Record Display for the EPA National Library Catalog

RECORD NUMBER: 456 OF 892

OLS Field Name OLS Field Data
Main Title Mechanisms of Dry SO2 Control Processes.
Author Apple, Cathy ; Kelly, Mary E. ;
CORP Author Radian Corp., Durham, NC.;Industrial Environmental Research Lab., Research Triangle Park, NC.
Year Published 1982
Report Number EPA-68-02-3171; EPA-600/7-82-026;
Stock Number PB82-196924
Additional Subjects Air pollution control ; Sulfur dioxide ; Spray drying ; Chemical reactions ; Reaction kinetics ; Mathematical models ; Surfaces ; Calcium oxides ; Sodium inorganic compounds ; Dry methods ; Flue gas desulfurization ; Chemical reaction mechanisms
Holdings
Library Call Number Additional Info Location Last
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Status
NTIS  PB82-196924 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 06/23/1988
Collation 137p
Abstract
The report discusses physical and chemical processes and reaction mechanisms for lime spray drying and dry injection of sodium compounds in dry flue gas desulfurization (FGD) processes. It includes: chemical reactions, physical changes, proposed reaction mechanisms and mathematical models, process parameters affecting reactions and their rates, and data needed to verify proposed reaction mechanisms and models. Published technical papers were the primary reference sources. The report focuses on coal-fired boiler dry FGD applications. Lime spray drying reactions are primarily gas/liquid-phase reactions, with SO2 removal depending on moisture in the lime slurry droplet. Initially, the moisture content is high, and the reaction rate is controlled by diffusion of SO2 to the droplet surface; most SO2 removal occurs during this phase. As evaporation reduces the moisture, the dissolution of Ca(OH)2 into ions limits the SO2 removal rate. Later, the precipitation of CaSO3.1/2 H2O onto the surface of the lime particles retards diffusion of SO2 to the unreacted sorbent. Injecting sodium compound powders into flue gas removes SO2 via gas/solid reactions. First, NaHCO3 is thermally decomposed to Na2CO3 (small pores in the sorbent particles increase the particles' surface area and reactivity). Then the SO2 reacts with Na2CO3 to form Na2SO3, starting at the particle surface.