Encontrados 33 documentos, a visualizar página 1 de 4
Water management in a passive direct methanol fuel cell
Oliveira, V. B.; Falcão, D. S.; Rangel, C. M.; Pinto, A. M. F. R.Passive direct methanol fuel cells (DMFCs) are under development for use in portable applications because of their enhanced energy density in comparison with other fuel cell types. The most significant obstacles for DMFC development are methanol and water crossover because methanol diffuses through the membrane generating heat but no power. The presence of a large amount of water floods the cathode and reduces ...
Simulation of a stand-alone residential PEMFC power system with sodium borohydr...
Pinto, P. J. R.; Sousa, T.; Fernandes, Vitor R.; Pinto, A. M. F. R.; Rangel, C. M.Catalytic hydrolysis of sodium borohydride (NaBH4) has been investigated as a method to generate hydrogen for fuel cell applications. The high purity of the generated hydrogen makes this process a potential source of hydrogen for polymer electrolyte membrane fuel cells (PEMFCs). In this paper, a PEMFC power system employing a NaBH4 hydrogen generator is designed to supply continuous power to residential power ...
Experimental and modeling studies of a micro direct methanol fuel cell
Falcão, D. S.; Rangel, C. M.; Pinto, A. M. F. R.The Direct Methanol Fuel Cell (DMFC) has attracted much attention due to its potential applications as a power source for transportation and portable electronic devices. Based on the advantages of the scaling laws, miniaturization promises higher efficiency and performance of power generating devices and the MicroDMFC is therefore an emergent technology. In this work, a set of experiences with a MicroDMFC of 2....
Micro direct methanol fuel cell: experimental and modelling studies
Falcão, D. S.; Rangel, C. M.; Pinto, A. M. F. R.The Direct Methanol Fuel Cell (DMFC) has attracted much attention due to its potential applications as a power source for transportation and portable electronic devices. Based on the advantages of the scaling laws, miniaturization promises higher efficiency and performance of power generating devices and the MicroDMFC is therefore an emergent technology. In this work, a set of experiences with a MicroDMFC of 2....
Hydrogen generation by borohydrides: critical issues for portable applications
Fernandes, Vitor R.; Ferreira, M. J. F.; Pinto, A. M. F. R.; Rangel, C. M.High volumetric and gravimetric efficiency are key to potential hydrogen energy carriers. Sodium borohydride emerges as such potentiality and a storage capacity well within DOE targets for 2015. Limitations exist due to the fact that hydrolysis is restricted by available water and due to the lack of low cost re-usable catalysts. An extensive amount of work has been done in our laboratories on Ni and Ru based ca...
Current density distribution mapping in polymer electrolyte membrane fuel cell
Sousa, T.; Falcão, D. S.; Pinto, A. M. F. R.; Rangel, C. M.A non-uniform utilization of the active area due to inhomogeneous current density distribution is one of the main factors for poor fuel cell performance. Furthermore, it leads to hot points which can be responsible for thermal stress in the membrane electrode assemble (MEA). Therefore, it became extremely important to have a consistent technic to visualize in real time the current density and temperature distri...
Analysis of a stand-alone residential PEMFC Power system with sodium borohydrid...
Pinto, P. J. R.; Fernandes, Vitor R.; Pinto, A. M. F. R.; Rangel, C. M.Catalytic hydrolysis of sodium borohydride (NaBH4) has been investigated as a method to generate hydrogen for fuel cell applications. The high purity of the generated hydrogen makes this process an ideal source of hydrogen for polymer electrolyte membrane fuel cells (PEMFCs). In this paper, the possibility of using a NaBH4-based hydrogen generator with a PEMFC for stand-alone residential use is examined. A comp...
Impact of the reactor bottom shape on the solid sodium borohydride hydrolysis f...
Ferreira, M. F. R.; Fernandes, Vitor R.; Rangel, C. M.; Pinto, A. M. F. R.Sodium borohydride (NaBH4) is a chemical hydride that produces hydrogen (H2) ‘on-demand’ through the reaction with water, and exhibits high gravimetric hydrogen storage capacity (10.8 wt.%). NaBH4 has been appointed as an efficient energy/hydrogen carrier for use with fuel cells [1-6]. Unfortunately, problems also exist with NaBH4 hydrolysis: H2 production rates are not sufficiently fast, reaction completion is...
Innovative reactor prototype for Hydrogen production in a stationary applicatio...
Barbosa, Rui; Ferreira, V.; Silva, D.; Condes, J.; Ramos, S.; Amaral, V.; Pinto, A. M. F. R.; Figueiredo, A.; Rangel, C. M.Hydrogen storage has proved to be the greatest obstacle preventing hydrogen from replacing fossil fuels. Hence, a safe, efficient and economical method of storing hydrogen must be available to turn viable a hydrogen economy based on renewable resources [1]. Hydrogen can be stored in chemical hydrides such as sodium borohydride (NaBH4), with large theoretical H2 content of 10,9 wt%. With the aid of catalysts, an...
The effect of NaOH on the kinetics of Hydrogen production from sodium borohydri...
Fernandes, Vitor R.; Ferreira, M. J.; Pinto, A. M. F. R.; Rangel, C. M.Previous work by the authors has demonstrated a high rate and high yield hydrolysis of sodium borohydride in the presence of a Ni-Ru catalyst synthesized by wet chemistry. The catalyst has been fully characterized and utilized more than 300 times, exhibiting high stability and durability. In this work, the effect of temperature on the reaction rate was studied and the activation energy of the process estimated ...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||