WO2012117004A2

WO2012117004A2 - Medium chain alkanols in additive concentrates for improving the reduction of foam in fuel oils

Info

Publication number: WO2012117004A2
Application number: PCT/EP2012/053392
Authority: WO
Inventors: Harald BÖHNKE
Original assignee: Basf Se
Priority date: 2011-03-01
Filing date: 2012-02-29
Publication date: 2012-09-07
Also published as: WO2012117004A3

Abstract

The invention relates to C₅- to C₁₅-alkanols which can be used to improve the defoaming effect of a silicon-containing anti-foaming agents in fuel oils, in particular in bio-fuel oils, which contain at least one additive having a detergent effect. Said type of alkanols are used in additive concentrates which contain, in addition to aromatic hydrocarbon or hydrocarbon mixtures having a boiling point of between 100 - 250°C or C₅- to C₁₂-alkyl nitrates and silicon-containing anti-foaming agents, additives having a detergent effect and optionally commercially available dehazers.

Description

Medium-chain alkanols in additive concentrates to improve the foam reduction in fuel oils

description

The present invention relates to the use of medium-chain alkanols for improving the defoaming action of a silicon-containing antifoam in fuel oils containing at least one detergent-effect additive. Furthermore, the present invention relates to an additive concentrate and its use for improving the foam reduction in fuel oils containing medium-chain alkanols, aromatic hydrocarbons or hydrocarbon mixtures and / or alkyl nitrates, silicon-containing antifoams and detergent-effect additives. The subject of the present application is also a corresponding additive fuel oil. Fuel oils usually contain antifoaming agents which are intended to prevent foaming of the fuel oil during movement or mechanical stress, for example when decanting or filling into storage tanks or tanks, or to reduce it to a tolerable degree. Foaming, reduced filling volumes, longer filling times and thus lower efficiency of filling stations are the main reasons why antifoam agents (also called defoamers) are today standard components in modern multifunctional diesel additive packages. Usually, silicon-containing antifoam agents based on organosilicon chemistry, such as polysiloxanes or silicone oils, are customary in this case.

For example, WO 00/39254 (1) describes additive packages which can be used in fuel oils and which, as additive with detergent action, the reaction product of polyisobutenylsuccinane nanohydride (with a polyisobutenyl chain with M _n = 950) with tetraethylenepentamine, as cetane number improver 2-ethylhexylnitrate and as a solvent 2-ethylhexanol in combination with a commercially available organosilicone antifoam agent. The weight ratio of 2-ethylhexyl nitrate to 2-ethylhexanol never exceeds 3: 1.

From US 2010/0107479 A1 (2) a diesel fuel additive package is known, which according to Table 1 there as an additive with detergent effect 42 mg / kg of the reaction product of polyisobutenylsuccinanhydrid with tetraethylenepentamine in the molar ratio 1: 1, 20 mg / kg 2-ethylhexyl nitrate as a solvent, 132 mg / kg of an aromatic hydrocarbon mixture as a further solvent and 8 mg / kg of a conventional siloxane antifoam agent.

EP 0 681 023 A1 (3) describes fuel oils such as diesel fuels, kerosene, turbine fuels, heating oils and, inter alia, biofuel oils which comprise vegetable oils, which contain metal-containing detergents such as alkali or alkaline earth metal salts of acids or phenols, antifoams such as water-soluble polyethers Polysiloxane copolymers and ashless dispersants such as polyisobutenyl succinimides and, optionally, other components such as solvents, for example aromatic hydrocarbons, oil-soluble alcohols. demulsifiers, corrosion inhibitors, carrier liquids, antioxidants, metal deactivators, cold flow improvers or wax inhibitors.

However, the effect of antifoams in fuel oils is still in need of improvement, in particular when mixed with the fuel oils or diesel fuels in multifunctional diesel additive packages containing as main active components ashless additives with detergent action. The object underlying the present invention was to improve the defoaming action of the known antifoams, in particular the silicon-containing antifoams, and to provide a corresponding additive concentrate for use as an additive package in fuel oils, which improves the foam reduction in fuel oils.

Accordingly, in a first aspect of the present invention, the use of a C5 to C15 alkanol for improving the defoaming action of a siliceous antifoam agent in fuel oils containing at least one detergent-effect additive has been found.

Furthermore, in a second aspect of the present invention, an additive concentrate was found which

(A) 0.1 to 10% by weight, in particular 1 to 8% by weight, especially 3 to 6% by weight, of at least one C5 to Cis alkanol,

(B) 0.5 to 80% by weight, in particular 5 to 75% by weight, especially 15 to 70% by weight,

either (i) at least one aromatic hydrocarbon or hydrocarbon mixture having a boiling point or a predominant boiling range in the temperature range from 100 ° C to 250 ° C or (ii) at least one

C5 to C12 alkyl nitrates or (iii) a mixture of (i) and (ii), with the proviso that the amount of component (B) is at least five times that amount

of the C5 to Cis alkanol of component (A),

(C) 0.01 to 2 wt .-%, in particular 0.1 to 1, 5 wt .-%, especially 0.4 to 1, 3 wt .-%, of at least one silicon-containing antifoam agent, (D) 1 to 30 wt .-%, in particular 7 to 29 wt .-%, especially 15 to 28 wt .-%,

at least one additive with detergent effect and

(E) 0 to 5% by weight, in particular 0.1 to 5% by weight, especially 1 to 3.5% by weight,

at least one commercial dehazer, wherein the sum of components (A) to (E) in each case is 100 wt .-%, and provided that in addition at least one of the following criteria is met: (γ) the amount of the detergent-additive additive of component (D) is at least 10 times, more preferably at least 15 times, the amount of the silicon-containing antifoam agent of component (C);

(δ) the amount of C5 to Cis alkanol of component (A) is at least that

Threefold, in particular at least four times, the amount of the silicon-containing antifoam agent of component (C) Preferably, both criteria (.gamma.) And (.delta.) Are met.

The improved effect of the present invention is due to the use of certain medium-cetane alkanols and above all the exactly matched ratio of the components (A), (B), (C) and (D). The use according to the invention of said medium-chain alkanols has an advantageous effect on the foaming behavior, especially in fuel oils which contain or consist of biofuel oils.

Medium-chain alkanols which are component (A) in the additive concentrate according to the invention are C5- to cis-alkanols, in particular CQ- to C3-alkanols, especially C10-C10-alkanols, which are linear or preferably branched. In a preferred embodiment, n-octanol, 2-ethylhexanol, n-nonanol, 2-propylheptanol, n-decanol, n-undecanol, n-dodecanol, n-tridecanol or isotridecanol are used in both aspects of the present invention. It is also possible to use a mixture of said alkanols. Very particular preference is given to 2-ethylhexanol.

Silica-containing antifoams of component (C) are to be understood as meaning all known antifoams of organic structure which are customary in the mineral oil sector and which contain one or more silicon atoms incorporated in the molecule. These may be, for example, polysiloxanes or silicone oils. In a preferred embodiment, polyether-modified polysiloxanes are used in both aspects of the present invention. These may, for example, have the structure of a polyether-polysiloxane copolymer.

For the purposes of the present invention, additives having a detergent action of component (D) are compounds whose action in an internal combustion engine, in particular a diesel engine, consists predominantly or at least essentially in eliminating and / or increasing deposits prevent. The detergents are preferably amphiphilic substances which have at least one hydrophobic hydrocarbon radical having a number-average molecular weight (M _n ) of from 85 to 20,000, in particular from 300 to 5,000, in particular from 500 to 2,500, and at least one polar group , Preferably, the detergent-effect additives are selected hereunder:

(i) Compounds derived from succinic anhydride with

Hydroxy and / or amino and / or amido and / or imido groups; acid-free quaternized nitrogen compounds obtainable by addition of a

A compound containing at least one reactive with an anhydride oxygen or

Nitrogen-containing group and additionally contains at least one quaternizable amino group, to a polycarboxylic anhydride compound and subsequent

quaternization;

(iii) polytetrahydrobenzoxazines and bistetrahydrobenzoxazines

Succinic anhydride derived groupings containing hydroxyl and / or amino and / or amido and / or imido groups according to group (i) above are preferably corresponding derivatives of polyisobutenyl succinic anhydride prepared by reacting conventional or highly reactive polyisobutene with M _n = 300 to 5000, especially with M _n = 500 to 2500, are obtainable with maleic anhydride by thermal means or via the chlorinated polyisobutene. Of particular interest here are derivatives with aliphatic polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine or tetraethylenepentamine. The groups having hydroxyl and / or amino and / or amido and / or imido groups are, for example, carboxylic acid groups, acid amides, acid amides of di- or polyamines which, in addition to the amide function, still have free amine groups, succinic acid derivatives with an acid group. and an amide function, carboximides with monoamines, carbonic acid imides with di- or polyamines which, in addition to the imide function, still have free amine groups, and diimides which are formed by the reaction of di- or polyamines with two succinic acid derivatives. Such fuel additives are described in particular in US Pat. No. 4,849,572. Acid-free quaternized nitrogen compounds according to the above group (ii) obtained by addition of a compound containing at least one anhydride-reactive oxygen or nitrogen-containing group and additionally at least one quaternizable amino group to a polycarboxylic anhydride compound and subsequent quaternization, in particular with a Epoxy in the absence of free acid, are described in EP patent application Az. 10 168 622.8. Suitable compounds having at least one anhydride-reactive oxygen or nitrogen-containing group and additionally at least one quaternizable amino group are in particular polyamines having at least one primary or secondary amino group and at least one tertiary amino group. Particularly suitable polycarboxylic acid anhydrides are dicarboxylic acids such as succinic acid having a longer-chain hydrocarbyl substituent, preferably having a number-average molecular weight M _n for the hydrocarbyl substituent of from 200 to 10,000, especially from 350 to 5,000. Such a quaternized nitrogen compound is For example, the obtained at 40 ° C reaction product of polyisobutenylsuccinic anhydride in which the polyisobutenyl typically has a M _n of 1000, with 3- (dimethyl-amino) - propylamine, which is a polyisobutenylsuccinic and then with styrene oxide in the absence of free acid at 70 ° C is quaternized.

Polytetrahydrobenzoxazines and bistetrahydrobenzoxazines according to group (iii) above are described in EP patent application Az. 10 194 307.4. Such Polytetrahydrobenzoxazi- ne and Bistetrahydrobenzoxazine are obtainable by successive in a first reaction step a d- to C2o-alkylenediamine with two primary amino functions, for example 1, 2-ethylenediamine, with a d- to Ci2-aldehyde, eg formaldehyde, and a d- to Ce-alkanol at a temperature of 20 to 80 ° C with elimination and removal of water, wherein both the aldehyde and the alcohol in each case in more than twice the molar amount, in each case in the 4-fold molar amount, are used opposite the diamine, in a second reaction step, the condensation product thus obtained with a phenol having at least one long-chain substituent having 6 to 3000 carbon atoms, for example a tert-octyl, n-nonyl, n-dodecyl or Polyisobutylrest with a M _n of 1000 bears, in stoichiometric ratio to the originally used alkylenediamine of 1, 2: 1 to 3: 1 at a temperature of 30 to 120 ° C. and if appropriate, in a third reaction step, the resulting bistetrahydrobenzoxazine is heated to a temperature of 125 to 280 ° C for at least 10 minutes.

Particularly preferred as the at least one detergent-effect additive in both aspects of the present invention are compounds having succinic anhydride-derived moieties having hydroxy and / or amino and / or amido and / or imido groups, but especially a compound from the group (i) which is a polyisobutenyl-substituted succinimide.

In the context of the present invention, fuel oils are to be understood as meaning in particular middle distillate fuels, especially diesel fuels. But also an application of the present invention in fuel oil or kerosene is possible. Diesel fuels or middle distillate fuels are usually petroleum raffinates, which generally have a boiling range of 100 to 400. These are mostly distillates with a 95% point up to 360 ° C or even beyond. However, these may also be so-called "ultra low sulfur diesel" or "city diesel", characterized by a 95% point of, for example, a maximum of 345 ° C and a maximum sulfur content of 0.005 wt .-% or by a 95% point of example 285 ° C and a maximum sulfur content of 0.001 wt .-%. In addition to refining diesel fuels whose major components are longer chain paraffins, those obtainable by coal gasification or gas liquefaction [GTL] fuels are also suitable. Also suitable are mixtures of the abovementioned diesel fuels with regenerative fuels (biofuel oils) such as biodiesel or bioethanol. Of particular interest currently are low sulfur diesel fuels, that is having a sulfur content of less than 0.05% by weight, preferably less than 0.02% by weight, more preferably less than 0.005% by weight, and especially of fewer than 0.02% by weight, in particular less than 0.005% by weight and especially less than 0.001% by weight of sulfur. Diesel fuels can also contain water, for example in an amount of up to 20% by weight, for example in the form of diesel-water microemulsions or as so-called "white diesel".

In a preferred embodiment, the C5- to cis-alkanols or the inventive additive concentrate according to the present invention are used in fuel oils which are (a) from 0.1 to 100% by weight, preferably from 0.1 to less than 100 Wt .-%, in particular to 10 to 95 wt .-%, especially to 30 to 90 wt .-%, of at least

a biofuel based on fatty acid esters, and at 0 to 99.9 wt .-%, preferably to more than 0 to 99.9 wt .-%, in particular to 5 to 90 wt .-%, especially to 10 to 70 Wt .-%, of middle distillates of fossil origin and / or of vegetable and / or animal origin, which are substantially hydrocarbon mixtures and are free of fatty acid esters exist.

Of course, the fuel oils may also consist of at least 100% by weight of at least one biofuel (a) based on fatty acid esters. The fuel oil component (a) is usually referred to as "biodiesel". These are preferably substantially alkyl esters of fatty acids derived from vegetable and / or animal oils and / or fats. Alkyl esters are usually lower alkyl esters, especially C 4 to C 4 alkyl esters, understood by transesterification of occurring in vegetable and / or animal oils and / or fats glycerides, especially triglycerides, by means of lower alcohols, such as ethanol, n-propanol, iso-propanol, n-

Butanol, iso-butanol, sec-butanol, tert-butanol or especially methanol ("FAME") are available.

Examples of vegetable oils which are converted into corresponding alkyl esters and thus can serve as a basis for biodiesel are castor oil, olive oil, peanut oil, palm kernel oil, coconut oil, mustard oil, cottonseed oil, and in particular sunflower oil, palm oil, soybean oil and rapeseed oil. Other examples include oils that can be extracted from wheat, jute, sesame and the shea nut; furthermore, arachis oil, jatropha oil and linseed oil are also usable. The recovery of these oils and their conversion to the alkyl esters are known in the art or may be derived therefrom. It is also possible to convert already used vegetable oils, for example used frying oil, if appropriate after appropriate purification, into alkyl esters and thus serve as the basis for biodiesel. Vegetable fats are also useful in principle as a source of biodiesel, but play a minor role.

Examples of animal fats and oils that are converted into corresponding alkyl esters and thus can serve as the basis for biodiesel are fish oil, beef tallow, pig tallow and similar fats and oils that are produced as waste in the slaughtering or recycling of farm animals or wild animals.

As the said vegetable and / or animal oils and / or fats underlying saturated or unsaturated fatty acids, which usually have 12 to 22 carbon atoms and may carry additional functional group such as hydroxyl groups, occur in the alkyl esters in particular lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, Linoleic acid, linolenic acid, elaidic acid, erucic acid and / or ricinoleic acid.

Typical lower alkyl esters based on vegetable and / or animal oils and / or fats which are used as biodiesel or biodiesel components are, for example, sunflower methyl ester, palm oil methyl ester ("PME"), soybean oil methyl ester ("SME") and in particular rapeseed oil methyl ester (" RME ").

However, it is also possible to use the monoglycerides, diglycerides and especially triglycerides themselves, for example castor oil, or mixtures of such glycerides as biodiesel or components for biodiesel.

In the context of the present invention, the fuel oil component (b) should be understood to mean the abovementioned middle distillate fuels, especially diesel fuels, in particular those which boil in the range from 120 to 450.degree.

In a preferred embodiment, the C5 to Cis alkanols or additive concentrate according to the present invention are used to improve the defoamer action of the silicon-containing antifoam agent in fuel oils such that the improvement is to the extent that at least one of the following criteria is met :

(a) Reduction of the foam volume compared to the defoamer effect of

of the same silicon-containing antifoam agent in the same fuel oil in the absence of a C5 to Cis alkanol at least 10%, in particular to

at least 14%, determined in accordance with the BNPe NF-M 07-075 foam test; (ß) reducing the foam disintegration time from the defoamer effect of the same silicon-containing antifoam agent in the same fuel oil in the absence of a C5 to Cis alkanol by at least 20%, in particular

at least 35%, determined according to the BNPe NF-M 07-075 foam test

Preferably both criteria (a) and (ß) are fulfilled.

The BNPe NF-M 07-075 foam test is a common measurement method for determining the foam volume and foam decay time of fuel oil samples. For this purpose, a measuring apparatus standardized according to this standard is used.

The additive concentrate according to the invention contains as component (B) in the function of a substantially non-polar solvent, which in interaction with the component (A) as the polar solvent the desired defoaming action, as a first alternative (i) one or more aromatic hydrocarbons, e.g. Toluene, xylenes or homologous mono- or dialkylbenzenes as well as from aromatic hydrocarbons existing or aromatic hydrocarbons as main components containing technical solvent mixtures of the names Shellsol® (manufacturer: Royal Dutch / Shell Group), Exxol® or Solvesso® (manufacturer: ExxonMobil) or solvent Naphtha.

As a second alternative (ii) for the component (B) are C5 to Ci2-Alkylnitrate into consideration, which are to function in the fuel oil as Cetanzahlverbesserer or ignition accelerator. Such alkyl nitrates are in particular nitrate esters of unsubstituted or substituted aliphatic or cycloaliphatic alcohols, usually having 5 to 10 carbon atoms. The alkyl group in these nitrate esters may be linear or branched, saturated or unsaturated. Typical examples of such nitrate esters are n-amyl nitrate, isoamyl nitrate, 2-amyl nitrate, 3-amyl nitrate, tert-amyl nitrate, n-hexyl nitrate, n-heptyl nitrate, sec-heptyl nitrate, n-octyl nitrate, 2-ethylhexyl nitrate, sec-octyl nitrate, n-nonyl nitrate, n-decyl nitrate, cyclopentyl nitrate, cyclohexyl nitrate, methylcyclohexyl nitrate and isopropylcyclohexyl nitrate and branched decyl nitrates having an n-propyl or isopropyl radical in the 2-position of the alkyl chain, as described in WO 2008/092809 are. Furthermore, nitrate esters of alkoxy-substituted aliphatic alcohols such as 2-ethoxyethyl nitrate, 2- (2-ethoxyethoxy) ethyl nitrate, 1-methoxypropyl nitrate or 4-ethoxybutyl nitrate are also suitable, for example. Also suitable are diol nitrates such as 1,6-hexamethylene dinitrate. Of the alkylnitrates mentioned, 2-ethylhexyl nitrate is the most common cetane number improver and is also preferred for the present invention.

As a third alternative (iii) for component (B), mixtures of (i) and (iii) are also suitable, for example mixtures of 1 to 99 parts by weight of (i) and 99 to 1 part by weight of (ii) , in particular from 10 to 90 parts by weight of (i) and 90 to 10 parts by weight of (ii), especially of 25 to 75 parts by weight of (i) and 75 to 25 parts by weight of (ii), wherein the aromatic hydrocarbon (i) and the alkyl nitrates (ii) together account for the said amounts in the additive concentrate according to the invention. Suitable co-additives of component (E) are suitable dehazers, for example alkoxylated phenol-formaldehyde condensates. The additive concentrate according to the invention is usually added to the fuel oil in such an amount that the detergent-effect additive of component (D) or a mixture of several such detergent-effecting additives in the fuel oil in an amount of from 10 to 2000% by weight. ppm, in particular from 20 to 1000 ppm by weight, especially from 30 to 500 ppm by weight, is present.

The additive concentrate according to the invention or the fuel oil additized therewith, ie corresponding diesel fuels or middle distillate fuels or the mentioned mixtures of biofuel oils and middle distillates of fossil, vegetable or animal origin, can furthermore contain other customary co-additives, in particular cold flow improvers, corrosion inhibitors, demulsifiers, antioxidants and stabilizers, metal deactivators , Antistatic agents, lubricity improvers, dyes (markers) and / or other diluents and solvents.

As further co-additives suitable cold flow improvers are, for example, copolymers of ethylene with at least one further unsaturated monomer, especially ethylene-vinyl acetate copolymers.

Corrosion inhibitors suitable as further co-additives are, for example, succinic esters, especially with polyols, fatty acid derivatives, e.g. Olsäureester, oligomerized fatty acids and substituted ethanolamines.

Demulsifiers suitable as further co-additives are, for example, the alkali and alkaline earth metal salts of alkyl-substituted phenol and naphthalenesulfonates and the alkali and alkaline earth metal salts of fatty acid, furthermore alcohol alkoxylates, e.g. Alcohol ethoxylates, phenol alkoxylates, e.g. tertiary butyl phenol ethoxylates or tertiary pentyl phenol ethoxylates, fatty acid, alkyl phenols, condensation products of ethylene oxide and propylene oxide, e.g. Ethylene oxide-propylene oxide block copolymers, polyethyleneimines and polysiloxanes.

As further co-additives suitable antioxidants are, for example, substituted phenols, e.g. 2,6-di-tert-butylphenol and 2,6-di-tert-butyl-3-methylphenol, as well as phenylenediamines, e.g. N, N'-di-sec-butyl-p-phenylenediamine.

Metal deactivators useful as further co-additives include, for example, salicylic acid derivatives, e.g. N, N'-disalicylidene-1,2-propanediamine.

A lubricity improver suitable as a further coadditive is, for example, glycerol monooleate. If the said co-additives and / or further diluents or solvents are used, they are used in the quantities customary for this purpose. The subject of the present invention is also an additive fuel oil which contains a larger amount of basic fuel oil

(a) from 0.1 to 100% by weight of at least one biofuel based on fatty acid esters, and

(b) from 0 to 99.9% by weight of middle distillates of fossil origin and / or of

vegetable and / or animal origin, which are substantially hydrocarbon mixtures and are free of fatty acid esters, consists, and contains a smaller amount of the additive concentrate according to the invention.

The following examples are intended to illustrate the present invention without limiting it. Examples

In a diesel fuel ("DK 1") compliant with the EN 590 standard and containing 7% by weight of biodiesel (FAME), the foaming behavior was determined in accordance with BNPe NF-M 07-075- Foam test determines:

An additive formulation ("AF A", for comparison) of the composition 25 wt .-% of a commercially available polyisobutenyl-substituted succinimide (Kerocom® PIBSI Fa. BASF SE) as an additive with detergent effect, 72 wt .-% Solvesso® 150 as aromatic hydrocarbon mixture, 1 wt .-% of a commercially available silicon-containing antifoaming agent and 2 wt .-% of a commercial Dehazers was added in a dosage of 200 mg / kg of the above-identified fuel DK 1. The foam volume and foam decay time of AFA additized fuel were determined.

Another additive formulation ("AF B", according to the present invention) of the composition 25 wt .-% of a commercial polyisobutenyl-substituted succinimide (Kerocom® PIBSI Fa. BASF SE) as an additive with detergent effect, 67 wt. % Solvesso® 150 as an aromatic hydrocarbon mixture, 5% by weight of 2-ethylhexanol, 1% by weight of a commercially available silicon-containing antifoam and 2% by weight of a commercial dehazer was added to the above-identified fuel at a dosage of 200 mg / kg DK 1 added. The foam volume and foam decay time of AFA additized fuel were determined. The following table shows the results of the determinations: Fuel Foam volume Foam disintegration time of unadditized DK 1 95 ml 35 sec

AF A (for comparison) 35 ml 10 sec

AF B (according to the invention) 30 ml 6 sec

Claims

claims

Use of a C5 to Cis alkanol for improving the defoaming action of a silicon-containing antifoam agent in fuel oils, which contain at least one additive with a detergent effect.

Use according to claim 1 in fuel oils which

(a) from 0.1 to less than 100% by weight of at least one biofuel oil,

based on fatty acid esters, and

(b) to greater than 0 to 99.9 weight percent of middle distillates of fossil origin

and / or of vegetable and / or animal origin, which are substantially hydrocarbon mixtures and are free of fatty acid esters.

Use according to claims 1 or 2, characterized in that the improvement of the defoamer action of the silicon-containing antifoam agent is carried out to the extent that at least one of the following criteria is fulfilled:

(a) Reduction of the foam volume compared to the defoamer effect

the same silicon-containing antifoam agent in the same fuel oil in the absence of a C5 to Cis alkanol of at least 10% as determined by the BNPe NF-M 07-075 foam test;

(β) Reduction of the foam disintegration time compared to the defoamer action

of the same siliceous antifoam agent in the same fuel oil in the absence of a C5 to Cis alkanol by at least 20% as determined by the BNPe NF-M 07-075 foam test

Use according to claims 1 to 3, wherein the C5 to Cis alkanol is n-octanol, 2-ethylhexanol, n-nonanol, 2-propylheptanol, n-decanol, n-undecanol, n-do-decanol, n- Tridecanol or isotridecanol.

Use according to claims 1 to 4, wherein the silicon-containing antifoam agent is a polyether-modified polysiloxane.

Use according to claims 1 to 5, wherein the detergent-effect additive comprises compounds having succinic anhydride-derived moieties with hydroxy groups. and / or amino and / or amido and / or imido groups.

7. Additive concentrate containing

(A) 0.1 to 10% by weight of at least one C5 to Cis alkanol,

(B) 0.5 to 80% by weight of either (i) at least one aromatic hydrocarbon or hydrocarbon mixture having a boiling point or a predominant boiling range in the temperature range from 100 ° C. to 250 ° C. or (ii) at least one C5- to C12- Alkyl nitrates or (iii) one

Mixture of (i) and (ii), with the proviso that the amount of component (B) is at least five times the amount of the C5 to Cis alkanol of component (A),

(C) 0.01 to 2% by weight of at least one silicon-containing antifoam agent,

(D) 1 to 30 wt .-% of at least one additive with detergent effect and

(E) 0 to 5 wt .-% of at least one commercially available Dehazers, wherein the sum of components (A) to (E) in each case is 100 wt .-%, and with the proviso that additionally meets at least one of the following criteria becomes:

(γ) is the amount of the detergent additive of component (D)

at least ten times the amount of the silicon-containing antifoam agent of component (C);

(δ) the amount of the C5 to Cis alkanol of component (A) is at least three times the amount of the silicon containing antifoam agent of component (C)

8. Additive concentrate according to claim 7, wherein the C5 to Cis-alkanol n-octanol, 2-ethylhexanol, n-nonanol, 2-propylheptanol, n-decanol, n-undecanol, n-dodecanol, n-tridecanol or isotridecanol is.

The additive concentrate of claim 7 or 8, wherein the silicon-containing antifoam agent is a polyether-modified polysiloxane.

10. The additive concentrate according to claims 7 to 9, wherein the detergent-additive is a compound having succinic anhydride-derived moieties having hydroxy and / or amino and / or amido and / or imido groups.

1 1. Use of the additive concentrate according to claims 7 to 10 for improving the foam reduction in fuel oils.

12. Additiviertes fuel oil, containing a larger amount of basic fuel oil, which

(b) from 0 to 99.9% by weight of middle distillates of fossil origin and / or

of vegetable and / or animal origin, which are substantially hydrocarbon mixtures and are free of fatty acid esters, and a minor amount of the additive concentrate of claims 7 to 10.