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Evaluation of dopants in hydrogen to reduce hydrogen permeation in candidate Stirling engine heater head tube alloys at 760 deg and 820 degAlloy tubes filled with hydrogen doped with various amounts of carbon monoxide, carbon dioxide, ethane, ethylene, methane, ammonia, or water were heated in a diesel fuel-fired Stirling engine simulator materials test rig for 100 hours at 21 MPa and 760 or 820 C to determine the effectiveness of the dopants in reducing hydrogen permeation through the hot tube walls. Ultra high purity (UHP) hydrogen was used for comparison. The tube alloys were N-155, A-286, Incoloy 800, Nitronic 40, 19-9DL, 316 stainless steel, Inconel 718, and HS-188. Carbon dioxide and carbon monoxide in the concentration range 0.2 to 5 vol % were most effective in reducing hydrogen permeation through the hot tube walls for all alloys. Ethane, ethylene, methane, ammonia, and water at the concentrations investigated were not effective in reducing the permeation below that achieved with UHP hydrogen. One series of tests were conducted with UHP hydrogen in carburized tubes. Carburization of the tubes prior to exposure reduced permeation to values similar to those for carbon monoxide; however, carbon dioxide was the most effective dopant.
Document ID
19830004961
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Misencik, J. A.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 4, 2013
Publication Date
October 1, 1982
Subject Category
Metallic Materials
Report/Patent Number
DOE/NASA/51040-41
R-1309
NASA-TM-82920
NAS 1.15:82920
Accession Number
83N13232
Funding Number(s)
CONTRACT_GRANT: DE-AI01-77CS-51040
PROJECT: RTOP 778-35-03
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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