U.S. patent application number 11/314543 was filed with the patent office on 2006-07-27 for fuel compositions.
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 | 20060163113 11/314543 |
Document ID | / |
Family ID | 36201233 |
Filed Date | 2006-07-27 |
United States Patent
Application |
20060163113 |
Kind Code |
A1 |
Clayton; Christopher William ;
et al. |
July 27, 2006 |
Fuel Compositions
Abstract
A fuel composition containing a major amount of a fuel suitable
for use in a compression-ignition engine is disclosed. The 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. The
emission of NOx, and optionally particulates, is reduced from the
exhaust of a compression-ignition engine when such fuel composition
is introduced into the combustion chambers. The treatment includes
physical separation of the hydrocarbon component from the metal
adsorbing or absorbing phase.
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: |
36201233 |
Appl. No.: |
11/314543 |
Filed: |
December 21, 2005 |
Current U.S.
Class: |
208/15 ;
585/14 |
Current CPC
Class: |
C10L 1/08 20130101; C10L
10/02 20130101 |
Class at
Publication: |
208/015 ;
585/014 |
International
Class: |
C10L 1/08 20060101
C10L001/08 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 23, 2004 |
EP |
04258093.6 |
Apr 12, 2005 |
EP |
05252267.9 |
Claims
1. 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 emission of NOx from an exhaust of a
compression-ignition engine compared to said hydrocarbon components
that has not been treated with said metal adsorbing or adsorbing
material, said metal adsorbing or absorbing material is in a
different physical phase from the hydrocarbon component(s).
2. The fuel composition of claim 1 wherein the metal adsorbing or
absorbing material is selected from the group consisting of fibrous
clay minerals, diatomaceous earths, graphite and charcoal.
3. The fuel composition of claim 1 wherein the metal adsorbing or
absorbing material is selected from the group consisting of
polymeric adsorbents or absorbents and ion-exchange resins.
4. The fuel composition of claim 1 wherein the metal adsorbing or
absorbing material is selected from the group consisting of
complexing or chelating agents.
5. A process for the preparation of a fuel composition suitable for
use in a compression-ignition engine, which fuel comprises at least
one hydrocarbon component boiling within the diesel boiling range
comprising: treating said hydrocarbon component with a metal
adsorbing or absorbing material which is in a different physical
phase from the hydrocarbon component and is effective to reduce the
level of at least one metal; and optionally blending said at least
one hydrocarbon component, before or after said treatment, with at
least one other hydrocarbon component boiling within the diesel
boiling range thereby producing a fuel suitable for use in a
compression-ignition engine.
6. The process of claim 5 comprising blending at least two
hydrocarbon components boiling within the diesel boiling range and
treating the resulting mixture with said metal adsorbing or
absorbing material, to form a fuel suitable for use in a
compression-ignition engine.
7. A method of operating a compression-ignition engine having a
compression-ignition combustion chamber and a light duty fuel
injection system comprising: bringing into the combustion chamber a
fuel composition of claim 1; and operating the engine.
8. The method of claim 7 wherein the light duty fuel injection
system is a direct injection (DI) system or a indirect injection
(IDI) system.
9. The method of claim 8 wherein the metal adsorbing or absorbing
material is selected from the group consisting of fibrous clay
minerals, diatomaceous earths, graphite and charcoal.
10. The method of claim 8 wherein the metal adsorbing or absorbing
material is selected from the group consisting of polymeric
adsorbents or absorbents and ion-exchange resins.
11. The method of claim 8 wherein the metal adsorbing or absorbing
material is selected from the group consisting of complexing or
chelating agents.
12. A method of operating a compression-ignition engine having a
compression-ignition combustion chamber and a light duty fuel
injection system comprising: bringing 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 emission of NOx from the exhaust of said engine compared
to said hydrocarbon components that has not been treated with said
metal adsorbing or adsorbing material, said metal adsorbing or
absorbing material being in a different physical phase from the
hydrocarbon component(s); and operating the engine wherein the
light duty fuel injection system is a direct injection (DI) system
or a indirect injection (IDI) system.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to fuel compositions, to
processes for their preparation and to their use in the operation
of compression-ignition engines.
BACKGROUND OF THE INVENTION
[0002] U.S. Pat. No. 2,090,007, U.S. Pat. No. 2,338,142 or
GB-A-614636 describes treatment of hydrocarbons by passing them
through filtering or adsorbing material such as Fuller's Earth or
charcoal.
[0003] 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.
SUMMARY OF THE INVENTION
[0004] Accordingly, a fuel composition is provided 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 emission of NOx from an
exhaust of a compression-ignition engine compared to said
hydrocarbon components that has not been treated with said metal
adsorbing or adsorbing material, said metal adsorbing or absorbing
material is in a different physical phase from the hydrocarbon
component(s). A method of operating a compression-ignition engine
using such fuel composition and a process for the preparation of
such fuels are also provided.
DETAILED DESCRIPTION OF THE INVENTION
[0005] It has now been found that 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 levels of heavier metals, most
preferably the level of zinc, in said component(s), the fuel
composition exhibits reduced levels of emissions, particularly of
NOx, and optionally particulates, when used in a
compression-ignition engine to power such an engine. Said treatment
includes physical separation of the hydrocarbon component from the
metal adsorbing or absorbing phase, for example by one or more of
decanting of immiscible liquid, filtration, vortexing, centrifuging
and gravity separation.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] The New Encylopaedia Britannica, Macropaedia, Volume 4, 15th
Edition, 1984, ISBN O-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.
[0011] 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.
[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 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, for
the purpose of reducing the emission of NOx, and optionally
particulates, from a compression-ignition engine into the
combustion chambers of which said fuel composition is introduced,
said treatment including physical separation of the hydrocarbon
component from the metal adsorbing or absorbing phase.
[0014] 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.
[0015] 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.
[0016] Preferably the fibrous clay mineral is sepiolite,
attapulgite, or Fuller's Earth.
[0017] Preferably, said 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.
[0018] Preferably, examples of said diatomaceous earths are DAMOLIN
MOLER (available ex. Damolin) and HYFLO SUPER CEL (available ex.
Aldrich).
[0019] Preferably, said 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.
[0020] Preferably, said 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.
[0021] Preferably, a blend of at least two of said hydrocarbon
components has been treated with the metal adsorbing or absorbing
material.
[0022] In accordance with another embodiment of the present
invention there is also provided a process for the preparation of a
fuel composition according to the present invention which comprises
treating with a metal adsorbing or absorbing material at least one
hydrocarbon component boiling within the diesel boiling range,
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, and
optionally blending said at least one hydrocarbon component, before
or after said treatment, with at least one other hydrocarbon
component boiling within the diesel boiling range, to form a fuel
suitable for use in a compression-ignition engine.
[0023] Preferably, said process comprises blending at least two
hydrocarbon components boiling within the diesel boiling range and
treating the resulting mixture with said metal adsorbing or
absorbing material, to form a fuel suitable for use in a
compression-ignition engine.
[0024] In accordance with another embodiment of the present
invention there is further provided a method of operating a
compression-ignition engine, which comprises bringing into the
combustion chambers of such engine a fuel composition according to
the present invention. There is provided a method of operating a
compression-ignition engine having a compression-ignition
combustion chamber and a light duty fuel injection system
comprising: bringing into the combustion chamber the fuel
composition described above; and operating the engine.
[0025] In accordance with another embodiment of the present
invention there is still further provided a method of reducing the
emission of NOx, and optionally particulates, from a
compression-ignition engine which comprises bringing into the
combustion chambers of such engine a fuel composition according to
the present invention.
[0026] In accordance with another embodiment of the present
invention there is still further provided the use in a
compression-ignition engine of a fuel composition according to the
present invention for the purpose of reducing the emission of NOx,
and optionally particulates, from said engine.
[0027] In accordance with another embodiment of the present
invention there is still further provided a method of reducing the
emission of NOx, and optionally particulates, from a
compression-ignition engine which comprises replacing a fuel
composition therein by a fuel composition according to the present
invention.
[0028] Yet in accordance with another embodiment of the invention
there is provided a method of operating a compression-ignition
engine having a compression-ignition combustion chamber and a light
duty fuel injection system comprising: bringing 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 emission of NOx from the exhaust of said
engine compared to said hydrocarbon components that has not been
treated with said metal adsorbing or adsorbing material, said metal
adsorbing or absorbing material being in a different physical phase
from the hydrocarbon component(s); and operating the engine wherein
the light duty fuel injection system is a direct injection (DI)
system or a indirect injection (IDI) system.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] The base fuel may itself comprise a mixture of two or more
different diesel fuel components, and/or be additivated as
described below.
[0033] 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.
[0034] 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 to 40, more
preferably 5 to 31, yet more preferably 6 to 25, most preferably 9
to 25, and such fractions have a density at 15.degree. C. of 650 to
1000 kg/m.sup.3, a kinematic viscosity at 20.degree. C. of 1 to 80
mm.sup.2/s, and a boiling range of 150 to 400.degree. C.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] 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.
[0041] 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.
[0042] 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.
[0043] 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.
[0044] 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.
[0045] 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 of 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:
[0046] the paper by Danping Wei and H. A. Spikes, "The Lubricity of
Diesel Fuels", Wear, III (1986) 217-235;
[0047] WO-A-95/33805--cold flow improvers to enhance lubricity of
low sulfur fuels;
[0048] 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;
[0049] U.S. Pat. No. 5,490,864--certain dithiophosphoric
diester-dialcohols as anti-wear lubricity additives for low sulfur
diesel fuels; and
[0050] 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.
[0051] 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.
[0052] 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.
[0053] 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.
[0054] 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
Shell companies under the trade mark "SHELLSOL".
[0055] The total content of the additives may be suitably between 0
and 10000 ppmw and preferably below 5000 ppmw.
[0056] In this specification, amounts (concentrations, % v, ppmw,
wt %) of components are of active matter, i.e. exclusive of
volatile solvents/diluent materials.
[0057] The treatment according to the present invention may be
applied before or after any additives are blended into the fuel
composition, as appropriate.
[0058] 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.
[0059] 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.
[0060] In the diesel fuel composition, hydrocarbons can be
supplemented by oxygenates such as esters known for use in diesel
fuel.
[0061] In the process of the present invention the treatment with
the 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.
[0062] 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.
[0063] The present invention will now be further described by
reference to the following illustrative embodiments that are
provided for illustration 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
[0064] The fuels referred to in Example 1 were as set out in Table
1: TABLE-US-00001 TABLE 1 Fuel A Fuel B Property 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
[0065] 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.
[0066] 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 Filtration
[0067] 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.
[0068] 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.
[0069] 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
[0070] 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.
[0071] The levels of metals could be further reduced by the
optimisation of the operating conditions of the process, passing
the fuel through a second bed of solid, or by other means.
[0072] The clay which was employed was Attapulgite, mesh size 30-60
(0.500 to 0.250 mm), 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.
Emissions Behaviour
[0073] The emissions behaviour of Fuels A and B was then measured
using the vehicles listed in Table 3, which represent the three
major light duty fuel injection systems (common rail direct
injection (CR DI), direct injection (DI) and indirect injection
(IDI)): TABLE-US-00003 TABLE 3 Engine No. of No. of Injection
Vehicle size (L) cylinders valves system Ford Focus 1.8 4 8 CR DI
VW Golf 1.9 4 8 DI VW Passat 1.9 4 8 IDI
[0074] Fuels A and B were tested in the above vehicles in the
sequence set out in Table 4: TABLE-US-00004 TABLE 4 Vehicle Test
fuel Ford Focus A A B B A A B B VW Golf A A B B A A B B VW Passat A
A B B A A B B
[0075] Each test comprised a standard ECE+EUDC cycle (ECE 1505M 11
s 221) in which total hydrocarbons, NOx, CO, CO.sub.2 and
particulates were measured using a 2.+-.2.+-.1 bagging
strategy.
[0076] Three vehicles were tested on one fuel during each days
testing: [0077] Day 1: pre-condition all vehicles on Fuel A; [0078]
Day 2: emission test Ford Focus, VW Golf and VW Passat on Fuel A;
[0079] Day 3: emission test Ford Focus, VW Golf and VW Passat on
Fuel A, change fuel and pre-condition all vehicles with Fuel B;
[0080] Day 4: emission test Ford Focus, VW Golf and VW Passat on
Fuel B; [0081] etc.
[0082] In order to avoid trace metal contamination of the clay
treated fuel, testing was conducted from lacquer-lined fuel cans
and non-metallic fuel lines to each vehicle's fuel pump. Samples of
fuels were retained at the end of each emissions test and submitted
for elemental analysis. This confirmed that trace metal
contamination had not occurred during the course of testing.
[0083] The results of the emissions testing are set out below,
namely in Table 5 (NOx), Table 6 (particulates), Table 7 (CO),
Table 8 (total hydrocarbons) and Table 9 (CO.sub.2), the units in
all said Tables being g/km: TABLE-US-00005 TABLE 5 Fuel A Fuel B
Ford Focus 0.5114 0.5138 VW Golf 0.4236 0.3848 VW Passat 1.1849
1.1306 Fleet average 0.8043 0.7577
[0084] TABLE-US-00006 TABLE 6 Fuel A Fuel B Ford Focus 0.02836
0.02458 VW Golf 0.05665 0.05102 VW Passat 0.03843 0.03246 Fleet
average 0.04115 0.03602
[0085] TABLE-US-00007 TABLE 7 Fuel A Fuel B Ford Focus 0.166 0.163
VW Golf 0.577 0.572 VW Passat 0.245 0.249 Fleet average 0.329
0.328
[0086] TABLE-US-00008 TABLE 8 Fuel A Fuel B Ford Focus 0.038 0.037
VW Golf 0.137 0.138 VW Passat 0.019 0.018 Fleet average 0.064
0.064
[0087] TABLE-US-00009 TABLE 9 Fuel A Fuel B Ford Focus 154.28
154.54 VW Golf 133.75 127.65 VW Passat 176.20 174.51 Fleet average
154.74 152.24
[0088] It can be seen from Tables 7, 8 and 9 that the levels of CO,
total hydrocarbons and CO.sub.2 were unchanged or essentially
unchanged as between Fuels A and B. The benefits, i.e. percentage
improvement, in levels of NOx and particulates using Fuel B as
compared to using Fuel A are set out below, namely in Table 10
(NOx) and Table 11 (particulates): TABLE-US-00010 TABLE 10 NOx
benefit [%] Ford Focus 0.5 VW Golf 9.2 VW Passat 4.6 Fleet average
6.9
[0089] TABLE-US-00011 TABLE 11 Particulate benefit [%] Ford Focus
13.3 VW Golf 9.9 VW Passat 15.5 Fleet average 12.9
Example 2
[0090] The fuels referred to in Example 2 were as set out in Table
12: TABLE-US-00012 TABLE 12 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)
[0091] 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.
[0092] It can be seen that the density of Fuels C to G was
essentially unchanged by the treatment.
Metals Content and Filtration
[0093] 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 13 below.
[0094] 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.
[0095] 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.
[0096] 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.
[0097] Fuels D to G were then tested for metals content. The
average values (in ppbw) were as set out in Table 13 below:
TABLE-US-00013 TABLE 13 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
[0098] 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.
[0099] 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 NOx and particulates during engine operation.
[0100] The above data shows quite clearly that emissions of NOx and
particulates were reduced by clay treating Fuel A. This was
achieved without any essential effect on a number of fuel
properties (Table 1) or on emissions of CO, total hydrocarbons and
CO.sub.2 (Tables 7, 8 and 9).
[0101] Similar reductions in emissions of NOx and particulates are
to be expected when pre-treating the hydrocarbon component(s) of
the fuel with any metal adsorbing or absorbing material, such as
those described above, particularly those which are effective in
greatly reducing the levels of zinc in the fuel.
[0102] Therefore, the present invention provides a means for
improving, i.e. reducing, emissions from a compression-ignition
engine which comprises pre-treating with a metal adsorbing or
absorbing material at least one hydrocarbon component of a fuel to
be used in such an engine.
* * * * *