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January 19, 2010 Wood-Fired Boiler Emission Control Update Prepared for: 2010 Vermont Wood Chip Users Conference
January 19, 2010
Wood-Fired Boiler Emission Control Update
Prepared for:2010 Vermont Wood Chip Users Conference
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Wood-Fired Boiler Emission Control Update
Overview
Quick review of add-on emission controls
What’s new?
Best Management Practices (BMPs)
Electrostatic Precipitators (ESPs) advantages
Parting thoughts
Photo provided by the Biomass Energy Resource Center (BERC)
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Wood-Fired Boiler Emission Control Update
Quick Review of Common Add-On Pollution Controls
Mechanical collectors– Use inertial separation– Commonly found on smaller school systems (< 10 MMBtu/hr)– Types: single cyclones, multi-cyclones, high efficiency multi-
cyclones, core separators
Baghouses– Use fabric filtration – Common on larger systems (> 10 MMBtu/hr)
Electrostatic precipitators (ESPs)– Use electrostatic attraction– Common on very large systems (> 100 MMBtu/hr) and about to
become common on smaller systems
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Wood-Fired Boiler Emission Control Update
Photos provided by the Biomass Energy Resource Center (BERC)
Add-On Pollution Controls
Single Cyclone
High Efficiency Multi-Cyclone
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Wood-Fired Boiler Emission Control Update
Photo provided by Easom Consulting
Add-On Pollution Controls
Core Separator
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Wood-Fired Boiler Emission Control Update
Add-On Pollution Controls
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Wood-Fired Boiler Emission Control Update
Add-On Pollution Controls
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Wood-Fired Boiler Emission Control Update
What’s new?
Stricter emission limits should become reality in 2010
Vermont APCD control study completed (inlet/outlet testing at 5 NE sites)
First pellet boiler stack emission test completed (2.8 MMBtu/hr system)
Best Management Practices (BMPs) can substantially reduce emissions
Mechanical collector performance sub-optimal
Electrostatic Precipitators (ESPs) have many potential advantages
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Wood-Fired Boiler Emission Control Update
ESP Benefits
More economical than originally thought, but still expensive relative to
simple mechanical collectors
Occupy a small footprint
Can be installed outdoors
Less ancillary equipment (eg insulated ductwork)
Relatively low power requirements relative to all add-on pollution
controls
Low maintenance relative to baghouse
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Wood-Fired Boiler Emission Control Update
ESP Benefits
Photo courtesy of BETH ESPs
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Wood-Fired Boiler Emission Control Update
Best Management Practices (BMPs)
Focus historically on add-on controls. Need more BMPs
Also called work practice standards
In short – what can be done upstream of the pollution control device to reduce emissions?
Improve system efficiency (reduce fuel consumption and emissions)
Improve system performance (avoid upset conditions with uniform fuel)
Data reviewed and work experiences indicate they do make a difference
Poor fuel quality doubled normal level particulate emissions
Boiler tune up reduced particulate emissions by approx 60%
Lower ash content fuel eliminated clinkers and saved grates
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Wood-Fired Boiler Emission Control Update
Best Management Practices (BMPs) – partial list
Fuel quality
Operation and maintenance plan
Boiler operator training
Equipment sensors
Automatic ash removal
Raking grates
Combustion efficiency testing
Visual plume observations
Annual tune up
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Wood-Fired Boiler Emission Control Update
Parting Thoughts
BMPs can save energy, reduce emissions and eliminate hassles
Consider designing emission control systems to meet stricter emission
limits
ESP looks like a good bet, but don’t rule out other options
Don’t bet on conventional mechanical collectors to meet stricter
emission limits
Mechanical collectors should maintain pressure drop over all firing
rates
Final USFS emissions report in a few months
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Emissions Controls for Wood Boilers
Contact Information
John Hinckley
Resource Systems Group, Inc.
55 Railroad Row
White River Junction, VT 05001
802/295-4999
www.rsginc.com
