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Theoretical Analysis of the Electrochemistry and Power Generation in Thermally Activated Batteries
, M.Sc. Thesis Sharif University of Technology ; Gobal, Fereydoun (Supervisor)
Abstract
Study the potential and internal resistance of the electrochemical cells in different states of charge are important for practical and usage. Measurement of these parameters in an electrochemical cell is inseparably bound to the electrochemical resistance, temperature and also geometric states of different parts of the cell. In This project we focus on power and resistance of one kind of batteries called thermally activated batteries. These batteries are active after receiving heat and they are inactive at room temperature. Two of the most important models of these batteries that are discussed in this project are LiSi/ LiCl- KCl / FeS2 battery ( with liquid - molten salt electrolyte ) and...
Hot corrosion behavior and near-surface microstructure of a “low-temperature high-activity Cr-aluminide” coating on inconel 738LC exposed to Na2SO4, Na2SO4 + V2O5 and Na2SO4 + V2O5 + NaCl at 900 °C
, Article Corrosion Science ; Volume 128 , 2017 , Pages 42-53 ; 0010938X (ISSN) ; Ghasemi, B ; Sadrnezhaad, S. K ; Habibollahzadeh, A ; Jafarzadeh, K ; Sharif University of Technology
Abstract
Hot corrosion is a serious problem in gas turbines due to poor quality fuels which contain Na, V, S and Cl. To resolve the problem, Cr-aluminide was coated on IN-738LC superalloy with a two steps pack cementation process. Oxidation behavior and near-surface microstructure of the coating showed consecutive increase in destruction by exposition to Na2SO4, 75Na2SO4 + 25 V2O5 and 70Na2SO4 + 25 V2O5 + 5NaCl (wt.%). Kinetic studies indicated parabolic corrosion rate in salt-less samples due to diffusion. Similar expression for salt-covered samples was assessed for oxide dissolution. Plate-like, broken-plate-like and cauliflower-like morphologies attributed to the corrosion products were observed...
Part load behavior of molten salt cavity receiver solar tower plants under storage mode operational mode
, Article ASME 2016 10th International Conference on Energy Sustainability, ES 2016, collocated with the ASME 2016 Power Conference and the ASME 2016 14th International Conference on Fuel Cell Science, Engineering and Technology, 26 June 2016 through 30 June 2016 ; Volume 1 , 2016 ; 9780791850220 (ISBN) ; Shafiei Ghazani, A ; Taylor, R. A ; Saberi, P ; Sharif University of Technology
American Society of Mechanical Engineers
2016
Abstract
The performance of the tower based concentrated solar thermal (CST-tower) plant is very sensitive to the operation strategy of the plant and the incident heat flux on the receiver. To date, most studies have been examined only the design mode characteristics of the cavity receivers, but this paper significantly expands the literature by considering non-design operating conditions of this important sub-component of the CST-tower plants. A feasible non-design operating conditions of the cavity receivers that was considered in this study is the storage mode of operation. Two practical dynamic control strategies were examined then to find the most efficient approach: fixed solar field mass...
Annual comparative performance and cost analysis of high temperature, sensible thermal energy storage systems integrated with a concentrated solar power plant
, Article Solar Energy ; Volume 153 , 2017 , Pages 153-172 ; 0038092X (ISSN) ; Taylor, R. A ; Nithyanandam, K ; Shafiei Ghazani, A ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
The present study conducts a comprehensive comparative techno-economic analysis of some near-term sensible thermal energy storage (TES) alternatives to the ‘standard’ two-tank molten salt system for concentrated solar power (CSP) plants. As such, we conducted detailed, relative annual transient simulations for single-medium thermocline (SMT), dual-media thermocline (DMT), and shell-and-tube (ST) systems. To be consistent with recent literature, the DMT and ST systems use concrete with a porosity of 0.2 (e.g. where concrete occupies 80% of the system) as their low cost filler material. The systems were integrated into a validated 19.9 MWe Gemasolar CSP model, which has a solar multiple of...
Molten salt synthesis of a SiC coating on graphite flakes for application in refractory castables
, Article Ceramics International ; 2016 ; 02728842 (ISSN) ; Bavand Vandchali, M ; Golestani Fard, F ; Nemati, A ; Sharif University of Technology
Elsevier Ltd
Abstract
A silicon carbide coating was formed on the surface of graphite flakes by reaction of molten Si with carbon at 1100-1300. °C in a 95%KCl-5%NaF molten salt under Ar atmosphere. The effect of temperature and Si/graphite ratio in the initial mixture on the quality and the amount of SiC were investigated by XRD and SEM/EDS analyses. Also, the water wettability, oxidation resistance and zeta potential of un-coated and coated graphite were examined by TGA analysis and sedimentation test. The results show the amount of coating to increase in the coated flakes with increasing temperature and Si/graphite ratio. The SiC coating improves water wettability of graphite and acts as a protective layer to...
Electrodeposition of Al, Mn, and Al-Mn alloy on aluminum electrodes from molten salt (AlCl3-NaCl-KCl)
, Article Journal of Applied Electrochemistry ; Volume 39, Issue 8 , 2009 , Pages 1297-1303 ; 0021891X (ISSN) ; Maleki, A ; Danaee, I ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
2009
Abstract
Electrochemical deposition of aluminum and manganese from basic and acidic molten AlCl3-NaCl-KCl mixture on an aluminum electrode at 180 °C was studied by the methods of voltammetry, and potential and current transient. The deposition of aluminum was found to proceed via a nucleation/growth mechanism in basic melt, while the deposition of manganese was found to be diffusion controlled in basic melt. The diffusion coefficient of Mn2+ ions in basic melt, as derived by voltammetry was in agreement with the deductions of transient methods. Analysis of the chronoamperograms indicates that the deposition of manganese on Al was controlled by 3D diffusion controlled nucleation and growth. The...
Electrocrystallization of Pb and Pb assisted Al on aluminum electrode from molten salt (AlCl3-NaCl-KCl)
, Article Journal of Alloys and Compounds ; Volume 478, Issue 1-2 , 2009 , Pages 83-88 ; 09258388 (ISSN) ; Danaee, I ; Maleki, A ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
2009
Abstract
Electrochemical deposition of aluminum and lead from basic molten AlCl3-NaCl-KCl mixture on an aluminum electrode at 180 °C was studied by the methods of voltammetry, potential and current transient and constant current deposition. The deposition of aluminum was found to proceed via a nucleation/growth mechanism, while the deposition of lead was found to be diffusion controlled. The diffusion coefficient calculated for Pb2+ ions in basic melt by voltammetry was in agreement with the deductions of transient method. The analysis of the chronoamperograms indicates that the deposition process of lead on Al substrates was controlled by 3D diffusion control, nucleation and growth. The processes...
Electrodeposition of aluminum from molten AlCl3-NaCl-KCl mixture
, Article Journal of Applied Electrochemistry ; Volume 36, Issue 10 , 2006 , Pages 1169-1173 ; 0021891X (ISSN) ; Mahjani, M.G ; Gobal, F ; Danaee, I ; Sharif University of Technology
2006
Abstract
Electrochemical deposition of aluminum from basic and acidic molten NaCl-KCl-AlCl3 mixture on a graphite electrode at 140 °C was studied by voltammetry, chronopotentiometry and constant current deposition. The deposition of aluminum was found to proceed via a nucleation/growth mechanism in basic melt, while it was found to be diffusion controlled in acidic melt. The diffusion coefficient calculated for Al2Cl- 7 ions in acidic melt by voltammetry was in agreement with the deductions of voltammetry. The morphology of the aluminum deposits was examined using a metallographic microscope and by SEM. It was shown that, depending on the current density (c.d.) and AlCl3 concentration (acidic or...