System and process for producing biodiesel fuel with reduced viscosity and a cloud point below thirty-two (32) degrees fahrenheit

• US 6,174,501 B1
• Filed: 03/18/1999
• Issued: 01/16/2001
• Est. Priority Date: 10/31/1997
• Status: Expired due to Term

• Current Assignee: Board of Regents of the University of Nebraska
• Original Assignee: Board of Regents of the University of Nebraska
• Inventors: Noureddini, Hossein
• Primary Examiner(s): Beck, Shrive
• Assistant Examiner(s): NECKEL, ALEXA DOROSHENK
• Application Number:
  US09/271,793
• Time in Patent Office: 670 Days
• Field of Search: 422/188, 422/198, 422/201-205, 422/215, 422/224
• US Class Current: 422/618
• CPC Class Codes: C10L 1/026 for compression ignition
• CPC Class Codes: C11C 3/003 by esterification of fatty acids with alcohols C11C3/02 takes precedence
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

Triglycerides are reacted in a liquid phase reaction with a homogeneous basic catalyst and alcohol, such as ethanol or methanol. The reaction yields a spatially separated two phase result with an upper located non-polar phase consisting principally of transesterified triglycerides and a lower located phase consisting principally of crude glycerol and residual transesterified triglycerides. The transesterified triglycerides and/or glycerol phase is/are optionally, each separately passed through strong cationic ion exchanger(s) to remove anions, resulting in neutral product(s). The crude glycerol is then flashed to remove alcohol and is reacted with an etherifying agent, such as isobutylene or isoamylene, in the presence of a strong acid catalyst to produce glycerol ethers. The glycerol ethers are then added back to the transesterified triglycerides to provide an improved biodiesel fuel.

Claims

1. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit, said oxygenated biodiesel fuel consisting of a mixture of transesterified triglycerides and a cloud-point reducing amount of etherified glycerol;

said system comprising;

a transesterification unit (1);

a transesterified triglycerides/crude glycerol separator unit (2);

optionally a first deionization unit (3″

);

optionally an upper non-polar phase deionization unit (3′

);

optionally a lower phase deionization unit (3);

a first flash unit for separating crude glycerol and alcohol (4);

a reaction unit for etherifying crude glycerol (5); and

functional interconnections;

said transesterification unit (1) having functional input access (A) (B) (C) for entering alcohol and base catalyst and triglycerides thereinto during use;

said transesterification unit (1) having a functional output outlet which is functionally interconnected (E) to a functional inlet access of said transesterified triglycerides/crude glycerol separator unit (2), optionally through (E) (E′

) a first deionization unit (3″

), such that during use alcohol, base catalyst and triglycerides are entered to said transesterification unit (1) and transesterified triglycerides and crude glycerol which are produced in said transesterification unit (1) are caused to pass into said transesterified triglycerides/crude glycerol separator unit (2) through said functional interconnection (E) (E′

) therebetween;

said transesterified triglycerides/crude glycerol separator unit (2) having a functional output outlet for allowing flow of transesterified triglycerides into an output flow outlet (S) which is functionally interconnected (F) thereto, optionally through an upper non-polar phase deionization unit (3′

), and said transesterified triglycerides/crude glycerol separator unit (2) having functional output outlet for allowing flow of glycerol into a functional inlet access of said first flash unit for separating crude glycerol and alcohol (4), which functional inlet access of said first flash unit for separating crude glycerol and alcohol (4) is functionally interconnected (G) to said functional output outlet of said transesterified triglycerides/crude glycerol separator unit (2), said functional interconnection optionally being through (G) (H) a lower phase deionization unit (3), such that during use said transesterified triglycerides/crude glycerol separator unit (2) receives a mixture of transesterified triglycerides and crude glycerol from said transesterification unit (1), effects substantial separation of the transesterified triglycerides therefrom, and passes the substantially separated out transesterified triglycerides to output flow outlet (S) through functional interconnection (F), and passes the crude glycerol, along with remanent alcohol and transesterified triglycerides, to said first flash unit for separating crude glycerol and alcohol (4), through said functional interconnection (G);

said first flash unit for separating crude glycerol and alcohol (4) having a functional output outlet for allowing exit of said alcohol, and functional output outlet for allowing exit of crude glycerol, said functional output outlet for allowing exit of said alcohol optionally being functionally interconnected (I) (I′

) to said transesterification unit (1) functional input access for entering alcohol thereinto such that recycling of alcohol can be achieved during use, and said first flash unit for separating crude glycerol and alcohol (4) functional output outlet for allowing exit of crude glycerol being functionally interconnected (J) to a functional input access of reaction unit for etherifying crude glycerol (5), said reaction unit for etherifying crude glycerol (5) further having functional input access for allowing entry, during use, of a crude glycerol etherifying agent and a functional output outlet for exiting, during use, a mixture of etherified glycerol and remaining glycerol etherifying agent;

said system being adaptable to practice of a process comprising the steps of;

a. providing a quantity of triglycerides;

b. transesterifying at least a portion of said triglycerides to produce a mixture of transesterified triglycerides and crude glycerol;

c. separating out, in an essentially pure state, most of said transesterified triglycerides from said mixture of transesterified triglycerides and crude glycerol, thereby also providing separated-out substantially crude glycerol;

d. optionally diverting a portion of said separated-out substantially crude glycerol;

e. etherifying remaining crude glycerol provided by steps c. and optionally d.; and

f. remixing at least a portion of the resulting glycerol ethers produced in step e., with at least a portion of the step c. separated-out, essentially pure state transesterified triglycerides;

said steps a.-f. serving to produce said oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit, without the required addition of other cloud-point reducing additive(s) and/or glycerol ethers from a source other than that identified in step e.

2. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 1 which comprises a functional interconnection (I) (I′

) between said functional output outlet for allowing exit of alcohol from said first flash unit for separating crude glycerol and alcohol (4), and said transesterification unit (1), so that during use alcohol exiting said functional output outlet for allowing exit of alcohol of said first flash unit for separating crude glycerol and alcohol (4), is recycled as input to said transesterification unit (1).

3. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 1 in which said first deionization unit (3″

) is present.

4. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 1 in which said upper non-polar phase deionization unit (3′

) is present.

5. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 1 in which said lower phase deionization unit (3) is present.

6. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 1 in which are present at least two of the members of the group consisting of:

said first deionization unit (3″

);

said upper non-polar phase deionization unit (3′

); and

said lower phase deionization unit (3).

7. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud point below 32 degrees Fahrenheit as in claim 1 in which the transesterification unit is a selection from the group consisting of:

one or more heated continuously stirred tank reactor(s) (CSTR), and one or more tubular reactor(s) with static mixers.

8. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud point below 32 degrees Fahrenheit as in claim 1, in which the transesterified triglycerides/crude glycerol separator unit (2) consists of a selection from the group consisting of:

a continuous decanter and a centrifuge/clarifier.

9. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud point below 32 degrees Fahrenheit as in claim 1, in which each at least one of the upper non-polar phase deionization unit (3′

) and lower phase deionization unit (3) and first deionization unit (3″

) are present and consist(s) of a selection from the group consisting of;

a continuous ion exchange system as used for practicing Higgins, Ashai, and Fluicon processes, and

two or more resin beds, one or more of which are “

on-line”

while others are “

off-line”

for regeneration.

10. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud point below 32 degrees Fahrenheit as in claim 1, in which at least one of the upper non-polar phase deionization unit (3′

) and lower phase deionization unit (3) and first deionization unit (3″

) is present and contain(s) a strongly acidic hydrogen form macromolecule cationic exchange resins selected from the group consisting of;

Amberlyst-15, and Dowex-50.

11. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud point below 32 degrees Fahrenheit as in claim 1, in which the reaction unit (5) consists of a selection from the group consisting of:

one or more continuously stirred tank reactor(s), reactive distillation reactor(s), and

fixed bed or plug flow reactor(s),

and in which said reaction unit is operated in a mode selected from the the group consisting of;

continuous catalyst regeneration and in regeneration cycles.

12. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud point below 32 degrees Fahrenheit as in claim 1, in which the transesterification unit is a heat exchanger/reactor unit comprised of feed tube(s), each having interior volume surrounded by an outer surface, through which interior volume said quantity of triglycerides, base and methyl alcohol is caused to flow in use, which heat exchange/reactor further includes means for causing steam or heating fluid to flow around the outer surface of said feed tube(s) in use so as to control the temperature of said triglycerides, base and methyl alcohol during passage through said feed tube(s) to the end that transesterification of at least some of said present triglycerides is achieved.

13. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 1,

said system transesterification unit heat comprising a exchanger/reactor comprised of at least one feed tube(s) which have an internal volume and outer surface, through which internal volume of said at least one feed tube(s) a quantity of triglycerides and base catalyst and alcohol is caused to flow in use, said heat exchange/reactor further including means for causing steam or heating fluid to flow around the outer surface of said at least one feed tube(s) in use so as to control the temperature of said triglycerides and base catalyst and alcohol during passage through the internal volume of said at least one feed tube(s) to the end that transesterification of at least some of said triglycerides is achieved, at least one of said heat exchange/reactor unit at least one feed tube(s) having, in said internal volume thereof, a static mixer which remains statically in place as a quantity of triglycerides and base catalyst and methyl alcohol is caused to flow through said internal volume thereof, in use, to the end that said quantity of triglycerides and base catalyst and alcohol are mixed together by interaction therewith.

14. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud point below 32 degrees Fahrenheit as in claim 13, in which said transesterification unit heat exchanger/reactor all of said at least one feed tube(s) contain a

static mixer in said internal volume thereof, which static mixer remains statically in place as a quantity of triglycerides and

base catalyst and methyl alcohol is caused to flow through said internal volume thereof.

15. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit, said oxygenated biodiesel fuel consisting of a mixture of transesterified triglycerides and a cloud-point reducing amount of etherified glycerol

said system comprising:

a transesterification unit (1);

a transesterified triglycerides/crude glycerol separator unit (2);

optionally a first deionization unit (3″

);

optionally an upper non-polar phase deionization unit (3′

);

optionally a lower phase deionization unit (3);

a reaction unit for etherifying crude glycerol (5);

a second flash unit or separating glycerol etherifying agent and etherified glycerol (6);

an extraction unit (7);

optionally a first “

xTBE”

separation unit (9);

optionally a second “

xTBE”

separation unit (9′

); and

functional interconnections;

said transesterification unit (1) having functional input access (A) (B) (C) for entering alcohol and base catalyst and triglycerides thereinto during use;

said transesterification unit (1) having a functional output outlet which is functionally interconnected (E) to a functional inlet access of said transesterified triglycerides/crude glycerol separator unit (2), optionally through (E) (E′

) a first deionization unit (3″

), such that during use alcohol, base catalyst and triglycerides are entered to said transesterification unit (1) and transesterified triglycerides and crude glycerol which are produced in said transesterification unit (1) are caused to pass into said transesterified triglycerides/crude glycerol separator unit (2) through said functional interconnection (E) (E′

) therebetween;

said transesterified triglycerides/crude glycerol separator unit (2) having a functional output outlet for allowing flow of transesterified triglycerides into an output flow outlet (S) which is functionally interconnected (F) thereto, optionally through an upper non-polar phase deionization unit (3′

), and said transesterified triglycerides/crude glycerol separator unit (2) having functional output outlet for allowing flow of glycerol into a functional inlet access of reaction unit for etherifying crude glycerol (5), through functional interconnection (H), said reaction unit for etherifying crude glycerol (5) further having functional input access for allowing entry, during use, of a crude glycerol etherifying agent and a functional output outlet for exiting, during use, a mixture of etherified glycerol and remaining glycerol etherifying agent;

said reaction unit for etherifying crude glycerol (5) functional output outlet for exiting a mixture of etherified glycerol and remaining glycerol etherifying agent being functionally interconnected (K) to a functional input access of said second flash unit or separating glycerol etherifying agent and etherified glycerol (6);

said second flash unit or separating glycerol etherifying agent and etherified glycerol (6) further having a first functional output outlet and a second functional output outlet, said first functional output outlet of said second flash unit or separating glycerol etherifying agent and etherified glycerol (6) being functionally interconnected (M) to the functional access for allowing entry of a crude glycerol etherifying agent into said reaction unit for etherifying crude glycerol (5), optionally through (M) (M′

) said first “

xTBE”

separation unit (9), such that recycling of said crude glycerol etherifying agent can be achieved in use, and said second functional output outlet of said second flash unit or separating glycerol etherifying agent and etherified glycerol (6) being functionally interconnected (L) to a functional input access of said extraction unit (7), optionally through (L) (L′

) said second “

xTBE”

separation unit (9′

), said extraction unit (7) having a second functional input access (P) into which, during use, water is entered for the purpose of effecting substantial separation of di- and tri-ethers and residual methyl esters from a mixture of mono-, di- and tri-ethers of glycerol and glycerol, said extraction unit (7) having a first functional output outlet from which, during use, di- and tri-ethers are exited and caused to be merged with the transesterified triglycerides which exits separator unit (2), said merger being via a functional interconnection (O) which provides functional merger from said extraction unit (7) first functional output outlet to output flow outlet (S);

thereby providing at output flow outlet (S) during use, said oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit, said oxygenated biodiesel fuel consisting of a mixture of transesterified triglycerides and a cloud-point reducing amount of etherified glycerol;

at least one of said optionally present first “

XTBE”

separation unit (9) and optionally present second “

xTBE”

separation unit (9′

), being actually present in said system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit;

said system being adaptable to practice of a process comprising the steps of;

a. providing a quantity of triglycerides;

b. transesterifying at least a portion of said triglycerides to produce a mixture of transesterified triglycerides and crude glycerol;

c. separating out, in an essentially pure state, most of said transesterified triglycerides from said mixture of transesterified triglycerides and crude glycerol, thereby also providing separated-out substantially crude glycerol;

d. optionally diverting a Portion of said separated-out substantially crude glycerol;

e. etherifying remaining crude glycerol provided by steps c. and optionally d.; and

f. remixing at least a portion of the resulting glycerol ethers produced in step e., with at least a portion of the step

c. separated-out, essentially pure state transesterified triglycerides;

said steps a.-f. serving to produce said oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit, without the required addition of other cloud-point reducing additive(s) and/or glycerol ethers from a source other than that identified in step e.

16. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 15 in which said first deionization unit (3″

) is present.

17. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 15 in which said upper non-polar phase deionization unit (3′

) is present.

18. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 15 in which said lower phase deionization unit (3) is present.

19. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 15 in which are present at least two of the members of the group consisting of:

said first deionization unit (3″

);

said upper non-polar phase deionization unit (3′

); and

said a lower phase deionization unit (3).

20. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 15 in which is present said first “

xTBE”

separation unit (9).

21. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 15 in which is present said second “

xTBE”

separation unit (9′

).

22. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 15 in which are present both said first “

xTBE”

separation unit (9) and said second “

XTBE”

separation unit (9′

).

23. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 19, said system transesterification unit comprising a heat exchanger/reactor comprised of at least one feed tube(s) which have an internal volume and outer surface, through which internal volume of said at least one feed tube(s) a quantity of triglycerides and base catalyst and alcohol is caused to flow in use, said heat exchange/reactor further including means for causing steam or heating fluid to flow around the outer surface of said at least one feed tube(s) in use so as to control the temperature of said triglycerides and base catalyst and alcohol during passage through the internal volume of said at least one feed tube(s) to the end that transesterification of at least some of said triglycerides is achieved, at least one of said heat exchange/reactor unit at least one feed tube(s) having, in said internal volume thereof, a static mixer which remains statically in place as a quantity of triglycerides and base catalyst and methyl alcohol is caused to flow through said internal volume thereof, in use, to the end that said quantity of triglycerides and base catalyst and alcohol are mixed together by interaction therewith.

24. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud point below 32 degrees Fahrenheit as in claim 23, in which said transesterification unit heat exchanger/reactor all of said at least one feed tube(s) contain a static mixer in said internal volume thereof, which static mixer remains statically in place as a quantity of triglycerides and base catalyst and methyl alcohol is caused to flow through said internal volume thereof.

25. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit, said oxygenated biodiesel fuel consisting of a mixture of transesterified triglycerides and a cloud-point reducing amount of etherified glycerol

said system comprising:

said transesterification unit (1) having functional input access (A) (B) (C) for entering alcohol and base catalyst and triglycerides thereinto during use;

said transesterification unit (1) having a functional output outlet which is functionally interconnected (E) to a functional inlet access of said transesterified triglycerides/crude glycerol separator unit (2), optionally through (E) (E′

) a first deionization unit (3″

), such that during use alcohol, base catalyst and triglycerides are entered to said transesterification unit (1) and transesterified triglycerides and crude glycerol which are produced in said transesterification unit (1) are caused to pass into said transesterified triglycerides/crude glycerol separator unit (2) through said functional interconnection (E) (E′

) therebetween;

said transesterified triglycerides/crude glycerol separator unit (2) having a functional output outlet for allowing flow of transesterified triglycerides into an output flow outlet (S) which is functionally interconnected (F) thereto, optionally through an upper non-polar phase deionization unit (3′

), and said transesterified triglycerides/crude glycerol separator unit (2) having functional output outlet for allowing flow of glycerol into a functional inlet access of said first flash unit for separating crude glycerol and alcohol (4), which functional inlet access of said first flash unit for separating crude glycerol and alcohol (4) is functionally interconnected (G) to said functional output outlet of said transesterified triglycerides/crude glycerol separator unit (2), said functional interconnection optionally being through (G) (H) a lower phase deionization unit (3), such that during use said transesterified triglycerides/crude glycerol separator unit (2) receives a mixture of transesterified triglycerides and crude glycerol from said transesterification unit (1), effects substantial separation of the transesterified triglycerides therefrom, and passes the substantially separated out transesterified triglycerides to output flow outlet (S) via functional interconnection (F), and passes the crude glycerol, along with remanent alcohol and transesterified triglycerides, to said first flash unit for separating crude glycerol and alcohol (4), through said functional interconnection (G);

said first flash unit for separating crude glycerol and alcohol (4) having a functional output outlet for allowing exit of said alcohol, and functional output outlet for allowing exit of crude glycerol, said functional output outlet for allowing exit of said alcohol optionally being functionally interconnected (I) (I′

) to said transesterification unit (1) functional input access for entering alcohol thereinto such that recycling of alcohol can be achieved during use, and said first flash unit for separating crude glycerol and alcohol (4) functional output outlet for allowing exit of crude glycerol being functionally interconnected (J) to a functional input access of reaction unit for etherifying crude glycerol (5), said reaction unit for etherifying crude glycerol (5) further having functional input access for allowing entry, during use, of a crude glycerol etherifying agent, and a functional output outlet for exiting, during use, a mixture of etherified glycerol and remaining glycerol etherifying agent;

said reaction unit for etherifying crude glycerol (5) functional output outlet for exiting a mixture of etherified glycerol and remaining glycerol etherifying agent being functionally interconnected (K) to a functional input access of said second flash unit or separating glycerol etherifying agent and etherified glycerol (6);

said second flash unit or separating glycerol etherifying agent and etherified glycerol (6) further having a first functional output outlet and a second functional output outlet, said first functional output outlet of said second flash unit for separating glycerol etherifying agent and etherified glycerol (6) being functionally interconnected (M) to the functional access for allowing entry of a crude glycerol etherifying agent into said reaction unit for etherifying crude glycerol (5), optionally through (M) (M′

) said first “

xTBEI”

separation unit (9), such that recycling of said crude glycerol etherifying agent can be achieved in use, and said second functional output outlet of said second flash unit or separating glycerol etherifying agent and etherified glycerol (6) being functionally interconnected (L) to a functional input access of said extraction unit (7), optionally through (L) (L′

) said second “

xTBE”

separation unit (9′

), said extraction unit (7) having a second functional input access (P) into which, during use, water is entered for the purpose of effecting substantial separation of di- and tri-ethers and residual methyl esters from a mixture of mono-, di- and tri-ethers of glycerol and glycerol, said extraction unit (7) having a first functional output outlet from which, during use, di- and tri-ethers and residual methyl esters are exited and caused to be merged with the transesterified triglycerides which exits separator unit (2), said merger being via a functional interconnection (O) which provides functional merger from said extraction unit (7) first functional output outlet to output flow outlet (S);

thereby providing at output flow outlet (S) during use, said oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit, said oxygenated biodiesel fuel consisting of a mixture of transesterified triglycerides and a cloud-point reducing amount of etherified glycerol;

said extraction unit (7) also having a second functional output outlet, for exiting therefrom a mixture of water, mono-, di- and tri-ethers of glycerol and residual methyl ester and glycerol from which has been substantially removed di- and tri-ethers, and entering, through a functional interconnection (N) thereto, said mixture of water, mono-, di- and tri-ethers of glycerol and residual methyl ester and glycerol from which has been substantially removed di- and tri-ethers and residual methyl esters, into a functional input access of said distillation unit (8), said distillation unit (8) further having first and second functional output outlets, such that during use, said distillation unit (8) serves to separate water from said mixture of water, mono-, di- and tri-ethers of glycerol and glycerol from which has been substantially removed di- and tri-ethers and residual methyl ester, and exits said water through said first functional output outlet thereof (R), while remaining mono-, di- and tri-ethers of glycerol and residual methyl ester and glycerol, from which has been substantially removed said water and di- and tri-ethers and residual methyl esters, is exited through said second functional output outlet thereof and is then entered, through a functional interconnection (Q) thereto, into said reaction unit for etherifying crude glycerol (5) along with said crude glycerol etherifying agent;

said system being adaptable to practice of a process comprising the steps of;

a. providing a quantity of triglycerides;

b. transesterifying at least a portion of said triglycerides to produce a mixture of transesterified triglycerides and crude glycerol;

c. separating out, in an essentially pure state, most of said transesterified triglycerides from said mixture of transesterified triglycerides and crude glycerol, thereby also providing separated-out substantially crude glycerol;

d. optionally diverting a portion of said separated-out substantially crude glycerol;

e. etherifying remaining crude glycerol provided by steps c. and optionally d.; and

f. remixing at least a portion of the resulting glycerol ethers produced in step e., with at least a portion of the step c. separated-out, essentially pure state transesterified triglycerides;

said steps a.-f. serving to produce said oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit, without the required addition of other cloud-point reducing additive(s) and/or glycerol ethers from a source other than that identified in step e.

26. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud-point below 32 degrees Fahrenheit as in claim 25, said system transesterification unit comprising a heat exchanger/reactor comprised of at least one feed tube(s) which have an internal volume and outer surface, through which internal volume of said at least one feed tube(s) a quantity of triglycerides and base catalyst and alcohol is caused to flow in use, said heat exchange/reactor further including means for causing steam or heating fluid to flow around the outer surface of said at least one feed tube(s) in use so as to control the temperature of said triglycerides and base catalyst and alcohol during passage through the internal volume of said at least one feed tube(s) to the end that transesterification of at least some of said triglycerides is achieved, at least one of said heat exchange/reactor unit at least one feed tube(s) having, in said internal volume thereof, a static mixer which remains statically in place as a quantity of triglycerides and base catalyst and methyl alcohol is caused to flow through said internal volume thereof, in use, to the end that said quantity of triglycerides and base catalyst and alcohol are mixed together by interaction therewith.

27. A system for practicing a process of producing an oxygenated biodiesel fuel with a cloud point below 32 degrees Fahrenheit as in claim 26, in which said transesterification unit heat exchanger/reactor all of said at least one feed tube(s) contain a static mixer in said internal volume thereof, which static mixer remains statically in place as a quantity of triglycerides and base catalyst and methyl alcohol is caused to flow through said internal volume thereof.