Oxygen storage capacity of substituted YBaCo4O7+δ oxygen carriers

Depletion of non-renewable energy sources are at elevated manner due to the rapid growth of industrialization and transportation sector in last few decades and leads to further energy demand. Biodiesels especially second-generation fuels from non-edible oil resources are alternate sources for replacement of diesel fuel in CI engines due to their considerable environmental benefits. In the present work, non-edible feedstock of Calophyllum inophyllum seed oil (tamanu oil) is used for biodiesel production. Transesterification method is used for preparation of biodiesel in the existence of methanol with NaOH as catalyst. The copper nanoparticles are synthesized by electrochemical method, and it is characterized by using X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). XRD and SEM results confirm the presence of copper nanoparticle and size of around 30 nm. This paper aims to investigate the effects of the copper additive nanoparticles with biodiesel blends on the engine performance, combustion and emission characteristics of single-cylinder direct-injection diesel engine and compared that with diesel fuel. The results showed that the addition of nano-additives enhances brake thermal efficiency and reduces specific fuel consumption compared to biodiesel blends but slightly lower than diesel. Combustion characteristics also are enhanced by improved oxidation reaction inside the combustion chamber which resulted in higher heat release rate. The emissions of HC, NO_x and O₂ are significantly reduced for nano-additive blends compared to diesel but increased CO₂ emission was observed. It is noticed that higher CO₂ emission and substantial reduction of unused O₂ emissions from engine fueled with nano-additive are evident for enhanced oxidation and better combustion. Energy and exergy analysis of the diesel engine is carried out to estimate the effect of using nanoparticle additive with biodiesel.

     

Effects of equivalence and fuel ratios on combustion characteristics of an RCCI engine fueled with methane/n-heptane blend

Rising fuel costs and efforts for reducing greenhouse gases have led researchers to propose optimized models of combustion which have high efficiency and low emissions. Reactivity controlled compression ignition (RCCI) engines are attractive due to their high efficiency and low NO_x and soot emissions over a wide range of operating conditions. In this study, methane and n-heptane are used as low and high reactive fuels, respectively, to create suitable fuel stratification within the cylinder. Modeling is carried out by AVL FIRE coupled with a chemical kinetics solver to investigate the effects of fuel ratio, initial temperature and equivalence ratio on the combustion performance and emission characteristics. Methane/n-heptane ratios are varied according to the energy ratio of each fuel while total input energy and total equivalence ratios are fixed. By increasing methane energy ratio from 65% to 85% in the constant intake temperature and pressure, the mixture Octane number increases, which would lead to an increase in ignition delay up to 5 crank angles. As a result, IMEP would be enhanced and also NO_x emission decreases because of lower combustion temperature. By increasing intake temperature, the maximum in-cylinder pressure, heat release rate and NO_x emission would increase significantly while soot emission decreases, and also ringing intensity increases up to 10%. On the other hand, increasing intake temperature reduces volumetric efficiency; as a result, IMEP is reduced by 11%. Also by increasing equivalence ratio from 0.35 to 0.55 in a constant energy ratio, noticeable growth in the maximum amount of pressure and temperature could be achieved; consequently, NO_x emission would increase significantly, IMEP increases by 43%, and ISFC decreases by 30%. The results indicate that these parameters have significant effects on the heavy-duty RCCI engine performance and emissions.

     

氨能源作为清洁能源的应用前景

合成氨是一种成本低廉的化工原料,具有较高能量密度和辛烷值、易于压缩储运、燃烧不产生CO2等优点,是一种应用前景广泛的新型清洁能源。氨既可替代汽油、柴油等化石燃料,为汽车发动机直接提供清洁燃料,也可以经催化分解制取氢气,为车载燃料电池提供安全氢气。作为传统石油燃料的理想替代品,氨为解决环境污染和能源短缺问题提供了新的燃料选择。本文主要从发动机燃料和燃料电池原料两方面,介绍氨用于汽车动力源的优越性和可操作性,以及国内外相关研究进展;集中分析了氨分解制氢的催化剂体系的研究进展和局限性,以及合成氨的研究现状。     

Effect of Experimental Variables on the Combustion Characteristics of Water-in-Diesel Emulsion Fuels

Water-in-diesel (W/D) emulsion fuels were prepared through an ultrasonic processor by using high energy emulsification method. Accordingly, the physical and chemical properties were analyzed. A decrease in viscosity was found in the emulsion fuel in contrast to the neat diesel which signifies the enhanced fluidity of the fuel. The emulsion fuel was then used to carry combustion tests in an internal combustion engine. A decrease in exhaust temperature was observed when a high surfactant to water ratio was used, which lead to minimal heat loss. As water is emulsified with diesel, effectiveness of combustion is improved rather than neat diesel fuel. It was also explored that the addition of water-in-diesel is influential in terms of reduction in exhaust gas emission such as carbon dioxide, carbon monoxide, ammonia from the internal combustion engine. Therefore, this type of emulsion fuel would be a useful contribution in the fuel economy, but also in making it environmentally friendly since diesel fuel is now considered one of the leading fuels causing ecological contamination.     

乙醇/柴油混合燃料的相溶性及对发动机性能影响的研究

利用助溶剂解决乙醇/柴油的相溶性问题，讨论了混合燃料中乙醇和助溶剂添加量对相溶性的影响，并使用助溶剂体积分数为1.5%、乙醇体积分数分别为5%、10%、15%的混合燃料及 20号纯柴油（分别表示为E5、E10、E15和 E0）在发动机台架上进行了性能和排放试验。研究结果表明，柴油的烃组成是决定相分离温度的决定性因素；对全部测试油品，乙醇体积分数在10%、助溶剂添加体积分数为1.5%时，混合燃料相溶性较好。台架试验显示，随着混合燃料中乙醇掺烧比例的增加，发动机的燃油消耗率逐渐增加，而发动机的额定功率和最大扭矩逐渐降低，但最大扭矩降低的幅度较小；此外，随着乙醇掺烧比例的增加，CO比排放量减少，HC、NOx和PM的比排放量逐渐增加，但NOx和PM的比排放量增加幅度不大。10%体积分数的乙醇添加量是乙醇/柴油的最佳掺烧比。     

Experimental study on combustion characteristics of diesel–hydrogen dual-fuel engine

As a clean and sustainable energy source, hydrogen is widely considered as an engine fuel by top researchers. In view of the fact that the uneven fuel mixture of diesel fuel deteriorated the combustion and emissions process, it is expected to adopt diesel and hydrogen dual-fuel combustion technology to optimize combustion and heat release of diesel engine. In this study, experiments are carried out on a diesel engine and the combustion characteristics of the engine with different hydrogen ratios (RH) are compared. It has been found that hydrogen addition is conducive to accelerate the heat release rate and improve the thermal efficiency. Specifically, compared with pure diesel conditions, the peak pressure increased by 7.7% and the cumulative heat release rate increased by 3.7% under the condition of RH of 20%. Moreover, although the effect on the ignition delay period is not clear, the higher RH brings about earlier heat release center and more cumulative heat release while enhancing the heat release of premixed combustion reducing the diffusion combustion and post-combustion.

     

Biofuel Combustion Chemistry: From Ethanol to Biodiesel

Biofuels, such as bio‐ethanol, bio‐butanol, and biodiesel, are of increasing interest as alternatives to petroleum‐based transportation fuels because they offer the long‐term promise of fuel‐source regenerability and reduced climatic impact. Current discussions emphasize the processes to make such alternative fuels and fuel additives, the compatibility of these substances with current fuel‐delivery infrastructure and engine performance, and the competition between biofuel and food production. However, the combustion chemistry of the compounds that constitute typical biofuels, including alcohols, ethers, and esters, has not received similar public attention. Herein we highlight some characteristic aspects of the chemical pathways in the combustion of prototypical representatives of potential biofuels. The discussion focuses on the decomposition and oxidation mechanisms and the formation of undesired, harmful, or toxic emissions, with an emphasis on transportation fuels. New insights into the vastly diverse and complex chemical reaction networks of biofuel combustion are enabled by recent experimental investigations and complementary combustion modeling. Understanding key elements of this chemistry is an important step towards the intelligent selection of next‐generation alternative fuels.     

Evacuating liquid coatings from a diffusive oblique fin in micro-/mini-channels

The present work emphasis on to estimate the theoretical findings of energy and exergy analysis of biodiesel fueled with diesel on variable compression ratio engine at various combinations of fuel blend at different compression ratios. This study aims to identify the optimum engine settings based on compression ratio and biodiesel blends. The engine is operated with methyl esters of rubber seed oil and its 20, 40, 60 and 80% blends with diesel on volume basis. The compression ratio is varied from 18:1 to 22:1 at five compression ratios at 80% load in 3.5 kW, 1500 rpm, single cylinder water-cooled direct injection engine. The variables analyzed are energy and exergy potential of fuel input, shaft work, cooling water, maximum pressure, heat release rate, exergy destruction, brake-specific energy consumption, brake thermal efficiency, second law efficiency, entropy generation, exhaust gas temperature and various emissions. It is observed that the combination of CR 20, B20 and B40 at 80% load gives a better performance in thermodynamic analysis of methyl esters of rubber seed oil blended with diesel in VCR engine.

     

Ethanol Fuel Production from Cassava as a Substitute for Gasoline

The potential in alcohols as fuel had for long being recognized by the early inventors of machines and engines, even before gasoline and the hydrocarbons became popular. In fact, Henry Ford, one of the pioneers in automobile manufacture, designed his equipment to run on ethanol. But since then, time has seen gasoline and other conventional fuels take the front seat in engine application. This article is an insight into the experiment carried out to produce fuel from cassava starch and the characterization to determine some of the fuel properties in comparison to gasoline. The choice of cassava for the production was based on its availability and ability to grow in almost all geographical regions in Nigeria. Experimental production gave a sample concentration of 87% corresponding to a yield of 0.534 cm³ of ethanol per gram of starch hydrolyzed while the sample characteristics for the latent heat of vaporization, heat of combustion, flash point, and density are 950 kJ/kg, 22133.7 kJ/kg, 17–20°C, and 0.825, respectively. The results obtained compared favorably with those of gasoline that the sample concentration.     

Ethanol

Ethanol can be directly blended with gasoline, reacted with isobutylene to form the oxygenated fuel additive ethyl tert-butyl ether (ETBE), or burned directly as a neat fuel. Blends of either ethanol or ETBE with gasoline force engines set for gasoline to run lean and can substantially reduce carbon monoxide emissions. ETBE also lowers the overall vapor pressure, thereby cutting back on smog-forming emissions. Neat ethanol further reduces smog formation since it has a low volatility, the photochemical reactivity of ethanol and its combustion products is low, and low levels of smog producing compounds are formed by ethanol combustion. Neat ethanol also offers good engine performance owing to its high heat of vaporization, high octane, and low flame temperature. Fermentation stoichiometry reveals that many feedstocks are expensive for fuels production even considering coproduct credits and ignoring conversion costs, whereas lignocellulosic feedstocks cost much less than their value. Furthermore, the quantities of lignocellulosics are projected to be ample even for neat ethanol production. Release of carbon dioxide during fermentation concentrates almost all the heat of combustion from the solid carbohydrate portion in liquid ethanol. Since the carbon dioxide released during production and use of ethanol is recycled during growth of biomass, ethanol utilization doesn’t contribute to the accumulation of carbon dioxide in the atmosphere and possible global warming.     

Automotive fuels and internal combustion engines: a chemical perspective

Commercial transportation fuels are complex mixtures containing hundreds or thousands of chemical components, whose composition has evolved considerably during the past 100 years. In conjunction with concurrent engine advancements, automotive fuel composition has been fine-tuned to balance efficiency and power demands while minimizing emissions. Pollutant emissions from internal combustion engines (ICE), which arise from non-ideal combustion, have been dramatically reduced in the past four decades. Emissions depend both on the engine operating parameters (e.g. engine temperature, speed, load, A/F ratio, and spark timing) and the fuel. These emissions result from complex processes involving interactions between the fuel and engine parameters. Vehicle emissions are comprised of volatile organic compounds (VOCs), CO, nitrogen oxides (NO(x)), and particulate matter (PM). VOCs and NO(x) form photochemical smog in urban atmospheres, and CO and PM may have adverse health impacts. Engine hardware and operating conditions, after-treatment catalysts, and fuel composition all affect the amount and composition of emissions leaving the vehicle tailpipe. While engine and after-treatment effects are generally larger than fuel effects, engine and after-treatment hardware can require specific fuel properties. Consequently, the best prospects for achieving the highest efficiency and lowest emissions lie with optimizing the entire fuel-engine-after-treatment system. This review provides a chemical perspective on the production, combustion, and environmental aspects of automotive fuels. We hope this review will be of interest to workers in the fields of chemical kinetics, fluid dynamics of reacting flows, atmospheric chemistry, automotive catalysts, fuel science, and governmental regulations.     

Determination of the alternative butanol/gasoline and butanol/diesel fuel blends heats of combustion by a heat-loss compensated semi-microcalorimeter

The heat of combustion (HOC) of butanol/gasoline and butanol/diesel fuel blends was systematically determined in a Parr 6725/6772 heat-loss compensated semi-microcalorimeter under controlled temperature and pressure conditions. A set of blends containing 15 and 30% of butanol, in mass fraction, was tested, and the results were compared to those obtained for pure ethanol, pure gasoline, pure diesel, and Brazilian commercial gasoline. In view of the high volatility of samples, the use of gelatin capsules was necessary to avoid evaporation losses during the critical step of sampling. Results evidenced that despite a slight energy reduction observed for all blends, HOC values remained quite close to those measured for gasoline and diesel, even when considering blends with 30% of butanol in mass fraction, which reduction does not exceed 8.5%. Compared to ethanol, a HOC up to 14.7% higher was achieved for butanol. The present work confirms that in mass fractions up to 30%, butanol can be satisfactorily blended with gasoline and diesel without causing major impacts on the fuel energy density and, more than that, can offer energy advantage compared to ethanol.

     

Derivative spectrophotometric analysis of benzophenone (as an impurity) in phenytoin

Background

Biomass and municipal solid waste offer sustainable sources of energy; for example to meet heat and electricity demand in the form of combined cooling, heat and power. Combustion of biomass has a lesser impact than solid fossil fuels (e.g. coal) upon gas pollutant emissions, whilst energy recovery from municipal solid waste is a beneficial component of an integrated, sustainable waste management programme. Concurrent combustion of these fuels using a fluidised bed combustor may be a successful method of overcoming some of the disadvantages of biomass (high fuel supply and distribution costs, combustion characteristics) and characteristics of municipal solid waste (heterogeneous content, conflict with materials recycling). It should be considered that combustion of municipal solid waste may be a financially attractive disposal route if a 'gate fee' value exists for accepting waste for combustion, which will reduce the net cost of utilising relatively more expensive biomass fuels.

Results

Emissions of nitrogen monoxide and sulphur dioxide for combustion of biomass are suppressed after substitution of biomass for municipal solid waste materials as the input fuel mixture. Interactions between these and other pollutants such as hydrogen chloride, nitrous oxide and carbon monoxide indicate complex, competing reactions occur between intermediates of these compounds to determine final resultant emissions.

Conclusions

Fluidised bed concurrent combustion is an appropriate technique to exploit biomass and municipal solid waste resources, without the use of fossil fuels. The addition of municipal solid waste to biomass combustion has the effect of reducing emissions of some gaseous pollutants.     

Biofuels–Renewable Energy Sources: A Review

Biodiesel is biodegradable and nontoxic, and it significantly reduces toxic and other emissions when burned as a fuel. The advantages of biodiesel as diesel fuel are its portability, ready availability, renewability, higher combustion efficiency, non-toxicity, higher flash point, and lower sulfur and aromatic content, higher cetane number, and higher biodegradability. The major disadvantages of biodiesel are its higher viscosity, lower energy content, higher cloud point and pour point, higher nitrogen oxide (NO_x) emissions, lower engine speed and power, injector coking, engine compatibility, high price, and greater engine wear. The technical disadvantages of biodiesel/fossil diesel blends include problems with fuel freezing in cold weather, reduced energy density, and degradation of fuel under storage for prolonged periods. The sources of biodiesel are vegetable oils and fats. The direct use of vegetable oils and/or oil blends is generally considered to be unsatisfactory and impractical for both direct injection and indirect type diesel engines because of their high viscosities and low volatilities injector coking and trumpet formation on the injectors, higher level of carbon deposits, oil ring sticking, and thickening and gelling of the engine lubricant oil, acid composition. Biodiesel is obtained by transesterifying triglycerides with methanol. A popular variation of the batch transesterification process which needs high alcohol/acid ratio (several separation problems and high corrosivity and toxicity) is the use of continuous stirred tank reactors in series. This continuous process is heterogeneous and is based on reactive distillation. The key factor is the selection of the right and effective solid catalyst which leads to reduction of energy consumption and investments at all.     

F-T柴油对电控高压共轨柴油机性能及排放影响的研究

在满足国Ⅲ排放的现代高压共轨柴油机上,研究了掺烧不同比例F-T柴油混合燃料对发动机性能和排放的影响。结果表明,随着掺烧比例的加大,发动机的动力性略有下降,在外特性上,与燃烧国Ⅲ柴油相比,燃用F-T柴油时,扭矩最大下降2.2%,而燃油消耗率最高下降7.1%,有效热效率提高了4.5%。在十三工况的排放上,碳氢化合物（HC）、氮氧化物（NO_{x）、一氧化碳（CO）和颗粒（PM）的比排放量较国Ⅲ柴油均有明星下降,其中尤以燃用F-T柴油下降的幅度最大,PM降低了25.5%、NOx降低了11.7%、HC降低了39.3%、CO降低了33.9%。F-T柴油是柴油机的优良替代燃料。}     

Electrochemical Determination of Organic Compounds in Automotive Fuels

This article critically reviews the electroanalytical methods devoted for the determination of organic compounds in automotive fuels that can range from contaminants to additives typically introduced into liquid biofuels and liquid fossil fuels. Contaminants such as aldehydes and ketones in bioethanol, free fatty acids and glycerol in biodiesel, and sulfur and nitrogen organic compounds in gasoline and diesel fuel, and additives such as colour markers and antioxidants added to fuels were determined by electroanalytical methods. Special focus is given to electrodes, electrochemical techniques, and sample preparation strategies. Future directions of research on electroanalysis of liquid fuels are presented.     

Performance study of palladium modified platinum anode in direct ethanol fuel cells: A green power source

The direct ethanol fuel cell is a green and renewable power source alternative to fossil fuels and produces less emissions compared to a combustion engine. Ethanol can be generated in great quantity from renewable resources like biomass through a fermentation process. Bio-generated ethanol is thus attractive fuel since growing crops for biofuels absorbs much of the carbon dioxide emitted into the atmosphere from the oxidation of ethanol. The platinum and palladium were co-deposited on graphite substrate by the galvanostatic technique and employed as anode catalyst for ethanol electrooxidation. The information on surface morphology, structural characteristics and bulk composition of the catalyst was obtained using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) spectroscopy. The cyclic voltammetry (CV) were used for the estimation of the electrochemically active surface area (ECSA) of the synthesized catalysts in alkaline medium. The CVs for ethanol oxidation revealed superior catalytic activity of Pt–Pd/C compared to Pd/C and Pt/C. The effect of OH^? on ethanol oxidation at Pt–Pd/C catalyst was studied using cyclic voltammetry, quasisteady-state polarization, chronoamperometry, and electrochemical impedance spectroscopy (EIS). The Pt–Pd/C catalyst shows good stability and enhanced electrocatalytic activity is ascribed to the synergistic effect of higher electrochemical surface area, preferred OH^? adsorption on the surface and palladium ad-atom contribution on the alloyed surface.     

Thermodynamical evaluation of usefulness of future hydrocarbon fuels for use in compression ignition engines

The paper discusses the issues of the influence of the fuel spray formation on the generation of self-ignition spots and the development of pre-flame processes in the cylinder of a model diesel engine. The investigations were carried out for a standard diesel fuel and two other types of fuel that were mixtures of ethanol, butanol, and diethylether in a variety of proportions. By applying optical methods of analysis, the authors determined the geometrical indexes of the injected fuel spray as well as fuel mass distribution in the longitudinal and transverse cross section of the fuel spray during the injection process. The location and number of the self-ignition spots in the combustion chamber were evaluated on the basis of a comparison under various conditions: in presence of the charge swirl and at the lack of it. Research conducted for the single-cylinder engine confirmed the possibility of the use of diesel-like fuels for compression ignition engines.

     

Direct methanol fuel cells for vehicular applications

Dramatic technological advances for the proton exchange membrane fuel cell have focused attention on this technology for motor vehicles. The fuel cell vehicles (FCVs) have the potential to compete with the petroleum-fueled internal combustion engine vehicles (ICEVs) in cost and performance while effectively addressing air quality, energy insecurity, and global warming concerns. Methanol being a liquid can be easily transported and can be supplied from the existing network of oil company distribution sites. Recently, combining improved catalysts with fuel cell engineering, it has been possible to overcome some of the difficulties that have frustrated previous research and development efforts in realizing a commercially viable direct methanol fuel cell. Direct methanol fuel cells (DMFCs) with power densities between 0.2 and 0.4 W/cm² at operational temperatures in the range 95–130 °C have been developed. These power densities are sufficient to suggest that stack construction is well worth while. This paper reviews recent advances and technical challenges in the field of DMFCs. Received: 27 May 1997 / Accepted: 25 November 1997     

Determination of sulphur in liquids obtained by thermal cracking of waste polymers and commercial fuels with different analytical methods

Low sulphur concentration in hydrocarbon products as fuels or lubricants is an important requirement for the high quality standards of refineries. A non-polarised energy dispersive X-ray fluorescence spectroscopy (EDXRFS) and sample combustion technique (ASTM D6428-99) was compared. A new application of energy dispersive X-ray spectrometry as analytical method for the determination of sulphur in fuels and fuel-like fractions was investigated. Low sulphur containing fuels and hydrocarbon mixtures obtained by thermal cracking of waste polymers were measured and the influence of C/H ratio on accuracy was studied. The concentration of sulphur in samples was measured with calibration graphs of different hydrocarbon matrices (commercial gasoline, diesel oil and white oil were used). Good correlation was observed between the different methods, but the correlation was depending on the characteristics of the matrices. Detection limits of 1.0 ppm, 1.1 ppm and 0.9 ppm were obtained for S in gasoline, diesel oil and white oil, respectively.