DE3711611A1 - ANTI-CORROSION COMPOSITION AND THEIR USE - Google Patents

Abstract

Anti-corrosion composition containing from 60 to 98%w of a liquid hydrocarbon filling material, from 1 to 30%wt of a corrosion inhibitor and from 1 to 10%wt of a gelling agent which at least in course of time gives the composition a viscosity of at least 650cSt. at 25 DEG C, all weight percentages being based on the total of the filling material, corrosion inhibitor and gelling agent, suitable for use in pipe connectors in contact with sea water.

Description

The present invention relates to an anti-corrosion composition setting and their use in pipe connectors.

The underwater extraction of oil and gas is in the past Years of great importance. But it also has gave rise to several problems. One of those problems relies on the fact that pipelines, such as pipelines, Risers and boring bars, in constant contact with Standing sea water. However, sea water tends to form one very corrosive environment. Especially on such Places where parts of a pipeline are interconnected are (connecting elements), seems a particularly strong one Corrosion to take place. As a result of such corrosion the strength of the pipeline is greatly reduced, so that there is a risk of the line breaking. To face such a danger is an expensive one  Repair the pipeline or replace the connection element is required at relatively short intervals.

There is therefore a great need for a good anti-corrosion Composition for such pipe connectors. Usual greases have not been satisfactory for proved this purpose, regardless of whether they have a Corrosion inhibitor included or not. With usual pipe Fasteners with screw threads become the grease when assembling the individual parts of the connecting element away.

In more complicated connection systems like the one below for example in British Patents 1,573,945 and 2 064 041, it is very difficult to an anti-corrosion composition between the "male" and "female" part of the connecting element bring in.

The present invention solves those discussed above Problems.

The anti-corrosion composition according to the invention is characterized in that they contain 60 to 98 percent by weight of a Filling material in the form of a liquid hydrocarbon, 1 to 30 percent by weight of a corrosion inhibitor and 1 to Contains 10% by weight of a gelling agent which the composition has a viscosity of over time confers at least 650 mm² / s at 25 ° C, where all Percentages by weight on the total amount of filling material, Obtain corrosion inhibitor and gelling agent. The composition preferably reaches at least one Viscosity of 750 mm² / s at 25 ° C.

The anti-corrosion composition discussed above will made by filling the material in the form of a coal hydrogen, the gelling agent and the corrosion inhibitor mixed together, initially a low-viscosity Mixture is created that is easy to protect Surfaces are pumped and / or applied to them can. After a while, however, the gelling agent takes care  for increasing the viscosity of the composition. Preferential the desired viscosity becomes wise after a period of time from 60 to 600 minutes after mixing the components reached.

The liquid hydrocarbon used as filler shouldn't be corrosive itself. In addition, he should not easy with regard to safe handling be flammable. Therefore, it is preferred as the filler a hydrocarbon with an initial boiling point of at least 80 ° C used. It can be made from a variety of hydrocarbons can be selected, whereby alkanes or alkylaromatic Compounds such as alkylbenzene, alkyltoluene or alkylxylene, are particularly useful. For economic Aspects is considered a hydrocarbon filler preferably a gas oil is used, including diesel oils and heavier ones Fuel oils belong.

Within the scope of the composition according to the invention, a Variety of corrosion inhibitors can be used. Purpose moderately they have a high activity, so that they are the Resist corrosive effects of a sea water environment. Corrosion inhibitors, which salts, are preferably used of fatty acids and alkanolamines and / or alkylamines.

The gelling agent used serves to set the required viscosity. If the viscosity is too low, there is a risk that the composition will be washed away from the surface to be protected. If desired, the amount of gelling agent can be adjusted so that the composition assumes the required viscosity. Organic phosphates, in particular C _1-15 alkyl phosphates, are particularly suitable as gelling agents.

The composition according to the invention contains the individual Components in amounts corresponding to those given above Areas. Preferably the composition contains  65 to 85 percent by weight of the filler, 5 to 25 % By weight of the corrosion inhibitor and 1 to 5 % By weight of the gelling agent. If desired, can a catalyst can also be used, which the Gelling effect favorably influenced. Suitable catalysts are, for example, alkali aluminates, optionally in combination with the corresponding hydroxides. The amount of catalyst is expediently in the range from 5 to 20 Weight percent, based on the gelling agent.

The present invention also relates to the use of the specified anti-corrosion composition in a tube connecting element, which is a tubular bolt member and includes a tubular housing member, the inner surface essentially the outer surface of the bolt member corresponds, with each surface with each other in Protrusions and recesses to be brought into engagement Is provided.

The invention further relates to a method for introduction an anti-corrosion composition as described above between the bolt member and the housing member one Pipe connecting element, which is characterized in that the filler, the corrosion inhibitor and Gelling agents mixed together, this mixture under Pressure through an opening in the housing member under simultaneous Expansion of the housing member and / or pressing together pumps the bolt member and thereby a free space between the two limbs, which is created by the mixture is filled in, and that you then put the one between the two Mixture located in an increased viscosity of assumes at least 650 mm² / s at 25 ° C. The pressure on the Liquid can be used before or after the mixture has gelled lower or lift, this pressure is preferably lifted before onset of gelation.

The invention is explained in more detail below with reference to the drawings. Fig. 1 shows a partial axial section and a partial elevation of a pipe connection element, in which a bolt and a housing member are fully engaged.

Fig. 2 shows a partial axial section of a part of the pipe connecting element in a larger section.

As is apparent from FIGS. 1 and 2, comprising the pipe connection member is a tubular pin member 1 to be connected, for example by welding, to one end of a pipe 2 and a tubular housing member 3 for connection, for. B. by welding, with the end of a tube 4 , which in turn is to be connected to the tube 2 . The bolt and housing members are telescopically engageable and generally have frusto-conical outer and inner peripheral surfaces 5 and 6 , respectively, which overlap when the bolt member is fully inserted into the housing member, as shown in FIG. 1. The two links 1 and 3 have at their free outer ends radially outwardly extending surfaces 7 and 8 , and when the two links are fully telescopically connected, one of the radially outwardly extending surfaces 7 and 8 abuts one radially outwardly extending surface 9 or 10 of a shoulder which is provided at the inner end of the frustoconical surface of the housing or bolt member, whereby axially aligned forces, for example ramming forces, can be transmitted between the two members 1 and 3 , respectively. As shown in the drawing, the surface 8 of the housing member lies directly on the surface 10 of the bolt member.

The generally frustoconical peripheral surfaces 5, 6 comprise frustoconical end portions 11, 12 and 13, 14 at the inner and outer ends of the frustoconical surfaces and between these end portions the surfaces are provided with projections and recesses 15 and 16 which engage with each other let bring.

An opening 17 is provided in the housing member 3 , which leads to the area which is provided with projections and recesses, and this opening enables the introduction of a liquid under pressure.

For the assembly of the connecting element, the housing member and the bolt member are moved axially towards one another. Via the opening 17 , a liquid is supplied under pressure in order to expand the housing member and / or to compress the bolt member so that these two members can be moved further towards one another in order finally to be fully telescopically engaged with one another. This pressurized liquid, which is generally a hydraulic liquid, is then replaced by a composition according to the invention. The low-viscosity composition obtained directly after the mixing of the components is supplied under pressure through the opening 17 and thus passes between the surfaces 5 and 6 , or 8 and 10 , of the links 1 and 3 . The pressure is then released and the opening 17 is closed with a plug. After a certain period of time, the composition according to the invention assumes the required viscosity. As a result of this high viscosity, the composition does not emerge from the pipe connection element, but instead exerts a long-term anti-corrosion effect.

Example 1

For the production of stable anti-corrosion compositions according to the invention, the following starting components used:

• 1) A hydrocarbon solvent based on a  Diesel oil, which contains C₉ to C₃₀ hydrocarbons (Trade name "Corexit 8811").
• 2) A corrosion inhibitor consisting of a 73 weight percent solution of salts of a fatty acid and alkanolamines / Alkylamines in a mixture of toluene and butoxyethanol (Trade name "Corexit 8466"). The fatty acid contains two C₁₈ chain links.
• 3) A gelling agent consisting of a mixture of phosphate esters of ethanol, octanol and decanol in toluene (trade name "J 292"). (The ester mixture was obtained from Reacting 22.8% phosphoric anhydride with 15.2% ethanol, 21% octanol and 21% decanol in 20% toluene).
• 4) A catalyst in the form of sodium aluminate and sodium hydroxide (trade name "J 242").

The above components were in various amounts mixed together to form compositions Nos. 1 to 3, as indicated in Table I below. Any of these Compositions reached one after a period of time Viscosity of more than 750 mm² / s at 25 ° C and was also after still stable for nine months.

Table I

Example 2

To confirm the excellent anti-corrosive properties were metal samples in a film thickness of 50 microns with of composition No. 2 of Table I, which had a viscosity of 760 mm² / s at 25 ° C. These samples were then immersed in aerated sea water for six months. They remained completely free of signs of corrosion. While Impedance measurements were taken on the samples throughout the six months and it was thus found that the corrosion rate was less than 0.004 mm / year. Not coated with an anti-corrosion agent Metal samples, however, showed a rate of corrosion from 1 to 2 mm / year.

Claims (8)

1. Anti-corrosion composition, characterized in that it contains 60 to 98 percent by weight of a filler material in the form of a liquid hydrocarbon, 1 to 30 percent by weight of a corrosion inhibitor and 1 to 10 percent by weight of a gelling agent, which the composition has a viscosity of at least 650 over time gives mm² / s at 25 ° C, all weight percentages refer to the total amount of filler, corrosion inhibitor and gelling agent. 2. Anti-corrosion composition according to claim 1, characterized characterized as being within a period of 60 to 600 minutes after mixing the individual components Has a viscosity of at least 650 mm² / s at 25 ° C. 3. anti-corrosion composition according to claim 1 to 2, characterized in that as a filling material Hydrocarbon with an initial boiling point of at least Contains 80 ° C.   4. Anti-corrosion composition according to claim 3, characterized characterized in that they are filled with gas oil contains. 5. anti-corrosion composition according to claim 1 to 4, characterized in that it is used as a corrosion inhibitor at least one salt of a fatty acid and at least one Contains alkanolamine and / or alkylamine. 6. anti-corrosion composition according to claim 1 to 5, characterized in that it is a gelling agent contains organic phosphate. 7. Use of the anti-corrosion composition according to Claims 1 to 6 in a pipe connector, which a tubular bolt member and a tubular housing member comprises, the inner surface of which essentially corresponds to the outer surface of the bolt member, each Surface to be engaged with each other Projections and depressions. 8. Method of applying an anti-corrosion composition according to claims 1 to 6 between the bolt member and the housing member of a pipe connection element, thereby characterized in that the filling material, the corrosion inhibitor and the gelling agent mixed together, this mixture under pressure through an opening in the housing member while expanding the housing member and / or Compressing the bolt member pumps and thereby one creates free space between the two limbs, which through the mixture is filled in, and that you then the between mixture present in the two limbs an increased Viscosity of at least 650 mm² / s at 25 ° C can be assumed.