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Title: Membrane Processes for the Sulfur-Iodine Thermochemical Cycle

Abstract

Removal of water from aqueous hydriodic acid (HI) by pervaporation using Nafion-117® membranes has been studied. In this work, Nafion membranes have been used to separate water from HI at concentrations from 18 to 70 % and at temperatures ranging from 22 °C to 109 °C. Initial fluxes of the more dilute acid solutions were as high as 1500 g/m2h with a separation factor (á) of 139. Furthermore, separation factors as high as 500-700 were obtained for more concentrated samples. In general, increased temperatures yielded higher fluxes with lower separation factors and higher feed concentrations gave lower fluxes with higher separation factors. Activation energies of transport (EJ) values have been calculated for lower and higher concentration HI feeds and compared to pure water pervaporation. These data suggest that the degree of protonation and mole fraction water in the feed influence transport kinetics and that boundary layers issues become more prevalent at higher HI concentrations. Additionally, initial data using a sweep gas in place of the vacuum permeate trapping system was shown to provide similar flux magnitudes as the vacuum system providing versatility for potential plant applications.

Authors:
; ;
Publication Date:
Research Org.:
Idaho National Laboratory (INL)
Sponsoring Org.:
DOE - NE
OSTI Identifier:
912360
Report Number(s):
INL/JOU-05-00523
Journal ID: ISSN 0360-3199; IJHEDX; TRN: US200801%%794
DOE Contract Number:
DE-AC07-99ID-13727
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Hydrogen Energy; Journal Volume: 32; Journal Issue: 4
Country of Publication:
United States
Language:
English
Subject:
08 - HYDROGEN; BOUNDARY LAYERS; HYDRIODIC ACID; KINETICS; MEMBRANES; REMOVAL; TRANSPORT; TRAPPING; VACUUM SYSTEMS; WATER

Citation Formats

Frederick F. Stewart, Christopher J. Orme, and Michael G. Jones. Membrane Processes for the Sulfur-Iodine Thermochemical Cycle. United States: N. p., 2007. Web. doi:10.1016/j.ijhydene.2006.06.055.
Frederick F. Stewart, Christopher J. Orme, & Michael G. Jones. Membrane Processes for the Sulfur-Iodine Thermochemical Cycle. United States. doi:10.1016/j.ijhydene.2006.06.055.
Frederick F. Stewart, Christopher J. Orme, and Michael G. Jones. Thu . "Membrane Processes for the Sulfur-Iodine Thermochemical Cycle". United States. doi:10.1016/j.ijhydene.2006.06.055.
@article{osti_912360,
title = {Membrane Processes for the Sulfur-Iodine Thermochemical Cycle},
author = {Frederick F. Stewart and Christopher J. Orme and Michael G. Jones},
abstractNote = {Removal of water from aqueous hydriodic acid (HI) by pervaporation using Nafion-117® membranes has been studied. In this work, Nafion membranes have been used to separate water from HI at concentrations from 18 to 70 % and at temperatures ranging from 22 °C to 109 °C. Initial fluxes of the more dilute acid solutions were as high as 1500 g/m2h with a separation factor (á) of 139. Furthermore, separation factors as high as 500-700 were obtained for more concentrated samples. In general, increased temperatures yielded higher fluxes with lower separation factors and higher feed concentrations gave lower fluxes with higher separation factors. Activation energies of transport (EJ) values have been calculated for lower and higher concentration HI feeds and compared to pure water pervaporation. These data suggest that the degree of protonation and mole fraction water in the feed influence transport kinetics and that boundary layers issues become more prevalent at higher HI concentrations. Additionally, initial data using a sweep gas in place of the vacuum permeate trapping system was shown to provide similar flux magnitudes as the vacuum system providing versatility for potential plant applications.},
doi = {10.1016/j.ijhydene.2006.06.055},
journal = {International Journal of Hydrogen Energy},
number = 4,
volume = 32,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}