WO2014018557A1

WO2014018557A1 - Effective dewatering for biofuel production

Info

Publication number: WO2014018557A1
Application number: PCT/US2013/051730
Authority: WO
Inventors: Eugene Thiers
Original assignee: Sylvan Source, Inc.
Priority date: 2012-07-23
Filing date: 2013-07-23
Publication date: 2014-01-30

Abstract

Embodiments of the invention include dewatering methods that can be deployed in batch or continuous mode and that allow for the physical concentration of biofuel components using phase change techniques that rely on novel heat transfer mechanisms.

Description

EFFECTIVE DEWATERING FOR BIOFUEL PRODUCTION

FIELD OF THE INVENTION

[ 0001 ] The invention disclosed herein generally relates to the field of bio fuel production. In particular, embodiments of the invention relate to systems and methods of removing a substantial fraction of water from the products of fermentation or photo- synthetic algae, so as to facilitate subsequent processing.

BACKGROUND

[ 0002 ] Biofuels can be produced via a range of different technologies. Fermentation and algae photo-synthesis are two major methods of biofuel production currently in competition with each other. Fermentation with yeast, bacteria, or algae yields hydrocarbons, such as alcohols, fatty acids, and simple oils. Algae photo-synthesis yields complex hydrocarbons (including lipids) while sequestering carbon.

[ 0003 ] Both methods require large volumes of water that must be substantially reduced in order to improve subsequent processing. Concentrating the organic fraction is therefore an essential step in biofuel production, either from photosynthesis or fermentation, and lowering the cost of dewatering is critical to making these technologies economically viable and commercially competitive.

SUMMARY OF THE INVENTION

[ 0004 ] The present invention describes various industrial embodiments for an improved system of dewatering of biofuel broths containing dilute hydrocarbons. The system can operate either in batch or continuous mode to remove water from fermentation broths or from oil-water streams deriving from the pressing of photosynthetic algae in the range of 0.2% to more than 30% by weight of hydrocarbons. The system relies on phase change and, in particular, on selective freezing of water to effect water removal and utilizes heat pipes to effectively reduce energy consumption. The thermal insulation characteristics of ice are obviated by super-imposing vibration on the heat pipes at frequencies that promote mechanical resonance. BRIEF DESCRIPTION OF THE DRAWINGS

[ 0005 ] Those of skill in the art will understand that the drawings, described below, are for illustrative purposes only. The drawings are not intended to limit the scope of the present teachings in any way.

[ 0006 ] Figure 1 depicts a schematic diagram of a batch dewatering system.

[ 0007 ] Figure 2 depicts a schematic diagram of a semi-batch dewatering system.

[ 0008 ] Figure 3 depicts a schematic diagram of a continuous dewatering system.

[ 0009 ] Figure 4 depicts schematic diagram of an advanced continuous dewatering system.

DETAILED DESCRIPTION OF THE INVENTION

[ 0010 ] The following references are incorporated herein in their entirety:

[ 0011 ] Lynd, L.R. et al. Curr Opinion in Biotechnology, 16:577-583 (2005); Demain, A.L. et al. Microbiology and Molecular Biology Reviews, 69:124-154 (2005); Lynd, L.R. et al. Microbiology and Molecular Biology Reviews, 66:506- 577 (2002); Brown, M.A. et al. Annual Review of Energy Environment, 23:31-39 (1998); Zaldivar, J. et al. Applied Microbiology and Biotechnology, 56: 17-34 (2001); Wheals, A.E. et al. Trends in Biotechnology, 17:482-487 (1999); Bergquist, P.L. et al. FEMS Microbiology Ecology, 28:99-110 (1999); O'Sullivan, C.A. et al. Biotechnology and Bio engineering, 92:871-878 (2005); Gelhaye, E. et al. Applied and Environmental Microbiology , 59:3154-3156 (1993); Strobel, H.J. et al. Applied and Environmental Microbiology, 61 :4012-4015 (1995); Tomme, P.. et al. Advances in Microbial Physiology, 37: 1-81 (1995); Lynd, L.R. et al. Applied and Environmental Microbiology, 55:3131-3139 (1989); Rani, K.S. et al. Biotechnology Letters, 19:819-823 (1997); Lago, R.C.A. et al. Oleagineux, Paris, France, 40: 147-154 (1985); Ma, F. et al. Bioresource Technology, Elsevier, Great Britain, 70, 1-15 (1999); Tyson, "Biodiesel Technology and Feedstocks," National Renewable Energy Technology, Colorado, pp. 1-37 (2003);.Van Gerpen et al., "Biodiesel Production Technology," Iowa State University, National Renewable Energy Laboratory (NREL)- NREL/SR-510-36244, (Published Jul. 2004); Chasan, Plant Cell, 7:235-237 (1995); Miao et al. Biosource Technology, 97:841-846 (2006); Ge and Wang, Ind. Eng. Chem. Res. 48:2229-35 (2009); Ge and Wang, J. Sol. Chem. 38: 1097-117 (2009). [ 0012 ] Unless otherwise noted, terms are to be understood according to conventional usage by those of ordinary skill in the relevant art.

[ 0013 ] Photosynthesis involving algae normally requires significant volumes of CO₂ and a narrow temperature range, which limits its use in artic or sub-arctic climates. Fermentation, on the other hand, does not require sunlight, can be conducted indoors under more controlled temperature conditions, and yields products that can require less complex processing. Cellulosic fermentation involves plant-based feedstocks and relies on bacteria and/or yeast to convert cellulosic hydrocarbons into alcohols, thus by-passing the oil extraction and additional conversion stage required in algae fermentation.

[ 0014 ] Interest in photosynthetic algae centers mainly on diatoms and cyanobacteria, such as Bacillariophyceae, Botryococcus braunii, Chlorella, Dunaliella tertiolecta, Gracilaria, Pleurochrysis carterae, and Sargassum. The most common oil- producing algae include genera such as Amphipleura, Amphora, Chactoceros, Cyclotella, Cymbella, Flagilaria, Navicula, Hantzschia, Nirzschia, Facodactilum, Thalassiocina, Ankitrodesmus, Botryococcus, Chlorella, Dunaliella, Monoraphidium, Oocystis, Cholococcum, Scenedesmus, Tetraselmis, Oscillatoria, Boekolovia, Isochrysis, Pleurochysis, and Synechococcus .

[ 0015 ] Bio fuel created from cellulosic fermentation of algae into oil carries with it more energy than a similar volume of ethanol. Oil can also be converted to jet fuel, which is not an option for a fuels generated from cellulosic/alcohol processes. Ultimately, deriving fuel from an oil-based product can provide greater energy diversity and efficiency.

[ 0016 ] Cellulose is degraded under anaerobic conditions by a range of physiologically diverse bacteria. These include cellulolytic species, most are which are found within the phyla Thermotogae, Proteobacteria, Actinobacteria, Spirochaetes, Firmicutes, Fibrobacteres, and Bacteroids.

[ 0017 ] The primary reaction for converting oil to biodiesel is called trans- esterification. The trans-esterification process reacts an alcohol with the triglyceride oils contained in vegetable oils, animal fats, or recycled greases, forming fatty acid alkyl esters (biodiesel) and glycerin. The trans-esterification reaction requires heat and a strong base catalyst, such as sodium hydroxide or potassium hydroxide.

[ 0018 ] Regardless of the method used to create feedstock for bio fuel production, there is a common need for removal of excess water prior to further processing. Current techniques for dewatering largely derive from those used in mineral processing and desalination, including filtration and ultra-filtration, reverse osmosis, vacuum evaporators, and the like. These methods are able to increase the concentration of valuable hydrocarbons from fractions of one percent to more than 30% by weight, at which point the organic broth is normally processed by chemical means, including trans-esterification, catalysis, and similar methods. However, integration of these various techniques into a continuous industrial flow is costly given the multiple pieces of equipment and difficult to control. There is a need for dewatering methods that are simpler, that can handle multiple stages of hydrocarbon concentration, and that are less expensive than conventional processes.

[ 0019 ] Embodiments of the invention are disclosed herein, in some cases in exemplary form or by reference to one or more figures. However, any such disclosure of a particular embodiment is exemplary only and is not indicative of the full scope of the invention.

[ 0020 ] Embodiments of the invention include systems, methods, and apparatuses for dewatering biofuel mixtures, particularly those containing alcohols, fatty acids, and lipids. Some embodiments provide a broad spectrum of batch and continuous dewatering systems that do not require cleaning or user intervention over very long periods of time.

[ 0021 ] In some embodiments, the volume of water removed from organic fermentation broths can be at least about 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or more, of the volume of input water. Thus, the system is of particular benefit in conditions in which further processing in, for example, biofuel production, includes a relatively high expense or inconvenience associated with disposing of excess water. The system is significantly more efficient in terms of its concentration of product hydrocarbons per unit of input feed than many other systems.

[ 0022 ] While the ability of any system to remove water from inlet organic mixtures with water is to some extent a function of the composition of the inlet water, systems of the invention described herein are particularly well-suited to remove water from a plurality of different organic solutions, of widely different types, from a single feed stream, producing concentrated organic streams that are suitable for further processing into bio fuels.

[ 0023 ] An exemplary embodiment of the present invention is depicted in Figure 1 and provides a batch method for removing water from biofuel broths. In Figure 1, an aqueous broth containing the products of fermentation or a mixture of organic chemicals, such as alcohols, fatty acids, or lipids, enters the system from a storage tank (1) and flows into a first processing vessel (2) where a number of heat pipes (3) freeze a fraction of the water, thus concentrating the organic broth. The partially concentrated broth then flows into another processing vessel (2) in series with the first vessel, and again a number of heat pipes (3) freeze another fraction of the water. The partial freezing of the broth can be repeated a number of times until the concentrated broth (13) exits the system at levels of concentration in the range of 15-90% organics. The freezing energy for these progressive stages of freezing is provided by heat pipes (3) that transfer the heat of freezing up to a number of refrigerating vessels (5) that are maintained at temperatures below freezing by circulating refrigerating fluids, such as ammonia, and the like, or similar industrial refrigerants, such as chlor-fluoro compounds, ice-salt mixtures, dry-ice and acetone mixtures, and the like. The spent refrigerant is then returned to a refrigerating loop by a line (6).

[ 0024 ] In a further aspect, after the organic broth has been concentrated, the system can be allowed to warm so as to allow the ice formed during broth concentration to melt and accumulate at the bottom of a vessel (5), where a valve allows the waste water (7) to exit the system via a collection line (8).

[ 0025 ] A discussion of heat pipes for transferring thermal energy from one end of a heat pipe to the other is provided in US Patent Application No: 12/090,248, entitled ENERGY-EFFICIENT DISTILLATION SYSTEM, filed April 14, 2008, US Provisional Patent Application No: 60/727,106, entitled ENERGY-EFFICIENT DISTILLATION SYSTEM, filed October 14, 2005, and PCT application no PCT/US09/57277, entitled LARGE-SCALE WATER PURIFICATION AND DESALINATION, filed September 17, 2008, all of which are incorporated herein by reference in their entirety.

[ 0026 ] Figure 2 depicts a semi-batch configuration for dewatering mixtures of hydrocarbons in water. In Figure 2, an aqueous broth containing the products of fermentation or a mixture of organic chemicals, such as alcohols, fatty acids, or lipids, enters the system from a storage tank (1) and flows into a pump (11) and a control valve (12) and therefrom into a first processing vessel (2) where a number of heat pipes (3) freeze a fraction of the water, thus concentrating the organic broth. The concentrated broth then flows into another control valve and from there into a second processing vessel where heat pipes again freeze another fraction of the water, thus further concentrating the organic broth. The concentrated broth exits the system at the bottom of the second processing vessel (13). Following this initial concentration stage, the refrigerant from a tank (9) is shut off by the control valve (12), and a similar control valve allows warm water from a tank (10) to flow into a thermal vessel (5), thus providing a source of heat to heat pipes (3), which melt the water ice produced during the earlier freezing cycle. The melted waste water exits each processing vessel at the bottom (7), and a new cycle of freezing can begin.

[ 0027 ] Figure 3 depicts an exemplary embodiment for the continuous dewatering of biofuels. In Figure 3, an aqueous broth containing the products of fermentation or a mixture of organic chemicals, such as alcohols, fatty acids, or lipids, enters the system from a storage tank (1) and sequentially flows into a number of processing vessels (2) via control valves (12). As the organic broth flows through the processing vessel (2), heat pipes (3) proceed to freeze a fraction of the broth in the form of water ice, thus progressively concentrating the organic content of the broth and allowing it to discharge at the end of the processing vessel (13). Following this initial freezing and concentration stage, a control valve (12) in the upper processing vessel is shut-off Simultaneously, the control valve (12) at the exit of refrigerant tank (9) is also closed, while a similar control valve (12) in the warm water tank (10) is open, thus allowing the elongated thermal vessel (5) to warm and thereby transmit heat to the heat pipes (3), which transfer such heat and melt the ice previously collected during the freezing cycle, resulting in the discharge of waste water (7) from the processing vessel.

[ 0028 ] An important element in all of these embodiments is the freezing point depression, which is the phenomenon in which the freezing point of a solvent is depressed by the amount of solute dissolved in it. The magnitude of the change in the freezing point depends on the concentration of the solute and can be calculated for the case of an ideal solution by a simple linear relationship with the cryoscopic constant, according to the following equation:

AT_F = K_F ' b ' i

[ 0029 ] In the equation above, Δ T_F relates to the freezing point depression and is defined as T_F (pure solvent) - T_F (solution); K_F is the cryoscopic constant and is dependent on the properties of the solvent, not the solute; b is the molality (moles solute per kg of solvent); i is the van 't Hoff factor, or the number of ion particles per individual molecule of solute {e.g. i = 2 for NaCl).

[ 0030 ] Because this simple relation doesn't include the nature of the solute, the equation above is only effective in dilute solution. For a more accurate calculation at a higher concentration, Ge and Wang (Ge and Wang, Ind. Eng. Chem. Res. 48:2229-35 (2009); Ge and Wang, J. Sol. Chem. 38: 1097-117 (2009)) have proposed a new equation: ATF = {Ati^usT_F - 2RT_F*lna_liq - [2AC^fus _pT_F ²Mna_liq +

/[2( H^fus _TF/ T_F +

0.5AC^fus _p-Rlna_Uq)]

[ 0031 ] In the above equation, T_F is the normal freezing point of the pure solvent (0°C for water, for example); <¾ is the activity of the solution (water activity for aqueous solution); Af ^UST_F is the enthalpy change of fusion of the pure solvent at T_F, which is 333.6 J/g for water at 0°C; AC^&S _P is the difference of heat capacity between the liquid and solid phases at T_F, which is 2.11 J/g/K for water.

[ 0032 ] These estimates of the freezing point depression assume, as noted, an ideal solution and equilibrium conditions, factors that are seldom achieved in the real world. However, the fact that equilibrium conditions and ideal solutions are seldom encountered in practice actually helps in the case of the present invention, as it provides additional driving force to a preferred dynamic embodiment as described in Figure 4, which is described next.

[ 0033 ] In Figure 4, an aqueous broth containing the products of fermentation or a mixture of organic chemicals (1), such as alcohols, fatty acids, or lipids, enters the system and sequentially flows into a number of processing vessels (2) that are vertically stacked. As the organic broth flows through the processing vessel (2), heat pipes (3) proceed to freeze a fraction of the broth in the form of water ice, thus progressively concentrating the organic content of the broth and allowing it to discharge through a downcomer tube (14) into a lower processing vessel, where other heat pipes progressively freeze another fraction of the water into ice.

[ 0034 ] The ice is continuously dislodged from the surface of the heat pipes (3) by applying electromechanical vibration (15) to such heat pipes at a frequency that promotes mechanical resonance in the heat pipe, thereby causing the ice to slurry near the surface of the processing vessel (2), so it can be continuously discharged into a lower processing vessel via downcomer tube (14). Once the broth has cascaded down to the lowest processing vessel (2) and is sufficiently concentrated in organics, it exits the vertically stacked vessels near the bottom and flows into a settling tank (16), where the ice slurry separates into a surface layer to be discharged as a waste stream and a stream of concentrated broth (13).

[ 0035 ] The electromechanical vibration (15) that is applied to the heat pipes (3) can be from any conventional type, as long as its frequency is close to the resonance frequency of the heat pipes, or a fraction thereof. [ 0036 ] Energy for maintaining the freezing phenomena across the various processing vessels (2) is provided by a cryogenic or refrigerant source (9) at the bottom of the vertical stack, and heat pipes (3) provide the heat transfer mechanism for keeping a temperature differential (ΔΤ) between individual processing vessels on the order of a few degrees centigrade, with progressively warmer temperatures near the top of the processing stack.

[ 0037 ] Sources of refrigerant or cryogenic fluids (9) that provide the energy for the progressive freezing reactions can be of any type consistent with the temperature gradient required across the vertical stack of processing vessels (2), including but not limited to mixtures of ice and common salt, refrigerating ammonia, mixtures of dry ice (frozen C0₂) with acetone, and the like.

[ 0038 ] Heat pipes (3) suitable for the present invention include those that can operate at or below the freezing point of water (0°C). Cryogenic heat pipes typically have working fluids different from water, such as ammonia or methanol, and are commercially available.

[ 0039 ] An important element in the embodiment of Figure 4 is the fact that the system is not at thermal equilibrium. Rather, non-equilibrium conditions allow the system as configured to operate optimally. For example, the fact that each processing vessel in the vertical stack has a temperature difference with the vessel above or below allows the heat pipes to transfer the energy necessary for freezing a fraction of the water at each stage. Likewise, this same temperature difference is what allows a given fraction of water to freeze according to the freezing point depression mentioned above because as water turns into ice, the concentration of organic solute in the aqueous broth increases, thus further depressing the freezing point for the lower processing stage. Lastly, it is the non-equilibrium condition in the system that allows control of the system, primarily as a function of the incoming flow rate or throughput rate. Thus, the flow rate of the incoming broth determines the residence time of the broth in each processing stage and therefore the time for ice to form on the heat pipes and consequently the increase in the concentration of organics in the broth.

[ 0040 ] The invention described herein suitably can be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions indicates the exclusion of equivalents of the features shown and described or portions thereof.

[ 0041] Having described the invention in detail, it will be apparent that modifications, variations, and equivalent embodiments are possible without departing the scope of the invention disclosed herein. Furthermore, it should be appreciated that all examples in the present disclosure are provided as non-limiting examples. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art and that such modifications and variations are considered to be within the scope of this invention as defined by the disclosure.

[ 0042 ] Those skilled in the art recognize that the aspects and embodiments of the invention set forth herein can be practiced separate from each other or in conjunction with each other. Therefore, combinations of separate embodiments are within the scope of the invention as disclosed herein.

[ 0100 ] The various methods and techniques described above provide a number of ways to carry out the application. Of course, it is to be understood that not necessarily all objectives or advantages described can be achieved in accordance with any particular embodiment described herein. Thus, for example, those skilled in the art will recognize that the methods can be performed in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objectives or advantages as taught or suggested herein. A variety of alternatives are mentioned herein. It is to be understood that some preferred embodiments specifically include one, another, or several features, while others specifically exclude one, another, or several features, while still others mitigate a particular feature by inclusion of one, another, or several advantageous features.

[ 0101] Furthermore, the skilled artisan will recognize the applicability of various features from different embodiments. Similarly, the various elements, features and steps discussed above, as well as other known equivalents for each such element, feature or step, can be employed in various combinations by one of ordinary skill in this art to perform methods in accordance with the principles described herein. Among the various elements, features, and steps some will be specifically included and others specifically excluded in diverse embodiments. [0102] Although the application has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the embodiments of the application extend beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and modifications and equivalents thereof.

[0103] In some embodiments, the numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth, used to describe and claim certain embodiments of the application are to be understood as being modified in some instances by the term "about." Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the application are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable.

[0104] In some embodiments, the terms "a" and "an" and "the" and similar references used in the context of describing a particular embodiment of the application (especially in the context of certain of the following claims) can be construed to cover both the singular and the plural. The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (for example, "such as") provided with respect to certain embodiments herein is intended merely to better illuminate the application and does not pose a limitation on the scope of the application otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the application.

[0105] Preferred embodiments of this application are described herein, including the best mode known to the inventors for carrying out the application. Variations on those preferred embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. It is contemplated that skilled artisans can employ such variations as appropriate, and the application can be practiced otherwise than specifically described herein. Accordingly, many embodiments of this application include all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the application unless otherwise indicated herein or otherwise clearly contradicted by context.

[ 0106 ] All patents, patent applications, publications of patent applications, and other material, such as articles, books, specifications, publications, documents, things, and/or the like, referenced herein are hereby incorporated herein by this reference in their entirety for all purposes, excepting any prosecution file history associated with same, any of same that is inconsistent with or in conflict with the present document, or any of same that may have a limiting affect as to the broadest scope of the claims now or later associated with the present document. By way of example, should there be any inconsistency or conflict between the description, definition, and/or the use of a term associated with any of the incorporated material and that associated with the present document, the description, definition, and/or the use of the term in the present document shall prevail.

[ 0107 ] In closing, it is to be understood that the embodiments of the application disclosed herein are illustrative of the principles of the embodiments of the application. Other modifications that can be employed can be within the scope of the application. Thus, by way of example, but not of limitation, alternative configurations of the embodiments of the application can be utilized in accordance with the teachings herein. Accordingly, embodiments of the present application are not limited to that precisely as shown and described.

Claims

CLAIMS What is claimed is:

1. A method of concentrating biofuels that relies on phase separation and on the progressive freezing of water from organic broths containing alcohols, fatty acids, or lipids in aqueous solutions.

2. The method of claim 1, wherein the progressive concentration of organics in the broth is accomplished in a batch system that utilizes heat pipes as the means of heat transfer from a refrigerant to the broth.

3. The method of claim 1, wherein the refrigerant is cryogenic ammonia, a mixture of ice and salt, or similar refrigerant fluid.

4. The method of claim 1, wherein the system is periodically allowed to warm in order to melt the accumulated ice and discharge it as waste water.

5. The method of claim 1, wherein the progressive concentration of organics in the broth is accomplished in a semi-batch system that utilizes heat pipes as the means of heat transfer from a refrigerant to the broth and from warm water to melt ice.

6. The method of claim 5, wherein the refrigerant is cryogenic ammonia, a mixture of ice and salt, or similar refrigerant fluid.

7. The method of claim 5, wherein the ice that forms in the system is periodically removed by switching heat from warm water into the heat pipes in order to melt the accumulated ice and discharge it as waste water.

8. The method of claim 1, wherein the progressive concentration of organics in the broth is accomplished in a continuous system that utilizes heat pipes as the means of heat transfer from a refrigerant to the broth and from warm water to melt ice.

9. The method of claim 8, wherein the refrigerant is cryogenic ammonia, a mixture of ice and salt, or similar refrigerant fluid.

10. The method of claim 8, wherein the ice that forms in the system is periodically removed by switching heat from warm water into the heat pipes in order to melt the accumulated ice and discharge it as waste water.

11. The method of claim 1 , wherein the progressive concentration of organics in the broth is accomplished in a continuous system that utilizes a vertical stack of processing vessels that utilizes heat pipes as the means of heat transfer from a refrigerant to the broth and from warm water to melt ice, and that continuously cascades the broth from top to bottom in the form of a slurry with ice.

12. The method of claim 11, wherein the concentrated broth exits the system at the bottom into a settling tank that separates the ice from the concentrated organic broth.

13. The method of claim 11, wherein the refrigerant is cryogenic ammonia, a mixture of ice and salt, or similar refrigerant fluid.

14. The method of claim 11, wherein individual processing vessels have a downcomer tube that continuously transfers the broth and ice slurry into a lower vessel.

15. The method of claim 11, wherein the heat pipes are vibrated with an electromechanical device that causes resonance in the heat pipes to continuously dislodge ice as it forms.

16. The method of claim 11, wherein control of the system is achieved by adjusting the flow rate of the incoming broth in relation to the volume of the processing vessels and the number and surface area of the heat pipes to provide the required residence time for the progressive concentration of the broth.

17. An apparatus for concentrating bio fuels that relies on phase separation and specifically on the progressive freezing of water from organic broths containing alcohols, fatty acids, or lipids in aqueous solutions.

18. The system of claim 17, wherein the concentration of the broth is accomplished in a batch system consisting of a series of processing vessels that remove water by freezing with heat pipes connected to a refrigerant fluid.

19. The system of claim 17, wherein the concentration of the broth is accomplished in a semi-batch system consisting of a series of processing vessels that remove water by freezing with heat pipes connected to a refrigerant fluid, and wherein the ice is periodically melted by switching the refrigerant to a warm fluid.

20. The system of claim 17, wherein the concentration of the broth is accomplished in a continuous system consisting of a series of processing vessels that remove water by freezing with heat pipes connected to a refrigerant fluid, and wherein the ice is periodically melted by switching the refrigerant to a warm fluid.

21. The system of claim 17, wherein the concentration of the broth is accomplished in a continuous system consisting of a vertical stack of processing vessels that remove water by freezing with heat pipes connected to a refrigerant fluid, and wherein the ice is continuously dislodged with electromechanical vibration that induces resonance in the heat pipes.

22. The system of claim 17, wherein control of the system is accomplished by adjusting the flow rate of the broth such as to provide a residence time sufficient for ice formation and subsequent dislodging and consistent with freezing point depression and the required concentration of organics in the broth.