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Title: Screening of low cost sorbents for arsenic and mercury capture in gasification systems

Abstract

A novel laboratory-scale fixed-bed reactor has been developed to investigate trace metal capture on selected sorbents for cleaning the hot raw gas in Integrated Gasification Combined Cycle (IGCC) power plants. The new reactor design is presented, together with initial results for mercury and arsenic capture on five sorbents. It was expected that the capture efficiency of sorbents would decrease with increasing temperature. However, a commercial activated carbon, Norit Darco 'Hg', and a pyrolysis char prepared from scrap tire rubber exhibit similar efficiencies for arsenic at 200 and at 400{sup o}C (70% and 50%, respectively). Meta-kaolinite and fly ash both exhibit an efficiency of around 50% at 200{sup o}C, which then dropped as the test temperature was increased to 400{sup o}C. Activated scrap tire char performed better at 200{sup o}C than the pyrolysis char showing an arsenic capture capacity similar to that of commercial Norit Darco 'Hg'; however, efficiency dropped to below 40% at 400{sup o}C. These results suggest that the capture mechanism of arsenic (As4) is more complex than purely physical adsorption onto the sorbents. Certain elements within the sorbents may have significant importance for chemical adsorption, in addition to the effect of surface area, as determined by the BETmore » method. This was indeed the case for the mercury capture efficiency for all four sorbents tested. Three of the sorbents tested retained 90% of the mercury when operated at 100{sup o}C. As the temperature increased, the efficiency of activated carbon and pyrolysis char reduced significantly. Curiously, despite having the smallest Brunauer-Emmet-Teller (BET) surface area, a pf-combustion ash was the most effective in capturing mercury over the temperature range studied. These observations suggest that the observed mercury capture was not purely physical adsorption but a combination of physical and chemical processes. 27 refs., 4 figs., 4 tabs.« less

Authors:
; ; ; ; ;  [1]
  1. Imperial College London, London (United Kingdom). Department of Chemical Engineering
Publication Date:
OSTI Identifier:
20961443
Resource Type:
Journal Article
Journal Name:
Energy and Fuels
Additional Journal Information:
Journal Volume: 21; Journal Issue: 5; Other Information: cedric.charpenteau@ic.ac.uk; Journal ID: ISSN 0887-0624
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; HOT GAS CLEANUP; ADSORBENTS; ARSENIC; MERCURY; COAL GASIFICATION; ACTIVATED CARBON; CHARS; KAOLINITE; FLY ASH; TIRES; CHEMISORPTION; WASTE PRODUCT UTILIZATION; FUEL GAS; TRACE AMOUNTS

Citation Formats

Charpenteau, Cedric, Seneviratne, Revata, George, Anthe, Millan, Marcos, Dugwell, Denis R, and Kandiyoti, Rafael. Screening of low cost sorbents for arsenic and mercury capture in gasification systems. United States: N. p., 2007. Web. doi:10.1021/ef070026c.
Charpenteau, Cedric, Seneviratne, Revata, George, Anthe, Millan, Marcos, Dugwell, Denis R, & Kandiyoti, Rafael. Screening of low cost sorbents for arsenic and mercury capture in gasification systems. United States. https://doi.org/10.1021/ef070026c
Charpenteau, Cedric, Seneviratne, Revata, George, Anthe, Millan, Marcos, Dugwell, Denis R, and Kandiyoti, Rafael. Sat . "Screening of low cost sorbents for arsenic and mercury capture in gasification systems". United States. https://doi.org/10.1021/ef070026c.
@article{osti_20961443,
title = {Screening of low cost sorbents for arsenic and mercury capture in gasification systems},
author = {Charpenteau, Cedric and Seneviratne, Revata and George, Anthe and Millan, Marcos and Dugwell, Denis R and Kandiyoti, Rafael},
abstractNote = {A novel laboratory-scale fixed-bed reactor has been developed to investigate trace metal capture on selected sorbents for cleaning the hot raw gas in Integrated Gasification Combined Cycle (IGCC) power plants. The new reactor design is presented, together with initial results for mercury and arsenic capture on five sorbents. It was expected that the capture efficiency of sorbents would decrease with increasing temperature. However, a commercial activated carbon, Norit Darco 'Hg', and a pyrolysis char prepared from scrap tire rubber exhibit similar efficiencies for arsenic at 200 and at 400{sup o}C (70% and 50%, respectively). Meta-kaolinite and fly ash both exhibit an efficiency of around 50% at 200{sup o}C, which then dropped as the test temperature was increased to 400{sup o}C. Activated scrap tire char performed better at 200{sup o}C than the pyrolysis char showing an arsenic capture capacity similar to that of commercial Norit Darco 'Hg'; however, efficiency dropped to below 40% at 400{sup o}C. These results suggest that the capture mechanism of arsenic (As4) is more complex than purely physical adsorption onto the sorbents. Certain elements within the sorbents may have significant importance for chemical adsorption, in addition to the effect of surface area, as determined by the BET method. This was indeed the case for the mercury capture efficiency for all four sorbents tested. Three of the sorbents tested retained 90% of the mercury when operated at 100{sup o}C. As the temperature increased, the efficiency of activated carbon and pyrolysis char reduced significantly. Curiously, despite having the smallest Brunauer-Emmet-Teller (BET) surface area, a pf-combustion ash was the most effective in capturing mercury over the temperature range studied. These observations suggest that the observed mercury capture was not purely physical adsorption but a combination of physical and chemical processes. 27 refs., 4 figs., 4 tabs.},
doi = {10.1021/ef070026c},
url = {https://www.osti.gov/biblio/20961443}, journal = {Energy and Fuels},
issn = {0887-0624},
number = 5,
volume = 21,
place = {United States},
year = {2007},
month = {9}
}