U.S. patent application number 11/314590 was filed with the patent office on 2006-07-20 for fuels for compression-ignition engines.
Invention is credited to Christopher William Clayton, Mary Ann Dahlstrom, George Robert Lee, Richard John Price, Susan Jane Smith, Nigel Peter Tait, Jessica F. Wallington.
Application Number | 20060156620 11/314590 |
Document ID | / |
Family ID | 36682369 |
Filed Date | 2006-07-20 |
United States Patent
Application |
20060156620 |
Kind Code |
A1 |
Clayton; Christopher William ;
et al. |
July 20, 2006 |
Fuels for compression-ignition engines
Abstract
A fuel composition containing a major amount of a fuel suitable
for use in a compression-ignition engine, which fuel contains one
or more hydrocarbon components boiling within the diesel boiling
range, at least one of which hydrocarbon components has been
treated with a metal adsorbing or absorbing material in a different
physical phase from the hydrocarbon component(s), preferably to
reduce the level of at least one metal, more preferably the level
of at least one heavier metal, most preferably the level of zinc,
in said at least one hydrocarbon component, said treatment
including physical separation of the hydrocarbon component from the
metal adsorbing or absorbing phase, is used to operate a
compression-ignition engine, and/or a vehicle which is driven by a
compression-ignition engine, for the purpose of reducing subsequent
formation of deposits, preferably combustion related deposits,
during engine operation in the compression-ignition engine into
which the fuel composition is introduced and/or of removing from
the engine previously incurred deposits.
Inventors: |
Clayton; Christopher William;
(Chester, GB) ; Dahlstrom; Mary Ann; (Katy,
TX) ; Lee; George Robert; (Chester, GB) ;
Price; Richard John; (Chester, GB) ; Smith; Susan
Jane; (Chester, GB) ; Tait; Nigel Peter;
(Chester, GB) ; Wallington; Jessica F.; (Chester,
GB) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
US
|
Family ID: |
36682369 |
Appl. No.: |
11/314590 |
Filed: |
December 21, 2005 |
Current U.S.
Class: |
44/457 ;
123/294 |
Current CPC
Class: |
C10G 21/00 20130101;
C10L 1/08 20130101; C10G 2400/04 20130101 |
Class at
Publication: |
044/457 ;
123/294 |
International
Class: |
C10L 1/12 20060101
C10L001/12 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 23, 2004 |
EP |
04258093.6 |
Apr 12, 2005 |
EP |
05252268.7 |
Claims
1. A method of preparing a fuel composition comprising: (a)
providing a major amount of a fuel suitable for use in a
compression-ignition engine, which fuel comprises one or more
hydrocarbon components boiling within the diesel boiling range; (b)
treating at least one hydrocarbon component with a metal adsorbing
or absorbing material which is in a different physical phase from
the hydrocarbon component, thereby reducing the level of at least
one metal in said at least one hydrocarbon component; and (c)
physically separating the thus-treated hydrocarbon component from
the metal adsorbing or absorbing material.
2. The method of claim 1 wherein the metal adsorbing or absorbing
material is selected from the group consisting of fibrous clay
minerals, diatomaceous earths, graphite, charcoal, polymeric
adsorbents or absorbents, ion-exchange resins, and complexing or
chelating agents.
3. A method of operating a compression-ignition engine, and/or a
vehicle which is driven by a compression-ignition engine, said
compression-ignition engine having a combustion chamber, which
method comprising introducing into the combustion chamber a fuel
composition comprising a major amount of a fuel suitable for use in
a compression-ignition engine, said fuel comprising one or more
hydrocarbon components boiling within the diesel boiling range, at
least one of which hydrocarbon components has been treated with a
metal adsorbing or absorbing material effective to reduce the level
of at least one metal in said at least one hydrocarbon component,
said metal adsorbing or absorbing material being in a different
physical phase from the hydrocarbon component(s), said treatment
including physical separation of the hydrocarbon component from the
metal adsorbing or absorbing material, thereby reducing subsequent
formation of deposits during engine operation in the
compression-ignition engine and/or of removing from the engine
previously incurred deposits.
4. A method of reducing subsequent formation of deposits during
engine operation during engine operation in a compression-ignition
engine into which a fuel composition is introduced and/or of
removing from the engine previously incurred deposits, which method
comprising: providing into the combustion chambers of such engine a
fuel composition comprising a major amount of a fuel suitable for
use in a compression-ignition engine, said fuel comprising one or
more hydrocarbon components boiling within the diesel boiling
range, at least one of which hydrocarbon components has been
treated with a metal adsorbing or absorbing material effective to
reduce the level of at least one metal in said at least one
hydrocarbon component, said metal adsorbing or absorbing material
being in a different physical phase from the hydrocarbon
component(s), said treatment including physical separation of the
hydrocarbon component from the metal adsorbing or absorbing
material.
5. The method of claim 4 wherein reducing subsequent formation of
deposits in the compression-ignition engine and/or removing from
the engine previously incurred deposits has the effect of reducing
any power loss in the engine or improving the power generated by
the engine.
6. The method of claim 4 wherein the metal adsorbing or absorbing
material is selected from the group consisting of fibrous clay
minerals, diatomaceous earths, graphite and charcoal.
7. The method of claim 4 wherein the metal adsorbing or absorbing
material is selected from polymeric adsorbents or absorbents and
ion-exchange resins.
8. The method of claim 4 wherein the metal adsorbing or absorbing
material is selected from complexing or chelating agents.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the use of certain fuels in
the operation of compression-ignition engines.
BACKGROUND OF THE INVENTION
[0002] Diesel fuels can contain a number of trace metals. The
content of such metals depends on a number of factors, including
the source(s) of crude oil from which the fuel is derived, the
types of refinery processes employed, and the handling, storage and
distribution history of the fuel.
[0003] U.S. Pat. No.2,090,007, U.S. Pat. No. 2,338,142 or
GB-A-614636 describe treatment of hydrocarbons by passing them
through filtering or adsorbing material such as Fuller's Earth or
charcoal.
DETAILED DESCRIPTION OF THE INVENTION
[0004] GB-A-437023 describes a process for refining cracked
hydrocarbons of substantially gasoline boiling range by the
treatment with a solid active adsorbent such as Fuller's Earth,
clay or other suitable adsorptive catalysts, under conditions of
elevated temperature and superatmospheric pressure adequate to
maintain said hydrocarbons in substantially liquid phase, which
comprises first removing from said hydrocarbons relatively unstable
low boiling constituents, namely dissolved gases, propane, part or
all of the butanes and their corresponding unsaturates, and
reducing the vapour pressure of said hydrocarbons by submitting
them to a stabilising fractionation and thereupon subjecting the
stabilised hydrocarbons, whilst still hot, to said refining
treatment.
[0005] U.S. Pat. No. 3,529,944 describes a method for clarifying
and stabilising hydrocarbon liquids which are subject to oxidative
deterioration, particularly jet fuels, which includes adding to the
fuel a material which accelerates the oxidative deterioration of
the fuel, such as a polyphenyl substituted lower alkane or lower
alkylene, an alkanol ester of citric acid or acetoxy ethyl
monobutylether; passing the hydrocarbon liquid through a solid,
particulate, adsorbent media to remove microimpurities and the
products of oxidative deterioration; and thereafter adding
additional amounts of a stabilising material to stabilise the
hydrocarbon liquid against further oxidative deterioration.
Suitable adsorbent materials (column 5, lines 22 to 25) include
various types of natural or synthetic clays, either treated or
untreated, Fuller's Earth, attapulgite, silica gel and adsorbent
catalysts. In the examples, jet fuels are treated by filtration
through attapulgite clay.
[0006] In U.S. Pat. No. 4,225,319, in order to suppress carburettor
deposit formation, adsorbent-treated cat cracked gasoline is
blended into a fuel composition for use in an internal combustion
engine. In column 2, lines 57 to 62, it is stated that adsorbents
which are useful "for treating the cat cracked gasoline include
many of the well known adsorbents such as silica, alumina,
silica-alumina, charcoal, carbon black, magnesium silicate,
aluminium silicate, zeolites, clay, fuller's earth, magnesia, and
the like". In the examples, the adsorbent used is silica-gel.
[0007] U.S. Pat. No. 5,951,851 relates to a process for removing
elemental sulfur from fluids, particularly fuels such as gasoline,
jet fuel, diesel, kerosene and fuel additives such as ethers. The
process involves contacting the sulfur contaminated fluid with
layered double hydroxide (or hydrotalcite) Mg.sub.2AlNO.sub.3;
mH.sub.2O or Mg.sub.3AlNO.sub.3; mH.sub.2O, where m is the number
of waters of hydration. In Example 1, it can be seen that
Attapulgus clay, molecular sieve 5 .ANG., silica gel, alumina,
bayerite, tetraphenylphosphonium-montmorillonite, Kao-EG.9.4 .ANG.,
Kao-tetraethylene glycol, Al.sub.13 pillared montmorillonite,
tetramethylammonium-montmorillonite, palygorskite-PF1-s, Kaolinite
KGa-1, Kao-cellosolve and Iron (III) montmorillonite are
ineffective in removing elemental sulfur, whilst the hydrotalcites
Al.sub.2LiCl, Mg.sub.2AlNO.sub.3, Mg.sub.2FeNO.sub.3,
Mg.sub.3FeNO.sub.3 and Mg.sub.3AlNO.sub.3 are particularly
effective in removing elemental sulfur.
[0008] The New Encylopaedia Britannica, Macropaedia, Volume 4,
15.sup.th Edition, 1984, ISBN 0-85229-413-1, Pages 700 to 706
classifies clay minerals on the basis of variations of atomic
structure and chemical composition into 9 groups, viz (1)
allophane, (2) kaolinite, (3) halloysite, (4) smectite, (5) illite,
(6) chlorite, (7) vermiculite, (8) sepiolite, attapulgite and
palygorskite and (9) mixed layer clay minerals.
[0009] Group (8), sepiolite, attapulgite and palygorskite, are
described as fibrous clay minerals, and these have, as an important
structural element, the amphibole double silica chain which is
orientated parallel to the c axis.
[0010] Compression-ignition (diesel) engines running on diesel
fuels can suffer from the formation of deposits during engine
operation in their fuel injection systems, in particular in the
injector nozzles. This fouling can impair engine performance. To
reduce fouling, a detergent-containing additive may be included in
the fuel.
[0011] However, when at least one hydrocarbon component of a diesel
fuel composition has been treated with a metal adsorbing or
absorbing material in a different physical phase from the
hydrocarbon component(s), which material may for example be in
liquid form which is immiscible (including having minimal or low
solubility) with the hydrocarbon component, or a solid, preferably
a solid, to reduce the levels of trace metal contaminants, more
preferably the level of heavier metals, most preferably the level
of zinc, in said component(s), the fuel composition can itself
contribute to a reduction in, and/or reversal of, injector fouling.
Said treatment includes physical separation of the hydrocarbon
component and the metal adsorbing or absorbing phase, for example
by one or more of decanting of immiscible liquid, filtration,
vortexing, centrifuging and gravity separation. A fuel composition
which has been so treated can therefore be used to help maintain
engine cleanliness and/or improve such cleanliness and/or reduce
the rate of deterioration of such cleanliness.
[0012] For the purpose of this disclosure, "heavier metals" are
defined as metals with atomic numbers of 20 or greater.
[0013] In accordance with one embodiment of the present invention
there is provided a method of preparing a fuel composition
comprising: (a) providing a major amount of a fuel suitable for use
in a compression-ignition engine, which fuel comprises one or more
hydrocarbon components boiling within the diesel boiling range; (b)
treating at least one hydrocarbon component with a metal adsorbing
or absorbing material which is in a different physical phase from
the hydrocarbon component, thereby reducing the level of at least
one metal in said at least one hydrocarbon component; and (c)
physically separating the thus-treated hydrocarbon component from
the metal adsorbing or absorbing material.
[0014] In accordance with one embodiment of the present invention
there is provided use of a fuel composition comprising a major
amount of a fuel suitable for use in a compression-ignition engine,
which fuel comprises one or more hydrocarbon components boiling
within the diesel boiling range, at least one of which hydrocarbon
components has been treated with a metal adsorbing or absorbing
material in a different physical phase from the hydrocarbon
components(s), preferably to reduce the level of at least one
metal, more preferably the level of at least one heavier metal,
most preferably the level of zinc, in said at least one hydrocarbon
component, said treatment including physical separation of the
hydrocarbon component from the metal adsorbing or absorbing phase,
for the purpose of reducing subsequent formation of deposits,
preferably combustion related deposits, during engine operation in
a compression-ignition engine into which the fuel composition is
introduced and/or of removing from the engine previously incurred
deposits.
[0015] In accordance with another embodiment of the present
invention there is also provided a method of operating a
compression-ignition engine, and/or a vehicle which is driven by a
compression-ignition engine, said compression-ignition engine
having a combustion chamber, which method comprising introducing
into a combustion chamber of the engine a fuel composition
comprising a major amount of a fuel suitable for use in a
compression-ignition engine, which fuel comprises one or more
hydrocarbon components boiling within the diesel boiling range, at
least one of which hydrocarbon components has been treated with a
metal adsorbing or absorbing material in a different physical phase
from the hydrocarbon component(s), preferably to reduce the level
of at least one metal, more preferably the level of at least one
heavier metal, most preferably the level of zinc, in said at least
one hydrocarbon component, said treatment including physical
separation of the hydrocarbon component from the metal adsorbing or
absorbing phase, for the purpose of reducing subsequent formation
of deposits, preferably combustion related deposits, during engine
operation in the compression-ignition engine and/or of removing
from the engine previously incurred deposits.
[0016] In accordance with another embodiment of the present
invention there is also provided a method of operating a
compression-ignition engine, and/or a vehicle which is driven by a
compression-ignition engine, said compression-ignition engine
having a combustion chamber, which method comprising introducing
into the combustion chamber a fuel composition comprising a major
amount of a fuel suitable for use in a compression-ignition engine,
said fuel comprising one or more hydrocarbon components boiling
within the diesel boiling range, at least one of which hydrocarbon
components has been treated with a metal adsorbing or absorbing
material effective to reduce the level of at least one metal in
said at least one hydrocarbon component, said metal adsorbing or
absorbing material being in a different physical phase from the
hydrocarbon component(s), said treatment including physical
separation of the hydrocarbon component from the metal adsorbing or
absorbing material, thereby reducing subsequent formation of
deposits during engine operation in the compression-ignition engine
and/or of removing from the engine previously incurred
deposits.
[0017] In accordance with another embodiment of the present
invention there is further provided a method of reducing subsequent
formation of deposits, preferably combustion related deposits,
during engine operation in a compression-ignition engine into which
a fuel composition is introduced and/or of removing from the engine
previously incurred deposits, which method comprises bringing into
the combustion chambers of such engine a fuel composition
comprising a major amount of a fuel suitable for use in a
compression-ignition engine, which fuel comprises one or more
hydrocarbon components boiling within the diesel boiling range, at
least one of which hydrocarbon components has been treated with a
metal adsorbing or absorbing material in a different physical phase
from the hydrocarbon component(s), preferably to reduce the level
of at least one metal, more preferably the level of at least one
heavier metal, most preferably the level of zinc, in said at least
one hydrocarbon component, said treatment including physical
separation of the hydrocarbon component from the metal adsorbing or
absorbing phase.
[0018] In accordance with another embodiment of the present
invention there is further provided a method of reducing subsequent
formation of deposits, preferably combustion related deposits,
during engine operation in a compression-ignition engine into which
a fuel composition is introduced and/or of removing from the engine
previously incurred deposits, which comprises replacing a fuel
composition by a fuel composition comprising a major amount of a
fuel suitable for use in a compression-ignition engine, which fuel
comprises one or more hydrocarbon components boiling within the
diesel boiling range, at least one of which hydrocarbon components
has been treated with a metal adsorbing or absorbing material in a
different physical phase from the hydrocarbon component(s),
preferably to reduce the level of at least one metal, more
preferably the level of at least one heavier metal, most preferably
the level of zinc, in said at least one hydrocarbon component, said
treatment including physical separation of the hydrocarbon
component from the metal adsorbing or absorbing phase.
[0019] Most preferably, reducing subsequent formation of deposits
in the compression-ignition engine and/or removing from the engine
previously incurred deposits has the effect of reducing any power
loss in the engine or improving the power generated by the
engine.
[0020] Preferably, the metal adsorbing or absorbing material is
selected from fibrous clay minerals, diatomaceous earths, graphite,
charcoal, polymeric adsorbents or absorbents, ion-exchange resins,
and complexing or chelating agents, which materials may be in
liquid form which is immiscible (including having minimal or low
solubility) with the hydrocarbon component, or solids, more
preferably solids. Said complexing or chelating agents preferably
comprise molecules having one or more functional groups acting as a
ligand or forming a complex or being otherwise
metal-attracting.
[0021] The fibrous clay mineral of the sepiolite, attapulgite and
palygorskite group must at least contain at least one mineral of
the sepiolite, attapulgite and palygorskite groups. The term
"Fuller's Earth" is used in published literature on clays in a
number of different ways, but in the context of the present
invention "Fuller's Earth" comprises at least one fibrous clay
mineral of the sepiolite, attapulgite and palygorskite groups. One
type of Fuller's Earth may comprise a mixture of montmorillonite
and palygorskite.
[0022] Preferably the fibrous clay mineral is sepiolite,
attapulgite, or Fuller's Earth.
[0023] Preferably, the polymeric material is selected from
polyolefins such as polyacrylate or polystyrene, polyester,
polyether, polyamide, polyamine and polysulphone materials, for
example AMBERLITE XAD-4, AMBERLITE XAD-7 and AMBERLITE XAD-16
non-ionic polymeric adsorbents and polyethylene imine on silica gel
(available ex. Aldrich), said polymeric materials being in solid
form, or bound to a solid, or in liquid or suspension or dissolved
form which is immiscible (including having minimal or low
miscibility) with the hydrocarbon component.
[0024] Preferably, examples of said diatomaceous earths are DAMOLIN
MOLER (available ex. Damolin) and HYFLO SUPER CEL (available ex.
Aldrich).
[0025] Preferably, the complexing or chelating agents are selected
from nitrogen materials such as amines, amides, polyamines, cyclic
polyamines including but not limited to porphyrins, derivatives of
N,N'-disalicylidene-propanediamine, sulfur materials such as
sulphides, sulphones, sulphoxides, sulphonates, thiols, anionic
materials such as carboxylates, oxygen species such as alcohols,
ketones, phenols and ethers, including polyethers and cyclic
polyethers (crown ethers), and species containing both nitrogen and
oxygen such as cryptands and oxazoles and derivatives thereof, said
complexing or chelating agents being in solid form, or bound to a
solid, or in liquid or suspension or dissolved form which is
immiscible (including having minimal or low miscibility) with the
hydrocarbon component.
[0026] Preferably, the ion-exchange resins are selected from
mineral species, such as silica gels, and polymers with functional
groups such as sulphonate and carboxylate, such as some of the
products available from Aldrich under the trade names AMBERLITE,
AMBERLYST, DOWEX and SEPHADEX.
[0027] Preferably, a blend of at least two of said hydrocarbon
components has been treated with the metal adsorbing or absorbing
material.
[0028] In this specification, the terms "reduce", "reducing" and
"reduction" mean as compared to prior to the treatment with the
metal adsorbing or absorbing material or as compared to when using
a diesel fuel composition components of which have not been
subjected to said treatment, as appropriate. In the context of the
present invention, "reducing" includes complete prevention and
"removing" embraces both complete and partial removal.
[0029] The processes of adsorption or absorption of trace elements
on to clay are not completely understood. One possibility is that
the metals bond to the surface in the same way that they bond to
ligands. Ligands are molecules or ions that function as electron
donors and attract metal atoms or ions.
[0030] The fuel compositions to which the present invention relates
include diesel fuel compositions for use in automotive compression
ignition engines, as well as in other types of engine such as for
example marine, railroad and stationary engines, and industrial gas
oils for use in heating applications (e.g. boilers), provided that
these non-automotive fuels do not contain residual (non-distilled)
components.
[0031] The base fuel may itself contain a mixture of two or more
different diesel fuel components, and/or be additivated as
described below.
[0032] Such diesel fuel compositions will contain one or more base
fuels which may typically comprise liquid hydrocarbon middle
distillate gas oil(s), for instance petroleum derived gas oils.
Such fuel compositions will typically have boiling points within
the usual diesel range of 150 to 400.degree. C., depending on grade
and use. They will typically have a density from 750 to 1000
kg/m.sup.3, preferably for automotive uses from 780 to 860
kg/m.sup.3, at 15.degree. C. (e.g. ASTM D4502 or IP 365) and a
cetane number (ASTM D613) of from 35 to 120, more preferably from
40 to 85. They will typically have an initial boiling point in the
range 150 to 230.degree. C. and a final boiling point in the range
290 to 400.degree. C. Their kinematic viscosity at 40.degree. C.
(ASTM D445) might suitably be from 1.5 to 6 mm.sup.2/s.
[0033] Such industrial gas oils will contain a base fuel which may
comprise fuel fractions such as the kerosene or gas oil fractions
obtained in traditional refinery processes, which upgrade crude
petroleum feedstock to useful products. Preferably such fractions
contain components having carbon numbers in the range 5-40, more
preferably 5-31, yet more preferably 6-25, most preferably 9-25,
and such fractions have a density at 15.degree. C. of 650-1000
kg/m.sup.3, a kinematic viscosity at 20.degree. C. of 1-80
mm.sup.2/s, and a boiling range of 150-400.degree. C.
[0034] Optionally, non-mineral oil based fuels, such as
Fischer-Tropsch derived fuels, biomass-derived materials, biofuel
components such as fatty acid methyl esters, or shale oils, may
also form or be present in the fuel composition. Such
Fischer-Tropsch fuels may for example be derived from natural gas,
natural gas liquids, petroleum or shale oil, petroleum or shale oil
processing residues, coal or biomass.
[0035] The amount of Fischer-Tropsch derived fuel used in a diesel
fuel composition may be from 0.5 to 100% v of the overall diesel
fuel composition, preferably from 5 to 75% v. It may be desirable
for the composition to contain 10% v or greater, more preferably
20% v or greater, still more preferably 30% v or greater, of the
Fischer-Tropsch derived fuel. It is particularly preferred for the
composition to contain 30 to 75% v, and particularly 30 or 70% v,
of the Fischer-Tropsch derived fuel. The balance of the fuel
composition is made up of one or more other fuels.
[0036] An industrial gas oil composition will preferably comprise
more than 50 wt %, more preferably more than 70 wt %, of a
Fischer-Tropsch derived fuel component.
[0037] Such a Fischer-Tropsch derived fuel component is any
fraction of the middle distillate fuel range, which can be isolated
from the (hydrocracked) Fischer-Tropsch synthesis product. Typical
fractions will boil in the naphtha, kerosene or gas oil range.
Preferably, a Fischer-Tropsch product boiling in the kerosene or
gas oil range is used because these products are easier to handle
in for example domestic environments. Such products will suitably
comprise a fraction larger than 90 wt % which boils between 160 and
400.degree. C., preferably to about 370.degree. C. Examples of
Fischer-Tropsch derived kerosene and gas oils are described in
EP-A-0583836, WO-A-97/14768, WO-A-97/14769, WO-A-00/11116,
WO-A-00/11117, WO-A-01/83406, WO-A-01/83648, WO-A-01/83647,
WO-A-01/83641, WO-A-00/20535, WO-A-00/20534, EP-A-1101813, U.S.
Pat. No. 5,766,274, U.S. Pat. No. 5,378,348, U.S. Pat. No.
5,888,376 and U.S. Pat. No. 6,204,426.
[0038] The Fischer-Tropsch product will suitably contain more than
80 wt % and more suitably more than 95 wt % iso and normal
paraffins and less than 1 wt % aromatics, the balance being
naphthenics compounds. The content of sulfur and nitrogen will be
very low and normally below the detection limits for such
compounds. For this reason the sulfur content of a fuel composition
containing a Fischer-Tropsch product may be very low.
[0039] The fuel composition preferably contains no more than 5000
ppmw sulfur, more preferably no more than 500 ppmw, or no more than
350 ppmw, or no more than 150 ppmw, or no more than 100 ppmw, or no
more than 50 ppmw, or most preferably no more than 10 ppmw
sulfur.
[0040] The base fuel may itself be additivated
(additive-containing) or unadditivated (additive-free). If
additivated, e.g. at the refinery, it will contain minor amounts of
one or more additives selected for example from anti-static agents,
pipeline drag reducers, flow improvers (e.g. ethylene/vinyl acetate
copolymers or acrylate/maleic anhydride copolymers), lubricity
additives, antioxidants and wax anti-settling agents.
[0041] Detergent-containing diesel fuel additives are known and
commercially available. Such additives may be added to diesel fuels
at levels intended to reduce, remove, or slow the build up of
engine deposits.
[0042] Examples of detergents suitable for use in fuel additives
for the present purpose include polyolefin substituted succinimides
or succinamides of polyamines, for instance polyisobutylene
succinimides or polyisobutylene amine succinamides, aliphatic
amines, Mannich bases or amines and polyolefin (e.g.
polyisobutylene) maleic anhydrides. Succinimide dispersant
additives are described for example in GB-A-960493, EP-A-0147240,
EP-A-0482253, EP-A-0613938, EP-A-0557516 and WO-A-98/42808.
Particularly preferred are polyolefin substituted succinimides such
as polyisobutylene succinimides.
[0043] The additive may contain other components in addition to the
detergent. Examples are lubricity enhancers; dehazer compositions,
e.g. those containing alkoxylated phenol formaldehyde polymers;
anti-foaming agents (e.g. polyether-modified polysiloxanes);
ignition improvers (cetane improvers) (e.g. 2-ethylhexyl nitrate
(EHN), cyclohexyl nitrate, di-tert-butyl peroxide and those
disclosed in U.S. Pat. No. 4,208,190 at column 2, line 27 to column
3, line 21); anti-rust agents (e.g. a propane-1,2-diol semi-ester
of tetrapropenyl succinic acid, or polyhydric alcohol esters of a
succinic acid derivative, the succinic acid derivative having on at
least one of its alpha-carbon atoms an unsubstituted or substituted
aliphatic hydrocarbon group containing from 20 to 500 carbon atoms,
e.g. the pentaerythritol diester of polyisobutylene-substituted
succinic acid); corrosion inhibitors; reodorants; anti-wear
additives; anti-oxidants (e.g. phenolics such as
2,6-di-tert-butylphenol, or phenylenediamines such as
N,N'-di-sec-butyl-p-phenylenediamine); metal deactivators; and
combustion improvers.
[0044] It is particularly preferred that the additive include a
lubricity enhancer, especially when the fuel composition has a low
(e.g. 500 ppmw or less) sulfur content. In the additivated fuel
composition, the lubricity enhancer is conveniently present at a
concentration less than 1000 ppmw, preferably between 5 and 1000
ppmw. Suitable commercially available lubricity enhancers include
ester- and acid-based additives. Other lubricity enhancers are
described in the patent literature, in particular in connection
with their use in low sulfur content diesel fuels, for example in:
[0045] the paper by Danping Wei and H. A. Spikes, "The Lubricity of
Diesel Fuels", Wear, III (1986) 217-235; [0046] WO-A-95/33805--cold
flow improvers to enhance lubricity of low sulfur fuels; [0047]
WO-A-94/17160--certain esters of a carboxylic acid and an alcohol
wherein the acid has from 2 to 50 carbon atoms and the alcohol has
1 or more carbon atoms, particularly glycerol monooleate and
di-isodecyl adipate, as fuel additives for wear reduction in a
diesel engine injection system; [0048] U.S. Pat. No.
5,490,864--certain dithiophosphoric diester-dialcohols as anti-wear
lubricity additives for low sulfur diesel fuels; and [0049]
WO-A-98/01516--certain alkyl aromatic compounds having at least one
carboxyl group attached to their aromatic nuclei, to confer
anti-wear lubricity effects particularly in low sulfur diesel
fuels.
[0050] It is also preferred that the additive contain an
anti-foaming agent, more preferably in combination with an
anti-rust agent and/or a corrosion inhibitor and/or a lubricity
additive.
[0051] Unless otherwise stated, the (active matter) concentration
of each such additional component in the additivated fuel
composition is preferably up to 10000 ppmw, more preferably in the
range from 0.1 to 1000 ppmw, advantageously from 0.1 to 300 ppmw,
such as from 0.1 to 150 ppmw. The (active matter) concentration of
any dehazer in the fuel composition will preferably be in the range
from 0.1 to 20 ppmw, more preferably from 1 to 15 ppmw, still more
preferably from 1 to 10 ppmw, advantageously from 1 to 5 ppmw. The
(active matter) concentration of any ignition improver present will
preferably be 2600 ppmw or less, more preferably 2000 ppmw or less,
conveniently from 300 to 1500 ppmw.
[0052] If desired, the additive components, as listed above, may be
co-mixed, preferably together with suitable diluent(s), in an
additive concentrate, and the additive concentrate may be dispersed
into the fuel, in suitable quantity to result in a composition of
the present invention.
[0053] In the case of a diesel fuel composition, for example, the
additive will typically contain a detergent, optionally together
with other components as described above, and a diesel
fuel-compatible diluent, which may be a carrier oil (e.g. a mineral
oil), a polyether, which may be capped or uncapped, a non-polar
solvent such as toluene, xylene, white spirits and those sold by
member companies of the Royal Dutch/Shell Group under the trade
mark "SHELLSOL".
[0054] The total content of the additives may be suitably between 0
and 10000 ppmw and preferably below 5000 ppmw.
[0055] In this specification, amounts (concentrations, % v, ppmw,
wt %) of components are of active matter, i.e. exclusive of
volatile solvents/diluent materials.
[0056] The treatment according to the present invention may be
applied before or after any additives are blended into the fuel
composition, as appropriate.
[0057] The level of formation of deposits during engine operation
in a diesel engine may be measured in its fuel injection system,
with reference to the degree of fouling of the injector nozzles.
Degree of nozzle fouling may be assessed in a number of ways, for
instance visually, by measuring the mass of deposits in a fouled
nozzle or by measuring the fluid flow (for instance, fuel flow or
more preferably air flow) properties of the fouled nozzle relative
to those of the clean nozzle.
[0058] An appropriate test might for example determine the degree
of nozzle fouling (conveniently in the form of a percentage
injector fouling index) in a suitable diesel engine, for instance
based on the change in air flow rate through one or more of the
nozzles as a result of using the fuel composition. Conveniently the
results are averaged over all of the injector nozzles of the
engine.
[0059] The present invention is particularly applicable where the
fuel composition is used or intended to be used in a direct
injection diesel engine, for example of the rotary pump, in-line
pump, unit pump, electronic unit injector or common rail type, in
an indirect injection diesel engine or in a homogeneous charge
compression ignition engine. The fuel composition may be suitable
for use in heavy and/or light duty diesel engines.
[0060] As mentioned above, it is also applicable where the fuel
composition is used in heating applications, for example boilers.
Such boilers include standard boilers, low temperature boilers and
condensing boilers, and are typically used for heating water for
commercial or domestic applications such as space heating and water
heating.
[0061] In the diesel fuel composition, hydrocarbons can be
supplemented by oxygenates such as esters known for use in diesel
fuel.
[0062] In the process of the present invention the treatment with
metal adsorbing or absorbing material is effected with the
hydrocarbons in the liquid phase, very conveniently at ambient
temperature. At ambient temperature, the treatment may very
conveniently be effected at atmospheric pressure.
[0063] Whilst when it is known that a particular hydrocarbon
refinery component or combination/components of a fuel composition
is at least predominantly responsible for the presence of metals to
be removed, that component or combination of components may be
treated with the metal adsorbing or absorbing material before
blending with at least the other hydrocarbon refinery component to
form the fuel composition, the fully pre-blended fuel composition
may also be treated.
[0064] The level of formation of deposits during engine operation
may for example be measured by assessing the degree of fouling of
the injector nozzles in the fuel injection system of the engine, as
described above.
[0065] If formation of deposits in the fuel injectors during
vehicle operation are to be measured, the test cycles involve
running the engine on the relevant fuel composition for a given
period of time and/or for a given number of miles. The tests may be
conducted on the engine alone or driving a vehicle--in the latter
case they may be conducted under simulated driving conditions (such
as using a chassis dynamometer) or involve regular road driving.
The tests may be conducted in "Keep-Clean" mode (i.e. by running
the engine on treated fuel, followed by examination of the engine)
or in "Clean-Up" mode (i.e. by running one test cycle on untreated
fuel to generate deposits, followed by running a second test cycle
on treated fuel). In the latter case, the engine running and/or
driving conditions should be the same or comparable for both the
first test cycle and the second test cycle.
[0066] By way of example, in "Clean-Up" tests the duration of the
"first test cycle" should be sufficient to cause a significant, and
at least detectable, build up of combustion related deposits. An
appropriate duration for the "second test cycle" is typically from
10 to 100%, preferably from 50 to 100%, most suitably 100%, of that
of the first test cycle. It may in cases be 80% or 75% or even 50%
or less of the duration of the "first test cycle". For assessing
reductions in (as opposed to removal of) combustion related
deposits, it may be up to 120% or 150% or even 200% of the duration
of the "first test cycle", although it could be even greater.
[0067] In any type of testing, the test may be conducted on only a
part of the engine (for example, the fuel injection system) or on a
simulated engine or engine part.
[0068] The present invention will now be further described by
reference to the following illustrative embodiments that are
provided for illustrative purposes and are not meant as limiting
the invention. Unless otherwise indicated, parts and percentages
are by weight, and temperatures are in degrees Celsius.
EXAMPLES
Example 1
[0069] The fuels referred to in Example 1 were as set out in
TABLE-US-00001 TABLE 1 Property Fuel A Fuel B Density @ 15.degree.
C. 835.7 835.5 (kg/m.sup.3) Cetane 52.7 53.3 Sulfur mg/kg 212 210
Distillation (.degree. C.) IBP 183.0 185.3 10% rec 208.5 210.5 20%
rec 221.5 222.8 30% rec 235.0 235.5 40% rec 248.5 249.1 50% rec
263.0 263.6 60% rec 277.5 278.2 70% rec 293.5 293.9 80% rec 311.5
310.6 90% rec 333.0 331.9 95% rec 350.0 348.3 FBP 361.0 361.1 HPLC
aromatics (% m/m) Mono 26.8 26.7 Di 4.5 4.2 Tri 0.7 0.5 Total 32
31.4
[0070] Fuel A was a market fuel from Hungary that is compliant with
EN590 and which was used without any further treatment. Fuel B was
Fuel A which had been treated by being passed through a clay column
as described below.
[0071] By comparing the characteristics of Fuels A and B set out in
Table 1 it can be seen that the physical properties (density and
cetane number) were essentially unchanged by the clay treatment. It
can also be seen that the aromatic (mono-, di- and tri-) content
and sulfur content were also essentially unchanged by said
treatment, as were the distillation characteristics.
Metals Content and Clay Filtration
[0072] The metal content of Fuel A was determined using the
following technique, ICP-MS (Inductively Coupled Plasma-Mass
Spectrometry). Said technique involves spraying the fuel containing
the metals into a spray chamber to form a fine spray. Here the
larger droplets are removed and 1 to 2% of the sample solution
enters into the inductively coupled plasma. The plasma is produced
in a quartz torch, via the interaction of an intense magnetic field
and flowing argon. The plasma discharge has a high temperature,
approximately 10000.degree. C. In ICP-MS the plasma is used to
generate positively charged ions. Once the ions are produced in the
plasma, they are directed into the mass spectrometer via the
interface region from where the positive ions are focused down a
quadruple mass spectrometer. The results (in ppbw) are set out in
Table 2 below.
[0073] A glass column of about 1 metre in height and diameter of
7.5 cm, having a tap at the bottom and a loose glass cap on top,
was fitted with a glass wool layer immediately above the tap and
was then loaded with 0.5 kg of dry clay, in powder form. The clay
filled the column to about 40 cm above the tap, and the glass wool
layer prevented clay from falling into the tap.
[0074] Fuel A at ambient temperature (20.degree. C.) was then
poured into the column, to a depth of 25 to 30 cm above the clay.
Flow rate was adjusted to 1 litre/hour, and the column was
regularly topped up with fuel. A total volume of 50 litres was
passed through the column. The first litre of permeate was
discarded, and subsequently 5 litre samples (Fuel B) were
collected. The 2nd, 4th, 6th, 8th and final samples (Fuel B) were
tested for metal content. The average values (in ppbw) were as set
out in Table 2 below: TABLE-US-00002 TABLE 2 Metal Fuel A Fuel B Ag
<50 <50 B <50 <50 Cr 14 <5 Cu <50 <50 Fe 84
<5 Mg 76 <5 Mn 8 <5 Mo <50 <50 Ni <50 <50 Pb
50 <40 Sn <50 <50 Ti <50 <50 Zn 1500 26 V <50
<50
[0075] It is to be noted that the levels of chromium (Cr), iron
(Fe), lead (Pb), magnesium (Mg), manganese (Mn) and zinc (Zn) were
all reduced after the clay treatment. The reduction in the level of
zinc was particularly marked.
[0076] The levels of metals could be further reduced by
optimisation of the operating conditions of the process, or by
passing the fuel through a second bed of solid, or by other
means.
[0077] The clay which was employed was Attapulgite, mesh size
30-60, ex. Wilfrid Smith Limited (manufactured by Millwhite). Other
suitable clays include Fuller's Earth, e.g. mesh size 30-60, ex.
Aldrich, and Sepiolite, e.g. grade 30-60, ex. Steetly Bentonite
& Absorbents Ltd.
Example 2
[0078] The fuels referred to in Example 2 were as set out in Table
3: TABLE-US-00003 TABLE 3 Property Fuel C Fuel D Fuel E Fuel F Fuel
G Density @ 15.degree. C. 0.8394 0.8391 0.8391 0.8394 0.8395
(g/cm.sup.3)
[0079] Fuel C was a 275 ppmw sulfur diesel fuel. Fuels D, E, F, and
G were Fuel C which had been treated by being passed through
DAMOLIN MOLER (diatomaceous earth ex. Damolin), AMBERLITE XAD-7
(polymeric adsorbent ex. Aldrich), polyethylene imine on silica gel
(ex. Aldrich), and AMBERLYST 15 (ion-exchange resin, ex. Aldrich),
respectively, as described below.
[0080] It can be seen that the density of Fuels C to G was
essentially unchanged.
Metals Content and Filtration
[0081] The metals content of Fuel C was determined using the
technique described in Example 1 with respect to Fuel A. The
results (in ppbw) are set out in Table 4 below.
[0082] Fuel C was then treated at ambient temperature (20.degree.
C.) with the metal adsorbing or absorbing materials DAMOLIN MOLER,
AMBERLITE XAD-7, polyethylene imine on silica gel, and AMBERLYST
15, to produce Fuels D to G respectively, as described below.
[0083] Fuel D was obtained when Fuel C was treated in a column
approximately 1 m high with a diameter of about 7.5 cm and a tap at
the bottom. Approximately 250 g of dry solid was loaded into the
column, on top of a layer of glass wool. The solid filled the
column to approximately 20 cm above the tap. The fuel was passed
once through the column with the first .about.100 ml being
discarded.
[0084] Fuels E, F, and G were obtained when Fuel C was treated in
columns about 50 cm high with a diameter of 2 cm and a tap at the
bottom. In each case, approximately 40 g of solid was loaded into
the column, on top of a layer of glass wool. The solid filled the
column to approximately 30 cm above the tap. The fuels were passed
once through the columns, with the first .about.100 ml being
discarded.
[0085] Fuels D to G were then tested for metals content. The
average values (in ppbw) were as set out in Table 4 below:
TABLE-US-00004 TABLE 4 Metal Fuel C Fuel D Fuel E Fuel F Fuel G Ag
<20 <20 <20 <20 <20 Al <100 <100 <100
<100 nd B <500 <500 <500 <500 nd Cr <20 <20
<20 <20 <5 Cu 275 <10 30 145 130 Fe 10 <5 <5
<5 <5 Mg <100 <100 <100 <100 <5 Mn <5 <5
<5 <5 <5 Mo <20 <20 <20 <20 <20 Ni <20
<20 <20 <20 nd Pb <100 <100 <100 <100 <50
Sn <50 <50 <50 <50 <50 Ti <20 <20 <20
<20 <20 V <50 <50 <50 <50 nd Zn 1740 <5 5 160
590 nd = not determined
[0086] It is to be noted that the levels of copper (Cu), iron (Fe)
and zinc (Zn) were reduced after the treatment with each of the
metal adsorbing or absorbing materials. The reduction in the level
of zinc was particularly marked.
[0087] The levels of metals in the fuel may be reduced further by
optimisation of the conditions of the process, or by passing the
fuel through a second process of contact with metal adsorbing or
absorbing material, or by alternative means. Further reductions in
metal level may be desirable to achieve the optimum reduction in
the formation of deposits during engine operation, preferably
combustion related deposits.
[0088] The degree of fouling of the injector nozzles in the fuel
injection system of an engine, caused by such deposits, can be
reduced by the treatment according to the present invention. This,
in turn, can reduce any power loss in the engine or improve the
power generated by the engine.
[0089] The reduction in the level of zinc was particularly
marked.
[0090] The levels of metals in the fuel may be reduced further by
optimisation of the conditions of the process, or by passing the
fuel through a second process of contact with metal adsorbing or
absorbing material, or by alternative means. Further reductions in
metal level may be desirable to achieve the optimum reduction in
the formation of deposits during engine operation, preferably
combustion related deposits.
[0091] The degree of fouling of the injector nozzles in the fuel
injection system of an engine, caused by such deposits, can be
reduced by the treatment according to the present invention. This
has been demonstrated by the tests described in Example 3.
Example 3
[0092] The fuels used in the tests described below included those
set out in Table 5: TABLE-US-00005 TABLE 5 Property Fuel H Fuel K
Density @ 15.degree. C. 841.8 841.8 (kg/m.sup.3) Sulfur mg/kg 7.1
7.2 Distillation (.degree. C.) IBP 167.5 169.2 10% rec 202.8 203.2
20% rec 221.5 221.8 30% rec 237.2 238.1 40% rec 250.9 251.8 50% rec
263.3 265.3 60% rec 276.6 276.9 70% rec 290.1 290.2 80% rec 305.7
305.7 90% rec 326.3 327.1 95% rec 342.8 344.6 FBP 352.6 352.5
[0093] Fuel H was a zero sulfur diesel fuel, which was doped with
copper, iron and zinc, using metallo-organic solutions of said
metals, to form a Fuel I. Fuel K was produced by passing Fuel I
through a clay column, using the technique as described above in
Example 1, to form a Fuel J, to which then were added 1 ppmw of an
anti-static additive ("STADIS 450", ex. Du Pont) and 400 ppmw of a
lubricity additive ("R655", ex. Infineum).
[0094] The density, sulfur level and distillation characteristics
of Fuel I were not measured as they would have been the same as
those of Fuel H, i.e. as they would have been essentially unchanged
by the above-mentioned doping with metals.
[0095] Similarly, the density, sulfur level and distillation
characteristics of Fuel J were not measured as they would have been
the same as those of Fuel K, i.e. they would have been essentially
unchanged by the above-mentioned addition of additives.
Metals Content and Filtration
[0096] The metals content of Fuels H, I and J was determined using
the technique described in Example 1 with respect to Fuel A. The
average values (in ppbw) were as set out in Table 6 below:
TABLE-US-00006 TABLE 6 Metal Fuel H Fuel I Fuel J Ag <20 <20
<20 Al <100 <100 <100 B <20 <50 nd Ba <5 <5
<5 Ca <5 10 <5 Cd <5 <5 <5 Cr <5 <5 <5
Cu <5 1300 <5 Fe 5 1600 8 Mg <5 <5 <5 Mn <5 <5
<5 Mo <20 <20 <20 Na nd <200 nd Ni <20 <20
<20 P <50 270 nd Pb <50 <50 <50 Si <50 <50
<50 Sn <50 <50 <50 Ti <20 <20 <20 V <20
<20 <20 Zn 5 1400 <5 nd = not determined
[0097] The metals content of Fuel K was not measured as it would
have been the same as that of Fuel J, i.e. unchanged by the
above-mentioned addition of additives, both of which are
non-metallic materials.
Injector Fouling
[0098] The engine used in tests to determine injector fouling was
as shown in Table 7: TABLE-US-00007 TABLE 7 Type Turbocharged
indirect injection (IDI) diesel engine, type AAZ (from a Volkswagen
Passat passenger car) Number of cylinders 4 Displaced volume 1.896
L Bore 79.5 mm Stroke 95.5 mm Rated power 75 kW @ 4200 rpm Nozzles
Bosch DNOSD308 type
[0099] The engine was fitted on a test bed and the exhaust gas
recirculation (EGR) was blanked off to disable it.
[0100] The engine was run using the test fuels for 3 hours at 90 Nm
torque and 2000 rpm.
[0101] Percentage fouling is a measure of the blocking of the
injectors by deposits. This is measured by comparing the flow rate
of air sucked through at X mm injector needle lift before the
fouling test with the flow rate after the fouling test. The air
flow is measured by rotameters. For each of the four injectors on
the engine, for each of three values of X (0.1, 0.2 and 0.3), this
produces a ratio (e.g. 20 units of air flow through the new
injector, 13 units of flow after the injector was dirtied by the
test, therefore 7 units of flow lost and the fouling index of that
injector at that needle lift was 7/20=35%). The 3.times.4=12 values
are then averaged to produce one Fouling Index for that run.
[0102] The above procedure was carried out using each of Fuels H, I
and K in said engine. The measured Fouling Index in respect of each
of said fuels was as set out in Table 8: TABLE-US-00008 TABLE 8
Fuel H Fuel I Fuel K Fouling 33.56 33.73 23.74 Index %
[0103] It can be seen from the results in Table 8 that when using
Fuel I in the engine, the Fouling Index was 33.73%. However, when
using Fuel K in the engine, the Fouling Index was substantially
lower, at 23.74%. As described above, Fuel K was Fuel I which had
been passed through a clay column to form Fuel J, to which then
were added an anti-static additive ("STADIS 450", ex. Du Pont) and
lubricity additive ("R655", ex. Infineum).
[0104] Also, it can be seen from Table 6 that the level of the
metals copper, iron and zinc had been greatly reduced by said clay
treatment, i.e. as between Fuel I and Fuel J and therefore as
between Fuel I and Fuel K. This shows quite clearly that the
reduction of the level of metals in the fuel had resulted in a
greatly reduced Fouling Index.
[0105] Moreover, the results in Tables 5, 6 and 8 also show that
the Fouling Index when using Fuel K was substantially lower than
that when using Fuel H, despite the fact that the levels of metals
in Fuels H and K were essentially the same and the fact that the
density, sulfur content and distillation characteristics of Fuels H
and K were essentially the same.
[0106] The presence of said anti-static additive and lubricity
additive would have had no effect on the fouling of the injectors
and therefore it would have been expected that Fuel J would have
generated the same Fouling Index as Fuel K.
[0107] Thus, the clay treatment resulted in a fuel having
essentially the same density, sulfur content and distillation
characteristics, but exhibiting a much lower Fouling Index than
that of each of the zero diesel fuel and that fuel when doped with
copper, iron and zinc.
[0108] The reduced fouling, in turn, can reduce any power loss in
the engine or improve the power generated by the engine.
* * * * *