Technical Bulletin No. 0075: Comparison of Source Particulate Emission Measurement Methods for Combination Fuel-Fired Boilers (AQTB)

The studies described herein were initiated in response to member mill representatives' requests for information on suitable procedures for the measurement of source particulate emissions from combination fuel-fired boilers. The field investigations described in this technical bulletin were confined to the measurement of particulate matter emission where flue gas temperature was well above the dew point but where sulfur dioxide concentrations ranged from almost zero to as much as several hundred ppm. The source particulate sampling and analysis procedures chosen for comparison on this source were (a) an external to the stack filtration method in which the gas is cooled from approximately 400°F at these sources to between 250° and 290°F before filtration, which is commonly referred to as the EPA method, and (b) an in-stack filtration method which collects particulate matter on the same glass fibre filtration media used in the EPA source particulate matter measurement procedure, but with the filter temperature maintained at stack temperature, or well above the dew point of sulfur trioxide. The investigation demonstrated that the simpler in-stack filtration procedure is in fact a suitable alternative for the filtration section of the EPA particulate sampling procedure at those sources where wood-derived fuel serves as a portion or all of the total fuel, and where stack gas temperature is maintained above the dew point. The difference in measured particulate concentration by the two methods was insignificant and of the same order of magnitude as the difference in concentration measured when simultaneously sampling with two EPA sampling trains.