U.S. patent application number 11/614618 was filed with the patent office on 2007-07-05 for processes of producing biodiesel and biodiesel produced therefrom.
Invention is credited to Scott Bloomer, Inmok Lee, Jerry L. Mayfield, Lisa M. Pfalzgraf, Leif Solheim.
Application Number | 20070151146 11/614618 |
Document ID | / |
Family ID | 38218738 |
Filed Date | 2007-07-05 |
United States Patent
Application |
20070151146 |
Kind Code |
A1 |
Lee; Inmok ; et al. |
July 5, 2007 |
Processes of Producing Biodiesel and Biodiesel Produced
Therefrom
Abstract
The present disclosure discloses processes for treating,
producing, or producing and treating biodiesel. Products produced
with the various processes of the present invention are also
disclosed.
Inventors: |
Lee; Inmok; (Decatur,
IL) ; Mayfield; Jerry L.; (Decatur, IL) ;
Pfalzgraf; Lisa M.; (Decatur, IL) ; Solheim;
Leif; (Decatur, IL) ; Bloomer; Scott;
(Decatur, IL) |
Correspondence
Address: |
ARCHER DANIELS MIDLAND COMPANY
4666 FARIES PARKWAY
DECATUR
IL
62526
US
|
Family ID: |
38218738 |
Appl. No.: |
11/614618 |
Filed: |
December 21, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60754979 |
Dec 29, 2005 |
|
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60831575 |
Jul 17, 2006 |
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Current U.S.
Class: |
44/605 |
Current CPC
Class: |
Y02E 50/13 20130101;
C07C 67/56 20130101; C10G 2300/1011 20130101; C10L 1/026 20130101;
C11C 1/08 20130101; C07C 67/58 20130101; Y02E 50/10 20130101; C11C
3/003 20130101; Y02P 30/20 20151101; C07C 67/56 20130101; C07C
69/24 20130101; C07C 67/56 20130101; C07C 69/52 20130101; C07C
67/58 20130101; C07C 69/24 20130101 |
Class at
Publication: |
044/605 |
International
Class: |
C10L 5/00 20060101
C10L005/00 |
Claims
1-118. (canceled)
119. A process for reducing the filter blocking tendency of
biodiesel, comprising: placing the biodiesel in contact with a
solid or liquid, the solid or liquid comprising a compound capable
of reducing the filter blocking tendency of biodiesel.
120. The process of claim 119, wherein placing the biodiesel in
contact with the solid or liquid comprises mixing the solid or
liquid with the biodiesel, and further comprising separating the
solid or liquid from the biodiesel.
121. The process of claim 119, wherein placing the biodiesel in
contact with the solid or liquid comprises passing the biodiesel
through a bed of the solid or the liquid.
122. The process of claim 119, wherein steryl glycosides are
removed from the biodiesel.
123. The process of claim 119, wherein the solid or liquid is
selected from the group consisting of adsorbents, filter aids,
boric acid, soap, sucrose, sugar, glucose, sodium chloride, citric
acid, magnesium silicate, clay, diatomaceous earth, lecithin,
granular clay, granular glucose, granular sugar, protein, textured
vegetable protein, carbon, cellulose, solutions comprising boric
acid, silica hydrogel, beta-glucosidases, and combinations of any
thereof.
124. The process of claim 119, further comprising subjecting the
biodiesel to a filter blocking test comprising: determining whether
a pre-selected volume of the biodiesel passes through a filter
within a pre-selected time; wherein the pre-selected volume of the
biodiesel passes through the filter before the pre-selected time is
reached, giving the biodiesel a passing test result; wherein the
pre-selected time is reached before the pre-selected volume of the
biodiesel passes through the filter, giving the biodiesel a failing
test result.
125. The process of claim 119, further comprising subjecting the
biodiesel to a degumming step.
126. The process of claim 119, further comprising filtering the
biodiesel through a filter aid selected from the group consisting
of diatomaceous earth, sugar, and a combination thereof.
127. The process of claim 119, further comprising: incubating the
biodiesel at between 40.degree. F. and 70.degree. F.; and filtering
the incubated biodiesel.
128. The process of claim 127, wherein filtering the incubated
biodiesel comprises placing the biodiesel in contact with a
compound selected from the group consisting of diatomaceous earth,
carbon, cellulose, and combinations of any thereof.
129. The process of claim 119, wherein the solid of the liquid is
contacted with the biodiesel as a body feed.
130. The process of claim 119, further comprising forming a precoat
of the solid or the liquid on a filter.
131. The process of claim 127, further comprising subjecting the
filtered biodiesel to a test selected from the group consisting of
ASTM D2068, a modified ASTM D6217 and a combination thereof.
132. The process of claim 131, further comprising incubating the
filtered biodiesel for a second incubation period prior to
subjecting the filtered biodiesel to the test, thus decreasing the
content of steryl glycosides in the filtered biodiesel.
133. The process of claim 119, further comprising, wherein placing
the biodiesel in contact with the solid or the liquid comprises
filtering the biodiesel through the solid comprising a bed of
water-soluble solid bed material; and dissolving the water-soluble
solid bed material in water to remove the water- soluble solid bed
material, thus producing a composition enriched in steryl
glycosides.
134. The process of claim 133, further comprising washing the bed
with a solvent.
135. The process of claim 119, further comprising subjecting the
biodiesel to a filter blocking test comprising: determining whether
a pre-selected volume of the biodiesel passes through a filter
before a pre-selected pressure is placed on the filter from the
biodiesel; wherein the pre-selected volume of the biodiesel passes
through the filter before the pre-selected pressure is reached,
giving the biodiesel a passing test result; wherein the
pre-selected pressure is reached before the pre-selected volume of
the biodiesel passes through the filter, giving the biodiesel a
failing test result.
136. The process of claim 119, wherein the biodiesel comprises a
detectable level of steryl glycosides that is less than 70 ppm.
137. The process of claim 119, further comprising: incubating the
biodiesel, a filter cake obtained from the biodiesel production, a
final filter cake of the biodiesel production, and combinations of
any thereof with a first solvent to obtain a solid component and a
liquid component; separating the solid component from the liquid
component; washing the solid component with a second solvent; and
removing the second solvent from the first solvent, thus obtaining
a purified steryl glycoside.
138. A process for treating biodiesel comprising: placing biodiesel
in contact with a compound capable of removing steryl glycosides
from the biodiesel.
139. The process of claim 138, further comprising: separating the
biodiesel from the compound capable of removing the steryl
glycosides; and mixing the biodiesel separated from the compound
capable of removing steryl glycosides with a fuel selected from the
group consisting of a petroleum based diesel fuel, a biodiesel not
placed in contact the compound capable of removing steryl
glycosides, ethanol, and any combinations thereof.
140. The process of claim 138, further comprising: wherein the
compound is selected from the group consisting of adsorbents,
filter aids, boric acid, soap, sucrose, sugar, glucose, sodium
chloride, citric acid, magnesium silicate, clay, diatomaceous
earth, lecithin, granular clay, granular glucose, granular sugar,
protein, textured vegetable protein, carbon, cellulose, solutions
comprising boric acid, and combinations of any thereof; and
separating the compound from the biodiesel.
141. The process of claim 140, wherein the compound is separated
from the biodiesel by a process selected from the group consisting
of filtration, centrifugation, and combinations of any thereof.
142. The process of claim 140, wherein the biodiesel is derived
from an oil that is selected from the group consisting of vegetable
oil, canola oil, safflower oil, sunflower oil, nasturtium seed oil,
mustard seed oil, olive oil, sesame oil, soybean oil, corn oil,
peanut oil, cottonseed oil, rice bran oil, babassu nut oil, castor
oil, palm oil, palm kernel oil, rapeseed oil, low erucic acid
rapeseed oil, palm kernel oil, lupin oil, jatropha oil, coconut
oil, flaxseed oil, evening primrose oil, jojoba oil, tallow, beef
tallow, butter, chicken fat, lard, dairy butterfat, shea butter,
biodiesel, used frying oil, oil miscella, used cooking oil, yellow
trap grease, hydrogenated oils, derivatives of the oils, fractions
of the oils, conjugated derivatives of the oils, and mixtures of
any thereof.
143. A process for removing monoacylglycerols from a fatty acid
methyl ester containing material, comprising: placing a compound
selected from the group consisting of magnesium silicate, granular
sugar, steryl glycosides, and any combination thereof in contact
with a fatty acid containing material; and separating the compound
from the fatty acid containing material.
144. The process of claim 143, wherein the compound is separated
from the fatty acid containing material by a process selected from
the group consisting of filtration, centrifugation, and
combinations of any thereof.
145. The process of claim 143, wherein the fatty acid containing
material is selected from the group consisting of vegetable oil,
canola oil, safflower oil, sunflower oil, nasturtium seed oil,
mustard seed oil, olive oil, sesame oil, soybean oil, corn oil,
peanut oil, cottonseed oil, rice bran oil, babassu nut oil, castor
oil, palm oil, palm kernel oil, rapeseed oil, low erucic acid
rapeseed oil, palm kernel oil, lupin oil, jatropha oil, coconut
oil, flaxseed oil, evening primrose oil, jojoba oil, camelina oil,
tallow, beef tallow, butter, chicken fat, lard, dairy butterfat,
shea butter, biodiesel, used frying oil, oil miscella, used cooking
oil, yellow trap grease, hydrogenated oils, derivatives of the
oils, fractions of the oils, conjugated derivatives of the oils,
and mixtures of any thereof.
146. The process of claim 143, further comprising: adjusting a
temperature of the fatty acid containing material; mixing a solid
capable of reducing the content of monoacylglycerols with the fatty
acid containing material; and separating the solid from the fatty
acid containing material.
147. A process for treating biodiesel, comprising: placing the
biodiesel in contact with a solid or liquid capable of improving
the result of a cold test of biodiesel.
148. A process for producing biodiesel, comprising: mixing a fatty
acid containing material with an alcohol, thus producing a
biodiesel precursor mixture; subjecting the biodiesel precursor
mixture to a condition that allows biodiesel to form, the condition
being selected from the group consisting of time, an increased
temperature, an increased pressure, the presence of a catalyst and
any combination thereof; isolating the biodiesel; and treating the
biodiesel with silica hydrogel.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/754,979, filed Dec. 29, 2005, and provisional
U.S. patent application 60/831,575, filed Jul. 17, 2006, each of
the contents of the entirety of which are incorporated by this
reference.
TECHNICAL FIELD
[0002] The present disclosure relates generally to biodiesel and
processes for producing biodiesel.
BACKGROUND
[0003] Biodiesel is manufactured from animal or vegetable oils. The
preferred feedstock for producing biodiesel in Europe is rapeseed
(i.e., canola) oil. In North America, some canola oil is used to
produce biodiesel, but soybean oil is also used as a feedstock in
producing biodiesel. Biodiesel is used as an additive to
petroleum-derived diesel fuel or as a substitute for
petroleum-derived diesel fuel in diesel (compression-ignition)
engines. Biodiesel usually comprises fatty acid methyl esters
(FAME) or fatty acid ethyl esters.
[0004] The use of biodiesel in cold climates may require special
considerations due to the tendency of precipitates to form in the
biodiesel at temperatures of 0.degree. C. and below. These
precipitates impair the flow characteristics of biodiesel.
SUMMARY OF THE INVENTION
[0005] The present invention discloses processes for producing
biodiesel as well as biodiesel produced therefrom.
[0006] In one embodiment, a process for treating biodiesel
comprises placing biodiesel in contact with a compound capable of
removing steryl glycosides from the biodiesel.
[0007] In another embodiment, a process for treating biodiesel
comprises placing biodiesel in contact with a compound capable of
removing monoacylglycerols from the biodiesel.
[0008] In another embodiment, a process for treating biodiesel
comprises reducing the filter blocking tendency of the
biodiesel.
[0009] In another embodiment, a process for removing steryl
glycosides from a fatty acid methyl ester containing material
comprises placing a compound selected from the group consisting of
adsorbents, filter aids, boric acid, soap, sucrose, sugar, glucose,
carbon, activated carbon, cellulose, sodium chloride, citric acid,
magnesium silicate, clay, diatomaceous earth, lecithin, granular
clay, granular glucose, granular sugar, protein, textured vegetable
protein, solutions of boric acid, silica hydrogel, and combinations
of any thereof in contact with a fatty acid containing material,
and separating the compound from the fatty acid containing
material.
[0010] In another embodiment, a process for removing
monoacylglycerols from a fatty acid methyl ester containing
material or biodiesel comprises placing a compound selected from
the group consisting of magnesium silicate, steryl glycosides, and
a combination thereof in contact with the fatty acid methyl ester
containing material or the biodiesel.
[0011] In another embodiment, the biodiesel is separated from the
compounds capable of removing monoacylglycerols from the biodiesel.
In an embodiment, the compound is separated from the fatty acid
containing material by a process selected from the group consisting
of filtration, centrifugation, and combinations of any thereof.
[0012] In another embodiment, the biodiesel separated from the
compounds capable of removing monoacylglycerols from the biodiesel
is mixed with a petroleum based diesel fuel, a biodiesel not placed
in contact with the compound capable of removing the
monoacylglycerols, ethanol, or any combinations thereof.
[0013] In an additional embodiment, a process for reducing the
filter blocking tendency of biodiesel includes placing the
biodiesel in contact with a solid or liquid, wherein the solid or
liquid comprises a compound capable of reducing the filter blocking
tendency of biodiesel.
[0014] In yet a further embodiment, a process for producing
biodiesel includes mixing a fatty acid containing material and an
alcohol, thus producing a biodiesel precursor mixture. The
biodiesel precursor mixture is subjected to a condition that allows
biodiesel to form, wherein the condition is selected from the group
consisting of time, an increased temperature, an increased
pressure, the presence of a catalyst and any combination thereof.
The process further includes isolating the biodiesel and removing
steryl glycosides from the biodiesel, wherein the steryl glycosides
are removed from the biodiesel at a temperature of less than
125.degree. C.
[0015] In yet a further embodiment, a process for producing
biodiesel includes mixing a fatty acid containing material and an
alcohol, thus producing a biodiesel precursor mixture. The
biodiesel precursor mixture is subjected to a condition that allows
biodiesel to form, wherein the condition is selected from the group
consisting of time, an increased temperature, an increased
pressure, the presence of a catalyst and any combination thereof.
The process further includes isolating the biodiesel and removing
monoacylglycerols from the biodiesel, wherein the monoacylglycerols
are removed from the biodiesel at a temperature of less than
125.degree. C. In an embodiment, the biodiesel is of soy
origin.
[0016] In yet another embodiment, a biodiesel production plant
comprises a compound capable of removing steryl glycosides from the
biodiesel, and a conduit operably configured to place biodiesel in
contact with the compound capable of removing steryl glycosides
from the biodiesel.
[0017] In yet another embodiment, a biodiesel production plant
comprises a compound capable of removing monoacylglycerols from the
biodiesel, and a conduit operably configured to place biodiesel in
contact with the compound capable of removing steryl
monoacylglycerols from the biodiesel.
[0018] In another embodiment, an apparatus configured to treat
biodiesel includes a reservoir for containing a biodiesel having an
initial filter blocking tendency value, a compound capable of
removing steryl glycosides from the biodiesel, and a conduit
operatively configured to place the biodiesel in contact with the
compound capable of removing steryl glycosides from the
biodiesel.
[0019] In another embodiment, an apparatus configured to treat
biodiesel includes a reservoir for containing a biodiesel having an
initial filter blocking tendency value, a compound capable of
removing monoacylglycerols from the biodiesel, and a conduit
operatively configured to place the biodiesel in contact with the
compound capable of removing monoacylglycerols from the
biodiesel.
[0020] In a further embodiment, a process for preparing a
composition enriched in steryl glycosides includes filtering a
steryl glycoside containing composition through a bed of
water-soluble solid bed material, and dissolving the water-soluble
solid bed material in water to remove the water-soluble solid bed
material, wherein a composition enriched in steryl glycosides is
obtained.
[0021] In one embodiment, a steryl glycoside composition comprising
steryl glycosides or a biodiesel origin is disclosed.
[0022] In a further embodiment, a biodiesel includes a detectable
level of steryl glycosides, wherein a level of steryl glycosides in
the biodiesel is less than 70 ppm.
[0023] In still a further embodiment, a biodiesel comprises a
detectable level of steryl glycosides, monoacylglycerols,
diacylglycerols, triacylglycerols, or any combinations thereof,
wherein the biodiesel passes a filter blocking test. The filter
blocking test includes determining whether a pre-selected volume of
the product passes through a filter before a pre-selected pressure
is placed on the filter from the product. When the pre-selected
volume of the product passes through the filter before the
pre-selected pressure is reached, the biodiesel passes the filter
blocking test. When the pre-selected pressure is reached before the
pre-selected volume of the product passes through the filter, the
biodiesel fails the filter blocking test.
[0024] In another embodiment, a biodiesel comprises a detectable
level of steryl glycosides, monoacylglycerols, diacylglycerols,
triacylglycerols, or any combination thereof, and passes a filter
blocking test. The filter blocking test comprises: adjusting a
temperature of a sample of the biodiesel to 15 to 25 degrees
Celsius; shaking the sample for 120 seconds; allowing the sample to
stand on a vibration-free surface for 300 seconds; placing 320
milliliters of the sample into a fuel reservoir beaker of a
Normalab Analis NBF 240 instrument; ensuring that the temperature
of the sample is maintained at the 15 to 25 degrees Celsius;
placing a pump suction pipe of the Normalab Analis NBF 240
instrument into the fuel reservoir beaker; operating a pump of the
Normalab Analis NBF 240 instrument until biodiesel flows into a
collection beaker; pouring any fuel from the collection beaker into
the fuel reservoir beaker; placing a fresh filter on a filter unit
of the Normalab Analis NBF 240 instrument; attaching the assembled
filter unit to the Normalab Analis NBF 240 instrument with a Luer
fitting; starting the pump of the Normalab Analis NBF 240
instrument; reading a pressure gauge after 20 seconds; and pumping
the sample at a flow rate of 20 ml/minute until 300 milliliters
have passed through the filter or until the pressure gauge reaches
105 kPa. The biodiesel passes the filter blocking test when 300
milliliters of the sample passes through the filter before 105 kPa
is reached, and fails the filter blocking test when 105 kPa is
reached before 300 milliliters of the sample passes through the
sample.
[0025] In another embodiment, a biodiesel comprises a detectable
level of steryl glycosides, monoacylglycerols, diacylglycerols,
triacylglycerols, or combinations of any thereof, and passes a
filter blocking test. The filter blocking test comprises: filtering
30 milliliters of biodiesel through a 1.6 um GF/A filter having 47
mm diameter under a 21-25 inch Hg vacuum. The biodiesel passes the
filter blocking test when the entire sample of 300 ml passes
through the filter in 6 minutes or less.
[0026] In a further exemplary embodiment, a process for treating
biodiesel comprises placing biodiesel in contact with a compound
selected from the group consisting of adsorbents, filter aids,
boric acid, soap, sucrose, sugar, glucose, carbon, activated
carbon, cellulose, sodium chloride, citric acid, magnesium
silicate, clay, diatomaceous earth, lecithin, granular clay,
granular glucose, granular sugar, protein, textured vegetable
protein, steryl glycosides, and combinations of any thereof, and
separating the biodiesel from the compound.
[0027] In another embodiment, the fatty acid containing material
from which steryl glycosides, monoacylglycerols, or combinations
thereof are separated is selected from the group consisting of
vegetable oil, canola oil, safflower oil, sunflower oil, nasturtium
seed oil, mustard seed oil, olive oil, sesame oil, soybean oil,
corn oil, peanut oil, cottonseed oil, rice bran oil, babassu nut
oil, castor oil, palm oil, palm kernel oil, rapeseed oil, low
erucic acid rapeseed oil, lupin oil, jatropha oil, coconut oil,
flaxseed oil, evening primrose oil, jojoba oil, camelina oil,
tallow, beef tallow, butter, chicken fat, lard, dairy butterfat,
shea butter, biodiesel, used frying oil, oil miscella, used cooking
oil, yellow trap grease, hydrogenated oils, derivatives of the
oils, fractions of the oils, conjugated derivatives of the oils,
and mixtures of any thereof.
[0028] In an embodiment, biodiesel is mixed with a solid or liquid
capable of improving the cold test results of a biodiesel. In an
embodiment, the solid or liquid is mixed with the biodiesel at a
first temperature and the solid or liquid is separated from the
biodiesel; the biodiesel is adjusted to have a second temperature,
and the biodiesel is subjected to a cold test.
[0029] In a further embodiment, biodiesel is incubated at a first
temperature, filtered through a compound, incubated at a second
temperature, and subjected to a filter blocking test. In a further
embodiment, the biodiesel is incubated at 40.degree. F., filtered
through a compound selected from the group consisting of
diatomaceous earth and cellulose, incubated at a second
temperature, and subjected to a filter blocking test.
DETAILED DESCRIPTION OF THE INVENTION
[0030] Biodiesel comprises ethyl or methyl esters of fatty acids of
biological origin. Starting materials for the production of
biodiesel include, but are not limited to, materials containing
fatty acids. These materials include, without limitation,
triacylglycerols, diacylglycerols, monoacylglycerols,
phospholipids, esters, free fatty acids or any combinations
thereof. The biodiesel is produced by incubating the material
including the fatty acids with a short chain alcohol in the
presence of heat, pressure, a catalyst or combinations of any
thereof to produce fatty acid esters of the short chain alcohols.
In industrial practice, biodiesel may undergo a final simple
filtration step, such as through a polishing "sock" filter, to
remove any remaining fine particulate matter. Such a filter step
may comprise a first screen having 10 micron pore size and a second
screen of 1 micron pore size. These fatty acid esters of the short
chain alcohols may be used as supplements to or replacements for
diesel fuel in compression ignition engines.
[0031] The fatty acids used to produce the biodiesel may originate
from a wide variety of natural sources including, but not limited
to, vegetable oil, canola oil, safflower oil, sunflower oil,
nasturtium seed oil, mustard seed oil, olive oil, sesame oil,
soybean oil, corn oil, peanut oil, cottonseed oil, rice bran oil,
babassu nut oil, castor oil, palm oil, palm oil, rapeseed oil, low
erucic acid rapeseed oil, palm kernel oil, lupin oil, jatropha oil,
coconut oil, flaxseed oil, evening primrose oil, jojoba oil,
camelina oil, tallow, beef tallow, butter, chicken fat, lard, dairy
butterfat, shea butter, biodiesel, used frying oil, oil miscella,
used cooking oil, yellow trap grease, hydrogenated oils,
derivatives of the oils, fractions of the oils, conjugated
derivatives of the oils, and mixtures of any thereof.
[0032] Some components of biodiesel such as, for example, esters of
saturated fatty acids may cause the development of crystals when
the biodiesel is subjected to cold conditions. For instance, the
presence of methyl ester containing saturated fatty acids,
monoacylglycerol (monoglyceride) containing saturated fatty acids,
diacylglycerol (diglyceride) containing saturated fatty acids (as
low as 0.1 wt %), and unsaponifiable matter (at levels of 3%) may
cause cold-flow problems in biodiesel. As one example,
monoacylglycerols containing saturated fatty acids may form
crystals in the biodiesel and may cause flow problems or fuel
blockages in biodiesel fuel systems. In another example, a fuel
blockage in a biodiesel fuel system may be caused by the cooling of
esters of saturated fatty acids in the biodiesel. These fuel
blockages may occur when vehicles powered by biodiesel or a blend
of diesel and biodiesel are exposed to cold conditions. These
problems caused by the crystals or cooled esters of saturated fatty
acids may be rectified by heating and, thus, melting the
crystallized materials or heating the cooled esters of saturated
fatty acids. The heat may be applied by towing the affected vehicle
to a warm garage, or applying a heat source such as a heat blower
to the fuel lines and systems of the vehicle. Under these
conditions, fuel flow is restored when the crystallized material
melts, and esters of saturated fatty acids pass into the combustion
chamber for burning.
[0033] The formation of precipitates at temperatures of 0.degree.
C. and below resulted in the development of tests to measure the
impact of cold temperatures on biodiesel. For instance, in the USA,
the cloud point of the biodiesel is determined with the ASTM method
D 2500. In Europe, the cold filter plugging point of biodiesel of
heating oil is determined with a test designated EN 116. These
tests are used to ensure that the biodiesel falls within the
required standards. However, these tests do not account for the
presence of precipitates which may form in soy biodiesel without
exposure to cold temperatures. These precipitates can cause fuel
blockage such as restriction or blockage of fuel filters, which is
distinct from the problem of the precipitation of esters of
saturated fatty acids caused by exposure to cold.
[0034] In one embodiment, the fatty acid containing materials or
products used to produce the biodiesel may also be subjected to
processes to separate solid material, such as esters of saturated
fatty acids, from liquid material, such as esters of unsaturated
fatty acids and polyunsaturated fatty acids to remove the solid
material and prevent any potential blocking issues.
[0035] Biodiesel has been scrutinized because an amorphous
cloud-like substance may develop in the biodiesel when stored at
room temperature in addition to the flow problems that occur at
cold temperatures. This amorphous cloud-like substance may cause
clogging of fuel filters. The resulting constriction or stoppage of
fuel flow is not related to cold temperatures and requires the
frequent changing of filters, which is costly and inconvenient. The
amorphous cloud-like substance that is observed at room temperature
is not crystallized esters of fatty acids, such as saturated methyl
esters or mono-, di-, or triacylglycerols of saturated fatty
acids.
[0036] In another embodiment, it was surprisingly discovered that
the amorphous cloud-like substance included steryl glycosides.
These steryl glycosides in biodiesel increase the filter blocking
tendency of biodiesel without exposure of the biodiesel to cold
temperatures.
[0037] In a further embodiment, crystals formed in biodiesel at
room temperature were observed under the microscope. The crystals
appeared as particles of about 10-15 microns in size. The crystals
were associated together in loose, amorphous, gel-like agglomerates
of various sizes. After incubating biodiesel containing the
crystals with water for a few hours, the morphology of the
individual particles and the agglomerates changed, indicating the
presence of surface-active material. These crystals were recovered
and identified as steryl glycosides. The steryl glycosides include
sterol glucosides, steryl glucosides, or sterol glycosides.
[0038] The steryl glycoside crystals may also contain fatty acid
methyl esters (FAME), which may be entrapped or bound. The presence
of steryl glycosides in biodiesel can be detected by the
development or presence of a visible opacity or "haze" in the
biodiesel at room temperature without a microscope. In another
embodiment, it was determined that the amount of haze visible in
room-temperature biodiesel (.about.25.degree. C.) is related to the
tendency of biodiesel to fail a filter blocking test designed to
test the flow of fuel at 15-25.degree. C.
[0039] The steryl glycosides present in biodiesel comprise a sterol
group linked to a carbohydrate at the hydroxyl moiety of the
sterol. The steryl glycosides may also contain a fatty acid
esterified to a hydroxyl group of the carbohydrate moiety; these
compounds may be described as acylated steryl glycosides. It was
also found that the ability of the steryl glycosides to increase
the filter blocking occurred regardless of the presence of meltable
crystals of glycerol esters of saturated fatty acids or the
presence of a fatty acid moiety.
[0040] Acylated steryl glycosides are naturally occurring compounds
found in plants. The acylated steryl glycosides comprise a sterol
group bound to a carbohydrate having a fatty acid acylated to the
primary hydroxyl group of the carbohydrate moiety of a steryl
glycoside. One of the acylated steryl glycosides present in soybean
extracts is the 6'-linoleoyl-beta-D-glucoside of beta sitosterol
present at about 47%. In plants, other fatty acids or monobasic
carboxylic acids, such as palmitic acid, oleic acid, stearic acid,
linoleic acid, and linolenic acid may also be acylated to the
carbohydrate moiety through an ester bond. The acylated steryl
glycosides are two to ten times more abundant in plants than the
(non-acylated) steryl glycosides. Steryl glycosides, also known as
sterolins, are present as monoglycosides in the oil from which
biodiesel is synthesized, although a few diglycosides also exist. A
common sugar in steryl glycosides is D-glucose, which is joined to
the sterol via the 3-beta-hydroxy group by means of an equatorial
or beta-glucoside bond. Other monosaccharides that may be found in
steryl glycosides include mannose, galactose, arabinose and
xylose.
[0041] The amount of steryl glycosides in crude soybean oil is
higher than in corn oil or sunflower oil. Crude soy oil may contain
about 2300 ppm steryl glycosides, while crude oils from corn and
sunflower contain about 500 ppm and 300 ppm, respectively. Steryl
glycosides are enriched in gums produced by degumming soy, corn and
sunflower oils, and present in concentrations of about 19300 ppm,
5400 ppm, and 16800 ppm, respectively, and can be expected to be
similarly enriched in soapstock and acid oils from vegetable
oils.
[0042] In oil refining, gums resulting from degumming crude oil and
soapstock resulting from alkali refining of crude oil or degummed
oil are often further processed to recover entrained oil and fatty
acids. This process may be carried out by hydrolysis of the gums or
soapstock to increase the content of free fatty acids. Hydrolysis
may be carried out by the application of steam and alkali or acid.
Acid is sometimes used because the acid facilitates separation of a
free fatty acid phase from a water-rich phase. The free fatty acid
phase is a product called "acid oil". Acid oil may be used as a
feedstock for biodiesel synthesis. The glycosides in gums and
soapstock can also be present in the acid oil, so biodiesel made
from acid oil can have high levels of steryl glycosides and result
in the flow problems described herein.
[0043] The steryl glycosides in the biodiesel cause problems for
flow of the biodiesel. Even low levels of the steryl glycosides
(i.e., 10-90 ppm) in the biodiesel can form aggregates with fatty
acid methyl esters that may appear as a visible cloud. These
aggregates can accelerate filter plugging at any temperature, not
just cold temperatures, due to the high melting point of steryl
glycosides (i.e., 240.degree. C.). At room temperatures, the steryl
glycosides can aggregate and plug filters used for biodiesel fuel.
At cold temperatures, the cold-flow problems caused by alkyl esters
of saturated fatty acids such as monoacylglycerols may be
compounded by the presence of the steryl glycosides.
[0044] The steryl glycosides not only cause problems for flow of
the biodiesel, but can also hamper the production of biodiesel. For
instance, since biodiesel is often centrifuged as a final polishing
step in the manufacture of biodiesel, the centrifuges used for the
final purification step can become filled with steryl
glycoside-rich solids, resulting in costly process interruptions
and shut-downs to clean the centrifuges. In addition, since
biodiesel is often subjected to a final polishing filtration step,
such as by passage through a sock filter, the sock filters can
become filled or blinded (occluded) with steryl glycoside-rich
solids, also resulting in costly process interruptions and
shut-downs to clean and/or replace the filter material.
[0045] The formation of steryl glycoside crystals in the biodiesel
may be exacerbated in the presence of trace amounts of water. This
is because the steryl glycosides, visible as haze in biodiesel, may
grow in volume when the steryl glycosides are placed in contact
with water. The grown or expanded steryl glycoside crystals make
the crystals even more prone to causing fuel restriction or
blockage.
[0046] Unlike esters of saturated fatty acids, steryl glycosides
cannot be practically removed by melting or exposure to heat since
the melting point of steryl glycosides is 240.degree. C. This means
that the steryl glycosides cannot be practically heated and melted
to allow the steryl glycosides to pass through a filter into a
combustion chamber for burning. Further, in the event the steryl
glycosides were to reach the fuel injectors of a diesel engine, the
steryl glycosides may accumulate and form a refractory gum-like
material that would require disassembly and cleaning of the
injectors, thus increasing the operating expense of the diesel
engine.
[0047] Further, since the steryl glycosides are insoluble in most
solvents, with the exception of pyridine, dioxane and
dimethylformamide, the cleaning of components having accumulated
steryl glycosides is problematic. This is because pyridine, dioxane
and dimethylformamide are not found in the usual diesel repair
facility, and their health hazards make these solvents unsafe for
use outside of a fume hood. Consequently, the build-up of the
steryl glycosides on diesel engine components would require
labor-intense abrasive cleaning or expensive replacement of fuel
injectors and other fouled components.
[0048] In another embodiment, processes for removing steryl
glycosides from biodiesel or oils are disclosed. The steryl
glycosides are removed by placing the biodiesel or oil in contact
with a compound capable of removing the steryl glycosides from the
biodiesel or oil. By removing the steryl glycosides from the
biodiesel, the biodiesel has a reduced tendency to have a retarded
flow or block filters.
[0049] In another embodiment, a biodiesel placed in contact with a
compound capable of removing steryl glycosides (i.e., treated
biodiesel) has a reduced amount of steryl glycosides as compared to
a biodiesel not placed in contact with a compound capable of
removing steryl glycosides (i.e., untreated biodiesel). The treated
biodiesel also has a reduced filter blocking tendency as compared
to the untreated biodiesel. The treated biodiesel may have a FBT
value of less than 1.414 as determined by ATSM method D 2068. In an
embodiment, the treated biodiesel may pass a modified ASTM D6217
method.
[0050] In another embodiment, biodiesel incubated or stored at
temperatures below ambient temperature, has a reduced Filter
Blocking Tendency, as determined by ASTM method D 2068.
[0051] In another embodiment, processes for removing
monoacylglycerols from biodiesel or oils are disclosed. The
monoacylglycerols are removed by placing the biodiesel or oil in
contact with a compound capable of removing the monoacylglycerols
from the biodiesel or oil. By removing the monoacylglycerols from
the biodiesel, the biodiesel has a reduced tendency to have a
retarded flow or block filters when the biodiesel or oil is used in
combination with an engine.
[0052] In another embodiment, a biodiesel placed in contact with a
compound capable of removing monoacylglycerols (i.e., treated
biodiesel) has a reduced amount of monoacylglycerols as compared to
a biodiesel not placed in contact with a compound capable of
removing monoacylglycerols (i.e., untreated biodiesel). The treated
biodiesel also has a reduced filter blocking tendency as compared
to the untreated biodiesel. The treated biodiesel may have a FBT
value of less than 1.414 as determined by ATSM method D 2068. In an
embodiment, the treated biodiesel may pass a modified ASTM D6217
method.
[0053] Since conventional tests for ascertaining the consequences
of cooling biodiesel, such as pour point or cold filter plugging
point, are not useful in detecting the presence of steryl
glycosides, it was surprisingly found that IP 387 and the ATSM
method (D 2068, "Standard Test Method for Filter Blocking Tendency
of Distillate Fuel Oils") provide measurements of filter blocking
capabilities in biodiesel that has not been cooled.
[0054] The tests for measuring filter blocking capabilities herein
described are carried out with a Normalab Analis (Lintot, France)
NBF 240 instrument. A sample (that is substantially free of
undissolved water) is passed through a specified glass-fiber filter
medium at 20 ml/minute. The pressure difference across the filter
is monitored, and the volume of fuel passing through the filter
medium within a prescribed pressure drop is measured. According to
the test, the filter blocking tendency is defined on a linear scale
through a discontinuity point of 105 kPa/300 ml. This provides a
dimensionless unit which is independent of the point of test
cessation. The test ceases when the pressure difference across a
specified filter reaches 105 kPa or when 300 ml of biodiesel passes
through the filter, whichever is reached first. The results are
reported as a volume or pressure at the point of cessation. A
sample passes the test if a 300 ml volume can pass through a filter
having a 1.6 micron particle retention and 13 mm diameter (such as
Millipore Cat. No. XX30 012 00 from Millipore Corp. or Grade GF/A
(FBT) from Whatman (Cat. No. 1820 8013)) without developing a
pressure equal to or greater than 105 kPa. A sample fails the test
if the pressure reaches 105 kPa before 300 ml of biodiesel is
passes through the filter.
[0055] In this embodiment, filter blocking tendency (FBT) can be
described in one of the following ways: the pressure drop across a
1.6 .mu.m pore size glass fiber filter when 300 mL of fuel is
passed at a rate of 20 mL/min, or the volume of fuel passed when a
pressure of 105 kPa (15 psi) is reached. The latter method is used
when less than 300 mL passes at a rate of 20 mL/min before the
pressure exceeds 105 kPa. A sample of the fuel to be tested is
passed at a constant rate of flow (20 mL/min) through a glass fiber
filter medium. The pressure drop across the filter is monitored
during the passage of a fixed volume of test fuel. If a prescribed
maximum pressure drop is reached before the total volume of fuel is
filtered, the actual volume of fuel filtered at the time of maximum
pressure drop is recorded.
[0056] Before the test, the temperature of biodiesel being sampled
is adjusted to about 15 to 25.degree. C. The biodiesel is shaken
vigorously for about 120 seconds (plus or minus 5 seconds), and
allowed to stand on a vibration-free surface for about 300 seconds.
A sample of about 320 mL, plus or minus 5 mL, is placed into the
fuel reservoir beaker of the Normalab Analis NBF 240 instrument and
the temperature is checked to ensure that it is within the range of
about 15 to 25.degree. C. (the actual temperature is recorded). The
pump suction pipe of the instrument is placed into the fuel
reservoir beaker. The pump is run until biodiesel flows from the
fitting to which the filter unit is attached into the collection
beaker. The pump is stopped, and any fuel from the collection
container is poured back into the fuel reservoir beaker. The filter
unit is assembled with a fresh filter, and the assembled filter
unit is attached to the instrument through a Luer fitting. The pump
and stopwatch are started, and after about 20 seconds, the pressure
gauge reading is recorded. If the pressure gauge reading falls in
the range of about 7 to 21 kPa, pumping is continued at 20
ml/minute and the pressure gauge is monitored continuously. If the
pressure rises to 105 kPa, the pump is stopped immediately and the
volume of liquid that passed through the filter at that point is
reported as v. If the pressure does not rise to 105 kPa after 300
mL has passed through the filter, the highest pressure reached in
the test is reported as P.
[0057] Filter blocking tendency (FBT) is calculated using one of
the following equations, depending on whether a value was obtained
for v or P. FBT= 1+(P/105).sup.2=(Square root of (1+(P/105).sup.2),
or (1+(P/105).sup.2).sup.1/2 FBT= 1+(300/v).sup.2=(Square root of
(1+(300/v).sup.2), or (1+(300/v).sup.2)/.sup.1/2 P is the maximum
pressure reading obtained for 300 mL of biodiesel to pass through
the filter, in kilopascals; and V is the volume of fuel passed at a
pressure reading of 105 kPa, in milliliters.
[0058] FBT is expressed as a dimensionless number to the nearest
0.01. A FBT value close to 1 indicates good flow characteristics,
and an FBT value of 1.414 or greater indicates poor flow and
indicates that the fuel failed the FBT test. As the minimum test
volume is 20 ml, liquids which exceed 105 kPa pressure in 20 ml or
less are assigned the greatest FBT value that can be determined
(i.e., 15.03).
[0059] An alternative method of testing biodiesel is a modified
ASTM 6217 test. The modified ASTM 6217 test is carried out as
follows: biodiesel (300 ml) is filtered through a 1.6 um GF/A
filter having 47 mm diameter under a 21-25 inch Hg vacuum. The
entire volume of 300 ml of the biodiesel must pass through the
filter in an predetermined amount of time, such as 30 minutes, 15
minutes, 12 minutes, 10 minutes, 9 minutes, 8 minutes, 7 minutes, 6
minutes, 5, minutes, 4 minutes, 3 minutes, 2 minutes, 1 minute, or
fractions thereof.
[0060] In order to produce biodiesel having an acceptable FBT value
or pass a modified ASTM 6217 test, the biodiesel may be treated to
obtain an acceptable FBT value or pass a modified ASTM 6217 test
using methods of the present invention. Some conventional
treatments to the biodiesel do not produce an acceptable FBT value
or biodiesel that passes a modified ASTM 6217 test. For instance,
biodiesel that is water washed to remove water-soluble impurities
does not remove the steryl glycosides since the steryl glycosides
are poorly soluble or insoluble in water. Thus, biodiesel treated
by water washing contained 34 ppm steryl glycosides and failed the
FBT test by exceeding 105 kPa pressure in less than 20 mL of the
biodiesel.
[0061] Another conventional treatment of biodiesel is distillation.
Although the distillation of the biodiesel may produce a biodiesel
having an acceptable FBT value or that may pass a modified ASTM
6217 test, the distillation procedure is not economically
acceptable. Thus, even though a commercial sample of biodiesel
subjected to a distillation procedure contained no detectable
steryl glycosides and had an FBT value of 1.01, the distillation
procedure is costly. For instance, purification by distillation is
expensive and inefficient. Further, the entire finished biodiesel
product must be distilled by conventional means such as over a
column or on a wiped film evaporator, necessitating costly inputs
of energy to heat and cool the biodiesel. In addition, as biodiesel
contains large amounts of heat-sensitive compounds, such as esters
of olefinic fatty acids, the elevated temperatures required for
distillation will accelerate the breakdown of the biodiesel, such
as by lipid oxidation, leading to reduced storage stability of the
distilled biodiesel. Alternatively, costly measures to store the
biodiesel, such as the addition of antioxidants or blanketing with
an inert gas, may be required.
[0062] In various embodiments described herein, an improved
biodiesel having a reduced filter blocking tendency, as defined by
test IP 387 (and ASTM Method D 2068, "Standard Test Method for
Filter Blocking Tendency of Distillate Fuel Oils") is prepared
using the processes herein. By treating biodiesel with solid
compounds, a treated biodiesel having a reduced filter blocking
tendency than the starting biodiesel is produced. The improved
biodiesel has a decreased amount of steryl glycosides. In some
embodiments, the improved biodiesel has a decreased amount of
monoacylglycerols. Further, it is desired that the improved
biodiesel is able to flow at temperatures of 0.degree. C. and
below. Suitable solid compounds that may be used include, but are
not limited to, adsorbents, filter aids, water-soluble solids,
water-soluble bed materials, and any combinations thereof.
[0063] In one embodiment, a bed of solid bed material is associated
with a filter and used to treat biodiesel by passing the biodiesel
through the bed, thus, removing steryl glycosides from the
biodiesel.
[0064] In an embodiment, a bed of solid bed material is associated
with a filter and used to treat biodiesel by passing the biodiesel
through the bed, thus, removing monoacylglycerols. In an
embodiment, the compound can be applied to a filter as a precoat,
wherein a layer of the compound is deposited on a filter and
biodiesel is filtered by passing through the filter and the layer
of the precoat. To apply a precoat, the desired quantity of
compound is slurried in a small amount of biodiesel and the slurry
is passed over or through the filter, such as a filter screen. The
biodiesel passes thought the filter, leaving a thin layer of the
compound on the screen for subsequent use in filtering biodiesel.
In an embodiment, the compound can be applied to biodiesel as a
body feed, wherein the compound is mixed with biodiesel and the
mixture of the compound and the biodiesel is passed through a
filter. In another embodiment, the compound mixed with biodiesel as
a body feed may be passed through a filter and a layer of
precoat.
[0065] In another embodiment, solid compounds may be added to
biodiesel and slurried before removal of the solid compounds by
passing the biodiesel/solid compound slurry through a filter. Solid
bed materials that may be used include, but are not limited to,
water-soluble solid bed materials. When water-soluble solid bed
materials are used to treat the biodiesel, the solid bed material
can be washed with solvent to remove any residual biodiesel. The
water soluble solid bed material may also be dissolved in water to
obtain a material enriched in steryl glycosides. Thus, in another
embodiment, a process for purifying or obtaining steryl glycosides
is disclosed.
[0066] In an additional embodiment, indicia are associated with
biodiesel treated by the methods or processes of the present
disclosure to inform the purchaser, distributor, blender or
consumer of treated biodiesel that the treated biodiesel passes a
filter blocking test or a modified ASTM 6217 test. In another
embodiment, the indicia may disclose the results of a filter
blocking tendency test result or a modified ASTM 6217 test. In
another embodiment, the indicia may inform the purchaser, blender,
distributor or consumer that the biodiesel has been treated to
reduce the content of steryl glycosides and/or monoacylglycerols in
the biodiesel. In yet another embodiment, indicia are associated
with the treated biodiesel to provide or disclose the content of
steryl glycosides.
[0067] In an embodiment, a period of incubation of biodiesel prior
to filtration may be employed. In an embodiment, the temperature of
incubation or storage may be below the manufacturing temperature.
The duration of incubation prior to filtration may be 15 minutes,
30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours,
12 hours, 18 hours, 24 hours, 2 days, 3, days, 4 days, 5 days, 6
days, 1 week, 2 weeks, 3 weeks, 4 weeks, 1 month, 2 months, 3
months, 4 months, 5 months, 6 months, or fractions of any thereof.
In an embodiment, the temperature may be zero degrees Fahrenheit,
10 degrees Fahrenheit , 20 degrees Fahrenheit, 30 degrees
Fahrenheit, 40 degrees Fahrenheit, 50 degrees Fahrenheit, 60
degrees Fahrenheit, 70 degrees Fahrenheit, 80 degrees Fahrenheit,
90 degrees Fahrenheit, 100 degrees Fahrenheit, 110 degrees
Fahrenheit, 120 degrees Fahrenheit, or fractions of any thereof.
Following the incubation, the biodiesel may be filtered such as
through a polishing filter, a bag filter, a sock filter, a dewaxing
filter or any combination thereof. In an embodiment, filtration may
employ the use of a compound in the form of a body feed, a precoat,
or combinations thereof. In another embodiment, biodiesel my be
incubated or stored for a second period prior to being subjected to
a test to determine filterability, such as ASTM Method D 2068 or a
modified ASTM D6217 test.
[0068] The invention is further explained by use of the following
illustrative examples.
EXAMPLE 1
[0069] In one embodiment, biodiesel was tested to see if the
biodiesel has an acceptable FBT value. Commercially manufactured
rapeseed biodiesel that was subjected to a final polishing
filtration step through a final sock filter having 1 micron pore
size at 14250 kg/hour was obtained. Filter blocking tests were
performed on the rapeseed biodiesel using a Normalab Analis
(Lintot, France) NBF 240 instrument according to IP 387 (and ASTM
Method D 2068, Standard Test Method for Filter Blocking Tendency of
Distillate Fuel Oils, ASTM International. The ASTM standards may be
obtained from the ASTM website at www.astm.org. The biodiesel flow
through the polishing sock filters was unimpeded and the FBT value
of the finished biodiesel was 1.02 (maximum pressure reached in
filtration of 300 ml biodiesel was 21 kPa).
[0070] In another embodiment, fatty acids recovered from a
glycerol-rich heavy phase of biodiesel manufactured by the process
of U.S. Pat. No. 5,354,878 (which is hereby incorporated in its
entirety by reference) were used as feedstock to synthesize
biodiesel using hydrochloric acid as a catalyst. These fatty acids
are referred to as "acid oil". The following amounts of reactants
were used to synthesize the biodiesel: 100 parts fatty acid, 100
parts methanol, 3 parts hydrochloric acid, and 180 minutes of
incubation with heat and stirring in a 1000 liter vessel. The
resulting biodiesel (780 kg) was blended into the 14250/kg/hour
flow of rapeseed biodiesel going to the filters over the course of
2 hours (390 kg/hour). The FBT of the blended biodiesel increased
steadily until it reached a peak of 1.69 and failed the FBT test by
reaching 105 kPa pressure after filtering only 220 ml. Solid
material on the final bag filter having 1 micron pore size was
tested by thin-layer chromatography and a spot having a retention
factor equal to a steryl glycoside reference was observed. Both
Nuclear Magnetic Resonance and gas chromatography with mass
spectroscopy determined that the solid material on the final bag
filter having 1 micron pore size contained sterol and sugar
structures.
EXAMPLE 2
[0071] Commercially manufactured soy biodiesel which had not been
subjected to simple final filtration through a polishing filter was
obtained. This unfiltered soy biodiesel was subjected to filtration
treatments through compounds, wherein the biodiesel was placed in
contact with a compound for removing steryl glycosides from the
biodiesel. The compounds in this example included granular glucose,
granular sugar, diatomaceous earth, and granular clay. A Buchner
funnel was fitted with #1 filter paper (3.8 cm diameter, 11.3
cm.sup.2 filter area, >11 micron particle retention) and beds of
the various solid bed materials (i.e., compounds for removing the
steryl glycosides) were prepared. The amount of time required to
pass 50, 100, 150 and 200 ml of room temperature biodiesel through
the filter was determined (Table 1). Studies were carried out in
duplicate.
[0072] Filtration volumes and times for biodiesel passed through
compounds. Diatomaceous earth (DE) was FW20 from Eagle Picher,
Phoenix, AZ. Granular clay was Agsorb 30/60 LVM-GA from OilDri,
Chicago, Ill. TABLE-US-00001 TABLE 1 Filtration volumes and timers
for biodiesel passed through compounds. Diatomaceous earth (DE) was
FW20 from Eagle Picher, Phoenix, AZ. Granular clay was Agsorb 30/60
LVM-GA from OilDri, Chicago, IL. Filter cake Filtration time (sec)
thickness Filter volume (ml) 50 100 150 200 (mm) Control #1 paper
12 67 181 250 -- Granular Glucose 15 67 130 220 15 (15 g) Granular
Sugar 4 15 28 42 12 (15 g) DE (5 g) 31 82 137 196 11 Granular Clay
(10 g) 42 110 192 295 14
[0073] The content of steryl glycosides in the unfiltered biodiesel
was estimated to be 70-90 ppm obtained by ascertaining the increase
in weight that occurred with the granular sugar used as a solid bed
material. The filter paper with no additional solid bed material
was blinded or coated quickly with a gummy deposit, resulting in
slow filtration (long filtration time). After filtering biodiesel
through filter paper with no additional solid bed material at room
temperature, the steryl glycosides content of the filtered (i.e.,
treated) biodiesel was 50 ppm. Granular glucose, granular sugar and
diatomaceous earth (DE) provided shorter filtration times. The
filtration time obtained with granular clay was longer than the
other solid bed materials. The shortest filtration time, and thus
the fastest flow, was obtained with granulated sugar, while a
constant filtration rate was obtained with diatomaceous earth
DE.
EXAMPLE 3
[0074] Magnesium silicate (Magnesol R30, Dallas Group, Whitehouse,
N.J.) was tested as a "body feed" for treating biodiesel having a
steryl glycoside content of 174 ppm and visible haze. Unfiltered
biodiesel (180 g) was slurried at room temperature or at 60.degree.
C. with Magnesol R30 (added as "body feed" to the biodiesel) for 10
minutes. The slurry was filtered through Whatman #1 filter paper at
room temperature. The steryl glycoside content in biodiesel before
and after Magnesol treatment and filtration was measured. The
filtered biodiesel was also subjected to a Cold test (AOCS Official
Method Cc 11-53) to evaluate the reduction of haziness. A procedure
of the cold test is found in "Official Methods and Recommended
Practices of the AOCS", Fifth Edition, Second Printing (2004)
American Oil Chemists' Society, Champaign, Ill., which is
incorporated herein in its entirety by this reference. For the cold
test, 4 oz. clear sample bottles were filled with biodiesel before
immersion in an ice water bath maintained at 0.degree. C. The
sample bottles were removed from the ice water bath every hour to
examine the appearance of the biodiesel for haziness. To pass the
test, the biodiesel samples should be completely clear and
brilliant. TABLE-US-00002 TABLE 2 Filtration of biodiesel with
Magnesol R30 at room temperature (RT). SG R30, R30, Filter
Appearance content Cold test % g time, sec. at RT (ppm) @ 4 hours
0.2 0.36 84 clear 34 fail 1.2 2.16 202 clear 35 pass
[0075] TABLE-US-00003 TABLE 3 Filtration of biodiesel with Magnesol
R30 at 60.degree. C. SG 30, Filter Appearance content Cold test %
30, g time, sec. at RT (PPM) @ 6 hours .2 .36 33 clear 74
borderline .2 .16 108 clear 41 pass
[0076] All levels of Magnesol R30 treatment were effective at
reducing the appearance of haze at room temperature and 60.degree.
C. The appearance of haze or lack of appearance of haze at room
temperature in biodiesel treated at room temperature and treated at
60.degree. C. was used as a qualitative assessment of possible
steryl glycoside content. Room-temperature magnesium silicate
treatment was more effective at reducing the quantity of steryl
glycosides in biodiesel than treatment at 60.degree. C., and also
produced a biodiesel which passed a cold test at 4 hours (Tables 2
and 3). However, the ability of the biodiesel to pass the cold test
after filtration at room temperature was unrelated to the steryl
glycosides content of the biodiesel, indicating that the cold test
was not actually measuring steryl glycoside content, but rather
measuring some other component (i.e., possibly the crystals rich in
saturated fatty acid ester which develop under cold
conditions).
[0077] Samples of biodiesel filtered with 1.2% Magnesol at room
temperature and 60.degree. C. were analyzed to determine the
effectiveness of Magnesol treatment at reducing the content of
monoacylglycerols and the results are presented in Table 4.
TABLE-US-00004 TABLE 4 Monoacylglycerol reduction by treatment with
Magnesol R30. Monoacylglycerols (%) No Magnesol (control) 0.72 1.2%
Magnesol at room 0.61 temperature 1.2% Magnesol at 60.degree. C.
0.59
[0078] Cooling the biodiesel was not required to reduce the content
of monoacylglycerols. A reduction of 15% was effected at room
temperature and a reduction of 17% was effected at 60.degree.
C.
EXAMPLE 4
[0079] Water-soluble compounds (i.e., sugar, sodium chloride, and
citric acid) were compared with DE for their ability to remove
steryl glycoside from biodiesel and produce improved biodiesel.
Commercial biodiesel (600 g) having a steryl glycoside content of
174 ppm was filtered through the water-soluble solid bed materials
(14 grams of granular sugar, sodium chloride (NaCl) or citric acid)
or diatomaceous earth (DE, 5 grams) on a Whatman #1 filter paper
(3.4 cm diameter) under vacuum. Residual biodiesel was removed from
the sugar, sodium chloride, and citric acid filter cakes by washing
with .about.100 ml hexane and hot water (.about.70.degree. C., 200
ml), which was used to dissolve the solid bed materials and recover
the steryl glycosides. The recovered steryl glycosides remaining on
the filter paper were dried in a 70.degree. C. oven overnight.
TABLE-US-00005 TABLE 5 Steryl glycoside content and filter blocking
tendencies of biodiesel treated with solid bed materials. Solid bed
FBT SG SG material value (ppm) reduction (%) None 15.03 174 --
(control) Granular 1.14 22 87.3 sugar NaCl 1.05 22 87.3 Citric acid
1.05 22 87.3 DE 1.01 39 77.6
[0080] Excellent Filter Blocking Tendency (FBT) values and
reduction of steryl glycosides of from 77.6% to 87.3% were obtained
with the solid bed materials tested (Table 5).
EXAMPLE 5
[0081] A sample of unfiltered commercial soy biodiesel having 117
ppm steryl glycosides and filtered commercial soy biodiesel (having
68 ppm steryl glycosides) produced at the same facility were
subjected to the Filter Blocking Test. The unfiltered and the
filtered soybean biodiesel failed the FBT test by exceeding 105 kPa
pressure after 20 ml, to yield FBT values of 15.03. The filtered
soy biodiesel (1000 g) was passed through a bed of 5 grams of
diatomaceous earth at room temperature to yield a treated biodiesel
having a steryl glycoside content of 20 ppm which passed the FBT
test with an FBT value of 1.01.
EXAMPLE 6
[0082] The commercial unfiltered soy biodiesel from Example 5 (1000
g) was filtered through a 5 gram bed of diatomaceous earth (DE) at
room temperature and at 60.degree. C. using the procedure of
Example 4. The biodiesel filtered through the diatomaceous earth at
room temperature had an FBT value of 1.01 and contained 34 ppm
steryl glycosides. The biodiesel filtered through diatomaceous
earth at 60.degree. C. had an FBT value of 1.20 and contained 39
ppm steryl glycosides.
EXAMPLE 7
[0083] Diatomaceous earth was tested as a "body feed" for treating
biodiesel. Commercial soy biodiesel (555 g) was treated by
slurrying the soy biodiesel with 5 g DE (Altofina Clarcel DIT/2R SA
25K, AltoFina, King of Prussia, Pa.), stirring the slurry for 10
minutes at 500 rpm, and filtering the slurry through a 0.95 cm deep
bed of DE on a 4 cm diameter Schleicher & Schuell "White Ribbon
Filter" filter paper (Grade 598/2: 4-12 micron retention, ashless
standard filter paper for medium fine precipitates (class 2b
according to DIN 53 135, from VWR/Sargent Welch Scientific Co.,
Buffalo Grove, Ill.). The filtration was carried out at room
temperature and the filtrate was cooled to 1.degree. C. After
cooling, the filtrate was analyzed to measure the FBT and contents
of glycerol esters in the untreated and treated biodiesels. The
results are shown in Table 6. TABLE-US-00006 TABLE 6 Monoacyl-
Diacyl- Triacyl- Temperature FBT glycerols glycerols glycerols
Untreated 15.03 0.639% 0.159% 0.0174% RT (.about.25.degree. C.)
1.03 0.624% 0.160% 0.0169% 1.degree. C. 1.03 0.616% 0.158%
0.0171%
[0084] Although the content of glycerol esters was virtually
unchanged by the filtration treatment at both temperatures, the FBT
values were greatly affected. The unfiltered biodiesel failed the
FBT test after only 20 ml had passed through the FBT filter, but
the treated biodiesel showed excellent FBT values, showing that
improvement of FBT by filtering through DE under these conditions
was not dependent on removal of the glycerol esters that can cause
filter blockage.
EXAMPLE 8
[0085] A purified steryl glycoside composition was prepared by
filtration through granulated sugar. After treating 1000 mL of soy
biodiesel with a bed of granular sugar (15 g, 1.2 cm deep) as
described in Example 4, the bed of granular sugar was washed with
hexane to remove the biodiesel from the bed of granular sugar. The
composition of soy biodiesel is given in Table 7. Warm wash water
was applied to the carbohydrate solid bed material (granular
sugar). The solid bed material that dissolved in the wash step left
behind a steryl glycoside composition comprising 92% steryl
glycoside.
[0086] The entire lot of treated biodiesel was refrigerated for 3
days at 2.2.degree. C. (36.degree. F.). A visible cloud formed. The
treated, refrigerated biodiesel was filtered through a second bed
of granular sugar (approximately 2 cm. in depth). The filter bed
was washed with cold (-6.degree. C.) hexane. Water was applied to
the second bed of granular sugar to dissolve the sugar, and
material remaining on the filter was recovered. This material was
washed with water and dried at 70.degree. C. The material partially
melted and formed a waxy solid when cooled. The waxy solid was
predominantly monoacylglycerols (>90%, Table 7) and contained
0.67% steryl glycosides. TABLE-US-00007 TABLE 7 Composition of
biodiesel and waxy solid. Commercial Waxy Sample Id biodiesel solid
Fatty acid methyl 97.89 4.81 esters Monoacylglycerols 0.74 94.01
Diacylglycerols 0.27 1.03 (DAG) Triacylglycerols <0.01 <0.01
(TAG) Free fatty acids 0.12 0.06 Free glycerol <0.01 0.10
[0087] The monoacylglycerol-rich waxy solid was enriched in
(greater than 92%) of saturated monoacylglycerols (Palmitic C16:0
and Stearic C18:0, Table 8).
EXAMPLE 9
[0088] TABLE-US-00008 TABLE 8 Fatty acid composition of waxy solid.
Commercial Sample biodiesel Waxy solid Palmitic C16:0 10.24 53.15
Stearic C18:0 4.40 32.73 Oleic C18:1n9 cis 21.87 2.05 Linoleic
C18:2n6 cis 50.48 3.31 Linolenic C18:3n3 cis 7.70 0.58 Total
Saturated FAs 15.81 92.59
[0089] Biodiesel containing 22 ppm steryl glycosides was obtained
by combining the biodiesel filtered through sodium chloride (22 ppm
steryl glycosides) obtained in Example 4 with the biodiesel
filtered through citric acid (22 ppm steryl glycosides) obtained in
Example 4. Purified steryl glycosides obtained using the treatment
of Example 8 were added at known levels (10, 30, and 50 ppm) to the
biodiesel to produce biodiesel of various steryl glycosides
contents, which were subjected to the Filter Blocking Tendency test
(Table 9). TABLE-US-00009 TABLE 9 FBT values of biodiesel with
added steryl glycosides. Steryl glycoside FBT content value 22 ppm
(control) 1.05 32 ppm 1.47 52 ppm 2.90 72 ppm 15.03
[0090] All of the biodiesel samples containing additional steryl
glycosides failed the FBT (FBT values greater than 1.414).
EXAMPLE 10
[0091] Soy biodiesel (400 g) having an FBT value of 15.03 was
blended with 12 grams of deoiled soy lecithin and subjected to a
degumming procedure. The mixture was heated and mixed vigorously to
disperse the lecithin in the biodiesel. Deionized water (12 grams)
was added to the mixture and the mixture was agitated gently for
about 20 minutes. The mixture was subjected to centrifugation,
cooled to 40.degree. F. and held at that temperature for 16 hours.
The mixture was allowed to warm to room temperature and subjected
to the filter blocking tendency test. The FBT value of biodiesel
treated in this manner was 1.02 (passed). The heavy phase is
expected to be enriched in steryl glycosides.
EXAMPLE 11
[0092] Commercial unfiltered biodiesel (1000 g, labeled "Feed BD")
at room temperature (i.e., .about.72.degree. F.) was divided into
two lots, and each lot was passed through a separate bed of
diatomaceous earth (DE) (5 g). The DE filter cake was labeled "DE
filter cake" and the biodiesel that had passed through the filter
was labeled "DE filtered BD". Each filter cake was washed with 200
ml room temperature hexane. One lot of filtrate (DE filtered BD)
was evaluated by the Filter Blocking Test and an FBT value of 1.01
was obtained. The other lot of filtrate (DE filtered BD) was cooled
for 72 hours in a cold bath at 37.degree. F. and divided into two
sublots of 250 g.
[0093] Each sublot of DE filtered BD was filtered through separate
beds of 15 g granular sugar and the filtrates were combined,
labeled "37.degree. F. DE filtered, cooled BD final" and analyzed.
The sugar filter beds were washed with 200 ml cold (-5.degree. C.)
hexane and the hexane wash filtrates were combined, evaporated to
remove hexane, labeled "37.degree. F. DE filtered, hexane
filtrate," and analyzed. The combined sugar filter beds (DE
filtered, hexane residue) were washed with 200 ml room temperature
water to remove sugar. The filter paper from the sugar beds was
dried at room temperature and the solid residue on the filter paper
was labeled "37.degree. F. twice filtered solid bed" and analyzed.
The results of the analysis are shown in Table 11. TABLE-US-00010
TABLE 11 37.degree. F. 37.degree. F. 37.degree. F. DE DE twice DE
DE filtered, filtered, filtered Feed filter filtered cooled BD
hexane solid BD cake BD final filtrate bed MAG 0.71 0.72 0.72 0.72
0.71 95.24 (%) DAG 0.15 0.2 0.2 0.18 0.15 0.02 (%) TAG 0.12 0.0 0.0
0.0 0.02 0 (%) SG 65 36 33 34 32 654 (ppm) FBT 15.03 --* 1.01 1.01
--* --* *not measurable
[0094] When biodiesel having a MAG content of 0.71% was filtered
through DE, cooled and filtered through sugar, the biodiesel passed
easily and quickly through the bed of sugar, and the content of
monoacylglycerol (MAG) was virtually unchanged. The small amount of
"37.degree. F. twice filtered solid bed" (0.2907 g) obtained by
treating biodiesel with DE at room temperature, cooling the
biodiesel, filtering through sugar, washing the sugar filter bed
(filter cake) with cold hexane, and washing the sugar filter bed
with room temperature water was almost exclusively
monoacylglycerols (greater than 95%) and was enriched in steryl
glycosides (SG, 654 ppm).
EXAMPLE 12
[0095] Commercial unfiltered biodiesel used in Example 11 (500 g,
labeled "Feed BD") was cooled for 72 hours in a cold bath at
37.degree. F. and divided into two sublots of 250 g. Each sublot
was filtered through separate beds of 15 g granular sugar and the
filtrates were combined, labeled "Filtered BD final," and analyzed.
The sugar filter beds were washed with 200 ml cold (-5.degree. C.)
hexane and the washed filter beds were combined, labeled "All
cooled hexane residue," and analyzed. The sugar filter bed was
washed with 200 ml room temperature water. The filter paper was
dried at room temperature and the solid residue on the filter was
labeled "All cooled solid residue" and analyzed. The results of the
analysis are shown in Table 12. TABLE-US-00011 TABLE 12 All cooled
All Feed Filtered hexane cooled solid BD BD final residue residue
MAG (%) 0.71 0.65 0.78 63.97 DAG (%) 0.15 0.2 0.15 0.13 TAG (%)
0.12 0.03 0.01 0.08 SG (ppm) 65 27 27 155699 FBT 15.03 --* 1.01 --*
*not measurable on this material
[0096] The flow of cooled biodiesel through sugar beds was not
rapid as it was in Example 11. This filter treatment reduced the
content of MAG in biodiesel, the content of SG decreased from 65 to
27, and the resulting biodiesel had excellent properties in the
Filter Blocking Test.
EXAMPLE 13
[0097] Commercial soy methyl esters containing 56 ppm steryl
glycoside failed the filter blocking test (FBT) with a filter
plugging tendency value of 30.0. Two solvents were tested as
co-solvents for the methyl esters; dimethyl acetamide (DMA, boiling
point 164.degree. C.) and methyl-s-pyrrolidinone (methyl
pyrrolidone, boiling point 202.degree. C.). Solvents (33 ml, 10 v/v
%) were mixed with 297 ml commercial soy methyl esters and stirred
with a magnetic stirrer overnight at room temperature, and filter
plugging tendencies were measured by FBT. The filter plugging
tendencies were improved as shown in table 13. In another test, the
methyl esters/solvents mixtures were stirred with a magnetic
stirrer for 6 days at room temperature, then FBT were measured. The
FBT passed the test (Table 13). TABLE-US-00012 TABLE 13 FBT of
biodiesel with added solvents Filter plugging Overnight 6 day
tendency .fwdarw. treatment treatment With 10% DMA 1.44 (fail) 1.06
(pass) With 10% pyrrolidone 1.80 (fail) 1.05 (pass)
EXAMPLE 14
[0098] Semisolid material (final filter cake) retained in a
production scale sock filter in a final polishing filtration step
of biodiesel manufacture (30 g) was mixed with 1000 ml diethyl
ether on a magnetic stirrer for 10 min. After mixing, the mixture
was centrifuged at 3000 rpm for 30 sec, and the solvent phase was
decanted. Hexane (1000 ml) was mixed with the pellet for 30
minutes, and the mixture was centrifuged and decanted the same way
for a total of three hexane washes. The pellet was recovered and
filtered through #1 filter paper to provide a residue cake. The
residue cake was oven-dried at 70.degree. C. overnight. About 3.4 g
of material was recovered and analyzed. The material was steryl
glycoside of 99.8% purity.
EXAMPLE 15
[0099] Steryl glycosides were measured in biodiesel made from
once-refined (OR) soybean oil (ADM, Decatur, Ill.) and refined,
bleached (RB) soybean oil (ADM Quincy IL). OR Soybean oil contained
189 ppm steryl glycosides, and RB soy contained 224 ppm steryl
glycosides. Samples of each oil were subjected to biodiesel
synthesis. About 500 ml oil was taken up in a round bottom flask
and heated to 90.degree. C. under house vacuum for 15 minutes to
remove traces of water. Dried oil (436 grams) was mixed with
anhydrous methanol (90.0 g) to provide a molar ratio of
triacylglycerols/methanol of 1/6 in a one-liter Erlenmeyer flask. A
magnetic stir bar was placed in the flask and stirring was started.
To the oil/methanol mixture was added 30% sodium methoxide catalyst
solution (7.6 ml; 0.5 wt % sodium methoxide based on oil weight).
This mixture was refluxed for 30 minutes, when the vessel was
removed from heat and cooled under reflux until boiling ceased. The
reaction mixture was transferred to a one-liter separatory funnel
and held for 10 minutes to separate. A phase separation took place,
and the lower phase (glycerol phase) was drained from the
separatory funnel. The reaction mixture (biodiesel) was transferred
to a one-liter round bottom flask and washed by mixing with 44 ml
warm (.about.70.degree. C.) water with agitation. After ten
minutes, the bottom phase was removed with a pipette and the wash
procedure was repeated twice for a total of three washes. The
washed biodiesel was transferred to a separatory funnel, remaining
visible wash water was removed, and the biodiesel was dried by
heating to 90.degree. C. under house vacuum and holding for 20
minutes. The wash waters were combined and concentrated by
evaporation on a rotary evaporator. After biodiesel synthesis,
steryl glycosides were concentrated in the wash water (Table
14).
[0100] Steryl glycoside content (ppm) in biodiesel process streams
made from once-refined (OR) and refined, bleached (RB) soybean oil.
ND=not detected. TABLE-US-00013 TABLE 14 Steryl glycoside content
(ppm) in biodiesel process streams made from once-refined (OR) and
refined, bleached (RB) soybean oil. SG in SG in biodiesel from OR
biodiesel from RB oil (ppm) oil (ppm) Feed oil 189 224
Transesterification reaction 78 64 mixture Glycerol phase ND ND
Ester phase after water 59 ND wash Wash water concentrate 1054 2294
ND = not detected ND: Not detected
EXAMPLE 16
[0101] Commercial soy biodiesel (B100, comprising 100% soy
biodiesel) containing 58 ppm steryl glycosides was mixed with
petroleum diesel fuel obtained from a local filling station to
obtain blends (Table 15) which were subjected to the Filter
Blocking Test. The petroleum diesel fuel had a cloud point of
-19.6.degree. C., which is in the range of Number 2 diesel fuel.
B100 and B10 failed the filter blocking test, but blends
incorporating 2% and 5% biodiesel in conventional diesel (B2 and
B5, respectively) passed the filter blocking test (Table 15).
TABLE-US-00014 TABLE 15 Blends of commercial biodiesel and
conventional petroleum diesel fuel. Biodiesel FBT content (%)
Designation value Pass/fail 2% B2 1.01 Pass 5% B5 1.07 Pass 10% B10
1.74 Fail 100% B100 Fail
[0102] Commercial soy biodiesel (B100, comprising 100% soy
biodiesel) containing 58 ppm steryl glycosides was subjected to
filtration through diatomaceous earth substantially as described in
Example 5 to produce a B100 with reduced content of steryl
glycosides (37 ppm). The B100 with a reduced content of steryl
glycosides and blends with petroleum diesel (B10 and B20) passed
the filter blocking test (Table 16). TABLE-US-00015 TABLE 16 Blends
of filtered commercial biodiesel and conventional petroleum diesel
fuel. Biodiesel FBT content (%) Designation value Pass/fail 10% B10
1.01 Pass 20% B20 1.03 Pass 100% B100 1.01 Pass
EXAMPLE 17
[0103] Commercial soy biodiesel having a steryl glycoside content
of 69 ppm failed when subjected to the filter blocking test. The
effects of incubation of biodiesel at certain temperatures before
and after filtration through diatomaceous earth on steryl glycoside
content and FBT tendency were tested. A sample of biodiesel (1
liter) was held overnight at 70.degree. C., and incubated in a
water bath at a first temperature of 70.degree. F. (Table 17A),
50.degree. F. (Table 17B), or 40.degree. F. (Table 17C) for a first
incubation time. The incubated biodiesel (500 ml) was filtered
through a 5 gram precoat of diatomaceous earth, incubated at a
second temperature for a second period as indicated in Table 17A,
17B, and 17C, and subjected to the filter blocking test, and the
content of SG was determined. TABLE-US-00016 TABLE 17A First
incubation at room temperature (70.degree. F.). Pressure, First
Second Second Filter Steryl Incubation Incubation Incubation
Blocking Glycosides Test Time Temperature Time Test (kPa) (ppm)
Control 16 hours none None 6.08 ND* 17-1 6 hours 40.degree. F. 16
hours 1.01 38 17-2 6 hours RT 3 days 1.01 32 17-3 1 day RT 3 days
1.01 19 17-4 2 days RT 3 days 1.02 16 17-5 3 days RT 3 days 1.01 17
*nd, not determined due to failure on FBT test
[0104] TABLE-US-00017 TABLE 17B First incubation at 50.degree. F.
Pressure, First Second Second Filter Steryl Incubation Incubation
Incubation Blocking Glycosides Test Time Temperature Time Test
(kPa) (ppm) Control 16 hours none none 3.16 ND* 17-10 6 hours
40.degree. F. 16 hours 1.01 38 17-11 6 hours RT 3 days 1.01 27
17-12 12 hours RT 3 days 1.01 21 17-13 1 day RT 3 days 1.01 21 *nd,
not determined due to failure on FBT test
[0105] TABLE-US-00018 TABLE 17C First incubation at 40.degree. F.
Pressure, First Second Second Filter Steryl Incubation Incubation
Incubation Blocking Glycosides Test Time Temperature Time Test
(kPa) (ppm) Control 16 hours none None 15.03 ND* 17-6 6 hours
40.degree. F. 16 hours 1.01 33 17-7 6 hours RT 3 days 1.01 22 17-8
12 hours RT 3 days 1.01 25 17-9 1 day RT 3 days 1.02 60 *nd, not
determined due to failure on FBT test
[0106] Heating biodiesel to 70.degree. C. overnight followed by
incubating biodiesel at room temperature, or cooling biodiesel to
40.degree. F., or 50.degree. F. for as little as six hours before
filtering through a filter aid, proved to be an effective means of
reducing steryl glycosides and improving filter blocking test
results after a second incubation at 40.degree. F. or room
temperature (Tables 17A, 17B and 17C).
EXAMPLE 18
[0107] Commercial soy biodiesel having a steryl glycoside content
of 69 ppm failed when subjected to the filter blocking test. The
effects of treatment of biodiesel with activated carbon were tested
by stirring the carbon with soy biodiesel. A sample of biodiesel (1
liter) was heated overnight at 70.degree. C. This heated biodiesel
(500 ml) was stirred with carbon (SA4 carbon, Norit Americas, Inc.
Marshall, Tex.) in a water bath at a first temperature of
70.degree. C. for one hour. The incubated biodiesel (500 ml) was
filtered at 70.degree. C. through filter paper to remove the
carbon, incubated at a second temperature (RT) for a second period
(three days), and tested to determine the filter blocking tendency
and the content of SG. TABLE-US-00019 TABLE 18A Effect of carbon
treatment with two incubation periods on FBT and steryl glycoside
content. Carbon Second Second Pressure, Steryl Added Incubation
Incubation Filter Blocking Glycosides Test (%) Temperature Time
Test (kPa) (ppm) 18-1 0.25 RT 3 days 1.02 37 18-2 0.5 RT 3 days
1.02 35 18-3 1.0 RT 3 days 1.02 28
[0108] Carbon treatment was effective in reducing the FBT and
steryl glycoside content of biodiesel (Table 18A).
[0109] Commercial soy biodiesel having a steryl glycoside content
of 69 ppm failed when subjected to the filter blocking test. The
effects of treatment of biodiesel with SA4 carbon or PWA carbon
(Calgon Carbon Corp, Pittsburg, Pa.) were tested by stirring with
soy biodiesel. A sample of biodiesel (1 liter) was heated overnight
at 70.degree. C. This heated biodiesel (500 ml) was stirred with
carbon in a water bath at a first temperature of 70.degree. C. for
one hour. The incubated biodiesel (500 ml) was filtered at
70.degree. C. through a precoat of diatomaceous earth, incubated at
a second temperature for a second period, and tested to determine
the filter blocking tendency and the content of SG. TABLE-US-00020
TABLE 18B Carbon treatment and DE filtration. Filter Second Second
Pressure, Steryl Carbon DE Incubation Incu- Filter Glyco- Added,
amount Tempera- bation Blocking sides Test (%) (g) ture Time Test
(kPa) (ppm) 18-4 SA4, 1 g DE 40.degree. F. 20 hours 1.16 39 0.5%
18-5 SA4, 1 g DE RT 7 days 1.39 39 0.5% 18-6 PWA, 5 g DE RT 3 days
1.01 26 1.2%
[0110] Carbon treatment and incubation was effective in reducing
the FBT and steryl glycoside content of biodiesel (Table 18B).
[0111] Commercial soy biodiesel having a steryl glycoside content
of 69 ppm failed when subjected to the filter blocking test. A
sample of biodiesel (1 liter) was heated overnight at 70.degree. C.
The effects of treatment of biodiesel with CPG LF granular
activated carbon (Calgon Carbon Corp. Pittsburg, Pa.) were tested
by passing this heated soy biodiesel (500 ml) at 0.72 grams/minute
through a bed of CPG LF granular activated carbon (11.5 grams) in a
jacketed column (12 mm.times.40 mm) held at 70.degree. C. The
carbon-treated biodiesel was filtered at 70.degree. C. through
filter paper, incubated at a second temperature (room temperature)
for three days, and tested to determine the filter blocking
tendency and the content of SG. The FBT value was 1.02 and the
content of steryl glycosides was 31 ppm.
EXAMPLE 19
[0112] Commercial soy biodiesel having a steryl glycoside content
of 65 ppm and monoacylglycerol content of 0.71% which failed the
FBT test was filtered through DE at room temperature to obtain
filtered soy biodiesel having a steryl glycoside content of 33 ppm,
a monoacylglycerol content of 0.72%, and an FBT value of 1.01. The
filtered soy biodiesel and an unfiltered control of commercial soy
biodiesel were cooled to 33.degree. F. and stored at 33.degree. F.
The filtered soy biodiesel remained clear for several days of
incubation at 33.degree. F. The unfiltered control biodiesel became
visibly hazy after 1 day of incubation at 33.degree. F. and this
control was filtered through filter paper. The monoacylglycerol
content of the filtered control biodiesel thus obtained was reduced
to 0.65% and the steryl glycoside content was reduced to 27 ppm;
the solid residue (filter cake) obtained contained 63.97%
monoacylglycerols. Thus, the steryl glycosides enabled removal of
monoacylglycerols from the soy biodiesel by filtration, possibly by
providing nucleation sites for development of haze or crystals
enriched in monoacylglycerols.
EXAMPLE 20
[0113] Soy methyl esters containing 142 ppm steryl glycosides were
washed at 150.degree. F. by mixing with 10% of a solution
containing 2% boric acid for 15 minutes. The mixture was
centrifuged and the methyl ester phase dried. The resulting methyl
esters contained 41 ppm steryl glycosides and passed the filter
blocking test (FBT=1.04).
EXAMPLE 21
[0114] Soy methyl esters containing 69 ppm steryl glycosides and
FBT=15.03 were treated by adding 1.2% powdered carbon (Calgon PWA)
at 15.degree. F. and stirring for 1 hour. The treated methyl esters
plus carbon were filtered at 158.degree. F. with 47 mm diameter #1
filter paper and 5 g of diatomaceous earth. The treated and
filtered soy methyl esters contained 26 ppm steryl glycosides and
passed the filter blocking test (FBT=1.01).
EXAMPLE 22
[0115] Soy methyl esters containing 69 ppm steryl glycosides and
FBT=15.03 were treated by passing through a packed bed of granular
carbon (11.5 g Calgon CPG LF 12.times.40 in a 13.5 cm
high.times.1.5 cm diameter column) at 158.degree. F. and a flow
rate of 2 BV/hour. The FBT of the effluent methyl esters was tested
(Table 19). TABLE-US-00021 TABLE 19 FBT values of biodiesel passed
through a bed of carbon. FBT Untreated methyl esters 15.03 Methyl
esters collected 0-18 hours 1.02 Methyl esters collected 18-24
hours 1.02
EXAMPLE 23
[0116] Soy methyl esters containing 69 ppm steryl glycosides and
FBT=15.03 were treated as described in Example 22 except that the
flow rate was 4 BV/hour. The effluent methyl esters collected for
24 hours failed the filter blocking test (FBT=2.36).
EXAMPLE 24
[0117] Soy methyl esters containing 69 ppm steryl glycosides and
FBT=15.03 were treated by mixing with Norit SA4-PAH-HF carbon for 1
hour at 158.degree. F. as a "body feed" and then filtered at
158.degree. F. through 47 mm diameter #1 filter paper without
additional filter aid precoat. The filtered methyl esters were
allowed to incubate for 3 days at room temperature prior to testing
for filter blocking tendency (Table 20). TABLE-US-00022 TABLE 20
FBT values of biodiesel mixed with carbon body feed and filtered.
Carbon added (%) FBT 0.25 1.02 0.50 1.02 1.00 1.02
EXAMPLE 25
[0118] Soy methyl esters containing 54 ppm steryl glycosides and
FBT=15.03 were incubated for 6 or 12 hours at 40.degree. F. or
50.degree. F. prior to filtering with 5 g diatomaceous earth and
the filtered soy methyl esters were tested for filter blocking
tendency (Table 21). All 4 samples passed the filter blocking test
(FBT=1.01-1.02). For comparison, fresh soy methyl esters containing
69 ppm steryl glycosides and FBT=15.03 were incubated for 1, 2, and
3 days at room temperature prior to filtering with 5 g diatomaceous
earth (Table 21). All 3 of these samples also passed the filter
blocking test (FBT=1.01-1.02) after storage. TABLE-US-00023 TABLE
21 Steryl glycoside content of biodiesel after incubation and
filtering through diatomaceous earth. Incubation Incubation/storage
Steryl glycoside temperature (.degree. F.) time content (ppm) 40 6
hours 22 40 12 hours 25 50 6 hours 27 50 12 hours 21 70 (Room 1 day
19 temperature) 70 (Room 2 days 16, 29 (two tests) temperature) 70
(Room 3 days 17, 29 (two tests) temperature)
EXAMPLE 26
[0119] Soy methyl esters containing 69 ppm steryl glycosides and
FBT=15.03 were treated with 0.5% carbon (Norit SA4-PAH-HF) as a
body feed by mixing for 1 hour at 158.degree. F. and then filtered
at 158.degree. F. with 47 mm diameter #1 paper and 1 g diatomaceous
earth bed. The treated and filtered methyl esters were chilled for
20 hours at 40.degree. F. prior to testing for filter blocking
tendency; the FBT of the carbon-treated, filtered, biodiesel after
incubation at 40.degree. F. was 1.16.
EXAMPLE 27
[0120] Cellulose (EFC 450 from J. Rettenmaier, Rosenberg, Germany)
was added to unfiltered soy methyl esters (having an FBT value of
15.03, fail) at 25 kg cellulose to 12 metric tons methyl esters and
stirred for 1 hour. This mixture was used to precoat an industrial
dewaxing filter to a depth of 3 mm. Soy methyl esters (180 metric
tons) were chilled and incubated (stored) for one week at 52
-70.degree. F., and filtered at a rate of 20 metric tons/hr through
the cellulose precoat. The total back-pressure remained stable at
7.25 psig during the entire filtration process. Three samples of
biodiesel filtered through cellulose taken at different times
during the filter process all passed the filter blocking test
(FBT=1.02 to 1.04).
EXAMPLE 28
[0121] Three different batches of fresh commercial soy methyl
esters (one each from Mainz, Leer, or Hamburg, all of Germany) were
filtered as described in Example 27. Samples of the treated methyl
esters were incubated in a water bath at 40.degree. F. for 16 hours
prior to running the filter blocking test. All three samples passed
the Filter Blocking Test (FBT=1.01-1.03).
EXAMPLE 29
[0122] Distilled soy methyl esters were spiked with a steryl
glycoside solution in pyridine such that the steryl glycoside
concentration in the distilled soy methyl esters would be 25 ppm
after the pyridine was removed. The mixture was treated with heat
and vacuum to remove the pyridine and the methyl esters containing
25 ppm steryl glycosides were then chilled for 2, 4, and 6 hours at
40.degree. F. prior to filtering at 40.degree. F. with through a
precoat of 5 g diatomaceous earth on 47 mm diameter #1 paper. The
filtered samples were stored for 16 hours at 40.degree. F. Samples
were allowed to warm to room temperature without external heat
source and then tested by the filter blocking tendency test.
TABLE-US-00024 TABLE 22 FBT values for distilled methyl esters
containing 25 ppm added steryl glycosides. Incubation time at
40.degree. F. Incubation before filtration Filter time at
40.degree. F. after No. (hours) medium filtration (hours) FBT 1 0
None 0 15.03 2 2 DE* 2 5.10 3 4 DE 4 2.90 4 6 DE 6 1.20 *DE:
Diatomaceous Earth
EXAMPLE 30
[0123] Samples were prepared as described in Example 29 except that
steryl glycoside concentration was 100 ppm. Samples were incubated
and filtered as shown below. Samples were filtered at the
incubation temperature, the filter used was 47 mm diameter #1, and
5 g of diatomaceous earth was used when applicable. All filtered
samples were then incubated for 16 hours at 40.degree. F. The
samples were allowed to warm to room temperature without external
heat source and then tested for filter blocking tendency.
TABLE-US-00025 TABLE 23 FBT values for distilled methyl esters
containing 100 ppm added steryl glycosides. Incubation Incubation
time before filtration temperature before Filter No. (hours)
filtration (.degree. F.) medium FBT 1 6 40 None 15.03 2 2 40 DE* 3
4 40 DE 4 6 40 DE 1.01 5 6 75 DE *DE: Diatomaceous Earth
EXAMPLE 31
[0124] Fresh soy methyl esters containing 55 ppm steryl glycosides
were incubated for 6 hours at 40.degree. F. immediately after
synthesis substantially as described in Example 15 and divided into
four lots. Each lot was filtered at 40.degree. F. through 5 gram
precoats of one of the following filter aids on using 47 mm
diameter #1 filter paper: diatomaceous earth, Filtracel 250C
cellulose, J. Rettenmaier Filtracel 250C+ cellulose, and Filtracel
450 cellulose. All filtered samples were then stored at 40.degree.
F. for 16 hours, allowed to warm to room temperature, and tested
for filter blocking tendency. TABLE-US-00026 TABLE 24 Filter
blocking tendency of treated fresh soy methyl esters. Filter aid
FBT Diatomaceous 1.02 earth Filtracel 250C 1.03 Fitracel 250C+ 1.07
Filtracel 450 1.02
EXAMPLE 32
[0125] Soy methyl esters, FBT=15.03, were treated with
beta-glucosidase (Sigma). A solution of 0.2 g beta-glucosidase in
40 g water was added to 400 g soy methyl esters. The mixture was
heated to 104.degree. F. at ambient pressure and allowed to stir
for 24 hours. The mixture was transferred to a separatory funnel
and the water phase drained. The methyl ester phase was dried for
20 minutes at 194.degree. F. under vacuum. The dried methyl esters
were stored at 40.degree. F. for 16 hours prior to testing for
filter blocking tendency (FBT=3.88).
EXAMPLE 33
[0126] Soy methyl esters were synthesized by incubating soybean oil
with methanol and catalyst substantially as outlined in Example 15.
The FBT value of freshly synthesized soy methyl esters, after water
washing three times with 10 vol % water, was 10.05 (Table 23). In
some embodiments, the water washing step was eliminated and fresh
soy methyl esters were treated with silica hydrogel (PQ Corporation
29-4) before or after a drying step. When methyl esters were dried
as indicated in Table 23, where applicable, the reaction product
was dried by incubation for 20 minutes at 90.degree. C. under
vacuum 10 and allowed to cool to room temperature. Hydrogel
treatment was carried out on dried or undried methyl ester by
heating methyl esters to 65.degree. C., adding Silica Hydrogel 29-4
(PQ Corporation, Valley Forge, PA) as indicated in Table 23, and
stirring for 10 minutes at 65.degree. C. Vacuum was applied and the
methyl esters and hydrogel were heated to 90.degree. C. and held at
90.degree. C. for 20 minutes. The mixture 15 was cooled to
70.degree. C., the vacuum was released, and the mixture was
filtered through #50 (medium) filter paper in a Buchner funnel.
Immediately after filtering, all samples were placed in 40.degree.
F. bath for 16 hours. The samples were allowed to warm to room
temperature and tested for filter blocking tendency. TABLE-US-00027
TABLE 25 Filter Blocking Tendency of fresh soy methyl esters RBD
soy methyl Methyl esters esters treated FBT Water wash control
Undried 10.05 3.times. 10% (fail) Silica hydrogel 0.25% Dried 2.69
(fail) Silica hydrogel 0.5% Undried 6.08 (fail) Silica hydrogel
0.5% Dried 1.08 (pass) Silica hydrogel 1% Undried 1.14 (pass)
Silica hydrogel 1% Undried 1.60 (fail) Silica hydrogel 1.5% Undried
1.09 (pass) Silica hydrogel 2% Undried 1.22 (pass)
[0127] The silica hydrogel treatment produced methyl esters which
passed the filter blocking test while eliminating the water washing
step.
EXAMPLE 34
[0128] The filter blocking tendency test (FBT, ASTM D2068) was
compared to a modified ASTM D6217 test which may be used as a
biodiesel specification. The FBT test was carried out as described
above. The modified 6217 test was carried out as follows: biodiesel
(300 ml) was filtered through a 1.6 um GF/A filter having 47 mm
diameter under a 21-25 inch Hg vacuum. To pass the test, the entire
sample of 300 ml must pass through the filter in 6 minutes. In
every case, biodiesel that passed the FBT test also passed the
modified D6217 test. Table 26 reports the time required for 300 ml
to pass through the filter for passing samples, and the volume
passed through the filter in 6 minutes for failing samples.
TABLE-US-00028 TABLE 26 Comparison of ASTM D2068 and Modified ASTM
D6217 (mls = milliliters). ASTM D6217 ASTM D2068 Time Methyl (FBT)
(min) or ester (ME) FBT volume Canola 1.03 pass 0:30 pass Tallow
5.10 fail 1:30 pass Soy 2.36 fail 3:45 pass Soy 15.03 fail 130 fail
mls Soy 15.03 fail 180 fail mls Canola 4.4 fail 1:04 pass Canola
10.05 fail 200 fail mls Animal 10.05 fail 2:04 pass Poultry 15.03
fail 115 fail mls Tallow 3.88 fail 0:28 pass Soy 7.57 fail 0:55
pass Soy 15.03 fail 1:47 pass Soy 1.01 pass 0:25 pass Soy 6.08 fail
0:26 pass
[0129] The exemplary embodiments described herein are not intended
to limit the invention or the scope of the appended claims. Various
combinations and modifications of the embodiments described herein
may be made without departing from the scope of the present
disclosure and all modifications are meant to be included within
the scope of the present disclosure. For instance, the various
embodiments of the biodiesel treatments described herein may be
used in conjunction with other embodiments of the biodiesel
processing activities described herein. Further, the biodiesel
treatment activities described herein may be implemented by
modifying existing biodiesel processing systems and used in
conjunction with existing biodiesel processing equipment. Thus,
while certain exemplary embodiments and details have been described
for purposes of exemplifying the invention, it will be apparent to
those of ordinary skill in the art that various changes to the
invention described herein may be made in any combination without
departing from the scope of the present disclosure, which is
defined in the appended claims.
* * * * *
References