BIODIESEL COLD FILTRATION PROCESS

Abstract

An improved biodiesel production process includes the steps of processing a feedstock to produce biodiesel, cooling the biodiesel so as to form sediment, and filtering the biodiesel to remove the sediment. The resulting biodiesel from the cold filtration process avoids problems of sediment formation during storage and transportation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a preferred embodiment of the biodiesel production process according to the present invention.

FIG. 2 is a schematic view showing a preferred embodiment of the cold filtration step in the biodiesel production process of the present invention.

Claims

1. A method for removing impurities from biodiesel, comprising: converting a feedstock into biodiesel having a temperature exceeding 98° C.;cooling the biodiesel to a temperature range sufficient to form particulates of impurities; andfiltering the cooled biodiesel to remove the particulates.

2. The method of claim 1 whereby the biodiesel is cooled to a temperature of less than about 38° C.

3. The method of claim 2 whereby the biodiesel is cooled to a temperature of between about 4-38° C.

4. The method of claim 1 wherein the cooling step is performed in multiple stages using a series of heat exchangers.

5. The method of claim 4 further comprising periodically cleaning the heat exchangers by running un-cooled biodiesel through the heat exchangers without supplying cooling fluid to the exchangers.

6. The method of claim 4 wherein a first cooling stage reduces the biodiesel temperature to approximately 93-105° C., a second cooling stage further reduces the biodiesel temperature to approximately 26-33° C., and a third cooling stage further reduces the biodiesel temperature to at least 18-24° C.

7. The method of claim 1 wherein the filtering step includes multiple stages.

8. The method of claim 7 wherein a first filtering stage includes the addition of an adsorbent to the biodiesel.

9. The method of claim 8 whereby the adsorbent is selected from the group consisting of diatomaceous earth, silica, sand, and mixtures thereof.

10. The method of claim 9 wherein the adsorbent is diatomaceous earth.

11. The method of claim 10 wherein the diatomaceous earth is between 0.1% to 0.25% by weight of the biodiesel.

12. The method of claim 8 wherein the first filtration stage includes a leaf filter.

13. The method of claim 7 wherein a second filtration state includes a sock filter.

14. A method for improving the quality of biodiesel fuel, comprising: pretreating a supply of triglycerides to remove impurities;converting the triglycerides into methyl esters and glycerin;cooling the methyl esters to a temperature of less than about between 38° C. so as to form particles of non-methyl esters; and thenfiltering the methyl esters through at least one filter to remove the non-methyl ester particles and thereby produce improved biodiesel fuel.

15. The method of claim 14 wherein the cooling is accomplished in a series of heat exchangers.

16. The method of claim 14 wherein the filtering is accomplished through a series of filters.

17. The method of claim 14 further comprising adding an adsorbent to the methyl esters after cooling and before filtering to form a slurry.

18. The method of claim 11 wherein the adsorbent is diatomaceous earth.

19. The method of claim 11 wherein the slurry is filtered through a leaf filter to remove particles from the biodiesel.

20. The method of claim 19 wherein the biodiesel is further filtered through a sock filter to remove particles.

21. The method of claim 14 further comprising winterizing the filtered methyl esters.

22. The method of claim 21 further comprising fractionating the winterized methyl esters.

23. The method of claim 14 wherein the methyl esters meet ASTM D6751 specifications or greater before cooling.

24. An improved biodiesel production process, comprising: processing triglycerides to produce biodiesel;cooling the biodiesel with at least one heat exchanger so as to precipitate out particulates;filtering the cooled biodiesel to remove the particulates; andperiodically cleaning the heat exchanger by passing the uncooled biodiesel through the heat exchanger without supplying coolant to the heat exchanger.

25. The process of claim 24 further comprising restoring coolant flow to the heat exchanger after the cleaning step and recycling the biodiesel used for cleaning to the heat exchanger for cooling.

26. The process of claim 24 further comprising adding an adsorbent to the cooled biodiesel prior to filtration.

27. The process of claim 26 wherein the adsorbent is diatomaceous earth.

28. The process of claim 24 wherein the filtering step utilizes a pressure leaf filter.