Farm wood fuel and energy project

This paper describes the findings of the Farm Wood Fuel and Energy Project. It began in 1991 and ended in 1997 and was undertaken to provide a commercial demonstration for the establishment of 50 hectares of short rotation coppice (SRC) on six farms in southern England and the development of associated marketing activities. The Project:

• — taught farmers how best to grow the crop and will enable them to teach others;

• — determined that winter conditions in the UK are unsuitable for most harvesting equipment trialled and that both harvesting and chip storage need to be re-examined;

• — demonstrated that SRC has the potential to be competitive with fossil fuels;

• — gave confidence to Government to include a Band for energy crops under the NFFO electricity generating procedures

     

Optical investigations of fuel deposition burning in ported fuel injection (PFI) spark-ignition (SI) engine

The present paper discusses the results obtained by experimental investigations of the diffusion-controlled flame near the valves due to fuel film deposition in a single cylinder, ported fuel injection (PFI), four-stroke spark-ignition (SI) engine with a four-valve production head. The engine was equipped with a transparent combustion chamber with a wide quartz window in the bottom.     

Regional nuclear fuel cycle centres: IAEA study project

A study project on regional nuclear fuel cycle centres was initiated by the International Atomic Energy Agency in 1975 to examine the economic, safety, safeguards and security aspects of a multinational approach to the planning and establishment of nuclear fuel cycle facilities. The study has concentrated on the ‘back end’ of the fuel cycle, covering transport, storage, processing and recycling activities. The results of this study would help any group of interested member states to develop alternative strategies for their present and projected nuclear fuel cycle needs, as well as evolve institutional, legal and other appropriate arrangements for establishing fuel cycle centres on a multinational cooperative basis.     

质子交换膜燃料电池

因其具有独特的优点，质子交换膜燃料电池（PEMFC）的市场前景很好，国际上已经形成了一股研究开发热潮。电催化剂、质子交换膜、双极板、燃料、水管理、热管理是质子交换膜燃料电池的关键技术。文章介绍了PEMFC的特点及开发应用状况，综述了PEMFC的研究进展。     

Nanocatalyst for direct methanol fuel cell (DMFC)

Nanotechnology has recently been applied to direct methanol fuel cells (DMFC), one of the most suitable and promising options for portable devices. With characteristics such as low working temperature, high energy-conversion efficiency and low emission of pollutants, DMFCs may help solve the future energy crisis. However, a significant limitation to DMFC includes slow reaction kinetics, which reduces performance and power output. Recently, research has focused on increasing the performance and activity of catalysts. Catalysts composed of small, metallic particles, such as platinum and ruthenium, supported on nanocarbons or metal oxides are widely used in DMFC. Thus, this paper presents an overview of the development of nanocatalysts for DMFC. Particularly, this review focuses on nanocatalyst structure, catalyst support, and challenges in the synthesis of nanocatalyst. This paper also presents computational approaches for theoretical modeling of nanomaterials such as carbon nanotubes (CNT) through molecular dynamic techniques.     

Fuel cell mobile lighting: A fuel cell market transformation project

We report the results of a project aimed to introduce proton exchange membrane (PEM) hydrogen fuel cell technology into aviation ground support equipment (GSE) and rental construction equipment. The purpose of the project was to design, build, field-test and then commercialize fuel cell equipment that is superior to its diesel counterpart. The commercializing of this hydrogen-based technology will help to start the process of displacing diesel fuel use in aviation GSE and in mobile construction equipment. We describe a hydrogen fuel cell mobile lighting tower (H₂LT) that combines hydrogen stored as a high pressure gas, PEM fuel cell technology, and advanced lighting into a single unit with uses in aviation and construction. We assembled a project team of 15 institutional partners combining new technology expertise (hydrogen, fuel cells), equipment mass manufacturing capability (mobile light towers, lighting) and influential end-users to field test the H₂LT in real-world use in diverse environments. Seed funding provided by Boeing enabled additional funding from the U.S. Department of Energy (DOE) and a preponderance of in-kind contributions from the industrial partners. Prototype units were constructed and field tested in the entertainment industry, at the San Francisco International Airport, at the NASA Kennedy Space Center, with the California Department of Transportation (Caltrans), and with the Connecticut Department of Transportation. The goals of these approximately year-long field tests were to assess operation of the H₂LT technology in a wide variety of potentially corrosive environments (cold, wet, hot, humid, salty air) performing a wide variety of tasks, to reduce diesel emissions at these locations, and to help promote hydrogen PEM technology in new influential markets. The H₂LT proved to be exceptionally durable in these diverse environments, demonstrating the compatibility of PEM fuel cells and high-pressure hydrogen storage with the construction equipment application. Results from the field tests are discussed, including system performance (efficiency, duration, durability) and the efficacy of refueling the system by different methods (H₂ stations, mobile refueling). The H₂LT system is compared directly to a comparable diesel-fueled light tower with regard to size, performance and emissions savings. Overall, end users were pleased with the performance of the H₂LT, noting the lack of emissions and exceptionally low noise level. Recommendations for improvement were also collected and will be discussed. Two types of lighting used on the H₂LT (plasma, LED) were characterized by U.C. Davis in collaboration with Caltrans. LED lighting was found to be the most energy efficient and robust lighting technology for the highly mobile H₂LT application. The technical “lessons-learned” are reviewed, along with the plans for commercialization of the H₂LT technology by Multiquip Inc. Finally, the benefits to the industrial participants of the project organization are described.     

A fuel cell powered autonomous surface vehicle: The Eco-SWAMP project

Autonomous surface vehicles are becoming consolidated robotic tools for marine, coastal and inland surveys. Autonomous surface vehicles are usually equipped with electronic instruments to perform remotely controlled or autonomous geo-morphological, biological, chemical, physical analyses and data collection. Actually, well-established solutions provide battery power but the research focuses on introducing a fuel cell to decrease the environmental impact meanwhile increasing the cruising range. In this paper, the design of the Eco-SWAMP, a fuel cell powered autonomous surface vehicle, is presented starting from its battery-powered version, the SWAMP prototype. The experimental power consumption profile of the SWAMP during four missions is analysed to define the primary energy sources ratings of the Eco-SWAMP. After a commercial choice of primary sources, power management algorithms are designed and compared in MATLAB/Simulink environment by simulation results. The proposed procedure can be easily applied to any autonomous marine vehicle.     

Autoignition of surrogate biodiesel fuel (B30) at high pressures: Experimental and modeling kinetic study

Ignition delay times of surrogate biodiesel fuels were measured in a high-pressure shock tube over a wide range of experimental conditions (pressures of 20 and 40 bar, equivalence ratios in the range 0.5–1.5, and temperatures ranging from 700 to 1200 K). A detailed chemical kinetic mechanism developed for the oxidation of a biodiesel fuel and a B30 biodiesel surrogate (49% n-decane, 21% 1-methylnaphthalene, and 30% methyloctanoate in mol%) was used to simulate the present experiments. Cross reactions between radicals from the three fuel components and reactions of methylnaphthalene oxidation recently proposed in the literature were introduced into the model in order to improve ignition delay time predictions at low temperatures. The new scheme (7865 reversible reactions and 1975 species) yields improved model predictions of concentration profiles measured earlier in a jet-stirred reactor, and also represents fairly well the present experimental data over the entire range of conditions of this study. Sensitivity analyses and reaction path analyses were used to rationalize the results.     

Performance of miniaturized direct methanol fuel cell (DMFC) devices using micropump for fuel delivery

A fuel cell is a device that can convert chemical energy into electricity directly. Among various types of fuel cells, both polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs) can work at low temperature (<80 °C). Therefore, they can be used to supply power for commercial portable electronics such as laptop computers, digital cameras, PDAs and cell phones. The focus of this paper is to investigate the performance of a miniaturized DMFC device using a micropump to deliver fuel. The core of this micropump is a piezoelectric ring-type bending actuator and the associated nozzle/diffuser for directing fuel flow. Based on the experimental measurements, it is found that the performance of the fuel cell can be significantly improved if enough fuel flow is induced by the micropump at anode. Three factors may contribute to the performance enhancement including replenishment of methanol, decrease of diffusion resistance and removal of carbon dioxide. In comparison with conventional mini pumps, the size of the piezoelectric micropump is much smaller and the energy consumption is much lower. Thus, it is very viable and effective to use a piezoelectric valveless micropump for fuel delivery in miniaturized DMFC power systems.     

Diesel fuel processor for PEM fuel cells: Two possible alternatives (ATR versus SR)

There are large efforts in exploring the on-board reforming technologies, which would avoid the actual lack of hydrogen infrastructure and related safety issues. From this view point, the present work deals with the comparison between two different 10 kW_e fuel processors (FP) systems for the production of hydrogen-rich fuel gas starting from diesel oil, based respectively on autothermal (ATR) and steam-reforming (SR) process and related CO clean-up technologies; the obtained hydrogen rich gas is fed to the PEMFC stack of an auxiliary power unit (APU). Based on a series of simulations with Matlab/Simulink, the two systems were compared in terms of FP and APU efficiency, hydrogen concentration fed to the FC, water balance and process scheme complexity. Notwithstanding a slightly higher process scheme complexity and a slightly more difficult water recovery, the FP based on the SR scheme, as compared to the ATR one, shows higher efficiency and larger hydrogen concentration for the stream fed to the PEMFC anode, which represent key issues for auxiliary power generation based on FCs as compared, e.g. to alternators.     

Catalytic hydrogen/oxygen reaction assisted the proton exchange membrane fuel cell (PEMFC) startup at subzero temperature

Fuel cells for automobile application need to operate in a wide temperature range including freezing temperature. However, the rapid startup of a proton exchange membrane fuel cell (PEMFC) at subfreezing temperature, e.g., −20 °C, is very difficult. A cold-start procedure was developed, which made hydrogen and oxygen react to heat the fuel cell considering that the FC flow channel was the characteristic of microchannel reactor. The effect of hydrogen and oxygen reaction on fuel cell performance at ambient temperature was also investigated. The electrochemical characterizations such as I–V plot and cyclic voltammetry (CV) were performed. The heat generated rate for either the single cell or the stack was calculated. The results showed that the heat generated rate was proportional to the gas flow rate when H₂ concentration and the active area were constant. The fuel cell temperature rose rapidly and steadily by controlling gas flow rate.     

Mechanical performance of reactive-air-brazed (RAB) ceramic/metal joints for solid oxide fuel cells at ambient temperature

Mechanical integrity of the sealants in planar SOFC stacks is a key prerequisite for reliable operation. In this respect joining with metals rather than brittle glass-ceramics is considered to have advantages. Hence, as one of the joining solutions for SOFCs of planar design, reactive air brazing of ceramic cells into metallic frames gains increasing interest.Fracture experiments are carried out to characterize fracture energy and failure mechanisms of silver-based reactive-air-brazes, used for joining the zirconia electrolytes of anode supported planar cells with metallic Crofer22APU frames. The specimens are mechanically tested in notched beam bending geometry. In-situ observation in optical and SEM resolution reveals specific failure mechanisms. The influence of braze formulation and associated interfacial reactions on the crack path location is addressed. Discussion of the results focuses in particular on the role of oxide scale formation.     

机车柴油机燃油系统低烧二号工程改造方案的探讨

1引言大同地处北方内陆,具有霜期长,气候变化复杂,温差大的气候特点.因此,机车随着季节变化要更换不同标号的燃油,夏季使用5号、0号柴油,冬季使用-10号、-20号及-35号柴油.由于相邻两种标号柴油的价格每吨相差150～300元,如果机车在整个冬季使用高标号的燃油,成本就会大大增加.为进一步落实资产经营责任制,降低生产经营成本,大同机务段在低烧一号的基础上,提出再低烧一个标号的燃油,即冬季由-35号燃油改用-10号燃油.为保证实行低烧二号后机车燃油在冬季不析蜡,在夏季油温不会过高,保证机车正常工作,需要对机车燃油预热管路进行改造,以保证机车燃油的正常工作温度.     

Exergy analysis of an integrated fuel processor and fuel cell (FP–FC) system

Fuel cells have great application potential as stationary power plants, as power sources in transportation, and as portable power generators for electronic devices. Most fuel cells currently being developed for use in vehicles and as portable power generators require hydrogen as a fuel. Chemical storage of hydrogen in liquid fuels is considered to be one of the most advantageous options for supplying hydrogen to the cell. In this case a fuel processor is needed to convert the liquid fuel into a hydrogen-rich stream. This paper presents a second-law analysis of an integrated fuel processor and fuel cell system. The following primary fuels are considered: methanol, ethanol, octane, ammonia, and methane. The maximum amount of electrical work and corresponding heat effects produced from these fuels are evaluated. An exergy analysis is performed for a methanol processor integrated with a proton exchange membrane fuel cell, for use as a portable power generator. The integrated FP–FC system, which can produce 100 W of electricity, is simulated with a computer model using the flow-sheeting program Aspen Plus. The influence of various operating conditions on the system efficiency is investigated, such as the methanol concentration in the feed, the temperature in the reformer and in the fuel cell, as well as the fuel cell efficiency. Finally, it is shown that the calculated overall exergetic efficiency of the FP–FC system is higher than that of typical combustion engines and rechargeable batteries.     

A parametric study of the direct formic acid fuel cell (DFAFC) performance and fuel crossover

The effect of formic acid concentration (2–20 M), operating temperature (30–70 °C), and relative humidity (RH 40–90%) on the direct formic acid fuel cell (DFAFC) performance and fuel crossover were studied. In addition, air and oxygen were used to investigate the effect of oxidant flow rate on DFAFC performance and fuel crossover by operating the DFAFC under three modes of reactant supply: passive, semi passive (oxidant supplied), and active (both oxidant and fuel supplied). Fuel crossover was determined by measuring the percentage of exhausted carbon dioxide (CO₂) at the cathode using a CO₂ analyzer, from which the equivalent formic acid crossover flux was calculated. The results indicate that the DFAFC performance and fuel crossover were affected by formic acid concentration, temperature, humidity, oxidant flow rate, and the mode of operation. Optimums of these operating parameters were established for obtaining high performance of the DFAFC. The relationships between these parameters and the performance and fuel crossover of the DFAFC are discussed in this paper.     

Performance of plug flow microbial fuel cell (PF-MFC) and complete mixing microbial fuel cell (CM-MFC) for wastewater treatment and power generation

Two flow patterns (plug flow (PF) and complete mixing (CM)) of microbial fuel cells (MFCs) with multiple anodes–cathodes were compared in continuous flow mode for wastewater treatment and power generation. The results indicated that PF-MFCs had higher power generation and columbic efficiency (CE) than CM-MFCs, and the power generation varied along with the flow pathway in the PF-MFCs. The gradient of substrate concentrations along the PF-MFCs was the driving force for the power generation. In contrast, the CM-MFCs had higher wastewater removal efficiency than PF-MFCs, but had lower power conversion efficiency and power generation. This work demonstrated that MFC configuration is a key factor for enhancing power generation and wastewater treatment.     

Ni-samaria-doped ceria (Ni-SDC) anode-supported solid oxide fuel cell (SOFC) operating with CO

The performance of nickel-samaria-doped ceria (Ni-SDC) anode-supported cell with CO-CO₂ feed was evaluated. The aim of this work is to examine carbon formation on the Ni-SDC anode when feeding with CO under conditions when carbon deposition is thermodynamically favoured. Electrochemical tests were conducted at intermediate temperatures (550–700 °C) using 20 and 40% CO concentrations. Cell operating with 40% CO at 600–700 °C provided maximum power densities of 239–270 mW cm^?2, 1.5 times smaller than that achieved with humidified H₂. Much lower maximum power densities were attained with 20% CO (50–88 mW cm^?2). Some degradation was observed during the 6 h galvanostatic operation at 0.1 A cm^?2 with 40% CO fuel at 550 °C which is believed due to the accumulation of carbon at the anode. The degradation in cell potential occurred at a rate of 4.5 mV h^?1, but it did not lead to cell collapse. EDX mapping at the cross-section of the anode revealed that carbon formed in the Ni-SDC cell was primarily deposited in the anode section close to the fuel entry point. Carbon was not detected at the electrolyte-anode interface and the middle of the anode, allowing the cell to continue operation with CO fuel without a catastrophic failure.     

Hydrogen and fuel cell activities at UNIDO-ICHET

To place hydrogen energy usage into proper perspective, International Center for Hydrogen Energy Technologies (ICHET) has been implementing measures to demonstrate potential benefits of the “hydrogen and fuel cell systems” in developing countries. Demonstration of technologies is the most important aspect of ICHET vision for the formation of an industry in the developing world. ICHET has embarked on a series of educational and laboratory activities designed to increase the knowledge and awareness of students and advanced researchers concerning hydrogen energy technologies. The state of the art fuel cell laboratory is available for joint technology development and demonstration activities. Internship activities facilitate knowledge transfer, exchange of information at regional, national and international levels and involve academics, researchers, experts and service providers. Collaboration is a key part of the organizational strategy for joint projects, funding and trainings in the field of hydrogen and fuel cells.     

Investigations of direct methanol fuel cell (DMFC) fading mechanisms

In this report, we present the microscopic investigations on various fading mechanisms of a direct methanol fuel cell (DMFC). High energy X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), energy dispersive X-ray spectroscopy (EDX), and Raman spectroscopic analysis were applied to a membrane-electrode-assembly (MEA) before and after fuel cell operation to figure out the various factors causing its fading. High energy XRD analysis of the fresh and faded MEA revealed that the agglomeration of the catalyst particles in the cathode layer of the faded MEA was more significant than in the anode layer of the faded MEA. The XAS analysis demonstrated that the alloying extent of Pt (J_Pt) and Ru (J_Ru) in the anode catalyst was increased and decreased, respectively, from the fresh to the faded MEA, indicating that the Ru environment in the anode catalyst was significantly changed after the fuel cell operation. Based on the X-ray absorption edge jump measurements at the Ru K-edge on the anode catalyst of the fresh and the faded MEA it was found that Ru was dissolved from the Pt-Ru catalyst after the fuel cell operation. Both the Ru K-edge XAS and EDX analysis on the cathode catalyst layer of the faded MEA confirms the presence of Ru environment in the cathode catalyst due to the Ru crossover from the anode to the cathode side. The changes in the membrane and the gas diffusion layer (GDL) after the fuel cell operation were observed from the Raman spectroscopy analysis.     

微藻生产生物燃料及其技术进展

一引言 据介绍,目前制约生物柴油发展的难题,主要是原料昂贵、来源不稳定.由于各国多采用油料植物、粮食作物等原料,成本高、生长周期长并受环境限制,因此生物柴油的价格远高于传统柴油.选取合适的、低成本油脂资源来发展和生产生物柴油成为各国的研究热点.