Effects of salts on preparation and use of calcium silicates for flue gas desulfurization

Journal Article · Tue Feb 01 00:00:00 EST 1994 · Environmental Science and Technology; (United States)

DOI:https://doi.org/10.1021/es00051a014· OSTI ID:5198807

Kind, K K; Wassermann, P D; Rochelle, G T ^[1]

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1. Univ. of Texas, Austin, TX (United States)

High surface area calcium silicate hydrates that are highly reactive with SO[sub 2] can be made by slurrying fly ash and lime in water at elevated temperatures for several hours. This concept is the basis for the ADVACATE (ADVAnced siliCATE) process for flue gas desulfurization. This paper examines the impact of salts on such a system. Two low calcium fly ashes, from the Shawnee and Clinch River power plants, were examined. The addition of gypsum (CaSO[sub 4][center dot]2H[sub 2]O) or calcium chloride to the slurry system increased the dissolved calcium concentration, allowing the reaction rate to increase and the maximum surface area to more than double in some cases. This increase came despite a lower solution hydroxide level. The salts also enhanced the reaction of the sorbent with sulfur dioxide. This resulted from the higher equilibrium moisture on the sorbent at any humidity due to the deliquescent properties of some of the salts used (calcium chloride and calcium nitrate). Solids made without the deliquescent salts exhibited equilibrium moisture adsorption consistent with a type-II BET isotherm while the deliquescent salts caused hysteresis in the adsorption/desorption isotherm. 22 refs., 10 figs., 2 tabs.

• OSTI ID: 5198807
• Journal Information: Environmental Science and Technology; (United States), Vol. 28:2; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
54 ENVIRONMENTAL SCIENCES
ADSORPTION ISOTHERMS
HYSTERESIS
CALCIUM OXIDES
CHEMICAL REACTIONS
CALCIUM SILICATES
CHEMICAL PREPARATION
SURFACE AREA
SURFACE PROPERTIES
COAL
COMBUSTION
FLUE GAS
DESULFURIZATION
FLY ASH
SULFUR DIOXIDE
REMOVAL
WATER
ADSORPTION
ADSORBENTS
CALCIUM CHLORIDES
CALCIUM NITRATES
CHEMICAL REACTION KINETICS
EQUILIBRIUM
FOSSIL-FUEL POWER PLANTS
GYPSUM
HUMIDITY
MOISTURE
SALTS
SLURRIES
AEROSOL WASTES
ALKALINE EARTH METAL COMPOUNDS
ASHES
CALCIUM COMPOUNDS
CALCIUM HALIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHLORIDES
CHLORINE COMPOUNDS
COMBUSTION PRODUCTS
DISPERSIONS
ENERGY SOURCES
FOSSIL FUELS
FUELS
GASEOUS WASTES
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
ISOTHERMS
KINETICS
MATERIALS
MINERALS
MIXTURES
NITRATES
NITROGEN COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
POWER PLANTS
REACTION KINETICS
RESIDUES
SILICATES
SILICON COMPOUNDS
SORPTION
SULFATE MINERALS
SULFUR COMPOUNDS
SULFUR OXIDES
SUSPENSIONS
SYNTHESIS
THERMAL POWER PLANTS
THERMOCHEMICAL PROCESSES
WASTES
010800* - Coal
Lignite
& Peat- Waste Management
010900 - Coal
Lignite
& Peat- Environmental Aspects
540120 - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)