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

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

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

Introduction Biodiesel - Advantages Biodegradable Low emission profile Low toxicity Efficiency High lubricity 99 00 01 02 03 04 05 06 4

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Metal oxides in transesterification Eappl = 91.28 KJ mol-1 Figure 4 Effect of reaction temperatures 19

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

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

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

Metal oxides in hydrolysis Oil containing 5.30 % water and 94.70 % triglycerides Figure 9 Water content changes during the process using refined oil with 5 % water addition 23

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

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

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

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

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

Acknowledgement Financial support from the Department of Energy (DE12344458) and Michigan’s 21st Century Job Fund is gratefully acknowledged.