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CO Hydrogenation Over Cobalt Fischer-Tropsch Catalysts - 1993

Hoff, A.

Norges Tekniske Hoegskole

Table of Contents

 

Abstract

Acknowledgements

List of Symbols and Abbreviations

List of Figures and Tables

Section 1
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1

Introduction

1
 

1.1

The Fischer-Tropsch synthesis history

1

1.2

Fischer-Tropsch synthesis today

2

1.3

Objectives of the present work

4

1.4

SPUNG

5

2

Literature Review

7
 

2.1

Fischer-Tropsch reaction mechanism

7

2.2

Kinetics

12

2.3

Cobalt catalysis

16

2.4

Characteristics of the Co/Al2O3 system

17
 

2.4.1

Cobalt spinals

18

2.4.2

Effect of cobalt loading

19

2.4.3

Effect of Calcination temperature

22

2.4.4

Effect of cobalt precursor

23

2.4.5

Promotion with noble metals

24

2.5

Activity and selectivity

30
 

2.5.1

Reduction extent and dispersion

30

2.5.2

CO hydrogenation activity

32

2.5.3

CO hydrogenation selectivity

34

2.5.4

Activity and selectivity of bimetallic systems, compared to monometallic systems

37

Section 2
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3

Experimental

43
 

3.1

Catalysts preparation

43

3.2

Temperature programmed reduction

46
 

3.2.1

Principles

46

3.2.2

Apparatus and procedure

47

3.3

Pulse O2 titration

49
 

3.3.1

Principles

49

3.3.2

Apparatus and procedure

49

3.4

Volumetric Chemisorption of H2 and CO

50
 

3.4.1

Principles

50

3.4.2

Apparatus and procedure

51

3.5

Kinetic Investigations

53
 

3.5.1

Apparatus and analytical equipment

53

3.5.2

Procedure for kinetic experiments

53

4

Results and Discussion

57
 

4.1

Characterization of catalysts

57
 

4.1.1

Temperature programmed reduction

57
 

4.1.1.1

Influence of Calcination temperature

57

4.1.1.2

Co2O4

64

4.1.1.3

Platinum promotion

67

4.1.1.4

Promotion with other noble metals

70

4.1.1.5

Reduction at standard conditions

76

4.1.1.6

Effect of chloride containing metal precursors

77

4.1.1.7

Summary of the TPR results

81

Section 3
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4.1.2

Extent of reduction determined by pulse O2-tritration

84

4.1.3

Volumetric chemisorption of H2 and CO

88
 

4.1.3.1

Effect of calcination temperature

88

4.1.3.2

Effect of platinum and rhenium promotion

90

4.1.3.3

Effect of chloride

99

4.1.3.4

Dispersion and crystallite size

102

4.1.3.5

Summary of the H2 and CO adsorption measurements

109

4.2

Activity measurements

110
 

4.2.1

High temperature / 7 bara total pressure

110

Section 4
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4.2.2

Low temperature / 1 bara total pressure

122

4.2.3

Summary of the activity measurements

130

4.3

Selectivity measurements

131
 

4.3.1

High temperature / 7 bara total pressure

131

4.3.2

Low temperature / 1 bara total pressure

141

5

Conclusions

145
 

5.1

Reduction behavior

145

5.2

H2 and CO chemisorption

146

5.3

Activity and Selectivity

147

6

References

149

Section 5
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Appendixes

157

1

Metal loading in catalysts investigated

159

2

Gases used in different apparatus

163

3

Example of an adsorption isotherm and the calculation of dispersion from chemisorption of H2 on Co/Al2O3B

165

4

Volumetric chemisorption of H2 and CO, and dispersion calculated thereof

169

5

BET surface and pore size distribution

173

6

Formulas for calculation of activity and selectivity

181

7

Product selectivity over the catalysts investigated

185