Fuel Cell Generator Research Articles

Sizes of Anode and Cathode Affect Electricity Generation in Rice Paddy-Field Microbial Fuel Cells

Rice paddy-field microbial fuel cells (RPF-MFCs) are devices that exploit rhizosphere bacteria to generate electricity from soil organic matter, including those excreted from roots. Previous studies have examined factors affecting electric outputs from RPF-MFCs and demonstrated that RPFMFC was able to generate electricity up to 80 mW·m-2 (based on the projected area of anode). The present study operated RPF-MFCs with different sizes of anodes and cathodes and examined how electrode sizes affected electricity generation. We show that anodes are the limiting factor for electricity generation immediately after commencing the operation, while cathodes become the limiting factor after anode performances are sufficiently increased. RPF-MFC achieved the maximum power density of 140 mW·m-2 (based on the projected area of anode), when the cathode is sufficiently larger than the anode. Results suggest that the cathode needs to be improved for eliciting the maximum capacity of rhizosphere bacteria for electricity generation in RPF-MFC.

The Electricity Generation in Microbial Fuel Cells Using Reaeration Mechanism for Cathodic Oxygen Reduction

Electricity generation in microbial fuel cell (MFC) using reaeration mechanism to facilitate cathodic oxygen reduction is sustainable and economical. This study examined the effects of operational parameters of electrical load (Rext), organic load and cathode area (Sa) on MFC performance under reaeration rate (K2) of 0.5-1.5 d-1in cathode chamber. Two MFCs, consisting of MFC-A (with Rext10 Ω) and MFC-B (Rext1000 Ω), were operated in parallel and continuously fed with influent chemical oxygen demand (CODin) 324–561 mg/L to anode chamber; and in each MFC the Sa covering 184, 553, 992 and 1290 cm2 was tested. Results indicated that in MFC-A the current production increased with aqueous COD in anode chamber, in which the relationship between current and aqueous COD can be modeled with Monod kinetics. The estimated kinetic constants of maximum current Imax is 3 mA, and half-saturation constant of current Ks is 310 mg/L. The lowest dissolved oxygen (DO) of 1.9 mg/L occurred at highest CODin of 561 mg/L. In MFC-B, constant current of 0.4 mA and DO at 3.2-3.7 mg/L were maintained for all CODin. The Sa had insignificant influence on electricity generation in both MFCs. This study demonstrated the importance of electrical load, organic load, and their interactions among them in designing reaeration-assisted MFC for organic waste treatment.

연료전지 발전시스템을 이용한 축소형 철도차량의 운전곡선 추종에 따른 추진제어장치 특성 고찰

The study in railway system to apply a fuel cell system with high efficiency and mobility than other renewable energy is being actively conducted. It is needed a analysis on load characteristics and control method of rolling stock in order to apply to rolling stock. This paper presents study on control small-scale prototype power converter electric railway vehicle using fuel cell generation system. Experiment is conducted through real fuel cell generation system and reference speed applying the driving curve of the actual electric railway vehicle was applied. Also, output voltage of boost converter is controlled considering characteristic of fuel cell. And it was confirmed characteristic according to powering and regeneration of inverter.

A STATCOM Controller for Grid Interfaced Fuel Cell Generation System

This paper presents the concepts of grid interconnection of non-conventional energy sources such as solar, wind plants, fuel generation systems that will give signifying moment in near future. Generally, these energy generating stations are interconnected at PCC for continent consumer applications and due to this the system has high economical, more complex and less reliability in efficiency point of view. The Generated power is transmitted through transmission lines from source to load. It will have some power quality problems like current unbalances and harmonics because of usage in non-linear load due to which the system will lose the reliability. This paper mainly concentrates on the reduction of ripples in line current. For this, we introduced a concept called shunt active filter. This improves the power quality from source to load by using P-Q control through shunt active filter from the output energy of PEM fuel cell in MATLAB Simulink environment.

Single-Stage and Boost-Voltage Grid-Connected Inverter for Fuel-Cell Generation System

According to the requirement of fuel cell generation system, this paper presents a new single-stage and boost-voltage grid-connected inverter, as well as the signal modulation diagram in a line cycle. In the proposed inverter, one of the bridge legs is shared with a boost converter. The boost inductor current is designed in discontinuous conduction mode, which can effectively decrease low-frequency current ripple (LFCR) in the output current of the fuel cell. The switching modes of the proposed inverter are analyzed in positive and negative half line cycles, respectively. The LFCR in the output current of the fuel cell is analyzed, from which the design principle of the boost voltage inductor is obtained. The per-unit current values of the shared switches and the loss of the whole system are derived and compared with those of the conventional inverter. Experimental verifications are presented to verify the theoretical analysis.

대용량 연료전지발전시스템의 계통외란방지알고리즘에 관한 연구

Recently, fuel cell generation system with high energy efficiency and low CO2 emission is energetically interconnected with distribution power system. Especially, MCFC(molten carbonate fuel cell) operating at high temperature conditions is commercialized and installed as a form of large scale power generation system. However, it is reported that power system disturbances such as harmonic distortion, surge phenomenon, unbalance current, EMI(Electromagnetic Interference), EMC (Electromagnetic Compatibility) and so on, have caused several problems including malfunction of protection device and damage of control devices in the large scale FCGS(Fuel Cell Generation System). Under these circumstances, this paper proposes countermeasure algorithms to prevent power system disturbances based on the modelling of PSCAD/EMTDC and P-SIM software. From the simulation results, it is confirmed that proposed algorithms are useful method for the stable operation of a large scale FCGS.

Impact of Korean Ginseng (Panax Ginseng) on Power Generation of Microbial Fuel Cells

Impact of Korean Ginseng (Panax Ginseng) on Power Generation of Microbial Fuel Cells

Chemically Functionalized Conjugated Oligoelectrolyte Nanoparticles for Enhancement of Current Generation in Microbial Fuel Cells.

Water-soluble conjugated oligoelectrolyte nanoparticles (COE NPs), consisting of a cage-like polyhedral oligomeric silsesquioxanes (POSS) core equipped at each end with pendant groups (oligo(p-phenylenevinylene) electrolyte, OPVE), have been designed and demonstrated as an efficient strategy in increasing the current generation in Escherichia coli microbial fuel cells (MFCs). The as-prepared COE NPs take advantage of the structure of POSS and the optical properties of the pendant groups, OPVE. Confocal laser scanning microscopy showed strong photoluminescence of the stained cells, indicating spontaneous accumulation of COE NPs within cell membranes. Moreover, the electrochemical performance of the COE NPs is superior to that of an established membrane intercommunicating COE, DSSN+ in increasing current generation, suggesting that these COE NPs thus hold great potential to boost the performance of MFCs.

Current sharing in parallel fuel cell generation system based on model predictive control

Parallel connection is usually adapted in fuel cell system for the high power applications. Fuel cell subsystem has different dynamic characteristics. The connection will show imbalance in load sharing and current distribution. Thus a robust parallel operation and current sharing algorithm is required. In this paper the block diagram of parallel fuel cell generation system is presented, and a master-slave model predictive control (MPC) method is proposed for the current-sharing control of the systems. Neural network optimization is used to reduce the computational time of single step optimization in model predictive control. The proposed MPC-based current sharing strategy is verified to be feasible and effective.

A DSP-based interleaved boost DC–DC converter for fuel cell applications

Multiphase interleaved boost DC–DC converters are typically used as a fuel cell power conditioner due to their low input ripple current. This paper presents analysis and design of a 2-phase interleaved boost DC–DC converter controlled by a single chip DSP to enhance reliability and flexibility. The PI regulator for the output voltage control was tuned by the extended symmetrical optimum method to optimally operate in the fuel cell ohmic region with a guaranteed phase margin of 45° for the entire fuel cell voltage range. The set point weighting technique was used for soft starting, which was effective. The effects of switching and sampling time delays were analysed and compensated. Experimental results of the 1-kW, 120-V prototype converter connected with a PEM fuel cell stack closely agreed with simulation results in MATLAB/Simulink. The DSP-based fuel cell converter has the potential for further development as a compact fuel cell generator or fuel cell electric vehicle with embedded online diagnosis and fault-tolerant operation.

Employing a Flexible and Low-Cost Polypyrrole Nanotube Membrane as an Anode to Enhance Current Generation in Microbial Fuel Cells.

The flexible and low-cost polypyrrole nanotube membrane is demonstrated as a promising anode in microbial fuel cells, which significantly enhances the extracellular electron transfer between Shewanella oneidensis MR-1 and the electrode, owing to the large active surface area and high electrical conductivity.

연료전지 시스템을 이용한 전기철도 급전계통 전압강하 보상

In this paper, fuel cell power generation system that is being studied in recent railway field was applied to compensate for the voltage drop due to the load as driving electric vehicle. PSIM simulation program is to be used to implement the modeling of the electric railway for AC AT feeder system. For it, It was applied to the product-type single-phase PLL algorithm, step-down converter is controlled as power so as to have the fuelcell generation system.BR Based on it’s result, a reactive power due to the catenary impedance in accordance with the current flowing is compensated as linked with fuelcell generation system which supplied the current to the power supply grid. and then its performance was confirmed that voltage compensation effect obtained at SubStation (SS), SubSectioning Post (SSP), Sectioning Post (SP)

Concept of URT Traction DC Microgrid and its Application Feasibility Study

Firstly, based on the structure of urban rail transit traction power supply system and the characteristics of typical dc microgrid, a concept of urban rail transit traction power dc microgrid was proposed in the paper, and the feasibility of photovoltaic generation system, fuel cells generation system and energy storage system gridded to urban rail transit traction power supply system were studied; and then the functions and advantages of the proposed traction dc microgrid were surveyed from energy-saving and power supply reliability; finally, based on analyzing the electrical characteristics of urban rail transit traction catenary, some key issues of urban rail transit traction dc microgrid technology to be solved were discussed.

Evaluation of Low‐Cost Separators for Increased Power Generation in Single Chamber Microbial Fuel Cells with Membrane Electrode Assembly

AbstractWe compared novel size‐selective separators, namely the textile fabrics of polyphenylene sulfide (PPS) and sulfonated polyphenylene sulfide (S‐PPS), and the nonwoven fabrics of polypropylene80 (PP 80) and PP 100, with commonly used ion exchange separators (Nafion 117 and cation exchange membane‐7000; CMI‐7000) in terms of power generation, oxygen diffusion, and biofilm formation in a single chamber microbial fuel cell. Size‐selective separators exhibited more power generation than ion selective separators. MFC operation with size‐selective separators generated power output ranging 0.407 to 0.591 V (1000 Ω), whereas with Nafion it was 0.272 V. In polarization analysis, S‐PPS resulted in the highest power density of 190 mW/m2, whereas it was 24 mW/m2 with Nafion‐117. Size selective separators showed similar or higher proton conductivity than Nafion 117. Oxygen mass transfer coefficients of size‐selective separators (KO = 3.7 ∼ 7.5 × 10−5) were lower or similar to Nafion (KO = 7.5 × 10−5). Fourier‐transform infrared spectroscopy and scanning electron microscopy analysis revealed that all separators (PP80, S‐PPS, and Nafion) contained proteins or carbon chain compounds after 300‐day operation, and however, Nafion 117 seems to be more susceptible to biofouling than the other separators.

Conductive Polymer/Graphene Supported Platinum Nanoparticles as Anode Catalysts for the Extended Power Generation of Microbial Fuel Cells

Platinum (Pt) nanoparticles anchored over reduced graphene oxide (rGO) and rGO/conductive polyaniline (PANI) composites were synthesized and exploited as anode catalysts in microbial fuel cells (MFC). PANI bridges rGO and Pt nanoparticles through the electrostatic interaction/π–π stacking force/hydrogen bonding and Pt–N bond, respectively, and increased the intrinsic stability of rGO/PANI/Pt composite. The electrocatalytic performances of rGO/PANI/Pt exhibited the better oxidation current and lower internal resistance over the prepared rGO/PANI and rGO/Pt composites as evidenced from the cyclic voltammetric and electrochemical impedance techniques, respectively. By the combined efforts of active support, high electrical conductivity, and number of catalytic active sites, the prepared rGO/PANI/Pt nanocomposite exhibited a maximum MFC power density of 2059 mW/m2 with the concrete life durability. Thus, the proposed approach has paved new dimensions in not only the preparation of rGO-supported conductive pol...

Effect of surface transport properties on the performance of carbon plastic electrodes for flow battery applications

Due to their high electrical conductivity and corrosion resistance, carbon nanotube (MWNT)-high density polyethylene (HDPE) composites are potential candidates to replace traditional activated carbon electrodes for the next generation of fuel-cells, super capacitors and flow batteries. Electrochemical impedance spectroscopy (EIS) is employed to separate the surface conduction from bulk conduction in 15% HDPE-MWNT and 19% carbon black (CB)-HDPE composites for zinc-bromine flow battery electrodes. While exhibiting superior bulk conductivity, the interfacial conductivity of MWNT-filled composites is lower than that of CB-filled composites. High resolution conductive atomic force microscopy (C-AFM) imaging and current-voltage (I-V) spectroscopy were employed to investigate the sub-surface electronic transport of the composite. Unlike the CB-composite, the fraction of conducting MWNTs near the surface is very low compared to their volume fraction. In addition, the non-linear I-V curves reveal the presence of a tunneling junction between the tip and the polymer-coated MWNTs. The tunneling resistance is as high as 1GΩ, which strongly affects the electronic/electrochemical transfer at the interface of the electrolyte and the surface of the composite, which is evident in the voltammetric and EIS observations.

Design Approach for the Development of the Flow Field of Bipolar Plates for a PEMFC Stack Prototype

This work is part of a project whose final aim is the realization of an auxiliary power fuel cell generator. It was necessary to design and develop bipolar plates that would be suitable for this application. Bipolar plates have a relevant influence on the final performances of the entire device. A gas leakage or a bad management of the water produced during the reaction could be determinant during operations and would cause the failure of the stack. The development of the bipolar plates was performed in different steps. First, the necessity to make an esteem of the dynamics that happen inside the feeding channels led to perform analytical calculations. The values found were cross-checked performing a computational fluid dynamics (CFD) simulation; finally, it was defined the best pattern for the feeding channels, so that to enhance mass transport and achieve the best velocity profile. The bipolar plates designed were machined and assembled in a laboratory scale two cells prototype stack. Influences of the temperature and of the humidity were evaluated performing experiments at 60 deg and 70 deg and between 60% and 100% of humidity of the reactant gasses. The best operating point achieved in one of these conditions was improved by modifying the flow rates of the reactant, in order to obtain the highest output power, and it evaluated the reliability of the plates in experiments performed for longer times, at fixed voltages.

Development of Multi-Cell Active Switched- Capacitor and Switched-Inductor Z-Source Inverter Topologies

This paper proposes new active switched-capacitor and switched-inductor Z-source inverter (ASC/SL-ZSI) topologies, which can provide a higher boost ability with a small shoot-through time. The proposed ASC/SL-ZSIs inherit all of the advantages of the classical ZSI, and have a stronger voltage boost inversion ability when compared with the classical ZSI. Thus, the output ac voltage quality is significantly improved. In addition, more cells can be cascaded in the impedance network in order to obtain a very high boost ability. The proposed topologies can be applied to photovoltaic or fuel-cell generation systems with low-voltage renewal sources due to their wide range of obtainable voltages. Both simulations and the experimental results are carried out in order to verify performance of the proposed topologies.

External CO2 and water supplies for enhancing electrical power generation of air-cathode microbial fuel cells.

Alkalization on the cathode electrode limits the electrical power generation of air-cathode microbial fuel cells (MFCs), and thus external proton supply to the cathode electrode is essential to enhance the electrical power generation. In this study, the effects of external CO2 and water supplies to the cathode electrode on the electrical power generation were investigated, and then the relative contributions of CO2 and water supplies to the total proton consumption were experimentally evaluated. The CO2 supply decreased the cathode pH and consequently increased the power generation. Carbonate dissolution was the main proton source under ambient air conditions, which provides about 67% of total protons consumed for the cathode reaction. It is also critical to adequately control the water content on the cathode electrode of air-cathode MFCs because the carbonate dissolution was highly dependent on water content. On the basis of these experimental results, the power density was increased by 400% (143.0 ± 3.5 mW/m(2) to 575.0 ± 36.0 mW/m(2)) by supplying a humid gas containing 50% CO2 to the cathode chamber. This study demonstrates that the simultaneous CO2 and water supplies to the cathode electrode were effective to increase the electrical power generation of air-cathode MFCs for the first time.

Contribution of Sulfate-Reducing Bacteria to the Electricity Generation in Microbial Fuel Cells

Double-chambered microbial fuel cells (MFCs) were used to investigate the effect of sulfate and sulfate-reducing bacteria (SRB) on electricity generation by molybdate inhibition coupled with PCR-DGGE technique. Results showed that low influent sulfate (< 1470 mg/L) improved power density and voltage, while higher sulfate blocked the MFC efficiency. Molybdate inhibited the activity of SRB and consequently decreased MFC voltage and power density which confirmed some SRB were involved in the electricity generation. Microbial community analysis indicated thatDesulfovibrio desulfuricanscontributed to the electricity production and stability of MFC.