1. Biodiesel Production by Simultaneous Transesterification and Esterification
Present at AIChE Meeting
Nov. 20, 2008
Shuli Yan, Manhoe Kim, Steve O. Salley, John Wilson, and K. Y. Simon Ng
National Biofuels Energy Laboratory
NextEnergy/Wayne State University
Detroit, MI 48202 1

2. Outline Introduction Experiment Results and Discussion Conclusion
Biodiesel
Traditional Processes for Biodiesel Production
Literature Review
Transesterification
Esterification
Hydrolysis
Effects of FFA and Water
Effect of Catalyst Structure 2

3. Introduction Biodiesel A mixture of fatty acid esters
Derived from vegetable oils, animal fats, waste oils 3

4. Introduction Biodiesel - Advantages Biodegradable Low emission profile
Low toxicity
Efficiency
High lubricity 4

5. Introduction Traditional Processes for Biodiesel Production
Refined oils as feedstock (food-grade vegetable oils)
Homogeneous strong base or acid catalysts (NaOH, H2SO4)
FFA content is lower than 0.5 % (wt)
Water content is lower than 0.06% (wt)
High price
Large amount of waste water
Long time for phase separation
High process cost
Highly corrosive
Long oil pretreatment process
Long product purification process 5

6. Introduction Decrease of Feedstock Cost Decrease of Process Cost
Using unrefined or waste oils as feedstock
Crude vegetable oils, recycled cooking oils, trap grease etc.
Simplifying the pretreatment and reaction process
Simultaneous catalysis of transesterification and esterification
Simplifying the product purification process
Replace homogeneous catalysts by heterogeneous catalysts 6

7. Figure 1 Effects of FFA and water on traditional processes
Introduction
Effects of FFA and water
Decrease
Decrease
Figure 1 Effects of FFA and water on traditional processes

8. Literatures ZnO La2O3 Mixed ZnO- La2O3 System ZnO, ZnO-Al2O3, I2/ZnO
Contain base or acid sites
Low activity and unstable, low tolerance to water and FFA
La2O3
La2O3/TiO2, La2O3-Ni/MgO
Structure promoter, increase surface base site, thermal stability
No reports in biodiesel production
Mixed ZnO- La2O3 System
Homogeneous Co-precipitation
Zn:La = 1:0 1:1 3:1 9:1 0:1 8

9. Unrefined or waste oils
Transesterification Esterification Hydrolysis
Figure 1 Reactions involved in the treatment of crude oils using Zn3La1 catalyst. 9

10. Objective Develop a new class of heterogeneous catalysts
High tolerance to water and FFA
Simultaneously catalyze transesterification and esterification, while minimizing hydrolysis
Process crude oils directly
Our research goal is: …… 10

11. Experiment Homogeneous Co-precipitation Method
Prepare mixture solutions of Zn(NO3)2 , La(NO3)3 and urea in appropriate ratios
Heat to 100 oC and hold for 6 hr
Stirred with magnetic stirrer
Filter/unfilter
Dry at 150 oC for 8 hr
Use step-rise calcination method to control the catalyst morphology 11

12. Experiment Reactor Product analysis Parr 4575 HT/HP Reactor
(500 ml, 500 C, 34 MP)
Transesterification
Esterification
Hydrolysis
GC-MS
Karl Fischer (Water Content)
Titration (Fatty Acid Content) 12

13. Catalyst characterization
XRD
ZnO, La2CO5 LaOOH
XRD
Figure 13 XRD patterns of zinc and lanthanum mixed metal oxides 13

14. Catalyst Characterization
Table 1 XRD Structures of Zinc and Lanthanum Mixtures
Catalyst
XRD structure
Mean grain size of ZnO nm
Lattice constants for ZnO phase
Zn : La (bulk molar ratio )
a Å
c Å
Vol Å3
Density
Zn10La0
ZnO
>100
3.25
5.21
47.63
5.68
1:0
Zn9La1
27.6
5.36
48.62
5.56
8.9: 1
Zn3La1
ZnO, La2CO5 LaOOH
17.1
5.23
47.81
5.65
3.5: 1
Zn1La1
9.8
3.33
5.10
49.12
5.50
1.2: 1
Zn0La10
La2CO5 LaOOH /
0:1 14

15. Table 2 XPS data of Zinc and Lanthanum Mixtures
Lewis Base Site
Lewis Acid Site
Total Basic and Acid Site 15

16. Metal oxides in transesterification
Mixed oxide shows the highest activity
170 oC
Figure 1 Transesterification activities of Zn10La0, Zn3La1 and Zn0La10 as a function of temperature. 16

17. Metal oxides in transesterification
Figure 2. Transesterification activities of Zn10La0, Zn9La1, Zn3La1, Zn1La1 and Zn0La10 at 200 oC 17

18. Metal oxides in transesterification
Figure 3 Effect of initial oil concentration on transesterification. 18

19. Metal oxides in transesterification
Eappl = KJ mol-1
Figure 4 Effect of reaction temperatures 19

20. Metal oxides in esterification
140 oC
Figure 6 Esterification of oleic acid with methanol as a function of reaction temperature 20

21. Metal oxides in esterification
5 % oleic acid
in soybean oil
Pure oleic acid
Figure 7 Yield of oleic methyl ester at 200 oC
Figure 8 Process using refined oil with 5 % FFA addition 21

22. Metal oxides in hydrolysis
220 oC
Figure 8 Hydrolysis activities of Zn3La1 as a function of temperature. 22

23. Metal oxides in hydrolysis
Oil containing 5.30 % water and % triglycerides
Figure 9 Water content changes during the process using refined oil with 5 % water addition 23

24. Effect of FFA on biodiesel production
Decrease
Figure 10 Effect of FFA additions on transesterification. a: Yield of FAME in the presence of different FFA addition; b: Effect of FFA content on equilibrium yield of FAME; 24

25. Effect of water on biodiesel production
Decrease
Figure 10 Effect of water addition on transesterification. a: Yield of FAME in the presence of different water addition; b: Effect of water addition on equilibrium yield of FAME; 25

26. Using unrefined and waste oils
180 min
Figure 11 Using some unrefined or waste oils for biodiesel production 26

27. the catalyst reused 17 times
Catalyst Life
In Batch Reactor
In Continuous Reactor
the catalyst reused 17 times
the catalyst runs 32.5 days
Figure 4 Yield of FAME vs Reaction Times
Figure 5 Yield of FAME vs Reaction Times

28. Conclusion
A single-step method using unrefined oils and heterogeneous zinc and lanthanum mixed oxides
Oil transesterification reaction and FFA esterification reaction
Minimizing hydrolysis of oil and hydrolysis of biodiesel
A temperature window, 170 ~220 oC
A strong interaction between Zn and La species
La acts as a diluent of the matrix, promoting ZnO particle distribution, increasing the surface basic and acid sites, and enhancing activity of transesterification and esterification 28

29. Acknowledgement
Financial support from the Department of Energy (DE ) and Michigan’s 21st Century Job Fund is gratefully acknowledged.