Catalytic Emissions Reduction Systems for Outdoor Wood Boilers

There is growing concern about the particulate pollution emitted by outdoor wood-fired boilers (0WBs) and their related health effects. These systems are also referred to as outdoor wood-fired hydronic heaters or outdoor wood-fired furnaces. There are currently over 500,000 OWBs installed, primarily in the northern US. During the Phase I SBIR project, a catalytic combustor system that can be retrofitted onto existing OWBs to reduce their emissions was designed and tested. Testing was conducted on a Central Boiler Model Classic 5036. Results showed that visible smoke emissions were greatly reduced and that particulate emissions were reduced over 50 percent and carbon monoxide emissions were reduced by 65 percent. The Phase II program will further develop testing and measurement protocols, determine the optimum combustor catalyst-support combination, examine supplemental air supply for the combustor redesign the retrofit unit for easy maintenance, conduct testing of non-ideal fuels, and conduct long-term testing. It is expected that results from these tasks will identify an optimum retrofit design for use on existing 0WBs. In the commercialization option program, application of the catalytic combustor to new OWB models and units other than Central Boiler will be examined.