GLYCERINE COMPOSITION

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims the benefit under 35 U.S.C. §119(e) of provisional patent application S.N. 61/282,949, filed April 28, 2010, the contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

[0002] The present invention relates to a process for extracting a fatty acid alkyl ester from a crude glycerine composition.

DESCRIPTION OF THE PRIOR ART

[0003] As a result of the continuing rise in the cost of fossil fuels, there has been an increasing interest in biodiesel fuels as a supplement to or replacement for traditional fossil fuel sources. Biodiesel processing involves the production of alkyl esters of long chain fatty acids by reacting the source acid with a low molecular weight alcohol, such as methanol (i.e., methylation in the case of methanol).

[0004] A conventional process for manufacturing fatty acid alkyl esters involves the transesterification of triglycerides (e.g., from animal fat sources or any other sources of (tri)glycerides) using methanol, in the presence of an alkali catalyst (caustic soda). In addition to the desired fatty acid alkyl esters, this process produces a so-called glycerine effluent stream comprising glycerine (glycerol), excess alcohol, residual fatty acid alkyl ester, a mixture of mono-, di- and tri-glycerides resulting from the transesterification step, salts and other minor components.

[0005] There are at least two areas in need of improvement. [0006] First, one of the components of the glycerine stream is residual fatty acid alkyl ester. This is the desired biofuel product. Accordingly, it would be desirable to have a process for separating the residual fatty acid alkyl ester from the glycerine stream thereby yielding a valuable supplemental source of the desired biofuel product. [0007] Second, the rapid worldwide expansion in the production of biodiesel fuel since 2000 has created a fast growing supply of byproduct crude glycerine. One of the applications for glycerine is in the production of isocyanate-based polymer foams - e.g., polyurethane foams. One of the problems of using the crude glycerine stream from a biofuel product process is that the presence of fatty acid alkyl ester in the crude glycerine stream often renders the crude glycerine stream incompatible with the chemical systems used to produce the isocyanate-based polymer foams. Specifically, it is believed that the relatively high salt content (e.g., sodium sulfate) in the crude glycerine stream serves to contribute to the incompatible of the latter with the chemical systems conventionally used to produce polyurethane foam. [0008] It would therefore be desirable to provide a low cost efficient process for purification of glycerine recovered from fatty acid alkyl ester processes, such as the manufacture of biodiesels. Such a process would also provide an efficient low cost means for recovering additional fatty acid alkyl ester on the one hand while improving the compatibility of the glycerine stream with the chemical systems used to produce isocyanate-based foams such as polyurethane foams. In addition, it would be highly desirable if the process could be implemented utilizing predominately commonly available equipment such as might be available from idle facilities or surplus equipment previously used for other purposes. Thus, a goal of the present invention is to provide a relatively simple, low-cost process for purifying glycerine byproduct from biodiesel production so as to efficiently improve the the over all yield of fatty acid alkyl ester (the biofuel component) while concurrently improving the quality of the byproduct glycerine stream so as to improve the compatability thereof with the chemical systems used to produce isocyanate-based polymer foams such as polyurethane foams. SUMMARY OF THE INVENTION

[0009] It is an object of the present invention to obviate or mitigate at least one of the above-mentioned disadvantages of the prior art.

[0010] It is another object of the present invention to provide a novel process for extracting a fatty acid alkyl ester from a crude glycerine composition.

[0011] Accordingly, in one of its aspects, the present invention provides a process for extracting a fatty acid alkyl ester from a crude glycerine composition, the process comprising the steps of:

(a) adding an aqueous liquid to the crude glycerine composition to cause phase separation to produce at least two phases comprising an organic phase and an aqueous phase;

(b) separating the organic phase from the aqueous phase; and

(c) separating the fatty acid alkyl ester from the organic phase.

[0012] Thus, the present inventors have discovered that it is possible to extract fatty acid alkyl ester from a crude glycerine composition by combining the crude glycerine composition with an aqueous liquid. When preferred amounts of aqueous liquid and temperature are used, it is possible to extract a significant amount of residual fatty acid alkyl ester from the crude glycerine composition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0013] In one of its aspects, the present invention relates to a process for extracting a fatty acid alkyl ester from a crude glycerine composition. Preferred embodiments of the process may include any one or a combination of any two or more of any of the following features: the crude glycerine composition may be derived from animal fat that has been subjected to at least one treatment step; the at least one treatment step may comprise digestion with caustic soda to produce an intermediate composition comprising fatty acid and glycerine; the intermediate composition may be subjected to an alkylation step to produce produce the crude gycerin composition; the intermediate composition may be subjected to a neutralization step followed by an alkylation step to produce the crude gycerin composition; the crude glycerine composition comprises a fatty acid alkyl ester, glycerine and at least one salt selected from the group consisting of alkali metal salts and alkaline earth metal salts; the crude glycerine composition may comprise a fatty acid alkyl ester, glycerine and at least one salt selected from the group consisting of alkali metal salts and alkaline earth metal salts; the crude glycerine composition may comprise a fatty acid alkyl ester, glycerine and at least one alkali metal salt; the crude glycerine composition may comprise a fatty acid alkyl ester, glycerine and at least one sodium salt; the crude glycerine composition may comprise a fatty acid alkyl ester, glycerine and sodium sulphate;

Step (a) in the process may comprise adding an aqueous liquid to the crude glycerine composition to cause phase separation to produce three phases comprising an organic phase, an aqueous phase and a solids phase; • the solids phase may comprise at least one salt selected from the group consisting of alkali metal salts and alkaline earth metal salts;

• the solids phase may comprises an alkali metal salt;

• the solids phase may comprise a sodium salt;

• the solids phase may comprise sodium sulphate;

• Step (a) in the process may be conducted with agitation;

• Step (a) in the process may be conducted with mechanical agitation;

• Step (a) in the process may be conducted with mechanical stirring;

• Step (a) in the process may be conducted with centrifugal agitation;

• Step (a) in the process may be conducted with ultrasonic agitation;

• Step (a) in the process may be conducted at a temperature in the range of from about 10° to about 100°C;

• Step (a) in the process may be conducted at a temperature in the range of from about 15° to about 95°C;

• Step (a) in the process may be conducted at a temperature in the range of from about 20° to about 90°C;

• Step (a) in the process may be conducted at a temperature in the range of from about 20° to about 70°C

• Step (a) in the process may be conducted at a temperature in the range of from about 20° to about 55°C;

• Step (a) in the process may be conducted at a temperature in the range of from about 20° to about 40°C; Step (a) in the process may be conducted at a temperature in the range of from about 20° to about 30°C;

Step (a) in the process may be conducted at a temperature in the range of from about 20° to about 25°C;

Step (a) in the process may be conducted at a temperature of about 20°C;

Step (a) in the process may be conducted at a temperature of about 90°C; the amount of aqueous liquid used in Step (a) may be in the range of from about 10 parts by weight to about 5 parts by weight per 400 parts by crude glycerine composition; the amount of aqueous liquid used in Step (a) may be in the range of from about 10 parts by weight to about 5 parts by weight per 300 parts by crude glycerine composition; the amount of aqueous liquid used in Step (a) may be in the range of from about 10 parts by weight to about 5 parts by weight per 200 parts by crude glycerine composition; the amount of aqueous liquid used in Step (a) may be in the range of from about 10 parts by weight to about 5 parts by weight per 150 parts by crude glycerine composition; the amount of aqueous liquid used in Step (a) may be in the range of from about 10 parts by weight to about 5 parts by weight per 100 parts by crude glycerine composition; the amount of aqueous liquid used in Step (a) may be in the range of from about 10 parts by weight to about 70 parts by weight per 100 parts by crude glycerine composition; • the amount of aqueous liquid used in Step (a) may be in the range of from about 15 parts by weight to about 70 parts by weight per 100 parts by crude glycerine composition;

• the amount of aqueous liquid used in Step (a) may be in the range of from about 15 parts by weight to about 65 parts by weight per 100 parts by crude glycerine composition;

• the amount of aqueous liquid used in Step (a) may be in the range of from about 15 parts by weight to about 45 parts by weight per 100 parts by crude glycerine composition;

• the amount of aqueous liquid used in Step (a) may be in the range of from about 15 parts by weight to about 40 parts by weight per 100 parts by crude glycerine composition;

• the fatty acid alkyl ester may comprise a fatty acid methyl ester; and/or

• the aqueous liquid may be water.

[0014] Embodiments of the present invention will be illustrated with reference to the following non-limiting examples which should not be used to construe the scope of the invention.

EXAMPLES 1-9

[0015] The starting material used in these Examples was a crude glycerine composition obtained from a biofuel production process. The crude glycerine composition contained the components set out in Table 1. Table 1

[0016] To a 600 mL beaker was added 200 g of the crude glycerine composition. At ambient temperature (25 °C), water in the amount shown in Table 2 was added to the beaker and the contents of the beaker were transferred to a high shear mixture operated at at 3000 rpm. Stirring was continued for the shorter of 15 minutes or when it appeared that components were beginning to separate (even with stirring).

[0017] The time to achieve separation of the mixture to three distinct layers is reporting in Table 2. The three distinct layers consisted of

(a) a top, organic liquid phase containing the fatty acid methyl ester;

and

(b) a middle, aqueous liquid phase containing glycerol, water,

methanol and water soluble salts; and

(c) a bottom, solid layer containing sodium sulfate and other water

insoluble salts and organic solids.

Further, the amount of fatty acid methyl ester recovered from the top, organic liquid phase, together with the percent recovery based on the original constitution of the starting crude glycerine composition, is also reported in Table 2. [0018] The results in Table 2 illustrate that a significant amount of fatty acid methyl ester was recoverd in Examples 5-9, particularly in Example 6. The results in Table 2 also show that that a significant about of sodium sulfate originally contained in the starting crude glycerine composition was in fact separated from that composition. Thus, the fatty acid methyl ester recovered can be used as a valuable fuel source while the residual glycerine composition is expected to be more compatible with the chemical systems used to make polyurethane foams since the residual glycerine composition has a significantly reduced amount of sodium sulfate.

EXAMPLES 10-19 [0019] Unless otherwise noted in Table 3, to a 600 mL beaker containing a high shear mixer was added 200 g of the same crude glycerine composition used in Examples 1-9. The crude glycerine composition was heat to approximately 90°C using a hot plate with high shear mixer being operated at approximately 3000 rpm. Ambient temperature (25°C) water was added to the beaker in the amount shown in Table 3. The was observed as decreasing and the contents of the beaker were heated to 90°C using the hot plate with high shear mixer being operated at approximately 3000 rpm. Stirring was continued for the shorter of 15 minutes or when it appeared that components were beginning to separate (even with stirring).

[0020] The time to achieve separation of the mixture to three distinct layers (as described above in relation to Examples 1-9) is reported in Table 3. Further, the amount of fatty acid methyl ester recovered from the top, organic liquid phase, together with the percent recovery based on the original constitution of the starting crude glycerine composition, is also reported in Table 3.

[0021] The results in Table 2 illustrate that a significant amount of fatty acid methyl ester was recoverd in Examples 15-19, particularly in Example 18. As with Table 2, the results in Table 3 also show that that a significant about of sodium sulfate originally contained in the starting crude glycerine composition was in fact separated from that composition. Again, the fatty acid methyl ester recovered can be used as a valuable fuel source while the residual glycerine composition is expected to be more compatible with the chemical systems used to make polyurethane foams since the residual glycerine composition has a significantly reduced amount of sodium sulfate.

[0022] While this invention has been described with reference to illustrative embodiments and examples, the description is not intended to be construed in a limiting sense. Thus, various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. For example, while reference has been made to the use of a crude gylcerine composition derived from animal fat sources, the crude glycerine composition useful in the present process may be derived from any other source of (tri)glycerides. Further, while reference was made in the Examples to the use of agitation via a high shear mixer, it is possible to use other modes of agititation (vigorous or non- vigorous) in the present process. Still further, while a specific crude glycerine composition was used in the Examples to illustrate embodiments of the invention, those of skill in the art will recognize that the present process may be used with other crude glyrcerin compositions having varying components and/or relative amounts of components compared to the crude glycerine composition used in the Examples. It is therefore contemplated that the appended claims will cover any such modifications or embodiments.

[0023] All publications, patents and patent applications referred to herein are incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety. Table 2

Notes: (1) "pphp" = part by weight per 100 parts by weight of the starting crude glycerine composition

(2) Based on starting crude glycerine composition containing 5 weight percent FAME

(3) Recovered from solid phase 15 weight percent Na ₂ S0 ₄

(4) Based on starting crude glycerine composition containing 15 weight percent Na ₂ S0 ₄

Table 3

Notes: ( 1 ) "pphp" = part by weight per 100 parts by weight of the starting crude glycerine composition

(2) Based on starting crude glycerine composition contained 5 weight percent FAME

(3) Recovered from solid phase 15 weight percent Na ₂ S0 ₄

(4) Based on starting crude glycerine composition containing 15 weight percent Na ₂ S0 ₄

(5) Procedure modified to use 400 g of starting crude glycerine composition

(6) Procedure modified to use 300 g of starting crude glycerine composition