U.S. patent application number 14/294132 was filed with the patent office on 2015-12-03 for fatty acid reduction of feedstock and neutral and acidic alkyl ester.
This patent application is currently assigned to BLUE SUN ENERGY, INC.. The applicant listed for this patent is Blue Sun Energy, Inc.. Invention is credited to Kerry STALLER.
Application Number | 20150344797 14/294132 |
Document ID | / |
Family ID | 54699621 |
Filed Date | 2015-12-03 |
United States Patent
Application |
20150344797 |
Kind Code |
A1 |
STALLER; Kerry |
December 3, 2015 |
FATTY ACID REDUCTION OF FEEDSTOCK AND NEUTRAL AND ACIDIC ALKYL
ESTER
Abstract
Processes and compositions reduce free fatty acid (FFA) in oils
and fats and in neutral or acidic alkyl ester. The oils and fats or
alkyl ester is heated to temperatures from 90.degree. F. to
150.degree. F., and lower numbered alcohol and dilute caustic are
added. The mixture is stirred moderately, and allowed to settle
into two phases--a FFA phase and a second low FFA phase, containing
either oils and fats or alkyl ester. The two phases are separated.
The recovery of both glycerin and lower numbered alcohols is
increased. Some compositions for reducing FFA comprise lower
numbered alcohol and dilute caustic. The processes and compositions
reduce FFA levels to meet fuel standards.
Inventors: |
STALLER; Kerry; (Garrett,
IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Blue Sun Energy, Inc. |
Wheat Ridge |
CO |
US |
|
|
Assignee: |
BLUE SUN ENERGY, INC.
Wheat Ridge
CO
|
Family ID: |
54699621 |
Appl. No.: |
14/294132 |
Filed: |
June 2, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62006017 |
May 30, 2014 |
|
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|
Current U.S.
Class: |
44/389 ;
252/183.11; 252/183.13 |
Current CPC
Class: |
C10L 2290/06 20130101;
Y02P 20/582 20151101; C11C 3/10 20130101; C10L 2290/08 20130101;
Y02E 50/13 20130101; C10L 2290/24 20130101; C10L 2270/026 20130101;
C10L 1/02 20130101; C11C 1/08 20130101; C11C 1/103 20130101; C10L
1/026 20130101; C10L 2200/0476 20130101; C10L 2290/544 20130101;
Y02E 50/10 20130101; C11C 3/003 20130101 |
International
Class: |
C10L 1/02 20060101
C10L001/02 |
Claims
1. A process for refining, the process comprising: providing a
first mixture comprising free fatty acid, alkyl ester, and mixed
fatty glycerides, wherein the amount of mixed fatty glycerides is
no more than 5% wt/wt; providing lower numbered alcohol; providing
dilute caustic; and, adding the lower numbered alcohol and the
dilute caustic to the first mixture resulting in a second
mixture.
2. The process of claim 1, wherein the first mixture further
comprises glycerin, the process further comprising separating
glycerin from the first mixture.
3. The process of claim 2 further comprising centrifuging the first
mixture prior to separating glycerin from the first mixture.
4. The process of claim 1 further comprising heating the first
mixture to a temperature from 90 degrees F. to 150 degrees F.
5. The process of claim 1 further comprising heating the first
mixture to a temperature from 120 degrees F. to 150 degrees F.
6. The process of claim 1 further comprising heating the first
mixture to a temperature from 140 degrees F. to 150 degrees F.
7. The process of claim 4 wherein the first mixture is heated to
temperature before the lower numbered alcohol and the dilute
caustic are added to the first mixture.
8. The process of claim 7 further comprising agitation of the
second mixture.
9. The process of claim 8 wherein the agitation is a low-shear
mixing.
10. The process of claim 9 further comprising allowing the second
mixture to settle into a first phase upper component and a second
phase lower component.
11. The process of claim 10 wherein the settling occurs at
temperature.
12. The process of claim 10 wherein the settling occurs at room
temperature.
13. The process of claim 9 wherein the second mixture settles into
a first phase upper component and a second phase lower
component.
14. The process of claim 11 wherein the first phase comprises alkyl
ester, and the second phase comprises alcoholic aqueous soap.
15. The process of claim 11 further comprising separating the first
phase from the second phase.
16. The process of claim 1 wherein the first mixture is
neutral.
17. The process of claim 1 wherein the first mixture is acidic.
18. The process of claim 1 wherein the lower numbered alcohol is
selected from a group comprising: methanol, ethanol, propanol,
isopropanol, butanol, isobutanol, propylene glycol, ethylene
glycol, and butylene glycol.
19. The process of claim 1 wherein the dilute caustic is selected
from a group comprising: NaOH and KOH.
20. The process of claim 1 wherein the lower numbered alcohol and
the dilute caustic are added simultaneously.
21. The process of claim 1 wherein the lower numbered alcohol and
the dilute caustic are added sequentially.
22. The process of claim 21 wherein the lower numbered alcohol is
added before adding the dilute caustic.
23. The process of claim 15 wherein: the amount of dilute caustic
provided is from stoichiometric to the amount of free fatty acid in
the first mixture to 20% excess of the stoichiometric amount; the
concentration of the dilute caustic provided is from 2% to 15%
wt/wt; and, the amount of lower numbered alcohol provided is from
1% to 20% wt/wt.
24. The process of claim 15 wherein: the amount of dilute caustic
provided is from stoichiometric to the amount of free fatty acid in
the first mixture to 10% excess of the stoichiometric amount; the
concentration of the dilute caustic provided is from 3% to 6%
wt/wt; and, the amount of lower numbered alcohol provided is from
2% to 5% wt/wt.
25. The process of claim 15 wherein: the amount of dilute caustic
provided is from stoichiometric to the amount of free fatty acid in
the first mixture to 5% excess of the stoichiometric amount; the
concentration of the dilute caustic provided is from 4% to 5%
wt/wt; and, the amount of lower numbered alcohol provided is from
2.5% to 3.5% wt/wt.
26. The process of claim 15 wherein the second mixture settling
into a first phase upper component and a second phase lower
component is achieved by centrifuging the second mixture.
27. The process of claim 15 wherein the separating comprises
removing the lower component from second mixture.
28. The process of claim 15 wherein the separating comprises
decanting the upper component from the second mixture.
29. The process of claim 27 wherein the lower component comprises
alcoholic aqueous soap.
30. The process of claim 29 further comprising reacting acid with
the alcoholic aqueous soap.
31. The process of claim 30 wherein the acid is selected from a
group comprising: hydrochloric acid, acetic acid, citric acid,
phosphoric acid, sulfuric acid, and methanesulfonic acid.
32. The process of claim 30 further comprising recovering free
fatty acids formed by the reaction.
33. The process of claim 30 further comprising removing alcoholic
water.
34. The process of claim 15 wherein the separating comprises
removing the upper component from the second mixture and wherein
the removed upper component comprises a third mixture.
35. The process of claim 34 wherein the third mixture comprises
alkyl ester having total acid number less than or equal to 0.5.
36. The process of claim 35 further comprising: washing the third
mixture with soft water to form a resultant mixture, wherein the
resultant mixture comprises soap water and wet ester; and, removing
the soap water from the resultant mixture.
37. The process of claim 35 further comprising removing residual
lower numbered alcohol from the third mixture to form a fourth
mixture.
38. The process of claim 37 wherein the fourth mixture comprises a
purified alkyl ester, and trace amounts of monoglycerides, soap,
residual lower numbered alcohol.
39. The process of claim 38 further comprising washing the fourth
mixture with soft water resulting in a fifth mixture, wherein the
fifth mixture comprises two components.
40. The process of claim 39 wherein the fifth mixture comprises a
wet ester component and a soap water component.
41. The process of claim 40 further comprising removing the soap
water component from the fifth mixture.
42. The process of claim 41 further comprising: removing the wet
ester component from the fifth mixture; and, drying the wet ester
component.
43. The process of claim 41 further comprising adding acid to the
removed soap water component to form a sixth mixture.
44. The process of claim 43 wherein the acid is selected from a
group comprising hydrochloric acid, acetic acid, citric acid,
phosphoric acid, sulfuric acid, and methanesulfonic acid.
45. The process of claim 43 wherein the sixth mixture comprises
re-formed fatty acids and waste water, the process further
comprising recovering the free fatty acids.
46. The process of claim 45 further comprising removing the waste
water from the sixth mixture.
47. A composition for refining, the composition comprising: a lower
numbered alcohol, wherein the lower numbered alcohol is selected
from a group comprising: methanol, ethanol, propanol, isopropanol,
butanol, isobutanol, propylene glycol, ethylene glycol, and
butylene glycol; a dilute caustic, wherein the dilute caustic is
selected from a group comprising NaOH and KOH; and a crude
biodiesel product, wherein the crude biodiesel product comprises:
free fatty acid at a concentration of not more than 10% wt/wt;
monoglycerides at a concentration of not more than 5% wt/wt;
glycerin at a concentration of not more than 1% wt/wt; alcohol at a
concentration of not more than 10% wt/wt; and alkyl ester at a
concentration of not more than 95% wt/wt.
48. The composition of claim 47 wherein the crude biodiesel product
comprises products of transesterification of triglycerides.
49. The composition of claim 47 wherein the crude biodiesel product
comprises products of combined esterification/transesterification
reactions.
50. The composition of claim 47 wherein: the amount of the dilute
caustic is from stoichiometric to the amount of free fatty acid in
the crude product to 20% excess of the stoichiometric amount; the
concentration of the dilute caustic is from 2% to 15% wt/wt; and
the amount of lower numbered alcohol is from 1% to 20% wt/wt.
51. The composition of claim 47 wherein: the amount of the dilute
caustic is from stoichiometric amount to the amount of free fatty
acid in the crude product to 10% excess of the stoichiometric
amount; the concentration of the dilute caustic is from 3% to 6%
wt/wt; and the amount of lower numbered alcohol is from 2% to 5%
wt/wt.
52. The composition of claim 47 wherein: the amount of the dilute
caustic is from stoichiometric to the amount of free fatty acid in
the crude product to 5% excess of the stoichiometric amount; the
concentration of the dilute caustic is from 4% to 5% wt/wt; and the
amount of lower numbered alcohol is from 2.5% to 3.5% wt/wt.
53. A composition for reducing free fatty acid, the composition
comprising: a lower numbered alcohol, a dilute caustic; and,
wherein: the lower numbered alcohol is selected from a group
comprising: methanol, ethanol, propanol, isopropanol, butanol,
isobutanol, propylene glycol, ethylene glycol, and butylene glycol;
the dilute caustic is selected from a group comprising: NaOH and
KOH.
54. The composition of claim 53 further comprising at least one
feedstock, wherein the feedstock is selected from a group
comprising: distiller's corn oil, castor oil, soybean oil, jatropha
oil, algae oil, yellow grease, brown grease, lard, and beef
tallow.
55. The composition of claim 53 further comprising a crude product
of combined esterification/transesterification of triglycerides,
wherein the crude product comprises: free fatty acid at a
concentration not more than 10% wt/wt; monoglycerides at a
concentration not more than 5% wt/wt; alcohol at a concentration
not more than 10% wt/wt; and alkyl ester at a concentration not
more than 95% wt/wt.
56. The composition of claim 53 wherein the crude product further
comprises glycerin at a concentration not more than 1% wt/wt.
57. The composition of claim 55 wherein: the amount of the dilute
caustic is from stoichiometric to the amount of free fatty acid in
the crude product to 20% excess of the stoichiometric amount; the
concentration of the dilute caustic is from 2% to 15% wt/wt; and
the amount of lower numbered alcohol is from 1% to 20% wt/wt.
58. The composition of claim 55 wherein: the amount of the dilute
caustic is from stoichiometric to the amount of free fatty acid in
the crude product to 10% excess of the stoichiometric amount; the
concentration of the dilute caustic is from 3% to 6% wt/wt; and the
amount of lower numbered alcohol is from 2% to 5% wt/wt.
59. The composition of claim 55 wherein: the amount of the dilute
caustic is from stoichiometric to the amount of free fatty acid in
the crude product to 5% excess of the stoichiometric amount; the
concentration of the dilute caustic is from 4% to 5% wt/wt; and the
amount of lower numbered alcohol is from 2.5% to 3.5% wt/wt.
60. A composition for refining, the composition comprising alkyl
ester and alcoholic aqueous soap.
61. The composition of claim 60 further comprising two
non-emulsified phases, wherein the first phase comprises the alkyl
ester, and the second phase comprises the soap.
62. The composition of claim 61 wherein the first phase further
comprises soap, free fatty acid, glycerin, alcohol, monoglycerides,
wherein the amount of: free fatty acid is from 0.1% to 0.3% wt/wt;
glycerin is not detectable; alcohol is from 1% to 2% wt/wt;
monoglycerides is no more than 1.5% wt/wt; and, alkyl ester is at
least 94% wt/wt.
63. The composition of claim 61 wherein the second phase further
comprises alkyl ester, glycerin, wherein the amount of alkyl ester
is no more than 10% wt/wt, and the amount of glycerin is no more
than 2% wt/wt.
64. A composition for refining, the composition comprising alkyl
ester, soap, free fatty acid, glycerin, and alcohol, wherein the
amount of: free fatty acid is from 1.75% to 2.75% wt/wt; glycerin
is from 0.05% to 0.15% wt/wt; alcohol is from 1% to 2% wt/wt; and,
alkyl ester is at least 93% wt/wt.
65. The composition of claim 64 wherein the amount of the alkyl
ester is from 85% to 97% wt/wt.
66. The composition of claim 64 wherein the concentration of: free
fatty acid is not more than 4% wt/wt; glycerin is not more than
0.5% wt/wt; alcohol is not more than 3% wt/wt; and, alkyl ester is
at least 85% wt/wt.
67. A process for reducing free fatty acid in a parent oil, the
process comprising: providing a parent oil, wherein the parent oil
comprises free fatty acid, wherein the concentration of the free
fatty acid is at least 0.5% wt/wt; providing lowered numbered
alcohol; providing dilute caustic; and, adding the lower numbered
alcohol and the dilute caustic to the parent oil to form a parent
oil mixture.
68. The process of claim 67 wherein the lower numbered alcohol is
selected from a group comprising: methanol, ethanol, propanol,
isopropanol, butanol, isobutanol, propylene glycol, ethylene
glycol, and butylene glycol.
69. The process of claim 67 wherein the parent oil is selected from
a group comprising distiller's corn oil, castor oil, soybean oil,
jatropha oil, algae oil, yellow grease, brown grease, lard, and
beef tallow.
70. The process of claim 69 further comprising heating the
feedstock to form a heated feedstock from 90 degrees Fahrenheit to
150 degrees Fahrenheit; continuously stirring the parent oil
mixture for a period from 10 minutes to 2 hours; and, allowing the
parent oil mixture to settle to form a neat liquid with two phases,
wherein: the first phase comprises feedstock and free fatty acid,
wherein the free fatty acid is at a concentration not more than
0.4% wt/wt; the second phase comprises alcoholic aqueous soap; and
the lower numbered alcohol and the dilute caustic are added to the
heated feedstock to form the parent oil mixture.
71. The process of claim 70 wherein the lower numbered alcohol and
the dilute caustic are added simultaneously.
72. The process of claim 70 wherein the lower numbered alcohol and
the dilute caustic are added sequentially.
73. The process of claim 72 wherein the lower numbered alcohol is
added before adding the dilute caustic.
74. The process of claim 70 wherein the stifling is a low-shear
mixing.
75. The process of claim 70 wherein: the feedstock is heated to a
temperature from 120 degrees Fahrenheit to 150 degrees Fahrenheit;
the stifling period is from 10 minutes to 1 hour; the amount of
dilute caustic provided is from stoichiometric to the amount of
free fatty acid in the feedstock to 20% excess of the
stoichiometric amount; the concentration of the dilute caustic
provided is from 2% to 15% wt/wt; the amount of lower numbered
alcohol provided is from 1% to 20% wt/wt.
76. The process of claim 70 wherein the dilute caustic is selected
from a group comprising: NaOH and KOH.
77. The process of claim 70 wherein: the feedstock is heated to a
temperature from 140 degrees Fahrenheit to 150 degrees Fahrenheit;
the stifling period is from 10 minutes to 30 minutes; the amount of
dilute caustic provided is from stoichiometric to the amount of
free fatty acid in the feedstock to 10% excess of the
stoichiometric amount; the concentration of the dilute caustic
provided is from 3% to 6% wt/wt; the amount of lower numbered
alcohol provided is from 2% to 5% wt/wt.
78. The process of claim 77 wherein: the amount of dilute caustic
provided is from stoichiometric to the amount of free fatty acid in
the feedstock to 5% excess of the stoichiometric amount; the
concentration of the dilute caustic provided is from 4% to 5%
wt/wt; the amount of lower numbered alcohol provided is from 2.5%
to 3.5% wt/wt.
79. The process of claim 70 wherein the parent oil mixture is
allowed to settle at room temperature.
80. The process of claim 70 wherein the parent oil mixture is
allowed to settle at temperature.
81. The process of claim 70 wherein the parent oil mixture is
allowed to settle for a period of 60 minutes to 4 hours.
82. The process of claim 70 wherein the parent oil mixture
separates into a first upper phase and a second lower phase.
83. The process of claim 82 wherein the first upper phase
comprises: parent oil from 91.5% to 99.2% wt/wt; free fatty acid
from 0.15% to 0.45% wt/wt; soap from 0.05% to 0.2% wt/wt; and,
lower numbered alcohol from 0.15% to 0.30% wt/wt.
84. The process of claim 82 wherein the second lower phase
comprises: soap from 8% to 20% wt/wt; water from 50% to 80% wt/wt;
and, parent oil from 2% to 5% wt/wt.
85. The process of claim 82 further comprising extracting the first
upper phase by decanting.
86. The process of claim 70 further comprising providing more than
1 parent oil.
Description
RELATED APPLICATIONS
[0001] The present U.S. non-provisional patent application is
related to and claims priority benefit to an earlier-filed
provisional patent application titled FATTY ACID REDUCTION OF
FEEDSTOCK AND NEUTRAL AND ACIDIC ALKYL ESTER, Ser. No. 62/006,017,
filed May 30, 2014. The identified earlier-filed application is
hereby incorporated by reference into the present application as
though fully set forth herein.
FIELD OF THE INVENTION
[0002] This disclosure relates to processes for refining biodiesel
and to compositions in the refining process. In particular, the
disclosure relates to processes and compositions for reducing free
fatty acid content in the feedstock, and for reducing free fatty
acid content in neutral or acidic alkyl ester mixtures by
neutralizing and separating free fatty acid from neutral or acidic
alkyl esters. The disclosure also relates to processes and
compositions for recovery of glycerin, free fatty acids, and
alcohol reagent for reuse. The disclosure further relates to
processes and compositions related to a reduced amount of alcohol
reagent used in refining.
BACKGROUND
[0003] Biodiesel is a renewable biofuel that can be used in
existing applications, often in blends with petroleum-based diesel.
Production of biodiesel generally occurs via a transesterification
process, using feedstock such as oils or fats. The
transesterification reaction involves mixed fatty glycerides,
predominantly triglycerides, from the feedstock with alkyl
alcohols, often using a catalyst, to produce long chain alkyl
esters--the crude biodiesel. The crude biodiesel is further refined
to remove impurities to obtain a finished biodiesel product.
Biodiesel production and refinement processes are normally costly
and often involve hazardous materials.
[0004] Feedstock normally comprises mixed fatty glycerides and free
fatty acid (FFA). FFA is an impurity that must be sufficiently
reduced in order to obtain the finished biodiesel product, often
with FFA less than 0.25% wt/wt. Unless otherwise indicated, percent
values in this disclosure are calculated on a wt/wt basis. The
quality of feedstock varies from higher quality food-grade oils
having lower FFA levels to lower quality recycled cooking oil and
animal fats having higher FFA levels. Although feedstock with lower
FFA content is preferred for biodiesel production, it is usually
costlier than feedstock with higher FFA content such as animal fats
and recycled cooking oil.
[0005] Feedstock may be subjected to an esterification process in
order to reduce the FFA content. The esterification may be
acid-catalyzed and converts the FFA to long chain alkyl esters. The
esterification may take place either prior to or simultaneously
with the primary transesterification process that produces crude
biodiesel. Although esterification may convert some FFA to crude
biodiesel, the FFA level of the resultant crude usually remains
higher than desired. Further refining is almost always necessary,
and current refining methods to reduce the FFA content of crude
biodiesel produced from feedstock to acceptable levels have various
drawbacks. Current methods are difficult, require significant
amount of capital equipment, require a large excess of reagents
such as methanol, incur long refining time, fail to maximize
recovery of reagents, require expensive resins, generate large
amounts of waste water, and/or decrease yield of finished
biodiesel. It is desirable to reduce the FFA content of feedstock
in a cost-effective manner, including recovering byproducts and
reagents, and not requiring a large excess of reagents. It is also
desirable to refine crude biodiesel produced in a cost-effective
manner, including reducing the FFA level, recovering byproducts and
reagents, not requiring a large excess of reagents, and not
generating a large amount of waste water. Moreover, it is desirable
to produce biodiesel from less expensive feedstock.
[0006] The primary crude biodiesel production reaction is the
transesterification of the mixed fatty glycerides with alkyl
alcohols, and normally results in a mixture that comprises alkyl
esters (the crude biodiesel), alcohols, glycerin, and glycerides
(predominantly monoglycerides). A substantial amount of glycerin in
the production of crude biodiesel is normally removed by gravity
separation and may be further processed and sold. After the bulk of
glycerin is removed from the crude biodiesel, a residual amount of
glycerin nevertheless remains in the crude biodiesel. The
conventional practice is to allow the residual glycerin to remain
in the crude biodiesel at this stage in refining. This is necessary
because many conventional methods to reduce the FFA content of the
crude biodiesel are practical only when the FFA and the biodiesel
are not emulsified. The residual glycerin serves to keep the two
components demulsified. The glycerin later partitions to the soap
phase and is removed by centrifugation. However, soaps often prove
difficult to separate from the alkyl ester, and thus carry large
amount of excess alkyl ester with it. It is desirable to recover a
maximum amount of glycerin, while effectively demulsifying the
crude biodiesel for further refining and improving the yield of
finished biodiesel.
SUMMARY
[0007] Unless otherwise specified, the meanings of the following
terms used throughout this disclosure are provided in this
paragraph. The term "lower alkyl alcohol" refers to alcohols having
1 to 4 carbon atoms and the term "lower alkyl diol" refers to diols
having 2 to 4 carbon atoms. The term "lower numbered alcohol"
refers to a lower alkyl alcohol or lower alkyl diol. Examples of
lower numbered alcohols include methanol and propylene glycol. The
term "alkyl ester(s)" refers to "mono-alkyl ester(s) of lower
numbered alcohols". The term "caustic" refers to an alkali metal
hydroxide. In some embodiments, the caustic is sodium hydroxide or
potassium hydroxide. The terms "glycerin", "glycerine", and
"glycerol" are synonymous. The terms "alcoholic aqueous soap" and
"methylated liquid soap" are synonymous, and both refer to an
aqueous phase comprising the lower numbered alcohol or diol, and
the soap of fatty acid.
[0008] Standard processes such as acid refining and degumming 164
can be used at the outset of biodiesel production to remove
impurities and gums, if necessary, from purchased crude oils and
fats--the crude feedstock. Whether such pre-processing is necessary
depends on the source and quality of purchased crude. The refining
and degumming are known methods for pre-processing the crude
feedstock to form prepared feedstock that is substantially free of
impurities and gums. The prepared feedstock so obtained from
pre-processing includes oils and fats, and are also referred to
herein as parent oils or feedstock. Some processes disclosed herein
are used to reduce the FFA levels of such feedstock.
[0009] Some aspects of the disclosed processes and compositions are
directed to separating FFA from parent oils/feedstock for
production of biodiesel. Some embodiments of this disclosure are
directed to reducing the FFA content of feedstock by neutralizing
and reducing the FFA level. In one embodiment, a process for
reducing the FFA level in feedstock comprises heating the feedstock
to a temperature from 140 degrees Fahrenheit to 150 degrees
Fahrenheit to form a heated feedstock; adding the lower numbered
alcohol and the dilute caustic to the heated feedstock to form a
parent oil mixture; continuously stifling the parent oil mixture
for a period from 10 minutes to 20 minutes; and allowing the parent
oil mixture to settle at temperature to form a neat liquid with two
phases; wherein the feedstock has FFA levels of at least 0.5%
wt/wt. In some embodiments, the parent oil mixture is permitted to
cool off to room temperature while settling. The neat liquid, two
phase separation is an unexpected result, because conventional
knowledge predicts this mixture to be a gel, paste or
semi-solid.
[0010] The types of the feedstock include natural fats and oils,
such as but not limited to, distiller's corn oil, castor oil,
soybean oil, jatropha oil, algae oil, yellow grease, brown grease,
lard, and beef tallow. Embodiments of the lower numbered alcohol
include methanol, ethanol, propanol, isopropanol, butanol,
isobutanol, propylene glycol, ethylene glycol, and butylene glycol.
Embodiments of dilute caustic include aqueous sodium hydroxide and
aqueous potassium hydroxide, and may have concentrations from 2% to
15% wt/wt, from 3% to 6% wt/wt, and from 4% to 5% wt/wt. The amount
of dilute caustic added may be from stoichiometric to the amount of
FFA in the parent oil mixture to 20% excess of stoichiometric.
Dilute caustic may be added in other amounts, including from
stoichiometric to the amount of FFA in the parent oil mixture to
10% excess of stoichiometric, and from stoichiometric to the amount
of FFA in the parent oil mixture to 5% excess of
stoichiometric.
[0011] The lower numbered alcohol and the dilute caustic may be
added simultaneously, or sequentially. When added sequentially, the
preferred sequence is to add the lower numbered alcohol first. In
some embodiments, the feedstock may be heated to a temperature from
120 degrees Fahrenheit to 150 degrees Fahrenheit, or from 90
degrees Fahrenheit to 150 degrees Fahrenheit. In some embodiments,
the parent oil mixture may be continuously stirred for a period
from 10 minutes to 1 hour, or from 10 minutes to 2 hours. In some
embodiments the first phase of the two phases comprises feedstock
and FFA, wherein the feedstock is at least 97% wt/wt, the FFA is at
a concentration not more than 0.4% wt/wt, and the second phase
comprises alcoholic aqueous soap.
[0012] Other aspects of the disclosed processes and compositions
are directed to reducing the FFA in alkyl esters in crude
biodiesel. In one embodiment, crude biodiesel may be obtained by
reacting mixed fatty glycerides of oils or fats with a catalyst,
such as acid, enzyme, or heterogeneous solid catalysts. The
reaction may be a result of transesterification of mixed fatty
glycerides with an alkyl alcohol, such as methanol, ethanol,
propanol, isopropanol, butanol, or isobutanol. The bulk of glycerin
may be removed from the crude biodiesel by gravity separation. The
crude biodiesel mixture so obtained may comprise neutral or acidic
alkyl ester and FFA. In one embodiment, the crude biodiesel mixture
comprises FFA, alkyl ester, and mixed fatty glycerides, wherein the
amount of mixed fatty glycerides is at a concentration not more
than 5% wt/wt. In another embodiment of the crude biodiesel mixture
comprises FFA and alkyl ester, wherein the amount of FFA is no more
than 5% wt/wt, and the amount of alkyl esters is from 75% to 95%
wt/wt. In some embodiments, the crude biodiesel mixture may further
comprise residual glycerin.
[0013] Some disclosed processes are directed to reducing the FFA
content of a crude biodiesel mixture by neutralizing and separating
the FFA from the alkyl ester. In one embodiment, a crude biodiesel
mixture comprising FFA, alkyl ester, and mixed fatty glycerides,
wherein the mixed fatty glycerides are at a concentration not more
than 5% wt/wt, is heated to a temperature from 90 degrees
Fahrenheit to 150 degrees Fahrenheit. Other suitable temperatures
to heat the crude biodiesel mixture include from 120 degrees
Fahrenheit to 150 degrees Fahrenheit, and from 140 degrees
Fahrenheit to 150 degrees Fahrenheit. In some embodiments, residual
glycerin in the crude biodiesel mixture is separated before heating
the mixture by centrifugation, allowing for a further recovery of
glycerin. A lower numbered alcohol and a dilute caustic are added
to the heated mixture to form a second mixture. In some
embodiments, the alcohol and caustic may be added simultaneously,
while in others, one may be added before the other, with a
preference for adding the alcohol first. Embodiments of the lower
numbered alcohol include methanol, ethanol, propanol, isopropanol,
butanol, isobutanol, propylene glycol, ethylene glycol, and
butylene glycol. Embodiments of dilute caustic include aqueous
sodium hydroxide and aqueous potassium hydroxide, and may have
concentrations from 2% to 15% wt/wt, from 3% to 6% wt/wt, and from
4% to 5% wt/wt. The amount of dilute caustic added may be from
stoichiometric to the amount of FFA in the crude biodiesel mixture
to 20% excess of stoichiometric. Dilute caustic may be added in
other amounts, including from stoichiometric to the amount of FFA
in the crude biodiesel mixture to 10% excess of stoichiometric, and
from stoichiometric to the amount of FFA in the parent oil mixture
to 5% excess of stoichiometric.
[0014] The second mixture is low-shear mixed for a period from 10
minutes to 2 hours. The mixing period may also be from 10 minutes
to 1 hour, or 10 minutes to 20 minutes. The heat temperature of the
second mixture is maintained during the mixing period. In one
embodiment, the mixing is stifling moderately at 200 rpm with a
magnetic stir bar. After the mixing, in one embodiment, the second
mixture is centrifuged. In another embodiment, the second mixture
is allowed to settle for 1 to 3 hours while maintaining the heat
temperature. After settling, it was surprising to discover that the
second mixture demulsifies into neat liquid an upper phase and a
lower phase. In one embodiment, the upper phase comprises alkyl
ester, and the lower phase comprises alcoholic aqueous soap. The
two phases are separated by decantation.
[0015] In another aspect, disclosed processes are directed to
recovering FFA from the refining process above. Thus, in one
embodiment, the lower phase that comprises alcoholic aqueous soap
is reacted with acid, such as hydrochloric acid, acetic acid,
citric acid, phosphoric acid, sulfuric acid, and methanesulfonic
acid. The reaction of the soap with the acid produces FFA, which is
recovered and recycled. In a further aspect of this disclosure,
processes are directed to recovering the lower numbered alcohol
used above. Thus, in one embodiment, the methanol is removed from
upper phase of the second mixture, resulting in a stripped alkyl
ester mixture.
[0016] Other embodiments are directed to further refining the
stripped alkyl ester mixture. An embodiment is directed to washing
the stripped alkyl ester mixture with soft water, resulting in a
mixture having two components, a wet ester component and a soap
water component. The disclosed processes are further directed to
removing the soap water component from the mixture, and drying the
west ester component.
BRIEF DESCRIPTION OF DRAWINGS
[0017] FIG. 1a is a diagram of some aspects related to reducing
free fatty acid in feedstock.
[0018] FIG. 1b is a diagram of aspects related to reducing free
fatty acid in feedstock.
[0019] FIG. 1c is a diagram of some aspects related to reducing
free fatty acid in neutral or acidic alkyl ester, and recovering
reagents.
[0020] FIG. 1d is a diagram of aspects related to reducing free
fatty acid in neutral or acidic alkyl ester, and recovering
reagents.
[0021] FIG. 1e is a diagram of aspects related to recovering
reagents in reducing free fatty acid in alkyl ester.
DETAILED DESCRIPTION
[0022] Systems, processes, and compositions are disclosed that
enable reduction of free fatty acid (FFA) content in the feedstock
that can be used in the production of crude biodiesel. Also
disclosed are systems, processes, and compositions in the refining
of crude biodiesel that enable reduction of FFA content, increasing
the recovery of glycerin, FFA and alcohol, decreasing the amount of
waste water, and an efficient, effective, and less costly refining
of crude biodiesel. The disclosure is broadly directed to the use
of a lower numbered alcohol and a dilute caustic in a refining
process to reduce the FFA content of the feedstock for producing
crude biodiesel and to reduce the FFA of the crude biodiesel
produced, while maximizing the recovery of glycerin, alcohol, and
FFA, and minimizing waste water generated. The result of some
embodiments of the disclosed process, contrary to what conventional
knowledge predicts, was an unexpected neat liquid having two-phase
demulsified mixture.
[0023] A fuel with a high level of FFA causes problems in engines.
Feedstock used for producing crude biodiesel normally comprises
FFA, oftentimes a high level of FFA. The types of feedstock that
may be used with some embodiments in this disclosure include
natural fats and oils, such as but not limited, to distiller's corn
oil, castor oil, soybean oil, jatropha oil, algae oil, yellow
grease, brown grease, lard, and beef tallow. The list of feedstock
types is illustrative and not intended to be limiting. The FFA
content is usually reduced during refining of crude biodiesel in
order for the biodiesel to meet the total acid number (TAN) fuel
quality standards set by ASTM International (ASTM). The TAN of a
biodiesel fuel is an indicator of FFA content.
[0024] Some embodiments of this disclosure are directed to reducing
the FFA content of feedstock by neutralizing and separating the
FFA, accomplished by mixing the feedstock with lower numbered
alcohol and dilute caustic. After the FFA is separated from the
feedstock, the resulting refined feedstock in some embodiments
comprises less than 0.5% wt/wt FFA. Unless otherwise indicated,
percent values in this disclosure are calculated on a wt/wt basis.
Such refined feedstock is ideal for producing crude biodiesel via
transesterification, which usually involves methanol or ethanol,
and may be catalyzed by base (e.g., methanolysis), acid, enzymes,
or heterogeneous solid catalysts.
[0025] Standard processes such as acid refining and degumming 164
can be used at the outset to remove impurities and gums, if
necessary, from purchased crude oils and fats--the crude feedstock.
Whether such pre-processing is necessary depends on the source and
quality of purchased crude. The refining and degumming are known
methods for pre-processing the crude feedstock to form prepared
feedstock ready for further processing. The prepared feedstock so
obtained from pre-processing includes oils and fats, and are also
referred to herein as parent oils or feedstock. Some processes
disclosed herein are used to reduce the FFA levels of such
feedstock.
[0026] In some embodiments, the feedstock 154 may comprise at least
0.5% wt/wt FFA. First, the feedstock 154 is heated to a temperature
from 90 degrees F. to 150 degrees F. The feedstock 154 may be
heated to other suitable temperatures, including from 120 degrees
F. to 150 degrees F., and from 140 degrees F. to 150 degrees F.
Dilute caustic 158 is provided in an amount stoichiometric to the
FFA content of the feedstock 154. Dilute caustic 158 may also be
provided in other amounts, including 20% excess of the
stoichiometric amount, 10% excess of the stoichiometric amount, and
5% excess of the stoichiometric amount. In one embodiment, a lower
numbered alcohol 156 is provided in an amount of 1% to 20% wt/wt.
In other embodiments, the lower numbered alcohol 156 is provided in
amounts from 2% to 5% wt/wt, and from 2.5% to 3.5% wt/wt.
Embodiments of lower numbered alcohol 156 include methanol,
ethanol, propanol, isopropanol, butanol, isobutanol, propylene
glycol, ethylene glycol, and butylene glycol. Embodiments of the
provided dilute caustic 158 include aqueous sodium hydroxide and
aqueous potassium hydroxide, and may have concentrations from 2% to
15% wt/wt, from 3% to 6% wt/wt, and from 4% to 5% wt/wt.
[0027] In an embodiment, the provided lower numbered alcohol 156
and the provided dilute caustic 158 are added to the heated
feedstock, resulting in a feedstock mixture, sometimes also
referred to as a parent oil mixture 152. In some embodiments, the
lower numbered alcohol 156 and the dilute caustic 158 are added
simultaneously to the heated feedstock. In other embodiments, the
lower numbered alcohol 156 and the dilute caustic 158 are added one
after the other, with a preference for adding the lower numbered
alcohol 156 first. The parent oil mixture 152 is stirred
continuously at temperature for a period from 10 minutes to 90
minutes. After stifling, the parent oil mixture 152 is allowed to
settle at temperature for a period from 60 minutes to 180 minutes.
In other embodiments where the temperature is not maintained while
the parent oil mixture 152 is allowed to settle, the settling
period may be from 90 minutes to 4 hours. The result at the end of
the settling period is two neat liquid phases. The upper phase 162
may comprise from 91.5% to 99.2% wt/wt parent oil, from 0.15% to
0.45% wt/wt FFA, from 0.05% to 0.2% wt/wt soap, and from 0.15% to
0.30% wt/wt alcohol. The lower phase 166 may comprise from 8% to
20% wt/wt soap content, from 50% to 80% wt/wt water, and from 2% to
5% wt/wt parent oil. The upper phase, now a low FFA feedstock
phase, may be used to feed standard processes for producing crude
biodiesel, such as acid-, base-, enzyme-, heterogeneous
solid-catalyzed transesterification, and enzyme- or acid-catalyzed
combined esterification/transesterification 102.
[0028] In one example, dried distiller's corn oil (DCO, less than
0.25% moisture) is the parent oil (feedstock). The DCO was obtained
from an ethanol production facility. Analysis of this parent oil
shows that it comprises 8.2% wt/wt FFA and no detectable level of
soap. A 100 g sample of the parent oil was heated to 122.degree. F.
Then, 12.3 g of 95% wt/wt methanol (5% wt/wt water) was added to
the parent oil followed by 30.5 g of 4% wt/wt dilute aqueous
caustic. The mixture was stirred continuously at temperature for 20
minutes, and then allowed to settle at room temperature for two
hours. Within two hours, two neat liquid phases resulted: an upper
phase--the low FFA parent oil phase--comprising de-acidified corn
oil and a lower phase comprising alcoholic aqueous soap. Analysis
of the upper phase corn oil layer showed that it comprised 0.25%
wt/wt FFA, 0.12% wt/wt soap and 0.22% wt/wt methanol, the
remainder, >99% wt/wt, being the DCO parent oil. Thus, this
example discloses reducing the 8.2% wt/wt FFA of a parent oil to
0.25% wt/wt under modest conditions, using inexpensive reagents and
basic equipment, and in a short amount of time. The resulting upper
phase low FFA corn oil layer can now be further processed, for
example, as a low FFA feedstock to a standard transesterification
process for producing crude biodiesel.
[0029] Other embodiments of this disclosure are directed to
reducing the FFA content of the crude biodiesel. The FFA content is
usually reduced during refining of the crude biodiesel in order to
obtain a finished biodiesel that meets ASTM standards. The crude
biodiesel 148 may be obtained via known methods, such as enzyme-,
acid-, or heterogeneous solid-catalyzed transesterification of
feedstock with a lower numbered alcohol such as methanol. The crude
biodiesel 148 may be obtained by other known methods such as the
enzyme- or acid-catalyzed combined
esterification/transesterification reactions 102 with, for example,
methanol. FIG. 1. The resulting crude 148 is typically allowed to
settle and separated by gravity into crude ester 104 and crude
glycerin 106. The crude glycerin is usually collected 108 for
further processing to be sold. The crude ester 104 comprises the
desired long chain alkyl ester, FFA, glycerin, alkyl alcohol, and
mixed fatty glycerides, primarily monoglycerides. In one aspect of
the disclosure, the amounts of the crude ester 104 components at
this stage in refining are FFA at 4% wt/wt or lower; mixed fatty
glycerides, primarily monoglycerides at 5% wt/wt or lower; and
glycerin at 0.5% wt/wt or lower.
[0030] One aspect of the disclosure relates to removing and
recovering glycerin--a major byproduct of producing crude
biodiesel. According to current practice, after transesterification
produces crude biodiesel, a glycerin-rich component 106 is removed
after gravity separation 108. After removing crude glycerin 106,
the crude ester component 104 normally retains residual glycerin.
In some embodiments, the residual glycerin in the crude ester 104
is less than 1%. Although the residual glycerin can be
substantially removed from the crude ester 104, for example by
centrifugation, the conventional practice is to continue refining
with some glycerin in the crude ester. Thus, some embodiments of
this disclosure depart from the conventional practice by
substantially removing the residual crude glycerin 112 by
centrifugal separation 110, to be collected and further processed
108. The amount of glycerin recovered is thereby increased and
preserved from subsequent salt or soap contamination. After the
residual glycerin 112 is removed by centrifugal separation 110, the
amount of glycerin remaining in the resulting ester 118 is
significantly reduced. In some embodiments, the amount of glycerin
remaining after centrifugation 110 is from 0.05% to 0.15% wt/wt. In
other embodiments, the refining continues with the residual
glycerin in the crude ester. That is, the residual glycerin 112 is
not removed from the crude ester 104 during the process.
[0031] Embodiments directed to reducing the FFA content in refining
biodiesel further include refining the ester 118 component. In some
embodiments, the ester 118 comprises glycerin from 0.05% to 0.15%
wt/wt, FFA from 1.75% to 4.00% wt/wt, glycerin from 0.05% to 0.15%
wt/wt, and at least 93% wt/wt alkyl ester. The ester 118 further
comprises glycerides, predominantly monoglycerides from 1.75% to
2.75% wt/wt, soap from 75 ppm to 100 ppm, and lower numbered
alcohol from 1.2% to 2.2% wt/wt. In one embodiment, the ester 118
is heated to approximately 150 degrees Fahrenheit. The ester 118
may be heated in other embodiments to temperatures from 90 degrees
Fahrenheit to 150 degrees Fahrenheit, from 120 degrees Fahrenheit
to 150 degrees Fahrenheit, and from 140 degrees Fahrenheit to 150
degrees Fahrenheit. To the heated ester 118, a lower numbered
alcohol 114 and dilute caustic 116 are added, resulting in a
mixture 128. Dilute caustic 116 is provided in an amount
stoichiometric to the FFA content of the ester 118. Dilute caustic
116 may also be provided in other amounts, including 20% excess of
the stoichiometric amount, 10% excess of the stoichiometric amount,
and 5% excess of the stoichiometric amount. In some embodiments the
lower numbered alcohol 114 and the dilute caustic 116 are added
simultaneously. In other embodiments, either the lower numbered
alcohol 114 or the dilute caustic 116 is added first, with a
preference for adding the lower numbered alcohol 114 first. In one
embodiment, the lower numbered alcohol 114 is added in an amount of
1% to 20% wt/wt. In other embodiments, the lower numbered alcohol
114 is added in amounts from 2% to 5% wt/wt, and from 2.5% to 3.5%
wt/wt. Embodiments of lower numbered alcohol 114 include methanol,
ethanol, propanol, isopropanol, butanol, isobutanol, propylene
glycol, ethylene glycol, and butylene glycol. Embodiments of the
dilute caustic 116 include aqueous sodium hydroxide and aqueous
potassium hydroxide. Embodiments of the dilute caustic 116 may have
concentrations from 2% to 15% wt/wt, from 3% to 6% wt/wt, and from
4% to 5% wt/wt.
[0032] After the lower numbered alcohol 114 and dilute caustic 116
are added, the mixture 128 is subjected to low-shear mixing at
temperature, from 10 minutes to 90 minutes. The result was an
unexpected two-phase demulsified mixture 120. Because conventional
knowledge predicts this mixture 120 to be a gel, paste, or
semi-solid, it is completely unexpected that the mixture is a neat
liquid. Further, in the embodiments where the glycerin is further
reduced to an amount from 0.05% to 0.15% wt/wt by centrifugation,
current knowledge predicts that such a mixture 120 of the ester and
FFA will be emulsified given such low glycerin content.
[0033] In an embodiment, the demulsified mixture 120 is allowed to
settle at temperature for a period from 60 minutes to 180 minutes.
In some embodiments, the demulsified mixture 120 is centrifuged.
After either settling or centrifugation, a first phase upper
component 122 is extracted, e.g., by decanting, and a second phase
lower component 124 is removed by gravity, for example by draining.
The first phase comprises ester having low total acid number (the
"low TAN ester") 122 and the second phase is a byproduct alcoholic
aqueous soap phase 124, comprising the soap of the fatty acid and
the lower numbered alcohol 114. In an embodiment, the upper
component low TAN ester phase 122 comprises soap from about 200 ppm
to about 600 ppm; FFA at a concentration not more than 0.25% wt/wt;
mixed fatty glycerides, primarily monoglycerides from about 0.60%
to about 1.00% wt/wt; alcohol from about 1.3% to about 1.7% wt/wt;
at least 97% wt/wt alkyl ester; and, no detectable glycerin. Thus,
the disclosed process is an easy, short, and inexpensive process to
very effectively reduce FFA. Moreover, the amount of ester in the
lower component alcoholic aqueous soap phase 124 is less than 2%
wt/wt of the desired ester in some embodiments. Thus, the mixture
128 of ester 118, lower numbered alcohol 114, and dilute caustic
116 quickly and easily demulsifies into a two phase mixture 120, a
phase that comprises a low TAN ester 122 and the another phase that
comprises alcoholic aqueous soap 124. The low TAN ester 122 phase
has very low soap content, and the alcoholic aqueous soap phase 124
has very little ester content.
[0034] In the embodiments wherein the residual glycerin 112 is not
removed from the crude ester 104 during the process, the residual
glycerin 112 becomes irreversibly contaminated with soap and/or
salt later in the process. Thus, it is desirable to remove the
residual glycerin 112 from the crude ester 104, for example by
centrifugal separation 110, before subsequent processing.
[0035] In one embodiment of the process, residual lower numbered
alcohol in the low TAN ester 122 is removed 130 by a flash vessel
under the following conditions: 100 mm Hg absolute pressure and 260
degrees F. In an embodiment, the result is demethylated
("stripped") ester 132--that is, ester with methanol removed. The
stripped ester 132 in another embodiment is treated with soft water
134 to wash residual soap, resulting in a mixture of soap water 136
and wet ester 138. The soap water 136 is separated from the wet
ester 138. The wet ester 138 is dried using known methods to remove
water resulting in the finished biodiesel 140. Acid 142 is added to
the soap water 136 to recover the free fatty acids 126, which are
returned for further processing 144. Embodiments of suitable acids
include sulfuric acid 142, hydrochloric acid, acetic acid, citric
acid, phosphoric acid, sulfuric acid, and methanesulfonic acid.
Similarly, acid is also added to the alcoholic aqueous soap 124
according to some embodiments, resulting in free fatty acids 126,
which are recycled 144, and waste water 146. The waste water 146 is
discarded.
[0036] In one example, 2000 g ester 118 was obtained after
centrifugation 110 of the crude ester 104 for 9 minutes at 2000
rpm. The ester 118 composition comprised FFA at 2.25% wt/wt,
monoglycerides at 2.20% wt/wt, diglycerides at 0.11% wt/wt, free
glycerin at 0.091% wt/wt, methanol at 1.656% wt/wt, moisture at
0.0375% (375 ppm), and alkyl ester in remaining balance. The ester
118 was heated to 150 degrees F. 60.0 g of 95% wt/wt methanol (5%
wt/wt water) and 4% wt/wt sodium hydroxide were added sequentially
while stifling. Temperature was maintained at 150 degrees F. and
the mixture was stirred moderately (200 rpm with a magnetic stir
bar) and continuously for 35 minutes. The mixture was then allowed
to settle for two hours while maintained at 150 degrees F. Within
two hours, two neat liquid phases with clear separation had
resulted. A lower aqueous soap phase had a total mass of 314.1 g,
comprised soap content at 16.9% wt/wt and moisture at 54% wt/wt,
and had a saponification value of 13.9 mg KOH/g sample, which is
about 7% esters, primarily monoglycerides and the balance methyl
esters. An upper ester phase had a total mass of about 1685.8, and
comprised FFA at 0.2% wt/wt, soap at 0.0250% wt/wt (250 ppm),
moisture at 2000 ppm, monoglycerides at 0.78% wt/wt, diglycerides
at 0.02% wt/wt, methanol at 1.52% wt/wt, and no detectable levels
of glycerin. Thus, this example discloses reducing the FFA of a
crude ester to 0.2% wt/wt under modest conditions, using
inexpensive reagents and basic equipment, and in a short amount of
time. The resulting upper ester phase--the low TAN ester
122--reduces the FFA content to a level that meets ASTM
specifications. The low TAN ester can now be further refined, for
example, to remove methanol 130, to wash with soft water 134 to
separate the soap water 136, and to dry to produce the finished
biodiesel 140.
[0037] In a second example, another 2000 g batch of ester 118 was
obtained after centrifugation 110 of the crude ester 104 for 9
minutes at 2000 rpm. The ester 118 composition comprised FFA at
1.9% wt/wt, monoglycerides at 1.449% wt/wt, methanol at 0.635%
wt/wt. 100 g of the ester was heated to 120 degrees F. 4.0 g of 95%
wt/wt methanol (balance water) was added, followed by 10.4 g of 4%
wt/wt aqueous potassium hydroxide. The mixture was allowed to stir
moderately (200 rpm with a magnetic stir bar) and continuously for
20 minutes. The mixture was then allowed to separate for four hours
at room temperature. Within those four hours, two neat liquid
phases formed. The resulting upper ester phase--the low TAN ester
122--comprised FFA at 0.2% wt/wt, soap at 550 ppm, monoglycerides
at 0.71% wt/wt, and methanol at 0.81% wt/wt. This example discloses
reducing FFA of a crude ester to a level that meets ASTM
specifications.
[0038] In a third example, 100 g of a crude ester 104 was
centrifuged for 9 minutes at 2000 rpm. The resulting ester 118
comprised FFA at 1.9% wt/wt, monoglycerides at 1.449% wt/wt,
methanol at 0.635% wt/wt, and was heated to 120 degrees F. 5.0 g of
70% propylene glycol (balance water) was added, followed by 7.45 g
of 4% wt/wt aqueous sodium hydroxide. The mixture was allowed to
stir moderately (200 rpm with a magnetic stir bar) and continuously
for 20 minutes. The mixture was then allowed to separate for four
hours at room temperature. Within those four hours, two neat liquid
phases formed. The resulting upper ester phase--the low TAN ester
122--comprised FFA at 0.15% wt/wt, soap at 500 ppm, monoglycerides
at 0.49% wt/wt, and methanol at 0.04% wt/wt. This example discloses
reducing FFA of a crude ester to a level that meets ASTM
specifications.
[0039] When introducing elements of aspects of the invention or the
embodiments thereof, the articles "a," "an," "the," and "said" are
intended to mean that there are one or more of the elements. The
terms "comprising," "including," and "having" are intended to be
inclusive and mean that there may be additional elements other than
the listed elements.
[0040] As various changes could be made in the above processes and
products without departing from the scope of aspects of this
disclosure, it is intended that all matter contained in the above
description and shown in the accompanying drawings shall be
interpreted as illustrative and not in a limiting sense.
* * * * *