U.S. patent application number 11/488506 was filed with the patent office on 2007-02-15 for method of reducing piston deposits, smoke or wear in a diesel engine.
Invention is credited to Rinaldo Caprotti, Martin J. Willis.
Application Number | 20070033865 11/488506 |
Document ID | / |
Family ID | 35447484 |
Filed Date | 2007-02-15 |
United States Patent
Application |
20070033865 |
Kind Code |
A1 |
Caprotti; Rinaldo ; et
al. |
February 15, 2007 |
Method of reducing piston deposits, smoke or wear in a diesel
engine
Abstract
A method of reducing piston deposits, smoke or wear in a diesel
engine. The method involves the step of running the engine on fuel
comprising an oil soluble iron carboxylate or iron complex that
includes Fe.sup.3+.
Inventors: |
Caprotti; Rinaldo; (Oxford,
GB) ; Willis; Martin J.; (Bitterne, GB) |
Correspondence
Address: |
INFINEUM USA L.P.
P.O. BOX 710
LINDEN
NJ
07036
US
|
Family ID: |
35447484 |
Appl. No.: |
11/488506 |
Filed: |
July 18, 2006 |
Current U.S.
Class: |
44/640 |
Current CPC
Class: |
C10L 10/02 20130101;
C10L 1/1881 20130101; C10L 1/301 20130101; C10L 10/08 20130101;
C10L 10/06 20130101; C10L 10/04 20130101; C10L 1/188 20130101 |
Class at
Publication: |
044/640 |
International
Class: |
C10L 10/00 20060101
C10L010/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 9, 2005 |
EP |
05270036.6 |
Claims
1. A method of reducing piston deposits, smoke or wear in a diesel
engine, the method involving the step of running the engine on fuel
comprising an oil soluble or oil dispersible iron carboxylate or
iron complex that includes Fe.sup.3+; with the proviso that when
the method is a method of reducing smoke in a diesel engine, the
ratio of the number of equivalents of organic acid to the number of
equivalents of Fe.sup.3+ in the oil soluble or oil dispersible iron
carboxylate or iron complex is 3 or more.
2. The method as claimed in claim 1, wherein the iron carboxylate
or iron complex includes more than 25% of Fe.sup.3+, preferably
more than 50% of Fe.sup.3+, and most preferably more than 75% of
Fe.sup.3+.
3. The method as claimed in claim 2, wherein the iron carboxylate
or iron complex includes more than 50% of Fe.sup.3+.
4. The method as claimed in claim 3, wherein the iron carboxylate
or iron complex includes more than 75% of Fe.sup.3+.
5. The method as claimed in claim 1, wherein the iron carboxylate
or iron complex is derived from a compound of the formula: ##STR3##
where R.sub.1, R.sub.2, R.sub.3 and R.sub.4 represent hydrogen or a
hydrocarbyl having 1-30 carbon atoms (C.sub.1-C.sub.30), but at
least two of R.sub.1, R.sub.2, R.sub.3 or R.sub.4 are
C.sub.1-C.sub.30 hydrocarbyl; R.sub.5 is a hydrocarbyl having 1 to
120 carbon atoms and m and n may each be zero or an integer such
that the total number of carbon atoms in the carboxylate is not
more than 125.
6. The method as claimed in claim 5, wherein R.sub.1 and R.sub.2
are both hydrocarbyl and R.sub.3 and R.sub.4 are hydrogen.
7. The method as claimed in claim 1, wherein the fuel is a heavy
fuel oil.
8. The method as claimed in claim 1, wherein the carboxylate is
neodecanoate.
9. The method as claimed in claim 1, wherein the fuel contains 1 to
50 ppm of iron by weight of fuel.
10. The method as claimed in claim 9, wherein the fuel contains 1
to 25 ppm of iron by weight of fuel.
11. The method as claimed in claim 10, wherein the fuel contains 5
to 15 ppm of iron by weight of fuel.
12. The method as claimed in claim 1, wherein the fuel is a marine
diesel fuel and the iron carboxylate is iron neodecanoate.
13. The method as claimed in claim 1, wherein the method reduces
piston groove deposits.
14. The method as claimed in claim 1, wherein the method reduces
piston deposits and smoke, or piston deposits and wear, or smoke
and wear in a diesel engine.
Description
[0001] This invention relates to a method of reducing piston
deposits, smoke or wear in a diesel engine.
[0002] EP 689 577A discloses the use of ferrocene in fuels to
reduce deposits or to facilitate their removal. Ferrocene includes
Fe.sup.2+ only.
[0003] The aim of the present invention is to reduce piston
deposits, smoke or wear in a diesel engine. In particular, the aim
of the present invention is to reduce piston deposits, smoke or
wear in a marine diesel engine running on heavy fuel oil.
[0004] In accordance with the present invention there is provided a
method of reducing piston deposits, smoke or wear in a diesel
engine, the method involving the step of running the engine on fuel
comprising an oil soluble or oil dispersible iron carboxylate or
iron complex that includes Fe.sup.3+; with the proviso that when
the method is a method of reducing smoke in a diesel engine, the
ratio of the number of equivalents of organic acid to the number of
equivalents of Fe.sup.3+ in the oil soluble or oil dispersible iron
carboxylate or iron complex is 3 or more.
[0005] The piston deposits are preferably piston groove
deposits.
[0006] The iron carboxylate or iron complex is preferably derived
from a compound of the formula ##STR1## wherein R.sub.1, R.sub.2,
R.sub.3 and R.sub.4 represent hydrogen or a hydrocarbyl having 1-30
carbon atoms (C.sub.1-C.sub.30), but at least two of R.sub.1,
R.sub.2, R.sub.3 or R.sub.4 are C.sub.1-C.sub.30 hydrocarbyl;
R.sub.5 is a hydrocarbyl having 1 to 120 carbon atoms and m and n
may each be zero or an integer such that the total number of carbon
atoms in the carboxylate is not more than 125.
[0007] The formula above is intended to represent a carboxylic acid
which has at least two side chains of at least 1 to 30 carbon atoms
in length, and preferably both R.sub.1 and R.sub.2 are hydrocarbyl
so that the carboxylate is a neocarboxylate, i.e., having the
carbon atom which is alpha to the carbonyl carbon connected to four
other carbon atoms. The term hydrocarbyl is intended to apply to
aromatic or aliphatic radicals composed principally of carbon and
hydrogen, optionally substituted with oxygen or nitrogen,
preferably aliphatic and particularly straight or branched chain
alkyl or substituted alkyl, the substituents being nitrogen or
oxygen. Most preferably the carboxylate is a neodecanoate.
[0008] Suitable examples of R.sub.5 moieties are hydrocarbyl groups
made from homo- or interpolymers (e.g. copolymers, terpolymers) of
mono- and di-olefins having 2 to 10 carbon atoms, such as ethylene,
propylene, 1-butene, isobutene, butadiene, isoprene, 1-hexene,
1-octene, etc. Typically, these olefins are 1-monoolefins. This
hydrocarbyl can also be derived from the halogenated (e.g.
chlorinated or brominated) analogs of such homo- or interpolymers
or from polyethers.
[0009] The hydrocarbyl may be saturated. The hydrocarbyl may be
predominantly aliphatic in nature, that is, containing no more than
one non-aliphatic moiety (cycloalkyl, cycloalkenyl or aromatic)
group of 6 or less carbon atoms for every 10 carbon atoms in the
substituent. Usually, however, the hydrocarbyl contains no more
than one such non-aliphatic group for every 50 carbon atoms, and in
many cases, they contain no such non-aliphatic groups at all; that
is, the typical substituents are purely aliphatic. Typically, these
purely aliphatic hydrocarbyls are alkyl or alkenyl groups.
[0010] The hydrocarbyl may also contain some unsaturation. The
hydrocarbyl may be derived from oils from seeds, fats and trees.
Examples of oils are rapeseed oil, coriander oil, soyabean oil,
linseed oil, cottonseed oil, sunflower oil, castor oil, tall oil,
olive oil, peanut oil, maize oil, almond oil, palm kernel oil,
coconut oil, mustard seed oil, beef tallow and fish oils.
[0011] A preferred source of the R.sub.5 moiety are
poly(isobutene)s obtained by polymerization of a C.sub.4 refinery
stream having a butene content of 35 to 75 wt. % and isobutene
content of 30 to 60 wt. % in the presence of a Lewis acid catalyst
such as aluminum trichloride or boron trifluoride. These
polybutenes predominantly contain monomer repeating units of the
configuration --C(CH.sub.3).sub.2CH.sub.2--
[0012] The iron carboxylate or iron complex is preferably present
in an additive solution or dispersion. The additive solution or
dispersion will preferably comprise 10-80%, more preferably 20-70%,
most preferably 35-65%, by weight of the carboxylate or complex,
with the remainder being hydrocarbon solvent.
[0013] The iron carboxylate or complex may include mixtures of Fe
and Fe.sup.3+; however, the iron carboxylate or complex preferably
includes more than 25%, even more preferably more than 50%, of
Fe.sup.3+. More preferably, the iron carboxylate or 3+complex
includes more than 75%, and preferably more than 90%, of
Fe.sup.3+.
[0014] The iron carboxylate or complex additive may also be acidic,
that is, the iron carboxylate or iron complex composition may
contain up to about 20% of unreacted free acid such as 1-20% by
weight free acid, more preferably 0-10%, most preferably 0-5% free
acid.
[0015] The iron carboxylate or complex additive may be overbased,
acidic or neutral, but preferably is neutral.
[0016] The iron carboxylate may be neutral in that it contains a
stoichiometric ratio of iron cations to carboxylate anions. It may
also be acidic, overbased or micellised. Acidic salts contain an
excess of carboxylic acid/carboxylate over that which would be
considered stoichiometric and overbased salts contains an excess of
iron species over the stoichiometric ratio. This excess iron may
exist in one or a combination of forms including oxides, hydroxides
or mixed oxidic salts. Lattice-like polynuclear-iron complexes or
iron clusters may also be present.
[0017] For overbased carboxylates, the excess iron may be
introduced, either intentionally or unintentionally, during the
main reaction process or alternatively may be introduced subsequent
to this via post treatment. The elemental iron, oxides and
hydroxides are common feedstocks for the overbasing process.
[0018] The solvent used to prepare stable additive solutions or
dispersions may generally be characterized as a normally liquid
petroleum or synthetic hydrocarbon or oxygenated hydrocarbon or
alcohol solvents, such as hexanol, 2-ethylhexanol or isodecyl
alcohol solvent. Typical examples include kerosene, hydrotreated
kerosene, isoparaffinic and paraffinic solvents and naphthenic
aliphatic hydrocarbon solvents, aromatic solvents, dimers and
higher oligomers of propylene, butene and similar olefins and
mixtures thereof. Commercial products such as "Solvesso", "Varsol",
"Norpar" and "Isopar" are suitable. Such solvents may also contain
functional groups other than carbon and hydrogen provided such
groups do not adversely affect the performance of the additive
composition. Preferred are isoparaffinic and paraffinic hydrocarbon
solvents. Preferably, the solvent has a flash point greater than
20.degree. C., more preferably greater than 40.degree. C., most
preferably greater than 55.degree. C.
[0019] The iron carboxylates or complexes may be used as additives
in a wide variety of fuel oils, particularly diesel fuel oils and
heavy fuel oils.
[0020] Such fuel oils include "middle distillate" fuel oil which
refers to petroleum-based fuel oils obtainable in refining crude
oil as the fraction from the light, kerosene or jet fuel, fraction
to the heavy fuel oil fraction. These fuel oils may also comprise
atmospheric or vacuum distillate, cracked gas oil or a blend, in
any proportions, of straight run and thermally and/or catalytically
cracked or hydrocracked distillate. Examples include hydrocracked
streams, kerosene, jet fuel, diesel fuel, heating oil, visbroken
gas oil, light cycle oil and vacuum gas oil. Such middle distillate
fuel oils usually boil over a temperature range, generally within
the range of 100.degree. C. to 500.degree. C., as measured
according to ASTM D86, more especially between 150.degree. C. and
400.degree. C.
[0021] Preferably the fuel is residual fuel oil and the diesel
engine is a marine diesel engine, which can be 2- or 4-stroke.
[0022] Vegetable-based and fat-based fuel oils are triglycerides of
monocarboxylic acids, for example, acids containing 10-25 carbon
atoms, and typically have the general formula shown below ##STR2##
where R is an aliphatic radical of 10-25 carbon atoms which may be
saturated or unsaturated.
[0023] Generally, such oils contain glycerides of a number of
acids, the number and kind varying with the source of the vegetable
or fat.
[0024] Suitable fuel oils also include mixtures of 1-50% by weight
of vegetable oils or methyl esters of fatty acids with petroleum
based diesel fuel oils. Also suitable are fuels emulsified with
water and alcohols, which contain suitable surfactants.
[0025] Examples of oils are rapeseed oil, coriander oil, soyabean
oil, linseed oil, cottonseed oil, sunflower oil, castor oil, tall
oil, olive oil, peanut oil, maize oil, almond oil, palm kernel oil,
coconut oil, mustard seed oil, beef tallow and fish oils. Rapeseed
oil, which is a mixture of fatty acids partially esterified with
glycerol, is preferred as it is available in large quantities and
can be obtained in a simple way by pressing from rapeseed. Esters
of tall oil fatty acids are also suitable as fuels.
[0026] Further examples of vegetable-based and fat-based fuel oils
are alkyl esters, such as methyl esters, of fatty acids of the
vegetable or animal oils and fats. Such esters can be made by
transesterification.
[0027] As lower alkyl esters of fatty acids, consideration may be
given to the following, for example as commercial mixtures: the
ethyl, propyl, butyl and especially methyl esters of fatty acids
with 12 to 22 carbon atoms, for example of lauric acid, myristic
acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid,
elaidic acid, petroselic acid, ricinoleic acid, elaeostearic acid,
linoleic acid, linolenic acid, eicosanoic acid, gadoleic acid,
docosanoic acid or erucic acid, which have an iodine number from 50
to 150, especially 90 to 140, more especially 100 to 130. Mixtures
with particularly advantageous properties are those which contain
mainly, i.e. to at least 50 wt %, such as 1-5 wt. % or 1-15 wt. %
methyl esters of fatty acids with 16 to 22 carbon atoms and 1, 2 or
3 double bonds. The preferred lower alkyl esters of fatty acids are
the methyl esters of oleic acid, linoleic acid, linolenic acid and
erucic acid.
[0028] Commercial mixtures of the stated kind are obtained for
example by cleavage and esterification of natural fats and oils by
their transesterification with lower aliphatic alcohols. For
production of lower alkyl esters of fatty acids it is advantageous
to start from fats and oils with high iodine number, such as, for
example, palmoil, linseed oil, tall oil, sunflower oil, rapeseed
oil, coriander oil, castor oil, soyabean oil, cottonseed oil,
peanut oil or beef tallow. Lower alkyl esters of fatty acids based
on a new variety of rapeseed oil, the fatty acid component of which
is derived to more than 80 wt % from unsaturated fatty acids with
18 carbon atoms, are preferred.
[0029] Most preferred as a vegetable-based fuel oil is rapeseed
methyl ester.
[0030] The concentration of iron carboxylates or complexes in the
fuels is usually expressed in terms of the level of addition of the
iron from such carboxylates. These fuels preferably contain at
least 1 part to 50, preferably 1 to 25, parts of iron per million
parts (ppm) by weight of fuel, preferably from about 2 to about 20
parts, more preferably from about 2 to 10 parts, even more
preferably 5 to 10 parts, of iron per million parts of fuel.
[0031] The iron carboxylate or complex solution or dispersion can
be combined with the diesel fuel by direct addition, or as part of
a concentrate or in admixtures with other fuel additives.
[0032] The additive solution can also be maintained in a separate
fuel additive dispenser apart from the fuel. The additive solution
or dispersion can then be combined or blended with the fuel during
re-filling of the fuel tank. The additive solution or dispersion
may be maintained in the fuel additive dispenser and may form a
part of a fuel additive concentrate of the concentrate being
combined with the fuel. Other techniques comprise adding the iron
carboxylate or complex additive into the intake or exhaust manifold
or adding the additive to the fuel at fuel depots prior to filling
the fuel tank. Preferably the addition is made direct to the fuel
line prior to the main fuel pump in order to optimise mixing of the
additive within the fuel. The addition is preferably controlled by
an injection system that is capable of varying the treat rate of
fuel additive dependent on fuel flow rate, fuel type and engine
operating parameters. The injection system is preferably used with
a separate additive tank
[0033] It is preferred that the fuel is a heavy fuel oil which is
used for example in railroad, power generation and marine type
applications which employ large engines and boilers or
furnaces.
[0034] The heavy fuel may in particular have one or more of the
following characteristics: [0035] (i) a 95% distillation point
(ASTM D86) of greater than 330.degree. C., preferably greater than
360.degree. C., more preferably greater than 400.degree. C., and
most preferably greater than 430.degree. C.; [0036] (ii) a cetane
number (measured by ASTM D613) of less than 53, preferably less
than 49, more preferably less than 45; [0037] (iii) an aromatic
content of greater than 15% wt., preferably greater than 25% and
more preferably greater than 40%; [0038] (iv) a Ramsbottom carbon
residue (by ASTM D524) of greater than 0.01% mass, preferably
greater than 0.15% mass, more preferably greater than 0.3% mass,
such as 1% or 5% mass, and most preferably greater than 10% mass;
and [0039] (v) adherence to the ISO specification 8217:1996 and
modifications of said specification.
[0040] As defined earlier, marine diesel fuels may in particular
contain streams such as streams produced from fluid catalytic
cracking. Such materials usually having a density @ 15.degree. C.
of 900 to 970 kg/m.sup.3 and characterised by low cetane number
values, typically ranging from 10 or lower to around 30 to 35; from
thermal cracking processes, like visbreaking and coking. Such
streams typically having a density range @ 15.degree. C. of 830 to
930 kg/m.sup.3 and a cetane value of 20 to 50; and from
hydrocracking that uses severe conditions, e.g. temperature in
excess of 400.degree. C. coupled with pressures of 130 bars or
greater, to produce streams characterized by cetane number from 45
to 60 and having a density range @ 15.degree. C. from 800 to 860
kg/m.sup.3.
[0041] Typically, marine fuels accord with the standard
specification ASTM D-2069 and may be either distillate or residual
fuels as described within that specification, and may in particular
have sulphur contents of greater than 0.05%, preferably greater
than 0.1%, more preferably greater than 0.2% by weight, and a
kinematic viscosity of 40.degree. C. in cSt of at least 1.40.
[0042] The engines suitable in the use include compression-ignition
(diesel) engines such as those found in vehicles.
[0043] In particular, suitable engines are those larger diesel
engines of four-stroke or two-stroke design having one or more of
the following operating parameters: [0044] (i) a maximum engine
speed of no more than 2500 rpm (revolutions per minute) for
four-stroke engines, and of no more than 1500 rpm for two-stroke
engines; [0045] (ii) a power output of greater than 200 bhp (brake
horse-power); [0046] (iii) a cylinder bore dimension of greater
than 150 mm for four-stroke engines (such as greater than 200 mm)
or greater than 200 mm for two-stroke engines (such as greater than
500 mm); and [0047] (iv) a piston stroke of greater than 150 mm for
four-stroke engines (such as greater than 250 mm) or of greater
than 500 mm for two-stroke engines (such as greater than 1000
mm).
[0048] The additive can be used in four stroke marine diesel
engines defined by the above operating parameters and found
primarily in fishing vessels and other medium-sized craft. This
combination of parameters appears to correlate both with the type
of application for these engines, and also with the problems
observed during use. Alternatively, two-stroke engines lubricated
by means of a separate lubricating oil system (such as, for
example, marine diesel cylinder engines) having the above operating
parameters may be used. Such engines may also be found in
stationary applications and railway applications.
[0049] The four-stroke engines suitable in the invention preferably
possess the operating parameters (i) and (ii) as defined above,
more preferably the parameters (i), (ii) and (iii), and most
preferably the parameters (i), (ii), (iii) and (iv).
[0050] The two-stroke engines suitable in the present invention
preferably possess the operating parameters (i) and (ii) as defined
above, more preferably the parameters (i), (ii) and (iii), and most
preferably the parameters (i), (ii), (iii) and (iv).
[0051] The preferred engines are two-stroke. Particularly suitable
engines are those having a power output of above 250 bhp, and
preferably above 1000 bhp. Especially suitable are those engines
having bores of greater than 200 mm (such as greater than 500 mm)
and strokes of greater than 500 mm (such as greater than 1000 mm).
Such large two-stroke engines include the `crosshead` type engines
used in marine applications.
[0052] The engines considered for this application can also have a
variety of after treatment systems to control/reduce noxious
emissions such as NO.sub.x, particulate matter, smoke, SOX, CO and
HC. Some of these systems known in the art are: diesel particulate
filters, scrubbers, oxidation catalysts and others.
[0053] The invention will now be described, by way of example only,
with reference to the following examples:
EXAMPLES
[0054] Testing was performed using the Bolnes 3(1) DNL 190 single
cylinder test engine. The tests were run for 96 hours using an
engine speed of 500 rpm with an average power output of 110 kW.
[0055] Tests were conducted using:
[0056] i) heavy fuel oil A including 10 ppm of iron
neodecanoate;
[0057] ii) heavy fuel oil A including 10 ppm ferrocene; and
[0058] iii) heavy fuel oil A (as a control).
[0059] The test results were as follows: TABLE-US-00001 Bolnes 3
(1) DNL 190 Single Cylinder Engine Ave. Total Ave. liner Total Gap
Ring Groove Total Ave. Smoke wear Increase Wear Fill Merits Heavy
Fuel Oil A 0.0818 0.011 mm 1.55 mm 0.08 mm 3.95 g 0.76 plus iron
neodecanoate Heavy Fuel Oil A 0.1391 0.016 mm 1.95 mm 0.11 mm 4.94
g 0.67 plus ferrocene Heavy Fuel Oil A 0.0927 0.013 mm 2.15 mm 0.00
mm 4.38 g 0.74
As shown in the table above, the use of iron neodecanoate in heavy
fuel oil A produces less smoke, less wear and less piston groove
deposits than the use of ferrocene. The smoke measurements were
taken on an AVL415 smoke meter, which generated a filter smoke
number.
* * * * *