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Method for the control of NOx emissions in long-range space travelThe wheat straw, an inedible biomass that can be continuously produced in a space vehicle has been used to produce activated carbon for effective control of NOx emissions from the incineration of wastes. The optimal carbonization temperature of wheat straw was found to be around 600 degrees C when a burnoff of 67% was observed. The BET surface area of the activated carbon produced from the wheat straw reached as high as 300 m2/g. The presence of oxygen in flue gas is essential for effective adsorption of NO by activated carbon. On the contrary, water vapor inhibits the adsorption efficiency of NO. Consequently, water vapor in flue gas should be removed by drying agents before adsorption to ensure high NO adsorption efficiency. All of the NO in the flue gas was removed for more than 2 h by the activated carbons when 10% oxygen was present and the ratio of carbon weight to the flue gas flow rate (W/F) was 30 g min/L, with a contact time of 10.2 s. All of NO was reduced to N2 by the activated carbon at 450 degrees C with a W/F ratio of 15 g min/L and a contact time of 5.1 s. Reduction of the adsorbed NO also regenerated the activated carbon, and the regenerated activated carbon exhibited an improved NO adsorption efficiency. However, the reduction of the adsorbed NO resulted in a loss of carbon which was determined to be about 0.99% of the activated carbon per cycle of regeneration. The sufficiency of the amount of wheat straw in providing the activated carbon based on a six-person crew, such as the mission planned for Mars, has been determined. This novel approach for the control of NOx emissions is sustainable in a closed system such as the case in space travel. It is simple to operate and is functional under microgravity environment.
Document ID
20040087440
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Xu, X. H.
(Lawrence Berkeley National Laboratory, University of California Berkeley, California 94720, United States)
Shi, Y.
Liu, S. H.
Wang, H. P.
Chang, S. G.
Fisher, J. W.
Pisharody, S.
Moran, M.
Wignarajah, K.
Date Acquired
August 21, 2013
Publication Date
September 1, 2003
Publication Information
Publication: Energy & fuels : an American Chemical Society journal
Volume: 17
Issue: 5
ISSN: 0887-0624
Subject Category
Man/System Technology And Life Support
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Life Support Systems
NASA Program Advanced Human Support Technology
NASA Center ARC

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