U.S. patent application number 14/834286 was filed with the patent office on 2016-03-03 for process for purifying oils and products produced from the purified oils.
The applicant listed for this patent is Eco-Collection Systems LLC. Invention is credited to Cameron C. Calhoun, Joseph M. Perez.
Application Number | 20160060565 14/834286 |
Document ID | / |
Family ID | 55401775 |
Filed Date | 2016-03-03 |
United States Patent
Application |
20160060565 |
Kind Code |
A1 |
Perez; Joseph M. ; et
al. |
March 3, 2016 |
PROCESS FOR PURIFYING OILS AND PRODUCTS PRODUCED FROM THE PURIFIED
OILS
Abstract
Processes for purifying used cooking oil, and for isolating
fractions from the used cooking oil that can be used in biodiesel
and lubricant compositions, are described. Winterization of used
cooking oil allows separation of particulate impurities, and the
resulting oil can be further winterized to allow the oil to
separate into fractions which include relatively higher and
relatively lower FFA concentrations than the starting oil.
Fractions can then be isolated, and those fractions with
sufficiently low FFA concentrations can be used in biodiesel
applications, and fractions with relatively higher FFA
concentrations can be used in certain lubricant formulations,
including chain saw lubricants and mould release oil
compositions.
Inventors: |
Perez; Joseph M.;
(University Park, PA) ; Calhoun; Cameron C.;
(Wilmington, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Eco-Collection Systems LLC |
Wilmington |
NC |
US |
|
|
Family ID: |
55401775 |
Appl. No.: |
14/834286 |
Filed: |
August 24, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62044036 |
Aug 29, 2014 |
|
|
|
Current U.S.
Class: |
508/111 |
Current CPC
Class: |
C10M 175/005 20130101;
C10N 2040/36 20130101; C10N 2040/38 20200501; C10N 2040/32
20130101 |
International
Class: |
C10M 175/00 20060101
C10M175/00 |
Claims
1. A method of processing used cooking oil to recover material
therefrom, wherein the used cooking oil has a first fatty acid
concentration, said method comprising: a) cooling the used cooking
oil to temperature between about -6.degree. C. and about 10.degree.
C., and maintaining it at such temperature for a period of time
between about 3 hours and about four weeks, b) warming the used
cooking oil to temperature between about 115.degree. C. and
140.degree. C., c) sedimenting solid impurities from the used
cooking oil, d) separating the oil from the sedimented solid
impurities, e) subjecting the separated oil to a winterization, and
f) isolating from the winterized oil a fraction with a second fatty
acid concentration, which is higher than the first fatty acid
concentration, and a fraction with a third fatty acid
concentration, which is lower than the first fatty acid
concentration.
2. The method of claim 1, wherein the separated oil is subjected to
more than one winterization.
3. The method of claim 1, wherein the solid impurities are used as
a diluent or a plasticizer for roofing tars or asphalts.
4. The method of claim 1, wherein the used cooking oil comprises
water, and the method further comprises removing water from the
used cooking oil prior to said cooling a).
5. The method of claim 4, wherein the water is removed using a
heating and settling process, comprising heating the oil to
temperature above 120.degree. C., and maintaining the oil at such
temperature for a period of time of 36 hours or longer.
6. The method of claim 1, wherein the winterization comprises
cooling the oil to temperature of about 10.degree. C., and
maintaining it at such temperature for a period of time between
about two and four weeks.
7. The method of claim 1, wherein one or more of the oil fractions
includes a higher free fatty acid concentration than a
predetermined amount for a given application, further comprising
removing fatty acids therefrom.
8. The method of claim 7, wherein the fatty acids are removed via
neutralization and extraction, or via filtration through clay.
9. A lube base stock prepared by the method of claim 1.
10. A chain saw lubricant comprising a lube base stock prepared by
the method of claim 1.
11. The chain saw lubricant of claim 10, further comprising one or
more additives selected from the group consisting of tackifiers,
pour point depressants, anti-wear additives, rust inhibitors, and
antioxidants.
12. The chain saw lubricant of claim 11, comprising a pour point
depressant at concentration of about 1.5% by weight, an anti-wear
additive at concentration of between 0.1 and 1% by weight, an
antiwear additive at a concentration of between 0.1 and 1% by
weight, a rust protector between 0.1 and 1% by weight, and an
antioxidant at concentration between 0.1 and 1% by weight, wherein
all weight percentages are based on total weight of the chain saw
lubricant.
13. A mould release fluid comprising a lube base oil prepared
according to the method of claim 1.
14. The mould release fluid of claim 13, wherein the mold release
fluid comprises a lube base oil, an organic solvent, a tackifier,
between 0.1 and 1% by weight of a rust inhibitor, between 0.1 and
1% by weight of an antioxidant, and optionally between 0.1 and 3%
by weight of a demulsifier and/or between 0.1 and 1% by weight of
an odorant, wherein all weight percentages are based on total
weight of the mold release fluid.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The benefit of priority under 35 USC .sctn.119 of U.S.
Provisional Patent Application No. 62/044,036 filed Aug. 29, 2014
in the names of Joseph M. Perez and Cameron C. Calhoun for "PROCESS
FOR PURIFYING OILS AND PRODUCTS PRODUCED FROM THE PURIFIED OILS" is
hereby claimed. The disclosure of such U.S. Provisional Patent
Application No. 62/044,036 is hereby incorporated herein by
reference, in its entirety, for all purposes.
FIELD
[0002] The present disclosure relates to process for separating
used cooking oil into different fractions, including a fraction
with a relatively lower free fatty acid concentration than the
starting oil, and a fraction with a relatively higher free fatty
acid concentration than the starting oil. The present disclosure
also relates to processes for producing biodiesel fuels from the
fraction with a relatively lower free fatty acid concentration than
the starting oil, and producing lubricants from the fraction with a
relatively higher free fatty acid concentration than the starting
oil.
BACKGROUND
[0003] Although fatty acids are typically present in low
concentrations in virgin cooking oils, as they are used, the
concentration of fatty acids increases, and once used cooking oils
reach certain high fatty acid concentrations, they are no longer
suitable for use in cooking applications.
[0004] There is a large market for used cooking oils in the
biodiesel fuel and lubricant fields, because they are available at
a much lower price than virgin cooking oils. However, there are
also impurities in used cooking oils that may make them difficult
to use as feedstocks to prepare biodiesel fuel or lubricants. These
impurities include fatty acids, solids, and, occasionally, waxes.
For some products, the presence of fatty acids and waxes may be
advantageous. However, for biodiesel production, the presence of
fatty acids is problematic, because biodiesel is produced via
transesterification, a base-catalyzed reaction. Fatty acids react
with the basic transesterification catalysts to form fatty acid
carboxylate salts. These salts function as emulsifiers, making it
difficult to separate the biodiesel from the crude glycerol
by-product that is produced.
[0005] Phase separation also constitutes a major problem with used
cooking oils when they are used in lubricant products. In most
lubricant applications, including hydraulic fluids, chainsaw
lubricants, mould release fluids and cutting oils, phase separation
is considered as a major issue. Typically, these products include
functional additives in addition to an oil base. If the functional
additives were to precipitate out of the oil, the remaining fluid
would not perform properly. However, with used cooking oils,
precipitates can form, and while these precipitates may not include
the functional additives, a customer might believe that such is the
case. Therefore, in order to effectively use re-processed waste oil
in lubricants, it would be desirable for manufacturing procedures
to minimize sediment formation.
[0006] It would therefore be advantageous to have an efficient
method to remove impurities from used cooking oil, and to recover
products which include the oil from which the impurities are
removed. The present disclosure provides such methods and
products.
SUMMARY
[0007] Processes for treating used cooking oil to remove various
impurities, and to provide various isolated fractions with
different impurity profiles, are disclosed. Processes for using
isolated fractions from the treated used cooking oil to produce
biodiesel fuel, and to produce lubricants, are also disclosed.
[0008] Used cooking oil includes a variety of impurities. These
predominantly include solids, including materials from the foods
cooked in the oils, and fatty acids. Depending on the source of the
oil, waxes can be present, though they may have already been
removed from the cooking oil before it was used, for example, in a
winterizing step. The processes described herein remove the solids,
and can provide fractions in which the fatty acid content is
relatively lower than in the starting material (used cooking oil),
and fractions in which the fatty acid content is relatively higher
than the starting material.
[0009] In one embodiment, the process starts in a restaurant, with
the oil being heated in a fryer to 300 to 400.degree. F. Typically,
the oil is collected, and water is removed through a heating and
settling process where the oil is heated to above 120.degree. C.,
and remains in the tank for 36 hours or longer. In another
embodiment, the process starts with used cooking oil that has
already been subjected to these steps, or which is not treated to
remove water.
[0010] The oil is then subjected to a chilling (i.e.,
winterization) process. When virgin oil is subjected to
winterizing, the majority of fats/waxes that are present tend to
crystallize out, and a filtering step removes the crystallized
fats/waxes. Accordingly, if the cooking oil that is recovered had
previously been winterized, the winterizing that occurs in this
step will not remove fats/waxes, as such would already have been
removed before the oil was used for cooking. However, fats or waxes
can be present in the oil as a result of the food that was cooked
in the oil, and can be removed in this winterizing step.
[0011] The winterizing step involves refrigerating the recovered
cooking oil for a given period of time, then allowing it to warm to
a temperature above the freezing point of the oil, typically around
room temperature, then allowing the oil to separate into a series
of fractions. The fractions typically include an upper layer of
"sheen," a bulk liquid layer, a cloudy phase, a slurry phase, and a
bottom layer including pasty residues.
[0012] The pasty residues tend to have much higher water contents
than the other layers. While not wishing to be bound to a
particular theory, it is believed that water micelles occur in the
oil, especially when high free fatty acids are present. These
colloidal structures form and, being heavier than oil, settle to
the bottom. Along with crystal formation, this is an important
mechanism for the formation of oil precipitates.
[0013] In order to remove these molecules, the process initially
involves cooling or refrigerating the oil, forcing their
crystallization. Then, the cold oil is allowed to thaw, which leads
to migration of more fluid molecules to the top of the oil and
sedimentation of solid molecules on the bottom. The solid molecules
can then be removed, for example, by filtering them out of the oil,
or by decanting the oil from the solid bottom fraction.
[0014] While not wishing to be bound to a particular theory, it is
believed that it is better to filter the oil only after it has been
cooled, because if it is filtered before it is cooled, crystal
seeds can be removed, which can lengthen the time for filtered
samples to form precipitates.
[0015] Once the pasty residues have been collected, they can be
used, for example, as a diluent (or a plasticizer) for roofing tars
and asphalts.
[0016] The remaining oil can be sent to a winterization tank or a
processing tank, where it is allowed to separate on cooling into
(at least) two fractions. Generally, one of the fractions includes
a relatively higher fatty acid content than another of the
fractions. The relatively high fatty acid content fraction(s) can
be used, for example, to produce lubricant formulations. When used
for at least certain lubricant formulations, the presence of fatty
acids is not detrimental.
[0017] The fraction(s) with relatively low fatty acid content can,
ideally, be used for biodiesel production. However, where the fatty
acid content is over 3 percent by weight, the fatty acid content is
still too high for use in conventional biodiesel production. The
fraction(s) can be subjected to another winterization step, which
re-fractionates the oil and provides a further fraction with lower
fatty acid content, or the fatty acid concentration can be reduced
in one or more fractions, for example, by extracting the
fraction(s) with a basic solution to lower the fatty acid
concentration, or by filtration through a clay, where the clay
intercalates fatty acid salts.
[0018] The apparatus used to process the used cooking oil may in
various embodiments include a processing tank, a holding tank, and
one or more winterization tanks. The oil is stored at a temperature
between about 115.degree. C. and 140.degree. C. for a period of
time between 48 and 72 hours in a processing tank. The processing
tank can include a drain at the bottom, enabling the pasty residues
to drain out once the residues separate from the remainder of the
oil. Further winterization steps can be performed in one, two, or
more winterization tanks. The tanks are ideally set up away from
heat sources or sunlight. In one embodiment, at least one of the
tanks includes a cold water jacket. In one embodiment, intake
piping is used to pump the oil from the top reservoir levels, and
in this embodiment, at least the winterization tanks are equipped
with such an intake system, although its installation in other
tanks can benefit the product quality as well.
[0019] It can be beneficial to equip tanks that include such intake
systems with a means for skimming the oil surface. Those of skill
in the art can readily ascertain how frequently the surface should
be skimmed.
[0020] In practice, a water cooling jacket is typically capable of
reducing the oil temperature to 10.degree. C. Oil cooled to this
temperature can be winterized in between about 2 and 4 weeks,
depending on the ambient temperatures. However, considerable
amounts (.about.20% by volume of the starting oil) of clear oil can
typically be sampled from the top of the winterization tanks as
early as in a week after winterization has been initiated.
[0021] Without any cooling, the winterization can take anywhere
from one month to several (e.g., 3-5) months, particularly if the
winterization occurs during the summer, though it occurs faster
during the winter. The cooling cycle in the beginning, followed by
the gradual thawing (warming up) and sedimentation, appears to be
much more effective in winterizing the oil than merely holding it
at ambient temperature.
[0022] In one embodiment, the heavy residue from the re-processed
oil is used as a diluent (or a plasticizer) for roofing tars and
asphalts. This embodiment provides a use for this product fraction,
rather than merely sending it off for disposal.
[0023] Using the winterization process described herein, one can
provide re-processed oils with a relatively higher quality than the
starting oils, and also provide for the use of such oils, or
fractions thereof, to produce "value added" products such as
biodiesel, lubricants, and hydraulic fluids.
[0024] In one aspect, the disclosure relates to a method of
processing used cooking oil to recover material therefrom, wherein
the used cooking oil has a first fatty acid concentration, said
method comprising:
[0025] a) cooling the used cooking oil to temperature between about
-6.degree. C. and about 10.degree. C., and maintaining it at such
temperature for a period of time between about 3 hours and about
four weeks, [0026] b) warming the used cooking oil to temperature
between about 115.degree. C. and 140.degree. C., [0027] c)
sedimenting solid impurities from the used cooking oil, [0028] d)
separating the oil from the sedimented solid impurities, [0029] e)
subjecting the separated oil to a winterization, and [0030] f)
isolating from the winterized oil a fraction with a second fatty
acid concentration, which is higher than the first fatty acid
concentration, and a fraction with a third fatty acid
concentration, which is lower than the first fatty acid
concentration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a drawing depicting the fractions present in a
winterized sample of used cooking oil.
[0032] FIG. 2 is a graphic illustration of a chemical plant that
receives a waste oil supply, and passes it through a processing
tank, a holding tank, and a winterization tank, to produce a
fraction including solid materials that can be used as a diluent
for roofing, an oil fraction that can be used as a feedstock for
biodiesel production, and an oil fraction that can be used as a
feedstock for lubricant production.
[0033] FIG. 3 is a graphic illustration of a chemical plant that
receives a waste oil supply, and passes it through a processing
tank, a holding tank, and two winterization tanks, to produce the
same fractions as shown in FIG. 2.
[0034] FIG. 4 is a chart showing the relative percentages (vol. %
vs. days) by volume of a liquid phase and a paste phase for two
different oil samples stored under various storage conditions over
various periods of time. Diamonds represent cold storage of a
sample labeled 7EC. Squares represent room temperature storage of a
sample labeled 7EC. Triangles represent cold storage of a sample
labeled 8EC. Circular dots represent room temperature storage of a
sample labeled 8EC.
[0035] FIG. 5 shows a schematic illustration of a chemical plant
for converting the oil fraction including relatively high fatty
acid contents into a lubricant composition, by mixing in various
additives.
[0036] FIG. 6 is a chart showing the viscosity of a lubricant
formulation (cSt at 40.degree. C.) as a function of the weight
percent of a particular additive, V-570.
[0037] FIG. 7 is a chart showing how used cooking oil proceeds from
being winterized and separated into a base oil for lubricant
manufacture and an oil for biodiesel production, how the base oil
is combined with additives to produce a lubricant formulation, and
how that formulation can optionally be subjected to quality
assurance and possible re-working.
[0038] FIG. 8 is a chart showing the pour point (degrees C.) of
various formulations (10%, 15%, and 20% POL V570) including various
percentages of pour point depressant (PPD) 551.
DETAILED DESCRIPTION
[0039] The methods described herein can be used to isolate various
products, or feedstocks useful to produce various products, from
waste cooking oil (also referred to herein as "re-processed oil" or
"used cooking oil"). In one embodiment, the methods can be used
on-site where waste cooking oils are produced, to manufacture
value-added lubricant and other products.
[0040] The methods described herein involve sedimentation, one or
more winterization steps, and separation. These process steps are
discussed in more detail below.
[0041] As used herein, the term "relatively low free fatty acid
("FFA") content" refers to FFA content between 0.1 and 3% by
weight. The term "relatively high free fatty acid ("FFA") content"
refers to FFA content greater than about 3% by weight. However, the
term "relatively" is also used herein to relate the FFA content of
one or more fractions to the FFA content of the starting oil,
and/or to relate the FFA content of one or more fractions to each
other.
[0042] The methods described herein allow one to separate waste
cooking oil, which often has a relatively high initial FFA content,
into fractions that include relatively higher FFA content and
relatively lower FFA content than the initial oil.
[0043] In some embodiments, where a sample of waste cooking oil has
an FFA content greater than 3%, and is subjected to the methods
described herein, the sample is separated into different fractions,
some of which have a low enough FFA content (i.e., less than 3% by
weight, preferably less than about 1% by weight) to be used as a
feedstock to produce biodiesel fuel.
[0044] In some embodiments, where a sample of waste cooking oil has
an FFA content greater than 3%, and is subjected to the methods
described herein, the sample is separated into different fractions,
some of which have a relatively lower FFA content, and some of
which have a relatively higher FFA content. The specification for
free fatty acids in certain products is higher than in other
products, so by providing different fractions with different FFA
contents, waste cooking oil with an FFA content too high for use as
feedstock for certain products can be separated into different
fractions, one or more of which may have a low enough FFA content
for use in different applications than the starting waste cooking
oil.
[0045] Examples of products that tolerate relatively high FFA
contents include chainsaw lubricants and mold release oils.
Examples of products that may require relatively lower FFA contents
include cutting oils and hydraulic fluids. A fraction otherwise
suitable for biodiesel production can also be used to prepare
lubricants, particularly those which require relatively low FFA
content.
[0046] In some embodiments, it is desirable to further reduce the
concentration of free fatty acids (i.e., Total Acid Number) in
addition to what can be accomplished through winterization. This
can be accomplished, for example, by neutralization and extraction,
or by filtration through clay.
[0047] In one illustrative aspect, the disclosure relates to a
method of processing used cooking oil to recover material
therefrom, wherein the used cooking oil has a first fatty acid
concentration, said method comprising:
[0048] a) cooling the used cooking oil to temperature between about
-6.degree. C. and about 10.degree. C., and maintaining it at such
temperature for a period of time between about 3 hours and about
four weeks,
[0049] b) warming the used cooking oil to temperature between about
115.degree. C. and 140.degree. C.,
[0050] c) sedimenting solid impurities from the used cooking
oil,
[0051] d) separating the oil from the sedimented solid
impurities,
[0052] e) subjecting the separated oil to a winterization, and
[0053] f) isolating from the winterized oil a fraction with a
second fatty acid concentration, which is higher than the first
fatty acid concentration, and a fraction with a third fatty acid
concentration, which is lower than the first fatty acid
concentration.
[0054] In various embodiments of such method, the separated oil may
be subjected to more than one winterization.
[0055] In other embodiments, the solid impurities are used as a
diluent or a plasticizer for roofing tars or asphalts.
[0056] In still other embodiments, the used cooking oil comprises
water, and the method further comprises removing water from the
used cooking oil prior to the cooling a). For example, the water
may be removed using a heating and settling process, comprising
heating the oil to temperature above 120.degree. C., and
maintaining the oil at such temperature for a period of time of 36
hours or longer.
[0057] In various embodiments of the above-described method, the
winterization comprises cooling the oil to temperature of about
10.degree. C., and maintaining it at such temperature for a period
of time between about two and four weeks.
[0058] In other embodiments, one or more of the oil fractions may
include a higher free fatty acid concentration than a predetermined
amount for a given application, further comprising removing fatty
acids therefrom. The fatty acids may be removed in any suitable
manner, e.g., via neutralization and extraction, or via filtration
through clay.
[0059] The disclosure relates in another aspect to a lube base
stock prepared by the method broadly described above.
[0060] In a further aspect, the disclosure relates to a chain saw
lubricant comprising a lube base stock prepared by the method
broadly described above. Such chainsaw lubricant may further
comprise one or more additives selected from the group consisting
of tackifiers, pour point depressants, anti-wear additives, rust
inhibitors, and antioxidants. Such chainsaw lubricant may further
comprise a pour point depressant at concentration of about 1.5% by
weight, an anti-wear additive at concentration of between 0.1 and
1% by weight, an antiwear additive at a concentration of between
0.1 and 1% by weight, a rust protector between 0.1 and 1% by
weight, and an antioxidant at concentration between 0.1 and 1% by
weight, wherein all weight percentages are based on total weight of
the chain saw lubricant.
[0061] The disclosure relates in a further aspect to a mold release
fluid comprising a lube base oil prepared according to the method
broadly described hereinabove. In various embodiments, the mold
release fluid may comprise a lube base oil, an organic solvent, a
tackifier, between 0.1 and 1% by weight of a rust inhibitor,
between 0.1 and 1% by weight of an antioxidant, and optionally
between 0.1 and 3% by weight of a demulsifier and/or between 0.1
and 1% by weight of an odorant, wherein all weight percentages are
based on total weight of the mold release fluid.
[0062] The processes for treating used cooking oil to remove
various impurities, to provide various isolated fractions with
different impurity profiles, and to use these isolated fractions to
form downstream products, are disclosed in more detail below.
I. Sources of Vegetable Oil/Animal Fat
[0063] Many restaurants use one or more vegetable oils to fry
foods. These oils include palm oil, soybean oil, corn oil,
cottonseed oil, and canola oil. These oils are typically subjected
to winterizing steps, and, optionally deodorizing and other steps,
before being used to cook food. Accordingly, recovered cooking oils
may contain relatively low amounts of impurities, such as fats and
waxes, which are found in virgin oils of these types. Since chicken
is often cooked in the oil, chicken fat is frequently found in the
used cooking oil.
[0064] Particulates from pieces of food, including bone, breading,
and the like, are also found in used cooking oil. Filtration can
typically remove the bulk of the particles, but may not be
effective at removing all of the particles.
[0065] Water is also typically present in cooking oil, as a result
of cooking food that includes relatively high water content in the
oil. For example, potatoes and chicken both include large amounts
of water, and although much of this water leaves the oil in the
form of steam, residual amounts of water can remain. While most
biodiesel production processes can tolerate up to 1% water in the
feedstock, even this small quantity of water will increase soap
formation and measurably affect the transesterification
process.
[0066] This water can be largely removed by heating the oil, as
described herein. However, a certain amount of water can remain in
the form of micelles, which include water, fatty acids, and
vegetable oil.
[0067] The free fatty acid content of used cooking oil is typically
in the range of between about 5% and 30% by weight. The fatty acid
content of trap grease is typically in the range of between about
40% and 100% by weight, which is typically too high for it to be
subjected to the processes described herein. The preferred range of
fatty acid content for used cooking oils used in the processes
described herein is between 4 and 10% by weight.
II. Initial Winterization Step
[0068] After the oil has been obtained, and excess water has been
removed, the oil can be cooled and the solid impurities allowed to
crystallize. Then, the oil is allowed to warm, and the various
phases are separated. The phases include at least a paste residue
bottom layer and slurry phase, a cloudy layer, and a bulk oil
layer, as shown in FIG. 1.
[0069] In one embodiment, the initial winterization step is
conducted at a temperature of between about -6.degree. C. and about
12.degree. C., preferably between about 6.degree. C. and about
10.degree. C., for a period of time between 3 hours and 4 weeks. If
desired, the initial winterization step can be carried out for
longer periods of time, such as up to two months, up to a year, or
up to a year and a half.
III. Filtration Step and Commercial Uses for the Corresponding
Filtrate
[0070] After the used cooking oil has been subjected to a first
winterization step, the oil allowed to warm to at or near room
temperature. Impurities that have crystallized and formed a pasty
residue at the bottom of the sample can be collected, for example,
by filtration, centrifugation, or decanting the top layer of oil
from the pasty residue.
[0071] The filtrate (i.e., the pasty residue) can be used, for
example, as a diluent (or a plasticizer) for roofing tars and
asphalts.
IV. Further Winterization Step(s)
[0072] After the pasty residue has been removed, the resulting
intermediate oil can still include relatively high fatty acid
content. However, when subjected to additional winterization steps,
the oil can separate into fractions that include relatively higher
and relatively lower fatty acid content. When used as a feedstock
for certain lubricant formulations, the oil can include relatively
higher fatty acid contents than can be present in oil to be used as
a feedstock to produce biodiesel. Accordingly, once the fractions
are separated using one or more additional winterization steps,
they can be separately isolated, for example, by draining a bottom
phase, or by decantation or centrifugation.
V. Optional Neutralization of Free Fatty Acids
[0073] Depending on the initial fatty acid concentration in the
used cooking oil, even after the oil has been subjected to
winterization, and one or more fractions with relatively lower
fatty acid concentrations than the initial used cooking oil are
obtained, the concentration may be too high for use in
transesterification reactions. In such a case, it is desirable to
reduce the fatty acid concentration in such fractions. This can
frequently be accomplished using a neutralization step or an
esterification step.
[0074] Neutralization of fatty acids can be accomplished by washing
the oil fractions with a basic solution. However, doing so tends to
waste otherwise usable free fatty acids. For example, if the free
fatty acid content of the used cooking oil was 10% by weight (which
is within the range of concentrations that might be obtained), and
the concentration is reduced up to half using the winterization
step, the resulting 5% by weight concentration of the fraction
would not be suitable for biodiesel production, at least if the
biodiesel was produced using a transesterification process. If 5%
of the weight of the oil were removed, for example, by extraction
into a basic aqueous solution or by intercalation into clay, the
quantity of biodiesel that can be produced is reduced by that
amount.
[0075] Esterification, on the other hand, does not remove the fatty
acids. Rather, the fatty acids are reacted with methanol or
ethanol, in the presence of an acid catalyst rather than a basic
catalyst, to convert the fatty acids to biodiesel. A limitation of
this type of process is that it adds an extra step, and one must
first remove the acid catalyst before performing a basic
transesterification step.
[0076] The fatty acids in the oil fraction(s) can be neutralized by
treating the oil fraction(s) with a lye solution, such as potassium
or sodium hydroxide (NaOH). This tends to form soap. The soap can
be removed from the oil by washing several times with clean water.
This involves removing soapy water by draining it from the bottom
of the oil, which is time consuming because the mixture must be
allowed to settle before the water can be removed.
[0077] In one embodiment, a neutralization step involves chilling
the oil fraction(s) to less than about 15.degree. C., for example,
between about -1.degree. C. and 10.degree. C., and, more typically,
around 4.degree. C. The fraction(s) are held at the chilled
temperature for an hour or more. Then, an alkali solution is added,
typically in the range of from about 10 to about 30% by weight of
the total mixture of oil and alkali solution.
[0078] Any of a variety of alkaline materials can be used for this
purpose, for example, sodium and potassium hydroxide, sodium
bicarbonate, sodium carbonate, calcium hydroxide, potassium
hydroxide, magnesium hydroxide, ammonia, and some organic alkalies.
Examples of suitable organic alkaline compounds include the
water-soluble soaps of fatty acids such as the alkali metal (e.g.,
sodium, potassium), ammonium or substituted-ammonium (e.g.,
alkanol-amine) salts of saturated or unsaturated fatty acids.
[0079] When sodium hydroxide is used, it is typically present at a
concentration of from about 1.0 to about 2.5% by weight in water.
It will be appreciated that solutions of other alkali agents can be
suitably employed although they will be used in different amounts
or concentrations depending upon solubility, stoichiometry and
nature of the particular alkali employed.
[0080] The chilled oil and alkali solutions are then typically
mixed with gentle agitation. The alkali solution is added until it
forms from about 10 to about 30% by weight, for example, from about
15 to about 25%, of the total mixture. Agitation may be provided by
any suitable means, although rotary mixers operating to provide low
shear and high circulation are preferred. The agitation should be
strong enough to uniformly disperse the alkali solution, but not so
strong that an inseparable emulsion is formed. If high shear mixing
is employed the alkali solution and the oil form a virtually
inseparable emulsion making further separation difficult. The
alkali solution is kept in contact with the oil for a minimum of a
half hour.
[0081] The mixture can then be centrifuged to form a heavy phase
and light phase. The heavy phase contains the fatty acids and
certain other impurities, while the light phase includes the
neutralized oil fraction. Once dried, the oil fraction can be used
in biodiesel production as described herein.
[0082] Alternatively, the oil fractions comprising the fatty acids
can be esterified with an alcohol, such as methanol or ethanol, in
the presence of an acid catalyst. Any strong acid can be used as
catalyst, including hydrochloric acid, sulfuric acid, acidic
zeolites, and polymers with sulfonic acid groups, commonly referred
to Dowex.RTM. and Amberlyst.RTM. catalysts, including Dowex.RTM.50,
for example.
[0083] Another way to deal with oil fractions that include high FFA
concentrations is to filter them through clay, where fatty acid
salts can be intercalated into the clay.
VI. Biodiesel Production
[0084] The methods used for biodiesel production from the used
cooking oil purified using the processes described herein are
similar to conventional transesterification processes used for
virgin cooking oils. However, the processes may vary depending on
the amount of free fatty acids, as well as the water content of the
used cooking oil.
[0085] Biodiesel can be produced in batches or continuous processes
by transesterifying triglycerides such as animal fat or vegetable
oil with lower molecular weight alcohols in the presence of a base
or an acid catalyst. This reaction occurs stepwise, with
monoglycerides and diglycerides as intermediate products. The
relatively large vegetable oil molecule is reduced to about one
third of its original size, lowering the viscosity making it
similar to diesel fuel. The resulting fuel operates similar to
diesel fuel in an engine. The reaction produces three molecules of
an ester fuel from one molecule of vegetable oil.
Transesterification is the process of separating the fatty acids
from their glycerol backbone to form fatty acid esters (FAE) and
free glycerol. The reaction is base-catalyzed, and involves
reacting a triglyceride with an alcohol, which is typically
methanol or ethanol. Transesterification is the most common method
and leads to mono alkyl esters of vegetable oils and fats (i.e.,
biodiesel). The methyl/ethyl ester produced by transesterification
of vegetable oil typically has a high cetane number, low viscosity
and improved heating value compared to those of pure vegetable oil
which results in shorter ignition delay and longer combustion
duration and hence low particulate emissions.
[0086] During transesterification, a triglyceride reacts with a
threefold excess of an alcohol such as ethanol or methanol, and
this alcohol takes the place of the ester linkage to glycerol,
yielding three fatty acid esters of the new alcohol and
glycerol.
[0087] The biodiesel produced by this process is totally miscible,
in any proportion, with diesel derived from crude oil.
VII. Lubricant Production
[0088] In order to manufacture a finished lubricant product from
recovered oil samples, referred to herein as lube base oils, the
lube base oils are compounded. Those of skill in the art can
readily determine how to add additives to a lube base oil, using
conventional blending techniques. These techniques relate to the
order and the rate of additive addition, temperature regime, extent
of mixing, and the like.
[0089] Additives Used in Lubricant Formulations
[0090] Lubricant formulations include lube base oil and one or more
additives. Representative additives include antirust agents,
antioxidant agents, demulsifiers, antifoam agents (also known as
defoamers), viscosity modifiers, pour point depressants, antiwear
agents, seal swell agents, dispersants, detergents, diluent oils
(solvents), and combinations thereof.
[0091] Representative solvents include kerosene, Exxsol D-95, and
biodiesel. Additional solvents include paraffin base, naphthenic
base, asphaltic base, and mixed base oils. Synthetic oils include
polyolefin oils (especially hydrogenated alpha-olefin oligomers),
alkylated aromatics, polyalkylene oxides, aromatic ethers, and
carboxylate esters (especially diesters), among others.
[0092] Representative antioxidants (oxidation inhibitors) reduce
the tendency of base stocks to deteriorate in service, which
deterioration can be evidenced by the products of oxidation such as
sludge and varnish-like deposits that deposit on metal surfaces and
by viscosity growth of the finished lubricant. Such oxidation
inhibitors include, but are not limited to, hindered phenols,
sulfurized hindered phenols, alkaline earth metal salts of
alkylphenolthioesters having about C.sub.5 to about C.sub.12 alkyl
side chains, sulfurized alkylphenols, metal salts of either
sulfurized or nonsulfurized alkylphenols, for example calcium
nonylphenol sulfide, ashless oil soluble phenates and sulfurized
phenates, phosphosulfurized or sulfurized hydrocarbons, phosphorus
esters, metal thiocarbamates, and oil soluble copper compounds as
described in U.S. Pat. No. 4,867,890.
[0093] Representative antioxidants include the Irganox family of
antioxidants, for example, Ciba.RTM. IRGANOX.RTM. 1010, Ciba.RTM.
IRGANOX.RTM. 245 DW, Ciba.RTM. IRGANOX.RTM. 1035, Ciba.RTM.
IRGANOX.RTM. 565, Ciba.RTM. IRGANOX.RTM. 1076, Ciba.RTM.
IRGANOX.RTM. 1425, Ciba.RTM. IRGANOX.RTM. 1098, Ciba.RTM.
IRGANOX.RTM. 1520, Ciba.RTM. IRGANOX.RTM. 1135, Ciba.RTM.
IRGANOX.RTM. 1726, Ciba.RTM. IRGANOX.RTM. 1330, Ciba.RTM.
IRGANOX.RTM. 5057, Ciba.RTM. IRGANOX.RTM. 245, Ciba.RTM.
IRGANOX.RTM. HP 2225, Ciba.RTM. IRGANOX.RTM. B 215, Ciba.RTM.
IRGANOX.RTM. B 612, Ciba.RTM. IRGANOX.RTM. B 225, and Ciba.RTM.
IRGANOX.RTM. 1171.
[0094] Other antioxidants that may be used include sterically
hindered phenols and diarylamines, alkylated phenothiazines,
sulfurized compounds, and ashless dialkyldithiocarbamates.
Non-limiting examples of sterically hindered phenols include, but
are not limited to, 2,6-di-tertiary butylphenol, 2,6 di-tertiary
butyl methylphenol, 4-ethyl-2,6-di-tertiary butylphenol,
4-propyl-2,6-di-tertiary butylphenol, 4-butyl-2,6-di-tertiary
butylphenol, 4-pentyl-2,6-di-tertiary butylphenol,
4-hexyl-2,6-di-tertiary butylphenol, 4-heptyl-2,6-di-tertiary
butylphenol, 4-(2-ethylhexyl)-2,6-di-tertiary butylphenol,
4-octyl-2,6-di-tertiary butylphenol, 4-nonyl-2,6-di-tertiary
butylphenol, 4-decyl-2,6-di-tertiary butylphenol,
4-undecyl-2,6-di-tertiary butylphenol, 4-dodecyl-2,6-di-tertiary
butylphenol, methylene bridged sterically hindered phenols
including, but not limited to,
4,4-methylenebis(6-tert-butyl-o-cresol),
4,4-methylenebis(2-tert-amyl-o-cresol), 2,2-methylenebis(4-methyl-6
tert-butylphenol, 4,4-methylene-bis(2,6-di-tert-butylphenol) and
mixtures thereof as described in U.S Publication No.
2004/0266630.
[0095] Rust inhibitors also include nonionic polyoxyalkylene
polyols and esters thereof, polyoxyalkylene phenols, and anionic
alkyl sulfonic acids.
[0096] Representative demulsifiers include alkyl benzene
sulfonates, polyethylene oxides, polypropylene oxides, esters of
oil soluble acids and the like.
[0097] Defoamers suitable for use in the embodiments may include
silicone oils of suitable viscosity, glycerol monostearate,
polyglycol palmitate, trialkyl monothiophosphates, esters of
sulfonated ricinoleic acid, benzoylacetone, methyl salicylate,
glycerol monooleate, glycerol dioleate, polyacrylates, poly
dimethyl siloxane, poly ethyl siloxane, polydiethyl siloxane,
polymethacrylates, trimethyl-triflouro-propylmethyl siloxane and
the like. The antifoams may be used alone or in combination. The
antifoams may be used in the range of about 0.001 wt % to about
0.07 wt % based on the total weight of the concentrate.
[0098] Viscosity modifiers (i.e., tackifiers) provide viscosity
improving properties. Examples of viscosity modifiers include vinyl
pyridine, N-vinyl pyrrolidone and N,N'-dimethylaminoethyl
methacrylate. Polyacrylates obtained from the polymerization or
copolymerization of one or more alkyl acrylates also are useful as
viscosity modifiers.
[0099] Representative dispersants include ashless type dispersants
such as Mannich dispersants; polymeric dispersants; carboxylic
dispersants; amine dispersants, high molecular weight (i.e., at
least 12 carbon atoms) esters and the like; esterified maleic
anhydride styrene copolymers; maleated ethylene diene monomer
copolymers; surfactants; emulsifiers; functionalized derivatives of
each component listed herein and the like; and combinations and
mixtures thereof. The dispersant may be used alone or in
combination.
[0100] Representative anti-wear agents include sulfur or
chlorosulfur compounds, a chlorinated hydrocarbon compound, a
phosphorus compound, or mixtures thereof Examples of such agents
are amine salts of phosphorus acid, reaction products of alkenes or
alkenoic acids with thiophosphoric acids, chlorinated wax, organic
sulfides and polysulfides, such as benzyldisulfide,
bis-(chlorobenzyl) disulfide, dibutyl tetrasulfide, sulfurized
sperm oil, sulfurized methyl ester of oleic acid sulfurized
alkylphenol, sulfurized dipentene, sulfurized terpene, and
sulfurized Diels-Alder adducts; phosphosulfurized hydrocarbons,
such as the reaction product of phosphorus sulfide with turpentine
or methyl oleate, phosphorus esters such as the dihydrocarbon and
trihydrocarbon phosphate, i.e., dibutyl phosphate, diheptyl
phosphate, dicyclohexyl phosphate, pentylphenyl phosphate;
dipentylphenyl phosphate, tridecyl phosphate, distearyl phosphate
and polypropylene substituted phenol phosphate, metal
thiocarbamates, such as zinc dioctyldithiocarbamate and barium
heptylphenol diacid, such as zinc dicyclohexyl phosphorodithioate
and the zinc salts of a phosphorodithioic acid, as well as
combinations and mixtures thereof.
[0101] In one embodiment the antiwear agent comprises an amine salt
of a phosphorus ester acid. The amine salt of a phosphorus ester
acid includes phosphoric acid esters and salts thereof;
dialkyldithiophosphoric acid esters and salts thereof; phosphites;
and phosphorus-containing carboxylic esters, ethers, and amides;
and mixtures thereof. In one embodiment the phosphorus compound
further comprises a sulfur atom in the molecule.
[0102] In one embodiment the amine salt of the phosphorus compound
is ashless, i.e., metal-free (prior to being mixed with other
components). The antiwear agent can be used alone or in combination
and may be present in an amount of 0.001 wt % to 0.5 wt %, based on
the total weight of the concentrate.
[0103] Pour point depressants, otherwise known as lube oil flow
improvers, lower the minimum temperature at which the fluid will
flow or can be poured. Such additives are well known. Non-limiting
examples of pour point depressant additives which improve the low
temperature fluidity of the fluid are about C.sub.8 to about
C.sub.18 dialkyl fumarate/vinyl acetate copolymers,
polyalkylmethacrylates, alkylphenols and derivatives thereof,
ethylene vinyl acetate copolymers and the like. The pour point
depressant may be used alone or in combination. The pour point
depressant is typically present in an amount of 0.01 wt % to 0.5 wt
%, based on the total weight of the formulation.
[0104] Representative seal swell agents include organo sulfur
compounds such as thiophene, 3-(decyloxy)tetrahydro-1,1-dioxide,
phthalates and the like. The seal swell agents may be used alone or
in combination. The seal swell agents may be present in an amount
of 0.01 wt % to 0.5 wt %, based on the total weight of the
formulation.
[0105] Processes for Producing Lubricants
[0106] The following general procedure can be used to prepare
lubricant formulations using the base oils and additives described
herein:
[0107] Obtain a cleaned container capable of mixing the various
components. Add in a first volume of the lube base oil, with
mixing.
[0108] Making sure the oil is mixed, begin heating the lube base
oil until the temperature reaches a temperature between about 60
and 70.degree. C.
[0109] Add the antioxidant (in this case, AO-L135 (BASF, sold under
the tradename Irganox.RTM. L135), the tackifying additive (in this
case, POL-V570, Controlled Release Technologies) and the pour point
depressant (in this case, PPD-310), and mix the components for a
suitable period of time, for example, between about 1 and 2 hours.
Once the mixture is clear and uniform upon visual inspection,
additional components, such as an anti-wear hydraulic additive
package (in this case, HF-543, HiTEC.RTM.), the anti-wear additive
(in this case, HF-902, HiTEC.RTM.), an odorant (in this case, ODOR1
and a cleaner/degreaser (in this case, GREEN1 Cleaner, sold by
Green1 in Irvine, Calif.) and mix the components for an additional
period of time, for example, between 30 and 60 minutes.
[0110] Add the remaining lube base oil, and mix the components for
another one to two hours.
[0111] Optionally, submit a sample of the resulting lubricant oil
formulation to quality control/quality assurance for analysis.
[0112] A representative set of equipment for producing the
lubricant formulations described herein is shown in FIG. 5. As
shown in FIG. 5, lube base stocks are added to a vessel equipped
with a mixer, and drums/bags with additives are lined up for
addition to the vessel. After the lubricant formulation is
thoroughly mixed, the finished product can be drained out of the
bottom of the vessel (the "lubricant outlet"), optionally filtered
to remove solid impurities and insoluble components, then
dispensed/packaged.
[0113] In one embodiment, the mixing tank has a capacity of around
1000 liters, so that the base oil can be prepared in relatively
small batches. Ideally, the kettle mixer has two sets of blades,
with the bottom set at <10% kettle capacity, and with four to
six blades per set. The capacity of such kettle should be flexible
enough to manufacture both larger and smaller batches (e.g. 2 drums
of 55 gal), and the mixer should be sufficiently powerful to blend
in polymeric and viscous additives, needed for specialty lubricant
manufacture.
[0114] In case quality assurance is performed off-site, it is
advisable to collect specimens of every additive lot that is used,
as well as compounded product batches, and store them for an
appropriate period of time, for example, 2 years or longer.
[0115] Manufactured product should provide consistent technical
performance and meet established specification limits. Accordingly,
it is advisable to compile a set of technical specifications for
the product, and submit the additives and base oil to a quality
assurance team for analysis before compounding, and submit the
product for analysis as well.
[0116] The properties of base oil are crucial to the product
quality, because the additives have only very limited influence on
the oil appearance and phase separation. It can be desirable to
monitor the quality of the base oil in order to obtain the most
appropriate properties of the winterized used cooking oil.
[0117] One representative overall scheme for a Quality Assurance
("QA") system is shown in FIG. 7. As shown in FIG. 7, used cooking
oil is collected, and winterized using the processes described
herein to provide a fraction of oil for use in biodiesel
production, and a fraction of oil for use in lube oil formulations
(i.e., a base oil or a lube base oil), which can be subjected to QA
protocols to confirm their acceptability for the desired uses.
Additives are obtained, and can also be subjected to QA protocols.
The additives (referred to as raw materials) and base oil are
combined, batchwise, to produce a "lube batch." This lube batch can
also be subjected to QA protocols, and if necessary, adjusted or
re-worked. Optionally, once the material is determined to have
satisfied the desired QA protocol, the final lubricant formulation
can be sold.
[0118] As shown in FIG. 7, the QA protocol ideally cover three
sectors: additives, base oils and finished lubricants. Each QA
sector is briefly discussed below.
[0119] QA of Additives
[0120] Usually the additives are supplied along with the
Certificates of Analysis, which indicate the compliance to the most
important requirements for purity, homogeneity and sometimes
performance specifications. Tests can be used to confirm the
identity, as well as the purity, of the material. Visual/odor
inspection, density and viscosity measurements usually are
sufficient. Thin layer chromatography can also be used.
[0121] QA of Winterized Oil
[0122] The consistency of waste oil re-processing and extent of its
winterization determine the quality of the formulated lubricant. In
one embodiment, the QA involves keeping track of how the oil
properties change when key processing parameters are varied. For
example, it can be useful to track one or more of the
following:
[0123] the maximum achieved temperature of the oil in the
processing tank,
[0124] the duration of the oil residence in the processing
tank,
[0125] the amount of sediment retained in the processing tank,
[0126] the amount of bulk oil retained in the processing tank,
[0127] the % vol of clear liquid layer in a sediment sample from
the processing tank after a given time period, such as
approximately 1 week,
[0128] the % vol of sediment in a bulk oil sample from the
processing tank after a given time period, such as 1 week.
[0129] the maximum achieved temperature of the oil in holding
tank
[0130] the duration of the oil residence in the holding tank
[0131] the sediment retained in the holding tank
[0132] the bulk oil retained in the holding tank
[0133] the % vol of clear liquid layer in sediment sample from
holding tank after 1 week
[0134] the % vol sediment in bulk oil sample from holding tank
after 1 week
[0135] the lowest achieved temperature of the oil in the
winterization tank
[0136] the duration of the oil residence in the winterization
tank
[0137] the bulk oil retained in the winterization tank
[0138] the % vol sediment in a bulk oil sample from the
winterization tank after 1 month
[0139] By collecting and reviewing one or more of these parameters,
preferably three or more of these parameters, and, more preferably,
five or more of these parameters, it is possible to optimize
regimes for the oil processing and winterization. In one
embodiment, the data is collected throughout the hottest and
coldest seasons of the operations, e.g. during July and
January.
[0140] Formal QA of winterized oil can include an analysis of the
fatty acid content, which is likely to relate to the precipitate
formation. Relatively high amounts of stearic, palmitic and
trans-fatty acids are usually responsible for increased
sedimentation. Free Fatty Acid (FFA) and Total Acid Number (TAN)
analysis are relevant, because the oil acidity defines lubricant
anticorrosion properties and water incompatibility, as well as
additive solubility and lubricity.
[0141] Although this is not necessarily a measure of lube base oil
performance, it can be relevant to measure oil color, as darker
colored lube base oils tend to be perceived by customers as being
less desirable.
[0142] The viscosity, water content, solidification temperatures
(pour and cloud points), and the like can also be measured.
[0143] QA of Finished Lubricants
[0144] Although faulty products are unusual in lubricant
manufacturing, the kettle blending process is prone to compounder
mistakes, raw material contamination and deviations from the
established procedures. Accordingly, a QA system is ideally
sufficiently reliable to identify problematic batches. For
monitoring the quality of the finished lubricant, it can be
desirable to perform a series of QA tests on every manufactured
batch.
[0145] In case of chainsaw lubricants, the QA of finished product
ideally includes one or more of the following tests:
[0146] Appearance at room temperature (clear, hazy, cloudy,
sediment, etc.)
[0147] Color assessment
[0148] Viscosity at 40.degree. C.
[0149] Cloud point
[0150] Total Acid Number
[0151] Tackiness
[0152] Water rejection
[0153] Density
[0154] To confirm that the lubricity additives and pour point
depressants were properly added, one can use specialized equipment
to identify the presence of these additives either directly (for
example, using chromatographs or spectroscopes) or indirectly
(using lubricity testers or low temperature baths). Because the
presence of lubricity additives can be important, in one
embodiment, these additives are colored before blending with the
oil to assure they are present in the finished product.
[0155] Chain Saw Lubricant Formulations
[0156] In some embodiments, the lube base oils described herein can
be combined with at least one additive to provide finished chainsaw
lubricant compositions. Representative additives include antirust
agents, demulsifiers, antifoam agents, dispersants, detergents,
diluent oils (solvents), and combinations thereof.
[0157] Preferably, chain saw lubricant formulations include at
least six components, namely, a lube base oil as described herein,
a tackifier, a pour point depressant (PPD), an anti-wear (AW)
additive, such as an extreme pressure (EP) antiwear additive, a
rust inhibitor/protector (RP), and an antioxidant.
[0158] A representative formulation includes a lube base oil at
around 80% by weight, a tackifier additive (Functional V-570,
Functional Products, Inc) at around 15% by weight, a pour point
depressant (Functional PD-551, Functional Products, Inc) at around
1.5% by weight, an anti-wear additive (Functional HF-560,
Functional Products Inc) at around 0.9% by weight, an extreme
pressure antiwear additive (Irgalube TPPT, BASF (formerly Ciba)) at
around 0.9% by weight, a rust protector (DCHA (Di Cyclo Hexyl
Amine), BASF) at around 0.9% by weight, and an antioxidant (Irganox
L-135, BASF (formerly Ciba) at around 0.9% by weight, wherein all
weight percentages are based on total weight of the
formulation.
[0159] The V-570 additive in this embodiment is used at a 15% treat
rate in the chainsaw lubricant. V-570 is a composition including a
proprietary polymer in a vegetable oil base. The content of its
active material (polymer) is higher than 1% wt.
[0160] The amounts of active materials out of the other additives
in the formulation are typically below 1% wt. In one embodiment,
the additives are ashless, so do not significantly affect the
safety parameters of the chainsaw lubricants. Their toxicity is
relatively low, except DCHA that is essentially completely
converted into the soap, when blended with the re-processed
oil.
[0161] The additives serve defined functions, and improve the
performance of the lubricants, including the chainsaw lubricants.
The function of the various additives is shown in the following
table:
TABLE-US-00001 TABLE 1 Additives and Their Function. Representative
Component Components Function in chainsaw lubricant BASE OIL
Basestock - acts as a lubricant itself, although low (first
portion) quality. Without additives might produce heavy deposits,
fast chain wear AO ADD Irganox L-135 Antioxidant - inhibits
degradation of oil and Irganox 1010 additives at high temperatures
due to friction. Irganox L-109 Prevents deposit formation. TACK ADD
Functional V-570 Tackifier - adds stringiness (tackiness) to the
oil, Functional V-584 not letting it drip or fly off the chain
during LZ 7612 operation. Concurrently increases oil viscosity
Polymer Functional V-508 Thickener - increases oil viscosity for
better film (only in Functional V-508S strength, separating the
chain and the bar. Better alternative control of the flow when
pouring out of container formulation) onto the chain. Reduced need
for tackifier additives. PPD Functional PD-551 Pour point
depressant - inhibits oil solidification at Functional PD-555 low
temperatures short term. Does not prevent the LZ-7671A
solidification long term. Slightly increases Viscoplex 10-310
viscosity. Viscoplex 10-171 AW ADD Functional HF-560 AntiWear
additives - prevent the chain, bar, Functional HF-500 sprocket and
other moving metal surfaces from LZ-7653 rapid wear under
mediumload and elevated HiTEC 543 temperature conditions. HiTEC
2590A EP ADD Irgalube TPPT Extreme Pressure additives - reduce
friction under VanLube 0902 heavy loads, assuring there is no major
damage to Additin RC 2317 the metal surface. Might protect the
chain from losing sharpness when hitting metal wire, nails, etc. RP
ADD DCHA Rust Protection additives - partially neutralize the
Additin RC 3760 free acids and provide corrosion inhibition. DCHA
is also effective in vapor phase and it makes the oil more
resistant to microbial attacks. COLOR only in alternative Colorant
- improves appearance and differentiates ADD formulation the
product from competitors ODOR ADD only in alternative Odorant (odor
mask) - suppresses potentially formulation objectionable smell,
improves customer acceptance BASE OIL Basestock - same functions.
In compounding, the (second portion) second portion reduces the
kettle heating and stirrer energy consumption.
[0162] In the table shown above, base oil is shown twice. In one
embodiment of a method for preparing the lube base oils, the
additives are added to a first portion of base oil, and after the
components are thoroughly mixed, a second portion of base oil is
added, and the composition is re-mixed.
[0163] In selecting the most effective additives several types of
tests were carried out. The performance of the additives varied
significantly, despite belonging to the same category. Most likely
the base oil effect on the additives was more significant than
anticipated. The best performing additives were identified by
running the bench tests and included into the formulation. Their
treat rates were also balanced accordingly. If necessary, most of
these additives can be replaced with others, however, not always at
1:1 ratio.
[0164] In one embodiment, the lube base oil is used to prepare a
chainsaw formulation. The table below shows the addition of
conventional chainsaw lubricant additives to a lube base oil
obtained using the process described herein. The formulation is
sufficient to prepare three 55 gallon drums.
[0165] Green1 is a 100% bio-based, non-toxic, non-hazardous, green
degreaser/cleaner, which includes a proprietary colloidal blend of
100% bio-based nanoparticles.
[0166] AO-L135, also known as Irganox.RTM. L135 antioxidant, has
the following formula:
##STR00001##
[0167] PPD-310 is a pour point depressant (also known as EX.RTM.
10-310).
[0168] HF-543 (also known as HiTEC.RTM. 543), is an ashless
anti-wear hydraulic additive package.
[0169] V570 (Tackifier V-570, sold by Functional Products, Inc. in
Macedonia, Ohio, is a proprietary polymer dissolved in a
biodegradable vegetable oil, where the weight percentage of polymer
to oil is around 10%)
[0170] The contents of a representative batch of a chainsaw
lubricant is shown in the following table.
TABLE-US-00002 TABLE 2 Additive % wt Gallons Base Oil 18.98 31.11
(first portion) AO-L135 1 1.77 V570 6 10.52 PPD-310 1 1.73 HF-543 1
1.71 Van Lube 0902 2 3.39 Odorant* 0.01 0.02 GREEN1* 0.01 0.02 Base
Oil 70 114.73 (second portion) total 100 165 *GREEN1 (a cleaner)
and odorants are optional components.
[0171] The formulation shown above is tabulated in the order of
addition during the compounding process, which is why there are two
separate amounts of lube base oil listed.
[0172] Mould Release Fluid Formulations
[0173] The re-processed oil, in particular, the lube base oils,
described herein can be used to produce mould-release fluids. Mould
release oil compositions include the lube base oil described
herein, an organic solvent, such as kerosene, a tackifier, a rust
inhibitor, an antioxidant, and optionally a demulsifier, and/or an
odorant. A representative formulation is listed in the table
below.
TABLE-US-00003 TABLE 3 Representative Mould Release Oil
Formulations Representative Components or Component Suppliers
Mineral solvent Exxsol D-95 or 0 50 kerosene Biodiesel 30 0
Re-processed oil 50 30 Tackifier Functional V-570 7 7 (Functional
Products, Inc.) Rust inhibitor Rhein Chemie 7 7 Antioxidant Irganox
1 1 Odorant 0.1 0.1 Demulsifier 2 2
[0174] It is believed that the relatively high free fatty acid
content in the re-processed oil will not be a problem for mould
release fluids, particularly if a rust protective additive, such as
DCHA, is incorporated into the formulation.
[0175] Cutting Oils
[0176] Where a sample of used cooking oil the lube base oil has
excessive sediment, it may not be suitable for use in manufacturing
cutting oils. The reason is largely that if customers find
significant amounts of the residue in their cutting oil, they might
assume that the residue is precipitated performance additives,
rather than pasty residues from the used cooking oil itself.
Accordingly, it is desirable to use uniform and clean base oils to
produce cutting oils.
[0177] The processes described herein allow one to produce high
quality winterized lube base oils that include relatively low
sediment concentration. Examples of cutting oil additives include
Oil Conditioner L, an antioxidant blend sold by Commonwealth Oil,
Oil Conditioner M, a phosphorous and antioxidant spike, sold by
Commonwealth Oil, and Oil Conditioner N, a tank side sulfurized fat
performance additive, also sold by Commonwealth Oil, TRIM.RTM.
OSFA, a lubricity additive for straight cutting oils, DARL
concentrate (Fiske Brothers Refining Company, AZ 1371, a
sulfur-containing cutting oil additive recommended for machining
ferrous as well as non-ferrous metals (Addizol), emulsifiers such
as Emulsifier P-15, Emulsifier P-25, Emulsifier P-35, and
Emulsifier P-45 (Nipro Technologies Ltd.).
[0178] It is believed that lube base oils for use in cutting oils
can include relatively high fatty acid concentrations, and also
tolerate relatively high water contents, since it is possible to
reduce the acidity by adding materials with high alkalinity, such
as DCHA.
[0179] Hydraulic Fluids
[0180] Uniform and clean base oils are very important for producing
hydraulic fluid. In case high quality winterized oil is produced,
this application might become more likely to be successful.
[0181] Most lubricant additive suppliers provide additive packages
for vegetable oil based hydraulic fluids. Typically, hydraulic
fluids include an antioxidant, an anti-wear additive in a range of
from about 0.5 to 5% by weight, a rust-proofing additive, a pour
point depressant additive, in a range of between about 0.5 and 1.5%
by weight, more typically around 1% by weight, and a defoamer,
typically at a very low concentration, for example, around
0.005-0.05%. In such hydraulic fluid composition, all weight
percentages are based on total weight of the composition.
[0182] Relatively high fatty acid content can adversely impact
hydraulic fluid formulations. Additives, which might be required to
improve the rust protection of the lubricant, might be affected
negatively by this acidity. That is, one such additive is DCHA
(dicyclohexylamine), which is a base, and bases react with
acids.
[0183] Therefore, if the lube base stock includes a higher fatty
acid concentration than the range described above, the fatty acid
concentration may be lowered, for example, by subjecting the lube
base stock to a neutralization step as described above, or by
filtering the base stock through clays. The intercalation of salts
of fatty acids into clays such as kaolinite is known in the art,
for example, as described in Sidheswaran et al., "Intercalation of
salts of fatty acids into kaolinite," Clays and Clay Minerals,
38(1):29-32 (1990).
[0184] Effectiveness of Lubricant Additives in Re-Processed Base
Oils
[0185] The specific formulations of the chainsaw lubricants
described above include components from two suppliers only,
Functional Products and BASF, though additives from other
companies, such as Lubrizol, Evonik, Afton Chemical, RT Vanderbilt
and Rhein Chemie can also be used.
[0186] Viscosity Studies
[0187] Vegetable oils are known for relatively uniform viscosities
and re-processed oil confirmed that rule. Therefore, relatively
high treat rates of polymers are necessary in order to increase
their viscosity. Several thickeners and tackifiers were tested for
their effectiveness. Functional V-570 (Functional Products) was
selected for the specific formulation described herein because it
provides both tackiness and higher viscosity. Typically, the
viscosity increases exponentially with addition of more viscous
additives. For confirmation, the viscosity dependence on the
contents of V-570 was established from the experimental data, as
shown in FIG. 6. The data showed that the viscosity dependence on
the tackifier contents met the theoretical expectations, so the
viscosity can be tailored to individual specifications by using the
chart shown in FIG. 6 and providing the appropriate amount of the
thickener/tackifier.
[0188] Low Temperature Studies
[0189] Similarly to viscosity, the trends of pour point depression
(PPD) were studied.
[0190] The amount of PPD additives is expected to reach optimal
performance at about 1% wt. treatment level, though experimental
data (FIG. 8) showed somewhat different performance. Lube base oil
formulations with different levels of tackifier (10, 15, and 20% by
weight Functional V-570) with varying amounts of PPD (Functional
551 at 1, 1.5, and 2% by weight) were evaluated. Pour points
continued to be depressed as the concentration of the PPD additives
was increased to 2 percent by weight.
[0191] Low temperature solidification depends on both the pour
point depressant and the tackifier concentrations. The amount of
tackifier in these formulations is relatively high, and,
accordingly, the crystallization kinetics, in particular the
nucleation, can be affected significantly by the polymer chains in
the tackifiers. The correlation also suggests that the lubricity
additive might have an influence on crystallization as well.
VIII. Representative Process and Plant Design
[0192] Representative models for plants capable of winterizing used
cooking oil are shown in FIGS. 2 and 3, which represent separate
embodiments of a plant capable of carrying out the winterization
processes described herein.
[0193] In both embodiments, a crude oil supply (also referred to
herein as a waste oil supply) is sent to a processing tank. After
the oil is cooled, and then allowed to warm to room temperature,
crystalline impurities settle to the bottom of the processing tank.
These can be drained through a valve, as shown, or, alternatively,
the oil could be passed through a centrifuge and the solids
collected in a centrifuge back, or the oil could be decanted from
the solids.
[0194] Oil in the processing tank is then passed through intake
piping to transfer the material to a holding tank, and allowed to
further separate. The upper fraction is removed through intake
piping, and a portion of the oil is collected for use as a
feedstock for biodiesel production. Another portion of the oil is
moved to a winterization tank. A lower fraction of oil including
solid material is removed, and sent to the processing tank, where
solids settles to the bottom and can be collected apart from the
oil.
[0195] In the winterization tank, the oil is chilled, and allowed
to form a precipitate. An oil fraction including the precipitate is
also sent to the processing tank, and the oil that remains is
passed through an intake valve and collected for use as a lube base
stock.
[0196] In the embodiment shown in FIG. 3, the set up includes two
winterization tanks. An oil fraction including a precipitate is
removed from the bottom of the processing tank, and an intake valve
is used to transfer the oil to a first holding tank. From there,
precipitate is sent back to the processing tank, and the oil is
removed from the top of the processing tank through an intake
valve. A first portion of the oil is collected for use in producing
biodiesel, and the remaining oil is passed on to two winterization
tanks, where it is allowed to further settle. Solid precipitates
resulting from the winterization step are passed to the processing
tank, where they are collected, and the oil at the top is removed
from both tanks through intake valves and collected for use as a
base oil for lubricants.
[0197] When oil, such as used cooking oil, is allowed to separate,
it tends to form at least the following layers--an upper layer of
"sheen," a bulk phase, a cloudy phase, a slurry phase, and a paste
phase.
[0198] In order to remove these molecules, it is necessary to cool
or refrigerate the oil initially, forcing their crystallization.
Then the cold oil can be allowed to thaw, which leads to migration
of more fluid molecules to the top of the oil and sedimentation of
solid molecules on the bottom. Filtration can be exercised at that
stage as well. Such process is typically referred to as oil
winterization. Its suitability for the waste oil re-processing is
discussed in detail below.
[0199] The longer the used cooking oil is stored, the better the
sediment ("paste phase") separates from the top layers. Typically,
this is called `oil winterization` in the food industry.
[0200] In a typical winterization process, oil is stored stagnant
in storage tanks and pumped out from the top. Various thermal
regimes are used, but generally it is considered that better
winterization is achieved with lower the temperature of the storage
tank and prolonged storage durations.
[0201] The oils are chilled, typically with gentle agitation, which
causes higher melting fractions to precipitate. The higher melting
fractions typically include waxes and fatty acids.
[0202] Filtration of the Re-Processed Oils, Lubricants and/or
Biodiesel Formulations
[0203] In one embodiment, the reprocessed oils, biodiesel fuel,
and/or lubricant formulations are filtered, preferably through a
filter with a pore size of between approximately 5 and 50 microns,
more preferably, between approximately 10 and 20 microns, to remove
solid impurities.
[0204] The features and advantages of the present disclosure will
be more fully apparent with reference to the following non-limiting
examples.
Example 1
Initial Winterization Step
[0205] A series of samples of used cooking oil was obtained, and
the oils were stored for various periods of times. The appearance
and volumetric extent of phase separation is shown below in Table
4.
TABLE-US-00004 TABLE 4 sample Age, Bulk phase, Cloudy Slurry Pasty
code days color phase phase residues 1EC 480 Clear light <10%
vol. None None amber hazy amber 2EC 480 Clear light <10% vol.
~2% vol ~0.02% amber hazy amber light vol. sediment particles 3EC
16 Clear medium <5% vol. 8% vol. 3% vol. amber hazy amber heavy
thick paste sediment 4EC 16 Clear medium <5% vol. 5% vol. 4%
vol. amber hazy amber heavy thick paste sediment 5EC 4 Hazy medium
Same as bulk 0.5% vol. 0.5% thick amber phase heavy paste sediment
6EC 4 Hazy medium Same as bulk Same as 1% thick amber phase paste
paste 7EC 2 Hazy medium Same as bulk None <0.1% amber phase
light paste 8EC 2 Hazy medium Same as bulk None <0.1% amber
phase light paste 9EC 4 Hazy medium Not n.d. n.d. amber determined
10EC 4 Hazy medium n.d. n.d. n.d. amber
[0206] This data shows that upon longer term storage, it is
possible to separate the oil into various layers. While not wishing
to be bound to a particular theory, it is believed that the thermal
history, i.e. cooling and heating regimes (temperature intervals,
durations, rates) can have an impact on the appearance of the
oil.
[0207] Immediately after arriving, the samples of 7EC (which was
filtered) and 8EC (which was unfiltered) were each poured into two
test tubes. All of them appeared equally hazy without any bottom
sediment. One set was cooled to +5.degree. C. overnight, while the
other was left at room temperature (20.degree. C.). After 16 hrs,
the oils in the refrigerated test tubes were frozen. The test tubes
were taken out, melted at room temperature and stored together with
the other two samples, which always stayed at room temperature. The
samples started forming a clear layer on the top and heavy residues
on the bottom, with the hazy phase in the middle. The observations
were recorded for two weeks, as shown in FIG. 4. FIG. 4 shows that
there was an absence of pasty residues in refrigerated samples,
whereas the room temperature samples 7EC RT and 8EC RT produced
significant pasty residue. The refrigerated samples 7EC cold and
8EC cold formed a relatively uniformly cloudy bulk phase, which was
slowly receding to the bottom. On the top, a phase of clear oil
formed and kept expanding much more rapidly, compared to RT
samples.
[0208] Those samples not cooled (i.e., stored at room temperature)
samples could not consistently produce sizeable clear phase on the
top for more than a week. Apparently, after initial clarification,
some other molecules would begin crystallizing and make the fluid
cloudy. The samples were stored on the bench of an air conditioned
laboratory, therefore, some temperature fluctuations may have had
an influence on the sample appearance. Nevertheless, refrigerated
samples clarified much faster than RT samples.
[0209] The results suggest that the samples, even after about a
week of storage, filtration has little beneficial effect on
cloudiness of oil or its pasty residue formation tendencies. To the
contrary, during the first 4 days the non-filtered sample 7EC RT
was forming the clear layer and pasty residue faster than filtered
sample 8EC RT. This can also be said about the clear phase
formation of 7EC cold sample with respect to 8EC cold. While not
wishing to be bound to a particular theory, it is believed that
during filtration, the crystal seeds were removed, and it therefore
took longer for the filtered samples to separate the precipitates.
The dynamics of forming a cloudy phase changed when oil samples 9EC
and 10EC were stored at room temperature. The room temperature
samples were not frozen before storage, whereas the "cold" samples
were refrigerated to about +5.degree. C. for about 16 hrs before
storing at room temperature. Oil samples 9EC and 10EC followed a
somewhat different scenario in terms of sediment formation.
Pre-Filtered oil (10EC) appeared to separate somewhat faster than
9EC. However, these oils were received 4 days after the
manufacturing, compared to 2 days for 7EC and 8EC. In the meanwhile
unknown temperature fluctuations could have taken place.
[0210] These observations lead to the conclusion that the
re-processed oils contain a lot of molecules that are bound to form
crystals and precipitate. In order to remove these molecules, it is
necessary to cool or refrigerate the oil initially, forcing their
crystallization. Then, the cold oil can be allowed to thaw, which
leads to migration of more fluid molecules to the top of the oil
and sedimentation of solid molecules on the bottom. Filtration can
be exercised at that stage as well. This type of process is
typically referred to as oil winterization, but winterization is
typically performed on virgin oil rather than on used cooking oil.
The suitability of winterization for waste oil re-processing is
discussed in detail below.
[0211] In any event, significant phase separation was evident in
samples 3EC, 4EC, 5EC, 6EC, 7EC, 8EC, 9EC and 10EC. Because
sediment formation would be problematic in most lubricant
applications, including hydraulic fluids, chainsaw lubricants,
mould release fluids or cutting oils, the oils were subjected to
further steps to minimize sediment formation.
Example 2
Comparison to Competitive Products
[0212] The properties of the chainsaw formulation described above
were compared with those of several commercially-available chainsaw
lubricants. Key lubricating properties were selected, including the
tackiness, which is very important for chainsaw lubricants. Two
purchases of the same brand (Power Care) were made in Home Depot,
one in Pittsburgh (CAREP) and another in State College, Pa.
(CARES). Other samples represented different brands. Arborol
chainsaw lubricant (ARBOR), produced by Oregon Blount Inc., is
designed to serve as water-dilutable chainsaw fluid, recommended
ratio 5:1. It was tested as is, however, without any dilution. The
test results are shown in the table below.
TABLE-US-00005 TABLE 5 Comparison of key parameters of competitive
chainsaw lubricants Vis- Lu- cosity Pour bricity* Acidity Trade-
cSt at point WSD, mgKOH/ Tack- Lubricant name 40*C *C mm g iness
Instant 120 -20 0.42 14 Good Compo- sition CARES Power 35.6 -33
0.54 ~0 Poor Care, Home Depot ECHO Echo 141.1 -19 0.57 ~0 Good
Premium Home Depot HQVAR Husqvarna 141.5 -22 0.50 ~0 Good Premium
PSEL Pro Select 90.7 -27 0.49 ~0 Satisfact. Lowes POUL Poulan,
139.4 -23 0.53 ~0 Satisfact. Wal-Mart CAREP Power 153.2 -19 0.50 ~0
Very Care, good Pittsburgh ARBOROL Oregon, 139.8 -22 0.68 -- None
Water Dilutable *Four-ball wear scar diameter.
[0213] Since Arborol is designed for water-dilutable application,
its viscosity and tackiness were not included into the comparative
study. CARES lubricant was clearly very different from others,
therefore, its performance was not considered for comparison
either.
[0214] Nevertheless, the results for the formulation disclosed
above either appear similar to other lubricants or exceed their
performance. The viscosity is higher than that of Power Select and
sufficiently similar to other brands. Pour point performance is
similar as well. Tackiness is more pronounced than that of Echo
Premium or Husqvarna Premium.
[0215] Particularly clear benefits are demonstrated in the
lubricity aspects. Other lubricants demonstrated much more
pronounced wear. It must be noted, that zero-wear is considered
when Wear Scar Diameter (WSD) is equal to 0.34 mm. Therefore, the
margin of advantage for the formulation described herein is much
more pronounced. Also, the lubricity testing conditions are
somewhat more severe than typical and include higher temperatures
and more damaging speeds between moving surfaces. The relatively
high fatty acid content did not appear to cause any corrosive wear.
The free fatty acids appear to have contributed to the lubricity,
but the levels are ideally kept low.
[0216] Vegetable oil based chainsaw lubricants tend to have lower
stability than those based on mineral oil. For this reason, it may
be desirable to add high molecular weight antioxidants.
[0217] Modifications and variations of the present disclosure
relating to a fuel additive composition and an alternative fuel
derived from the composition will be obvious to those skilled in
the art from the foregoing detailed description.
* * * * *