Energy Conversion using electrolytic concentration gradients
- PDF / 313,405 Bytes
- 12 Pages / 432 x 648 pts Page_size
- 106 Downloads / 224 Views
Energy Conversion using electrolytic concentration gradients
Subramaniam Chittur K1,2 , Aishwarya Chandran3 , Ashwini Khandelwal3 , Sivakumar A4 1 Materials
Physics Department, VIT University, Vellore, TN, India. Executive Fellow, College of Engineering and Science, Victoria University, Footscray, 3011,Victoria, Australia. 3 School of Mechanical and Building Sciences, VIT University, Vellore, TN, India. 4 Environmental & Analytical Chemistry Division School of Advanced Sciences, VIT University, Vellore, TN, India. 2 Endeavour
ABSTRACT
Salinity gradient is an enormous source of clean energy. A process for potential generation from an ionic concentration gradient produced in single and multicell assembly is presented. The ionic gradient is created using a fuel cell type cell with a micro-porous ion exchange membrane, both anionic (AEM) and cationic (CEM). Various salinity gradients, Salt : Fresh, from 100 : 0 to 16000 : 0 was established using NaCl solution, in the electrode chambers. A potential of 20 mV/cm to 25 mV/cm can be realized at ambient temperatures and pressures for a bipolar AEM/CEM cell. The performance was optimized for various static and dynamic flow rates of the saline and fresh water. The cell performance can further be optimized for Membrane Electrode System (MES) morphology. A multicell unit was assembled and the results presented for various conditions like concentration gradients, flow rates and pressure. The thermodynamic and electrical efficiency needs to be evaluated for various gradients and flow rates. The relation with number of valance electrons/ ion and the potential generated changes for various dynamic condition of salinity. The higher the salinity gradient the larger is the potential generated. This is limited by the membrane characteristics. There exists a monotonic relation between the number of valence electron/ion/unit time and the potential generated up to about 16000 concentration. The membrane characteristics have been studied for optimal ion crossover for various gradients and flow. The graph between ln (gradient) versus Voltage provides insights into this process. This presents a very cost effective and clean process of energy conversion.
51
INTRODUCTION
Concentration gradients are noticed everywhere. Production of electric power from such gradients was introduced by Pattle R E in 1954.[1] An exhaust of any form, natural or otherwise sees a concentration gradient of molecules across a system or area.[2] Similarly, one of the biggest sources of one type of such gradient are estuaries. Natural and an everlasting process, estuaries cause large volumes of water of varying saline content to mix. Salinity gradient power (SGP) is the energy that can be generated from reversible mixing of two kinds of water with different salt contents.[3, 4, 5] A man made source of such a gradient are exit pipes from industries and sewage treatment plants into a water body. Diffusion and mixing will inevitably take place, it is a matter of deriving its potential before it takes place. The osmotic p
Data Loading...
