Presentation is loading. Please wait.

Presentation is loading. Please wait.

Sterol Glucosides in Biodiesel

Similar presentations

Presentation on theme: "Sterol Glucosides in Biodiesel"— Presentation transcript:

1 Sterol Glucosides in Biodiesel
Haiying Tang, Steven O. Salley, and K. Y. Simon Ng National Biofuels Energy Laboratory NextEnergy/Wayne State University Detroit, MI 48202

2 Outline Chemical structure and physical properties of sterol glucosides Precipitates formation above cloud point in Soy-, Cottonseed-, and Poultry Fat-based Biodiesel Blends “Filter-Blocking Tendency ” test and cold soak filtration Analysis method Typical processing technique for oil refining Possible techniques to remove sterol glucosides Conclusion

3 Plants Sterols Free sterols Sterol esters Sterol glucosides
Acylated sterol glucosides

4 Sterol composition in seed oil (mg/kg)
Palm Soy bean Rapeseed Cottonseed Corn oil Safflower Sunflower β-sitosterol 1894 1908 3549 3961 7722 1809 2352 campesterol 358 720 1530 170 2691 452 313 stigmasterol 204 42 702 Δ5-avenasterol 51 108 122 85 468 35 156 Δ7-stigmastenol 25 306 - 117 696 588 other 26 36 612 173 195 Net % in oil 0.26% 0.36% 0.61% 0.43% 1.18% 0.35% 0.39% Data From Gunston ed al, The lipid handbook, 1994

5 Chemical Structure of Sterols
Phytosterols mainly include campesterol, β-sitosterol, stigmasterol, Δ5-avenasterol, Δ7-stigmastenol, and brassicasterol.

6 What is Sterol Glucoside in Biodiesel?
Sterol Glycosides occurs naturally in vegetable oils, mainly as soluble fatty acid esters ; Usually, the acyl sterol glycosides at concentrations are two to ten fold greater than those of the non-acylated forms; Hydrolyzed during transesterification process and become insoluble. β-sitosterol glucoside is the most typical sterol glucoside. : β-sitosterol glucosides

7 Biodiesel Reaction- Base Transesterification
100 lbs of oil +10 lbs methanol lbs of biodiesel +10 lbs of glycerol


9 Physical Properties of Free Sterol Glucosides
Powdery solid, melting point °C Limited solubility in most organic solvents except pyridine, chloroform/methanol (2:1) Soluble in fresh biodiesel.

10 Typical Concentration of SG in Biodiesel (ppm)
Feedstock SG 1 SG 2 β-sitosterol Total sterol Soy #1 Crude Grade 272 78 1908 3600 Soy #2 Degummed Grade 54 Soy #3 Refined Grade 190 Soy #4 (processed poorly) 25 Cottonseed oil #1 22 10 3961 4258 Cottonseed oil #2 8 Corn oil 480 45 7722 11700 Palm oil 141 118 1894 2558 Safflower Crude Grade 14 1809 3478 Sunflower 18 2352 3917 Canola Data from 1 Ringwald SC. Biodiesel characterization in the QC environment; 2 Pfalzgraf et al , Identification of sterol glucosides in biodiesel and their effect on filterability.

11 Precipitates Formation above Cloud Point in Soy-, Cottonseed-, and Poultry Fat-based Biodiesel Blends

12 Cold Flow Properties: a current issue with biodiesel
Precipitates formation in biodiesel blends may have serious implications. Clogging of fuel filters. Formation of deposits on engine parts such as injectors and other critical fuel system components.

13 ASTM Test Methods Cold–flow properties: traditional petroleum wax precipitation Cloud point (CP, ASTM 2500): at which crystallization begins. Pour point (PP, ASTM 97): at which the fuel no longer will pour. Cold filter plugging point (CFPP, ASTM 6371): at which fuel starts to plug a fuel filter. Total insoluble: high temperature in the presence of oxygen ASTM D 2274 (Accelerated Method): Oxidation Stability of Distillate Fuel (95 ºC for 16 h). ASTM D 4625: Storage Stability of Middle Distillate, Petroleum (43 ºC for selected periods up to 24 weeks).

14 Filtration system from ASTM D4625-04
Experimental Samples: SBO-, CSO-, and PF- based biodiesel ULSD, B2, B5, B10, B20, B50, B70, and B100 300 mL volume Storage Temperature and Time -15 ºC for 24 hr 4 ºC for 24 hr 23 ºC for 24 hr (Control) Allow to come to room temperature without external heating Filter Vacuum pump: ~68 kpa 0.7 mm glass fiber filter Filtration system from ASTM D

15 Physical Appearance (at 23 ºC for 24 hours )
SBO-based Biodiesel ULSD B2 B5 B10 B20 B50 B70 B100

16 Physical Appearance (at 4 ºC for 24 hours)
SBO-based Biodiesel ULSD ULSD ULSD B2 B10 B5 B20 B50 B70 B100

17 Physical Appearance (at -15ºC for 24 hours)
B10 ULSD B2 B5 B20 B50 B70 B100

18 Optical Images of Precipitates
50X 200X Taken from B20 SBO-based biodiesel

19 Time to Filter Vs. Temperature
SBO-based biodiesel

20 Insolubles Mass Vs. Temperature
No significant mass of “new” insolubles as result of blending at 23 ºC ; Significant effect at 4 ºC; Above the cloud point insolubles are very different in nature as compared to the normal wax-crystal like insolubles formed below cloud point.

21 Insolubles Mass Vs. Time
Different mechanisms for the insolubles formation from B20 and B100; For B20, the relatively fast appearance of insolubles can be attributed to a solvency effect. B100 B20

22 Insolubles Mass Vs. Feedstock
CSO- and PF- based biodiesel had lower insolubles levels than the SBO-based biodiesel; The difference may be attributed to the presence of naturally occurring levels of sterol glucosides in the feedstocks.

23 Cloud Point, Pour Point, and Cold Filter Plugging Point
The CFPP may indicate relative extent of the insolubles formation at low temperature.

24 Nature of Insolubles Possibilities
Sterol glucosides: Soluble within vegetable oil; however, hydrolyzed during transesterification process and become insoluble. Monoglycerides, diglycerides, triglycerides of total glycerin; Dimers, trimers, tetramers of oxidative products; Solvency effect when blended with ULSD.

25 Distilled and Oxidized Biodiesel
After cold soak test, no insoluble was observed in distilled or oxidized B100, or even in B20; Insolubles formation is due to minor component; Insolubles formation is not due to oxidized product. The nature of “the above cloud point insolubles” formation is different from the oxidized insolubles observed in the high temperature stability test of biodiesel; Distillated SBO-B20 Oxidative Biodiesel Blends

26 Nature of Insolubles: FTIR Spectra
-CH2 -CH2 -OH C-O-C Insolubles from SBO-B100 Insolubles from SBO-B20 Insolubles fromCSO-B100 Insolubles from CSO-B50 Standard Sterol Glucosides

27 Nature of Insolubles: GC-FID Chromatograms
Insolubles from CSO-B100 Insolubles from SBO-B100 Internal Standard Standard Sterol Glucosides Three kinds of Sterol Glucosides

28 GC-FID Chromatogram (Continued)
Precipitates from PF-B100 Standard Glycerides

29 Summary 1 Storage temperature, storage time, biodiesel blend level, and feedstock affect the mass of insolubles formed; Solvency of ULSD has a significant influence on insolubles formation; Insolubles from SBO- and CSO-based biodiesel are due to sterol glucosides. However, the insolubles from PF-based biodiesel can be attributed to glycerides.

30 “Filter-Blocking Tendency ”Test
Tests 300ml of fuel at 20ml/min Filter ASTM D2068/IP387 1.6 micron Result calculated based on pressure and volume measured during the test.

31 Filter-blocking tendency (FBT)
Effect of SG on FBT SG content (ppm) Filter-blocking tendency (FBT) 22 (Control) 1.05 (pass) 32 1.47 (fail) 52 2.90 (fail) 72 15.03(fail) Adding SG to biodiesel caused it to fail to the FBT test; SG presence at high enough levels could potentially cause filter problems. Data from Lee et al. The role of sterol glucoside on filter plugging, Biodiesel Magazine 2007.

32 Biodiesel Cold Soak Filtration
Storage temperature and time 4 ºC (refrigerator) 16 hours Allow sample to come to the room temperature (23 ºC to 24 ºC ) Filter Vacuum pump: 22.5 inches Hg (~76.2 Kpa) Whatman 47 mm GF/F, 0.7 mm.


34 Biodiesel Cold Soak Filtration

35 Different Feedstocks of Biodiesel
1 2 3 4 5 6 7 Feedstock Canola Soy Animal Fat ImprSoy Dist Soy Palm

36 Analysis of Sterol Glucosides
The presence of sterol glucosides in biodiesel residues has been confirmed using FTIR and GC-FID Qualification will be evaluated by GC- FID, HPLC, and FTIR with purchased known standards

37 Preliminary results :GC-FID Chromatograms
sitosterol glucoside stigmasterol glucoside campesterol glucoside Precipitates from REG Precipitates from Nextdiesel Standard sterol glucosides

38 Process of Crude Soybean Oil to Food-grade Oil
Chemical refining Water degumming Chemical neutralization Bleaching Deodorization Physical refining Acid degumming Refining Water degumming Caustic refining Bleaching Deodorization

39 Conventional RBD Process Phospholipids and gums
Phosphoric acid NaOH Bleaching clays Steam vacuum CRUDE OIL CHEMICAL NEUTRALIZATION BLEACHING DEODORIZATION (Distillation) WATER DEGUMMING REFINED OIL Phospholipids and gums Free fatty acids Pigments Trace component Reduce portion of free sterols Reduce portion of free sterols Remove portion of SG

40 Average Composition for Crude and Refined Soybean oil
Data from Van Gerpen, J.; Biodiesel production technology, 2004

41 Process techniques to remove SG
Filtering:  removal of particulate from media with a steel screen, cartridge or filter paper Effect of filter pore sizes Effect of filter types Cold filtering: holding the biodiesel at a lower temperature for desired time before the filtering process.  Effects of cold filter temperature Effect of storage time Particle

42 Preliminary Results: Effect of temperature on removing particles with filtration
ppm 23 ºC 4 ºC -15 ºC ULSD 0.9 1.43 B2 1.23 1.67 2.57 B5 3.9 4.23 B10 6.67 B20 1.57 7.77 4.57 B50 2.23 14 22.33 B70 3.33 19.23 20.77 B100 5.77 9.1 32.23 1.43 2.57 4.23 6.67 4.57 22.33 20.77 32.23 Cold filtration is better to remove particles than room temperature filtration

43 Preliminary Results: Effect of storage time on removing particles with cold filtration (4 ºC )
ppm B100 B20 5.67 1.67 1 hr - 3 2 hr 3.33 4.83 4 hr 5.83 8 hr 5 7.33 20 hr 13.67 7.17 24 hr 11.67 8.5 3 days 30 9.33 1 weeks 40 14.33 2 weeks 43 25.17 Longer storage time in cold soak test could more effective to remove particles in biodiesel. 1.67 3 4.83 5.83 6.83 7.33 7.17 8.5 9.33 14.33 25.17

44 Process techniques to remove SG (Con.)
Adsorbent treatment: Removal of particulate with a porous pad or a “cake” of filter-aid-type materials Diatomaceous earth (DE) Magnesol Carbon Magnesium silicate Act as deep filtration Effect of concentration Effect of incubation time Effect of temperature Mix Tank Filter Finished product tank Untreated Biodiesel Adsorbent

45 SG content of biodiesel after incubation and filtering through DE
Incubation temperature (ºC) Incubation time SG content (ppm) (FBT) 54 15.03 (fail) 4 6 hr 22 1.2 (pass) 12 hr 25 - 10 27 21 1 day 19 2 days 16.29 3 days 17.29 Data from Lee et al. Processes of producing biodiesel and biodiesel produced therefrom; Patent application publication, 2007.

46 Process techniques to remove SG (Con.)
Water degumming: a basic process to wash biodiesel product to remove contaminants Effect of water ratio Effect of mixing temperature Vacuum distillation: an energy intensive technique for biodiesel processing Effect of temperature Effect of pressure

47 Preliminary Result: GC-FID Chromatography
Sterol glucosides SBO-biodiesel Glycerol Precipitates from SBO-biodiesel Distillated SBO-biodiesel

48 Conclusions

49 Future Work Evaluate and develop processing strategies to reduce sterol glucosides content in biodiesel; Develop a robust analytical method to determine the sterol glucosides content in biodiesel. In the next steps, we will

50 Thanks! Questions?

Download ppt "Sterol Glucosides in Biodiesel"

Similar presentations

Ads by Google