424844 Improved Modeling and Neutron Imaging Experiments for the Analysis of a Blue Energy Cycle

Tuesday, November 10, 2015: 4:51 PM
Canyon A (Hilton Salt Lake City Center)
Jorge F. Gabitto1, Ketki Sharma2, Yong-Ha Kim2, Sotira Yiacoumi3 and Costas Tsouris4, (1)Chem. Eng., PVAMU, Prairie View, TX, (2)Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, (3)School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, (4)Energy and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, TN

The energy obtained by salinity-gradients, also known as blue energy, is a promising renewable energy source. Mixing a high-concentration saline solution, such as seawater, with fresh water, such as river water, to produce a brackish solution dissipates more than 2.2 MJ of free energy per m3 of fresh water. The goal of this project is to optimize the recovery efficiency of free energy change by using a newly developed model that is capable to deal with pores of any size, and performing neutron imaging experiments to visualize the distribution of ions in the electrodes at all steps of a blue-energy cycle.  The new model increases the simulation efficiency by being able to handle new types of electrodes developed recently. The morphology, pore size, and carbon electrode composition are chosen to maximize the charging-discharging steps of the reversible cycle, while minimizing charge leak and irreversible steps in the process. The cycle design is done by careful consideration of the processes inside the electrode and the corresponding effects on the reversible energy cycle. A proposed energy cycle comprises a charging step, a discharging step and two switching steps that replace a saltwater solution inside the pores by a freshwater solution and vice versa. In-situ neutron imaging experiments revealed interesting behavior during these steps that can be used to further optimize the cycle. Simulations show good agreement between experimental data and computed results.

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