U.S. patent application number 14/421628 was filed with the patent office on 2015-11-05 for additives for improving the resistance to wear and lacquering of vehicle fuels of the gas oil or bio gas oil type.
This patent application is currently assigned to TOTAL MARKETING SERVICES. The applicant listed for this patent is TOTAL MARKETING SERVICES. Invention is credited to Thomas DUBOIS.
Application Number | 20150315506 14/421628 |
Document ID | / |
Family ID | 47351832 |
Filed Date | 2015-11-05 |
United States Patent
Application |
20150315506 |
Kind Code |
A1 |
DUBOIS; Thomas |
November 5, 2015 |
ADDITIVES FOR IMPROVING THE RESISTANCE TO WEAR AND LACQUERING OF
VEHICLE FUELS OF THE GAS OIL OR BIO GAS OIL TYPE
Abstract
The present disclosure relates to anti-lacquering additives for
vehicle fuels of the gas oil or bio gas oil type having a sulphur
content less than or equal to 500 ppm by mass. These additives also
improve the lacquering resistance of the higher-grade vehicle fuels
of gas oil or bio gas oil type having a sulphur content less than
or equal to 500 ppm by mass.
Inventors: |
DUBOIS; Thomas; (Lyon,
FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOTAL MARKETING SERVICES |
Puleaux |
|
FR |
|
|
Assignee: |
TOTAL MARKETING SERVICES
Puteaux
FR
|
Family ID: |
47351832 |
Appl. No.: |
14/421628 |
Filed: |
August 20, 2013 |
PCT Filed: |
August 20, 2013 |
PCT NO: |
PCT/EP2013/067311 |
371 Date: |
February 13, 2015 |
Current U.S.
Class: |
123/1A ; 44/348;
44/351; 549/478; 554/223 |
Current CPC
Class: |
C10L 1/18 20130101; C10L
2200/0259 20130101; C10L 1/224 20130101; C10L 1/191 20130101; C10L
1/22 20130101; C10L 10/04 20130101; C10L 2270/026 20130101; C10L
2200/0476 20130101; C10L 1/1881 20130101; C10L 1/236 20130101 |
International
Class: |
C10L 10/04 20060101
C10L010/04; C10L 1/22 20060101 C10L001/22; C10L 1/18 20060101
C10L001/18 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 22, 2012 |
FR |
FR1257939 |
Claims
1. Additives for limiting the soap and/or varnish deposits in
internal parts of injection systems of engines for (bio) gas oil
type vehicle fuels, having a sulphur content less than or equal to
500 ppm by mass, comprising at least 50% by mass of partial polyol
ester(s), the polyol esters comprising x ester units, y
hydroxylated units and z ether units, x, y and z being integers
such that x varies from 1 to 10, y varies from 1 to 10, and z
varies from 0 to 6.
2. Additives according to claim 1, wherein the polyol esters are
obtained by esterification of fatty acid(s) and linear and/or
branched polyols optionally comprising (hetero)cycles of 5 to 6
atoms, bearing hydroxyl functions.
3. Additives according to claim 1, wherein the polyol esters, the
ester unit, hydroxylated unit and ether unit distribution is such
that x varies from 1 to 4, y varies from 1 to 7 and z varies from 1
to 3.
4. Additives according to claim 1, wherein the polyols R are chosen
from the linear polyols comprising more than three hydroxyl
functions and the polyols comprising at least one heterocycle of 5
or 6 atoms, optionally substituted by hydroxyl groups, these
polyols being able to be used alone or in a mixture.
5. Additives according to claim 1, wherein R is a polyol comprising
at least four units presented in formula (I) below;
H--(OCH.sub.2).sub.p--(CHOH).sub.q--(CH.sub.2OH) (I) with p and q
being integers, p being equal to or greater than 0, q is greater
than 2, these numbers not being able to exceed 10.
6. Additives according to claim 1, wherein R is a polyol comprising
at least four units presented in general formula (II) below:
H--(OCH.sub.2).sub.p--(CR1R2).sub.q-(CH.sub.2OH) (II) with p and q
being integers, p being equal to or greater than 0, q is greater
than 1, these numbers not being able to exceed 5, R1 and R2 are
identical or different and represent either the hydrogen atom, or a
--CH3 or --C2H5 group, or a --CH2OH group.
7. Additives according to claim 1, wherein R is a polyol comprising
at least two heterocycles of 4 or 5 carbon atoms and an oxygen
atom, connected by the formation of an acetal bond between a
hydroxyl function of each ring, those heterocycles being optionally
substituted by hydroxyl groups.
8. Additives according to claim 1, wherein the partial polyol
esters are chosen from the partial sorbitan esters, used alone or
in a mixture.
9. Additives according to claim 1, wherein the polyols R are chosen
from the group comprising erythritol, xylitol, arabitol, ribitol,
sorbitol, malitol, isomalitol, lactitol, sorbitan, volemitol,
mannitol, pentaerythritol, 2-hydroxymethyl-1,3-propanediol,
1,1,1-tri(hydroxymethyl)ethane, trimethylolpropane and
carbohydrates such as sucrose, fructose, maltose, glucose and
saccharose.
10. Additives according to claim 1, wherein the partial polyol
esters are obtained by reaction of the polyols with at least one
fatty acid with a chain length varying from 10 to 24 carbon atoms
and/or at least one diacid substituted by at least one polymer, for
example poly(iso)butene comprising from 8 to 100 carbon atoms.
11. Additives according to claim 10, wherein the partial polyol
esters are chosen from the group constituted by monoesters or
diesters obtained from mono acids chosen from the stearic,
isostearic, linolenic, oleic, linoleic, behenic, arachidonic,
ricinoleic, palmitic, myristic, lauric, capric acids, and mixtures
thereof and/or diacids chosen from the alkyl- or alkenylsuccinic,
alkyl- or alkenylmaleic acids.
12. A method for limiting the soap and/or varnish deposits in the
internal parts of the injection systems of the engines for the
(bio) gas oil vehicle fuels, having a sulphur content less than or
equal to 500 ppm by mass the method comprising using the additive
as defined in claim 1.
13. The method according to claim 12, further comprising
incorporating the additive in the (bio) gas oil vehicle fuels for
the engines.
14. The method according to claim 12, wherein the engines are
direct injection engines.
15. Compositions of (bio) gas oil vehicle fuel having a sulphur
content less than or equal to 500 ppm by mass, comprising: at least
one additive comprising at least 50% by mass of partial polyol
ester(s), the polyol esters comprising x ester units, y
hydroxylated units and z ether units, x, y and z being integers
such that x varies from 1 to 10, y varies from 1 to 10, and z
varies from 0 to 6; and optionally at least one or more other
functional additives.
16. The compositions of (bio) gas oil vehicle fuel according to
claim 15, further comprising up to 10% by mass of one or more
additional additives.
17. The compositions according to claim 15, wherein the fuel is
higher-grade (bio) gas oil vehicle fuel containing at least 50 ppm
by mass of deposit reducers/detergents/dispersants, and containing
at least 20 ppm by mass of the additive, and optionally at least
one or more other functional additives.
18. The compositions of (bio) gas oil vehicle fuel according to
claim 15 having a mono- and di-ester concentration varying from 20
to 1000 ppm by mass m/m.
19. (canceled)
20. (canceled)
21. A process comprising: limiting soap and/or varnish deposits in
internal parts of an injection system of an engine for (bio) gas
oil vehicle fuel (diesel engine) having a sulphur content less than
or equal to 500 ppm by mass; and combustion in the engine of a
composition comprising at least one additive comprising at least
50% by mass of partial polyol ester(s), the polyol esters
comprising x ester units, y hydroxylated units and z ether units,
x, y and z being integers such that x varies from 1 to 10, y varies
from 1 to 10, and z varies from 0 to 6; and optionally at least one
or more other functional additives.
22. The process according to claim 21, wherein the engine is a
direct injection engine.
23. The process according to claim 21, further comprising
preventing formation of the soap and/or varnish deposits in the
internal parts of the injection system of the engine, in order to
keep the engine clean.
24. The process according to claim 21, further comprising removing
the soap and/or varnish deposits in the internal parts of the
injection system of the engine, for a curative action of cleaning
up the engine.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a National Phase Entry of International
Application No. PCT/EP2013/067311, filed on Aug. 20, 2013, which
claims priority to French Patent Application Serial No. 1257939,
filed on Aug. 22, 2012, both of which are incorporated by reference
herein.
BACKGROUND AND SUMMARY
[0002] A subject of the present invention is additives making it
possible to limit the formation of soaps and/or varnishes in the
internal parts of the injection systems of engines for (bio)gas oil
type vehicle fuels, i.e. in particular to increase their resistance
to lacquering.
[0003] Gas oil or diesel is a vehicle fuel for diesel engines
(compression engines) comprising middle distillates with a boiling
point comprised between 100 and 500.degree. C. A gas oil can be
constituted by a mixture of middle distillates of fossil origin and
biofuels. By biofuel, is meant the vehicle fuels obtained from
organic matter (biomass), as opposed to the vehicle fuels
originating from fossil resources. There can be mentioned, as
examples of known biofuels, the bio gas oils (or also called
biodiesel) and the alcohols.
[0004] Biodiesel or bio gas oil is an alternative to standard
vehicle fuel for diesel engines. This biofuel is obtained from
vegetable or animal oil (including used cooking oils) converted by
a chemical process called transesterification causing this oil to
react with an alcohol in order to obtain fatty acid esters. With
methanol and ethanol, fatty acid methyl esters (FAMEs) and fatty
acid ethyl esters (FAEEs) are obtained respectively.
[0005] Mixtures of middle distillates of fossil origin and bio gas
oil are denoted by the letter "B" followed by a number indicating
the percentage of bio gas oil contained in the gas oil. Thus, a B99
contains 99% bio gas oil and 1% middle distillates of fossil
origin, and B20 contains 20% bio gas oil and 80% middle distillates
of fossil origin etc.
[0006] Gas oil vehicle fuels of the B0 type, which do not contain
oxygen-containing compounds are therefore distinguished from bio
gas oil vehicle fuels of the Bx type which contain x % (v/v)
vegetable oil esters or fatty acid esters, most often methyl esters
(FAME or VOME). When the bio gas oil is used alone in the engines,
the vehicle fuel is denoted by the term B100. In the remainder of
the present application, the term (bio) gas oil is used to identify
the B0 or Bx type vehicle fuels for diesel engines (compression
engines).
[0007] In many countries the sulphur content of (bio) gas oil
vehicle fuels has been subject to a very significant reduction for
environmental reasons, in particular in order to reduce the
SO.sub.2 emissions. For example in Europe, the maximum sulphur
content of road gas oil type vehicle fuels is currently 10 ppm by
mass.
[0008] As well as reducing the sulphur content, the methods of
preparation of low-sulphur gas oil or diesel vehicle fuel bases,
for example hydrotreatment methods, also reduce the polycyclic
aromatic compounds and polar compounds contained in these gas oil
vehicle fuel bases for diesel engines. It is known that gas oil or
diesel vehicle fuels having a low (less than 100 ppm) or even very
low sulphur content have a reduced ability to lubricate the engine
fuel injection system, which results for example in early failure
of the engine fuel injection pump during the lifetime of the
engine, failure occurring for example in high-pressure vehicle fuel
injection systems, such as high-pressure rotary distributors,
in-line pumps and combined pump-injector units. In order to
compensate for the loss of compounds ensuring the lubricating
character of these vehicle fuels, numerous lubricity and/or
anti-wear and/or friction modifying additives have been introduced
into the fuels on the market. Their characteristics are broadly
described in the patents EP 915944, EP 839174 and EP680506.
[0009] It is known that the diesel vehicle fuels on the market must
meet national or supranational specifications (for example standard
EN 590 for diesel vehicle fuels in the EU). For commercial vehicle
fuels, there is no legal obligation regarding the incorporation of
so-called performance additives (chemical compounds incorporated in
fuels to improve their properties, for example detergent additives,
friction-reducing additives, anti-corrosion additives, anti-foaming
additives and additives for improving low temperature performance);
the oil companies and the distributors are free to add or not add
additives to their vehicle fuels. From a commercial standpoint, in
the field of distribution of fuels, a distinction is made between
the "standard or entry-level" fuels, with little or no additives,
and higher-grade fuels, in which one or more additives are
incorporated to improve their performance (above the regulation
performance). Within the meaning of the present invention, by
higher-grade vehicle fuel of the gas oil or bio gas oil type is
meant any gas oil or bio gas oil vehicle fuel to which at least 50
ppm by mass of deposit reducing and/or detergent and/or dispersant
additives have been added.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a photograph of a diesel engine injector with
high-pressure direct injection;
[0011] FIG. 2 is a photograph of a needle of a diesel engine
injector with direct injection, fouled with soap and/or varnish
type deposits ("lacquering");
[0012] FIG. 3 is a photograph of a nozzle of a diesel engine
injector with indirect injection, fouled with coking type deposits;
and
[0013] FIG. 4 is a photograph of a needle of a diesel engine
injector with direct injection, fouled with soap and/or varnish
type deposits ("lacquering").
DETAILED DESCRIPTION
[0014] As shown in FIGS. 1 and 2, it has been found that during the
use of certain higher-grade (bio) gas oil vehicle fuels, deposits 1
appear on the needles 2 of the injector 3 of the injection systems
of diesel engines, in particular those of Euro 3 to Euro 6 type.
Thus, the use of anti-wear and/or friction modifying and/or
anti-coking type deposit additives have sometimes exhibited
unsatisfactory, or even very unsatisfactory, resistance to
lacquering. This results in the formation of deposit 1 generally
covered by the term "lacquering", which will be used hereinafter,
or the acronym IDID (internal diesel injector deposits).
[0015] Within the meaning of the present invention, the lacquering
phenomenon does not relate to the deposits which are present on the
outside of the injection system 5 or 5' (FIGS. 1 and 3) and which
are associated with coking which gives rise to fouling and partial
or total blocking of the injection nozzles 4 or 4' (nozzle "coking"
or "fouling"). Lacquering and coking are two phenomena clearly
distinguished by: [0016] the causes of these deposits, [0017] the
conditions for the appearance of these deposits and, [0018] the
site where these deposits are produced. Coking is a phenomenon
which appears only downstream of a diesel injection system.
[0019] As shown in FIG. 3, the deposits 5' formed are characterized
in that they are constituted by pyrolysis of the hydrocarbons
entering the combustion chamber and have the appearance of
carbonaceous deposits. In the case of high-pressure direct
injection diesel engines, it has been found that the coking
tendency is much less marked. This coking is simulated in the CEC
F098-08 DW10B standard engine test, in particular when the vehicle
fuel tested is contaminated with metallic zinc.
[0020] In the case of indirect injection engines, the injection of
the vehicle fuel is not carried out directly in the combustion
chamber as in the case of direct injection engines. As described
for example in U.S. Pat. No. 4,604,102, there is a prechamber
before the combustion chamber into which the fuel is injected. The
pressure and the temperature in a prechamber are below those of a
combustion chamber of direct injection engines.
[0021] Under these conditions, the pyrolysis of the vehicle fuel
produces carbonaceous particles which are deposited on the surface
of the nozzles 4' of the injectors ("throttling diesel nozzle") and
block the apertures 6 of the nozzles 4' (FIG. 3). Only the surfaces
of the nozzle 4' exposed to the combustion gases are at risk of
carbon deposits (coking). In terms of performance, the phenomenon
of coking causes a loss of engine power.
[0022] Lacquering is a phenomenon that appears only in direct
injection diesel engines and only occurs upstream of the combustion
chamber, i.e. in the injection system. As shown in FIGS. 1 and 2,
the injectors 3 of direct injection diesel engines comprise a
needle 2 the lift of which allows precise control of the quantity
of fuel injected at high pressure directly into the combustion
chamber.
[0023] The lacquering causes the appearance of deposits 1 which
appear specifically at the level of the needles 2 of the injectors
3 (FIGS. 1 and 2). The lacquering phenomenon is linked to the
formation of soap and/or varnish in the internal parts of the
injection systems of engines for (bio) gas oil type fuels. The
lacquering deposit 1 can be located on the end 4 of the needles 2
of the injectors 3, both on the head and on the body of the needles
2 of the vehicle fuel injection system but also throughout the
entire needle lift control system (valves not shown) of the
injection system. This phenomenon is particularly marked in the
case of engines using higher-grade (bio) gas oil vehicle fuels.
When these deposits are present in large quantities, the mobility
of the needle 2 of the injector 3 fouled with these deposits 1 is
compromised. This lacquering phenomenon can eventually generate a
loss of flow rate of vehicle fuel injected and therefore a loss of
engine power.
[0024] Moreover, unlike coking, lacquering can also cause an
increase in engine noise and sometimes starting problems. Indeed,
the parts of the needles 2 fouled by the deposits of soap and/or
varnish 1 can adhere to the internal walls of the injector 3. The
needles 2 are then blocked and the fuel can no longer pass
through.
[0025] Generally a distinction is made between 2 types of deposits
of the lacquering type:
[0026] 1. deposits that are rather whitish and powdery; on
analysis, it is found that these deposits consist essentially of
soaps of sodium (sodium carboxylates, for example) and/or calcium
(type 1 deposits);
[0027] 2. organic deposits resembling coloured varnishes localized
on the needle body (type 2 deposits).
[0028] Regarding the type 1 deposits, there are many possible
sources of sodium in bio gas oil vehicle fuels of the Bx type:
[0029] catalysts for transesterification of vegetable oils for
producing esters of the fatty acid (m)ethyl ester type such as
sodium formate;
[0030] another possible source of sodium can be from the corrosion
inhibitors used when petroleum products are conveyed in certain
pipes, such as sodium nitrite;
[0031] finally, accidental exogenous pollution, via water or air
for example, can contribute to the introduction of sodium into
vehicle fuels (sodium being a very widely occurring element).
[0032] There are many possible sources of acids in vehicle fuels of
the Bx type, for example: [0033] residual acids in biofuels (see
standard EN14214 which fixes a maximum permitted level of acids)
[0034] corrosion inhibitors used in the conveyance of petroleum
products in certain pipes such as DDSA (dodecenylsuccinic
anhydride) or HDSA (hexadecenylsuccinic anhydride) or some of their
functional derivatives such as acids.
[0035] With regard to type 2 organic deposits, some publications
state that they may in particular result from reactions between
deposit reducers/dispersants used to prevent coking (for example
PIBSI type detergents which are derivatives of polyamines) and
acids (which would be present inter alia as fatty acid ester
impurities in bio gas oil). In the publication SAE 880493, Reduced
Injection Needle Mobility Caused by Lacquer Deposits from Sunflower
Oil, the authors M Ziejewski and H J Goettler describe the
lacquering phenomenon and its harmful consequences for the
operation of engines operating with sunflower oils as vehicle fuel.
In the publication SAE 2008-01-0926, Investigation into the
Formation and Prevention of Internal Diesel Injector Deposits, the
authors J Ullmann, M Geduldig, H Stutzenberger (Robert Bosch GmbH)
and R Caprotti, G Balfour (Infineum) also describe the reactions
between acids and deposit reducers/dispersants to explain the type
2 deposits.
[0036] Moreover, in the publication SAE International,
2010-01-2242, Internal Injector Deposits in High-Pressure Common
Rail Diesel Engines, the authors S. Schwab, J. Bennett, S. Dell, J.
Galante-Fox, A. Kulinowski and Keith T. Miller explain that the
internal parts of the injectors are generally covered with a
slightly coloured deposit which is visible to the naked eye. Their
analyses made it possible to determine that it mainly comprised
sodium salts of alkenyl (hexadecenyl or dodecenyl) succinic acids;
the sodium originating from dehydrating agents, from caustic
solutions used in the refinery, from tank bottom water or from
seawater, and the succinic diacids being used as corrosion
inhibitors or present in multifunctional additive packages. Once
formed, these salts are insoluble in low-sulphur diesel fuels, and
as they are in the form of fine particles they pass through gas oil
filters and are deposited inside the injectors. In this
publication, the development of an engine test is described, making
it possible to reproduce the deposits. This publication emphasizes
that only the diacids generate deposits, in contrast to
monocarboxylic acids or the neutral esters of organic acids.
[0037] In the publication SAE International, 2010-01-2250, Deposit
Control in Modern Diesel Fuel Injection System, the authors, R.
Caprotti, N. Bhatti and G. Balfour, also investigate the same type
of internal deposits in the injectors and assert that the
appearance of deposits is not linked specifically to one type of
vehicle fuel (B0 or containing FAME(Bx)) nor to vehicles of one
type (light vehicles or heavy goods vehicles) equipped with modern
motorizations (common rail). They demonstrate the performance of a
new deposit reducer/dispersant, effective on all types of deposits
(coking and lacquering).
[0038] The present invention proposes additives with preventive and
curative effects, making it possible to limit the soap and/or
varnish deposits in the internal parts of the injection systems,
i.e. to improve resistance to the phenomenon of lacquering in
engines using higher-grade (bio) gas oil and/or (bio) diesel type
vehicle fuels, the sulphur content of which is less than or equal
to 500 ppm by mass, and which comprise at least 50 ppm by mass of
deposit reducer(s) and/or detergents and/or dispersant(s). These
additives therefore prevent these deposits to form (preventive),
and allow when they are formed, to be removed by render the
injectors cleaner (curative).
[0039] These problems of the resistance to lacquering of (bio) gas
oil type vehicle fuels are solved by the use of at least one
additive which comprises at least 50% by mass of partial polyol
ester(s), said polyol esters comprising x ester units, y
hydroxylated units and z ether units, x, y and z being integers
such that x varies from 1 to 10, y varies from 1 to 10, and z
varies from 0 to 6, preferably x varies from 1 to 10, y varies from
3 to 10, and z varies from 0 to 6. The synthesis of partial polyol
esters is known per se; they can for example be prepared by
esterification of fatty acid(s) and linear and/or branched polyols
optionally comprising (hetero)cycles of 5 to 6 atoms bearing
hydroxyl functions. The product(s) originating from this
esterification reaction comprise(s) a distribution of ester units,
hydroxylated units and ether units such that x varies from 1 to 4,
y varies from 1 to 7 and z varies from 1 to 3. Generally this type
of synthesis leads to a mixture of mono-, di-, tri- and optionally
tetra-esters as well as small quantities of fatty acid(s) and
polyols which have not reacted.
[0040] According to an embodiment, the polyol esters are obtained
by esterification of fatty acid(s) and of linear and/or branched
polyols optionally comprising heterocycles of 4 to 5 carbon atoms
and an oxygen atom, bearing hydroxyl functions. Within the
framework of the present invention, the polyols will be chosen from
the linear polyols comprising more than three hydroxyl functions
and the polyols comprising at least one (hetero)cycle of 5 or 6
atoms, preferably heterocycles of 4 to 5 carbon atoms and an oxygen
atom, optionally substituted by hydroxyl groups, these polyols
being able to be used alone or in a mixture. In the remainder of
the present discussion, these polyols are referenced R in the
formulations mentioned below.
[0041] Among the polyols R, the polyols with linear or branched
hydrocarbon chains comprise at least four units represented in
formula (I) below:
H--(OCH.sub.2).sub.p--(CHOH).sub.q--(CH.sub.2OH) (I)
With p and q being integers, p being equal to or greater than 0, q
is greater than 2, these numbers not being able to exceed 10.
[0042] Among the polyols R, the polyols with linear or branched
hydrocarbon chains comprise at least four units represented in
formula (II) below:
H--(OCH.sub.2).sub.p--(CR1R2).sub.q-(CH.sub.2OH) (II)
With p and q being integers, p being equal to or greater than 0, q
is greater than 1, these numbers not being able to exceed 5, R1 and
R2 are identical or different and represent either the hydrogen
atom, or a --CH.sub.3 or --C.sub.2H.sub.5 group or a --CH.sub.2--OH
group.
[0043] Among the polyols R, some comprise at least one
(hetero)cycle of 4 or 5 carbon atoms and an oxygen atom, optionally
substituted by hydroxyl groups and correspond to general formula
(III) below:
##STR00001##
[0044] with s and t being integers, and when s is equal to 1, t is
equal to 3 and when s is zero, t is equal to 4.
[0045] Among the polyols R, some comprise at least two heterocycles
of 4 or 5 carbon atoms and one oxygen atom connected by the
formation of an acetal bond between a hydroxyl function of each
ring, those heterocycles being optionally substituted by hydroxyl
groups. Preferably, the polyols are chosen from the group
comprising erythritol, xylitol, D-arabitol, L-arabitol, ribitol,
sorbitol, malitol, isomalitol, lactitol, sorbitan, volemitol,
mannitol, pentaerythritol, 2-hydroxymethyl-1,3-propanediol,
1,1,1-tri(hydroxymethyl)ethane, trimethylolpropane and
carbohydrates such as sucrose, fructose, maltose, glucose and
saccharose, preferably sorbitan. According to a preferred variant,
the partial polyol esters are chosen from the partial sorbitan
esters, preferably sorbitan monooleate, used alone or in a
mixture.
[0046] The fatty acids from which the esters according to the
invention originate can be chosen from the fatty acids the chain
length of which varies from 10 to 24 carbon atoms and/or at least
one diacid substituted by at least one polymer, for example
poly(iso)butene comprising from 8 to 100 carbon atoms. They are
preferably chosen, in the case of the mono acids, from the stearic,
isostearic, linolenic, oleic, linoleic, behenic, arachidonic,
ricinoleic, palmitic, myristic, lauric and capric acids, and
mixtures thereof and, in the case of the diacids from the alkyl- or
alkenylsuccinic, alkyl- or alkenylmaleic acids. The fatty acids can
originate from the transesterification or the saponification of
vegetable oils and/or animal fats. The preferred vegetable oils
and/or animal fats are chosen according to their oleic acid
concentration. Reference may be made for example to Table 6.21 of
Chapter 6 of the publication Carburants & Moteurs by J. C.
Guibet and E. Faure, 2007 edition in which the compositions of
several vegetable oils and animal fats are given. The fatty acids
can also originate from tall oil fatty acids which comprise a
majority of fatty acids, typically greater than or equal to 90% by
mass as well as resin acids and unsaponifiables in a minority, i.e.
in quantities generally less than 10%.
[0047] Preferred additives according to the invention capable of
improving the lacquering resistance of higher-grade (bio)diesel
vehicle fuels comprise partial sorbitan esters. Other preferred
additives comprise at least 50% by mass of mono- and/or diester(s)
of isobutylenesuccinic acid and polyols according to one of
formulae I to III. Other preferred additives comprise at least 50%
by mass of mono- and/or diester(s) of monocarboxylic acids with 12
to 24 carbon atoms and polyols according to one of formulae I to
III.
[0048] The invention also relates to an additive package for (bio)
gas oil vehicle fuels containing at least one lacquering resistance
additive as defined previously and at least one or more other
functional additives, such as deposit reducers/dispersants,
anti-oxidants, combustion improvers, corrosion inhibitors, low
temperature performance additives (improving the cloud point,
sedimentation rate, filterability and/or low temperature flow),
colorants, emulsion breakers, metal deactivators, anti-foaming
agents, agents improving the cetane number, compatibilizing agents,
lubricity additives, anti-wear agents and/or friction modifiers,
and one or more solvents or co-solvents. The use of the additives
according to the invention makes it possible to improve the
lacquering resistance at the level of the fuel injectors, and thus
limit the formation (the deposit) of soap and/or varnish in the
presence of the additives such as the deposit reducers and/or
detergent and/or dispersants. The use of these additives in (bio)
gas oil vehicle fuels makes it possible to reduce the blockage rate
and deterioration in the fuel admission or injection system, in
particular on the injection pump.
[0049] The bio gas oil vehicle fuels (liquid fuels for compression
engines) can comprise middle distillates having a boiling point
comprised between 100 and 500.degree. C.; their incipient
crystallization temperature ICT is often above or equal to
-20.degree. C., in general comprised between -15.degree. C. and
+10.degree. C. These distillates are mixtures of bases that can be
selected for example from the distillates obtained by direct
distillation of gasoline or crude hydrocarbons, vacuum distillates,
hydrotreated distillates, distillates originating from the
catalytic cracking and/or hydrocracking of vacuum distillates, the
distillates resulting from ARDS (atmospheric residue
desulphurization) type conversion processes and/or visbreaking. The
(bio) gas oil vehicle fuels can also contain light cuts such as the
gasolines originating from distillation, catalytic or thermal
cracking units, alkylation, isomerization, desulphurization units
and steam cracking units.
[0050] Moreover, the (bio) gas oil vehicle fuels can contain novel
sources of distillates, among which there can be mentioned in
particular:
[0051] heavier cuts originating from the cracking and visbreaking
processes concentrated in heavy paraffins, comprising more than 18
carbon atoms,
[0052] synthetic distillates originating from gas conversion such
as those originating from the Fischer Tropsch process,
[0053] synthetic distillates resulting from the treatment of
biomass of vegetable and/or animal origin, such as in particular
NexBTL, alone or in a mixture,
[0054] coker gas oils,
[0055] alcohols, such as methanol, ethanol, butanols, ethers,
(MTBE, ETBE, etc) in general used in a mixture with the gasoline
vehicle fuels, but sometimes with heavier vehicle fuels of the gas
oil type,
[0056] vegetable and/or animal oils and/or their esters, such as
vegetable oil or fatty acid methyl or ethyl esters (VOME, FAME,
VOEE, FAEE),
[0057] hydrotreated and/or hydrocracked and/or hydrodeoxygenated
(HDO) vegetable and/or animal oils,
[0058] These novel vehicle fuel and fuel bases can be used alone or
in a mixture with conventional petroleum middle distillates as
vehicle fuel base(s); they generally comprise paraffin long chains
greater than or equal to 10 carbon atoms, preferably from C.sub.14
to C.sub.30. Within the framework of the present invention, the
(bio) gas oil vehicle fuels have a sulphur content less than or
equal to 500 ppm by mass, advantageously less than or equal to 100
ppm by mass, and capable of being reduced to a content less than or
equal to 50 ppm by mass, or even less than or equal to 10 ppm by
mass (this is the case of diesel fuels for current vehicles for
which the sulphur content according to European standard EN 590
currently in force must be less than or equal to 10 ppm by
mass).
[0059] The additives providing resistance to lacquering, i.e. to
the formation of soap and/or varnish in the internal parts of the
injection systems of engines for (bio) gas oil vehicle fuels
according to the invention can be incorporated in the vehicle fuels
up to a value of 10% by mass. Advantageously the concentration of
partial esters according to the invention in the final vehicle fuel
is comprised between 20 and 1000 ppm by mass and advantageously
between 30 and 200 ppm by mass, i.e. ppm by mass relative to the
total mass of the vehicle fuel with additives.
[0060] According to an embodiment, the higher-grade (bio) gas oil
compositions contain at least 20 ppm by mass of at least one
additive according to the invention and optionally at least one or
more other functional additives. Preferably, the concentration of
additives according to the invention in the composition, i.e. the
concentration of partial ester can vary from 20 to 1000 ppm by
mass, and more particularly from 30 to 200 ppm by mass m/m. Among
the other functional additives, the lacquering resistance additives
of the present invention can be used alone or in a mixture with
deposit reducers and/or detergents and/or dispersants,
anti-oxidants, combustion improvers, corrosion inhibitors, low
temperature performance additives (improving the cloud point,
sedimentation rate, filterability and/or low temperature flow),
colorants, emulsion breakers, metal deactivators, anti-foaming
agents, agents improving the cetane number, anti-wear and lubricity
additives and/or friction modifiers, co-solvents, compatibilizing
agents etc.
[0061] The other functional additive(s) can be chosen
non-limitatively from: [0062] combustion-improving additives; for
vehicle fuels of the gas oil type, there can be mentioned cetane
booster additives, in particular (but non-limitatively chosen from
alkyl nitrates, preferably 2-ethyl hexyl nitrate, aryl peroxides,
preferably benzyl peroxide, and alkyl peroxides, preferably di
tert-butyl peroxide; for vehicle fuels of the gasoline type, there
can be mentioned octane number improver additives; for fuel such as
domestic heating oil, heavy fuel oil, marine diesel oil, there can
be mentioned methyl cyclopentadienyl manganese tricarbonyl (MMT);
[0063] anti-oxidant additives, such as aliphatic, aromatic amines,
hindered phenols, such as BHT, BHQ; [0064] emulsion breakers or
demulsifiers; [0065] anti-static or conductivity improver
additives; [0066] colorants; [0067] anti-foaming additives, in
particular (but non-limitatively) chosen for example from
polysiloxanes, oxyalkylated polysiloxanes, and fatty acid amides
originating from vegetable or animal oils; examples of such
additives are given in EP 861 182, EP 663 000, EP 736 590; [0068]
the detergent or dispersant additives, in particular (but
non-limitatively) chosen from the group constituted by the amines,
succinimides, succinamides, alkenylsuccinimides, polyalkylamines,
polyalkyl polyamines, polyetheramines, Mannich bases; examples of
such additives are given in EP 938 535; [0069] anti-corrosion
additives such as ammonium salts of carboxylic acids; [0070]
chelating agents and/or metal sequestering agents, such as
triazoles, disalicylidene alkylene diamines, and in particular N,N'
bis(salicylidene)1,3-propane diamine; [0071] low temperature
performance additives and in particular additives for improving the
cloud point, in particular, (but non-limitatively) chosen from the
group constituted by the long-chain olefin/(meth)acrylic
ester/maleimide terpolymers, and the polymers of fumaric/maleic
acid esters. Examples of such additives are given in EP 71 513, EP
100 248, FR 2 528 051, FR 2 528 423, EP1 12 195, EP 1 727 58, EP
271 385, EP 291367; anti-sedimentation and/or dispersant additives
for paraffins in particular (but non-limitatively) chosen from the
group constituted by the (meth)acrylic acid/alkyl (meth)acrylate
copolymers amidified by a polyamine, alkenylsuccinimides derived
from polyamine, phthalamic acid and double-chain fatty acid
derivatives; alkyl phenol/aldehyde resins; examples of such
additives are given in EP 261 959, EP 593 331, EP 674 689, EP 327
423, EP 512 889, EP 832 172; U.S. Patent Publication No.
2005/0223631; U.S. Pat. No. 5,998,530; WO 93/14178;
multi-functional low temperature operability additives chosen in
particular from the group constituted by olefin- and alkenyl
nitrate-based polymers such as those described in EP 573 490;
[0072] other additives improving the low temperature performance
and the filterability (CFI), such as EVA and/or EVP copolymers;
[0073] metal passivators, such as triazoles, alkylated
benzotriazoles; [0074] acidity neutralizers such as cyclic
alkylamines; [0075] markers, in particular the markers mandated by
regulations, for example the colorants specific to each type of
vehicle fuel or fuel. [0076] fragrancing agents or agents for
masking odours, such as those described in EP 1 591 514; [0077]
lubricity additives, anti-wear agents and/or friction modifiers
other than those described above, in particular (but
non-limitatively) chosen from the group constituted by fatty acids
and their ester or amide derivatives, in particular glycerol
monooleate, and derivatives of mono- and polycyclic carboxylic
acids; examples of such additives are given in the following
documents: EP 680 506, EP 860 494, WO 98/04656, EP 915 944, FR2 772
783, FR 2 772 784.
[0078] The optional other additives are generally incorporated in
quantities varying from 50 to 1500 ppm m/m, i.e. ppm by mass
relative to the total mass of the vehicle fuel with additives.
[0079] These additives can be incorporated into the fuels following
any known method; by way of example, the additive or the mixture of
additives can be incorporated in concentrate form comprising the
additive(s) and a solvent, compatible with the (bio) diesel fuel,
the additive being dispersed or dissolved in the solvent. Such
concentrates in general contain from 20 to 95% by mass of solvents.
A person skilled in the art will easily adapt the concentration of
additives according to the invention as a function of any dilution
of the additive in a solvent, the possible presence of other
components originating for example from the esterification reaction
and/or other functional additives incorporated in the final vehicle
fuel. The solvents are organic solvents that generally contain
hydrocarbon solvents. By way of example of solvents, there can be
mentioned petroleum fractions, such as naphtha, kerosene, heating
oil; aliphatic and/or aromatic hydrocarbons such as hexane,
pentane, decane, pentadecane, toluene, xylene, and/or ethylbenzene
and alkoxyalkanols such as 2-butoxyethanol and/or mixtures of
hydrocarbons such as mixtures of commercial solvents such as for
example Solvarex 10, Solvarex LN, Solvent Naphtha, Shellsol AB,
Shellsol D, Solvesso 150, Solvesso 150 ND, Solvesso 200, Exxsol,
ISOPAR and optionally co-solvents or combatibilizing agents, such
as 2-ethylhexanol, decanol, isodecanol and/or isotridecanol.
[0080] The invention relates to the use of at least one additive
composition according to the invention incorporated in a vehicle
fuel of the higher-grade (bio) gas oil type for improving the
resistance to lacquering, i.e. fouling on the head and/or on the
body of the needles of the fuel injection system but also in the
whole needle lift control system (valves) of the injection system,
in particular for engines provided with high-pressure direct fuel
injection systems, with which most vehicles complying with the Euro
3 and more recent regulations are equipped. According to a
particular embodiment, the subject of the present invention also
relates to the use of a composition of (bio) gas oil vehicle fuel
as described above, in order to limit the soap and/or varnish
deposits in the internal parts of the injection systems of the
engines using said composition, preferably direct injection
engines, in particular high-pressure direct injection engines.
[0081] The subject of the present invention also relates to a
process for limiting the soap and/or varnish deposits in internal
parts of the injection system of an engine for (bio) gas oil
vehicle fuels (diesel engines) having a sulphur content less than
or equal to 500 ppm by mass, said process comprising the combustion
in said engine of a (bio) gas oil vehicle fuel composition as
defined above. Preferably, the process applies to direct injection
engines, in particular high-pressure direct injection engines.
Thus, the process according to the invention avoids and prevents
the formation of deposits of soap and/or varnish in the internal
parts of the injection system of the engine, in order to keep said
engine clean. Advantageously, the process according to the present
invention removes the soap and/or varnish deposited in the internal
parts of the injection system of the engine, for a curative action,
cleaning up the engine.
EXAMPLES
[0082] In order to test the performances of these additives
according to the invention, the inventors have also developed a
novel method that is reliable and robust for evaluating the
sensitivity of (bio) gas oil vehicle fuels, in particular those of
higher grade, to lacquering. This method, unlike the methods
described in the publications cited above, is not a laboratory
method but is based on engine tests and is therefore of industrial
interest and makes it possible to quantify the effectiveness of the
additives or of the additive compositions against lacquering.
[0083] The method for measuring lacquering developed by the
inventors is detailed below:
[0084] The engine used is a four-cylinder, 16-valve, high-pressure
injection common rail diesel engine with a cylinder capacity of
1500 cm.sup.3 and a power of 80 hp: regulation of the fuel
injection pressure takes place in the high-pressure part of the
pump.
[0085] The power point is used over a period of 40 h at 4000 rpm;
the position of the injector in the chamber has been lowered by 1
mm relative to its nominal position, which on the one hand promotes
the release of thermal energy from combustion, and on the other
hand brings the injector closer to the combustion chamber.
[0086] The flow rate of vehicle fuel injected is adjusted so as to
obtain an exhaust temperature of 750.degree. C. at the start of the
test.
[0087] The injection advance was increased by 1.5.degree.
crankshaft relative to the nominal setting (changing from
+12.5.degree. to +14.degree. crankshaft) still with the aim of
increasing thermal stresses to which the injector nozzle is
subjected.
[0088] Finally, to increase the stresses to which the vehicle fuel
is subjected, the injection pressure was increased by 10 MPa
relative to the nominal pressure (i.e. changing from 140 MPa to 150
MPa) and the temperature is set at 65.degree. C. at the inlet of
the high-pressure pump.
[0089] The technology used for the injectors requires a high fuel
return, which promotes degradation of the vehicle fuel since it can
be subjected to several cycles in the high-pressure pump and the
high-pressure chamber before being injected into the combustion
chamber.
[0090] A variant of the method for testing the clean-up effect
(i.e. cleaning of type 1 and/or type 2 deposits) has also been
developed. It is based on the preceding method but is separated
into two 20 hour periods:
[0091] For the first 20 hours a higher-grade gas oil B7 is used
(containing detergent of the PIBSI type and an acid product) known
for its tendency to cause lacquering. After 20 hours, two of the
four injectors are dismantled and assessed in order to verify the
quantity of deposits present and then replaced by two new
injectors.
[0092] For the last 20 hours of the test, the product to be
assessed is used. At the end of the test (40 hours in total), the
injectors are dismantled and assessed.
[0093] At the end of the test, three sets of two injectors are
available:
[0094] Set 1: 2 injectors having undergone 20 hours of higher-grade
vehicle fuel known for its tendency to cause lacquering.
[0095] Set 2: 2 injectors having undergone 20 hours of higher-grade
vehicle fuel known for its tendency to cause lacquering+20 hours of
product to be assessed.
[0096] Set 3: 2 injectors having undergone 20 hours of product to
be assessed.
[0097] Expression of the Results:
[0098] In order to ensure the validity of the result, various
parameters are monitored during the test: power, torque and fuel
consumption indicate whether the injector is fouled or whether its
operation has deteriorated through formation of deposits, since the
operating point is the same throughout the test. The characteristic
temperatures of the various fluids (cooling liquid, vehicle fuel,
oil) allow the validity of the tests to be monitored. The vehicle
fuel is adjusted to 65.degree. C. at the pump inlet, and the
cooling liquid is adjusted to 90.degree. C. at the engine
outlet.
[0099] The smoke values allow the combustion timing to be monitored
at the start of the test (target value 3FSN) and ensure that it is
properly repeatable from one test to the next. The injectors are
dismantled at the end of the test in order to inspect and assess
the deposits formed along the needles. The procedure adopted for
assessing the needles is as follows:
[0100] The scale of scores varies from -2.5 (for a heavy deposit)
to 10 (for a new needle without any deposit). The final score is a
weighted average of the scores over all the assessed surfaces of
the needle, i.e. the conical part and the body or cylindrical part
of the needle.
[0101] Thus the cylindrical zone (directly following the conical
part) represents 68% of the overall assessment of the needle and
the conical zone represents 32% of the overall assessment of the
needle. In order to facilitate the assessment, each of these two
zones is divided into 4. In FIG. 4, the percentages shown
correspond to one quarter of the surface area of the needles: the
overall surface area weighting is therefore 17.times.4=68%. A
product performance threshold was determined with respect to this
assessment procedure: Result <4=Unsatisfactory, result
>4=Satisfactory.
[0102] The following examples illustrate the invention without
limiting it.
Example 1
Measurements of Lacquering Resistance
[0103] According to the procedure for measuring the lacquering
resistance described above, the performance is assessed of several
packets of additives introduced into a gas oil matrix
representative of the French market (B7=gas oil produced in France
containing 7% FAME (fatty acid methyl ester) and complying with EN
590). Details of each vehicle fuel composition tested, as well as
the results obtained, are shown in Table 1.
[0104] The quantities shown in Table 1 are quantities by mass
(m/m).
TABLE-US-00001 TABLE 1 Test No. A B C D E F Vehicle fuel B7 B7 B7
B7 B7 B7 PIBSI type diesel detergent -- 330 170 170 170 330 ppm ppm
ppm ppm ppm Fatty acid mixture, mainly -- 200 -- -- -- -- oleic
acid with an acid ppm number of 180 mg of KOH/g Sorbitan monooleate
-- -- 200 -- -- 100 ppm ppm Pentaerythritol mono- + di- -- -- --
200 -- -- oleate ppm Type 1 deposits score 8.7 -1 7.2 4.1 7.2 5.2
Type 2 deposits score 7.1 -1 6.9 6.7 6.0 6.2 Overall score 8.2 -1
7.0 5.0 6.4 5.9
[0105] These tests clearly demonstrate the effectiveness of the
products of the invention in preventing and limiting the formation
of varnish or soap type deposits (keep-clean action), since the
needle assessments results at the end of the tests are much better
than the assessment result obtained when the vehicle fuel contains
only a PIBSI capable of forming soaps on the injector needles.
Example 2
Measurements of Lacquering Resistance
[0106] According to the procedure for measuring the lacquering
resistance in its clean-up version described above, the performance
is assessed of several packets of additives introduced into a gas
oil matrix representative of the French market (B7=gas oil produced
in France containing 7% FAME (fatty acid methyl ester) and
complying with EN 590). Details of each vehicle fuel composition
tested, as well as the results obtained, are shown in Table 2. Note
tests G, G' and G'' correspond to the same test, with G
corresponding to the result for the set of injectors 1, G'
corresponding to the result for the set of injectors 2 and G''
corresponding to the result for the set of injectors 3.
[0107] The quantities shown in Table 2 are quantities by mass
(m/m)
TABLE-US-00002 TABLE 2 Test No. G G' G'' Vehicle fuel B7 B7 B7
PIBSI type diesel detergent 330 ppm 330 then 170 ppm 170 ppm Fatty
acid mixture, mainly oleic 200 ppm 200 then -- acid with an acid
number of 180 mg 0 ppm of KOH/g Sorbitan monooleate -- 0 then 200
ppm 200 ppm Type 1 deposits score 2.6 3.7 6.2 Type 2 deposits score
1.4 3.7 6.5 Overall score 1.8 3.7 6.4
[0108] These tests demonstrate the curative effectiveness (clean-up
action) of the products of the invention i.e. in removing the
varnish or soap type deposits already formed on the needles since
the assessment of the set of injectors G' is better than that of
the set of injectors G (significant cleaning of the needle has been
started), and also confirms their preventive effectiveness
(keep-clean action) since the assessment of the set of injectors
G'' is much higher.
* * * * *