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Title: A fixed granular-bed sorber for measurement and control of alkali vapors in PFBC (pressurized fluidized-bed combustion)

Alkali vapors (Na and K) in the hot flue gas from the pressurized fluidized-bed combustion (PFBC) of coal could cause corrosion problems with the gas turbine blades. In a laboratory-scale PFBC test with Beulah lignite, a fixed granular bed of activated bauxite sorbent was used to demonstrate its capability for measuring and controlling alkali vapors in the PFBC flue gas. The Beulah lignite was combusted in a bed of Tymochtee dolomite at bed temperatures ranging from 850 to 875{degrees}C and a system pressure of 9.2 atm absolute. The time-averaged concentration of sodium vapor in the PFBC flue gas was determined from the analysis of two identical beds of activated bauxite and found to be 1.42 and 1.50 ppmW. The potassium vapor concentration was determined to be 0.10 ppmW. The sodium material balance showed that only 0.24% of the total sodium in the lignite was released as vapor species in the PFBC flue gas. This results in an average of 1.56 ppmW alkali vapors in the PFBC flue gas. This average is more than 1.5 orders of magnitude greater than the currently suggested alkali specification limit of 0.024 ppm for an industrial gas turbine. The adsorption data obtained with the activatedmore » bauxite beds were also analyzed mathematically by use of a LUB (length of unused bed)/equilibrium section concept. Analytical results showed that the length of the bed, L{sub o} in centimeters, relates to the break through time, {theta}{sub b} in hours, for the alkali vapor to break through the bed as follows: L{sub o} = 33.02 + 1.99 {theta}{sub b}. This formula provides useful information for the engineering design of fixed-bed activated bauxite sorbers for the measurement and control of alkali vapors in PFBC flue gas. 26 refs., 4 figs., 4 tabs.« less
Authors:
;
Publication Date:
OSTI Identifier:
6154760
Report Number(s):
ANL/CP-71607; CONF-910424--1
ON: DE91004439
DOE Contract Number:
W-31109-ENG-38
Resource Type:
Conference
Resource Relation:
Conference: 11. international conference on fluidized bed combustion, Montreal (Canada), 21-24 Apr 1991
Research Org:
Argonne National Lab., IL (USA)
Sponsoring Org:
DOE/FE
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; FLUIDIZED-BED COMBUSTORS; GRANULAR BED FILTERS; PERFORMANCE; POTASSIUM; ADSORPTION; SODIUM; BAUXITE; CHEMICAL PROPERTIES; CLEANING; COAL-FIRED GAS TURBINES; CORROSION; DIMENSIONS; DOLOMITE; EROSION; EXHAUST GASES; FLOWSHEETS; FLUIDIZED-BED COMBUSTION; LIGNITE; MATERIAL BALANCE; MATHEMATICAL MODELS; PRESSURIZATION; REMOVAL; SORPTIVE PROPERTIES; TIME DEPENDENCE; TURBINE BLADES; VAPORS; ALKALI METALS; ALKALINE EARTH METAL COMPOUNDS; ALUMINIUM ORES; BROWN COAL; CALCIUM CARBONATES; CALCIUM COMPOUNDS; CARBON COMPOUNDS; CARBONACEOUS MATERIALS; CARBONATE MINERALS; CARBONATES; CHEMICAL REACTIONS; COAL; COMBUSTION; COMBUSTORS; DIAGRAMS; ELEMENTS; ENERGY SOURCES; FILTERS; FLUIDS; FOSSIL FUELS; FUELS; GAS TURBINES; GASEOUS WASTES; GASES; MACHINERY; MAGNESIUM CARBONATES; MAGNESIUM COMPOUNDS; MATERIALS; MECHANICAL FILTERS; METALS; MINERALS; ORES; OXIDATION; OXYGEN COMPOUNDS; SORPTION; SURFACE PROPERTIES; THERMOCHEMICAL PROCESSES; TURBINES; TURBOMACHINERY; WASTES 010402* -- Coal, Lignite, & Peat-- Purification & Upgrading