444 Castro Street, Suite 720 SFA Pacific, Inc. Mountain View, California 94041 Telephone: (650) 969-8876 Engineering & Economic Consultants Fax: (650) 969-1317 Email: [email protected] Website: www.sfapacific.com PROCESS SCREENING ANALYSIS OF ALTERNATIVE GAS TREATING AND SULFUR REMOVAL FOR GASIFICATION Revised Final Report December 2002 Prepared by Nick Korens Dale R. Simbeck Donald J. Wilhelm SFA Pacific, Inc. Mountain View, California Prepared for U.S. Department of Energy National Energy Technology Laboratory Pittsburgh, Pennsylvania NETL Project Manager James R. Longanbach DOE Gasification Technologies Product Manager Gary J. Stiegel Task Order No. 739656-00100 Task 2 SFA Pacific, Inc. ii SFA Pacific, Inc. Table of Contents PAGE NO. 1. SUMMARY.................................................................................................................. 1-1 Mercury Removal ......................................................................................................... 1-1 Acid Gas Removal ........................................................................................................ 1-2 Sulfur Recovery ............................................................................................................ 1-3 Tail Gas Treating .......................................................................................................... 1-3 Hot and Warm Gas Cleanup ......................................................................................... 1-3 Acid Gas Injection ........................................................................................................ 1-5 CO2 Removal for Sequestration.................................................................................... 1-5 2. INTRODUCTION........................................................................................................ 2-1 Background................................................................................................................... 2-1 Report Objective ........................................................................................................... 2-1 Approach to the Task.................................................................................................... 2-2 3. EMISSIONS REGULATIONS .................................................................................. 3-1 Cleanup Process Implications....................................................................................... 3-2 Sulfur Removal ....................................................................................................... 3-2 Mercury Removal ................................................................................................... 3-2 4. IGCC GAS PROCESSING OPTIONS.................................................................... 4-1 Current IGCC Gas Processing ...................................................................................... 4-1 Syngas Characteristics and Gas Cleaning............................................................... 4-1 AGR Processes Employed Commercially with Gasification.................................. 4-3 Future IGCC Processes................................................................................................. 4-5 5. MERCURY REMOVAL ............................................................................................. 5-1 Low Temperature Separation........................................................................................ 5-1 Activated Carbon .......................................................................................................... 5-2 Activated Carbon Bed Design Principles ............................................................... 5-2 Metal Carbonyls................................................................................................ 5-4 Zeolites.......................................................................................................................... 5-4 Other Methods .............................................................................................................. 5-7 6. ACID GAS REMOVAL PROCESSES.................................................................... 6-1 Amine Processes ........................................................................................................... 6-2 Flowsheet and Process Design................................................................................ 6-2 Performance and Cost Factors .......................................................................... 6-3 Generic Amine Processes ................................................................................. 6-5 iii SFA Pacific, Inc. Table of Contents (continued) PAGE NO. 6. ACID GAS REMOVAL PROCESSES (continued) MDEA..................................................................................................................... 6-5 H2S/CO2 Selectivity.......................................................................................... 6-5 COS Removal ................................................................................................... 6-6 CO2 Removal .................................................................................................... 6-7 Degradation of MDEA and Its Corrosivity....................................................... 6-8 Hindered Amines .................................................................................................... 6-9 Physical Solvents .......................................................................................................... 6-10 Selexol .................................................................................................................... 6-11 Rectisol ................................................................................................................... 6-15 Mixed Amine/Physical Solvent Processes.................................................................... 6-18 Sulfinol.................................................................................................................... 6-18 FLEXSORB PS and Hybrid FLEXSORB SE ........................................................ 6-19 General Perceptions of AGR Process Suitability for IGCC ......................................... 6-19 AGR Process Selection................................................................................................. 6-20 7. SULFUR RECOVERY PROCESSES..................................................................... 7-1 The Claus Process......................................................................................................... 7-1 Claus Plant Sulfur Recovery Efficiency ................................................................. 7-2 Oxygen-Blown Claus.................................................................................................... 7-4 The COPE Process.................................................................................................. 7-5 The OxyClaus Process ............................................................................................ 7-5 The SURE Process.................................................................................................. 7-8 Other Oxygen-Blown Claus Process Services........................................................ 7-10 Extended Bed Claus Processes ..................................................................................... 7-10 The SuperClaus Process.......................................................................................... 7-10 Extended Cold-Bed Claus Process ......................................................................... 7-11 Other Sulfur Recovery Processes ................................................................................. 7-12 The Selectox Process .............................................................................................. 7-13 Wet Oxidation (Redox) Processes—LO-CAT and SulFerox ................................. 7-13 8. TAIL GAS TREATING .............................................................................................. 8-1 Reduction of Sulfur Compounds via Hydrogenation and Hydrolysis .......................... 8-1 Tail Gas Hydrogenation/Hydrolysis ....................................................................... 8-2 Raw Synthesis Gas Hydrolysis ............................................................................... 8-2 The SCOT Process........................................................................................................ 8-3 iv SFA Pacific, Inc. Table of Contents (continued) PAGE NO. 9. HOT AND WARM GAS CLEANUP ........................................................................ 9-1 Drivers for HGCU......................................................................................................... 9-1 Waning Interest in HGCU ............................................................................................ 9-2 Further Temperature Considerations ............................................................................ 9-3 Mercury Removal ................................................................................................... 9-3 “Hot Gas” or “Warm Gas” Cleanup?...................................................................... 9-3 GT Fuel Control Valves.......................................................................................... 9-3 Syngas Conversion to Synthetic Fuels.................................................................... 9-4 Particulates