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Pre-Methanation Purification Study: Removal of Low Concentration Gaseous Sulfur Compounds
(Catalyst Poisons).  Final Report for the Period July 1975 - July 1977

Edward P. Loccarino
Lieberman, Martin
Taylor, William F.

Exxon Research and Engineering Company

Table of Contents

Section 1
841kb		 1 Introduction 1
2 State-of-the-Art Assessment 3
 

2.1

 Absorption Processes 3
  2.1.1 Amine Scrubbing 4
2.1.2 Benfield Hot Potassium Carbonate Process 4
2.1.3 The Linde-Lurgi Rectisol Process 6
2.1.4 IFP's Sulfur Removal Process 10
2.1.5 Holmes-Stretford Process 13
2.1.6 Claus Process 15
2.1.7 Selexol Process 17

2.2

 Trace Sulfur Compound Cleanup Processes 19
  2.2.1 Dry Box Process 20
2.2.2 The Seaboard Process 20
2.2.3 Gas Cleaning Using Caustic Soda Solution 20
2.2.4 Cyclic Use of Calcined Dolomite to Desulfurize Fuels Undergoing Gasification 21
2.2.5 Gas Sweetening Using Molecular Sieve Method 21
2.2.6 Catalytic Conversion 24
2.2.7 Zinc Oxide 26
2.2.8 Iron Oxide 26
2.2.9 Activated Carbon 27
2.2.10 Metal (CuO/Cr2O3) Impregnated Activated Carbon 28
Section 2
820kb

3

 Description of Experimental Unit 30
  3.1 Mixed Gas Compression and Feed System 32
3.2 Sulfur Compound Injection System 32
3.3 Gas/Sulfur/Water Blending Section 33
3.4 Sulfur Removal Section 33
3.5 Analytical Train 34
3.6 Unit Shakedown Experience 34

4

 Experimental Results 35
  4.1 Selection of Sulfur Compound Feed Concentrations 35
4.2 Single Component Adsorption Studies 36
  4.2.1 Hydrogen Sulfide in Nitrogen 36
4.2.2 Hydrogen Sulfide in Dry Synthesis Gas 37
4.2.3 Carbonyl Sulfide in Synthesis Gas 43
4.2.4 Thiophene in Synthesis Gas 48
4.2.5 Hydrogen Sulfide (Low Concentration) in Synthesis Gas 51
Section 3
801kb		 4.2.6 Methyl Mercaptan in Synthesis Gas 56
4.2.7 Carbon Disulfide in Synthesis Gas 60
4.3 Multicomponent Adsorption Data 61
 

4.3.1

 Four Component Sulfur Blends - Carbonyl Sulfide, Carbon Disulfide, Thiophene, Methyl Mercaptan 61

4.3.2

 Five Component System - Carbonyl Sulfide, Carbon Disulfide, Thiophene, Methyl mercaptan and Hydrogen Sulfide 69
4.4 Analysis of Reporducibility of Sulfur Compound Adsorption 75

5

 Economic and Environmental Assessment 78
  5.1 Sulfur Guard Process Costs 78
5.2 Environmental Considerations - Sorbent Disposal Options 78
5.3 Rectisol vs. Benfield Processes 79
Section 4
743kb

6

 Summary and Conclusions 80

7

 References 82
Appendix A Cost Quotation for Katalco 7-2 Activated Carbon 84
Appendix B Cost Estimates for Rectisol and Benfield Sulfur Gas Removal Processes 87
Appendix C Adsorption of Sulfur Compounds from Synthesis Gas - Theoretical Analysis 98

List of Figures

No. Page
2.1 Amine Scrubbing 5
2.2 Benfield Hot K2CO3 Process 7
2.3 2 Stage Rectisol Was for H2S and CO2- Removal 8
2.4 Claus Unit Tail Gas Cleaning with the IFP Process 11
2.5 Holmes-Stretford Process 14
2.6 Typical Claus Plant 16
2.7 Selexol Plant 18
2.8 Cyclic Use of Calcined Dolomite Sulfur Desorber and Sulfur Recovery 22
3.1 Test Unit Block Diagram 31
4.1 Removal of H2S in Pure N2 Using Metal-Impregnated Activated Carbon 39
4.2 Removal of H2S in Dry Simulated Synthesis Gas Via Metal-Impregnated Activated Carbon 42
4.3 Removal of COS in Simulated Synthesis Gas Via Metal-Impregnated Activated Carbon 46
4.4 Removal of COS in Simulated Synthesis Gas Via Metal-Impregnated Activated Carbon 47
4.5 Removal of Thiophene in Simulated Synthesis Gas Via Metal-Impregnated Activated Carbon 50
4.6 Removal of H2S in Simulated Synthesis Gas Via Metal-Impregnated Activated Carbon 54
4.7 Removal of CS2 in Simulated Synthesis Gas Via Metal-Impregnated Activated Carbon 63
4.8 Removal of COS, CS2, Thiophene, and CH3SH in Synthesis Gas Via Metal- Impregnated Activated Carbon 67
4.9 Removal of COS, CS2, Thiophene, and CH3SH in Synthesis Gas Via Metal- Impregnated Activated Carbon 68
4.10 Removal of COS, CS2, Thiophene, CH3SH, and H2S in Synthesis Gas Via Metal-Impregnated Activated Carbon 73
4.11 Removal of COS, CS2, Thiophene, CH3SH, and H2S in Synthesis Gas Via Metal-Impregnated Activated Carbon 74

List of Tables

No. Page
2.1 Stream Identification in Rectisol Process 9
2.2 Operating Parameters of IFP Process 12
4.1 Removal of H2S in Pure N2 Using Metal-Impregnated Activated Carbon 38
4.2 Removal of H2S in Dry Simulated Synthesis Gas Using Metal-Impregnated Activated Carbon 41
4.3 Removal of COS in Simulated Synthesis Gas Using Metal-Impregnated Activated Carbon 45
4.4 Removal of Thiophene in Simulated Synthesis Gas Using Metal-Impregnated Activated Carbon 49
4.5 Removal of H2S in Simulated Synthesis Gas Using Metal-Impregnated Activated Carbon 53
4.6 Removal of Methyl Mercaptan in Simulated Synthesis Gas Using Metal- Impregnated Activated Carbon 59
4.7 Removal of CS2 in Simulated Synthesis Gas Using Metal-Impregnated Activated Carbon 62
4.8 Removal of COS, CS2, Thiophene, and CH3SH in Simulated Synthesis Gas Using Metal-Impregnated Activated Carbon 65
4.9 Removal of COS, CS2, Thiophene, CH3SH, and H2S in Simulated Synthesis Gas Using Metal-Impregnated Activated Carbon 71
4.10 Trace Sulfur Compound Adsorption Data Precision Analysis 76