Sw. Lee, Source profiles of particulate matter emissions from a pilot-scale boiler burning north American coal blends, J AIR WASTE, 51(11), 2001, pp. 1568-1578
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology,"Environmental Engineering & Energy
Recent awareness of suspected adverse health effects from ambient particula
te matter (PM) emission has prompted publication of new standards for fine
PM with aerodynamic diameter less than 2.5 mum (PM 2.5). However, scientifi
c data on fine PM emissions from various point sources and their characteri
stics are very limited. Source apportionment methods are applied to identif
y contributions of individual regional sources to tropospheric particulate
concentrations. The existing industrial database developed using traditiona
l source measurement techniques provides total emission rates only, with no
details on chemical nature or size characteristics of particulates. This d
atabase is inadequate, in current form, to address source-receptor relation
ships.
A source dilution system was developed for sampling and characterization of
total PM, PM2.5, and PM10 (i.e., PM with aerodynamic diameter less than 10
pm) from residual oil and coal combustion. This new system has automatic c
ontrol capabilities for key parameters, such as relative humidity (RH), tem
perature, and sample dilution. During optimization of the prototype equipme
nt, three North American coal blends were burned using a 0.7-megawatt therm
al (MWt) pulverized coal-fired, pilot-scale boiler. Characteristic emission
profiles, including PM 2.5 and total PM soluble acids, and elemental and c
arbon concentrations for three coal blends are presented. Preliminary resul
ts indicate that volatile trace elements such as Pb, Zn, Ti, and Se are pre
ferentially enriched in PM2.5* PM2.5 is also more concentrated in soluble s
ulfates relative to total PM. Coal fly ash collected at the outlet of the e
lectrostatic precipitator (ESP) contains about 85-90% PM10 and 30-50% PM2.5
* Particles contain the highest elemental concentrations of Si and Al while
Ca, Fe, Na, Ba, and K also exist as major elements. Approximately 4-12% of
the materials exists as soluble sulfates in fly ash generated by coal blen
ds containing 0.2-0.8% sulfur by mass. Source profile data for an eastern U
.S. coal show good agreement with those reported from a similar study done
in the United States. Based on the inadequacies identified in the initial s
ampling equipment, a new, plume-simulating fine PM measurement system with
modular components for field use is being developed for determining coal co
mbustion PM source profiles from utility boiler stacks.