Energy Savings Opportunities for Indiana WWTF Solutions Overview Biogas compression/treatment system...
Transcript of Energy Savings Opportunities for Indiana WWTF Solutions Overview Biogas compression/treatment system...
Energy Savings Opportunities for Indiana
WWTFTechnologies for Biogas Conditioning
May 19 and May 21 2008
Unison Solutions OverviewBiogas compression/treatment system design and fabrication (Siloxane, moisture and H2S removal) Custom stainless steel vessel fabricationTurnkey waste-to-energy systemsUL Panel shop and automation systemsGas conditioning system components (suction scrubbers, heat exchangers, filtration, condensate knock-outs, etc.)Capstone MicroTurbine distributor and service provider (10 states)OEM Supplier for Capstones new integrated Biogas packageGas testing and analysisMultiple awards for Biogas systems (EPA project of the year 2003, 2006 SWANA Gold Award)
A Sampling of Unison Solutions Biogas Projects
WWTF/Industrial Digesters1. Rockford IL-2.25 MW Waukesha Engine CHP2. Chippewa Falls WI-2 Turbine CHP3. Albert Lea MN-4 Turbine CHP 4. Sheboygan WI-10 Turbine CHP 5. Top Deck Farms IA-4 Turbines CHP6. Tulare CA WWTF-Gas Treatment for Fuel Cells7. Dublin San Ramon CA WWTF-Gas Treatment for
Fuel Cells8. Durango CO WWTF-2 Turbine CHP9. Flagstaff AZ WWTF-Jenbacher Generator CHP10. MMSD-Gas Treatment for Waukesha Gen Sets
Biogas Treatment Systems
What is driving the need for increased gas treatment on biogas fueled generation and direct use projects?
Key System Components
Hydrogen Sulfide RemovalMoisture RemovalCompressor or BlowerSiloxane RemovalCO2 Removal
Why Hydrogen Sulfide Removal?
Equipment Damage from Corrosion (Hydrosulfuric Acid)Health and Safety Issues (1000ppm will cause an individual to go unconscious)Odor ControlCauses fouling of siloxane removal media
Types of H2S RemovalDry H2S Removal
- Iron Sponge- Iron Oxides- Zinc Oxides- Alkaline Solids
Molecular Sieve- Zeolites- Impregnated Activated Carbons
Liquid H2S Removal- Liquid-Phase Oxidation- Amine Solutions- Iron Chlorides - Biological- Water Stripping
O&M Cost of H2S Removal Systems
Iron Sponge-best used for 250lbs/day H2S removal. $1.65/lb of sulfur removedIron Oxides-best used for 250lbs/day H2S removal. $2.25/lb of sulfur removedActivated Carbon-best used for 20lbs/day H2S removal. $2.30/lb of sulfur removedAmine Solutions-best used for 500lbs/day H2S removal. $4.70/lb of sulfur removedBiological Process-best for high amount of H2S removal. $0.17/lb of sulfur removed but high capital cost
Why Moisture Removal?
Prevents condensation downstreamImproves energy content of gasCondenses into compressorsFormation of weak acids from interaction with H2S and CO2Fouling of Siloxane removal systems
Types of Moisture Removal Equipment
KnockoutSuction Scrubber or De-misterAmbient Air CoolerRefrigerated DryerGlycol Chilling
Why Siloxane Removal?
Organosilicons produced by Dow ChemicalUsed in the manufacture of many commercial products including: makeup, tooth paste, shampoo, lubricants, etc.Present in almost all digester gas from 500ppbv to 140,000ppbv. MM, D4 and D5 account for 75% to 95% in biogas. (2, 4 and 5 silicon atoms per molecule.Do not breakdown during processing at WWTFs or in Landfills
The ProblemWhen VOCs and Siloxanes are in the digester
gas:Combustion of VOCs containing only carbon
hydrogen and oxygen forms carbon dioxide and water vapor.
Combustion of Siloxanes forms carbon dioxide, water vapor, and silicon dioxide, which is a solid and is also the main ingredient in sand. Since this is not a gas, some of it stays in the engine.
The Damaging Results
Pressure and temperature transform the Siloxanes into various abrasive silica forms from sand to glass.Causes damage to boilers, internal combustion engines and microturbinesUsage in commercial products is increasing at 5% to 10% annually.Problems with Siloxanes are here to stay.
Processes for Removing Siloxanes from Biogas
Fixed Bed Carbon Filters (AFT SAG, Calgon, Carbon Air)Fixed Bed Silica Gel Bead FiltersRegenerated Desiccants (Domnick Hunter)Regenerated Carbon (Jenbacher TSA)Regenerated Graphite (AFT SWOP)Regeneration with Micro Wave
Why CO2 Removal?
Opportunity to create a fuel that can be injected into a pipeline Create a compressed vehicle fuel equivalent to CNG
CO2 Removal Processes
PSA-Pressure Swing Absorption (QuestAir, Molecular Gate)Membrane Separation (AFT, Air Liquide)Solvent-Polyethylene Glycol Absorption (Selexol)Water Stripping
End Use Opportunities
Direct Use-Boiler FuelElectrical Generation-IC Engines, Fuel Cells, TurbinesDistribution Pipeline InjectionCompressed gas for vehicle fuel