U.S. patent application number 10/440169 was filed with the patent office on 2004-11-25 for palm diesel with low pour point for climate countries.
Invention is credited to Basiron, Yusof, Foon, Cheng Sit, Liang, Yung Chee, May, Choo Yuen, Nang, Harrison Lau Nik, Ngan, Ma Ah.
Application Number | 20040231234 10/440169 |
Document ID | / |
Family ID | 33449774 |
Filed Date | 2004-11-25 |
United States Patent
Application |
20040231234 |
Kind Code |
A1 |
May, Choo Yuen ; et
al. |
November 25, 2004 |
Palm diesel with low pour point for climate countries
Abstract
The present invention also discloses the processes of producing
the low pour point palm diesel particularly but not exclusively via
esterification of C18, C18:1 and C18:2 mixed fatty acids with
methanol or ethanol, or fractional distillation of methyl or ethyl
esters of palm oil, palm kernel oil and palm oil products, or
fractional distillation of methyl or ethyl esters of palm oil, palm
kernel oil and palm oil products, followed by crystallisation, or
crystallisation of methyl or ethyl esters of palm oil, palm kernel
oil and palm oil products, or crystallisation of methyl or ethyl
esters of palm oil, palm kernel oil and palm oil products, followed
by fractional distillation.
Inventors: |
May, Choo Yuen; (Kajang,
MY) ; Foon, Cheng Sit; (Kajang, MY) ; Liang,
Yung Chee; (Kajang, MY) ; Nang, Harrison Lau Nik;
(Kajang, MY) ; Ngan, Ma Ah; (Kajang, MY) ;
Basiron, Yusof; (Kajang, MY) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
33449774 |
Appl. No.: |
10/440169 |
Filed: |
May 19, 2003 |
Current U.S.
Class: |
44/388 ;
44/308 |
Current CPC
Class: |
C10L 1/1802 20130101;
C10L 1/19 20130101 |
Class at
Publication: |
044/388 ;
044/308 |
International
Class: |
C10L 001/18 |
Claims
1. Biodiesel from palm oil, palm kernel oil and/or palm oil
products or any mixture thereof characterized in that the biodiesel
consists of at least C18, C18:1 and C18: 2 methyl or ethyl esters
or a combination thereof.
2. Biodiesel as claimed in claim 1 wherein the C18, C18:1 and C18:
2 methyl or ethyl esters or mixtures thereof are mixed in a
proportion to yield a pour point between -12.degree. C. and
-21.degree. C.
3. Biodiesel as claimed in claim 2 wherein the proportion consist
less than 10% saturated methyl esters or ethyl esters or a mixture
thereof and at least 90% of C18:1 or C18:2 or a mixture thereof of
methyl or ethyl esters.
4. Biodiesel as claimed in claim 3 wherein the methyl esters
consists of methyl myristate, methyl palmitate, methyl oleate and
methyl linoleate.
5. Biodiesel as claimed in claim 4 wherein methyl ester composition
comprises of 0.5% methyl myristate, 5.0% methyl palmitate, 83.6
methyl oleate and 11.0% methyl linoleate to yield a pour point of
-21.degree. C.
6. Biodiesel as claimed in claim 4 wherein methyl ester composition
comprises of 0.6 methyl myristate, 5.7 of methyl palmitate, 2.0%
methyl stearate, 79.0 methyl oleate and 12.7% methyl linoleate
linoleate to yield a pour point of -15.degree. C.
7. Biodiesel as claimed in claim 4 wherein a mixture containing
0.6% methyl myristate, 6.3% of methyl palmitate, 2.9% methyl
stearate, 74.6% methyl oleate and 15.7% methyl linoleate to yield a
pour point of -12.theta.C.
8. Biodiesel as claimed in claim 4 wherein a mixture containing
0.7% methyl myristate, 6.7% of methyl palmitate, 0.4% methyl
stearate, 75.5% methyl oleate and 16.7% methyl linoleate to yield a
pour point of -9.theta.C.
9. Biodiesel as claimed in claim 4 wherein a mixture containing
1.64% methyl myristate, 5.04% of methyl palmitate, 0.65% methyl
stearate, 72.85% methyl oleate, 19.38% methyl linoleate and 0.45%
methyl arachidate to yield a pour point of -33.theta.C.
10. Biodiesel from palm oil, palm kernel oil and/or palm oil
products or any mixture thereof characterized in that a mixture of
methyl or ethyl esters of palm oil, palm kernel oil and palm oil
products in any combination has lower than 7% of total saturated
methyl or ethyl esters and at least 70% C18:1 methyl or ethyl ester
or mixture thereof.
11. Biodiesel as claimed in claim 10 wherein the total saturated
methyl or ethyl esters consists of C14 methyl or ethyl ester, C16
methyl or ethyl ester and C18 methyl or ethyl ester.
12. A process to synthesize biodiesel consisting of C18, C18:1 and
C18:2 methyl or ethyl esters or a mixture thereof by any one of
processes consisting of:--a)esterification of mixture of C18, C18:1
and C18:2 fatty acids; or b) fractional distillation of methyl or
ethyl esters from palm oil, palm kernel oil and palm oil products,
or c) crystallisation of methyl or ethyl esters from palm oil, palm
kernel oil and palm oil products, or d) integrated fractional
distillation and crystallisation of methyl or ethyl esters of palm
oil, palm kernel oil and palm oil products.
13. A process to synthesize biodiesel as claimed in claim 12
wherein the esterification process in step (a) is carried out using
at least C18:1, C18:2 fatty acids or a mixture thereof at a
temperature between 110.degree. C. and 160.degree. C. with an acid
catalyst.
14. A process to synthesize biodiesel as claimed in claim 13
wherein the acid catalyst is selected from concentrated sulphuric
acid, concentrated hydrochloric acid and/or sulphonic acid at a
concentration of 0.5%-1% of the total mixture.
15. A process to synthesize biodiesel as claimed in claim 12
wherein the fractional distillation process in step (b) is carried
out at a pressure of 5 Pa to 30 Pa.
16. A process the synthesize biodiesel as claimed in claim 12
wherein the crystallization process in step (c) and (d) wherein it
is dry or solvent fractionation.
17. A process to synthesize biodiesel as claimed din claim 16
wherein alcohol selected from the group consisting of methanol,
ethanol, isopronoll or a mixture thereof is used in solvent
fractionation process.
18. A process to synthesize biodiesel from palm oil, palm kernel
oil or palm oil products or from mixture thereof wherein the
biodiesel is methyl or ethyl esters or mixtures thereof and
synthesized via transesterification of palm oil and methanol and
ethanol respectively.
19. A process to sythesize biodiesel from palm oil as claimed in
claim 18 wherein the transesterification process is carried out
using palm oil, palm kernel and palm oil products with methanol or
ethanol at a temperature of 60.degree. C. to 65.degree. C. for 45
minutes to 1 hour and using 0.25% to 1% alkaline catalyst selected
from a group consisting of sodium hydroxide and sodium methylate.
Description
FIELD OF INVENTION
[0001] The present invention relates to a biofuel with improved
cold temperature flow characteristics without any additives. More
particularly but not exclusively, it relates to an improved biofuel
from palm oil, palm kernel oil and palm oil products as a
substitute for petroleum diesel.
BACKGROUND ART
[0002] Due to increased environmental consciousness, the concept of
using vegetable oil as a fuel has developed in recent years. In
Malaysia, biodiesel has been successfully derived from palm oil.
Patent No. PJ1105/88 reveales a process of producing palm oil
methyl esters (palm diesel) from palm oil. Palm oil is converted
into palm oil methyl esters via transesterification and the derived
palm oil methyl esters or palm diesel have proven to exhibit good
fuel properties and are able to be used as a diesel substitute.
`Production and Evaluation of Palm Oil Methyl Esters as Diesel
Substitute` published in Elaeis Special Issue, November 1995,
ppl5-25 discloses the fuel characteristics of palm diesel and also
its potential to be used as a diesel substitute.
[0003] However, palm oil methyl esters being evaluated of having
pour point of +15.theta.C to +18.theta.C has a limitation to its
usage or consumption as a fuel especially in cold climate
countries. Although palm diesel exhibits good fuel properties and
able to meet the fuel specifications, some problems arise when it
is used in low operational temperature. This is because the pour
point of palm oil methyl esters is +15.theta.C to +18.theta.C. Pour
point is the temperature of the oil 3.theta.C above the point at
which the test sample will not move when tipped out of the
horizontal.
[0004] The fluidity of a fuel in an engine or machine is very
important under all circumstances. When starting up an engine from
cold, it is vital that the mechanical parts are able to move freely
and there is no difficulty in transporting the fuel through lines
and pumps. Failure to do so will lead to blockage and the engine or
machine may become inefficient and inoperable.
[0005] When fuel is cooled to low temperature, it can undergo a
number of changes, namely solidification, solidification with the
formation of a precipitate of macrocrystals and solidification with
the formation of microcrystals, which swell, giving a crystalline
structure that traps the remaining oil. Under these environments,
restriction in the flow of the fuel occurs. Thus, good low
temperature flow characteristics (pour point) of a fuel is
essential to ensure smooth operation and to be suitable for various
applications. A fuel is necessary to have good pour point, which is
the temperature of the oil 3.theta.C above the point at which the
oil will not move when tipped out of the horizontal. The pour point
should be below the operational temperature.
[0006] To improve the low temperature characteristics mentioned
earlier, pour point depressants are normally employed. They act
through surface adsorption on to the wax crystals. The resulting
surface layer of the pour point depressant inhibits the growth of
the wax and paraffin crystals. Thus, in the absence of long
inter-locking crystals or swollen particles, fuel can move freely.
However, these additives though blended into the fuel in small
quantity, they are costly.
SUMMARY OF THE INVENTION
[0007] The present invention relates to a biofuel with improved
cold temperature flow characteristics without additives (pour point
depressant). More particularly but not exclusively, it relates to
an improved biofuel as a substitute for petroleum diesel from palm
oil, palm kernel oil and palm oil products.
[0008] The present invention discloses the premium grade palm
diesel composition and its good low temperature properties.
Contrary to the palm oil methyl esters, the disclosed premium grade
palm diesel (biodiesel) will be suitable to be used in cold climate
countries.
[0009] The present invention also discloses the processes of
producing the low pour point palm diesel particularly but not
exclusively via
[0010] (1) esterification of C18, C18:1 and C18:2 mixed fatty acids
with methanol or ethano, orl
[0011] (2) fractional distillation of methyl or ethyl esters of
palm oil, palm kernel oil and palm oil products, or
[0012] (3) fractional distillation of methyl or ethyl esters of
palm oil, palm kernel oil and palm oil products, followed by
crystallisation, or
[0013] (4) crystallisation of methyl or ethyl esters of palm oil,
palm kernel oil and palm oil products, or
[0014] (5) crystallisation of methyl or ethyl esters of palm oil,
palm kernel oil and palm oil products, followed by fractional
distillation.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The present invention discloses methyl oleate (more than 98%
purity) and methyl linoleate (more than 98% purity) respectively or
a mixture containing high proportion of methyl oleate and methyl
linoleate (.tau. 90%) as a premium grade palm diesel. This premium
grade palm diesel can solve the pour point problem encountered when
palm oil methyl esters (consisting of C16 (45%), C18 (5%), C18:1
(39%) and C18:2 (10%)) are used in cold climate countries.
[0016] Methyl oleate, a fraction from palm oil methyl esters not
only exhibits good fuel properties just like the palm oil methyl
esters but also possesses low pour point of -18.theta.C. Methyl
linoleate exhibits pour point of -39.theta.C. This pour point is
very much lower compared to that of palm oil methyl esters (mixture
of C16, C18, C18:1 and C18:2). Thus, it can be used in cold climate
countries or during low operational temperatures. Similarly, it is
found that a mixture containing high proportion of methyl oleate
and methyl linoleate e.g. C14 (0.5%), C16 (5.0%), C18:1 (83.6%) and
C18:2 (11.0%) also exhibits low pour point of -21.theta.C. Whereas,
a methyl esters mixture of C14 (0.5%), C16 (5.7%), C18 (2.0%),
C18:1 (79.0%) and C18:2 (12.7%) exhibits pour point of -15.theta.C.
Methyl esters mixture of C14 (0.6%), C16 (6.3%), C18 (2.9%), C18:1
(74.6%) and C18:2 (15.7%) exhibits pour point of -12.theta.C. While
methyl esters mixture containing C14 (0.7%), C16 (6.7%), C18
(0.4%), C18:1 (75.5%) and C18:2 (16.7%) exhibits pour point of
-9.theta.C.
[0017] While the normal grade palm diesel would be the normal palm
oil methyl or ethyl esters, (45% C16, 5% C18, 39% C18:1 and 10%
C18:2), which exhibit pour point of +15.theta.C. This grade is not
suitable to be utilised in cold countries as it will solidify in
cold countries. Whereas C18, C18:1 and C18:2 mixed methyl or ethyl
esters that has a pour point of below -15.theta.C can be used in
cold climate countries.
[0018] The said mixture of methyl or ethyl esters exhibiting low
pour point can be produced, particularly but not exclusively via
(1) esterification of C18, C18:1 and C18:2 mixed fatty acids with
methanol and ethanol, or (2) fractional distillation of methyl or
ethyl esters from palm oil, palm kernel oil and palm oil products,
or (3) fractional distillation of methyl or ethyl esters of palm
oil, palm kernel oil and palm oil products, followed by
crytallisation, or (4) crystallisation of methyl or ethyl esters of
palm oil, palm kernel oil and palm oil products, or (5)
crystallisation of methyl or ethyl esters of palm oil, palm kernel
oil or palm oil products, followed by fractional distillation.
[0019] All methyl and ethyl esters mentioned could be obtained
through fractionation of methyl or ethyl ester of palm oil, palm
kernel oil and palm oil products or via esterification of the
respective fatty acids and methanol or ethanol respectively. The
acid-catalysed esterification of respective fatty acids (or mixed
fatty acids cut) and methanol or ethanol can be carried out to
yield the methyl or ethyl esters since fatty acids can be easily
obtained from fat splitting of palm oil. The C16 methyl or ethyl
esters and C18, C18:1 and C18:2 mixed methyl or ethyl esters can be
obtained through fractionation of methyl or ethyl esters of palm
oil, palm kernel oil and palm oil products, either by fractional
distillation or crystallisation or integrated fractional
distillation and crystallisation under controlled pressure and
temperature i.e. fractional distillation followed by
crystallisation or crystallisation followed by fractional
distillation. The C16 methyl esters fraction can be sold for
oleochemical uses such as feedstock for .DELTA.-sulphonated methyl
esters and high quality white soap while the C18, C18:1 and C18:2
mixed methyl or ethyl esters fraction having pour point that meets
the requirement (-15.theta.C to -21.theta.C) can be used in
temperate countries as biofuel. Other than deriving low pour point
palm diesel from palm oil methyl esters, the processes disclosed in
this invention could be adapted to the production of low pour point
palm diesel from palm kernel oil methyl or ethyl esters. Palm
kernel oil methyl esters consists of C6 (0.3%), C8 (4.4%), C10
(3.7%), C12 (48.3%), C14 (15.6%), C16 (7.8%), C18 (2.0%), C18:1
(15.1%) and C18:2 (2.9%). Integrated processes of fractional
distillation and crystallisation, i.e. fractional followed by
crystallisation or crystallisation distillation followed by
fractional distillation would lead to the production of low pour
point palm diesel.
[0020] Crystallisation of methyl or ethyl esters of palm oil, palm
kernel oil and palm oil products can be done by
[0021] (a) dry fractionation
[0022] (b) solvent fractionation.
[0023] under gradual cooling and controlled conditions.
[0024] Saturated methyl or ethyl esters i.e. methyl or ethyl
palmitate and methyl or ethyl stearate can be fractionated from the
unsaturated methyl or ethyl esters i.e. methyl or ethyl oleate and
methyl or ethyl linoleate via dry fractionation (crystallisation).
Fine crystals formed when palm oil methyl or ethyl esters were
subjected to gradual cooling and slow agitation. Upon subjecting
the suspension of fine crystals to membrane filtration, C16 and C18
methyl or ethyl esters with purity of at least 80% can be produced.
By subjecting the resultant fraction to second stage fractionation,
the purity of the saturated methyl or ethyl esters can be further
enhanced. The same approach can be used for the filtrate obtained
from the first stage fractionation to produce the high
compositional of methyl or ethyl oleate (C18:1 methyl esters) and
methyl or ethyl linoleate (C18:2 methyl esters) with minimal methyl
or ethyl palmitate (C16 methyl or ethyl esters) and methyl or ethyl
stearate (C18 methyl or ethyl esters) in order to produce palm
diesel with low pour point. The residue fractions obtained from
several second stage crystallisation of filtrate rich in
unsaturated methyl or ethyl esters are preferred to be combined and
subjected to further crystallisation. While the filtrate fractions
obtained from several second stage crystallisation of residue rich
in saturated methyl or ethyl esters are also preferred to be
combined and subjected to further crystallisation. Thus, in this
manner, there will be no loss of the starting material (methyl or
ethyl esters of palm oil, palm kernel oil and palm oil
products).
[0025] The present invention also discloses another route of
fractionation, i.e. via solvent fractionation. Saturated methyl
esters ie. methyl or ethyl palmitate and methyl or ethyl stearate
can be efficiently fractionated from unsaturated methyl or ethyl
esters ie. methyl or ethyl oleate and methyl or ethyl linoleate.
Methanol, ethanol and isopropanol have been proven to be excellent
choices of solvent for the crystallisation of saturated methyl or
ethyl esters from the unsaturated methyl or ethyl esters. The
typical composition of unsaturated methyl esters fraction obtained
is 1-2% methyl myristate, 4-6% methyl palmitate, 0-1% methyl
stearate, 70-72% methyl oleate, 20-22% methyl linoleate and 0-1%
methyl arachidate. While the saturated methyl esters fraction
consists of 0-0.4% methyl myristate, 86-89% methyl palmitate, 6-7%
methyl stearate, 3-5% methyl oleate, 1-2% methyl linoleate and 0-2%
of methyl arachidate.
[0026] One aspect of the present invention discloses the
composition of methyl or ethyl esters (C8, C0, C12, C14, C16, C18,
C18:1 and C18:2 methyl or ethyl esters) carbon chain length of and
the respective pour point. The pour point depends very much on the
percentage of methyl or ethyl esters of different chain length. It
is found that a mixture containing high proportion of methyl oleate
and methyl linoleate e.g. C14 (0.5%), C16 (5.0%), C18:1 (83.6%) and
C18:2 (11.0%) also exhibits low pour point of -21.theta.C. Whereas,
a methyl esters mixture of C14 (0.5%), C16 (5.7%), C18 (2.0%),
C18:1 (79.0%) and C18:2 (12.7%) exhibits pour point of -15.theta.C.
Methyl esters mixture of C14 (0.6%), C16 (6.3%), C18 (2.9%), C18:1
(74.6%) and C18:2 (15.7%) exhibits pour point of -12.theta.C. While
methyl esters mixture containing C14 (0.7%), C16 (6.7%), C18
(0.4%), C18:1 (75.5%) and C18:2 (16.7%) exhibits pour point of
-9.theta.C. Low pour point palm diesel can also be achieved if and
only if the mixture of methyl or ethyl esters of palm oil, palm
kernel oil and palm oil products has (1) less than 10% of total
saturated methyl or ethyl esters i.e. C14 methyl or ethyl ester,
C16 methyl or ethyl ester and C18 methyl or ethyl ester (2) at
least 90% C18:1 and C18:2 mixed methyl or ethyl ester.
[0027] Besides exhibiting low pour point, the C18, C18:1 and C18:2
mixed methyl or ethyl esters also exhibit other fuel properties
(viscosity, flash point, sulfur content, gross heat of combustion,
conradson carbon residue, specific gravity and boiling point)
similar to those of petroleum diesel, thus indicating its
suitability as a diesel substitute. The overall performance of the
C18 mixed methyl esters is also being tested in stationery engines
and field trials.
[0028] The following examples further illustrate the present
invention.
EXAMPLE 1
[0029] The premium grade palm diesel has pour point .delta.
15.theta.C, depending on its composition.
[0030] (a) Mixture of methyl esters, namely methyl myristate
(0.5%), methyl palmitate (4.9%), methyl oleate (83.6%) and methyl
linoleate (11.0%) exhibit low pour point of -21.theta.C. This
methyl esters mixture was obtained via acid-catalysed direct
esterification of technical grade of oleic acid (with purity
.vertline. 80%) with methanol.
[0031] (b) Mixture of methyl esters synthesized with 0.6% methyl
myristate, 5.7% of methyl palmitate, 2.0% methyl stearate, 78.97%
methyl oleate and 12.69% methyl linoleate has a pour point of
-15.theta.C. Therefore, these mixtures of C18, C18:1 and C18:2
methyl esters can be utilised in temperate countries when the
operational temperature dropped to below 15.theta.C.
EXAMPLE 2
[0032] Mixtures of C18, C18:1 and C18:2 methyl esters can also be
obtained through vacuum fractional distillation of palm oil methyl
esters (consisting of C16 (45%), C18 (5%), C18:1 (39%) and C18:2
(10%)). At pressure of 30 Pa, 90% methyl palmitate was fractionated
out at 139.theta.C followed by mixtures of C18, C18:1 and C18:2
methyl esters at 154-156.degree. C.
EXAMPLE 3
[0033] Another possible route to produce different grade of palm
diesel is by using partial vacuum fractionation of palm oil methyl
esters. Under pressure of 25 Pa and temperature ranging between
145.theta.C to 154.theta.C, mixture of methyl esters consisting
6.0% methyl palmitate, 8.5% methyl stearate, 69.5% methyl oleate
and 16.1% methyl linoleate was obtained. This fraction of methyl
esters exhibits pour point of below 0.theta.C.
EXAMPLE 4
[0034] Crystallisation of palm oil methyl esters was carried out
using one part of palm oil methyl esters in two part of methanol.
Bulk of C16 methyl esters crystallised out from palm oil methyl
esters when cooled down from 22.theta.C to -12.theta.C in two
stages. The remaining unsaturated (C18:1 and C18:2) mixed methyl
esters has a pour point of -33.theta.C. This unsaturated mixed
methyl esters consist 1.64% of methyl laurate, 5.04% methyl
palmitate, 0.65% methyl stearate, 72.85% methyl oleate, 19.38%
methyl linoleate and 0.45% methyl arachidate.
EXAMPLE 5
[0035] Crystallisation of palm oil methyl esters was carried out
using one part of palm oil methyl esters in two parts of methanol.
The mixture was cooled to +5.theta.C in 30 minutes. The mixture was
filtered using suction filtration to collect both the residue and
filtrate. The filtrate was then subjected to second stage
crystallisation, where it was cooled to -11.theta.C in 2.5 hours.
The filtrate after this stage consists high percentage of
unsaturated methyl esters, e.g. 70-72% C18:1 methyl esters and
20-22% C18:2 methyl esters. The filtrate collected from the stage
crystallisation was washed with some cold methanol (+5.theta.C) in
order to get high percentage of saturated methyl esters. The
filtrate exhibits pour point of -12.theta.C.
EXAMPLE 6
[0036] Solvent crystallisation of distilled palm oil methyl esters
using methanol as solvent can also be carried out by one step
chilling. The mixture was cooled to -9.theta.C in 2 hours. After
suction filtration, the filtrate collected contains 68-69% C18:1
methyl ester and 18-19% C18:2 methyl ester.
EXAMPLE 7
[0037] Crystallisation of palm oil methyl esters was carried out
using one part of palm oil methyl esters in two part of ethanol. In
the first stage of crystallisation, the mixture was cooled to
+3.theta.C in 30 minutes. While in the second stage of
crystallisation, the filtrate was cooled to -9.theta.C in 2.5
hours. After filtration, filtrate with high percentage of
unsaturated methyl esters, e.g. 63-64% C18:1 methyl ester and
15-16% C18:2 methyl esters was obtained.
EXAMPLE 8
[0038] Crystallisation of palm oil methyl esters was carried out
using one part of palm oil methyl esters in three part of methanol.
In the first stage of crytallisation, the mixture was cooled to
+2.theta.C in 1 hour. While in the second crystallisation, the
filtrate was then cooled to -12.theta.C for 2.5 hours. After
filtration to remove the residue, high percentage of unsaturated
methyl esters, e.g. 71-72% C18:1 methyl ester and 18-19% C18:2
methyl esters. Meanwhile, the residue collected from the first and
second stage crystallisation was washed with cold methanol in order
to get high purity of saturated methyl esters, e.g. 91-92% C16
methyl ester and 6-7% C18:0 methyl esters.
EXAMPLE 9
[0039] Crystallisation was carried out for the fractions obtained
from partial fractional distillation. A fraction consists of 3.41%
C16 methyl esters, 8.82% C18 methyl esters, 71.56% C18:1 methyl
esters and 16.21% C18:2 methyl esters was cooled down from
+26.theta.C to 0.theta.C in 30 minutes crystallisation in a water
bath of -5.theta.C. One part of methanol was used for one part of
the mentioned fraction was used. The residue consists of 5.58% C16
methyl esters, 83.94% C18 methyl esters, 5.83% C18:1 methyl esters,
1.16% C18:2 methyl esters and 3.48% C20 methyl esters.
EXAMPLE 10
[0040] Crystallisation of a fraction consisting 0.34% C12 methyl
esters, 2.21% C14 methyl esters, 64.51% C16 methyl esters, 2.04%
C18 methyl esters, 24.66% C18:1 methyl esters and 6.23% C18:2
methyl esters was carried out in a water bath at -5.theta.C,
cooling from +26.theta.C to +5.theta.C in 20 minutes. This process
produced residue which consists 0.89% C14 methyl esters, 91.45% C16
methyl esters, 1.56% C18 methyl esters, 5.15% C18:1 methyl esters
and 0.96% C18:2 methyl esters. One part of methanol was used for
one part of fraction.
EXAMPLE 11
[0041] Crystallisation of a fraction consisting 0.34% C12 methyl
esters, 2.21% C14 methyl esters, 64.51% C16 methyl esters, 2.04%
C18 methyl esters, 24.66% C18:1 methyl esters and 6.23% C18:2
methyl esters was carried out in a water bath at -5.theta.C,
cooling from +26.theta.C to +5.theta.C in 3 minutes. This process
produced residue with composition of 0.94% C14 methyl esters,
91.37% C16 methyl esters, 2.09% C18 methyl esters, 4.74% C18:1
methyl esters and 0.87% C18:2 methyl esters. Two part of methanol
was used for one part of fraction. Meanwhile, the filtrate consists
of 10.68% C16 methyl esters, 4.50% C18 methyl esters, 68.59% C18:1
methyl esters, 15.57% C18:2 methyl esters and 0.68% C20 methyl
esters.
EXAMPLE 12
[0042] Dry crystallisation of a fraction consisting 0.34% C12
methyl esters, 2.21% C14 methyl esters, 64.51% C16 methyl esters,
2.04% C18 methyl esters, 24.66% C18:1 methyl esters and 6.23% C18:2
methyl esters was carried out in a water bath at -5.dwnarw.C,
cooling from +25.theta.C to +10.theta.C in 5 minutes. This process
produced residue with composition of 1.51% C14 methyl esters,
82.97% C16 methyl esters, 2.05% C18 methyl esters, 11.38% C18:1
methyl esters and 2.08% C18:2 methyl esters. Meanwhile, the
filtrate consists of 10.46% C16 methyl esters, 2.84% C18 methyl
esters, 70.22% C18:1 methyl esters, 16.09% C18:2 methyl esters and
0.8% C20 methyl esters.
EXAMPLE 13
[0043] Dry fractionation of palm oil methyl esters consists of C14
(0.95%), C16 (45.01%), C18 (4.09%), C18:1 (39.91%), C18:2 (9.75%)
and C20 (0.29%) was carried out under gradual cooling from
+40.theta.C to +8.theta.C in 15 hours and held at that temperature
for 3 hours. Upon membrane filtration of the crystal suspension,
the resultant residue consists of C14 (0.8%), C16 (86.0%), C18
(1.8%), C18:1 (8.8%) and C18:2 (2.6%), i.e. 88.6% saturated methyl
esters and 11.6% unsaturated methyl esters. While the filtrate
consists of C12 (0.7%), C14 (2.0%), C16 (25.1%), C18 (2.4%), C18:1
(53.6%) and C18:2 (15.9%) and C20 (0.4%), i.e. 30.5% saturated
methyl esters and 69.5% unsaturated methyl esters.
EXAMPLE 14
[0044] Dry fractionation of palm oil methyl esters consists of C14
(1.0%), C16 (45.0%), C18 (4.1%), C18:1 (39.9%), C18:2 (9.8%) and
C20 (0.3%) was carried out under gradual cooling from +40.theta.C
to +9.theta.C in 6 hours and held at that temperature for 12 hours.
Upon membrane filtration of the crystal suspension, the resultant
residue consists of C14 (0.9%), C16 (79.7%), C18 (1.9%), C18:1
(13.5%) and C18:2 (4.0%), i.e. 82.6% saturated methyl esters and
17.4% unsaturated methyl esters. While the filtrate consists of C12
(0.7%), C14 (2.1%), C16 (25.1%), C18 (2.4%), C18:1 (53.2%) and
C18:2 (16.0%) and C20 (0.4%), i.e. 30.8% saturated methyl esters
and 69.3% unsaturated methyl esters.
EXAMPLE 15
[0045] Second stage of dry crystallisation on the residue or the
saturated methyl esters was carried out using the residue obtained
from a process as described in Example 14 to improve the purity.
The filtrate which consists of C14 (0.9%), C16 (79.7%), C18 (1.9%),
C18:1 (13.5%) and C18:2 (4.0%), i.e. 82.6% saturated methyl esters
and 17.4% unsaturated methyl esters was subjected to gradual
cooling from +40.theta.C to +24.theta.C in 4.5 hours and held at
that temperature for 2.5 hours. Upon membrane filtration of the
crystal suspension, the resultant residue consists of C14 (0.3%),
C16 (95.2%), C18 (1.0%), C18:1 (2.7%) and C18:2 (0.8%), i.e. 96.5%
saturated methyl esters and 3.5% unsaturated methyl esters. While
the filtrate consists of C12 (0.3%), C14 (2.1%), C16 (69.4%), C18
(2.4%), C18:1 (20.6%) and C18:2 (6.0%), i.e. 73.4% saturated methyl
esters and 26.6% unsaturated methyl esters.
EXAMPLE 16
[0046] Dry fractionation of palm oil methyl esters consists of C14
(0.95%), C16 (45.01%), C18 (4.09%), C18:1 (39.91%), C18:2 (9.75%)
and C20 (0.29%) was carried out under gradual cooling from
+40.theta.C to +12.theta.C in 15 hours and held at that temperature
for 3 hours. Upon membrane filtration of the crystal suspension,
the resultant residue consists of C14 (0.7%), C16 (87.9%), C18
(1.6%), C18:1 (7.7%) and C18:2 (2.2%), i.e. 90.2% saturated methyl
esters and 9.8% unsaturated methyl esters. While the filtrate
consists of C12 (0.7%), C14 (1.9%), C16 (32.1%), C18 (2.4%), C18:1
(48.3%) and C18:2 (14.3%) and C20 (0.3%), i.e. 37.4% saturated
methyl esters and 62.6% unsaturated methyl esters. The filtrate was
subjected to a second stage dry crystallisation.
EXAMPLE 17
[0047] Second stage of dry crystallisation on the filtrate or the
unsaturated methyl esters was carried out using the filtrate
obtained from a process as described in Example 16 to improve the
purity. The filtrate which consists of C12 (0.7%), C14 (1.9%), C16
(32.1%), C18 (2.4%), C18:1 (48.3%) and C18:2 (14.3%) and C20
(0.3%), i.e. 37.4% saturated methyl esters and 62.6% unsaturated
methyl esters was subjected to gradual cooling from +40.theta.C to
+2.theta.C in 13 hours and held at that temperature for 6 hours.
Upon membrane filtration of the crystal suspension, the resultant
residue consists of C12 (1.0%), C14 (1.6%), C16 (54.0%), C18
(2.8%), C18:1 (31.3%) and C18:2 (9.3%), i.e. 59.4% saturated methyl
esters and 40.6% unsaturated methyl esters. While the filtrate
consists of C12 (0.8%), C14 (2.2%), C16 (17.8%), C18 (2.3%), C18:1
(58.9%) and C18:2 (17.7%) and C20 (0.4%), i.e. 73.4% saturated
methyl esters and 26.6% unsaturated methyl esters.
EXAMPLE 18
[0048] One mole of technical grade of oleic acid (with fatty acid
composition of 0.5% C14, 5.5% C16, 80.2% C18:1 and 13.8% of C18:2)
was esterified with six moles of methanol at 160.theta.C. A 0.5
weight percent of concentrated sulphuric acid was used as catalyst.
After 4.5 hours of reaction, the crude product was water washed
until the decanted aqueous layer was neutral. The dried product was
subjected to second stage of esterification (re-esterification).
The esterification steps were similar to the first stage
esterification, except 0.3 weight percent of catalyst was used. The
resultant methyl esters from the first and second stage
esterification exhibit pour point of -15.theta.C and -21.theta.C
respectively.
EXAMPLE 19
[0049] A fraction obtained from crystallisation with composition of
C14 (0.3%), C16 (95.2%), C18 (1.0%), C18:1 (2.7%) and C18:2 (0.8%),
i.e. 96.5% saturated methyl esters and 3.5% unsaturated methyl
esters was subjected to further fractional distillation. This
integrated process managed to C16 methyl esters with purity more
than 97%.
EXAMPLE 20
[0050] The C18, C18:1 and C18:2 mixed esters not only has low pour
point but also exhibit good fuel properties that are comparable to
palm oil methyl esters. TABLE 1 the tabulated fatty acid
composition of the mixed methyl esters and its respective fuel
properties are tabulated in the TABLE 2.
1TABLE 1 Fatty Acid Composition (as % methyl esters) of C18, C18:1
and C18:2 Mixed Methyl Esters. Fatty Acid Composition Methyl Esters
(as % methyl esters) Methyl Palmitate (C16) 4.2 Methyl Stearate
(C18) 0.4 Methyl Oleate (C18:1) 81.6 Methyl Linoleate (C18:2)
13.8
[0051]
2TABLE 2 Fuel Properties of C18, C18:1 and C18:2 Methyl Esters,
Palm Diesel and Malaysian Diesel Methyl Esters (C18, C18:1 &
Malaysian Test Palm Diesel C18:2 mixture) Diesel* Specific Gravity
0.8700 0.8803 0.8330 ASTM D1290 @ 74.5 .theta.F @ 60 .theta.F @ 60
.theta.F Sulfur Content (% wt) 0.04 0.04 0.10 IP242 Viscosity @ 40
.theta.C (cSt) 4.5 4.5 4.0 ASTM D445 Pour Point (.theta.C) 16.0
-15.0 15.0 ASTM D97 Gross Heat of Combustion 40,335 39,160 45,800
(kJ/kg) ASTM D2332 Flash Point (.theta.C) 174 153.0 98 ASTM D93
Conradson Carbon Residue 0.02 0.1 0.14 (% wt) ASTM D198
Distillation (.theta.C) 324.0 282.2 228 Initial Boiling Point ASTM
D86 *sample obtained from PETRONAS petrol kiosk
* * * * *