ZA200602242B

ZA200602242B - Oil extraction

Info

Publication number: ZA200602242B
Application number: ZA200602242A
Authority: ZA
Inventors: Chou Chih-Chung; Chien Kohsin
Original assignee: Oilseeds Biorefinery Corp
Priority date: 2006-03-17
Filing date: 2006-03-17
Publication date: 2007-05-30

Description

2003/0 0262

Attorney’s Docket No.: 17915-004001 ® Oil Extraction

BACKGROUND

Oil has been routinely recovered from oil-bearing plants for thousands of years. A large variety of plants produce sufficient quamtities of oil that can be processed into edible or industrial products.

Oil from oil-bearing plants is typically~ extracted by solvents. Solvent extraction is a mass-transfer process in which one or mo re materials are transported from a mixture to a solvent phase, resulting in their separatiom from the mixture. Various organic solvents have been used for commercial extra ction. However, there still exists a need in developing a cost-effective solvent and environment-friendly extraction process for recovering oil from oil-bearing plants.

SUMNMIARY

This invention is based on the discove=ry that a triglyceride can be readily extracted from an oil-bearing seed by using a fatty acid alkyl ester as a solvent.

In one aspect, this invention features &a method of producing a triglyceride solution. The method includes contacting a li quid fatty acid alkyl ester and a substance containing triglyceride (e.g., at 15-180°C or 25-150°C) so that the triglyceride is dissolved into the fatty acid alkyl ester to forrm a triglyceride solution. Preferably, the fatty acid alkyl ester is obtained, prior to the contacting step, by reacting alcohol (e.g. a

C1-C8 primary or secondary alcohol) with tri glyceride extracted from the same triglyceride-containing substance. Exemplarsy alcohols include methanol, ethanol, n- propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, neopentanol and n- hexanol. The fatty acid alkyl ester and the tri glyceride-containing substance can be mixed at a weight ratio ranging from 1:2 to 10:1 (e.g., from 1:1 to 6:1).

The triglyceride-containing substance can be oil-bearing seed. The term “oil- bearing seed” refers to any plant seed suitable for oil extraction. Examples of oil-bearing seed include, but are not limited to, soybean, peanut, sunflower seed, rapeseed, corn (e.g., corn germs or distillers dried corn grains), jat ropha seed, karanja seed, neem seed, mahua seed, castor bean, rubber seed, cotton seed, palm kernel, olive, almond kernel, babassu

L

Attzomey’s Docket No.: 17915-004001 [ seed, ben seed, cardoon seed, camelina seed, linseed, hazelnut kxernel, hemp seed, mustard seed (e.g., Ethiopian mustard seed and Indian mustard seed), jojoba seed, poppy seed, safflower seed, sesame seed, wheat grain, sal seed, cramb e seed, cuphea seed, nahor seed, and tobacco seed. Alternatively, the triglyceride-containimng substance can be obtained from parts other than seed in certain oil-bearing plants. The term “oil-bearing plant” refers to any plant that contains oil in any part (e.g., seed or fruit) and is suitable for oil extraction. Examples in addition to those listed above iraclude, but are not limited to, rice bran, palm (e.g., palm fruit pulp), yellowwood, and algae.

The fatty acid alkyl ester described above can contain a C1-C8 primary or secondary alkoxy moiety or a C6-C24 fatty acid moiety. The term “alkoxy” refers to a straight or branched, saturated or unsaturated, non-aromatic hyadrocarbon moiety containing an oxygen radical, such as -OCH; or -OCH=C,H,. “The term “fatty acid” mentioned herein refers to a straight or branched, saturated or vansaturated monobasic organic acid. Exemplary fatty acids include, but are not limited to, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaaric acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid, cis-11-eicosenoic acid, and er-ucic acid. Exemplary fatty acid alkyl esters include, but are not limited to, fatty acid omethyl esters, fatty acid ethyl esters, fatty acid n-propyl esters, fatty acid isopropyl estems, fatty acid n-butyl esters, fatty acid isobutyl esters, fatty acid n-pentyl esters, fatty acid isopentyl esters, fatty acid neopentyl esters, and fatty acid n-hexyl esters. Typically, the fatty acid alkyl ester can have a boiling point of 150-500°C.

The details of one or more embodiments of the invention are set forth in the description below. Other features, objects, and advantages of t_he invention will be apparent from the description and from the claims.

DETAILED DESCRIPTION

This invention relates to extracting a triglyceride from an oil-bearing plant using a fatty acid alkyl ester as a solvent at a certain temperature (e.g., 15-180°C) to obtain an extraction solution. When the oil-bearing plant contains a high oil content, the plant can

~Atorney’s Docket No.: 17915-004001 ® be optionally pressed or squeezed to remove a portion of the «oil before extraction. If desired, the oil-bearing plant can also be pulverized to facilitate extraction.

The extraction process can be performed by methods ‘well known in the art. As an example, it can be carried out by mixing a pulverized oil-beamring plant and a fatty acid alkyl ester in a continuous stirred-tank reactor for a predeterrnined period of time. As anothesr example, it can be carried out continuously by bring together, without mixing, a pulverized oil-bearing plant and a fatty acid alkyl ester in a plug flow reactor or a fixed bed re=actor through a counter-current flow, a co-current flow , or a combination of both flows— The extraction process can be carried out by either a batch method or a flow method. Typically, a flow method can be used to help maintain reasonable manu-facturing costs.

The extraction can be performed at different temperatures. Generally, extraction at a hm gher temperature (e.g., above 35°C) recovers more oil. However, high temperature extraction may also produce more impurities (e.g., phosphorus and moisture). The weighmtratio between the solvent and the oil-bearing plant used in the extraction process depermds on various factors, e.g., the type of the oil-bearing p lant and the oil content in the oil-be=aring plant. For example, one can use a low weight rat io for extracting a prepressed oil-be=aring plant, from which a portion of the oil in the plant has been removed.

Typically, the weight ratio is in the range of 1:2 to 10:1. Othmer extraction conditions (e.g., the extraction time) can be determined empirically.

The fatty acid alkyl ester used in the extraction proce ss can be prepared by known methods. For example, a fatty acid alkyl ester can be prepared by an esterification reacti on between an alcohol (e.g., ethanol) and a fatty acid (e.g., stearic acid). As another exam le, a fatty acid alkyl ester can be prepared by a transeteerification reaction between an alcohol and a triglyceride, such as the transeterification resactions described in U.S.

Paten t Application 10/945,339. Preferably, the fatty acid alkyl ester is prepared from a

C1-C 4 alcohol. Extractions with such a fatty acid alkyl ester generally produce a trigly ceride solution that contains less impurities (e.g., phosphorus and moisture). The trigly ceride used to prepare the fatty acid alkyl ester can be obtained from a plant different from the plant to be extracted. Preferably, the triglyceride is obtained from a plant that is the same as the plant to be extracted. In that cas.e, the triglyceride extracted

Attorney’ss Docket No.: 17915-004001 ® from the plant is identical to the triglyceride used to prepare the extraction solvent (i.e., the fa tty acid alkyl ester). As a result, if the extracted triglyceride is subsequently used to prepa re the fatty acid alkyl ester via a transesterification reaction, the fatty acid alkyl ester An an extraction solution can be used as a solvent for the reacticon and therefore needs not to be separated from the extracted triglyceride.

After the extraction process, the fatty acid alkyl ester can be soptionally separated from the extracted triglyceride by partially or completely removal frcom an extraction soluti on. The removal step can be carried out by distillation using a vacuum column, a short—path vacuum distillation unit, or any other suitable device known in the art.

Whet her to remove the fatty acid alkyl ester partially or completely &rom an extraction solution or to remove it at all depends on various factors, such as the= ratio between the fatty acid alkyl ester and the extracted triglyceride and the end use o-f the extracted trigly ceride.

The extracted triglyceride can be further processed for use in. the food and pharrmaceutical industries. [t can also be used as a raw material for poreparing fatty acid alkyl esters or fatty alcohols. Fatty acid alkyl esters are useful as diesel fuels, lubricant oils, or chemical intermediates. Fatty alcohols are useful as surfacta_nts in detergent industry.

The specific examples below are to be construed as merely iBRlustrative, and not limitaxtive of the remainder of the disclosure in any way whatsoever. Without further elabosration, it is believed that one skilled in the art can, based on thes description herein, utiliz e the present invention to its fullest extent. All of the publicatieons cited herein, including patents, are hereby incorporated by reference in their entirety.

Example

Soybeans were first ground into a powder and sieved through a filter having a size of 40 mesh (about 425-520 um). Soybean powder having an averagze particle size of less than 40 mesh, which is similar to a dehulled powder, was collected zand used for oil extra ction.

The soybean powder obtained above was dried until it had a moisture content of less t han 6 wt%. The powder was then extracted using soybean baseed fatty acid methyl

JNA LH n0a/ 02282 orney'S Docket No.: 17915-004001 ® esters (BIFAMES) as a solvent in a beaker with agitation. The soybean based FAMEs were previously prepared by a transesterification reaction between methanol and triglycerides obtained from soybean.

The extraction process was carried out by using FAMESs at a solvent-to-powder weight ratio of 6:1 at 35°C. The beaker was agitated at a revolution per minute (rpm) of 300. A fter 30 minutes of extraction, the content of the miscella (i.e, the solution contain ing extracted oil) was determined. The oil content in the m ‘iscella was determined by HPL.C (JASCO model 1580; column: Luna Su C18, 2 um, 250*4.6 mm, Phenomenex,

Torrance, CA; mobile phases: methanol, and hexane/isopropyl alcohol (4:5); UV detector: UV-2075, JASCO Inc., Tokyo, Japan). The moisture cormtent in the miscella was determined by the Karl-Fisher method according to the operation manual, MKC-3500

KF Mo isture Titrator Kyoto Electronic Manufacturing Co. Ltd, Ver. 04, #595-0006. The phosph<orus content in the miscella was determined according to A tmerican Oil Chemist’s

Society” official method Ca 12-55. The results showed that miscell a contained a moisture content. of 818 ppm, a phosphorus content of 14.4 ppm, and an oil content of 3.60 wt%.

The we ight of the extracted oil was 20% of that of the soybean powder.

The soybean powder was also successively extracted with FAME: at a reduced solvent -to-powder ratio in a beaker. Specifically, the powder was extracted twice at a solvent -to-powder ratio of 1: 1 by agitating the beaker at a rpm of 1.,000 for 15 mintues.

After the first extraction, the miscella contained a moisture content of 989 ppm, a phosph orus content of 23.4 ppm, and an oil content of 14.08 wt%. After the second extraction, the miscella contained a moisture content of 1,428.3 pprm, a phosphorus content of 14.23 ppm, and an oil content of 6.13 wt%. After two extractions, the total weight of the extracted oil was 21.59% of that of the soybean powder.

Finally, the soybean powder obtained above was also extra cted via a conventional method. Specifically, the powder was extracted by Gerhardt’s Sox therm automated soxlet system using hexane as a solvent at a solvent-to-powder ratko of 8:1 at 65°C. This method is described in Official and Tentative Methods, the American Oil Chemist

Society”, Vol. 1, AOCS Champaign 11 (1980) Method Am 2-93. The results show that the oil contained a phosphorus content of 265 ppm. The weight of the extracted oil was 18.8% of that of the soybean powder.

Attorney’s Docket No: 179 15-004001 ( Example 2

Two types of oil-bearing seeds were extracted by FAMEs prepared from triglycerides obtained from their corresponding oil sources. Specifically, sunflower seeds were extracted by sunflower seed based FAMEs and peanuts (ground nuts) were extracted by pearut based FAMEs.

Sunflowesr seeds were dehulled and ground into a powder having an averazge particle size of less than 40 mesh. The powder was dried until it had a moisture c=ontent of less than 6 wt<%. It was then extracted twice in a beaker with sunflower seed based

FAME at a solvent-to-powder ratio of 1:1. Each extraction was conducted by agit ating the beaker at a rpm of 1,000 for 15 minutes at 35°C. After the first and second extractions, the rmiscella contained a moisture content of 794 and 831 ppm, respectively, a phosphorus comtent of 49.6 and 47.8 ppm, respectively, and an oil content of 35 .65 and 12.30 wt%, respectively. After two extractions, the total weight of the extracted Oil was 54.83% of that ofthe sunflower seeds.

Peanuts were ground into a powder having an average particle size of less than 25 mesh (i.e., ab out 425-710 um) and then dried until it contained less than 6 wt%o6 of moisture. The powder was then extracted four times in a beaker with peanut base=d

FAMESs at a solv ent-to-powder ratio of 1:1. Each extraction was conducted by agitating the beaker at a rppm of 1,000 for 15 minutes at 35°C. After the first, second, third , and fourth extractiorms, the miscella contained a moisture content of 701, 690, 661, aned 661 ppm, respectivel y, a phosphorus content of 23.5, 16.4, 0, and 0 ppm, respectively , and an oil content of 31 .4, 10.9, 2.63, and 0.78 wt%, respectively. After three extraction._s, the total weight of the extracted oil was 45.83% of that of the peanuts. After four extractions, the total weight of the extracted oil was 47.48% of that of the peanuts. :

Example 3

Soybean s were extracted by soybean based fatty acid ethyl esters (FAEEs ).

Soybean based FFAEEs were prepared by a transesterification reaction between et hanol and triglycerides obtained from soybeans.

Soybean s were first ground into a powder having an average particle size of less than 40 mesh and then dried until it had a moisture content of less than 6 wt%. T he e200 RJ 322462

Attorney's Docket No.: 179 715-004001 ® powder was then extract ed three times in a beaker with soybean based FAEEs at a. solvent-to-powder ratio «of 1:1. Each extraction was conducted by agitating the be aker at a rpm of 1000 for 15 mimutes at 35°C. After the first, second, and third extraction s, the miscella contained a mo isture content of 650, 652, and 694 ppm, respectively, a phosphorus content of 39.4, 23.3, 16.0 ppm, respectively, and an oil content of 14.09, 5.93, and 1.05 wt%, respectively. After three extractions, the total weight of the extracted oil was 20.1% of that of the soybean powder.

Example 4

Soybeans were e=xtracted by a method similar to that described in Examples 3 except that soybean based fatty acid butyl esters (FABEs) were used as a solvent.

Soybean based FABEs were prepared by a transesterification reaction between n-butanol and triglycerides obtained from soybeans.

After the first, sescond, and third extractions, the miscella contained a mois ture content of 576, 519, andk 479 ppm, respectively, a phosphorus content of 27.32,13 .49, and 0.96 ppm, respectively, and an oil content of 15.93, 5.10, and 1.60 wt%, respectiv ely.

After three extractions, gthe total weight of the extracted oil was 21.6% of that of the soybean powder.

Example 5

Soybeans were e=xtracted by a method similar to that described in Example 4 except that the extractio ns were conducted at a reduced agitation rate, i.e., at a rpran of 500. Further, the extrac tions were conducted at four different temperatures, i.e., 35°C, 60°C, 100°C, and 150°C.

The results show that the total weight of the extracted oil increased at highaer temperatures. Specifically, at 35°C, 60°C, 100°C, and 150°C, the total weights of the extracted oil were respe ctively 21.42, 23.25, 28.4, and 32.8% of those of soybean powder. The results als o show that at 35°C, 60°C, 100°C, and 150°C, the phosphorus contents in a mixture cosntaining a combination of miscella obtained after each extraction were 16.2, 18.64, 48.32 and 91.12 ppm, respectively.

Attorney’s Docket No.: 17915-004001

Qo Example 6

Two oil-bearing seeds were extracted by FAMEs prepared from triglycerides obtained from their corresponding oil. sources and triglycerides obtained from another oil source. Specifically, sunflower seeds were extracted by sunflower seed based FAMEs and soybean based FAMESs, and peanuts (ground nuts) were extracted by peanut based

FAMEs and soybean based FAMEs.

Sunflower seeds were extracted with sunflower seed based FAMEs and soybean based FAMEs using a method similar to that described in Example 2 except that a solvent-to-powder ratio of 6:1 was ussed and that only one extraction was performed.

After the extraction with sunflower seed based FAMESs and soybean based FAMEs, the miscella contained a moisture content of 466 and 856 ppm, respectively, a phosphorus content of 10.6 and 12.78 ppm, respe ctively, and an oil content of 6.33 and 4.06 wt%, respectively. The total weight of the extracted oil was 39.0% of that of the sunflower seeds when sunflower seed based FA_MEs were used as the solvent and 24.71% of that of the sunflower seeds when soybean based FAMEs were used as the solvent.

Peanuts were extracted with peanut based FAMEs and soybean based FAMEs using a method similar to that describoed in Example 2 except that the solvent-to-powder ratio was 6:1 and that only one extraction was performed. After the extraction with peanut seed based FAMEs and soybe=an based FAMEs, the miscella contained a moisture content of 470 and 718 ppm, respecti. vely, a phosphorus content of 19.36 and 10.0 ppm, respectively, and an oil content of 6.23 and 6.83 wt%, respectively. The total weight of the extracted oil was 39.1% of that oX the peanuts when peanut based FAMEs were used as the solvent and 39.8% of that of thme peanuts when soybean based FAMEs were used as the solvent.

The above results show that oil could be extracted from a plant seed using

FAMESs prepared from oil of the sam_e plant seed and FAMEs prepared from oil of a different plant seed.

OTHER EMBODIMENTS

All of the features disclosed i n this specification may be combined in any combination. Each feature disclosed in this specification may be replaced by an

Attorney’s Docket No.: 17915-004001 ® alternative feature serving the same, equivalent, or similar purpose. Thus, unless expressly stated otherwise, each feature discl osed is only an example of a generic series of equivalent or similar features.

From the above description, one skilled in the art can easily ascertain the essential characteristics of the present invention, and vvithout departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. Thus, other e mbodiments are also within the scope of the following claims.

Claims

Attorney’s Docket No.: 17915-004001 ® WHAT IS CLAIMED IS:

1. A method of producing a triglyceride solution, comprising contacting a liquid fatty acid alkyl ester and a substance containing triglyceride so that the triglyceride is dissolved into the fatty acid alkyl ester to form a triglyceride solution.

2. The method of claim 1, “wherein the triglyceride-containing substance is from an oil-bearing plant.

3. The method of claim 2, wherein the oil-bearing plant is rice bran, palm fruit pulp, yellowwood, or algae.

4. The method of claim 2, wherein the triglyceride-containing substance is oil-bearing seed.

5. The method of claim 4, wherein the oil-bearing seed is soybean, peanut, sunflower seed, rapeseed, corn, jatroph a seed, karanja seed, neem seed, mahua seed, castor bean, rubber seed, cotton seed, pralm kernel, olive, almond kernel, babassu seed, ben seed, cardoon seed, camelina seed, linseed, hazelnut kernel, hemp seed, mustard seed, jojoba seed, poppy seed, safflower seed, sesame seed, wheat grain, sal seed, crambe seed, cuphea seed, nahor seed, or tobacco seed.

6. The method of claim 1, wherein the fatty acid alkyl ester contains a C6- C24 fatty acid moiety.

7. The method of claim 1, wherein the fatty acid alkyl ester contains a C1-C8 primary or secondary alkoxy moiety.

Attorney’s Docket No.: 17915-004001

®

8. The method of claim 1, wherein the fatty acid alkyl ester is a fatty acid methyl ester, a fatty acid ethyl ester, a fatty acid n-propyl ester, a fatty acid isopropyl ester, a fatty acid n-butyl ester, a fatty acid isobutyl ester, a fatty acid n-pentyl ester, a fatty acid isopentyl ester, a fatty acid neopentyl ester, or a fatty acid n-hexyl ester.

9. The method of claim 1, wherein the fatty acid alkyl ester has a boiling point of 150-500°C.

10. The method of claim 1, wherein the contacting step is conducted at 15- 180°C.

11. The method of claim 10, wherein the Contacting step is conducted at 25- 150°C.

12. The method of claim 1, wherein the fatty acid alky! ester and the triglyceride-containing substance are contacted at a weight ratio ranging from 1:2 to 10:1.

13. The method of claim 1, wherein the fatty acid alkyl ester is obtained, prior to the contacting step, by reacting alcohol with triglyceride extracted from the same triglyceride-containing substance.

14. The method of claim 13, wherein the triglyceride-containing substance is from an oil-bearing plant.

15. The method of claim 14, wherein the oil-bearing plant is rice bran, palm fruit pulp, yellowwood, or algae.

16. The method of claim 14, wherein the triglyceride-containing substance is oil-bearing seed.

Attorney’s Docl=et No.: 17915-004001 [ 17. The method of claim 16, wherein the oil-bearing seed is soybean, peanut, sunflow er seed, rapeseed, corn, jatropha seed, karanja seed, neem seed, mnahua seed, castor bean, rubber seed, cotton seed, palm kernel, olive, almond kernel, babassu seed, ben seed, cardoon seed, camelina seed, linseed, hazelnut kernel, hemp se ed, mustard seed, jo Joba seed, poppy seed, safflower seed, sesame seed, wheat grain, sal seed, crambe seed, cuphea seed, nahor seed, or tobacco seed.

18. The method of claim 17, wherein the fatty acid alkyl ester= contains a C6- C24 fatty acid moiety.

19. The method of claim 18, wherein the alcohol is a C1-C8 primary or secondary alcohol.

20. The method of claim 19, wherein the fatty acid alkyl estem is a fatty acid methyl ester, a fatty acid ethyl ester, a fatty acid n-propyl ester, a fatty acid isopropyl ester, a fatty acid n-butyl ester, a fatty acid isobutyl ester, a fatty acid n-pentyl ester, a fatty ac id isopentyl ester, a fatty acid neopentyl ester, or a fatty acid n-hexyl ester.

21. The method of claim 20, wherein the fatty acid alkyl ester and the triglycesride-containing substance are contacted at a weight ratio ranging from 1:2 to 10:1.

22. The method of claim 21, wherein the contacting step is conducted at 15- 180°C.

23. The method of claim 22, wherein the contacting step is ceonducted at 25- 150°C.

24. The method of claim 13, wherein the fatty acid alkyl estesr contains a C6- C24 fawty acid moiety.

Attorney’s Docket No.: 17915-004001 o 25. The method of claim 13, wherein the alcohol is a C1-C8 primary or secondary alcohol.

26. The method of claim 13, wherein the fatty acid alkyl ester is a fatty acid methyl ester, a fatty acid ethyl ester, a fatty acid n-propyl ester, a fatty acid iso propyl ester, a fatty acidi n-butyl ester, a fatty acid isobutyl ester, a fatty acid n-pentyl ester, a fatty acid isopenttyl ester, a fatty acid neopentyl ester, or a fatty acid n-hexyl ester.

27. The method of claim 13, wherein the fatty acid alkyl ester has a boiling point of 150-500=°C.

28. T he method of claim 13, wherein the contacting step is conducted at 15- 180°C.

29. The method of claim 28, wherein the contacting step is conducted at 25- 150°C.

30. T he method of claim 13, wherein the fatty acid atkyl ester and the triglyceride-containing substance are contacted at a weight ratio ranging from 1:2 to 10:1. _

31.A method of producing a triglyceride solution as claimed in «<laim 1 and substantially as herein descwxibed. DATED THIS A 7th DAY OF MARCH 2006. a hil, HN 2 HAHN APPLICANTS AGENTS