M. Minutillo

Assessment of Fuel Cell Performance Under Different Air Stoichiometries and Fuel Composition

The behavior of fuel cells (FCs) at steady state and during transients is an important factor both for control tuning and for performance assessment. In the technical literature, few papers deal systematically with FC characterization. In this paper, the performance characterization of a proton exchange membrane (PEM) FC is carried out using an experimental analysis. The experimental activity has been conducted in a test station, properly designed and able to test PEM FC stacks in the range of 500-2000 W. The laboratory test facility is equipped with a National Instruments CompactDAQ real-time data acquisition and control system running a LabVIEW software. The bench commands two mass flow controllers, regulating both fuel flow and air flow which are commanded via two Recommended Standard 232 ports. The temperature of the FC is regulated via a fan operated by a brushless motor drive. An electronic load is connected to the FC terminals. The main operating parameters, such as the air stoichiometric ratio and fuel composition, have been varied and measured, and their influence on the PEM FC behavior has been investigated under both steady-state and transient conditions.

Performance of a Polymer Electrolyte Membrane Fuel Cell System Fueled With Hydrogen Generated by a Fuel Processor

Fuel cells, which have seen remarkable progress in the last decade, are being developed for transportation, as well as for both stationary and portable power generation. For residential applications, the fuel cells with the largest market segment are the proton exchange membrane fuel cells, which are suitable for small utilities since they offer many advantages: high power density, small footprint, low operating temperature, fast start-up and shutdown, low emissions, and quiet operation. On the other hand, polymer electrolyte membrane (PEM) fuel cells require high purity hydrogen as fuel. Currently, the infrastructure for the distribution of hydrogen is almost nonexistent. In order to use PEM fuel cell technology on a large scale, it is necessary to feed them with conventional fuel such as natural gas, liquefied petroleum gas, gasoline or methanol to generate hydrogen in situ. This study aims to predict the performance of a PEM fuel cell integrated with a hydrogen generator based on steam reforming process. This integrated power unit will be able to provide clean, continuous power for on-site residential or light commercial applications. A precommercial natural gas fuel processor has been chosen as hydrogen generator. This fuel processor contains all the elements-desulphurizer, steam reformer, CO shift converter, CO preferential oxidation (PROX) reactor, steam generator, burner, and heat exchanger-in one package. The reforming system has been modeled with the ASPEN PLUS code. The model has a modular structure in order to allow performance analysis, component by component. Experimental investigations have been conducted to evaluate the performance of the fuel cell fed with the reformate gas, as produced by the reformer. The performance of the integrated system reformer/fuel cell has been evaluated both using the numerical results of the reformer modeling and the experimental data of the PEM fuel cell.

Fluid Dynamic Investigation of Channel Design in High Temperature PEM Fuel Cells

In this paper we analyze the three-dimensional flow field in anode and cathode gas channels of polymer electrolyte membrane (PEM) fuel cells operating at high temperature (T > 100°C). Different gas flow channel designs (pin-type, parallel channels, comb-tipe and multiple serpentine), as well as different channel sections (squared, trapezoidal and rounded with different curvature radii) are evaluated in function of some relevant parameters. The analysis is performed accounting for overall pressure losses, gas distribution over the electrode area and residence time with focus on channel hydraulic diameter, active surface ratio, gas path. Differences with low temperature (LT) PEM fuel cell design are also adressed. The investigation is conducted by means of 3D-CFD softwares and the results of our simulations are compared to experimental data in literature.

Microbial Fuel Cells in Solid Waste Valorization: Trends and Applications

In recent years, biomass valorization (and, in general, waste treatment) and FC technology met in the so-called bioelectrochemical systems (BESs). BESs take advantage of biological capacities (microbes, enzymes, plants) for the catalysis of electrochemical reactions. They mainly include micro-electrolysis Cell (MECs) and microbial fuel cells (MFCs). While MECs can produce valuable compounds (like H2, CH4, etc.), providing a suitable potential at the electrodes, MFCs do not need any energetic input to convert chemical energy (stored in organic compounds) into electric power. In this “biologically-based-fuel–cells,” the fuel is made by different sources of organic compounds. Landfill leachate, municipal and agro-industrial wastewaters, sediments, solid organic wastes can be source of electric power and commodity chemicals. The use of MFC technology to waste treatment and valorization is, maybe, the most promising application of this newborn technology. Even though many researchers proved the reliable utilization of liquid waste as fuel in scaled MFCs, few attempts to apply MFCs to solid waste valorization have been done. In this paper, recent studies about the application of MFCs to solid substrates treatment and valorization and the contribution that BESs and MFC in particular could give to the development of a more sustainable waste management.

Life Cycle Cost Analysis of Hydrogen Energy Technologies

Abstract Today, in the global economy, characterized by a growing awareness of environmental issue, the life cycle costing analysis (LCCA) is receiving increasing attention in various sectors. This is a critical task for modern businesses. In fact, the procurement decisions for many products are made on their life cycle costs. In this context, the hydrogen technologies play an important role. Actually, even though they have been known for a long time, aspects of system analysis, energy economics, and ecology received much less attention. For those reasons, the aim of this work is twofold. First, this study aims to contribute to the development of a comprehensive study on LCCA of hydrogen energy technologies. Second, it aims to propose a simple framework, called “ABC” analysis based on life cycle cost approach and multicriteria decision analysis useful to carry out an integrated analysis to compare different results and to balance economic data.

Development of a system-level model for fuel cell power units operated with syngas

This paper deals with a system-level modelling for the performance prediction of power units based on fuel cells that are designed to work witha syngas or with a fuel that can contain CO, such as HT-PEMFCs, MCFCs and SOFCs. The model solves mass and energy balances and allows to estimate the polarization curves by applying mathematical equations that take into account the different type of fuel cell. The empirical coefficients of the model equations have been tuned by using available experimental data.

Measuring the PEM fuel cell performance in a versatile test station

In this paper the performance characterization of a PEM fuel cell has been carried out using an experimental analysis. The experimental activity has been conducted in a test station, properly designed and able to test PEM fuel cell stacks in the range 500−2000 W. The laboratory test facility is equipped by a National Instruments Compact DAQ real-time data acquisition and control system running LabView software. The bench commands two mass-flow controllers, regulating both fuel flow and air flow which are commanded via two RS232 ports. The temperature of the FC is regulated via a fan operated by a brushless motor drive. An electronic load is connected to the FCM. The main operating parameters, such as air stoichiometric ratio and fuel composition, have been varied and measured and their influence on the PEM fuel cell behavior has been investigated under both steady-state and transient conditions.

Modelling and Testing a PEM Fuel Cell Fuelled by a Steam Reforming System

In this paper the performance of a natural gas power system has been discussed. The power generation unit is composed by a fuel cell and a fuel processor integrated in a compact system. The hydrogen generator uses the steam reforming technology. A CO shift converter and a preferential oxidation reactor are used to minimize the CO concentration in the reformate gas. The hydrogen dilution in the reformate gas calls for a modification of the fuel cell feeding system. The dead-end mode is not practicable for the fuel cell operation, but it is necessary to open the anode flow channels. In order to increase the efficiency of the integrated system, the anode off gas mass flow is burned to supply heat for the reforming reaction. The fuel cell performance has been evaluated using the test bed of the University of Cassino. The experimental activity has been focused to evaluate the performance in different operating conditions. A semi-empirical model of the fuel cell has been employed to forecast the fuel cell behaviour with pure hydrogen and reformate gas feeding. The semi-empirical coefficients of the model have been fitted by using the experimental data. The target of the fuel cell modelling has been to develop a tool capable of predicting the performance in different operating conditions. The same tool can be used to identify the areas for design improvements.Copyright

Thermochemical Modelling and Analysis of a Compact Reforming System for PEM FC Application

The main objective of this study is to foresee the performance of a PEM fuel cell generator operating as an emergency backup power system. The fuel cell generator is fuelled by hydrogen supplied by a compact reforming system. The reforming system must be able to use a carbon-based fuel, such as natural gas, standard gasoline or diesel to generate hydrogen for clean, on-site electrical power production. Hydrogen generation is provided by a non-catalytic reformer using high-voltage discharges to assist the exothermic partial oxidation process. Thermo-chemical modelling has been implemented considering both reforming system and hydrogen purification unit. The purification and separation unit must be able to produce high purity hydrogen because concentration of CO has to be strongly reduced before entering the fuel cell stack. A comparative performance analysis of different fuels for hydrogen generation has been provided. Thermochemical modelling has been conducted by means of Aspen Plus code.Copyright