors in the form of an aerosol can be added to the moist gas stream (exhaust air stream) shortly before or in the ventilator itself.
  • the anti-corrosion agent is entrained and reaches precisely those problem areas where corrosion by salting takes place.
  • the corrosion inhibitors are preferably added to the gas stream in the form of an aqueous solution or dispersion and suitable measures are taken to ensure that droplets of this aqueous solution and / or dispersion in the form of an aerosol are entrained in the moist gas stream. This can be achieved, for example, by spraying or injecting the solution or dispersion of the corrosion inhibitors into the gas stream continuously or discontinuously.
  • the corrosion inhibitors can be selected from a) polymeric amino acids, in particular polyaspartic acid, or their salts, b) carboxylic acids with 6 to 24, in particular with 6 to 9 C atoms, or their salts, c) organic amines, in particular alkanolamines, or their Salts, d) metal compounds, in particular compounds of zinc, molybdenum and / or tungsten, the latter two preferably in oxidation state VI, e) polymeric carboxylic acids other than polyamino acids, in particular polymers or copolymers of acrylic acid, methacrylic acid, maleic acid and partially saponified polyacrylamides, or in each case their salts, f) organic phosphonic acids, in particular geminal diphosphonic acids and phosphonocarboxylic acids such as, for example, 1-hydroxye
  • Suitable corrosion inhibitors of group b) are, for example, carboxylic acids of the formula (I)
  • Ph-COCH CH group
  • R ⁇ is a linear or branched alkyl radical having 8 to 18 carbon atoms and Ph is a phenyl group.
  • Typical examples are the fatty acids caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, palmoleic acid, stearic acid, isostearic acid, oleic acid, elaidic acid, petroselinic acid, linoleic acid, linolenic acid, elaeostearic acid, arachidic acid, gadoleic acid, arachidonic acid, behenic acid Erucic acid and clupanodonic acid as well as their technical mixtures, such as those that occur in the pressure splitting of natural fats and oils.
  • Carboxylic acids of the formula (I) are preferably used in which R 3 represents alkyl radicals having 5 to 17 and in particular having 5 to 8 carbon atoms.
  • substituted carboxylic acids examples include in the group of alkylbenzoylacrylic acids.
  • An example is 3- (p-1)
  • Anionic surfactants of the petroleum sulfonate type can be considered as group g) of corrosion inhibitors. These are sulfoxidation products of paraffin fractions with an average of 6 to 30, in particular 10 to 20, carbon atoms.
  • the petroleum sulfonates can also be regarded as secondary alkane sulfonates, with alkali or alkaline earth metals, ammonium or alkylammonium being suitable as counterions.
  • the petroleum sulfonates are preferably used in the form of their sodium or calcium salts.
  • the corrosion inhibitors of the individual groups can be combined with one another, for example group b) with group c) or group d) with group e) and / or group f).
  • Corrosion inhibitors which are Brönstedt acids, are preferably used in the form of their water-soluble salts, in particular in the form of alkali metal or amine salts.
  • the pH of the aqueous solution or dispersion of the corrosion inhibitors is in the particularly effective range from about 7 to about 10.
  • Spreading agents are preferably added to the moist gas as an aerosol. This can be done together with the addition of the corrosion inhibitors, but also separately from these.
  • Surfactants such as surfactants are particularly suitable as spreading agents. These spreading agents are also deposited on the metallic surfaces and reduce the surface tension of the moisture film on these surfaces. As a result, the corrosion inhibitors get into gaps more easily and can easily infiltrate old deposits. In addition, these spreading agents have a cleaning effect, so that regular cleaning operations are facilitated.
  • Alkalinity carriers can also be added to the moist gas, which preferably also takes the form of an aerosol.
  • the effect of the alkalinity carriers is that the acids formed on the metallic surfaces by biodegradation of entrained organic substances are neutralized. The corrosion effect of such acids is therefore reduced.
  • the alkalinity carriers can generally be alkalis such as sodium hydroxide.
  • alkaline carriers are preferred, which in turn contribute to the corrosion protection effect. Examples of such alkalinity carriers are soaps and organic amines, especially alkanolamines.
  • the corrosion inhibitors are preferably added to the moist gas in an amount such as an aerosol that one m 3 of the moist gas, for example the exhaust air, contains 1 ⁇ g to 10 mg, preferably 10 ⁇ g to 1 mg, corrosion inhibitor.
  • the aqueous solution or dispersion of the corrosion inhibitors, which are added as aerosols to the moist gas preferably contains the corrosion inhibitors in a concentration of 0.1 to 20% by weight, in particular 1 to 5% by weight.
  • the method according to the invention effectively reduces the corrosion problems described at the outset on metallic surfaces which are in contact with moist gases. This extends the intervals for maintenance measures or the renewal of the systems and thereby increases their efficiency.

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

Abstract

The invention relates to a method for inhibiting the corrosion of metallic surfaces, which come into contact with humid gases. The method consists of adding corrosion inhibitors to the humid gases in the form of an aerosol. The metallic surfaces are preferably extractor ducts of spray booths.

Description

"Korrosionsinhibierung durch Aerosole""Corrosion inhibition by aerosols"
Die Erfindung betrifft ein Verfahren zur Korrosionsinhibierung metallischer Oberflächen, die mit feuchten Gasen in Kontakt gebracht werden. Solche metallischen Oberflächen finden sich beispielsweise in Abluftkanälen von Betrieben, in denen wäßrige Medien mit hoher Turbulenz bewegt und/oder versprüht werden und gleichzeitig ein Gas, beispielsweise Luft, durch die Anlage gepumpt oder gesaugt wird. Ein spezielles, jedoch nicht begrenzendes, Beispiel hierfür sind Lackieranlagen, beispielsweise im Fahrzeugbau. In derartigen Anlagen wird Lackoverspray durch Wasser aus der Abluft ausgewaschen. Die dabei entstehende Abluft stellt einen Strom eines feuchten Gases dar, das Wasser zumindest in Gasform, in der Regel jedoch auch in Form eines Aerosols enthält. Außer dem Wasser enthält der Strom des feuchten Gases anorganische Salze und ggf. organische Komponenten, die mit dem Aerosol mitgerissen werden. Diese anorganischen Salze und ggf. organische Komponenten schlagen sich auf den Oberflächen der Abluftkanäle nieder. Zusammen mit der ebenfalls niedergeschlagenen Feuchtigkeit können sie Anlaß für Korrosionsschäden sein, wie im folgenden näher beschrieben wird.The invention relates to a method for inhibiting corrosion of metallic surfaces which are brought into contact with moist gases. Such metallic surfaces can be found, for example, in exhaust air ducts from companies in which aqueous media are moved and / or sprayed with high turbulence and at the same time a gas, for example air, is pumped or sucked through the system. A special, but not limiting example of this is painting systems, for example in vehicle construction. In such systems, paint overspray is washed out of the exhaust air by water. The resulting exhaust air is a stream of a moist gas, which contains water at least in gaseous form, but usually also in the form of an aerosol. In addition to the water, the stream of the moist gas contains inorganic salts and possibly organic components that are carried along with the aerosol. These inorganic salts and possibly organic components are deposited on the surfaces of the exhaust air ducts. Together with the dampness which is also deposited, they can cause corrosion damage, as will be described in more detail below.
In Lackierereien wird als Material für Behälter, Rohrleitungen und Abluftkanäle zunehmend Edelstahl verwendet. Aus Kostengründen verwendet man zumeist die Sorte 1.4301. Diese ist jedoch weder korrosionsstabil gegenüber Chloridionen noch gegen Säuren. Der Grenzwert der Chloridverträglichkeit liegt bei etwa 1 000 ppm. Im Umlaufwasser der wasserberieselten Lackierkabinen selbst lassen sich die Grenzwerte für Chlorid und pH-Wert einhalten. In den Abluftkanälen gelingt dies jedoch nicht, da sich infolge der Verdunstung von Wasser wesentlich höhere Chloridwerte einstellen. Die Chloridgehalte in dem Feuchtigkeitsfilm auf den Oberflächen der Abluftkanäle können bis zu 100 000 ppm betragen. Ferner kann der pH-Wert in diesem Feuchtigkeitsfilm durch biologischen Abbau mitgerissener organischer Komponenten des Umlaufwassers in den sauren Bereich absinken. Dies führt zu Korrosionserscheinungen, in der Regel zunächst zu Spaltkorrosion und später auch zur Flächenkorrosion. Als Gegenmaßnahme kann der gesamte Kanal von Korrosionsprodukten gereinigt werden, beispielsweise durch Sandstrahlen, und anschließend beschichtet werden. Dies sind aber kostenintensive Maßnahmen, die zudem nur bei einem Stillstand der Anlage durchgeführt werden können. Zudem ist zu erwarten, daß eine Beschichtung den Vibrationen und den mitgerissenen Lösemitteln nicht lange standhält und bald durch Korrosion unterwandert wird, so daß erneut Reparaturmaßnahmen notwendig werden.In paint shops, stainless steel is increasingly being used as a material for containers, pipes and exhaust air ducts. For cost reasons, the 1.4301 grade is mostly used. However, this is neither corrosion-stable against chloride ions nor against acids. The limit value for chloride compatibility is around 1,000 ppm. The limit values for chloride and pH value can be maintained in the circulating water of the water-sprayed painting booths themselves. However, this does not succeed in the exhaust air ducts, since the evaporation of water results in significantly higher chloride values. The chloride levels in the moisture film on the surfaces of the exhaust air ducts can be up to 100,000 ppm. Furthermore, the pH value in this moisture film drops into the acidic range due to the biological degradation of entrained organic components of the circulating water. This leads to signs of corrosion, usually first of all crevice corrosion and later also surface corrosion. As a countermeasure, the entire channel can be cleaned of corrosion products, for example by sandblasting, and then coated. However, these are cost-intensive measures that can also only be carried out when the system is at a standstill. In addition, it can be expected that a coating will not withstand the vibrations and entrained solvents for long and will soon be infiltrated by corrosion, so that repair measures will be necessary again.
Um diese Korrosionsprobleme zu bekämpfen, wäre es denkbar, der Wasserphase in der Anlage, beispielsweise dem Umlaufwasser der Lackierkabinen, Korrosionsinhibitoren zuzusetzen, die zusammen mit Wassertröpfchen in den Abluftstrom mitgerissen werden. Dieses Verfahren hätte jedoch schwerwiegende Nachteile: Die Inhibitoren müßten in einer großen Menge eingesetzt werden, da sie in dem gesamten Volumen der Wasserphase in einer wirksamen Konzentration vorliegen müßten. Die Konzentration im Abluftstrom selbst ließe sich nicht weiter steuern. Weiterhin könnten die Korrosionsinhibitoren den technischen Prozeß, der in der entsprechenden Anlage abläuft, negativ beeinflussen. Im Falle von Lackierbetrieben könnten die Korrosionsinhibitoren beispielsweise die Wirksamkeit der Entklebungs- und Koaguliermittel beeinträchtigen. Außerdem würden die Korrosionsinhibitoren mit dem Lackschlamm ausgetragen und so unnütz vergeudet. Daher verbietet es sich in der Regel, der Wasserphase selbst Korrosionsinhibitoren in einer solchen Menge zuzusetzen, daß die vorstehend beschriebenen Korrosionsprobleme gelöst werden. Demgegenüber stellt sich die Erfindung die Aufgabe, ein wirksames Verfahren zum Bekämpfen der Korrosion von Metalloberflächen zur Verfügung zu stellen, die mit einem feuchten Gas in Kontakt stehen.In order to combat these corrosion problems, it would be conceivable to add corrosion inhibitors to the water phase in the system, for example the circulating water of the painting booths, which are carried along with water droplets into the exhaust air stream. However, this method would have serious disadvantages: the inhibitors would have to be used in a large amount, since they would have to be present in an effective concentration in the entire volume of the water phase. The concentration in the exhaust air stream itself could no longer be controlled. Furthermore, the corrosion inhibitors could negatively influence the technical process that takes place in the corresponding plant. In the case of paint shops, the corrosion inhibitors could impair the effectiveness of the detackifying and coagulating agents, for example. In addition, the corrosion inhibitors would be removed with the paint sludge and thus wasted. Therefore, it is generally forbidden to add corrosion inhibitors to the water phase in such an amount that the corrosion problems described above are solved. In contrast, the object of the invention is to provide an effective method for controlling the corrosion of metal surfaces which are in contact with a moist gas.
Demnach betrifft die Erfindung in ihrem allgemeinsten Aspekt ein Verfahren zur Korrosionsinhibierung metallischer Oberflächen, die mit feuchten Gasen in Kontakt gebracht werden, wobei man den feuchten Gasen Korrosionsinhibitoren in Form eines Aerosols zugibt. Bei den feuchten Gasen handelt es sich in der Regel um einen Abluftstrom, der Wasser in gasförmiger Form und/oder in Form eines Aerosols enthält. Ein solcher feuchter Abluftstrom tritt generell auf, wenn Luft durch eine Anlage gepumpt oder gesaugt wird, in der Wasser in turbulenter Bewegung gehalten und/oder versprüht wird. Beispielsweise tritt dies bei Gaswäschern auf, in denen durch versprühtes Wasser Verunreinigungen aus einem Gasstrom entfernt werden sollen. Ein weiteres Beispiel sind Abluftkanäle von Lackierbetrieben, bei denen Lackpartikel in der Abluft durch Wasser ausgewaschen werden.Accordingly, in its most general aspect, the invention relates to a method for inhibiting corrosion of metallic surfaces that come into contact with moist gases are brought, with the moist gases being added corrosion inhibitors in the form of an aerosol. The moist gases are generally an exhaust air stream which contains water in gaseous form and / or in the form of an aerosol. Such a moist exhaust air flow generally occurs when air is pumped or sucked through a system in which water is kept in turbulent motion and / or sprayed. For example, this occurs in gas scrubbers in which contaminants are to be removed from a gas stream by sprayed water. Another example are exhaust air ducts from paint shops, where paint particles in the exhaust air are washed out by water.
Die metallischen Oberflächen können beispielsweise ausgewählt sein aus Stahl, Zink, verzinktem Stahl oder Aluminium. Hierin sind auch Legierungen der genannten Metalle eingeschlossen. Bei Stahl handelt es sich insbesondere um Edelstahl, beispielsweise um den Typ 1.4301. Insbesondere ist das Verfahren geeignet zur Anwendung bei metallischen Oberflächen von Abluftkanälen in Lackierbetrieben.The metallic surfaces can be selected, for example, from steel, zinc, galvanized steel or aluminum. Alloys of the metals mentioned are also included. Steel is in particular stainless steel, for example type 1.4301. The method is particularly suitable for use on metallic surfaces of exhaust air ducts in paint shops.
Dem feuchten Gasstrom (Abluftstrom) kann man die Korrosionsinhibitoren in Form eines Aerosols kurz vor oder in dem Ablüfter selbst zusetzen. Bei der in Ablüftern vorhandenen hohen Luftgeschwindigkeit (beispielsweise 5 bis 15 m/sec.) wird das Korrosionsschutzmittel mitgerissen und gelangt genau an diejenigen Problemzonen, wo auch die Korrosion durch Aufsalzung stattfindet. Vorzugsweise fügt man dem Gasstrom die Korrosionsinhibitoren in Form einer wäßrigen Lösung oder Dispersion zu und sorgt durch geeignete Maßnahmen dafür, daß Tröpfchen dieser wäßrigen Lösung und/oder Dispersion in Form eines Aerosols in den feuchten Gasstrom mitgerissen werden. Dies kann beispielsweise dadurch erreicht werden, daß man die Lösung oder Dispersion der Korrosionsinhibitoren in den Gasstrom kontinuierlich oder diskontinuierlich einsprüht oder eindüst.The corrosion inhibitors in the form of an aerosol can be added to the moist gas stream (exhaust air stream) shortly before or in the ventilator itself. At the high air speed present in exhaust fans (e.g. 5 to 15 m / sec.), The anti-corrosion agent is entrained and reaches precisely those problem areas where corrosion by salting takes place. The corrosion inhibitors are preferably added to the gas stream in the form of an aqueous solution or dispersion and suitable measures are taken to ensure that droplets of this aqueous solution and / or dispersion in the form of an aerosol are entrained in the moist gas stream. This can be achieved, for example, by spraying or injecting the solution or dispersion of the corrosion inhibitors into the gas stream continuously or discontinuously.
Bei der Auswahl der Korrosionsinhibitoren ist zu bedenken, daß diese über den Abluftstrom in die Umwelt gelangen könnten. Daher sind ungiftige oder biologisch abbaubare Korrosionsinhibitoren bevorzugt. Beispielsweise können die Korrosionsinhibitoren ausgewählt sein aus a) polymeren Aminosäuren, insbesondere Polyasparaginsäure, oder deren Salzen, b) Carbonsäuren mit 6 bis 24, insbesondere mit 6 bis 9 C-Atomen, oder deren Salzen, c) organischen Aminen, insbesondere Alkanolaminen, oder deren Salzen, d) Metallverbindungen, insbesondere Verbindungen von Zink, Molybdän und/oder Wolfram, die beiden letztgenannten vorzugsweise in der Oxidationsstufe VI, e) anderen polymeren Carbonsäuren als Polyaminosäuren, insbesondere Polymeren oder Copolymeren von Acrylsäure, Methacrylsäure, Maleinsäure sowie teilverseiften Polyacrylamiden, oder jeweils deren Salzen, f) organischen Phosphonsäuren, insbesondere geminalen Diphosphonsäuren und Phosphonocarbonsäuren wie beispielsweise 1-Hydroxyethan-1,1- diphosphonsäure oder Phosphonobutan-1,2,4-tricarbonsäure. Weiterhin ist Octanphosphonsäure geeignet. g) Petrolsulfonaten.When selecting the corrosion inhibitors, it should be borne in mind that they could get into the environment via the exhaust air flow. Therefore, they are non-toxic or organic degradable corrosion inhibitors preferred. For example, the corrosion inhibitors can be selected from a) polymeric amino acids, in particular polyaspartic acid, or their salts, b) carboxylic acids with 6 to 24, in particular with 6 to 9 C atoms, or their salts, c) organic amines, in particular alkanolamines, or their Salts, d) metal compounds, in particular compounds of zinc, molybdenum and / or tungsten, the latter two preferably in oxidation state VI, e) polymeric carboxylic acids other than polyamino acids, in particular polymers or copolymers of acrylic acid, methacrylic acid, maleic acid and partially saponified polyacrylamides, or in each case their salts, f) organic phosphonic acids, in particular geminal diphosphonic acids and phosphonocarboxylic acids such as, for example, 1-hydroxyethane-1,1-diphosphonic acid or phosphonobutane-1,2,4-tricarboxylic acid. Octane phosphonic acid is also suitable. g) petroleum sulfonates.
Als Korrosionsinhibitoren der Gruppe b) kommen beispielsweise Carbonsäuren der Formel (I) in Betracht,Suitable corrosion inhibitors of group b) are, for example, carboxylic acids of the formula (I)
R3-COOH (I)R 3 -COOH (I)
in der R° für einen aliphatischen, linearen oder verzweigten Kohlenwasserstoffrest mit 5 bis 23 Kohlenstoffatomen und 0 bzw. 1 bis 5 Doppelbindungen oder eine R -in the R ° for an aliphatic, linear or branched hydrocarbon radical with 5 to 23 carbon atoms and 0 or 1 to 5 double bonds or an R -
44
Ph-COCH=CH-Gruppe, R^ für einen linearen oder verzweigten Alkylrest mit 8 bis 18 Kohlenstoffatomen und Ph für eine Phenylgruppe steht.Ph-COCH = CH group, R ^ is a linear or branched alkyl radical having 8 to 18 carbon atoms and Ph is a phenyl group.
Typische Beispiele sind die Fettsäuren Capronsäure, Caprylsäure, Caprinsäure, Laurinsäure, Myristinsäure, Palmitinsäure, Palmoleinsäure, Stearinsäure, Isostearinsäure, Ölsäure, Elaidinsäure, Petroselinsäure, Linolsäure, Linolensäure, Elaeostearinsäure, Arachinsäure, Gadoleinsäure, Arachidonsäure, Behensäure, Erucasäure und Clupanodonsäure sowie deren technische Gemische, wie sie beispielsweise bei der Druckspaltung von natürlichen Fetten und Ölen anfallen.Typical examples are the fatty acids caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, palmoleic acid, stearic acid, isostearic acid, oleic acid, elaidic acid, petroselinic acid, linoleic acid, linolenic acid, elaeostearic acid, arachidic acid, gadoleic acid, arachidonic acid, behenic acid Erucic acid and clupanodonic acid as well as their technical mixtures, such as those that occur in the pressure splitting of natural fats and oils.
Vorzugsweise werden Carbonsäuren der Formel (I) eingesetzt, in der R3 für Alkyl- reste mit 5 bis 17 und insbesondere mit 5 bis 8 Kohlenstoffatomen steht.Carboxylic acids of the formula (I) are preferably used in which R 3 represents alkyl radicals having 5 to 17 and in particular having 5 to 8 carbon atoms.
Beispiele für substituierte Carbonsäure sind in der Gruppe der Alkylbenzoylacrylsäuren enthalten. Ein Beispiel ist 3-(p-Examples of substituted carboxylic acids are included in the group of alkylbenzoylacrylic acids. An example is 3- (p-
Dodecylbenzoyl)acrylsäure.Dodecylbenzoyl) acrylic acid.
Als Gruppe g) von Korrosionsinhibitoren kommen anionische Tenside vom Typ der Petrolsulfonate in Betracht. Hierbei handelt es sich um Sulfoxidationsprodukte von Paraffinfraktionen mit durchschnittlich 6 bis 30, insbesondere 10 bis 20 Kohlenstoffatomen. Die Petrolsulfonate können auch als sekundäre Alkansulfonate aufgefaßt werden, wobei als Gegenionen Alkali- oder Erdalkalimetalle, Ammonium oder Alkylammonium in Betracht kommen. Vorzugsweise werden die Petrolsulfonate in Form ihrer Natrium- oder Calciumsalze eingesetzt.Anionic surfactants of the petroleum sulfonate type can be considered as group g) of corrosion inhibitors. These are sulfoxidation products of paraffin fractions with an average of 6 to 30, in particular 10 to 20, carbon atoms. The petroleum sulfonates can also be regarded as secondary alkane sulfonates, with alkali or alkaline earth metals, ammonium or alkylammonium being suitable as counterions. The petroleum sulfonates are preferably used in the form of their sodium or calcium salts.
Dabei können die Korrosionsinhibitoren der einzelnen Gruppen miteinander kombiniert werden, beispielsweise Gruppe b) mit Gruppe c) oder Gruppe d) mit Gruppe e) und/oder Gruppe f).The corrosion inhibitors of the individual groups can be combined with one another, for example group b) with group c) or group d) with group e) and / or group f).
Korrosionsinhibitoren, die Brönstedt-Säuren darstellen, setzt man vorzugsweise in Form ihrer wasserlöslichen Salze, insbesondere in Form von Alkalimetall- oder Aminsalzen ein. Hierdurch erreicht man, daß der pH-Wert der wäßrigen Lösung oder Dispersion der Korrosionsinhibitoren im besonders wirksamen Bereich von etwa 7 bis etwa 10 liegt.Corrosion inhibitors, which are Brönstedt acids, are preferably used in the form of their water-soluble salts, in particular in the form of alkali metal or amine salts. As a result, the pH of the aqueous solution or dispersion of the corrosion inhibitors is in the particularly effective range from about 7 to about 10.
Vorzugsweise setzt man dem feuchten Gas zusätzlich Spreitungsmittel als Aerosol zu. Dies kann zusammen mit der Zugabe der Korrosionsinhibitoren, jedoch auch getrennt zu diesen erfolgen. Als Spreitungsmittel sind insbesondere oberflächenaktive Substanzen wie beispielsweise Tenside geeignet. Diese Spreitungsmittel schlagen sich ebenfalls auf den metallischen Oberflächen nieder und verringern die Oberflächenspannung des Feuchtigkeitsfilms auf diesen Oberflächen. Hierdurch gelangen die Korrosionsinhibitoren leichter in Spalten und können alte Ablagerungen leichter unterwandern. Zusätzlich haben diese Spreitungsmittel einen Reinigungseffekt, so daß die regelmäßigen Reinigungsoperationen erleichtert werden.Spreading agents are preferably added to the moist gas as an aerosol. This can be done together with the addition of the corrosion inhibitors, but also separately from these. Surfactants such as surfactants are particularly suitable as spreading agents. These spreading agents are also deposited on the metallic surfaces and reduce the surface tension of the moisture film on these surfaces. As a result, the corrosion inhibitors get into gaps more easily and can easily infiltrate old deposits. In addition, these spreading agents have a cleaning effect, so that regular cleaning operations are facilitated.
Weiterhin können dem feuchten Gas zusätzlich Alkalitätsträger zugegeben werden, was vorzugsweise ebenfalls in Form eines Aerosols geschieht. Die Wirkung der Alkalitätsträger besteht neben ihrer generellen passivierenden Wirkung darin, daß die auf den metallischen Oberflächen durch biologischen Abbau mitgerissener organischer Substanzen gebildeten Säuren neutralisiert werden. Die Korrosionswirkung derartiger Säuren wird daher verringert. Die Alkalitätsträger können generell Laugen wie beispielsweise Natronlauge darstellen. Bevorzugt sind jedoch Alkalitätsträger, die ihrerseits zur Korrosionsschutzwirkung beitragen. Beispiele solcher Alkalitätsträger sind Seifen sowie organische Amine, insbesondere Alkanolamine.Alkalinity carriers can also be added to the moist gas, which preferably also takes the form of an aerosol. In addition to their general passivating effect, the effect of the alkalinity carriers is that the acids formed on the metallic surfaces by biodegradation of entrained organic substances are neutralized. The corrosion effect of such acids is therefore reduced. The alkalinity carriers can generally be alkalis such as sodium hydroxide. However, alkaline carriers are preferred, which in turn contribute to the corrosion protection effect. Examples of such alkalinity carriers are soaps and organic amines, especially alkanolamines.
Vorzugsweise setzt man die Korrosionsinhibitoren dem feuchten Gas in einer solchen Menge als Aerosol zu, daß ein m3 des feuchten Gases, beispielsweise der Abluft, 1 μg bis 10 mg, bevorzugt 10 μg bis 1 mg Korrosionsinhibitor enthält. Die wäßrige Lösung oder Dispersion der Korrosionsinhibitoren, die man als Aerosole dem feuchten Gas zugibt, enthält die Korrosionsinhibitoren vorzugsweise in einer Konzentration von 0,1 bis 20 Gew.-%, insbesondere von 1 bis 5 Gew.-%.The corrosion inhibitors are preferably added to the moist gas in an amount such as an aerosol that one m 3 of the moist gas, for example the exhaust air, contains 1 μg to 10 mg, preferably 10 μg to 1 mg, corrosion inhibitor. The aqueous solution or dispersion of the corrosion inhibitors, which are added as aerosols to the moist gas, preferably contains the corrosion inhibitors in a concentration of 0.1 to 20% by weight, in particular 1 to 5% by weight.
Durch das erfindungsgemäße Verfahren werden die eingangs geschilderten Korrosionsprobleme auf metallischen Oberflächen, die mit feuchten Gasen in Kontakt stehen, wirksam verringert. Dies verlängert die Intervalle für Pflegemaßnahmen bzw. Erneuerung der Anlagen und erhöht hierdurch deren Wirtschaftlichkeit. The method according to the invention effectively reduces the corrosion problems described at the outset on metallic surfaces which are in contact with moist gases. This extends the intervals for maintenance measures or the renewal of the systems and thereby increases their efficiency.

Claims

Patentansprüche claims
1. Verfahren zur Korrosionsinhibierung metallischer Oberflächen, die mit feuchten Gasen in Kontakt gebracht werden, wobei man den feuchten Gasen Korrosionsinhibitoren in Form eines Aerosols zugibt.1. Process for the corrosion inhibition of metallic surfaces which are brought into contact with moist gases, corrosion inhibitors being added to the moist gases in the form of an aerosol.
2. Verfahren nach Anspruch 1 , dadurch gekennzeichnet, daß die metallischen Oberflächen ausgewählt sind aus Stahl, insbesondere Edelstahl, Zink, verzinktem Stahl oder Aluminium.2. The method according to claim 1, characterized in that the metallic surfaces are selected from steel, in particular stainless steel, zinc, galvanized steel or aluminum.
3. Verfahren nach einem oder beiden der Ansprüche 1 und 2, dadurch gekennzeichnet, daß es sich bei den metallischen Oberflächen um Oberflächen von Abluftkanälen in Lackierbetrieben handelt.3. The method according to one or both of claims 1 and 2, characterized in that the metallic surfaces are surfaces of exhaust air ducts in paint shops.
4. Verfahren nach einem oder mehreren der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die Korrosionsinhibitoren in Form einer wässrigen Lösung und/oder Dispersion in das feuchte Gas eingebracht werden.4. The method according to one or more of claims 1 to 3, characterized in that the corrosion inhibitors are introduced into the moist gas in the form of an aqueous solution and / or dispersion.
5. Verfahren nach einem oder mehreren der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die Korrosionsinhibitoren ausgewählt sind aus a) polymeren Aminosäuren, insbesondere Polyasparaginsäure, oder deren Salzen, b) Carbonsäuren mit 6 bis 24, insbesondere mit 6 bis 9 C-Atomen, oder deren Salzen, c) organischen Aminen, insbesondere Alkanolaminen, oder deren Salzen, d) Metallverbindungen, insbesondere Verbindungen von Zink, Molybdän und/oder Wolfram, e) anderen polymeren Carbonsäuren als Polyaminosäuren, insbesondere Polymeren oder Copolymeren von Acrylsäure, Methacrylsäure, Maleinsäure, sowie teilverseiften Polyacrylamiden oder jeweils deren Salzen, f) organischen Phosphonsäuren, g) Petrolsulfonaten. 5. The method according to one or more of claims 1 to 4, characterized in that the corrosion inhibitors are selected from a) polymeric amino acids, especially polyaspartic acid, or their salts, b) carboxylic acids having 6 to 24, in particular having 6 to 9 carbon atoms , or their salts, c) organic amines, in particular alkanolamines, or their salts, d) metal compounds, in particular compounds of zinc, molybdenum and / or tungsten, e) polymeric carboxylic acids other than polyamino acids, in particular polymers or copolymers of acrylic acid, methacrylic acid, maleic acid , and partly saponified polyacrylamides or their salts, f) organic phosphonic acids, g) petroleum sulfonates.
6. Verfahren nach einem oder mehreren der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß man dem feuchten Gas zusätzlich Spreitungsmittel als Aerosol zugibt.6. The method according to one or more of claims 1 to 5, characterized in that additional spreading agent is added as an aerosol to the moist gas.
7. Verfahren nach einem oder mehreren der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß man dem feuchten Gas zusätzlich Alkalitätsträger zugibt.7. The method according to one or more of claims 1 to 6, characterized in that additional alkaline carriers are added to the moist gas.
8. Verfahren nach einem oder mehreren der Ansprüche 1 bis 7, dadurch gekennzeichnet, daß man dem feuchten Gas die Korrosionsinhibitoren in einer solchen Menge zugibt, daß 1 m3 des feuchten Gases 1 μg bis 10 mg Korrosionsinhibitor enthält. 8. The method according to one or more of claims 1 to 7, characterized in that the corrosion inhibitors are added to the moist gas in such an amount that 1 m 3 of the moist gas contains 1 μg to 10 mg corrosion inhibitor.
PCT/EP2001/013786 2000-12-06 2001-11-27 Corrosion inhibition using aerosols WO2002046496A2 (en)

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CN112553610A (en) * 2019-09-10 2021-03-26 天津大学 Carbon steel surface in-situ self-assembly metal-polyaspartic acid anticorrosive film and preparation method and application thereof

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US2717196A (en) * 1950-02-25 1955-09-06 Shell Dev Sheet wrapping material containing nitro-phenol compound
US2947599A (en) * 1955-07-05 1960-08-02 Little Inc A Corrosion inhibitors
DE1521900A1 (en) * 1964-10-03 1969-05-14 Nawrot Kg Hermann Corrosion protection agent and process for its production
US3749554A (en) * 1970-06-08 1973-07-31 Union Oil Co Method for reducing erosion and corrosion of metal surfaces
US3689238A (en) * 1970-10-16 1972-09-05 Universal Oil Prod Co Inhibitor injection

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112553610A (en) * 2019-09-10 2021-03-26 天津大学 Carbon steel surface in-situ self-assembly metal-polyaspartic acid anticorrosive film and preparation method and application thereof

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