Technical Bulletin No. 0072: An Investigation of Source Particulate Measurement Procedures, Particle Sizes, and Practiced Control Technology for Wood Fuel-Fired Boilers (AQTB)

The attached technical bulletin prepared by Rodney Schmall, formerly NCASI Research Engineer, under the direction of Andre L. Caron, West Coast Regional Engineer, is based on a program of source particulate measurements and particle sizing studies which was begun in 1970 on power boilers burning almost exclusively wood-derived fuels. The bulletin describes the types of boilers used to burn wood-derived fuels and the effect of their design and operation on the nature and amount of particulates escaping the combustion zone. Several facets of particulate emission control are covered in detail. The particulate collection efficiency of components of particulate sampling devices including alundum thimbles and impingers was investigated and reported here. The size of particulates remaining in the emissions of boilers equipped with conventional mechanical collectors was also measured using both inertial impact collectors and microscopic sizing procedures. The merits of each of these procedures in defining the nature of particulates passing collectors are outlined. Finally, particulate emission data on wood fuel-fired power boilers sampled during this study and emission data for such boilers from several other sources that was available in late 1972 and early 1973 was compiled. This information then represents the state of the art of particulate emission control technology that existed as of 1973.