Over the last three years I’ve been working extensively on technical issues related to wood-fired biomass heating systems. The boilers used in these systems burn wood pellets or wood chips. In smaller applications, boilers that burn cordwood using two-stage “gasification” combustion also are used.
Many of these boilers are state-of-the-art products that use microprocessor-controlled air/fuel ratio adjustments to produce average cycle efficiencies of more than 75% and particulate emissions lower than 0.08 lb per million Btu. Both performance metrics are much better than what can be achieved using manually regulated single-stage wood-fired combustions systems.