elib
DLR-Header
DLR-Logo -> http://www.dlr.de
DLR Portal Home | Imprint | Privacy Policy | Contact | Deutsch
Fontsize: [-] Text [+]

Electrochemical Method for Monitoring Corrosive Impurities in Molten MgCl2/KCl/NaCl Salts for Thermal Energy Storage

Ding, Wenjin and Bonk, Alexander and Joachim, Gussone and Thomas, Bauer (2017) Electrochemical Method for Monitoring Corrosive Impurities in Molten MgCl2/KCl/NaCl Salts for Thermal Energy Storage. 11th International Renewable Energy Storage Conference (IRES 2017), 14-16. March 2017, Düsseldorf, Germany.

Full text not available from this repository.

Abstract

Molten chloride salt mixtures are promising thermal energy storage (TES) materials to be applied in concentrating solar power (CSP) plants, due to their physicochemical and thermal properties. Their high thermal stability makes them appropriate candidates to replace the commercial TES materials in CSP, nitrate salt mixtures (stable up to 550 °C), when higher operating temperatures are required (up to 700 °C) for higher efficiency of thermal to electrical energy conversion. However, the application of molten chloride salts at higher temperatures causes additional challenges, particularly increased corrosiveness of containers and structural materials. It is well known that the corrosion rates significantly depend on the concentration of oxide/hydroxide impurities in the molten chloride salts. In this work, an electrochemical analysis system based on cyclic voltammetry (CV) is being developed to measure the concentration of these impurities in-situ, in order to assist the corrosion control on the molten salts. Before the electrochemical experiments, pre-electrolysis (PE) was performed on the studied molten MgCl2/KCl/NaCl (60/20/20 mole%) salts to remove most of the impurities including oxide/hydroxide. By fitting the CV data from PE with those from the acid consumption measurements on the simultaneously collected salt samples, the constant for the calculation of the concentration of MgOH+ from the current density under the conditions 500 °C and sweep rate of 200 mV/s was determined. After PE, by adding NaOH pellets into the molten salts, a significant change of a peak in the cathodic potential range of the cyclic voltammogram was observed. This is considered to be caused by the change of the concentration of the stable hydroxide species (MgOH+) according to literature. When the determined constant based on the CV data from PE experiments was used in the calculation of the concentrations of MgOH+ from the current density of the peak for the reduction reaction of MgOH+, the concentrations of MgOH+ determined from titration compare well with those from the CV experiments.

Item URL in elib:https://elib.dlr.de/112540/
Document Type:Conference or Workshop Item (Poster)
Title:Electrochemical Method for Monitoring Corrosive Impurities in Molten MgCl2/KCl/NaCl Salts for Thermal Energy Storage
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Ding, WenjinInstitute of Engineering Thermodynamics, Thermal Process Technology, wenjin.ding (at) dlr.deUNSPECIFIED
Bonk, AlexanderInstitute of Engineering Thermodynamics, Thermal Process TechnologyUNSPECIFIED
Joachim, GussoneInstitute of Materials ResearchUNSPECIFIED
Thomas, BauerInstitute of Engineering Thermodynamics, Thermal Process TechnologyUNSPECIFIED
Date:14 March 2017
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:Corrosion, Cyclic voltammetry (CV), Concentrating solar power plant (CSP), Magnesium hydroxyl ion (MgOH+), In-situ concentration measurement.
Event Title:11th International Renewable Energy Storage Conference (IRES 2017)
Event Location:Düsseldorf, Germany
Event Type:international Conference
Event Dates:14-16. March 2017
Organizer:EUROSOLAR e.V.
HGF - Research field:Energy
HGF - Program:Storage and Cross-linked Infrastructures
HGF - Program Themes:Thermal Energy Storage
DLR - Research area:Energy
DLR - Program:E SP - Energy Storage
DLR - Research theme (Project):E - Thermochemical Processes (Storage)
Location: Stuttgart
Institutes and Institutions:Institute of Engineering Thermodynamics > Thermal Process Technology
Deposited By: Ding, Wenjin
Deposited On:26 Jun 2017 10:57
Last Modified:17 Jan 2018 16:10

Repository Staff Only: item control page

Browse
Search
Help & Contact
Information
electronic library is running on EPrints 3.3.12
Copyright © 2008-2017 German Aerospace Center (DLR). All rights reserved.