Abstract |
The paper summarizes work performed by EPA/AEERL at its in-house woodstove test laboratory over the past several years, including investigations into the effects of augmenting the secondary combustion process with electric glowplugs and extensive tests on two EPA 1990 certified stoves, directed at achieving lower emissions by retuning the primary and secondary air controls. Most emission tests have been done while burning split oak cordwood. The work, termed noncatalytic technology, involves maintaining gas temperatures above the ignition point even at low burnrates without using a catalyst, by restricting heat transfer in an insulated secondary combustion chamber, and by providing adequate fresh preheated air to the secondary combustion zone. This represents one of two basic approaches to reducing emissions from residential woodstoves by enhancing the secondary combustion process. All cordwood-burning woodstoves operate in an air-starved mode which promotes the generation of products of incomplete combustion (PICs), including CO and a wide range of organic compounds. The heavier molecular weight organics condense into a fine aerosol upon entering the atmosphere, producing visible smoke. A large percent of these PICs must be oxidized to CO2 and water by enhancing the combustion process outside of the primary combustion zone. |