Abstract

iii

1.

Introduction

1

1.1

Problem Statement

1

1.2

Objective

3

1.3

Work Performed

4

2.

Literature Review

7

2.1

Claus Process

7

2.2

Thermal Decomposition of H₂S without Catalyst

9

2.3

Thermal Decomposition of H₂S with Catalyst

9

2.4

Thermal Decomposition of H₂S while Products are Continually Removed

14

2.5

Oxidation of H₂S by O₂

15

2.6

Partial Oxidation of H₂S by CO₂

16

2.7

Other Miscellaneous Process

18

2.8

Summary and Choice of Methods

19

3.

Experimental System

21

3.1

Design and Construction of Experimental Systems

21

3.1.1

Experimental Apparatus for the Synthesis of Catalyst

21

3.1.2

TGA System for Sulfided Catalyst Preparation

21

3.1.3

Packed-Bed Reaction System for Catalyst Screening Studies

21

3.1.4

Apparatus for Absorption Test of Sulfur Vapor

25

3.1.5

Hybrid Reaction System – Catalytic Decomposition and Adsorption

27

3.2

Experimental Procedures

28

3.2.1

Synthesis of Catalyst

28

3.2.2

Preparation of Sulfided Catalyst

29

3.2.3

Catalyst Screening Studies in Packed-Bed Reactor

30

3.2.4

Adsorption Test of Sulfur Vapor

34

3.2.5

Decomposition of H2S with Adsorption of Sulfur

35

4.

Results and Discussion

36

4.1

Potential Catalysts and Related Experimental Materials

36

4.2

Preparation of Analytical Techniques and Instruments

37

4.2.1

TGA

37

4.2.2

Preparation and Calibration of Gas Chromatograph

37

4.3

Temperature Profile in the Quartz Reactor

38

4.4

Thermal Stability of the Co-Mo Catalyst vs. Its Specific Surface Area

39

4.5

TGA Results of Catalyst Sulfidation

40

4.6

Decomposition of H₂S under Non-Catalytic Conditions

41

4.7

Decomposition of H₂S under Catalytic Conditions

42

4.7.1

Pure H₂S Feed

42

4.7.2

H₂S – CO₂ Feed

43

4.8

Absorbability of Elemental Sulfur on Solid Adsorbents

45

4.9

Simultaneous Sulfur Adsorption and Catalytic Reaction in a Packed-Bed Reactor

46

5.

Thermodynamic Analysis and Simulation

49

5.1

Reaction System and Assumptions

49

5.2

Background of the Simulation Software and Data

49

5.3

Enthalpy and Gibbs Free Energy

50

5.4

Simulation Results

51

5.4.1

Equilibrium Distribution of H₂S and S₂

51

5.4.2

Conversion of H₂S

52

5.4.3

Yields of S₂

52

5.4.4

Selectivity of S₂

53

5.4.5

Continuous Removal of Sulfur

53

5.4.6

Possible Side Reactions

61

6.

Conclusions

62

7.

Recommendations for Future Work

63

8.

References

65

9.

List of Figures

82

10.

List of Tables

86