03/01880 Size and chemical characteristics of fine particulate emissions from oil and coal-fired pilot scale boilers: Lee, S. W. et al. Preprints of Symposia - American Chemical Society, Division of Fuel Chemistry, 2002, 47, (2), 679–680

Abstract

Introduction The Canada Wide Standards for particulate matter (PM) was proposed in Canada in 2000, soon after the publication of the new US National Ambient Air Quality Standards in 1997 . Subsequently, increased research activities were noted in the following years in addressing the apparent knowledge gaps related to fine PM emissions. Measuring PM2.5 and PM10 emissions from combustion sources began to replace the traditional means of monitoring and reporting of total suspended particulates. Identification and quantification of PM from regional point sources are critical in controlling the PM emissions effectively at source as well as in apportioning the ambient PM concentrations to the contributing local sources. A new methodology was developed to determine fine PM emissions under plumesimulating conditions that are comparable to ambient PM characteristics. The method, unlike traditional high temperature measurement methods, applies initial cooling of the flue gas by diluting with clean air inside an inert tunnel to mimic plume conditions. The source dilution approach allows for atmospheric transformation processes for the PM and thus provides ambientcomparable source signature profiles for source apportionment modeling. At present, fine PM data from industrial sources are limited and often not representative of reality, being derived from high temperature source measurement techniques. Research is being co-sponsored by two Canadian utilities, Environment Canada with the objective of examining source PM characteristics from the electric power generation sector. Two prototype samplers have been developed for the combustion units having low stack velocities (<5 m/s) and medium velocities (<10 m/s). The larger sampler is being retrofitted for field measurement on utility-scale boilers. The basic sampling protocol involves dilution of flue gas with purified air by 20 to 40 times inside a dilution chamber maintained at a 40% relative humidity (RH) to allow for cooling and simulation of atmospheric transformation processes. Portions of the diluted gas are withdrawn, while maintaining isokinetic sampling, through selected cyclone and impactor inlets and filter packs to collect the PM fractions. The method provides mass concentrations of PM2.5, PM10 and total PM and their size and chemical composition information. To date, fine PM emissions from the combustion of No. 2 and No. 4 heating fuels and pulverized coal have been determined and characterized using the two samplers. The paper summarizes the preliminary size and chemical characteristic data from the combustion of three experimental fuels.