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Title: Diatomaceous earth and activated bauxite used as granular sorbents for the removal of sodium chloride vapor from hot flue gas

Abstract

Diatomaceous earth and activated bauxite were tested as granular sorbents for use as filter media in granular-bed filters for the removal of gaseous alkali metal compounds from the hot (800/sup 0/C) flue gas of PFBC. Tests were performed at atmospheric pressure, using NaCl vapor transported in relatively dry simulated flue gas of PFBC. Either a fixed-bed combustor or a high-temperature sorption test rig was used. The effects of sorbent bed temperature, superficial gas velocity, gas hourly space velocity, and NaCl-vapor concentration in flue gas on the sorption behavior of these two sorbents and their ultimate sorption capacities were determined. Both diatomaceous earth and activated bauxite were found to be very effective in removing NaCl vapor from flue gas. Preliminary cost evaluations showed that they are economically attractive as granular sorbents for cleaning alkali vapor from simulated flue gas.

Authors:
; ;
Publication Date:
Research Org.:
Argonne National Lab., IL (USA)
OSTI Identifier:
5657303
Report Number(s):
ANL/CEN/FE-79-18
DOE Contract Number:
W-31-109-ENG-38
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; 42 ENGINEERING; ALKALI METAL COMPOUNDS; REMOVAL; BAUXITE; DIATOMACEOUS EARTH; SORPTIVE PROPERTIES; HOT GAS CLEANUP; GRANULAR BED FILTERS; COAL; FLUE GAS; FLUIDIZED-BED COMBUSTION; MEDIUM PRESSURE; ALUMINIUM ORES; CARBONACEOUS MATERIALS; CHEMICAL REACTIONS; COMBUSTION; ENERGY SOURCES; FILTERS; FOSSIL FUELS; FUELS; GASEOUS WASTES; MECHANICAL FILTERS; MINERALS; ORES; OXIDATION; PURIFICATION; SURFACE PROPERTIES; THERMOCHEMICAL PROCESSES; WASTES; 010800* - Coal, Lignite, & Peat- Waste Management; 421000 - Engineering- Combustion Systems; 014000 - Coal, Lignite, & Peat- Combustion

Citation Formats

Lee, S.H.D., Swift, W.M., and Johnson, I. Diatomaceous earth and activated bauxite used as granular sorbents for the removal of sodium chloride vapor from hot flue gas. United States: N. p., 1980. Web. doi:10.2172/5657303.
Lee, S.H.D., Swift, W.M., & Johnson, I. Diatomaceous earth and activated bauxite used as granular sorbents for the removal of sodium chloride vapor from hot flue gas. United States. doi:10.2172/5657303.
Lee, S.H.D., Swift, W.M., and Johnson, I. 1980. "Diatomaceous earth and activated bauxite used as granular sorbents for the removal of sodium chloride vapor from hot flue gas". United States. doi:10.2172/5657303. https://www.osti.gov/servlets/purl/5657303.
@article{osti_5657303,
title = {Diatomaceous earth and activated bauxite used as granular sorbents for the removal of sodium chloride vapor from hot flue gas},
author = {Lee, S.H.D. and Swift, W.M. and Johnson, I.},
abstractNote = {Diatomaceous earth and activated bauxite were tested as granular sorbents for use as filter media in granular-bed filters for the removal of gaseous alkali metal compounds from the hot (800/sup 0/C) flue gas of PFBC. Tests were performed at atmospheric pressure, using NaCl vapor transported in relatively dry simulated flue gas of PFBC. Either a fixed-bed combustor or a high-temperature sorption test rig was used. The effects of sorbent bed temperature, superficial gas velocity, gas hourly space velocity, and NaCl-vapor concentration in flue gas on the sorption behavior of these two sorbents and their ultimate sorption capacities were determined. Both diatomaceous earth and activated bauxite were found to be very effective in removing NaCl vapor from flue gas. Preliminary cost evaluations showed that they are economically attractive as granular sorbents for cleaning alkali vapor from simulated flue gas.},
doi = {10.2172/5657303},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1980,
month = 1
}

Technical Report:

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  • Regeneration of activated bauxite was studied by water-leaching and thermal swing (high-temperature desorption) methods. Granular activated bauxite has been identified to be very effective when used as a filter medium (i.e., sorbent) in granular-bed filters to remove gaseous alkali metal compounds from simulated hot flue gas of PFBC. Activated bauxite that had captured alkali chloride vapors was demonstrated to be easily and effectively regenerated for reuse by a simple water-leaching method. Data were obtained on (1) the leaching rate of the adsorbed NaCl, (2) effects on the leaching rate of adsorbed NaCl loading, leaching temperature, and the amount of water,more » and (3) water retention in activated bauxite after leaching. Observed physical changes and particle attrition of activated bauxite as a result of regeneration are discussed. The sorption mechanisms of activated bauxite toward alkali chloride vapors are interpreted on the basis of (1) the chemical compositions of the leachates from alkali chloride-sorbed activated bauxite and (2) the desorption of adsorbed NaCl vapor from activated bauxite at high temperature.« less
  • This work supports the program to develop methods for the cleanup of combustion gases from pressurized fluidized-bed coal combustors so that the cleaned gases can be used to power downstream gas turbines. Presented here are the results of studies to develop granular sorbents for removing gaseous alkali metal compounds from these combustion gases in a granular-bed filter. Activated bauxite bed material can be reused after the alkali compound is removed by a water-leaching process. In experiments to study the kinetics of leaching, the effects of adsorbed NaCl loading, leaching temperature, and the leaching water to sorbent ratio on the ratemore » of leaching are reported. Also reported are water retention in bauxite after leaching and the effect of volatile alkalis in makeup activated bauxite on the alkali level in flue gas expanded in the gas turbine.« less
  • Six commercially available sorbent materials have been tested as granular sorbents to be used in granular-bed filters for the removal of gaseous alkali metal compounds from the hot (800 to 880/sup 0/C) flue gas of pressurized fluidized-bed combustors (PFBC) for proposed combined-cycle power generation. Tests were performed by passing simulated relatively dry flue gas of PFBC through granular-bed filters in either a laboratory-scale, fixed-bed combustor or a high temperature sorption test rig. The experimental results of screening tests are presented. Diatomaceous earth and activated bauxite were found to be the two most promising sorbents. Possible sorption mechanisms and applications ofmore » the sorbents are discussed. 3 figures, 7 tables.« less
  • The study reveals that radium adsorption onto precipitated MnO2 followed by diatomaceous earth (DE) filtration is a very effective treatment process for radium-contaminated water. Radium removals in the range of 80% to 97% were observed for performed MnO2 feed concentrations of 0.63 and 1.26 mg/L as Mn in groundwaters with hardness in the range of 100 to 245 mg/L as CaCO3. Radium removal increased slightly with increasing pH whereas it decreased slightly with increasing hardness and iron (II) concentrations. Pilot studies were performed in Lemont, IL using DE filtration on a groundwater containing 12 pCi/L226Ra and 6 pCi/L228. Radium removalsmore » for both the pilot plants ranged from 90% to 97% at a MnO2 feed concentration of 1.26 mg/L as Mn, a total hardness of 245 mg/L as CaCO3, and a pH of 6.5. The costs of water treatment by MnO2 adsorption and DE filtration were estimated at $0.71 per 1000 gal for 280,000 gpd plants and $0.47 for 1 Mgd plants.« less
  • A fixed granular-bed sorber, with regenerable activated bauxite as the sorbent, for the control of the alkali vapor in the flue gas produced during pressurized fluidized-bed combustion (PFBC) of coal is being developed. In a gas stream closely simulating the actual PFBC flue gas, activated bauxite is shown to capture NaCl vapor by (1) chemical fixation of the vapor with the intrinsic clay minerals, probably to form thermally stable, water-insoluble sodium aluminosilicates and (2) chemical conversion of NaCl vapor into a condensed-phase sodium sulfate, which has a much lower vapor pressure than does NaCl. The latter predominates the capture process,more » and the captured sodium sulfate can be easily removed by simple water-leaching to restore the porosity of activated bauxite for reuse. A high-temperature (less than or equal to 900/sup 0/C) and high-pressure (less than or equal to 10 atm) laboratory-scale, fixed, granular-bed alkali sorber has been operated with the Argonne National Laboratory PFBC combustor to (1) measure the alkali vapor concentration in the PFBC flue gas on a real-time, on-line basis, and (2) demonstrate the alkali sorber for the control of alkali vapor from an actual PFBC flue gas. The alkali (Na + K) vapor concentration in particulate filtered hot flue gas was measured to be <10 ppbW with the Ames analyzer. The same measurement with the APST was higher between 90 to 170 ppbW. Therefore, the possibility of sink for sodium vapor in the PFBC/alkali sorber system must be considered. 32 refs.« less