Water Electrolysis (water + electrolysis)

Distribution by Scientific Domains

Selected Abstracts

Geothermal-based hydrogen production using thermochemical and hybrid cycles: A review and analysis

M. Tolga Balta
Abstract Geothermal-based hydrogen production, which basically uses geothermal energy for hydrogen production, appears to be an environmentally conscious and sustainable option for the countries with abundant geothermal energy resources. In this study, four potential methods are identified and proposed for geothermal-based hydrogen production, namely: (i) direct production of hydrogen from the geothermal steam, (ii) through conventional water electrolysis using the electricity generated through geothermal power plant, (iii) by using both geothermal heat and electricity for high temperature steam electrolysis and/or hybrid processes, and (iv) by using the heat available from geothermal resource in thermochemical processes. Nowadays, most researches are focused on high-temperature electrolysis and thermochemical processes. Here we essentially discuss some potential low-temperature thermochemical and hybrid cycles for geothermal-based hydrogen production, due to their wider practicality, and examine them as a sustainable option for hydrogen production using geothermal heat. We also assess their thermodynamic performance through energy and exergy efficiencies. The results show that these cycles have good potential and attractive overall system efficiencies over 50% based on a complete reaction approach. The copper-chlorine cycle is identified as a highly promising cycle for geothermal-hydrogen production. Copyright 2009 John Wiley & Sons, Ltd. [source]

Study of a fuel cell network with water electrolysis for improving partial load efficiency of a residential cogeneration system

S. Obara
Abstract A fuel cell energy network which connects hydrogen and oxygen gas pipes, electric power lines and exhaust heat output lines of the fuel cell cogeneration for individual houses, respectively, is analysed. As an analysis case, the energy demand patterns of individual houses in Tokyo are used, and the analysis method for minimization of the operational cost using a genetic algorithm is described. The fuel cell network system of an analysis example assumed connecting the fuel cell cogeneration of five houses. If energy is supplied to the five houses using the fuel cell energy network proposed in this paper, 9% of city gas consumption will be reduced by the maximum from the results of analysis. Two per cent included with 9% is an effect of introducing water electrolysis operation of the fuel cells, corresponding to partial load operation of fuel cell cogeneration. Copyright 2005 John Wiley & Sons, Ltd. [source]

Polarization curves for an alkaline water electrolysis at a small pin vertical electrode to produce hydrogen,

AICHE JOURNAL, Issue 9 2010
Ph. Mandin
Abstract During two-phase electrolysis for hydrogen production, according with alkaline,water electrolysis process, there are bubbles which are created at electrodes which imply a great hydrodynamic acceleration in the normal earth gravity field and then a quite important electrical properties and electrochemical processes disturbance, for both transport and reaction. This disturbance can lead to the modification of the local current density and to anode effects for example. In this work, a model experimental set-up is studied. The vertical pine electrode of small electro active surface area is surrounded with a large surface counter electrode. The hydrogen production is performed at the working electrode and effort is focused here upon the global electrochemical cell electrical performances. The polarization curves intensity vs. applied voltage are experimentally measured and presented for different factors such as: the electro active species concentration, nature and counter electrode diameter factors. 2010 American Institute of Chemical Engineers AIChE J, 2010 [source]

Effect of gas evolution on mixing and conversion in a flow-through electrochemical reactor

AICHE JOURNAL, Issue 9 2009
Matthew A. Petersen
Abstract Flow-through electrolytic reactors (FTER) emplaced below the subsurface may be used to control the migration of groundwater contamination away from source zones. During prior studies with FTERs, water electrolysis and associated gas generation have occurred concurrently with contaminant degradation. Gas evolution-induced mixing within the electrode assembly has the potential to impact system performance. A mathematical model of the system was developed to capture the impact of mixing on transport processes in the system. Corresponding transient and steady-state tracer experiments using ferricyanide as a model contaminant were conducted to quantify mixing-dependent parameters and verify modeling results. Over a range of relevant groundwater flowrates, Peclet numbers were between 0.1 and 10, indicating that mixing was a important process under low-flow conditions. Comparison of experiments and model calculations demonstrated that incorporating gas evolution into the model was necessary for accurate performance prediction. 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

Indirect Raman identification of the proton insertion in the high-temperature [Ba/Sr][Zr/Ti]O3 -modified perovskite protonic conductors,

Aneta Slodczyk
Abstract OH, and H3O+ species in hydrates and simple oxides are rather well characterised from their IR, Raman and inelastic neutron points of view. For the H+ (H2O) species in solid state the variability is well established and assignment remains discussed. The question of the vibrational signature of isolated proton (e.g. the ionic proton, a proton sharing its interaction with more than two acceptors) and its dynamic nature (proton gas, polaron,,) is open. H+ -containing modified perovskites A(Ba,Sr,,) B(Zr,Ce,Ti,,) O3 are potential ceramic membranes for fuel cell and medium temperature water electrolysis (300,800 C). Comparison studies of the protonated and non-protonated lanthanide/rare earth-modified perovskites of type Ba(Sr)Zr(Ti)O3 as well as Al-modified BaTiO3 show that a broad component centred at 2500 cm,1 is observed after ,proton insertion'. Its intensity is correlated to the protonic species content as well as to the conductivity of the materials. The mixed nature of this feature is discussed: fluorescence related to the dangling bonds, A, B, C bands or new phenomena related to the ionic protons and associated electronic defect. Copyright 2008 John Wiley & Sons, Ltd. [source]