Compositions, Uses and Methods for Improving The Low Temperature Properties of a Middle Distillate Fuel

Abstract

A method of improving the low temperature properties of a middle distillate fuel composition comprising: (a) a nitrogen-containing dispersant; and (b) one or more low temperature property enhancers which are not fumarate vinyl ester copolymers and which are selected from (x) wax antisettling additives; (y) middle distillate flow improvers and mixtures thereof; the method comprising adding to the fuel an additive (c) which is a copolymer comprising units of formula (A): and units of formula (B): wherein R is an alkyl group and each of R.sup.1 and R.sup.2 is an alkyl group.

##STR00001##

Claims

1. A method of improving the low temperature properties of a middle distillate fuel composition comprising: (a) a nitrogen-containing dispersant; and (b) one or more low temperature property enhancers which are not fumarate vinyl ester copolymers and which are selected from (x) wax antisettling additives; (y) middle distillate flow improvers and mixtures thereof; the method comprising adding to the fuel an additive (c) which is a copolymer comprising units of formula (A): ##STR00020## and units of formula (B): ##STR00021## wherein R is an alkyl group and each of R.sup.1 and R.sup.2 is an alkyl group.

2. (canceled)

3. An additive composition for improving the low temperature properties of a middle distillate fuel composition the additive composition comprising: (a) a nitrogen-containing dispersant; (b) one or more low temperature property enhancers which are not fumarate vinyl ester copolymers and which are selected from (x) wax antisettling additives (y) middle distillate flow improvers and mixtures thereof; and (c) a copolymer comprising units of formula (A): ##STR00022## and units of formula (B): ##STR00023## wherein R is an alkyl group and each of R.sup.1 and R.sup.2 is an alkyl group.

4. A middle distillate fuel composition comprising: (a) a nitrogen-containing dispersant; (b) one or more low temperature property enhancers which are not fumarate vinyl ester copolymers and which are selected from (x) wax antisettling additives; (y) middle distillate flow improvers and mixtures thereof; and (c) a copolymer comprising units of formula (A): ##STR00024## and units of formula (B): ##STR00025## wherein R is an alkyl group and each of R.sup.1 and R.sup.2 is an alkyl group.

5. The method according to claim 1 wherein additive (c) is prepared by copolymerising vinyl ester monomers and dialkyl fumarate monomers.

6. The method according to claim 1 wherein R is methyl.

7. The method according to claim 1 wherein each of R.sup.1 and R.sup.2 is an alkyl group having less than 18 carbon atoms.

8. The method according to claim 1 wherein component (a) is selected from: (i) a quaternary ammonium salt additive; (ii) the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; (iii) the reaction product of a carboxylic acid-derived acylating agent and an amine; (iv) the reaction product of a carboxylic acid-derived acylating agent and hydrazine; (v) a salt formed by the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine; (vi) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride and an amine compound or salt which product comprises at least one amino triazole group; and (vii) a polyalkylene substituted amine.

9. The method according to claim 1 wherein component (a) is selected from: (i) a quaternary ammonium salt additive; (ii) the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; and (iii) the reaction product of a carboxylic acid-derived acylating agent and an amine.

10. The method according to claim 1 wherein component (a) is selected from one or more of: a quaternary ammonium salt additive formed by reacting methyl salicylate or dimethyl oxalate with the reaction product of a polyisobutylene-substituted succinic anhydride having a PIB number average molecular weight of 700 to 1300 and dimethylaminopropylamine; the Mannich reaction product of dodecylphenol, formaldehyde and either ethylene diamine or tetraethylpentamine; and the reaction product of a polyisobutenyl substituted succinic acid/anhydride having a PIB molecular weight (Mn) of 500 to 1300 and a polyethylene polyamine having 1 to 9 amino groups and 1 to 8 ethylene groups.

11. The method according to claim 1 wherein component (b) comprises at least one wax antisettling additive (x) and at least one middle distillate flow improver (y).

12. The method according to claim 1 wherein component (b) comprises a wax antisettling additive (x) which is the reaction product of (I) a compound containing the segment —NR.sup.3R.sup.4 where R.sup.3 represents a group containing from 4 to 44 carbon atoms and R.sup.4 represents a hydrogen atom or a group R.sup.3, and (II) a carboxylic acid having from 1 to 4 carboxylic acid groups or a reactive equivalent thereof.

13. The method according to claim 1 wherein component (b) comprises a wax antisettling additive (x) which is the reaction product of di(hydrogenated) tallow amine (I) and phthalic acid or its acid anhydride (II).

14. The method according to claim 1 wherein component (b) comprises a middle distillate flow improver (y) which is a copolymer of ethylene and an olefinically unsaturated compound.

15. The method according to claim 1 wherein component (b) comprises a middle distillate flow improver (y) which, in addition to ethylene, contains 1 to 23 mol %, of olefinically unsaturated compounds as co-monomers.

16. (canceled)

17. The composition according to claim 3 wherein additive (c) is prepared by copolymerising vinyl ester monomers and dialkyl fumarate monomers.

18. The composition according to claim 3 wherein R is methyl.

19. The composition according to claim 3 wherein each of R.sup.1 and R.sup.2 is an alkyl group having less than 18 carbon atoms.

20. The composition according to claim 4 wherein additive (c) is prepared by copolymerising vinyl ester monomers and dialkyl fumarate monomers.

21. The composition according to claim 4 wherein R is methyl.

22. The composition according to claim 4 wherein each of R.sup.1 and R.sup.2 is an alkyl group having less than 18 carbon atoms.

Description

EXAMPLES

[0278] In the examples, the following additive are dosed into middle distillate fuels:

[0279] A—an ethylene vinyl acetate copolymer comprising 30 to 32% wt % vinyl acetate units and having a number average MW of approximately 4-5000 supplied in aromatic solvent.

[0280] B—the reaction product of 2 moles di(hydrogenated) tallow amine and 1 mole phthalic anhydride reacted to form the half amide half ammonium salt supplied in aromatic solvent.

[0281] C—a copolymer of a 1:1 mole ratio of vinyl acetate and the diester of fumaric acid and tetradecanol having a number average MW of approximately 10,000 supplied in aromatic solvent.

[0282] D—the reaction product of a polyisobutenyl succinic anhydride with a PIB number average molecular weight of 750 and a mixture of polyethylene polyamines corresponding to tetraethylenepentamine reacted to form the polyisobutylene succinimide supplied in aromatic solvent.

[0283] E—the Mannich reaction product of dodecyl phenol, formaldehyde and ethylene diamine supplied in aromatic solvent.

[0284] F—the reaction product of a polyisobutene-substituted succinic anhydride with a PIB number average molecular weight of 1000 and dimethylamino propylamine reacted to form an imide and then quaternised by reaction with methyl salicylate supplied in aromatic solvent.

[0285] G—an ethylene vinyl acetate copolymer comprising 28 wt % vinyl acetate units and having a number average MW of approximately 3-4000 supplied in aromatic solvent.

[0286] H—a copolymer of a 1:1 mole ratio of vinyl acetate and the diester of fumaric acid and tetradecanol with a number average MW of approximately 21,000 supplied in aromatic solvent.

[0287] I (Comparative)—a copolymer of α olefin and behenyl maleate supplied in aromatic solvent.

[0288] J (Comparative)—C16/18 diester of C24/26 alpha olefin maleic anhydride copolymer supplied in aromatic solvent.

[0289] K (Comparative)—a C16/C18 alkyl imide of C14/C16 α olefin maleic anhydride copolymer supplied in aromatic solvent.

[0290] L—a copolymer of a 1:1 mole ratio of vinyl acetate and the diester of fumaric acid and dodecanol with a number average MW of approximately 30,000 supplied in aromatic solvent.

[0291] M—a copolymer of a 1:1 mole ratio of vinyl acetate and the diester of fumaric acid and dodecanol with a number average MW of approximately 33,000 supplied in aromatic solvent.

Example 1

[0292] Fuel compositions were prepared by adding the amounts as specified in Table 4 and Table 5 to a fuel composition as described below.

[0293] Compositions 1 to 10 were prepared in Fuel 1, a middle distillate fuel composition having a specification which corresponds to EN 590 and having properties shown in Table 1.

[0294] Compositions 11 and 12 were prepared in Fuel 2, a middle distillate fuel composition having a specification which corresponds to EN 590 and having properties shown in Table 2.

[0295] Compositions 13 to 16 were prepared in Fuel 3, a middle distillate fuel composition having a specification which corresponds to EN 590 and having properties shown in Table 3 blended with 7% vol Fatty Acid Methyl Ester to give a fuel having a cloud point of −9° C. and a CFPP of −9° C.

TABLE-US-00001 TABLE 1 Properties of Fuel 1 Test Units Results Density g/cm3 0.8386 Cloud Point ° C. −6 CFPP ° C. −8 Distillation IBP ° C. 170.6 10% ° C. 195.7 20% ° C. 208.3 30% ° C. 226.1 40% ° C. 243.8 50% ° C. 261.2 60% ° C. 279.5 70% ° C. 298.3 80% ° C. 316.5 90% ° C. 335.3 FBP ° C. 358.8

TABLE-US-00002 TABLE 2 Properties of Fuel 2 Test Units Results Density g/cm3 0.8312 Cloud Point ° C. −8.5 CFPP ° C. −10 Distillation IBP ° C. 166 10% ° C. 205 20% ° C. 223 30% ° C. 237 40% ° C. 251 50% ° C. 267 60% ° C. 283 70% ° C. 299 80% ° C. 317 90% ° C. 338 FBP ° C. 362

TABLE-US-00003 TABLE 3 Properties of Fuel 3 Test Units Results Density g/cm3 0.8312 Cloud Point ° C. −7.5 CFPP ° C. −10 Distillation IBP ° C. 168 10% ° C. 205 20% ° C. 221 30% ° C. 237 40% ° C. 251 50% ° C. 267 60% ° C. 282 70% ° C. 299 80% ° C. 317 90% ° C. 338 FBP ° C. 360

TABLE-US-00004 TABLE 4 Additive concentration (ppm active) Composition A B C D E F G 1 280 62.4 0 180 0 0 0 2 280 62.4 0 0 195 0 0 3 280 62.4 0 0 0 180 0 4 280 62.4 50 180 0 0 0 5 280 62.4 20 0 195 0 0 6 280 62.4 20 0 0 180 0 7 280 62.4 0 0 61.7 69.0 0 8 280 62.4 20 0 61.7 69.0 0 9 280 62.4 0 0 26.0 36.0 0 10 280 62.4 20 0 26.0 36.0 0 11 0 14.4 0 0 26.0 36.0 69.1 12 0 14.4 5 0 26.0 36.0 69.1

TABLE-US-00005 TABLE 5 Additive concentration (ppm active) Compo- I J K sition B G E F H comp comp comp L M 13 24.0 115.2 61.7 69.0 10 14 24.0 115.2 61.7 69.0 10 15 24.0 115.2 61.7 69.0 10 16 24.0 115.2 61.7 69.0 10 17 24.0 115.2 61.7 69.0 10 18 24.0 115.2 61.7 69.0 10

Example 2

[0296] Fuel compositions 1 to 17 were tested in a short sediment test according to procedure A and/or procedure B. Results are shown in Table 6

[0297] Procedure A

[0298] 450 g of base fuel is mixed with the appropriate amount of additive and the cloud point of the treated fuel is determined. 500 ml of the treated fuel is transferred into a 500 ml measuring cylinder and cooled in a climate chamber or cooling bath to the test temperature and then held at that temperature for 16 hours. After the 16 hour period the upper 80% and the lower 20% of the fuel are separated and heated to redissolve the precipitated wax. The cloud point of the two portions is determined. ACP is recorded as the difference between the cloud point of the upper 80% and that of the lower 20% portion of the fuel.

[0299] Procedure B

[0300] 150 g of base fuel is mixed with the appropriate amount of additive and stored at 40° C. for one hour. 100 ml is transferred into a 100 ml graduated cylinder. The cloud point of the treated fuel is determined. The sample is cooled in a cooling bath/climate chamber to the test temperature and then held at that temperature for 16 hours. After the 16 hour period, appearance of the fuel and the amount of sediment is recorded. The upper 50% and the lower 50% of the fuel are separated and the bottom 50% is stored at 40° for 1 hour and the cloud point is determined. ACP is recorded as the difference between the cloud point of the lower 50% portion of the fuel and the original cloud point of the treated fuel prior to cooling.

TABLE-US-00006 TABLE 6 (A) CP (B) CP (C) CP Test Treated Top Bottom (C) − (B) (C) − (A) Temp fuel Layer Layer ΔCP ΔCP Composition Procedure (° C.) (° C.) (° C.) (° C.) (° C.) (° C.) Appearance Sediment Result 1 A −13 −5.3 −8.3 −0.3 8.0 Fail 2 A −13 −5.2 −8.0 −0.2 7.8 Fail 3 A −13 −6.1 −7.1 −1.0 6.1 Fail 4 A −13 −6.4 −7.3 −5.2 2.1 Pass 5 A −13 −6.4 −6.8 −5.6 1.2 Pass 6 A −13 −6.1 −6.6 −5.2 1.4 Pass 7 A −13 −5.9 −6.6 −0.9 5.7 Fail 8 A −13 −6.4 −6.8 −5.2 1.6 Pass 9 A −13 −5.2 −6.7 −1.2 5.5 Fail 10 A −13 −6.0 −6.3 −5.4 0.9 Pass 11 B −14.5 −8.5 −4.5 4.0 clear 16 ml Fail 12 B −14.5 −8.5 −7.5 1.0 turbid none Pass 12 A −14.5 −8.5 −8.0 −7.0 1.0 turbid none Pass 13 B −15 −8.5 −8.0 0.5 turbid none Pass 14 B −15 −8.0 −3.0 5.0 flocculated 28 ml Fail 15 B −15 −8.5 −4.0 4.5 flocculated 26 ml Fail 16 B −15 −9.0 −4.5 4.5 almost clear 10 ml Fail 17 B −15 −8.0 −8.0 0.0 turbid trace Pass 18 B −15 −8.0 −7.5 0.5 turbid trace Pass