Evaluation of flow fields on bubble removal and system performance in an ammonium bicarbonate reverse electrodialysis stack

Handle URI:
http://hdl.handle.net/10754/598247
Title:
Evaluation of flow fields on bubble removal and system performance in an ammonium bicarbonate reverse electrodialysis stack
Authors:
Hatzell, Marta C.; Logan, Bruce E.
Abstract:
Ammonium bicarbonate has recently been demonstrated to be an excellent thermolytic solution for energy generation in reverse electrodialysis (RED) stacks. However, operating RED stacks at room temperatures can promote gaseous bubble (CO2, NH3) accumulation within the stack, reducing overall system performance. The management and minimization of bubbles formed in RED flow fields is an important operational issue which has yet to be addressed. Flow fields with and without spacers in RED stacks were analyzed to determine how both fluid flow and the buildup and removal of bubbles affected performance. In the presence of a spacer, the membrane resistance increased by ~50Ω, resulting in a decrease in power density by 30% from 0.140Wm-2 to 0.093Wm-2. Shorter channels reduced concentration polarization affects, and resulted in 3-23% higher limiting current density. Gas accumulation was minimized through the use of short vertically aligned channels, and consequently the amount of the membrane area covered by bubbles was reduced from ~20% to 7% which caused a 12% increase in power density. As ammonium bicarbonate RED systems are scaled up, attention to channel aspect ratio, length, and alignment will enable more stable performance. © 2013 Elsevier B.V.
Citation:
Hatzell MC, Logan BE (2013) Evaluation of flow fields on bubble removal and system performance in an ammonium bicarbonate reverse electrodialysis stack. Journal of Membrane Science 446: 449–455. Available: http://dx.doi.org/10.1016/j.memsci.2013.06.019.
Publisher:
Elsevier BV
Journal:
Journal of Membrane Science
KAUST Grant Number:
KUS-I1-003-13
Issue Date:
Nov-2013
DOI:
10.1016/j.memsci.2013.06.019
Type:
Article
ISSN:
0376-7388
Sponsors:
This research was supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. (DGE0750756) and a grant from the King Abdullah University of Science and Technology (KAUST) (Award KUS-I1-003-13).
Appears in Collections:
Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorHatzell, Marta C.en
dc.contributor.authorLogan, Bruce E.en
dc.date.accessioned2016-02-25T13:17:20Zen
dc.date.available2016-02-25T13:17:20Zen
dc.date.issued2013-11en
dc.identifier.citationHatzell MC, Logan BE (2013) Evaluation of flow fields on bubble removal and system performance in an ammonium bicarbonate reverse electrodialysis stack. Journal of Membrane Science 446: 449–455. Available: http://dx.doi.org/10.1016/j.memsci.2013.06.019.en
dc.identifier.issn0376-7388en
dc.identifier.doi10.1016/j.memsci.2013.06.019en
dc.identifier.urihttp://hdl.handle.net/10754/598247en
dc.description.abstractAmmonium bicarbonate has recently been demonstrated to be an excellent thermolytic solution for energy generation in reverse electrodialysis (RED) stacks. However, operating RED stacks at room temperatures can promote gaseous bubble (CO2, NH3) accumulation within the stack, reducing overall system performance. The management and minimization of bubbles formed in RED flow fields is an important operational issue which has yet to be addressed. Flow fields with and without spacers in RED stacks were analyzed to determine how both fluid flow and the buildup and removal of bubbles affected performance. In the presence of a spacer, the membrane resistance increased by ~50Ω, resulting in a decrease in power density by 30% from 0.140Wm-2 to 0.093Wm-2. Shorter channels reduced concentration polarization affects, and resulted in 3-23% higher limiting current density. Gas accumulation was minimized through the use of short vertically aligned channels, and consequently the amount of the membrane area covered by bubbles was reduced from ~20% to 7% which caused a 12% increase in power density. As ammonium bicarbonate RED systems are scaled up, attention to channel aspect ratio, length, and alignment will enable more stable performance. © 2013 Elsevier B.V.en
dc.description.sponsorshipThis research was supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. (DGE0750756) and a grant from the King Abdullah University of Science and Technology (KAUST) (Award KUS-I1-003-13).en
dc.publisherElsevier BVen
dc.subjectDiffusion boundary layer resistanceen
dc.subjectElectrochemical impedance spectroscopyen
dc.subjectFluid flow field designen
dc.subjectGas managementen
dc.subjectReverse electrodialysisen
dc.titleEvaluation of flow fields on bubble removal and system performance in an ammonium bicarbonate reverse electrodialysis stacken
dc.typeArticleen
dc.identifier.journalJournal of Membrane Scienceen
dc.contributor.institutionPennsylvania State University, State College, United Statesen
kaust.grant.numberKUS-I1-003-13en
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