Operation and Emissions of a Hybrid Stove Fueled by Pellets and Log Wood

摘要

Small-scale wood combustion in wood-log fired appliances is commonly used for heat production in residential buildings, leading to significant particle and gaseous emissions and impaired air quality. Thus, there is a need for effective emission reduction methods for residential wood combustion. In this work, the operation and emissions of a novel hybrid stove, i.e a slow heat releasing appliance capable of using both wood pellets and log wood as fuel, were studied. While log wood operation in this stove represents conventional combustion technology, the operation and emission performance of the pellet burner system is demonstrated for the first time. Particle and gaseous emissions were carefully characterized under various operating conditions, including real-time measurements of particle mass, number, and size, as well as analyses of the particulate chemical composition of filter samples. The use of pellet fuel decreased the fine particle emissions by 92% and the CO emissions by 65% compared with the log wood combustion. Operational practices in the log wood combustion affected the gaseous emissions but only had a minor effect on the particle emissions. The fine particle emissions from the pellet combustion were mostly comprised of elemental carbon (soot) particles. The real time measurements showed that most of the particle emissions were formed after ignition, for both fuels, whereas the end of combustion proved to be important for carbon monoxide., emissions. This study shows that the novel pellet batch burner used in a hybrid stove can be used as an effective low-cost solution to reduce the emissions from residential wood combustion. The advantage of this system is that it requires no automation and thus an electricity supply is not required.