H2S Treatment of Landfill Gas at the Roosevelt Landfill

Daniel Waineo, Principal GC Environmental 107 SE Washington Street

Suite 243 Portland, OR 97214

Phone: 503-234-7984

E-mail: dwaineo@gc-environmental.com

Kevin Ricks Klickitat Public Utility District

Phone: (509) 773-7430

E-mail: kricks@klickpud.com

Phone: 503-234-7984

LFG Gas Treatment at Roosevelt

Landfill Gas Blower

First Stage Screw

Compressor

H2S Treatment

Aftercooler 1

Aftercooler 2

Dehydration

Siloxane Removal

Carbon Backup Vessels

Pipeline

Second Stage Screw

Compressor

Aftercooler 3

Mars Solar Turbines

Existing System

2013 Work

Phone: 503-234-7984

Landfill Gas Blowers/Flares

Phone: 503-234-7984

First Stage Compressors

Phone: 503-234-7984

Aftercooler 1

Phone: 503-234-7984

H2S Treatment

Phone: 503-234-7984

Aftercooler 2

Phone: 503-234-7984

Dehydration System

Glycol Pumps/Double Wall Tank

Phone: 503-234-7984

Dehydration System

New Chiller/Pipebridge

Phone: 503-234-7984

Dehydration System

Heat Exchangers/ Coalescing Filter

Phone: 503-234-7984

Siloxane Removal

Phone: 503-234-7984

Carbon Backup Vessels

Phone: 503-234-7984

Second Stage Compression

Phone: 503-234-7984

LFG Pipeline

Phone: 503-234-7984

Second Stage Compressor Cooler

Phone: 503-234-7984

Solar Mars 90 Turbines (2 x 10 MW) Combined Cycle

Phone: 503-234-7984

Upper and Lower Sites

Phone: 503-234-7984

Lower Compression Area

Phone: 503-234-7984

Turbine Plant

Phone: 503-234-7984

History of H2S treatment at Roosevelt

Old System (IC Engines 199x) ◦ Iron Sponge

Temporary New System for Turbines (2011) ◦ Sulfatreat

Final System (Summer 2013) ◦ Chelated Iron Hydrogen Sulfide Treatment

Phone: 503-234-7984

Solid Scavengers – Iron Sponge

Iron Sponge ◦ Dry Media of Iron-Oxide on Wood chips ◦ Does best using warm wet gas with Oxygen

◦ 4000 SCFM Treating 300 ppmv H2S

Phone: 503-234-7984

Solid Scavengers – Iron Sponge

Advantages ◦ Simple system ◦ Can be regenerated to some extent with a small Oxygen Stream ◦ Fairly low capital costs

Disadvantages ◦ Exothermic during media Regeneration/ Removal ◦ Costs for Media Replacement and Disposal of spent material ◦ Inconsistent Media Shape

Phone: 503-234-7984

Solid Scavenger – Sulfatreat

Sulfatreat (iron oxide on ceramic beads) ◦ Does best with warm, humid landfill gas with a small amount of Oxygen

◦ 6000 SCFM at 50 psig with 60 ppmv H2S

Phone: 503-234-7984

Solid Scavenger - Sulfatreat

Advantages ◦ Very simple system ◦ May be exothermic during media replacement ◦ Fairly low capital cost ◦ Uniform media shape

Disadvantages ◦ Media replacement costs ◦ Spent media disposal costs ◦ Water may be required to break and flush media from bed

Phone: 503-234-7984

Chelated Iron Processes

LO CAT® SulFerox®

Treatment at KPUD: ◦ Unlicensed Iron Chelate Process

Thanks to: ◦ Dow Chemical Provides chemicals and technical assistance

◦ Westfield Engineering Provided P&IDs Provided spargers vessels and heater skid

Phone: 503-234-7984

Chelated Iron Treatment

Unlicensed Chelated Iron Treatment System

Inle

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Spa

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Tow

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Out

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Sep

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Reg

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Settling Tank

Treated LFG

Sulfur Cake

Phone: 503-234-7984

Chelated Iron Treament

Chemistry Treatment: ◦ H2S + Fe+3L 2H+ + SO + Fe+2L

Regeneration: ◦ 1/2O2 + 2H+ + 2Fe+2L-> H2O + 2Fe+3L

Chelates: ◦ Keep the Iron in solution

Others: Caustic, Surfactants, degradation inhibitors

Phone: 503-234-7984

Chelated Iron Treatment

Sparger Vessels

Phone: 503-234-7984

Chelated Iron Treatment

Pipe Bridge

Phone: 503-234-7984

Chelated Iron Treatment

Regeneration and Settling Tanks

Phone: 503-234-7984

Chelated Iron Treatment

Heater Skid

Phone: 503-234-7984

Chelated Iron Treatment

Iron Chelate Pumps

Phone: 503-234-7984

Chelated Iron Treatment

Chemical Pumps

Phone: 503-234-7984

Chelated Iron Treatment

Sulfur Filter and Sulfur Cake

Phone: 503-234-7984

Insulated Dehydration System

Phone: 503-234-7984

Insulated Glycol Tank/Pumps

Phone: 503-234-7984

Insulated Settler Tanks

Phone: 503-234-7984

Insulated Heater Skid

Phone: 503-234-7984

Chelated Iron Treament

Advantages ◦ Low Cost of Operation ◦ No disposal (except sulfur cake) ◦ Continuous process Disadvantages ◦ High Capital Costs ◦ Process operates warm

Performance ◦ Inlet: 250 ppmv H2S ◦ Outlet:

Phone: 503-234-7984

Sulfur Plugging Issues

Heat exchanger plugging

Phone: 503-234-7984

Cake Consistency Issues

Phone: 503-234-7984

Sulfur Cake

Phone: 503-234-7984

Lessons Learned

Very reliable system that has been treating continuously since startup in July 2013

0.25% Oxygen in landfill gas is sufficient for regeneration (regenerator currently is bypassed)

100 lbs of Sulfur made per day (no market found yet)

Chemical use is a little higher than predicted (especially Caustic)

Phone: 503-234-7984

LFG H2S Treatment

Questions?

Kevin Ricks Klickitat Public Utility District (509) 773-7430

Daniel Waineo, P.E. GC Environmental (503) 234-7984

H2S Treatment of Landfill Gas at the Roosevelt LandfillLFG Gas Treatment at RooseveltLandfill Gas Blowers/FlaresFirst Stage CompressorsAftercooler 1H2S TreatmentAftercooler 2Dehydration SystemDehydration SystemDehydration SystemSiloxane RemovalCarbon Backup VesselsSecond Stage CompressionLFG PipelineSecond Stage Compressor CoolerSolar Mars 90 Turbines (2 x 10 MW) Combined CycleUpper and Lower SitesLower Compression AreaTurbine PlantHistory of H2S treatment at RooseveltSolid Scavengers – Iron SpongeSolid Scavengers – Iron SpongeSolid Scavenger – Sulfatreat�Solid Scavenger - SulfatreatChelated Iron ProcessesChelated Iron TreatmentChelated Iron TreamentChelated Iron TreatmentChelated Iron TreatmentChelated Iron TreatmentChelated Iron TreatmentChelated Iron TreatmentChelated Iron TreatmentChelated Iron TreatmentInsulated Dehydration SystemInsulated Glycol Tank/PumpsInsulated Settler TanksInsulated Heater SkidChelated Iron TreamentSulfur Plugging IssuesCake Consistency IssuesSulfur CakeLessons LearnedLFG H2S Treatment