Successful Sulfur Control & Hydrogen Purification at Saras World-Scale IGCC Plant

Transcription

1 Successful Sulfur Control & Hydrogen Purification at Saras World-Scale IGCC Plant Enrico Maffeis, Claudio Allevi & Ivo Cicerelli Saras S.p.A. Bart Beuckels, Elena Truffa & Mike Whysall, A Honeywell Company GTC Conference October 28 th - 31 st, 2012 Washington, DC, USA 2012 LLC. All rights reserved.

2 s Capabilities Gasification Complexes Steam & Power Polysep Membrane CO Shift Polybed PSA Synthesis Processes Hydrogen Chemicals Synthesis Gas Raw Syngas COS Hydrolysis Selexol Process MTO Process Methanol Olefins Sulfur Recovery Methanation Sulfur Technology Partners Other Licensors FT Synthesis Liquids Upgrading SNG Liquid Fuels

3 Saras IGCC Plant Introduction Saras IGCC Plant Refinery Residues converted to 550 MW of Power and 185 ton/hr of Steam 60,000 Nm 3 /hr of High Purity Hydrogen Technologies Selexol Process (Sulfur Removal) Polysep Membranes (H 2 Purification) Polybed PSA (H 2 Purification) High Purity H 2 to Hydrocracker Electric Power Steam for Export Polybed TM PSA Raw H 2 O 2 from Air Separation Unit Combined Cycle Power Plant Treated Syngas Polysep TM Membranes Feed Gasifier with Quench & Scrubbing Gas Cooling & COS Hydrolysis Selexol TM Process Claus SRU Elemental Sulfur Tail Gas

4 Saras IGCC Plant Block Flow Diagram Tail Gas from SRU Acid Gas to SRU Gasifier Unit 301 Power Steam Gasifier Unit 302 Gas Cooling & COS Hydrolysis Unit 401 Gas Cooling & COS Hydrolysis Unit 402 Selexol Process Unit 501 Selexol Process Unit 502 By-pass Membranes Nonpermeate Combined Cycle Power Plant Gasifier Unit 303 Raw H 2 PSA (8 bed) PSA (6 bed) Technology Partners Other Licensors Capacity increased from 40,000 to 60,000 Nm 3 /h H 2 requiring installation of an additional 6-bed PSA H 2 to Refinery

5 REMOVAL PURIFICATION Overview Saras IGCC - Acid Gas Removal (Selexol Process) Topic 1 Maximum Capacity Test Topic 2 Sulfur Loading Fluctuations Topic 3 Operational Issues & Improvements Saras IGCC - H 2 Purification (Polysep Membranes + Polybed PSA) Topic 4 Design Philosophy Topic 5 Historical Time Line

6 Topic 1 - AGRU Maximum Capacity Test Gas Solvent Flash Gas to Unit 401 F Compressor Treated Gas to Membranes & Power Plant Flash Gas from Unit 502 Flash Gas from Unit 501 Test Run of 2007 Acid Gas to SRU COS Hydrolysis Unit 401 Selexol Process Absorber Unit 501 Rich Solvent Flash Drum Selexol Process Regenerator Unit 502 Syngas from Gasifier A Tail Gas from SRU B Lean Solvent Flexibility Selexol Process Units can handle up to 116% of design flow rates while still meeting all Treated Gas specifications

7 Topic 2 - AGRU Sulfur Loading Fluctuations Test Run of 2010 H 2 S content of syn-gas from gasifiers fluctuating from 0.2 to 1.2% On average 40 ppmv Total Sulfur in Treated Gas from Selexol Process 20 ppmv SOX in Stack Exhaust from Power Plant Flexibility Selexol Process generates on-spec Treated Gas although Sulfur Loading in Raw Syngas is fluctuating

8 Topic 3 - AGRU Operational Issues Water content (Wt-%) Temperature ( C) Formate in lean solvent (mg/l) Operational Issues Corrosion in Regenerator due to condensation of formic acid from formates accumulated in solvent (too low water purge rate & heat input) Fouling of Lean/Rich Exchanger due to corrosion by-products (insufficient filtration)

9 Topic 3 - AGRU Operational Improvements Water content (Wt-%) Temperature ( C) Formate in lean solvent (mg/l) Operational Issues Resolved No corrosion issues reported since 2005 (adjusted water purge flow rate + adequate heat input & heat tracing) No unexpected shut-downs because of fouling since 2009 (heat exchanger maintenance program + improved filtration)

10 REMOVAL PURIFICATION Overview Saras IGCC - Acid Gas Removal (Selexol Process) Topic 1 Maximum Capacity Test Topic 2 Sulfur Loading Fluctuations Topic 3 Operational Issues & Improvements Saras IGCC - H 2 Purification (Polysep Membranes + Polybed PSA) Topic 4 Design Philosophy Topic 5 Historical Time Line

11 Topic 4 - H 2 Purification Design Philosophy (1) Feed to membrane unit Permeate (to PSA Unit) Permeate (to PSA Unit) Non-Permeate (to Power Plant) Feed to membrane unit (= product from Selexol Unit) Feed to PSA unit (= product from membrane unit) CO % 11.58% H % 82.72% CO 41.84% 5.17% CH 4 + inerts 4.13% 0.37% Design Philosophy Polysep Membranes are used to increase hydrogen content of the feed to PSA Unit

12 Topic 4 - H 2 Purification Design Philosophy (2) By-pass Treated Syngas Non-Permeate Membrane Unit To Power Plant Hydrogen Product Permeate (Raw H 2 ) H 2 Product Compressor PSA Unit To Refinery Purity of 99.9% Delivered at maximum 46 barg Design capacity of 40,000 Nm 3 /hr H 2 Compressor PSA Tail Gas Compressor Basis of Design 464,364 Nm 3 /hr (416 MMscfd) Feed to Membranes 26.8 bara (388 psia) 58,260 Nm 3 /hr (52 MMscfd) Feed to PSA Unit 18.5 bara (270 psia) Design Philosophy Combination of Polysep Membranes and Polybed PSA reduces flow rate of PSA Tail Gas stream significantly

13 Topic 5 - H 2 Purification Historical Time Line Production of 60,000 Nm 3 /hr of high purity H 2 How to handle increased permeate flow rate? Addition of extra 6-bed PSA Addition of permeate compressor & tailgas compressor Revamp of existing hydrogen compressors How to increase hydrogen production? Use of new type of membranes (higher permeate flow rate) All membrane banks in service + membrane life time > 5 years Long Term Solution - improved feed conditioning (membranes) High efficiency mesh blankets in overhead of Absorber Pall SepraSol Gas-Liquid Coalescers in KO drums Short Term Solution - sacrificial cartridges Frequent change-out of membrane cartridges Operational Issues - reduced membrane life Membrane fibers damaged by solvent carry-over

14 Q&A High Purity H 2 to Hydrocracker Electric Power Steam for Export Polybed TM PSA Raw H 2 O 2 from Air Separation Unit Combined Cycle Power Plant Treated Syngas Polysep TM Membranes Feed Gasifier with Quench & Scrubbing Gas Cooling & COS Hydrolysis Selexol TM Process Claus SRU Elemental Sulfur Tail Gas