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Effect of pressure and impurities on oxidation in supercritical CO 2
Author(s) -
Pint Bruce A.,
Lehmusto Juho,
Lance Michael J.,
Keiser James R.
Publication year - 2019
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201810652
Subject(s) - impurity , supercritical fluid , materials science , oxide , chemical engineering , analytical chemistry (journal) , chemistry , metallurgy , chromatography , organic chemistry , engineering
Both indirect‐ and direct‐fired supercritical CO 2 cycles for high‐efficiency power generation are expected to have impurities that may greatly alter the compatibility of Fe‐ and Ni‐based structural alloys in these environments. Recent work has attempted to quantify reaction rates at 750°C in simulated laboratory environments with controlled impurity levels at ambient pressure, as well as under supercritical conditions (30 MPa). With low impurity levels in research and industrial‐grade CO 2 , pressure appeared to have only a limited effect on oxide thickness and internal oxidation and reaction products were similar to those formed in laboratory air. However, a direct‐fired simulation at 750°C/30 MPa in CO 2 + 1%O 2 + 0.25%H 2 O has found an increased mass gain and characterization after 2,500‐hr exposures have found thicker reaction products, especially for Fe‐based alloys. At these impurity levels, pressure may have a significant effect on the role of impurities.