HYBRID SULFUR ELECTROLYZER DEVELOPMENT, NHI WORK PACKAGE N-SR07TC0301, FY07 FIRST QUARTER REPORT.

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Book Synopsis HYBRID SULFUR ELECTROLYZER DEVELOPMENT, NHI WORK PACKAGE N-SR07TC0301, FY07 FIRST QUARTER REPORT. by : W. Summers

Download or read book HYBRID SULFUR ELECTROLYZER DEVELOPMENT, NHI WORK PACKAGE N-SR07TC0301, FY07 FIRST QUARTER REPORT. written by W. Summers and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The proof of concept of SO2 electrolysis for the hybrid sulfur (HyS) process is the second priority research target of the DOE Nuclear Hydrogen Initiative's thermochemical program for FY07. The proof of concept of the liquid-phase option must be demonstrated at the single cell level for an extended run times (>100 hours). The rate of development of HyS will depend on the identification of a promising membrane or an alternative means for controlling sulfur formation. Once successful long-duration operation has been demonstrated, SRNL will develop a multi-cell stack that can be connected to the H2SO4 decomposer being developed by SNL for the S-I ILS for a Hybrid Sulfur Integrated Laboratory-Scale Experiment during FY 2008. During the first quarter of FY07, SRNL continued the component development and membrane development activities with the goal of identifying and characterizing improved electrodes, electrocatalysts, membranes and MEA configurations which could then be tested at larger scale in the SDE test facility. A modified glass cell was fabricated to allow measurements of sulfur dioxide (SO2) transport across membrane samples at elevated temperatures (up to 70 C). This testing also includes evaluating SO2 transport in different sulfuric acid concentrations (30-70 wt%). A new potentiostat/frequency analyzer was installed for determining ionic conductivity of membranes. This instrument enhances our capabilities to characterize membrane, electrocatalyst and MEA properties and performance. Continuing work from FY06, evaluations were preformed on various commercial and experimental membranes and electrocatalyst materials for the SDE. Several different types of commercially-available membranes were analyzed for sulfur dioxide transport as a function of acid strength including perfluorinated sulfonic acid (PFSA), sulfonated polyetherketone-ketone, and poly-benzimidazole (PBI) membranes. Experimental membranes from the sulfonated diels-alder polyphenylenes (SDAPP) and modified Nafion{reg_sign} 117 were evaluated for SO{sub 2} transport as well. These membranes exhibited reduced transport coefficient for SO{sub 2} transport without the loss in ionic conductivity.

HYBRID SULFUR ELECROLYZER DEVELOPMENT, NHI WORK PACKAGE N-SR07TC0301, FY08 FIRST QUARTER REPORT.

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Book Synopsis HYBRID SULFUR ELECROLYZER DEVELOPMENT, NHI WORK PACKAGE N-SR07TC0301, FY08 FIRST QUARTER REPORT. by :

Download or read book HYBRID SULFUR ELECROLYZER DEVELOPMENT, NHI WORK PACKAGE N-SR07TC0301, FY08 FIRST QUARTER REPORT. written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogen has been identified as a leading candidate to replace petroleum as part of the transition to a sustainable energy system, and major efforts are being conducted worldwide to develop the technologies and supporting activities required for this transition. In the United States, the federal research efforts are led by the U.S. Department of Energy (DOE). The U.S. DOE Hydrogen Program is an integrated inter-office program being conducted by the Office of Energy Efficiency and Renewable Energy, Office of Nuclear Energy (DOE-NE), Office of Fossil Energy and Office of Science. The primary objective of the DOE-NE Nuclear Hydrogen Initiative (NHI) is to develop the nuclear hydrogen production technologies necessary to produce hydrogen at a cost competitive with other alternative transportation fuels. The focus of the NHI is on thermochemical cycles and high temperature electrolysis. The Savannah River National Laboratory (SRNL) has been tasked with the primary responsibility to perform research and development in order to characterize, evaluate and develop the Hybrid Sulfur (HyS) thermochemical process. The HyS Process uses a sulfur dioxide depolarized electrolyzer (SDE) to split water and produce hydrogen. During FY05 and FY06, SRNL designed and conducted proof-of-concept testing for a SDE using a low temperature, PEM fuel cell-type design concept. The advantages of this design concept include high electrochemical efficiency and small footprint, characteristics that are crucial for successful implementation on a commercial scale. During FY07, SRNL extended the range of testing of the SDE to higher temperature and pressure, conducted a 100-hour longevity test, and designed and built a larger, multi-cell stack electrolyzer. The proof of concept of SO2 electrolysis for the HyS Process is a priority research target for the FY 2008 NHI Program. Technical options must be better defined and the challenges better understood. The current status of electrolyzer performance must be established by operation at elevated temperature (>90C) and pressure (>10 atmospheres) and during a long duration run (>100 hours). SRNL is pursuing the liquid-phase sulfur dioxide decoupled electrolyzer (SDE) option, which is the main focus of the NHI work. The rate of development of HyS will depend on the identification of a promising membrane or an alternative means for controlling sulfur formation at the cathode of the cell. SRNL will work with Sandia National Laboratory (SNL), universities, and industry to address this issue. Electrolyzers of larger size will be required as the process development proceeds, and SRNL will test a multi-cell stack that was built in FY 2007. Work will be initiated for a Hybrid Sulfur Integrated Laboratory-Scale (ILS) Experiment that will combine a SRNL electrolyzer with the sulfuric acid decomposer developed by SNL for the S-I ILS. A review will be held at mid-year, and if progress warrants, work will progress to the ILS level including ILS system design, electrolyzer fabrication and infrastructure development. Benchmarks to be considered include electrochemical efficiency, membrane durability, and minimization of SO2 crossover.

HYBRID SULFUR ELECTROLYZER DEVELOPMENT FY09 SECOND QUARTER REPORT.

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Book Synopsis HYBRID SULFUR ELECTROLYZER DEVELOPMENT FY09 SECOND QUARTER REPORT. by :

Download or read book HYBRID SULFUR ELECTROLYZER DEVELOPMENT FY09 SECOND QUARTER REPORT. written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of the DOE-NE Nuclear Hydrogen Initiative (NHI) is to develop the nuclear hydrogen production technologies necessary to produce hydrogen at a cost competitive with other alternative transportation fuels. The focus of the NHI is on thermochemical cycles and high temperature electrolysis that can be powered by heat from high temperature gas reactors. The Savannah River National Laboratory (SRNL) has been tasked with the primary responsibility to perform research and development in order to characterize, evaluate and develop the Hybrid Sulfur (HyS) thermochemical process. This report documents work during the first quarter of Fiscal Year 2009, for the period between January 1, 2009 and March 31, 2009. The HyS Process is a two-step hybrid thermochemical cycle that is part of the 'Sulfur Family' of cycles. As a sulfur cycle, it uses high temperature thermal decomposition of sulfuric acid to produce oxygen and to regenerate the sulfur dioxide reactant. The second step of the process uses a sulfur dioxide depolarized electrolyzer (SDE) to split water and produce hydrogen by electrochemically reacting sulfur dioxide with H2O. The SDE produces sulfuric acid, which is then sent to the acid decomposer to complete the cycle. The DOE NHI program is developing the acid decomposer at Sandia National Laboratory for application to both the HyS Process and the Sulfur Iodine Cycle. The SDE is being developed at SRNL. During FY05 and FY06, SRNL designed and conducted proof-of-concept testing for a SDE using a low temperature, PEM fuel cell-type design concept. The advantages of this design concept include high electrochemical efficiency, small footprint and potential for low capital cost, characteristics that are crucial for successful implementation on a commercial scale. During FY07, SRNL extended the range of testing of the SDE to higher temperature and pressure, conducted a 100-hour longevity test with a 60-cm2 single cell electrolyzer, and designed and built a larger, multi-cell stack electrolyzer. During FY08, SRNL continued SDE development, including development and successful testing of a three-cell electrolyzer stack with a rated capacity of 100 liters per hour. The HyS program for FY09 program will address improving SDE performance by focusing on preventing or minimizing sulfur deposition inside the cell caused by SO2 crossover, reduction of cell voltage for improved efficiency, an extension of cell operating lifetime. During FY09 a baseline technology development program is being conducted to address each of these issues. Button-cell (2-cm2) and single cell (60-cm2) SDEs will be fabricated and tested. A pressurized button-cell test facility will be designed and constructed to facilitate addition testing. The single cell test facility will be upgraded for unattended operation, and later for operation at higher temperature and pressure. Work will continue on development of the Gas Diffusion Electrode (GDE), or Gap Cell, as an alternative electrolyzer design approach that is being developed under subcontract with industry partner Giner Electrochemical Systems. If successful, it could provide an alternative means of preventing sulfur crossover through the proton exchange membrane, as well as the possibility for higher current density operation based on more rapid mass transfer in a gas-phase anode. Promising cell components will be assembled into membrane electrode assemblies (MEAs) and tested in the single cell test facility. Upon modification for unattended operation, test will be conducted for 200 hours or more. Both the button-cell and modified single cell facility will be utilized to demonstrate electrolyzer operation without sulfur build-up limitations, which is a Level 1 Milestone.