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MWEA Biosolids and Energy
ConferenceTechnologies for Biogas Conditioning
March 3 and March 4, 2009
Unison Solutions Overview
� Biogas compression/treatment system design and fabrication (Siloxane, moisture and H2S removal)
� 75 systems in operation� Turnkey waste-to-energy systems� Gas conditioning system components
(suction scrubbers, heat exchangers, filtration, condensate knock-outs, etc.)
� Custom System Design and Fabrication
Unison Solutions Overview (cont)� Stainless Steel Vessel Fabrication
(ASME Pressure Vessels)
� Capstone MicroTurbine distributor and service provider (10 states)
� Automation and UL panel shop
� Gas testing and analysis
� Multiple awards for Biogas systems (EPA project of the year 2003, 2006 SWANA Gold Award)
Fabrication Facility
Assembly and Testing Area 800scfm Gas Treatment System
A Sampling of Unison Solutions Biogas Projects
WWTF/Industrial Digesters1. Rockford IL-2.25 MW Waukesha Engine CHP2. Milwaukee South Shore – Gas Compression3. Albert Lea MN-4 Turbine CHP 4. Sheboygan WI-10 Turbine CHP 5. St. Petersburg, FL – 9 Turbine 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
20scfm Gas Treatment System
Dublin San Ramon CA-WWTF FCE Fuel Cell Installation
Biogas Treatment Systems
What is driving the need for increased gas treatment on biogas fueled generation and direct use projects?
Equipment Damage and Performance Issues
Key System Components
� Hydrogen Sulfide Removal� Moisture Removal� Compressor or Blower� Siloxane Removal� CO2 Removal
Typical Gas Treatment System
Why Hydrogen Sulfide Removal?
� Equipment Damage from Corrosion (Hydrosulfuric Acid)
� Health and Safety Issues (1000ppm will cause an individual to go unconscious)
� Odor Control� Causes fouling of siloxane removal
media
Types of H2S Removal
� Media Based- Iron Sponge- SulfaTreat
� Liquid H2S Removal- SulfrStrip (AFT)- Amine Solutions
� Biological- NATCO Shell-Paques- Amine Solutions- Biothane Biopuric
MMSD 800scfm Iron Sponge
Natco Group Amine System
Biothane Biopuric Biological System
Why Moisture Removal?
� Prevents condensation downstream� Improves energy content of gas� Condenses into compressors� Formation of weak acids from
interaction with H2S and CO2� Fouling of Siloxane removal systems
Types of Moisture Removal Equipment
� Knockout� Suction Scrubber or De-mister� Ambient Air Cooler� Refrigerated Dryer� Glycol Chilling
Suction Scrubber or De-Mister
Ambient Air Cooler
Refrigerated Dryer
Unison “Uni-Chiller” Glycol Chiller
Why Siloxane Removal?
� Organosilicons produced by Dow Chemical� Used 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 Problem
�When 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 microturbines
� Usage in commercial products is increasing at 5% to 10% annually.
� Problems with Siloxanes are here to stay.
Siloxane Damaged Piston
Siloxane Buildup on Cylinder Head
Silica Layer½” to 1” Thick
Pitting of Boiler Tubes
Processes for Removing Siloxanesfrom Biogas
� Fixed Bed Carbon Filters (AFT SAG, Calgon, Carbon Air)
� Fixed Bed Silica Gel Bead Filters (AFT)� Regenerated Desiccants (Domnick
Hunter)� Regenerated Carbon (Jenbacher TSA)� Regenerated Graphite (AFT SWOP)� Regeneration with Micro Wave
AFT SAG Fixed Bed Process
Jenbacher TSA System
AFT SWOP Gas Treatment Process
Unison Typical Gas Treatment
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 (Air Liquide)� Solvent-Polyethylene Glycol Absorption
(Selexol)
Quest Air M3100 PSA CO2 Removal System
QuestAir PSA Process
End Use Opportunities
� Direct Use-Boiler Fuel� Electrical Generation-IC Engines, Fuel
Cells, Turbines� Distribution Pipeline Injection� Compressed gas for vehicle fuel
Unison Solutions Project Support Summary
� Biogas compression/treatment system design and fabrication (Siloxane, moisture and H2S removal)
� Blower skids� Gas conditioning system components
(suction scrubbers, heat exchangers, filtration, condensate knock-outs, etc.)
� Vessel Fabrication� Capstone MicroTurbine distributor and
service provider (10 states)� Gas testing and analysis
TEST and TREAT YOUR BIOGAS
Unison Solutions Contact Information
Jan Scott and Dave Broihahn
