U.S. patent application number 11/341259 was filed with the patent office on 2006-09-28 for low-sulfur diesel fuel and use of fatty acid monoalkyl esters as lubricant improvers for low-sulfur diesel fuels.
This patent application is currently assigned to Martin Mittelbach. Invention is credited to Helmut Gossler, Wilhelm Hammer, Michael Koncar, Martin Mittelbach.
Application Number | 20060213118 11/341259 |
Document ID | / |
Family ID | 34085018 |
Filed Date | 2006-09-28 |
United States Patent
Application |
20060213118 |
Kind Code |
A1 |
Mittelbach; Martin ; et
al. |
September 28, 2006 |
Low-sulfur diesel fuel and use of fatty acid monoalkyl esters as
lubricant improvers for low-sulfur diesel fuels
Abstract
The invention relates to a low-sulfur diesel fuel containing a
maximum amount of 0.2% by weight of sulfur and fatty acid monoalkyl
esters in an amount of between 10 and 50,000 ppm as lubricity
improvers, with the fatty acid moieties of the fatty acid monoalkyl
esters originating from saturated fatty acids by at least 50%, in
particular by at least 70%. It has been shown that said fatty acid
esters show a substantially better lubricity improvement in a
low-sulfur diesel fuel than a biodiesel made of rape oil and soy
bean oil.
Inventors: |
Mittelbach; Martin; (Graz,
AT) ; Koncar; Michael; (Lieboch, AT) ; Hammer;
Wilhelm; (Graz, AT) ; Gossler; Helmut;
(Mooskirchen, AT) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
Martin Mittelbach
Graz
AT
BDI Anlagenbau Gesellschaft m.b.H.
Grambach/Graz
AT
Michael Koncar
Lieboch
AT
|
Family ID: |
34085018 |
Appl. No.: |
11/341259 |
Filed: |
January 27, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/AT04/00214 |
Jun 22, 2004 |
|
|
|
11341259 |
Jan 27, 2006 |
|
|
|
Current U.S.
Class: |
44/385 |
Current CPC
Class: |
C10L 10/08 20130101;
C10L 1/19 20130101 |
Class at
Publication: |
044/385 |
International
Class: |
C10L 1/18 20060101
C10L001/18 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 28, 2003 |
AT |
A 1194/2003 |
Claims
1. A low-sulfur diesel fuel containing a maximum amount of 0.2% by
weight of sulfur and fatty acid monoalkyl esters in an amount of
between 10 and 50,000 ppm as lubricity improvers, characterized in
that the fatty acid moieties of the fatty acid monoalkyl esters
originate from saturated fatty acids by at least 50%, in particular
by at least 70%.
2. A diesel fuel according to claim 1, characterized in that the
fatty acid monoalkyl esters are provided as fatty acid methyl
esters.
3. A diesel fuel according to claim 1, characterized in that the
fatty acid monoalkyl esters were produced from vegetable fats
and/or oils.
4. A diesel fuel according to claim 1, characterized in that it
additionally contains one or more additives for improving the
cetane number or for improving the low-temperature behaviour.
5. An agent for improving the lubricity of diesel fuels containing
fatty acid monoalkyl esters, characterized in that the fatty acid
moieties of the fatty acid monoalkyl esters originate from
saturated fatty acids by at least 50%, in particular by at least
70%.
6. A process for the production of a fatty acid monoalkyl ester
whose fatty acid moieties originate from saturated fatty acids by
at least 50%, in particular by at least 70%, characterized in that
a fatty acid monoalkyl ester whose fatty acid moieties originate
from saturated and unsaturated fatty acids is subjected to
fractional crystallization or distillation.
7. The use of fatty acid monoalkyl esters as lubricity improvers
for low-sulfur diesel fuels, characterized in that the fatty acid
moieties of the fatty acid monoalkyl esters originate from
saturated fatty acids by at least 50%, in particular by at least
70%.
Description
[0001] This application is a Continuation of co-pending PCT
International Application No. PCT/AT2004/000214 filed on Jun. 22,
2004, which designated the United States, and on which priority is
claimed under 35 U.S.C. .sctn. 120, the entire contents of which
are hereby incorporated by reference.
[0002] The invention relates to a low-sulfur diesel fuel containing
a maximum amount of 0.2% by weight of sulfur and fatty acid
monoalkyl esters in an amount of between 10 and 50,000 ppm as
lubricity improvers.
[0003] Legal provisions enforce a steady decrease in the content of
sulfur compounds in mineral fuels. In Europe, the content of sulfur
in diesel fuel has been limited to 0.05% by weight since 1996,
however, in several countries, e.g. in Sweden, so-called
zero-sulfur fuel having a sulfur content of less than 10 ppm is
already used almost exclusively today. A so-called city diesel
having a content of 50 ppm of sulfur is frequently offered already
today especially for use in congested areas.
[0004] The elimination of sulfur compounds during refining also
involves a deterioration of the lubricating properties of the
fuels. It has been possible to show that the elimination of sulfur
compounds is also associated with a reduction of polar, oxygenated
compounds and polycyclic aromatic compounds which are responsible
for the actual lubricity. Reduced lubricity may, however, lead to
major damage to the fuel injection pumps of diesel engines. For
this reason, it is necessary to add appropriate additives as
lubricity improvers to the diesel fuel. Conventional lubricity
improvers and additives, respectively, are either synthetic
petroleum products or synthetic esters of various chemical
structures. As an environmentally friendly alternative, renewable
raw materials such as vegetable oils or vegetable oil derivatives
such as, e.g., fatty acid monoalkyl esters are today suggested in
many cases as lubricating additives.
[0005] EP 0 680 506 B describes the use of esters as lubricity
improvers.
[0006] EP 0 635 558 A1 describes the use of fatty acid monoalkyl
esters from saturated and unsaturated fatty acid esters in an
amount of from 100 to 10,000 ppm. For this application, especially
methyl esters of the composition in which the fatty acids are
present in vegetable oils are used without any further pretreatment
or separation. A similar application can be learnt from WO
94/17160.
[0007] WO 96/07632 describes the production of agents for lubricity
improvement by double transesterification of vegetable oils,
wherein, in the first stage, fatty acid monoalkyl esters are
produced which are transesterified with a polyol in a second stage.
Similar compounds are described in EP 1 088 880 A1.
[0008] Mixtures of fatty acid esters and dicarboxylic acid esters
as lubricity improvers are described in DE 19955354.
[0009] U.S. Pat. No. 5,891,203 describes the use of a mixture of
biodiesel and diethanolamine derivatives as lubricity improvers in
low-sulfur fuels. Hereby, fatty acid amides from diethanolamine and
fatty acids are used, wherein especially oleic acid is used as the
preferred fatty acid.
[0010] In Energy and Fuels (2001, 15, 106-112), the use of
biodiesel produced from various raw materials such as sunflower
oil, corn oil, olive oil and used edible oils as an additive for
lubricity improvement is described, wherein it has been possible to
detect a distinct effect with all products, without being able to
detect any differences with the individual raw materials.
[0011] By means of the directive of the European Commission, the
amount of biofuels in the EU is meant to rise to an amount of 5.75%
by the year 2010. In order to be able to achieve that amount, it
will be necessary especially in the field of biodiesel to fully
exploit the potential of possible raw materials. This means that
raw materials such as used edible oils, animal fats or palm oil
will increasingly have to be used as raw material sources.
[0012] A substantial obstacle against using those raw materials as
biofuels is the poor low-temperature behaviour of the fatty acid
monoalkyl esters produced therefrom, whereby the application as a
biodiesel in a 100% form and also as a mixing component is
presently still highly restricted.
[0013] The present invention starts here, which has as its object
to provide an improved low-sulfur diesel fuel having a maximum
amount of 0.2% by weight of sulfur, which diesel fuel contains
fatty acid monoalkyl esters in an amount of between 10 and 50,000
ppm as lubricity improvers and with which the above-mentioned
problem is diminished.
[0014] The low-sulfur diesel fuel according to the invention
contains a maximum amount of 0.2% by weight of sulfur and fatty
acid monoalkyl esters in an amount of between 10 and 50,000 ppm as
lubricity improvers and is characterized in that the fatty acid
moieties of the fatty acid monoalkyl esters originate from
saturated fatty acids by at least 50%, in particular by at least
70%, with the fatty acid monoalkyl esters preferably being provided
as fatty acid methyl esters.
[0015] The present invention is based on the surprising realization
that the lubricating ability of fatty acid monoalkyl esters
apparently depends on the content of saturated fatty acid
derivatives. For instance, it has been possible to show that fatty
acid esters having a content of more than 50% of saturated fatty
acids show a substantially higher lubricity improvement in a
low-sulfur diesel fuel than a biodiesel made of rape oil or soy
bean oil.
[0016] Via fractional crystallization and distillation, the amounts
of esters comprising unsaturated fatty acids can be separated off.
Thus, in particular the fatty acid ester fractions which are
obtained by fractional crystallization or distillation and are
characterized by a high content of saturated fatty acids are
particularly well suited as lubricity improvers.
[0017] The fatty acid monoalkyl esters contained in the diesel fuel
according to the invention are preferably produced from vegetable
fats and/or oils. Possible raw materials are all natural vegetable
or animal oils and/or fats whose content of saturated fatty acids
already amounts to more than 50%, or corresponding products which
were produced by enrichment or separation of the saturated fatty
acids from the respective oils and fats. Preferably, appropriate
fractions from the processing of palm oil (palm stearin) or animal
fat fractions are used.
[0018] A further embodiment of the diesel fuel according to the
invention is characterized in that it additionally contains one or
more additives for improving the cetane number or for improving the
low-temperature behaviour.
[0019] Furthermore, the invention relates to an agent for improving
the lubricity of diesel fuels containing fatty acid monoalkyl
esters which is characterized in that the fatty acid moieties of
the fatty acid monoatkyl esters originate from saturated fatty
acids by at least 50%, in particular by at least 70%.
[0020] Furthermore, the invention relates to a process for the
production of a fatty acid monoalkyl ester whose fatty acid
moieties originate from saturated fatty acids by at least 50%, in
particular by at least 70%, which process is characterized in that
a fatty acid monoalkyl ester whose fatty acid moieties originate
from saturated and unsaturated fatty acids is subjected to
fractional crystallization or distillation.
[0021] Finally, the invention relates to the use of fatty acid
monoalkyl esters as lubricity improvers for low-sulfur diesel
fuels, with the fatty acid moieties of the fatty acid monoalkyl
esters originating from saturated fatty acids by at least 50%, in
particular by at least 70%.
[0022] As a measuring method for determining lubricity, the HFRR
wear test as per CEC F-06-A-96 was used in accordance with
international standards. Here, lubricity is determined by way of
the abrasion of a rotating ball. In this method, an abrasion of 460
.mu.m is regarded as the threshold value. The reference fuel used
for the tests was a sulfur-free, non-additivated diesel fuel having
an abrasion value of 569 .mu.m.
[0023] When using different biodiesel samples (made of animal fat,
rape oil, soy bean oil and used edible oil), it was surprisingly
possible to detect that, when added in an amount of 0.5%, all
biodiesel samples did indeed result in an enhancement of
lubricating properties but that only by means of the agent
according to the invention it was possible to substantially fall
below the threshold value of 460 .mu.m. Only when 1.0% was used,
the biodiesel samples from rape oil and used edible oil were also
able to fall below the threshold value whereas, in case of
biodiesel from soy bean oil, even an addition of 2.0% did not
result in the threshold value being fallen short of.
[0024] Various palm oil samples and palm oil fatty acids,
respectively, having high contents of saturated fatty acids were
also used for the production of fatty acid methyl esters. All
samples had a content of saturated fatty acids of more than 50%.
With all samples, it was possible to fall below the threshold value
of 460 .mu.m at least when 1.0% was used.
[0025] According to European Standard EN 590, an additivation by
5.0% is permitted in a mineral diesel fuel. Since, if additives are
used, the price of the additive plays a decisive role and
conventional lubricity improvers are available at very low prices,
the use of fatty acid alkyl esters is interesting from an economic
point of view only if the lowest possible amount of additive is
used.
[0026] Thus, fatty acid monoalkyl esters having a content of
saturated fatty acids of more than 50% constitute ideal additives
for improving the lubricating properties of sulfur-free diesel
fuels.
[0027] By means of the following examples, preferred embodiments of
the invention are illustrated further.
EXAMPLE 1
[0028] The starting product was an animal fat having the following
fatty acid composition:
Lauric acid: 0.2%
Myristic acid: 1.86%
Palmitic acid: 25.17%
Stearic acid: 14.47%
Oleic acid: 42.98%
Linoleic acid: 9.24%
[0029] According to known methods, said fat was converted with
methanol and potassium hydroxide into the corresponding fatty acid
methyl esters. Via fiactional crystallization, the fatty acid
methyl esters obtained were separated into two fractions at low
temperatures, wherein the fraction having a high content of
saturated fatty acids was used as a lubricant additive. The fatty
acid composition of said fraction was as follows:
Lauric acid: 2.06%
Myristic acid: 0.44%
Palmitic acid: 33.75%
Stearic acid: 35.00%
Oleic acid: 21.26%
Linoleic acid: 2.62%
[0030] Mixtures of said fraction with a non-additivated sulfur-free
diesel fuel were produced and the lubricity was determined by
evaluating the HFRR wear test as per CEC F-06-A-96.
[0031] By way of comparison, different biodiesel samples produced
from rape oil, soy bean oil and used edible oil were likewise
assessed by the same test. TABLE-US-00001 Methyl ester sample 0.5%
1.0% 2.0% Methyl ester from animal fat 443 420 321 after fract.
crystallization Rape oil 509 359 320 Used edible oil 521 375 322
Soy bean oil 540 483 487
HFRR abrasion values in .mu.m; reference value of non-additivated
fuel: 569 .mu.m Example 2
[0032] A technical fatty acid distillate made of palm oil and
having the following fatty acid composition was used as a raw
material for the production of fatty acid methyl esters:
Myristic acid: 1.59%
Palmitic acid: 52.07%
Stearic acid: 3.93%
Oleic acid: 33.80%
Linoleic acid: 8.37%
Said fatty acid mixture was converted with the aid of methanol and
concentrated sulfuric acid as a catalyst, whereby the corresponding
fatty acid methyl esters were obtained.
[0033] Mixtures of said fatty acid methyl esters with a
non-additivated sulfur-free diesel fuel were produced and the
lubricity was determined by evaluating the HFRR wear test as per
CEC F-06-A-96. TABLE-US-00002 Amount of methyl ester 0.5% 1.0% HFRR
426 367
HFRR abrasion values in .mu.m; reference value of non-additivated
fuel: 569 .mu.m Example 3
[0034] Palm stearin produced by fractional crystallization from
palm oil and having the following fatty acid composition was used
as a raw material for the production of fatty acid methyl
esters:
Myristic acid: 1.3%
Palmitic acid: 73.83%
Stearic acid: 4.84%
Oleic acid: 16.56%
Linoleic acid: 3.52%
[0035] With the aid of methanol and potassium hydroxide as a
catalyst, palm stearin was subjected to multistage
transesterification, whereby the corresponding fatty acid methyl
esters were obtained.
[0036] Mixtures of said fatty acid methyl esters with a
non-additivated sulfur-free diesel fuel were produced and the
lubricity was determined by evaluating the HFRR wear test as per
CEC F-06-A-96. TABLE-US-00003 Amount of methyl ester 0.5% 1.0% HFRR
534 447
HFRR abrasion values in .mu.m; reference value of non-additivated
fuel: 569 .mu.m
EXAMPLE 4
[0037] Raw palm oil having the following fatty acid composition was
used as a raw material for the production of fatty acid methyl
esters:
Myristic acid: 1.07%
Palmitic acid: 44.23%
Stearic acid: 4.68%
Oleic acid: 38.28%
Linoleic acid: 11.74%
[0038] With the aid of methanol and potassium hydroxide as a
catalyst, said palm oil was subjected to multistage
transesterification, whereby the corresponding fatty acid methyl
esters were obtained.
[0039] Mixtures of said fatty acid methyl esters with a
non-additivated sulfur-free diesel fuel were produced and the
lubricity was determined by evaluating the HFRR wear test as per
CEC F-06-A-96. TABLE-US-00004 Amount of methyl ester 0.5% 1.0% HFRR
477 456
HFRR abrasion values in .mu.m; reference value of non-additivated
fuel: 569 .mu.m
* * * * *