Design and development of micro direct methanol fuel cell (μDMFC) for portable application

A passive, air-breathing single cell and a multi-cell stack micro direct methanol fuel cell with 1.0 cm2 active area were designed, fabricated and tested. The fuel cell was completely passive without any ancillary device such as pump. Oxygen was taken from the surrounding air, and the methanol solution was stored in a built-in reservoir. The performance of the single cell was tested with different methanol concentrations ranging from 1.0 M to 5.0 M, and the optimum performance was achieved by using methanol at a concentration of 4.0 M. A stack with 6 cells was fabricated and tested with the optimum methanol concentration of 4.0 M, and power levels produced by different catalyst loadings on the anode were compared. The combination of a catalyst loading of 3.0 mg cm-2 Pt/Ru on the anode and 2.0 mg cm-2 Pt on the cathode yielded the highest power of 12.05 mW at 1.08 V and 11.2 mA

Design of an optimal micro direct methanol fuel cell for portable applications

The main constraint for the commercialization of micro Direct Methanol Fuel cell (μDMFC) for small power generation is the performance of the fuel cell. In this study, a high-power μDMFC with a power output of 14.10 mW on an active area of 4 cm2 and catalyst loading of 0.5 mg cm-2 cathode was successfully developed. The optimal parameters for methanol concentration and catalyst loading were determined. Besides that, testing of performance, long term and open circuit voltage (OCV) was also performed

Characteristic Drying Curve of Oil Palm Fibers

The drying of crushed oil palm fronds was studied in a fluidized bed dryer assisted with mechanical agitation at different inlet air temperature, superficial air velocity, bed loading and agitation speed. The drying kinetics of the fibers under various drying conditions could be described by a single characteristic drying curve. A combined exponential and power law model is proposed to represent the characteristic drying curve which described both the increasing rate and the falling rate periods. The proposed model is also tested for drying kinetics of oil palm empty fruit bunch from previous researcher. It was found that the characteristic curve for both oil palm fronds and empty fruit bunch fibers has similar shape and that the proposed model is acceptable for describing the complete drying characteristics of the fibers

Nanocomposite Electrolyte for PEMFC Application

Fuel demand is predicted to increase by 6.3% by each year, in particular the motor vehicle sector where is expected to increase by 41% per year. Gas generated from burning fossil fuels produce emission that cause global warming effect as perceived from the parameters such as (i) increase in global temperature, (ii) global climate change phenomena and (iii) the melting of the ice caps. One effort to overcome the effects of global warming is by replacing fossil fuels with hydrogen fuel. Hydrogen fuel and fuel cell technology had been proven able to minimise the production of toxic flue gases produced by combustion of fossil fuels. Hydrogen fuel is one of the first order candidate to replace fossil fuels because the combustion of hydrogen produce only electricity and water without the emission on of CO2, NOx, SOx and volatile organic compounds. In addition, hydrogen as a raw material can be renewed and could be harvested from multiple processing methods. Some countries have tried to produce renewable fuels with a large capacity as would be done by China by 2020 where it is expected to produce 20% of the renewable energy while New Zealand at 70%, Brazil has been producing bio-fuels on large scale and U.S. bio-fuel have been supplied from corn. U.S. and Japan have reserved the hydrogen as a substitute for fossil fuel. It is estimated that hydrogen fuel to be economical by 2050. Fuel cell technology will be one of the appropriate technologies to convert hydrogen into electric energy when hydrogen is continuously supplied. Fuel cell would be able to replace fossil-fuelled engine with higher efficiency and expected to produce minimum or no pollutants and have been developed in order to reduce the problems of green house gas effect produced through the combustion of fossil fuel

ELECTROCHEMICAL PROPERTIES IMPROVEMENT OF PROTON EXCHANGE MEMBRANE FUEL CELL (PEMFC) USING NANOCOMPOSITE ELECTROLYTE MEMBRANE.

Nafion-Silica oxide (SiO2)-Phosphotungstic acid (PWA) composite membrane have been synthesized using solution phase sol-gel method. The effect of the weight ratio of Nafion:SiO2:PWA to the electrochemical properties of composite membrane when applies as electrolyte in the PEMFC was investigated using Fuel Cell Test System (FCTS) at temperature of range of 80 – 90 oC and 40% relative humidity (RH). The weight ratio of the composite membrane samples varied in the range of 100:2.88:1.15, 100:4.33:1.73 and 100:5.76:2.30 and designated as NS10W, NS15W and NS20W, respectively. The aim of the experiment was to insert the inorganic hygroscopic and high conductivity filler like PWA and SiO2 in the Nafion matrix to order to improve the water retention, proton conductivity (σ), hydrogen crossover (β), and thermal stability in addition to increase PEMFC performance at elevated temperature and low RH condition. The result showed when appropriately embeded in the Nafion cluster, the hydrated PWA and SiO2 were endowed in the composite membrane with their high proton conductivity, while retaining the desirable mechanical properties of the polymer film. The water uptake rate and the conductivity of the composite membranes was enhanced with the increase in SiO2 and PWA weight content, after which it is reduced when the ratio of Nafion:SiO2:PWA became 100:4.33:1.73. However, the conductivity of all the composite membranes were higher compare to the Nafion membrane at cell operation condition of 80 – 90 oC and 40% RH. While hydrogen crossover through the composite is lower than Nafion 112 membrane. This study indicated that Nafion-SiO2-PWA composite membrane can be a viable substitute for Nafion for PEMFC which showed good conductivity comparable to Nafion 112 at temperature nearing 100 oC, bearing in mind that Nafion-SiO2-PWA composite membranes have better thermal stability

Nafion/silicon oxide/phosphotungstic acid nanocomposite membrane with enhanced proton conductivity.

Nafion-silicon oxide (SiO2)-phosphotungstic acid (PWA) composite membrane has been synthesized to improve Nafion based proton exchange membrane fuel cell (PEMFC) performance. The objective of the study is to fabricate Nafion-SiO2-PWA nanocomposite membrane using sol–gel reaction. The composite is composed of the mixture of Nafion solution, tetra ethoxy orthosilane (TEOS) and PWA solution. The mixed solution was casted at certain temperature until transparent membrane is obtained. Peaks of SiO2 and PWA in the infrared spectra revealed that both inorganic and organic components are present in the modified Nafion based nanocomposite membrane. Analysis with fuel cell test station showed that higher current density was produced by nanocomposite membrane (82mAcm−2 at 0.6V for NS15W) than with the Nafion membrane (30mAcm−2 at 0.2 V) at 90 ◦C and 40% relative humidity. The internal resistance was seen to increase with the inorganic content. The internal resistances of the commercial Nafion (N112), NS10W, NS15W and NS20W are 6.33, 4.84, 1.33 and 3.6�cm2, respectively and their Tafel constants are 93.4, 84.4, 11.25 and 26.6 mV, respectively. While the nanocomposite membrane results were shown to be better than the commercial Nafion, the overall performances are comparable to those in the open literature

Thermo-electrical performance of PEM fuel cell using Al2O3 nanofluids

Nanofluid adoption as an alternative coolant for Proton Exchange Membrane (PEM) fuel cell is a new embarkation which hybridizes the nanofluids and PEM fuel cell studies. In this paper, findings on the thermo-electrical performance of a liquid-cooled PEM fuel cell with the adoption of Al2O3 nanofluids were established. Thermo-physical properties of 0.1, 0.3 and 0.5% volume concentration of Al2O3 nanoparticles dispersed in water and water: Ethylene glycol (EG) mixtures of 60:40 were measured and then adopted in PEM fuel cell as cooling medium. The result shows that the cooling rate improved up to 187% with the addition of 0.5% volume concentration of Al2O3 nanofluids to the base fluid of water. This is due to the excellent thermal conductivity property of nanofluids as compared to the base fluid. However, there was a penalty of higher pressure drop and voltage drop experienced. Thermo electrical ratio (TER) and Advantage ratio (AR) were then established to evaluate the feasibility of Al2O3 nanofluid adoption in PEM fuel cells in terms of both electrical and thermo-fluid performance considering all aspects including heat transfer enhancement, fluid flow and PEM fuel cell performance. Upon analysis of these two ratios, 0.1% volume concentration of Al2O3 dispersed in water shows to be the most feasible nanofluid for adoption in a liquid-cooled PEM fuel cell

Microbial fuel cells using mixed cultures of wastewater for electricity generation

Fossil fuels (petroleum, natural gas and coal) are the main resources for generating electricity. However, they have been major contributors to environmental problems. One potential alternative to explore is the use of microbial fuel cells (MFCs), which generate electricity using microorganisms. MFCs uses catalytic reactions activated by microorganisms to convert energy preserved in the chemical bonds between organic molecules into electrical energy. MFC has the ability to generate electricity during the wastewater treatment process while simultaneously treating the pollutants. This study investigated the potential of using different types of mixed cultures (raw sewage, mixed liquor from the aeration tank & return waste activated sludge) from an activated sludge treatment plant in MFCs for electricity generation and pollutant removals (COD & total kjeldahl nitrogen, TKN). The MFC in this study was designed as a dual-chambered system, in which the chambers were separated by a NafionTM membrane using a mixed culture of wastewater as a biocatalyst. The maximum power density generated using activated sludge was 9.053 mW/cm2, with 26.8% COD removal and 40% TKN removal. It is demonstrated that MFC offers great potential to optimize power generation using mixed cultures of wastewater