Document Detail


Simulation of stack plume opacity.
MedLine Citation:
PMID:  10842950     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The visual impact of primary particles emitted from stacks is regulated according to stack opacity criteria. In-stack monitoring of the flue gas opacity allows plant operators to ensure that the plant meets U.S. Environmental Protection Agency opacity regulations. However, the emission of condensable gases such as SO3 (that hydrolyzes to H2SO4), HCl, and NH3, which may lead to particle formation after their release from the stack, makes the prediction of stack plume opacity more difficult. We present here a computer simulation model that calculates the opacity due to both primary particles emitted from the stack and secondary particles formed in the atmosphere after the release of condensable gases from the stack. A comprehensive treatment of the plume rise due to buoyancy and momentum is used to calculate the location at which the condensed water plume has evaporated (i.e., where opacity regulations apply). Conversion of H2SO4 to particulate sulfate occurs through nucleation and condensation on primary particles. A thermodynamic aerosol equilibrium model is used to calculate the amount of ammonium, chloride, and water present in the particulate phase with the condensed sulfate. The model calculates the stack plume opacity due to both primary and secondary particles. Examples of model simulations are presented for three scenarios that differ by the emission control equipment installed at the power plant: (1) electrostatic precipitators (ESP), (2) ESP and flue gas desulfurization, and (3) ESP and selective catalytic reduction. The calculated opacity is most sensitive to the primary particulate emissions. For the conditions considered here, SO3 emissions showed only a small effect, except if one assumes that most H2SO4 condenses on primary particles. Condensation of NH4Cl occurs only at high NH3 emission rates (about 25 ppm stack concentration).
Authors:
R Z Meng; P Karamchandani; C Seigneur
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of the Air & Waste Management Association (1995)     Volume:  50     ISSN:  1096-2247     ISO Abbreviation:  J Air Waste Manag Assoc     Publication Date:  2000 May 
Date Detail:
Created Date:  2000-07-14     Completed Date:  2000-07-14     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9503111     Medline TA:  J Air Waste Manag Assoc     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  869-74     Citation Subset:  IM    
Affiliation:
Atmospheric and Environmental Research, Inc., San Ramon, California, USA.
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MeSH Terms
Descriptor/Qualifier:
Aerosols
Air Pollution / analysis*
Computer Simulation*
Particle Size
Power Plants*
Sulfuric Acids / analysis*,  chemistry
Chemical
Reg. No./Substance:
0/Aerosols; 0/Sulfuric Acids; 7664-93-9/sulfuric acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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