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Sulfur and Chlorine Gas Species Formation during Coal Pyrolysis in Nitrogen and Carbon Dioxide Atmosphere

Frigge, Lorenz and Elserafi, Ghada and Ströhle, Jochen and Epple, Bernd (2016):
Sulfur and Chlorine Gas Species Formation during Coal Pyrolysis in Nitrogen and Carbon Dioxide Atmosphere.
In: Energy & Fuels, pp. 7713-7720, 30, (9), ISSN 0887-0624,
DOI: 10.1021/acs.energyfuels.6b01080,
[Online-Edition: https://doi.org/10.1021/acs.energyfuels.6b01080],
[Article]

Abstract

Coal combustion in CO2/O2 (oxy-fuel combustion) allows reducing fossil carbon dioxide emissions in the atmosphere. The change of oxidizer from N2/O2 (air) to CO2/O2 changes the combustion process, including pyrolysis. The formation of sulfur and chlorine species during temperature-programmed coal pyrolysis in N2 and CO2 atmosphere and with heating rates of 10 and 20 K/min was studied. Two high volatile bituminous coals with different sulfur content but almost identical relative distribution of sulfur species (sulfide, pyritic, sulfate, and organic) were used in the experiments. The release of H2S, SO2, COS, and HCl was determined using mass spectrometry. Two and three peaks were observed in the hydrogen sulfide and sulfur dioxide release profiles, respectively, which are caused by the different sulfur species present in the coals. It was found that the release profile of sulfur dioxide varies for the coals, which means that information about sulfur forms is not sufficient to predict SO2 formation during pyrolysis. While the release rate of hydrogen sulfide and sulfur dioxide was either similar or lower in the presence of CO2 when compared to pyrolysis in N2, formation of carbonyl sulfide was only detected in CO2 atmosphere. For hydrogen chloride, two distinct release temperature ranges were identified. The predominant HCl formation occurred at temperatures ranging from 300 to 500 °C and was reduced by changing from N2 to CO2 atmosphere. The fate of sulfur and chlorine during pyrolysis of the two coals is very different although both coals are very similar regarding sulfur species distribution.

Item Type: Article
Erschienen: 2016
Creators: Frigge, Lorenz and Elserafi, Ghada and Ströhle, Jochen and Epple, Bernd
Title: Sulfur and Chlorine Gas Species Formation during Coal Pyrolysis in Nitrogen and Carbon Dioxide Atmosphere
Language: English
Abstract:

Coal combustion in CO2/O2 (oxy-fuel combustion) allows reducing fossil carbon dioxide emissions in the atmosphere. The change of oxidizer from N2/O2 (air) to CO2/O2 changes the combustion process, including pyrolysis. The formation of sulfur and chlorine species during temperature-programmed coal pyrolysis in N2 and CO2 atmosphere and with heating rates of 10 and 20 K/min was studied. Two high volatile bituminous coals with different sulfur content but almost identical relative distribution of sulfur species (sulfide, pyritic, sulfate, and organic) were used in the experiments. The release of H2S, SO2, COS, and HCl was determined using mass spectrometry. Two and three peaks were observed in the hydrogen sulfide and sulfur dioxide release profiles, respectively, which are caused by the different sulfur species present in the coals. It was found that the release profile of sulfur dioxide varies for the coals, which means that information about sulfur forms is not sufficient to predict SO2 formation during pyrolysis. While the release rate of hydrogen sulfide and sulfur dioxide was either similar or lower in the presence of CO2 when compared to pyrolysis in N2, formation of carbonyl sulfide was only detected in CO2 atmosphere. For hydrogen chloride, two distinct release temperature ranges were identified. The predominant HCl formation occurred at temperatures ranging from 300 to 500 °C and was reduced by changing from N2 to CO2 atmosphere. The fate of sulfur and chlorine during pyrolysis of the two coals is very different although both coals are very similar regarding sulfur species distribution.

Journal or Publication Title: Energy & Fuels
Volume: 30
Number: 9
Divisions: 16 Department of Mechanical Engineering
16 Department of Mechanical Engineering > Institut für Energiesysteme und Energietechnik (EST)
16 Department of Mechanical Engineering > Institute of Production Management, Technology and Machine Tools (PTW)
16 Department of Mechanical Engineering > Institute of Production Management, Technology and Machine Tools (PTW) > ETA Energy Technologies and Applications in Production
Date Deposited: 30 Jan 2018 14:05
DOI: 10.1021/acs.energyfuels.6b01080
Official URL: https://doi.org/10.1021/acs.energyfuels.6b01080
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