Control of ash deposition through the high temperature adsorption of alkali vapors on solid sorbents

Conference · Sun Jan 01 00:00:00 EST 1989 · Preprints of Papers, American Chemical Society, Division of Fuel Chemistry; (USA)

OSTI ID:5114558

Punjak, W A; Uberoi, M; Shadman, F ^[1]

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1. Univ. of Arizona, Tucson (USA)

Coal usually contains sodium and potassium minerals in various chemical and physical forms. During the combustion or gasification of coal, much of this alkali is released into the gas phase. This vapor is usually in the form of alkali chlorides. In the presence of sulfur, alkali sulfates are also formed. This alkali condenses on and reacts with ash to form low melting point phases that enhance fouling. Cleaning of coal removes some of the alkali but is not effective enough to decrease the alkali concentration to acceptable levels. A promising technique for the removal of alkali from hot flue gases is by using materials (sorbents) that will adsorb and/or react with alkali vapors. In general, the sorbents can be used in two ways. One method is by passing the alkali-laden flue gas through a fixed bed of an appropriate sorbent. This process has been considered for alkali removal from flue gases in the combined-cycle power generation from coal. The second method is the injection of sorbents with coal for the in-situ capturing of alkali during pulverized coal combustion. This method has received much less attention. The choice of a suitable sorbent depends on the coal properties and the process operating conditions. In general, however, the important characteristics desired in a potential sorbent are high temperature compatibility, rapid rate of adsorption, high loading capacity, transformation of the alkali into a less corrosive form and irreversible adsorption to prevent the release of adsorbed alkali during process fluctuations. Previous studies in this laboratory and those of other investigators have suggested that bauxite, kaolinite and emathlite are promising alkali vapor sorbents. The purpose of this study is to obtain fundamental information on the kinetics and the mechanism of alkali adsorption on these sorbents.

• OSTI ID: 5114558
• Report Number(s): CONF-8904166-; CODEN: ACFPA
• Journal Information: Preprints of Papers, American Chemical Society, Division of Fuel Chemistry; (USA), Vol. 34:2; Conference: Symposium on ash deposition: mineral matter deposition phenomena, formation and control, Dallas, TX (USA), 9-14 Apr 1989; ISSN 0569-3772
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
BAUXITE
SORPTIVE PROPERTIES
COAL
COMBUSTION
FLY ASH
DEPOSITION
KAOLINITE
POTASSIUM COMPOUNDS
ADSORPTION
SODIUM COMPOUNDS
CHEMICAL REACTION KINETICS
DEPOSITS
EXPERIMENTAL DATA
HIGH TEMPERATURE
VAPORS
AEROSOL WASTES
ALKALI METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM ORES
ALUMINIUM SILICATES
ASHES
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
DATA
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUELS
GASES
INFORMATION
KINETICS
MATERIALS
MINERALS
NUMERICAL DATA
ORES
OXIDATION
OXYGEN COMPOUNDS
REACTION KINETICS
RESIDUES
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SORPTION
SURFACE PROPERTIES
THERMOCHEMICAL PROCESSES
WASTES
010600* - Coal
Lignite
& Peat- Properties & Composition
010800 - Coal
Lignite
& Peat- Waste Management
010404 - Coal
Lignite
& Peat- Gasification
010409 - Coal
Lignite
& Peat- Pyrolysis & Carbonization- (1987-)