Cloud-free stabilization of dispersions of water in hydrocarbon fractions boiling in the diesel or heating oil range.

The invention relates to new possibilities of emulsifying and stabilizing limited amounts of water in hydrocarbon fractions of daily use, in particular in such fractions of the diesel or heating oil sector.

As is known, technical hydrocarbon fractions of the type mentioned contain limited amounts of water, which can be, for example, in the range from 0.5 to 10% by weight. This is usually caused by the fact that small amounts of water are still present in lines or storage tanks as a result of flushing and cleaning operations, or that they form as condensation water in the storage tanks as a result of the atmospheric humidity. Since water in diesel or Heating oil is only soluble with less than 0.5% by weight, separate phases occur with larger amounts of water. In practice, this results in undesirable side effects such as corrosion of the storage tanks when storing water-containing diesel and heating oil.

The invention is based on the object of being able to reliably emulsify and stabilize limited amounts of water of the order in question in hydrocarbon fractions of the type mentioned, such that opaque, clear, single-phase liquids are present even when the material is at temperatures below freezing, for example at temperatures up to -5 to -10 ° C is cooled.

The technical solution of the invention lies in the use of certain selected surfactant mixtures as emulsifiers and / or stabilizers for the water contents of the hydrocarbon fractions of the diesel or heating oil range described here.

The invention accordingly relates to the use of a multicomponent surfactant mixture of at least 2 components of the surfactant class A listed below, if desired in a mixture with surfactants of the surfactant classes B and / or C listed below, wherein the multicomponent surfactant mixture has a turbidity temperature of 35 to 70 ° C - determined according to DIN 53917 - for turbidity-free emulsification and stabilization of water in hydrocarbon fractions of the type mentioned, where the following applies: Surfactant class A: ethoxylates of octylphenol, nonylphenol and / or isotridecyl alcohol, each with 1 to 7 EO (ethylene oxide units), Surfactant class B: coconut alcohol ethoxylates with 1 to 7 EO, Surfactant class C: oleyl alcohol ethoxylates with 1 to 7 EO.

It has been shown that this choice of the particular surfactant classes A, B and C in connection with the determination of the hydrophilicity of the surfactant mixture used - determined at the clouding temperature according to DIN 53917 - achieves the object of the invention.

The invention provides for the use of a mixture of at least 2 class A surfactants. The use of surfactants from classes D and / or C may be desirable, but is not necessary. The appropriate selection of the respective mixture components is possible within the scope of the specified substance classes by simply examining the cloud point of the surfactant mixture to be used in accordance with DIN 53917. As is known, the turbidity temperature of a solution of 5 g of the surfactant or surfactant mixture in 25 g of an aqueous 25% butyl diglycol solution is determined here. According to the invention, the turbidity temperature of the surfactant mixtures from classes A and, if desired, B and / or C used for emulsification or stabilization should preferably be in the range from 40 to 60 ° C. and in particular in the range from 45 to 55 ° C.

By selecting and combining the surfactant components specified according to the invention, the safe emulsification or Stabilization of the water content present in the hydrocarbon mixture - which can usually be up to about 5% by weight - with the use of 0.5 to 10% by weight of the surfactant mixture to give clear, stable solutions even when the hydrous hydrocarbon fractions are only at temperatures below be cooled to room temperature and even below 0 ° C. The water content of the hydrocarbon fractions affected here is frequently not more than about 3% by weight. Clear solutions can then be prepared here using up to about 5% by weight, in particular about 1 to 5% by weight, of the surfactant mixtures according to the invention, in each case based on 100 parts by weight of diesel or heating oil fraction ° C and even below it have unchanged single-phase properties. The described susceptibility to faults in the practical handling of the hydrocarbon fractions affected here are thus reliably eliminated for the practical needs of everyday life.

As indicated, from surfactant class A, at least 2 surfactants are used in a mixture with one another. It can be particularly suitable here to mix ethoxylates of the type mentioned with 3 EO in combination with ethoxylates of the type mentioned with 5 EO. Nonylphenol ethoxylates of the type mentioned can be of particular importance.

Preferred surfactant mixtures for the use according to the invention are within the following ranges: 20 to 60% by weight of nonylphenol-3 EO 20 to 80% by weight of nonylphenol-5 EO 0 to 30 wt .-% oleyl and / or coconut alcohol-5 EO

In the preferred embodiment, the surfactant component B is based on a coconut alcohol of the following C chain distribution: C₁₂- 55% by weight, C₁₄- 25% by weight, C₁₆- 10% by weight and C₁₈- 10% by weight.

The oleyl alcohol base for the surfactant component C can have iodine numbers in the range from 40 to 170.

The surfactant components used according to the invention for water stabilization are inexpensive commercial products. In the intended use of the appropriately loaded hydrocarbon fractions - especially when these hydrocarbon fractions are burned for energy generation - these components do not interfere.

example

Using various surfactant mixtures according to the invention, the nature of diesel / water mixtures is assessed. The following table shows the composition of the surfactant mixture, the cloud temperature (DIN 53917) of the surfactant mixture and the assessment of the emulsion properties at 20 ° C for the following basic formulation: Diesel-hydrocarbon mixture 95% by weight surfactant mixture according to the invention 4% by weight Water 1% by weight<tables id="tabl0001" num="0001"><img file="EP0242832A2_D0001.tif" /></tables>