Process for Removing Water and Water Soluble Contaminants From Biofuels

Abstract

Water may be removed from a biofuel or biofuel intermediate by using a demulsifier. The demulsifier includes the product of oxyalkylating a resin prepared from a formulation including a phenol and a compound selected from the group consisting of an aldehyde, a diamine a polyamine and mixtures thereof. The demulsifier may also be used with admixtures of biofuels, biofuel intermediates, or biofuel feedstocks with conventional hydrocarbons.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. provisional Patent Application No. 61/057673 which was filed on May 30, 2008, and which is fully incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a method for clarifying and removing metals from biofuels. The present invention particularly relates to clarifying and removing metals from biodiesel.

BACKGROUND OF THE PRIOR ART

It is well known that as the cost of crude oil increases, numerous efforts have been made to find and develop alternative fuels, particularly fuels that have a renewable, rather than a limited, source. Considerable effort has been expended researching potential fuels from regenerable biological sources, or biofuels. Biodiesel is a diesel fuel-equivalent, processed fuel derived from biological sources (such as vegetable oils), which may be used in unmodified diesel engine vehicles.

In the context herein, biodiesel fuels include, but are not necessarily limited to, alkyl esters of a fatty acid, typically either the ethyl ester or methyl ester of a fatty acid. Thus, many biodiesel fuels may be understood to contain fatty acid methyl esters (FAME). Most biodiesel fuel is presently made by transesterification of fatty triglycerides. Biodiesel fuel may also be made from free fatty acids using an acid catalyst. There are other processes that use an ion-exchange resin catalyst. Most biodiesel fuels are made from vegetable oils, including, but not necessarily limited to rapeseed, soybean, cotton seed, corn, jotropha and the like oils. Some biodiesel is made from animal fats, including, but not limited to beef and pig tallow, chicken fat, fry grease, restaurant trap grease, fish oil, and the like. Efforts are also being made to blend FAME compounds to modify properties such as low temperature handling, for instance esters from palm and soybean oils or soybean and tallow oils (e.g. beef). The mixtures may be complex. All of these fall within the definition of biodiesel fuel herein. Non-esterified or straight vegetable oils (SVO) or straight waste vegetable oil (WVO) is not included in the definition of biodiesel fuels herein. However, biodiesel fuels as defined herein may include these non-esterified SVOs or WVOs in minor proportions (less than 50 volume %, and in another embodiment less than about 1%).

The processing of biofuels is not without problems. For example, many biofuels are less hydrophobic than similar fuels prepared using fossil feedstocks. The presence of the resulting “extra” water can cause problems with processing biofuels and biofuel feedstocks. It may be desirable in the art of preparing biofuels to remove or lessen the concentration of entrained water biofuels and biofuel feedstocks.

SUMMARY OF THE INVENTION

In one aspect, the invention is a process for removing water from a biofuel or biofuel intermediate including admixing the biofuel or biofuel intermediate with a demulsifier wherein the demulsifier includes the product of oxyalkylating a resin prepared from a formulation including a phenol and a compound selected from the group consisting of an aldehyde, a diamine a polyamine and mixtures thereof. The process may also be used with admixtures of biofuels and biofuel intermediates and conventional hydrocarbons.

In another aspect, the invention is a demulsifier useful for removing water and water soluble contaminants from bio-fuels or biofuel intermediates including the product of oxyalkylating a resin prepared from a formulation including a phenol and a compound selected from the group consisting of an aldehyde, a diamine, a polyamine and mixtures thereof.

In still another aspect, the invention is a biofuel prepared using a process including removing water and water soluble contaminants using a demulsifier, the demulsifier including the product of oxyalkylating a resin prepared from a formulation including a phenol and a compound selected from the group consisting of an aldehyde, a diamine, a polyamine and mixtures thereof.

BRIEF DESCRIPTION OF THE FIGURE

The disclosure is best understood with reference to the accompanying FIG. 1 which is a photograph of a three samples of biodiesel, which relate to Examples 1 and 2.

DETAILED DESCRIPTION OF THE INVENTION

In some embodiments of the invention, a biofuel or biofuel intermediate is admixed with a demulsifier wherein the demulsifier includes the product of oxyalkylating a resin prepared from a formulation including a phenol and a compound selected from the group consisting of an aldehyde, a diamine a polyamine and mixtures thereof. For the purposes of this disclosure, the term “a phenol” means the compound phenol, but also certain alkyl phenols having the general formula:

wherein R is an alkyl group having from 1 to 18 carbons and x has a value of from 0 to 2. In some embodiments, the alkyl group, when present, is selected from, but not limited to: butyl, amyl, octyl, nonyl, dinonyl, dodecyl, and the like.

In some embodiments, the resin is prepared with an aldehyde. The aldehyde may have a general formula of:

wherein R¹ is hydrogen or an alkyl group having from 1 to 8 carbons. In some embodiments, the aldehyde is formaldehyde. In other embodiments the aldehyde is acetaldehyde or propionaldehyde.

The diamine or polyamines that may be used with the process of the disclosure may have the general formula:

wherein a and b are integers having a value of from 1 to about 4 and may be the same or different, and y is an integer having a value of from 0 to about 10.

The resin may be prepared using an method known to those of ordinary skill in the art to be useful. For example, the resins useful with the method of the disclosure may be prepared using an acid catalyzed condensation. In one embodiment, the resin may be prepared using nonyl phenol, formaldehyde and ethylene diamine in a Mannich condensation. In another embodiment, the resin is a condensation of phenol and formaldehyde. In still another embodiment, the resin is prepared using a nonyl phenol, formaldehyde and polyamine having the general formula shown above where a and b are 2 and y is 4.

In some embodiments, the resins, prior to oxyalkylation, may have a molecular weight (M_n) of from about 1,000 to about 10,000. In other embodiments, the resin may have a molecular weight (M_n) of from about 2,500 to about 8,000. In still other embodiments, the resin may have a molecular weight (M_n) of from about 3,000 to about 5,000.

The resins are prepared using a phenol and at least one of an aldehyde, a diamine and a polyamine. The resins may be prepared using the phenol and other components in a molar ratio of phenol to (aldehyde and/or diamine and/or polyamine) [phenol:(aldehyde and/or diamine and/or polyamine)] of from 0.8:1 to 1:0.8. In some embodiments, the ratio is about 1:1.

The phenol and aldehyde (and/or amine and/or polyamine) are condensed to produce a resin. In one embodiment, the resin is condensed using an acid catalyst. The acid catalyst may be any known to be useful to those of ordinary skill in the art of preparing such resins. For example, the resins may be prepared using mineral acids or organic acids. In one embodiment, the acid catalyst is selected from the group consisting of H₂SO₄, HCl AlCl₃, H₃PO₄, oxalic acid, SnCl₂, BF₃, BBr₃, BCl₃, para-toluene sulfonic acid, dodecylbenzene sulfonic acid, methane sulfonic acid, trifluoroacetic acid, trichloroacetic acid and mixtures thereof. In some embodiments, the resin may be prepared using a basic catalyst.

In the practice of the processes of the disclosure, the demulsifier includes the product of oxyalkylating a resin. The resin may be oxyalkylated using any method known to those of ordinary skill in the art to be useful. For example, in one embodiment of the invention, a resin may be prepared from a formulation including nonyl phenol, formaldehyde and ethylene diamine. This resin may be then exposed to an alkylene oxide in the presence of a basic catalyst such as potassium hydroxide. The alkylene oxides that may be used with the invention include ethylene oxide, propylene oxide, butylene oxide and mixtures thereof. Any alkylene oxide having from 2 to 8 carbons may be used in some embodiments of the invention. The amount of alkylene oxide used may be from about 0.5 to about 50 moles of alkylene oxide per each mole of phenolic oxygen. In some embodiments, this amount is from about 2 to about 30 moles of alkylene oxide per each mole of phenolic oxygen.

B100 biodiesel may entrain water at a concentration of about 1500 ppm (weight/volume) in some instances. The demulsifier of the disclosure may be used in concentrations sufficient to reduce water or water soluble or dispersed contaminants to a predetermined level. For example, there may be a specification that may be met using the process of the disclosure, such as the 500 ppm water specification required for biodiesel in Europe. While those of ordinary skill in operating a refinery or blending fuels from different sources well know how to determine the optimal concentration for the specifications for processes they are operating, generally speaking, the demulsifiers may be used at a concentration of from about 3 to about 10,000 parts per million (ppm) weight per volume. In some embodiments, the concentration of the demulsifiers used is from about 100 ppm to about 750 ppm. In other embodiments, the demulsifiers are used at a concentration of about 500 ppm.

The demulsifiers of the disclosure may be employed to reduce entrained water in biofuels and biofuel intermediates, the intermediated including biofuel feedstocks. For the purposes of this disclosure, the term biofuels means fuels derived from renewable, non-fossil, feedstocks. The term fossil feedstock refers to crude oil and coal, and the like. For example, oil sand hydrocarbons are an example of a fossil feedstock. The term biofuel feedstocks means materials used to prepare biofuels including, but not limited to vegetable oils and animal fats. Specific biofuel feedstocks include, but are not limited to: palm, rapeseed, soybean, cotton seed, corn, and jotropha oils; and beef, sheep, and pig tallow, chicken fat, fry grease, restaurant trap grease, fish oil, and the like. Biodiesel means a biofuel having physical properties similar to diesel fuel, but derived from non fossil sources possibly including alkyl esters of a fatty acid, typically either the ethyl ester or methyl ester of a fatty acid. Conventional hydrocarbon means hydrocarbons prepare from fossil feedstocks.

Biofuels may be prepared using 100% biofuel feedstocks. For example, biodiesel fuel B100 has a particular definition, including, among other parameters, a minimum ester content of 96.5 wt %. It may be made by transesterifying triglycerides from palm oil, soybean oil, tallow, rapeseed oil and/or waste oils with methanol in the presence of a catalyst.

Biofuels are often available as a blend with fuels originating from fossil sources. Gasoline(s) incorporating various amounts of ethanol are now common, but it would be desirable in the art of refining fossil feedstocks to be able to incorporate heavier biofuel feedstocks into conventional fuel refining processes. One problem with doing so is the entrained water and water soluble and dispersible contaminants often found in biofuels biofuel feedstocks.

In one embodiment of the invention, a biofuel such as a biodiesel, is prepared but rather than being sold as a specialty fuel, it is incorporated into a feed stream within an oil refinery. Prior to being incorporated with the refinery process, the biodiesel is treated with a demulsifier of the disclosure. In one embodiment of this process, the biodiesel is treated with demulsifier and then sent through a centrifuge. In another embodiment, the biodiesel is treated with the demulsifier and then sent through a cyclone separator. In yet another embodiment, the treated biodiesel is held undisturbed and water and condiments are allowed to settle by means of gravity prior to separation from the biodiesel. In one application where a demulsifier is introduced into a tank truck or a tank car prior to shipment, the demulsifier may act to cause entrained water and/or water soluble or dispersed contaminants to coalesce during shipment and then be caught in a filter as the fuel is decanted from the tank.

In another embodiment of the invention, a biofuel intermediate or a biofuel feedstock is first treated with a demulsifier of the disclosure and the included within a refinery process. For example, a process stream resulting from a transesterification process is treated with a demulsifier of the disclosure to remove water and water soluble or dispersible contaminants, and then finished prior to introducing the finished biofuel into an oil refinery process. In still another embodiment, the biofuel intermediate is treated and then introduced into a refinery process stream without finishing.

In yet another embodiment of the invention, a biofuel or biofuel intermediate is introduced into a refinery process stream resulting in a biofuel admixture. At some point prior to a process step that requires very low water or water soluble or dispersible contaminants, such as a catalyst bed or distillation column; the biofuel admixture is treated with a demulsifier of the disclosure.

In still another embodiment of the invention, a biofuel is admixed with a finished hydrocarbon produced from a fossil feedstock such as crude oil. In such embodiments, the admixture of biofuel and fuel produced from fossil feedstocks may be treated with a demulsifier of the invention to remove or lessen the concentration of water and/or water dissolved or dispersed contaminants.

In the practice of some embodiments of the invention, a demulsifier is admixed with biofuels, biofuel feedstocks, biofuel intermediates, and admixtures of these with hydrocarbon process streams and finished hydrocarbons. The demulsifier may be introduced into these admixtures in any way known to be useful to those of ordinary skill in the art. For example, in one embodiment, an admixture of biodiesel and conventional diesel is admixed with an emulsifier by adding the demulsifier to the admixture prior to the admixture passing through a static mixer. In another embodiment, the demulsifier is added to a vessel containing a biofuel that is then stirred using a mixer. In still another embodiment, the demulsifier can be added to the input or exit line of a recirculating pump on a vessel holding a biofuel or biofuel feedstock. In yet another embodiment, the demulsifier may be added to a truck transporting a biofuel or an admixture of hydrocarbons including a biofuel.

The demulsifiers of the disclosure may be used to decrease water concentration in biofuels and biofuel intermediates and feedstocks, but they may also function to reduce or remove water soluble and water dispersible contaminants. Exemplary of such contaminates are: metal salts or oxides, process catalysts, and the like.

The demulsifiers of the disclosure, in addition to the product of oxyalkylating a resin prepared from a formulation including a phenol and a compound selected from the group consisting of an aldehyde, a diamine a polyamine and mixtures thereof; may also include other materials. For example, the demulsifiers may include stabilizers, solvents, and additives.

EXAMPLES

The following examples are provided to illustrate the present invention. The examples are not intended to limit the scope of the present invention and they should not be so interpreted. Amounts are in weight parts or weight percentages unless otherwise indicated.

EXAMPLE 1

A sample of a biodiesel prepared from meth ester palm oil and having a an initial haze rating determined according to ASTM D-4176 of 4 was tested by admixing the sample with the demulsifiers set forth below in Table 1. The resulting haze values and the times noted are also set forth in the tables. A visual comparison is presented in FIG. 1 for Sample A. The Samples used were:

• Sample A is a blend of oxyalkylated acid catalyzed amylphenol resin and oxyalkylated polypropylene glycol available under the trade designation BIO9973 Additive from the Baker Petrolite Corporation;
• Sample B is a blend of oxyalkylated nonylphenol resin and an oxyalkylated acid catalyzed butylphenol resin available under the trade designation BIO-9971 Demulsifier from the Baker Petrolite Corporation;
• Comparative Sample C is a blend of oxyalkylated base catalyzed butyl/nonyl phenol resin, oxyalkylated base catalyzed butylphenol resin, oxyalkylated base catalyzed amylphenol resin, and oxyalkylated polypropylene glycol; and
• Comparative Sample D is an oxyalkylated base catalyzed butyl/nonyl phenol resin.

TABLE 1
	Dosage	Haze Rating @ 16
Additive	(ppm)	hours
Blank	0	3-4
Sample A	500	1-2
Sample B	500	1-2
Sample C	500	2-3
Sample D	500	3-4

TABLE 2
Sample A Haze Rating @ 16
(ppm)    hours
Blank    3-4
100      3
200      2
500      1-2

TABLE 3
	0	15	30	1	2	3	4	24
Sample ID	min	min	min	hr	hr	hr	hr	hr
Sample A	4	3	3	3	3	3	2	1
500 ppm
Haze
Ratings
Blank	4	4	4	4	4	4	4	4
Haze
Ratings

EXAMPLE 2

A sample of a biodiesel prepared from methyl ester palm oil and having a an initial haze rating determined according to ASTM D-4176 of 6 was tested by admixing the sample with the demulsifier set forth below in Table 4. The resulting haze values and the times noted are also set forth in Table 4. A visual comparison is presented in FIG. 1.

TABLE 4
	0	15	30	1	2	3	4	24
Sample ID	min	min	min	hr	hr	hr	hr	hr
Sample A	6	5	5	5	4	4	3	2
500 ppm
Haze
Ratings
Blank	6	6	6	6	6	6	6	6
Haze
Ratings

EXAMPLE 3

Chicken fat was rendered to produce an oil. The resultant oil was treated with methanol and a caustic catalyst at from about 140 to about 145° F. to transesterify the oil to produce a very wet biodiesel. The wet biodiesel was treated with 250 ppm Sample B. The biodiesel cleared very quickly and water coalesced and was collected.

Claims

1. A process for removing water from a biofuel, biofuel intermediate, or biofuel comprising admixing the biofuel or biofuel intermediate with a demulsifier wherein the demulsifier comprises the product of oxyalkylating a resin prepared from a formulation comprising a phenol and a compound selected from the group consisting of an aldehyde, a diamine a polyamine and mixtures thereof.

2. The process of claim 1 wherein the biofuel or biofuel intermediate is admixed with a conventional hydrocarbon.

3. The process of claim 2 wherein the biofuel is a biodiesel.

4. The process of claim 1 wherein the phenol has the general formula:

wherein R is an alkyl group having from 1 to 18 carbons and x has a value of from o to 2.

5. The process of claim 4 wherein the phenol is selected from the group consisting of butyl phenol, amyl phenol, octyl phenol, nonyl phenol, dinonyl phenol, dodecyl phenol, and mixtures thereof.

6. The process of claim 1 wherein the aldehyde has a general formula of:

wherein R1 is hydrogen or an alkyl group having from 1 to 8 carbons.

7. The process of claim 6 wherein the aldehyde is selected from the group consisting of formaldehyde, acetaldehyde, and propionaldehyde.

8. The process of claim 1 wherein the diamine or polyamine has the general formula:

wherein:

a and b are integers having a value of from 1 to about 4 and may be the same or different, and

y is an integer having a value of from 0 to about 10.

9. The process of claim 8 wherein the diamine is ethylene diamine.

10. The process of claim 1 wherein the resin has a molecular weight (Mn) of from about 2,000 to about 10,000.

11. The process of claim 10 wherein the resin has a molecular weight (Mn) of from about 2,500 to about 8,000.

12. The process of claim 1 wherein the resin is prepared in a molar ratio of phenol to (aldehyde and/or diamine and/or polyamine) [phenol:(aldehyde and/or diamine and/or polyamine)] of from 0.8:1 to 1:0.8.

13. The process of claim 12 wherein the molar ratio of phenol to (aldehyde and/or diamine and/or polyamine) [phenol:(aldehyde and/or diamine and/or polyamine)] is about 1:1

14. The process of claim 1 wherein the oxyalkylation of the resin is performed using an alkylene oxide having from 2 to 8 carbons.

15. The process of claim 14 wherein the alkylene oxide is selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide and mixtures thereof.

16. The process of claim 1 wherein the alkylene oxide used is from about 0.5 to about 50 moles of alkylene oxide per each mole of phenolic oxygen in the resin.

17. The process of claim 16 wherein the alkylene oxide used is from about 2 to about 30 moles of alkylene oxide per each mole of phenolic oxygen in the resin.

18. A demulsifier useful for removing water and water soluble contaminants from bio-fuels or biofuel intermediates comprising the product of oxyalkylating a resin prepared from a formulation comprising a phenol and a compound selected from the group consisting of an aldehyde, a diamine, a polyamine and mixtures thereof.

19. A biofuel prepared using a process comprising removing water and water soluble contaminants from the biofuel using a demulsifier, the demulsifier comprising the product of oxyalkylating a resin prepared from a formulation comprising a phenol and a compound selected from the group consisting of an aldehyde, a diamine, a polyamine and mixtures thereof.

20. The biofuel of claim 19 further comprising a conventional hydrocarbon.