Note: Descriptions are shown in the official language in which they were submitted.
. 2156747
2
USE OF FERROCENE
The invention relates to the use of ferrocene and/or ferrocene
derivatives as an additive to heavy grade internal combustion
engine fuels for high-compression spontaneous-ignition engines.
Ferrocene and its derivatives are known from specialist
literature. Ferrocene and its production Were described for the
first time in 'Nature' 67~ (1951) page 1039. Subsequently,
ferrocene and its derivatives, as well as corresponding
production processes, have been the subject-matter of numerous
patents, e.g. US 2 650 756, US 2 769 828, US 2 834 796, US 2 898
360, US 3 035 968, US 3 238 158 and US 3 437 634.
It is also known from the patent literature that ferrocene can
advantageously affect combustion processes. DE Patent 34 18 648,
in addition to many other compounds, also mentioned ferrocene
(dicyclopentadienyl iron) as a possible additive for the purpose
of optimizing the combustion of fuel oil, i.e. to facilitate the
transportation of the fuel oil through the burner and to promote
the complete combustion of the fuel oil.
A process to condition a diesel engine is described in US Patent
4 389 220. To this end, 20 to 30 ppm of ferrocene are added to
the diesel fuel. It is intended, hereby, to remove carbonaceous
deposits in the combustion chamber and to prevent any renewed
formation thereof. It was simultaneously found that the fuel
2156747
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consumption per distance travelled was reduced by up to 5% as a
result of this measure. The term diesel fuel in the present
instance relates to a fuel which is known, according to ASTM, as
"No. 2 fuel oil". A fuel of this kind is a middle distillate
from the petroleum refinery process and is available at filling
stations under-the term "Diesel". The four-stroke diesel engines
of road vehicles, e.g, passenger cars, buses, commercial
vehicles, are usually run on this fuel. Said fuel conforms to
DIN 51601 and, in its quality, is similar to the EL fuel oil.
It is thus a light to medium grade fuel.
Heavy grade fuels are used for larger lower speed engines such
as are used, for example, in ships or current-generating plants.
Here, the problem arises that the performance of downstream units
is adversely affected by carbonaceous deposits. Such units
include, in particular, turbochargers as well as heat exchangers.
Deposits on valves, piston rings and in the combustion chamber
are, however, also undesirable, since they may lead to a
reduction of the engine performance and/or to an increased wear
of the parts concerned.
It is the object of the invention to minimize the above-mentioned
deposits or to facilitate the removal thereof.
According to the invention, there is provided the use of
ferrocene and/or ferrocene derivatives as an additive in heavy
grade internal combustion engine fuels for high-compression
spontaneous-ignition engines. The invention may be applied, in
CA 02156747 2004-04-15
4
particular, to fuels having a density of 0.9 to 1.01
kg/dm' .
According to one aspect of the present invention there is
provided a process for reducing carbonaceous deposits
resulting from the combustion of heavy residual fuel oil
in a low-speed, high-compression, spontaneous-ignition
internal combustion engine having a speed of 900 to 50
revolutions per minute, which comprises adding at least
one additive selected from the group consisting of
ferrocene, ethyl ferrocene, butyl ferrocene and 2.2 bis-
ethyl ferrocenyl propane to a heavy fuel oil having a
density of 0.9 to 1.01 kg/dm', the heavy fuel oil being a
heavy residual fuel oil, in an amount of 1 to 100 ppm
prior to combustion of the residual fuel oil and
combusting the residual fuel oil containing the at least
one additive in the low-speed, high-compression,
spontaneous-ignition internal combustion engine having
the speed of 900 to 50 revolutions per minute.
According to another aspect of the present invention
there is provided a commercial package comprising a heavy
residual fuel oil having a density of 0.9 to 1.01 kg/dm3
for combustion in a low speed, high-compression,
spontaneous-ignition internal combustion engine having a
speed of 900 to 50 revolutions per minute, the fuel oil
further comprising from 1 to 100 ppm of at least one
additive selected from the group consisting of ferrocene,
ethyl ferrocene, butyl ferrocene and 2.2-bis-ethyl
ferrocenyl propane together with instructions for the use
thereof as a combustion fuel in said spontaneous-ignition
internal combustion engine.
The use of ferrocene as an additive has surprisingly
proved to be particularly advantageous, in particular
when operating large engines of this kind using heavy
fuels. This holds true, primarily, in respect of
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relatively large engines' i.e. engines having a total
output of 400 to 100.000, preferably 15.000 to 50.000
and, in particular, of more than 30.000 kW.
As a rule, problems associated with the above-mentioned
deposits increase with an increasingly heavy fuel. In the
case of said fuels, the use of ferrocene as an additive
has surprisingly proved to be particularly effective.
This was not to be expected, especially since it was
known that ferrocene is very effective in improving the
combustion of light fuel oil, but that it was less
effective in the case of heavy fuel oil.
The use according to the invention is particularly
advantageous for grades which are usually designated as
marine fuel oil, "Bunker C" grade, marine diesel fuel, or
distilled marine diesel fuel. As can readily be seen from
the names of the fuel grades, these are chiefly used to
run marine engines.
The fuels in question can, for example, be residues from
the atmospheric distillation of crude oil, from vacuum
distillation or from a catalystic cracking plant. The
density of said fuels in particular ranges between
0.9 and 1.0 kg/dm'. Said fuels may be classified
more accurately by referring to ISO 82 17
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According to said standardization, a distinction of two classes
of fuels is made, so-called distilled marine fuels (marine
distillate fuels) and so-called heavy residual fuels. The first-
mentioned group are given a DM type designation and the second
group an RM type designation. Certain types are listed below by
way of example, setting out their most significant properties
such as the density, viscosity, sulphur content and the carbon
residue.
DMB DMC RMA RMG RMH
10 35 45
density kg/dm'0.9D 0.92 0.95 0.9911.010
max. kinematic
viscosity
cSt at 40C 11.0 14.0 -- - --
at 100C - -- 10 35 45
max. carbon
residue
96 by mass 0.25 2.5 12 18 22
max. sulphur
content
96 by mass 2.0 2.0 3.5 5.0 5.0
All the DM RM types be used fuels withinthe context
and can as
of the presentinvention.
Many ship engines of large ocean-going ships are two-stroke
engines. The invention is particularly applicable to such
engines. The invention may thus extend to the use of ferrocene
and/or ferrocene derivatives as an additive in fuels used to run
21674?
t.
6
two-stroke engines. This is particularly the case when said
engines are low-speed engines, having a speed of 900 to 50,
preferably 200 to 50 revolutions per minute, in particular a
maximum speed of 100 revolutions per minute, or less. Good
results can, however, also be achieved by the addition according
to the invention in engines having a higher speed as well as in
four-stroke engines. The invention may thus extend to the use
of ferrocene and/or ferrocene derivatives as an additive in fuels
used to run four-stroke engines.
Good results were achieved with a ferrocene addition of 1 to 100
ppm. With an addition of less than 1 ppm, the effects are not
as distinct, such that it is not possible to speak of a
substantial improvement in comparison to a fuel without an
additive. In the case of an additive content in excess of 100
ppm, a limit is reached at which any additional additive causes
no additional effect worth mentioning. As a rule, a range of
from 5 to 50 ppm is preferred. An optimal range is from 10 to
30 ppm. The additive addition may, for example, be effected such
that the additive is dissolved in part of the fuel, and this
solution is then again recycled, for example, via a metering
pump, to the main fuel flow.
It is possible, at least in part, to use ferrocene derivatives
instead of ferrocene. Ferrocene derivatives are compounds in
which, starting from the ferrocene parent substance, additional
substituents are disposed on one or both cyclopentadienyl rings.
Examples hereof are ethyl ferrocene, butyl ferrocene, acetyl
216747
ferrocene and 2,2-bis-ethyl ferrocenyl propane.
It is an advantage of the invention that the deposits which
originate from the heavy grade fuel used, but also originating
from the lubricating oil, are reduced effectively.
The performance of downstream units, such as turbochargers and
heat exchanger, as well as engine parts, such as valves and
piston rings, is adversely affected, partly to a considerable
extent, by the deposits. Considerable effort and expense are
frequently required in order to remove the deposits. Thus, for
example, it is common in large ocean-going ships to blow crushed
nut shells or even rice into the flow of exhaust gas, in order
to clean the downstream turbocharger. The greater portion of the
deposits is removed from the blade wheels, and also from the
upstream nozzle ring, by this so-called 'soft-blasting'. The
afore-mentioned procedure is usually carried out daily and, if
necessary, even twice daily, while maintaining the full engine
load. This method of cleaning is, however, usually not adequate.
A washing with water is, therefore, additionally carried out
about once a month, or more frequently if required. Since such
a washing operation is carried out while the engine load is
reduced, a delay for the ship is always involved. During the
washing operation, water is introduced into the flow of exhaust
gas through a nozzle upstream of the nozzle ring and the blade
wheels. said water-washing operation involves a considerable
stress for the turbocharger and other parts, as a result of the
thermal shock effect. Accordingly, attempts are made to reduce
. . 215674?
8
this water-washing operation to a minimum. The usual time
required for such a washing operation is about 2 to 3 hours. The
guiding factor, in this regard, is simply the clarity of the
water after the rinsing steps. In this connection, the washing
water is usually clearly noticeably heavily soiled for 1 to 2
hours. ~ As a result of the use, according to the invention, of
fuel comprising ferrocene as an additive, both 'soft-blasting'
and the water-washing operation are generally rendered
superfluous. This protects the units concerned, without any
restriction in performance, and saves time and~cuts down on
labour input.
When the performance of the turbochargers is adversely affected
by deposits, a number of problems may occur. The effectiveness
of the turbochargers and, ultimately, therefore also of the
entire machine, is reduced, such that a higher fuel consumption
is brought about. The deposits may bring about a reduction in
speed, down to, in extreme cases, a stoppage of one or more of
the blade wheels of the turbocharger. In the case of machines
with multiple turbochargers, the blade wheels are supplied with
exhaust gas from a common exhaust gas receiver which brings
together the exhaust gas from a plurality of cylinders. If the
gas is distributed non-uniformly, as a result of the varying flow
resistance which, in turn, is caused by the deposits, a drop in
speed, a fluctuation in the speed, or a considerable difference
in spees~ between the coupled turbochargers, or even a stoppage
may occur. The above-mentioned problems, which must be
attributed to the deposits, may result in premature material
215677
9
fatigue or, in extreme cases, to material failure. In the case
of particularly heavy deposits, this may also occur in smaller
machines which are not equipped with multiple turbochargers.
Irregular speed, i.e. an inconstant running, can result in very
strong vibrations which can cause, in a short period of time,
material damage in the bearings and other machine parts.
Although non-uniform deposits on the blade wheels do not
necessarily cause a drop in speed or speed differences, in the
case of multiple turbochargers, they do, however, cause
undesirable vibrations, as a result of the running out of true,
and said vibrations may also be the cause of an increased rate
of wear.
Without the additive used according to the invention, it can also
be noted in the downstream heat exchangers that deposits form on
the heat exchanger surfaces, which deposits, depending on the
thickness thereof, impede the exchange of heat. These deposits,
which contain mainly carbon, must also be removed from time to
time, by means of water-washing, optionally with cleaning
additives, e.g, a CuClz solution. As a result of the use,
according to the invention, of fuels comprising ferrocene as an
additive, the formation of deposits is greatly reduced. When a
water-washing operation does become necessary (e.g. in a dry
dock) after a period of time which is considerably longer than
in the .case of the state of the art, it is noted that the
deposits can be removed far more readily after use, according to
the invention, of the fuel comprising the additive. This may
2I56747
possible be attributed to an altered composition of the deposits.
It was noted that said deposits had a higher ash content, lower
thermal values and a lower carbon content, in contrast to
deposits when using fuels with an additive. It may be assumed
that said deposits are hydrophobic to a lesser degree, since they
contain fewer oily or oil-like components.
As a rule, such water-washing operations of the heat exchangers
or of the boiler are carried out, at the latest, every two years
when the ship is stationed in a dry dock for regulation
maintenance and inspection work. Five or six additional washing
operations are, however, normally required between two dry dock
stopovers. I~f the present invention is applied, said additional
washing operations can be dispensed with.
The invention will now be described by way of non-limiting
example with reference to the accompanying Figure 1 which
diagrammatically shows the exhaust gas route of a ship's engine
of the described magnitude. The Figure shows the engine bed (1)
with a total of 10 cylinders (2). The exhaust gases from, in
each case, 3 or 4 cylinders, respectively, are brought together
in a so-called exhaust gas 'receiver' (3, 4, 5) and are admitted
to the turbochargers (6, 7, 8). The streams of exhaust gas
flowing out of the turbochargers are brought together in an
exhaust gas pipe (9) and then flow through a so-called exhaust
gas 'boiler' (1o) in which are arranged heat exchangers (11, 12,
13), by means of which it is possible to produce high-pressure,
medium-pressure and low-pressure steam. The exhaust gases leave
2ms74~
11
the system via the funnel (14).
The invention was successfully tested on a container ship, with
the following results.
Technical data of the ship:
60.000 gross registered tons
Technical data of the engine:
output: 33.000 kW
cubic capacity: 10 cylinders @ 1.6 m3
speed: max. 90 rpm
speed of turbocharger: about 10.000 rpm
consumption: about 6 t/h at full load
After a successful starting phase, the turbochargers of the
engine of this ship were thoroughly cleaned by 'soft-blasting'
and a water-washing operation. Approximately 3 months later,
without any interim cleaning operations having been carried out,
a water-washing operation was undertaken. Although said water-
washing operation was not necessary from a technical point of
view, since the turbochargers worked satisfactorily, it was
undertaken so as to provide information on the degree of
pollution (deposits). Whereas, according to the state of the
art, it was necessary to carry out a 'soft-blasting' operation
on a daily basis and, once a month, a water-washing operation,
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in the course of which the washing water used remained heavily
polluted for 1 to 2 hours, in the present case all cleaning
operations were dispensed with for nearly 3 months (85 days) and
the washing water nonetheless remained clear from the start.
This permits the conclusion that practically no deposits formed
during the period mentioned. Even sites which cannot be reached
with the usual cleaning methods, showed no dirt deposits or
clearly reduced dirt deposits.
In the case of the heat exchangers, it was possible, already
visually, to note that distinctly fewer deposits had formed. It
was far more readily and rapidly possible to remove the deposits
which had formed than was possible heretofore when using the
water-washing operation.
In addition, no deposits were visually noted on the piston rings
and on the valves.
