Understanding the Reduction of Indoor PM2.5 Emissions by Using the Two-Dimensional Nature of Wood Pyrolysis
JOHN FLYNN, Tami Bond,
Colorado State University Abstract Number: 529
Working Group: Indoor Aerosols
AbstractIndoor air pollution remains a challenge for many worldwide. A major contributing source of PM2.5 indoors is the use of wood burning stoves which use large pieces of wood fuel with inefficient burning. When starting and operating a cookfire the first and unavoidable stage is the pyrolysis stage. This stage, which proceeds flaming combustion, has been shown to contribute the majority of PM2.5 emission during the combustion process. One solution to reducing these emissions lies in a more rapid transition from pyrolysis to flaming combustion. Technologies have been developed in stove design communities to improve combustion emissions; however, many households across the globe face financial hurdles preventing them from acquiring this technology. Although advanced stove technology can improve fuel emissions, the transition from pyrolysis to sustained combustion through more rapid ignition also acts to reduce PM2.5 ejection from the wood fuel. Our approach involves reduction of PM2.5 emissions by identifying fuel preparation techniques that serve to cause ignition to occur quickly during the initial transient stage of burning. These techniques are rooted in heat and mass transfer concepts, foremost of which is termed ‘critical mass flux’. We show how modifying wood fuel to expose end grain surface area leads to achieving the critical mass flux required to decrease time to ignition. We take advantage of the naturally occurring two-dimensional heat and mass transfer to better suit the budgets of families in developing countries. The best part: it’s free.