فهرست مطالب

Hydrogen, Fuel Cell and Energy Storage - Volume:3 Issue: 4, Autumn 2016

Journal of Hydrogen, Fuel Cell and Energy Storage
Volume:3 Issue: 4, Autumn 2016

  • تاریخ انتشار: 1395/10/18
  • تعداد عناوین: 6
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  • Mona Moayeri, Ali Kaflou *, Davood Sadeghi Pages 255-266
    Recently, the use of renewable energies has increased to environmental pollution, limitation of fossil energy resources and energy security One of the means that enable us to use such energies is fuel cells (FC). However, there are many problems in the commercialization of FC from an economically and operation perspective. One of the most important problems is heat management. New heat pipes are being developed for this purpose. A heat pipe is made from a “porous coat” on a base metal. In this study, a Cu-Ni porous layer with a thickness of ~300µm was considered as the coating on a Cu-Ni base metal with two kinds of powder (mixed and ball milled). The morphology and physical properties of the coatings, such as porosity, permeability and effective thermal conductivity, were investigated. The best permeability was obtained for the base metals coated with powder which was ball milled for 6 hours. Thermal conductivity of samples increased (by 9.5%) when using ball milled powder. Porosity of coated samples decreased with ball milled powder in comparison to mixed powder.
    Keywords: Copper-Nickel powder, Sintered porous wicks, Porosity, Permeability, heat Pipe, Fuel cell, Thermal Conductivit
  • Hassan Ali Ozgoli * Pages 267-279
    Exergy analysis of an integrated molten carbonate fuel cell-turbo expander-steam turbine hybrid cycle has been presented in this study. The proposed cycle has been used as a sustainable energy approach to provide a micro hybrid power plant with high exergy efficiency. To generate electricity by the mentioned system, an externally reformed molten carbonate fuel cell located upstream of the combined cycle has been used. Furthermore, the turbo expander and steam turbine systems have been considered as topping and bottoming cycles for the purpose of cogeneration, respectively. Results show that the proposed system is capable of reaching a net delivered power of 1125 kW, while the total exergy efficiency (including both electricity and heat) of this system is more than 68%. Moreover, the delivered power and exergy efficiency from the proposed cycle is stable against ambient temperature variations. In addition, the effect of a current density increase on cell voltage and total exergy destruction has been considered.
    Keywords: Molten Carbonate Fuel Cell, Turbo Expander, Steam Turbine, Exergy Efficiency, Hybrid Cycle
  • Atiyeh Ebrahimi, Ghasem Najafpour *, Daryoush Kebria Pages 281-290
    Microbial desalination cells (MDCs) have great potential as a cost-effective and green technology for simultaneous water desalination, organic matter removal and energy production. The aim of this study was to compare the performance of a MDC under batch and continuous feeding conditions. Hence, power and current output, coulombic efficiency, electron harvest rate, desalination rate and COD removal were calculated during the operation. According to the obtained results, the MDC performance exhibited some changes when the reactor switched from batch to continuous mode. The continuously operated MDC indicated a maximum power density of 15.9 W.m-3 and an average salt removal rate of 80%. In comparison, the batch MDC demonstrated the maximum power density and average salt removal rate of 13.9 W.m-3 and 68.1%, respectively. In addition, 83.7% of COD was removed in the continuously fed MDC at a hydraulic retention time of two days, which was 13.8% more than amount of COD removed in MDC under a two days batch process. The obtained results revealed that enrichment of anolyte under controlled continuous feeding conditions would relatively improve the MDC performance.
    Keywords: Batch process, Continuous process, Microbial desalination cell, Wastewater treatment, Power density
  • Mohammad Ali Ghafouri Roozbahani, Mahmoud Ziarati *, Nahid Khandan Pages 291-299
    Ternary Cu/ZnO/metal oxide catalysts are prepared through the co-precipitation method under strict control of parameters like pH, calcination conditions, and precipitation temperature in a systematic manner. The metal oxides applied in this study consist of Al2O3, ZrO2, La2O3 and Ce2O3. The distinction of this work in comparison with similar research is a comprehensive investigatation of the catalytic properties of metal oxides (including conversion, selectivity and stability) which have the potential for use in the methanol steam reforming process. The catalysts are characterized through XRD, SEM and BET. The prepared catalysts are applied in methanol steam reforming in a fixed bed reactor. A TGA analysis performed for all four catalysts determined that the Ce2O3 and ZrO2 metal oxide catalysts showed the best results in terms of stability with a coke formation of 0.7wt% and 0.8wt%, respectively; and maximum surface area is related to Cu/ZnO/Ce2O3, which can result in excellent stability and Cu dispersion. Overall, the obtained results indicate that the ZrO2 metal oxide catalyst is the best candidate to be applied in methanol steam reforming due to its higher activity, selectivity and yield. The hydrogen selectivity and yield of Cu/ZnO/ZrO2 after 6 hours of experiment were 80.02% and 46.4%, respectively.
    Keywords: Methanol steam reforming, Hydrogen, Cu-based catalyst, Co- precipitation, Metal oxide
  • Morteza Rajabinasab, Mehran Ameri *, Masoud Iranmanesh, Saber Sadeghi Pages 301-313
    In this study, the effect of recycling fuel cell products on the performance of a solid oxide fuel cell and gas turbine (SOFC-GT) hybrid system was investigated. Three types of products recycling are considered: cathode products recycling (CPR), anode products recycling (APR), and both cathode and anode products recycling (BACPR). In the present work, operating temperature and limiting current density was calculated from governing equations by the trial and error method. Furthermore, the effect of pressure ratio and air utilization factor on the performance of the SOFC-GT hybrid system is considered. Results show that CPR has more effect on the performance of hybrid systems than APR. The total electrical efficiency of the hybrid system increases as the cathode recycle ratio (CRR) increases and decreases as the anode recycle ratio (ARR) decreases. In addition, results show that the hybrid system with BACPR can achieve a higher overall electrical efficiency of approximately 75%.
    Keywords: Hybrid system, Solid oxide fuel cell, Gas turbine, Cathode product recycling, Anode product recycling
  • Elaheh Amir, Mehran Rezaei *, Fereshteh Meshkani Pages 315-322
    In this study, nickel catalysts supported on mesoporous nanocrystalline gamma alumina promoted by various strontium contents were prepared by the impregnation method and employed in dry reforming of methane (DRM). The prepared catalysts were characterized using N2 adsorption (BET), temperature-programmed reduction and oxidation (TPR,) and oxidation (TPDTPO), X-ray diffraction (XRD), and scanning electron microscopy (SEM) techniques. TPR analysis revealed that the increases in Sr content enhanced the reducibility of the catalysts. The obtained results indicated that increasing Sr content increased both the methane and carbon dioxide conversions. In addition, the CO2 conversion was higher than the CH4 conversion due to the occurrence of the reverse water gas shift reaction. Among the studied catalysts, Ni/10% Sr-Al2O3 exhibited the highest catalytic activity and the lowest carbon formation. This catalyst showed high stability without any decrease in methane conversion up to 12 h of reaction. The results of this study could be employed in developing an industrial catalyst for the dry reforming reaction.
    Keywords: Nickel catalyst, Strontium, Dry reforming, Nanocrystalline