Biodiesel production from oils containing high content of water and FFA using zinc lanthanum mixture oxides as catalyst Shuli Yan 2008-02-18

Biodiesel production from oils containing high content of water and FFA using zinc lanthanum mixture oxides as catalyst

Shuli Yan

2008-02-18

Outline

• Introduction

• Experiments

• Results and Discussion

•Biodiesel

•Oils used in traditional processes for biodiesel production

•Homogeneous catalysts for biodiesel production

•Catalytic activity of Zn and La mixture oxides

•Effect of FFA addition on transesterfication

•Effect of water addition on transesterfication

•Catalyst structure and their effects on biodiesel production

Introduction

• Biodiesel

Biodegradable

Low emission profile

Low toxicity

Better fuel

Efficiency

High lubricity

Oils used in traditional processes for biodiesel production

Food grade vegetable oils( soybean oil $2.03/gal, $0.27/lb)

FFA content is lower than 0.5 % (wt)

Water content is lower than 0.06% (wt)

Introduction

Crude oils and yellow grease( about 50 % of food oil)

FFA content is in the range of 0.5 ~ 15 % (wt)

Water content is higher than 0.06% (wt)

Therefore:

Introduction

Prices of some inexpensive materials ( Rudeck, 2000 )

Bulk Price range (per pound) Average price

Animal/livestock feed $0.09–$0.14 $0.12

Tallow $0.10–$0.20 $0.17

Grease $0.07–$0.20 $0.16

Introduction

• Negative effects of FFA and water in homogeneous catalysis for biodiesel production

Saponification of FFA with alkaline catalysts

Hydrolysis of triglyceride

Introduction

Difficulties in phase separation

A lot of washing water

Environmental unfriendly

Therefore:

Developing a heterogeneous catalyst

Homogeneous catalysts for biodiesel production

Simultaneous transesterification and esterification

Minimizing hydorlysis and saponification

Developing a heterogeneous catalyst with high activity

Processing feedstocks with high content of FFA and water

Our goal

Experiments

Catalyst preparation and characterization

Homogeneous-coprecipitation method using urea as precipitant

1. Prepare a mixture solution of Zn(NO3)2 , La(NO3)3 and urea

2. Heat to 100 oC and hold for 6 hr

3. Stirred with magnetic stirrer

4. Filter/unfilter

5. Dry at 150 oC for 8 hr

6. Use step-rise calcination method at 250 (2hr), 300 (2hr), 350 (2hr), 400 (2hr), 450 oC (8hr),

SEM/EDS, XRD, XPS, FT-IR

Zn:La

1:0 1:1 3:1 9:1 0:1

Pure ZnO, Zn1La1, Zn3La1, Zn9La1, Pure La2O3

Experiments

• Transesterification

Molar ratio of methanol to soybean oil-----------------42:1

Catalyst dosage--------------------2.3 %(wt)

Stir speed----------------------------490 rpm

Experiments

• FAME yield

• Water content

• FFA content

Clarus 500 GC-MS, Perkin-Erlmer

831 KF Coulometer

809 KF Coulometer

Results and discussion

• Catalytic activity of zinc lanthanum metal oxides for transesterification

Figure 1 Catalytic activity of metal oxides at different reaction temperatures

160 180 200 220 2400

5

10

15

20

25

30

35

40

45

Yie

ld o

f FA

ME

%

Temperature oC

Zn3La1

Pure La2O

3

Pure ZnO

Blank

Reaction conditions: molar ratio of methanol to oil is 42:1, catalyst dosage is 2.3 (wt)%, stir speed is 490 rpm;using step-rising heat method to control the reaction temperature; heating speed is 2 oC/min, and hold at the target temperature for 1 min.


Figure 2 Transesterification results of Zn3La1 at different temperatures

Reaction conditions: molar ratio of methanol to oil is 42:1, catalyst dosage is 2.3 (wt)%, stir speed is 490 rpm;

0 100 200 300 4000

20

40

60

80

100

200 oC

Time min

Yie

ld o

f FA

ME

%

210 oC

180 oC

190 oC


Figure 3 Effect of catalyst composition on transesterification

Reaction conditions: molar ratio of methanol to oil is 42:1, catalyst dosage is 2.3 (wt)%, reaction temperature is 200 oC stir speed is 490 rpm;0 100 200 300 400

0

20

40

60

80

100

Pure La2O

3

Time min

Pure ZnO

Yie

ld o

f FA

ME

%

Zn1La1

Zn3La1

Zn9La1


• Effect of FFA addition on transesterification

Figure 4 Yield of FAME in the presence of different FFA addition

Reaction conditions: molar ratio of methanol to oil is 42:1, catalyst dosage is 2.3 (wt)%, reaction temperature is 200 oC, stir speed is 490 rpm;

0 10 20 30 40 50 60 70 80 90 1000

20

40

60

80

100

10 %

Time min

FFA addition

15 %

Yie

ld o

f FA

ME

% 30 %

5 %

0 %

FFA content in refined oil: 0.02 %


0

20

40

60

80

100

0 10 20 30

Acid catalystYie

ld o

f FA

ME

%

Zn3La1

FFA content %

Alkaline catalyst

Figure 5 Effect of FFA content on equilibrium yield of FAME of the transesterification processes

Reaction conditions:1. Acidic catalysis process, sulfuric acid amount is 3 %, molar ratio of methanol to oil is 6:1, reaction temperature is 60 oC, and reaction time is 96 hr. 2. Alkaline catalysis process, KOH amount is 1 %, molar ratio of methanol to oil is 6:1, reaction temperature is 25 oC, and reaction time is 8 hr. 3. Heterogeneously catalytic process, catalyst amount is 2.3 (wt)%, molar ratio of methanol to oil is 42:1, reaction temperature is 200 oC, and reaction time is 1.5 hr.


• Effect of water addition on transesterification

0 20 40 60 80 100 120 140 160 1800

20

40

60

80

100

1 %

Yie

ld o

f FA

ME

%

Time min

Water addition

5 %

0 %

3 %

Figure 6 Yield of FAME in the presence of different water addition

Reaction conditions:

catalyst amount is 2.3 (wt)%, molar ratio of methanol to oil is 42:1, reaction temperature is 200 oC, stir speed is 490 rpm;

Water content in refined oil is 0.0229 %, in methanol is 0.0191 %.


0 1 2 3 4 50

20

40

60

80

100

Alkaline catalyst

Yie

ld o

f FA

ME

%

Water content %

Zn3La1

Acid catalyst

Figure 7 Effect of water content on equilibrium yield of FAME of the transesterification processes

Reaction conditions:1. Acidic catalysis process, sulfuric acid amount is 3 %, molar ratio of methanol to oil is 6:1, reaction temperature is 60 oC, and reaction time is 96 hr. 2. Alkaline catalysis process, KOH amount is 1 %, molar ratio of methanol to oil is 6:1, reaction temperature is 25 oC, and reaction time is 8 hr. 3. Heterogeneously catalytic process, catalyst amount is 2.3 (wt)%, molar ratio of methanol to oil is 42:1, reaction temperature is 200 oC, and reaction time is 145 min.


• Using oils containing high content of water and FFA in transesterification for biodiesel production

0

20

40

60

80

100

0 20 40 60 80 100 120 140 160 180 200

Refined soybean oil with 3 % water addition and 5 % FFA additionY

ield

of F

AM

E

%

Crude soybean oil

Time min

Refined soybean oil

Figure 8 Using oils containing high content of water and FFA for biodiesel production

Reaction conditions:catalyst amount is 2.3 (wt)%, molar ratio of methanol to oil is 42:1, reaction temperature is 200 oC, stir speed is 490 rpm;


• Effect of catalyst structure on transeseterification

XRD, SEM/EDS, XPS, FT-IR

a. High specific surface area, multiporous structure, uniform bulk phase structure.

b. Both acidic and basic sites exist on the surface of catalyst, and they participate in the formation of FAME.

c. Active centre for transesterification (Effect of basic sites on transesterification)

d. Active centre for esterification (Effect of acidic sites on esterfication)

e. Catalytic ability of zinc lanthanum mixture oxides to hydrolysis reaction when oils containing high content of water


• SEM/EDS


• FFA Esterification in the presence of oil

0 20 40 60 80 100

2

4

6

8

10

12

TA

N

mgK

OH

/g

Time min

Figure 9 TAN changes during the process using refined oil with 5 % FFA addition


catalyst amount is 2.3 (wt)%, molar ratio of methanol to oil is 42:1, reaction temperature is 200 oC, stir speed is 490 rpm, FFA addition is about 5 %;


Figure 10 water content changes during the processes using refined oil with 5 % water addition and without water addition

0 20 40 60 80 100 120 140 1600

1

2

3

4

5

6

0 20 40 60 80 100 120 140 1600

1

2

3

4

5

6

Wa

ter

con

ten

t %

Time min

Refined oil with 5 % water addition

Refined oil


catalyst amount is 2.3 (wt)%, molar ratio of methanol to oil is 42:1, reaction temperature is 200 oC, stir speed is 490 rpm, water content in oil is about 5.2 (wt)%catalyst amount is 2.3 (wt)%, molar ratio of methanol to oil is 42:1, reaction temperature is 200 oC, stir speed is 490 rpm, water content in oil is about 0.9 (wt)%


• Reaction pathway for FAME formation when using oils with a high content of FFA and water

Crude Oils

Transesterification Hydrolysis Esterification Hydrolysis

Triglyceride Water FFA

Fatty acid methyl esters

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Biodiesel production from oils containing high content of water and FFA using zinc lanthanum mixture oxides as catalyst Shuli Yan 2008-02-18