Nanopore Confinement of Electrocatalysts Optimizing Triple Transport for an Ultrahigh‐Power‐Density Zinc–Air Fuel Cell with Robust Stability

2020 ◽  
Vol 32 (47) ◽  
pp. 2003251
Author(s):  
Tianpei Zhou ◽  
Huan Shan ◽  
Hao Yu ◽  
Cheng'an Zhong ◽  
Jiankai Ge ◽  
...  
Author(s):  
Adriano Sciacovelli ◽  
Vittorio Verda ◽  
Cristina Amelio ◽  
Carlo Repetto ◽  
Gustavo Diaz

In this paper, the prototype of a circular Molten Carbonate Fuel Cell (MCFC) built in the laboratories of FN SpA Nuove Tecnologie e Servizi Avanzati is analyzed using a tridimensional computational fluid dynamic (CFD) model. The prototype is the result of FN and Politecnico di Torino activities developed for the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) within the framework of Ministry of Economic Development, MSE-ENEA. This model considers heat, mass and current transfer as well as chemical and electrochemical reactions. The results show that some inhomogeneous distributions in the reactants, causing non-optimal use of the reactant surfaces. An effective way to improve the distribution in current density consists in tracing tree shaped channels on the surface onto the distribution porous medium. In this paper Y shaped channels are adopted to improve the distribution of gas within the fuel cell and consequently to enhance the performance of the original design of the fuel cell. In addition, the configuration of the outlet of the anodic compartment is also investigated in order to further increase the performance of the fuel cell. The geometrical parameter identifying the topology of distribution channels are chosen accordingly to the constructal theory. The results show that significant improvements can be achieved. Power density is increased of about 6% when the tree-shaped channel is adopted. If a double anodic inlet is also considered the enhancement in the power density is of about 11% with respect to the initial configuration.


Author(s):  
Eric Liese

This paper examines the arrangement of a solid oxide fuel cell (SOFC) within a coal gasification cycle, this combination generally being called an integrated gasification fuel cell cycle. This work relies on a previous study performed by the National Energy Technology Laboratory (NETL) that details thermodynamic simulations of integrated gasification combined cycle (IGCC) systems and considers various gasifier types and includes cases for 90% CO2 capture (2007, “Cost and Performance Baseline for Fossil Energy Plants, Vol. 1: Bituminous Coal and Natural Gas to Electricity,” National Energy Technology Laboratory Report No. DOE/NETL-2007/1281). All systems in this study assume a Conoco Philips gasifier and cold-gas clean up conditions for the coal gasification system (Cases 3 and 4 in the NETL IGCC report). Four system arrangements, cases, are examined. Cases 1 and 2 remove the CO2 after the SOFC anode. Case 3 assumes steam addition, a water-gas-shift (WGS) catalyst, and a Selexol process to remove the CO2 in the gas cleanup section, sending a hydrogen-rich gas to the fuel cell anode. Case 4 assumes Selexol in the cold-gas cleanup section as in Case 3; however, there is no steam addition, and the WGS takes places in the SOFC and after the anode. Results demonstrate significant efficiency advantages compared with IGCC with CO2 capture. The hydrogen-rich case (Case 3) has better net electric efficiency compared with typical postanode CO2 capture cases (Cases 1 and 2), with a simpler arrangement but at a lower SOFC power density, or a lower efficiency at the same power density. Case 4 gives an efficiency similar to Case 3 but also at a lower SOFC power density. Carbon deposition concerns are also discussed.


2022 ◽  
pp. 1-33
Author(s):  
Xiuqin Zhang ◽  
Wentao Cheng ◽  
Qiubao Lin ◽  
Longquan Wu ◽  
Junyi Wang ◽  
...  

Abstract Proton exchange membrane fuel cells (PEMFCs) based on syngas are a promising technology for electric vehicle applications. To increase the fuel conversion efficiency, the low-temperature waste heat from the PEMFC is absorbed by a refrigerator. The absorption refrigerator provides cool air for the interior space of the vehicle. Between finishing the steam reforming reaction and flowing into the fuel cell, the gases release heat continuously. A Brayton engine is introduced to absorb heat and provide a useful power output. A novel thermodynamic model of the integrated system of the PEMFC, refrigerator, and Brayton engine is established. Expressions for the power output and efficiency of the integrated system are derived. The effects of some key parameters are discussed in detail to attain optimum performance of the integrated system. The simulation results show that when the syngas consumption rate is 4.0 × 10−5 mol s−1cm−2, the integrated system operates in an optimum state, and the product of the efficiency and power density reaches a maximum. In this case, the efficiency and power density of the integrated system are 0.28 and 0.96 J s−1 cm−2, respectively, which are 46% higher than those of a PEMFC.


Author(s):  
Utku Gulan ◽  
Hasmet Turkoglu ◽  
Irfan Ar

In this study, the fluid flow and cell performance in cathode side of a proton exchange membrane (PEM) fuel cell were numerically analyzed. The problem domain consists of cathode gas channel, cathode gas diffusion layer, and cathode catalyst layer. The equations governing the motion of air, concentration of oxygen, and electrochemical reactions were numerically solved. A computer program was developed based on control volume method and SIMPLE algorithm. The mathematical model and program developed were tested by comparing the results of numerical simulations with the results from literature. Simulations were performed for different values of inlet Reynolds number and inlet oxygen mole fraction at different operation temperatures. Using the results of these simulations, the effects of these parameters on the flow, oxygen concentration distribution, current density and power density were analyzed. The simulations showed that the oxygen concentration in the catalyst layer increases with increasing Reynolds number and hence the current density and power density of the PEM fuel cell also increases. Analysis of the data obtained from simulations also shows that current density and power density of the PEM fuel cell increases with increasing operation temperature. It is also observed that increasing the inlet oxygen mole fraction increases the current density and power density.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Jian-sheng Huang ◽  
Ping Yang ◽  
Chong-ming Li ◽  
Yong Guo ◽  
Bo Lai ◽  
...  

In order to study the effect of nitrite and nitrate on the performance of microbial fuel cell, a system combining an anaerobic fluidized bed (AFB) and a microbial fuel cell (MFC) was employed for high-strength nitrogen-containing synthetic wastewater treatment. Before this study, the AFB-MFC had been used to treat high-strength organic wastewater for about one year in a continuous flow mode. The results showed that when the concentrations of nitrite nitrogen and nitrate nitrogen were increased from 1700 mg/L to 4045 mg/L and 545 mg/L to 1427 mg/L, respectively, the nitrite nitrogen and nitrate nitrogen removal efficiencies were both above 99%; the COD removal efficiency went up from 60.00% to 88.95%; the voltage was about 375 ± 15 mV while the power density was at 70 ± 5 mW/m2. However, when the concentrations of nitrite nitrogen and nitrate nitrogen were above 4045 mg/L and 1427 mg/L, respectively, the removal of nitrite nitrogen, nitrate nitrogen, COD, voltage, and power density were decreased to be 86%, 88%, 77%, 180 mV, and 17 mW/m2 when nitrite nitrogen and nitrate nitrogen were increased to 4265 mg/L and 1661 mg/L. In addition, the composition of biogas generated in the anode chamber was analyzed by a gas chromatograph. Nitrogen gas, methane, and carbon dioxide were obtained. The results indicated that denitrification happened in anode chamber.


2020 ◽  
Vol 44 (7) ◽  
pp. 5968-5976 ◽  
Author(s):  
Meshack I. Simeon ◽  
Felix U. Asoiro ◽  
Mohamad Aliyu ◽  
Olayinka A. Raji ◽  
Ruth Freitag

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