Showing papers on "Alcohol fuel published in 2017"

Alternative fuels for internal combustion engines

Abstract: This review paper covers potential alternative fuels for automotive engine application for both spark ignition (SI) and compression ignition (CI) engines. It also includes applications of alternative fuels in advanced combustion research applications. The representative alternative fuels for SI engines include compressed natural gas (CNG), hydrogen (H 2 ) liquefied petroleum gas (LPG), and alcohol fuels (methanol and ethanol); while for CI engines, they include biodiesel, di-methyl ether (DME), and jet propellent-8 (JP-8). Naphtha is introduced as an alternative fuel for advanced combustion in premixed charge compression ignition. The production, storage, and the supply chain of each alternative fuel are briefly summarized, and are followed by discussions on the main research motivations for such alternative fuels. Literature surveys are presented that investigate the relative advantages and disadvantages of these alternative fuels for application to engine combustion. The contents of engine combustion basically consist of the combustion process from spray development, air–fuel mixing characteristics, to the final combustion product formation process, which is analyzed for each alternative fuel. An overview is provided for alternative fuels together with summaries of engine combustion characteristics for each fuel, in addition to its current distribution status and future prospects.

A comprehensive review on performance, combustion and emission characteristics of biodiesel fuelled diesel engines

Abstract: Direct injection diesel engines are more popular in the automotive sector than spark ignition (SI) engines due to its fuel lean operation However, the demand of fossil fuel is rising day by day and hence the major fuel source of diesel engine, the petroleum based fuel, is depleting rapidly Many countries depend mainly on imported fossil fuels due to lack of fuel reserves and it has great impact on the economy In addition to this, the major concerns of diesel engine are its oxides of nitrogen and smoke emissions Therefore, for the past several decades extensive efforts are being made to search for alternate fuels to overcome the dependence on fossil fuel and environment pollution In this regard, several alternate fuels namely hydrogen, oxygenated fuels like alcohol fuels, dimethyl ether and biodiesel fuels etc, have been extensively analysed Recent studies show that biodiesel is one of the most promising alternate fuels for diesel engines because of its biodegradable, oxygenated, sulphur free and renewable characteristics Hence, it is getting the attention of researchers all over the world The blends of biodiesel with fossil diesel have many benefits like reduction in emissions, lower engine wear, lesser engine oil consumption and comparable thermal efficiency vis-a-vis diesel fuel Exhaustive experimental works have been carried out to analyse the suitability of biodiesel fuel as alternate fuel and to explore their advantages in diesel engines Hence, this paper is attempted to present a comprehensive review on the performance, combustion and emission characteristics of some important biodiesel fuels on diesel engines This comprehensive review on the published literature will be helpful to the researchers to understand the state-of-the-art technology of the biodiesel fuelled compression ignition engine

Effects of alternative fuels on the combustion characteristics and emission products from diesel engines: A review

Abstract: Diesel engines are the main source of rapidly-growing energy consumption worldwide. Diesel consumption is responsible for serious air pollution, which includes nitrogen oxides (NOx), hydrocarbon (HC), carbon monoxide (CO) emissions and some particulate matter (PM) discharged from the combustion chamber. In the past few decades, alternative fuels, such as alcohol, biodiesel, natural gas, and Di Methyl Ether (DME), have been used in diesel engines to reduce energy costs and environmental pollution. As a result of alternative fuels directives, an increasing number of diesel engines have adapted dual fuel blends, and an enormous amount of research is focused on new and inadequately studied combustion and emission profiles. Compared to conventional diesel fuel, the application of dual fuels would add new parameters to combustion and emission profiles for diesel vehicles worldwide. This review aims to reveal (1) Known and anticipated combustion characteristics and emissions products from dual fuels. (2) Toxic properties and the expected influence on engine performance. (3) Identifying promising alternative fuels for emissions control in compression combustion engines. The results presented herein will show a significant reduction of regular gas and PM emissions by the use of alcohol/diesel dual fuel, while unregulated emissions such as methanol, ethanol, acetaldehyde, formaldehyde, ketone, have increased compared to those from diesel fuel. PM emissions decreased significantly with the increase of alternative fuels, such as alcohols, natural gas, biodiesel and DME, while regular gaseous emissions varied depending on the type alternative fuel and the engine conditions. As one new and cleaner substitute for diesel engines, DME operation has a longer injection delay, lower maximum cylinder pressure, a lower ratio of pressure rise, and shorter ignition delay in comparison with diesel operation--the opposite of alcohol/diesel and dual fuels. This review evaluates the effects of some alternative fuels (alcohol, biodiesel, natural gas and Di Methyl Ether (DME)) on combustion characteristics and emission products from diesel engines to meet future emission regulations using alternative fuel.

Alcohol based automotive fuels from first four alcohol family in compression and spark ignition engine: A review on engine performance and exhaust emissions

Abstract: Alcohol fuels have some significant advantages over other alternative fuels, including the ability to work in existing engines as well as the capability to reduce greenhouse gas emissions. This paper analyses the performance and emissions of compression and spark ignition engine using of alcohol fuels from the first aliphatic alcohol family; methanol, ethanol, propanol and butanol. The literature relevant to methanol, ethanol, propanol and butanol was reviewed and summarized to demonstrate its viability as an alternative fuel. The fuel properties of methanol, ethanol, propanol and butanol present the most important properties that allow such fuels as suitable candidates as an alternative fuel for compression and spark ignition engines. The performance and engine emissions indicators such as brake torque, brake power, BTE, BSFC NOx, PM, CO, CO2, HC and soot have been evaluated regarding tone at diesel and gasoline fuels. The results showed that alcohol fuels give different results to engine performance and emissions. Surprisingly, some research yield favorable results to the alcohol as compared to neat diesel and gasoline fuels. It can be concluded that methanol, ethanol, propanol and butanol are capable of reducing harmful engine exhaust emissions, however,at the expense of lower engine performance characteristics.

Effects of physicochemical properties of biodiesel fuel blends with alcohol on diesel engine performance and exhaust emissions: A review

Abstract: In recent years, alternative fuel studies have been conducted thoroughly by researchers through their experimental work Depletion of fossil fuel raised the attention of researchers to investigate renewable energy sources such as biodiesel and alcohol There is a lack of literature review study on the viability of alcohol acting as additive in biodiesel-diesel fuel blends Thus, this review paper studies on the effects of various alcohol additives in biodiesel-diesel fuel blends on combustion behaviour, performance and emission characteristics of diesel engines The physicochemical properties of alcohol and biodiesel are rigorously discussed, in which they are the main factors in determining the quality of the blended fuel The aim of this paper is to identify the potential of alcohol fuel as an additive in the blended biodiesel and diesel fuel in correspond to the type of alcohol, blending ratio and engine operation conditions Wide range of results from previous research studies with different types of compression-ignition engine, different engine operation conditions and varieties of alcohol-biodiesel-diesel fuel blending ratios were collected in this literature review study Combustion behaviour such as coefficient of variations (COV), in-cylinder pressure, ignition delay, heat release rate and combustion duration are presented Low cetane number and high latent heat of vaporization of alcohol cause a longer ignition delay, produce higher rate of heat release and lower in-cylinder pressure when compared with that of diesel fuel Low density and viscosity of alcohol improve the spray characteristics and enhance air-fuel mixing process In terms of engine performance analysis, the presence of oxygen in alcohol fuel promotes a more complete combustion; hence, resulting in an increase of thermal efficiency In turn, emissions of carbon monoxide (CO), hydrocarbon (HC) and particulate matter (PM) are decreasing

Comprehensive overview on diesel additives to reduce emissions, enhance fuel properties and improve engine performance

Abstract: The present review investigates modification of diesel fuel formulation and development of a new model to enhance engine performance, improve fuel properties and reduce exhaust emissions. Emissions arising from the fuel can be controlled by blending an oxygenated fuel (renewable fuel) with the diesel fuel. The blending oxygenated fuels namely Methanol, Ethanol, and n-Butanol are examined in addition to their effects. This review paper studies the implication of different torques and various engine speeds. In some conditions, it can even cause an increase in the content of carbon monoxides (CO), carbon dioxide (CO2) and nitrogen oxides. This review showed that the engine speed has a negative effect on all of the air pollutants, so that increasing of the engine speed leads to reduction of the air pollutants. However, the engine load gives rise to most exhaust emissions. Adding the oxygenate fuels increases brake specific fuel consumption (BSFC), while brake thermal efficiency (BTE) decreases. In some researches, a nano-metal additive has been used in the fuel for improving the engine performance. In case of using the nano-metal additives to the diesel fuel (a nano-metal with small thermal conductivity coefficient), the engine performance is seen increased.

Effect of lower and higher alcohol fuel synergies in biofuel blends and exhaust treatment system on emissions from CI engine

Abstract: The present study deals with performance, emission and combustion studies in a single cylinder CI engine with lower and higher alcohol fuel synergies with biofuel blends and exhaust treatment system. Karanja oil methyl ester (KOME), widely available biofuel in India, and orange oil (ORG), a low carbon biofuel, were taken for this study, and equal volume blend was prepared for testing. Methanol (M) and n-pentanol (P) was taken as lower and higher alcohol and blended 20% by volume with KOME-ORG blend. Activated carbon-based exhaust treatment indigenous system was designed and tested with KOME-ORG + M20 and KOME-ORG + P20 blend. The tests were carried out at various load conditions at a constant speed of 1500 rpm. The study revealed that considering performance, emission and combustion studies, KOME-ORG + M20 + activated carbon are found optimum in reducing NO, smoke and CO2 emission. Compared to KOME, for KOME-ORG + M20 + activated carbon, NO emission is reduced from 10.25 to 7.85 g/kWh, the smoke emission is reduced from 49.4 to 28.9%, and CO2 emission is reduced from 1098.84 to 580.68 g/kWh. However, with exhaust treatment system, an increase in HC and CO emissions and reduced thermal efficiency is observed due to backpressure effects.

Advantages of ethanol–gasoline blends as fuel substitute for last generation Si engines

Abstract: The stringent international emission legislations and increasing demands for lesser fuel consumption and air pollutant emissions in urban environment necessitate substantial and effective plans to improve combustion efficiency of anthropogenic activities. For this reason, all the industrialized countries are energetically developing alternative fuel sources in order to reduce the harmful air emissions and to decrease the necessity of fossil fuel. In this context, ethanol can be used as an alternative fuel or an additive of gasoline owing to many advantages, above all the possibility to rise oxygen amount in the fuel (so reducing CO and HC exhaust emissions) and to stem the depletion of fossil fuels. Many studies have been carried out to evaluate the effects of ethanol combined with gasoline on engine performance and exhaust emissions. This article analyze prospect of fuel ethanol as an effective gasoline substitute, and examines comparative physicochemical properties of ethanol and gasoline and their effect on emissive behavior of SI engines. This article, then, creates a fundamental basis for further discussions and experimental activities on the last generation SI engines fuelled with ethanol/gasoline-blended fuels. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1173–1179, 2017

Composition-controllable synthesis of defect-rich PtPdCu nanoalloys with hollow cavities as superior electrocatalysts for alcohol oxidation

Abstract: Preparing defect-rich Pt-based nanocatalysts for alcohol fuel cell applications remains a huge challenge. Here, we introduce a facile, environmentally friendly, one-pot approach to synthesize trimetallic PtPdCu nanoalloys with hollow cavities and numerous defects, such as lower coordination atoms, corners, interior boundaries, lattice disorders and dislocations and twin boundaries. The as-synthesized Pt34Pd33Cu33 nanoalloys exhibit excellent electrocatalytic properties for alcohol oxidation in acidic medium. The peak current density of the Pt34Pd33Cu33 nanoalloys is, respectively, 2.2 times (for methanol), 1.2 times (for ethanol) and 2.1 times (for glycol) that on commercial Pt black. Furthermore, after 1000 cycles, the current density of the Pt34Pd33Cu33 nanoalloys is 2.4 times (for methanol), 1.8 times (for ethanol) and 3.0 times (for glycol) that on commercial Pt black.

Product Distributions and Efficiencies for Ethanol Oxidation in a Proton Exchange Membrane Electrolysis Cell

Abstract: Ethanol is an attractive fuel for direct alcohol fuel cells (DAFCs). In comparison with other organic fuels, ethanol has a high energy density. Therefore, direct ethanol fuel cells (DEFCs) are considered to be highly attractive power sources for electronic devices and vehicles. In addition, ethanol can be oxidized in an ethanol electrolysis cell (EEC) to produce hydrogen for use in fuel cells. Although ethanol has a high energy density and DEFCs have a high theoretical efficiency (98%), these are based on complete oxidation of ethanol to CO₂, while the main products from DEFCs and EECs are acetic acid and acetaldehyde. A good understanding of what happens during ethanol oxidation in fuel cell hardware is therefore a crucial step in the evolution of these technologies. It is particularly important in the development of new catalysts to improve cell efficiencies and performances by facilitating the complete oxidation of ethanol. The methods reported here provide information on the efficiency and product distribution for ethanol oxidation in a DEFC or EEC. They are based on polymer electrolyte membrane (PEM) fuel cell technology. In comparison with those reported in the literature, our methodologies are shown to have advantages over them by detecting the fuel itself and reaction products from both the anode and cathode exhausts. The amounts of ethanol consumed and acetic acid and acetaldehyde produced were determined by proton NMR spectroscopy while CO₂ was measured with a non-dispersive infrared CO₂ monitor. The efficiencies of these cells are dependent on the cell potential, crossover of ethanol, and stoichiometry of the ethanol oxidation reaction (i.e. the average number of electrons transferred per ethanol molecule). The stoichiometry of the EOR (ethanol oxidation reaction) was determined by using different methods in this work: an electrochemical method, analysis of the amount of ethanol consumed (ΔC) and from the product distribution (faradaic and chemical). It was found that the results from these methods were in a good agreement. In addition, the effects of fuel and product crossover were closely examined. It was shown that analysis of only the anode exhaust solution leads to an underestimation of ethanol and products due to crossover through the membrane to the cathode. To obtain accurate product distributions, the anode and cathode exhausts were combined. In addition, the chemical reaction between ethanol and oxygen that occurs in a DEFC was avoided by making measurement in an EEC with N₂ gas at the cathode. The stoichiometry, efficiency, and product distribution for ethanol electrolysis in fuel cell hardware has been determined at 80°C for various anodes prepared with commercial Pt/C, PtRu/C, and PtSn/C catalysts. Also, synergetic effects between these catalysts were studied by using mixed and bilayer electrodes. It was found that bilayer electrodes increased the overall efficiency of the cell by increasing the faradaic efficiency while maintaining high potential efficiency. An octahedral PtNi catalyst was prepared by using a literature method and tested in our system. In comparison to a Pt, this catalyst was shown to increase selectivity towards complete oxidation (to carbon dioxide) at low potentials and thereby increase efficiency. These results are contrary to those reported in the literature for this catalyst in a conventional electrochemical cell, and demonstrate the importance of the new methodologies in the evaluation and study of new catalysts for ethanol oxidation.

Process system engineering aspect of bio-alcohol fuel production from biomass via pyrolysis: An overview

Abstract: Due to depleting petroleum reserves and the environmental impact of fossil fuels, it is important to find alternative sources for transport fuels An alternative solution is bio-alcohol fuel, which has potential in the transport sector and in electricity generation Biomass-based sources offer the best solution for transitioning to liquid fuel because of its global availability and energetic gain Current fuel research and development addresses process engineering trends for improving bio-alcohol production in pyrolysis This paper addresses developments in modeling simulation, optimization and control systems related to bio-alcohol production The most promising solutions to bio-alcohol fuel production costs by the generation of valuable co-products are analyzed These findings are supported by heat and mass transfer in the production of bio-alcohol fuel as well as by economic analysis Finally, some concluding considerations on current and future research trends in the study of bio-alcohol are presented

Electrocatalytic reactions involved in low temperature fuel cells

Abstract: For a clean environment, low-temperature fuel cells are particularly important to power familiar devices, such as portable electronics (cell phones, computers, cam recorders, etc.) or electrical vehicles (buses, trucks, and individual cars). Among them, the alkaline fuel cell working at 80 °C with pure hydrogen, the proton exchange membrane fuel cell that can operate at temperatures ranging from ambient to 70–80 °C with hydrogen either produced by water electrolysis or by hydrocarbon reforming, and the direct alcohol fuel cell that realizes at higher temperatures (up to 120–150 °C) the direct electrooxidation of methanol or ethanol are particularly convenient. In these fuel cells, because of the relatively low working temperatures, the kinetics of the electrochemical reactions involved (fuel oxidation and oxygen reduction) is rather slow. Therefore, to improve the reaction kinetics, by a careful design of the electrode catalyst, it is necessary to determine detailed reactionmechanisms, where all the adsorbed species and intermediate products have been clearly identified. The use of purely electrochemical techniques is not at all sufficient to do it, and electrochemical methods have to be coupled with spectroscopic methods (infrared spectroscopy, mass spectroscopy, etc.) and analytical methods (gas chromatography, high-pressure liquid chromatography, radiotracers, etc.) in order to identify the different species involved and to evaluate their concentration or surface amount. After the establishment of the reaction mechanism, particularly the knowledge of the rate determining step, it is important to design suitable electrocatalysts able to activate preferentially the rate determining step.The various methods to prepare such catalysts are first presented. Then, the different physicochemical methods used to evaluate their properties and to determine the reaction mechanisms are discussed. Finally, the reaction mechanisms of the most important electrochemical reactions involved in low-temperature fuel cells, that is, the electrooxidation of hydrogen, carbon monoxide, methanol, and ethanol and the electroreduction of oxygen, have been established.

Efficacy of Add-On Hydrous Ethanol Dual Fuel Systems to Reduce NOx Emissions From Diesel Engines

Abstract: Aftermarket dual-fuel injection systems using a variety of different fumigants have been proposed as alternatives to expensive after-treatment to control NOX emissions from legacy diesel engines. However, our previous work has shown that available add-on systems using hydrous ethanol as the fumigant achieve only minor benefits in emissions without recalibration of the diesel fuel injection strategy. This study experimentally re-evaluates a novel aftermarket dual-fuel port fuel injection (PFI) system used in our previous work, with the addition of higher flow injectors to increase the fumigant energy fraction (FEF), defined as the ratio of energy provided by the hydrous ethanol on a lower heating value (LHV) basis to overall fuel energy. Results of this study confirm our earlier findings that as FEF increases, NO emissions decrease, while NO2 and unburned ethanol emissions increase, leading to no change in overall NOX. Peak cylinder pressure and apparent rates of heat release are not strongly dependent on FEF, indicating that in-cylinder NO formation rates by the Zel’dovich mechanism remains the same. Through single zone modeling, we show the feasibility of in-cylinder NO conversion to NO2 aided by unburned ethanol. The modeling results indicate that NO to NO2 conversion occurs during the early expansion stroke where bulk gases have temperature in the range of 1150 -1250 K. This work conclusively proves that aftermarket dual fuel systems for fixed calibration diesel engines cannot reduce NOX emissions without lowering peak temperature during diffusive combustion responsible for forming NO in the first place. INTRODUCTION Diesel engines are known for reliability, durability, low manufacturing cost and high power density. Given their longevity, legacy diesels regulated to older emissions levels will continue to be used in practice for decades to come. New diesel engines have ~27% lower NOX emissions than engines of a decade ago [1] in part due to selective catalytic reduction (SCR) aftertreatment systems. Although aftertreatment is an effective method for reducing emissions, in-cylinder techniques are also attractive to reduce SCR urea dosing rate requirements or to possibly eliminate the need for NOX aftertreatment altogether. In-cylinder NO is primarily formed during combustion through a combination of chemical pathways including the extended Zel’dovich, prompt (Fenimore) and N2O mechanisms [2–4]. NO in diesel engines mainly arises through the thermally controlled Zel’dovich mechanism in lean to stoichiometric regions found near the periphery of the diffusive flame front. NO is oxidized to NO2 and concentrations “freeze” short of thermodynamic equilibrium soon after the end of injection and mixing of burned gases [5] in the expansion stroke. Low temperature combustion modes like dual fuel reactivity controlled compression ignition (RCCI) have been shown to simultaneously limit in-cylinder NOX and soot production over a wide speed and load range [6–8]. RCCI uses fumigation of a low reactivity fuel, like gasoline into the intake manifold and early direct injection of a high reactivity fuel like diesel to avoid high temperature NOX formation regions found in conventional diesel combustion. Various fumigants have been investigated for RCCI including hydrogen, gasoline, hydrous ethanol, and natural gas [9–14] and all have similar impacts on avoiding in-cylinder NOX formation. Although RCCI is an attractive method for in-cylinder emissions reduction, it must be implemented in new engines due to the requirement for significant modifications to engine hardware and software. To date, manufacturers have chosen to employ NOX aftertreatment like SCR to meet stringent emissions standards for new engines and rely less on advanced in-cylinder techniques like dual fuel RCCI. For legacy diesel engines regulated to older emissions standards, add-on SCR and lean NOX trap aftertreatment systems have been marketed to meet new in-use NOX regulations [15]. Dual fuel retrofit kits are available that also claim to reduce NOX emissions without aftertreatment while also substituting diesel fuel for lower carbon fuels like compressed natural gas or partially renewable ethanol [16,17]. These aftermarket systems incorporate a separate fuel system and fumigate the secondary fuel directly into the intake

Fundamentals of Electrochemistry with Application to Direct Alcohol Fuel Cell Modeling

Abstract: Fuel cell modeling is an inherently multiphysics problem. As a result, scientists and engineers trained in different areas are required to work together in this field to address the complex physicochemical phenomena involved in the design and optimization of fuel cell systems. This multidisciplinary approach forces researchers to become accustomed to new concepts. Electrochemical processes, for example, constitute the heart of a fuel cell. Accurate modeling of electrochemical reactions is therefore essential to successfully predict the performance of these devices. However, becoming familiar with the complex concepts of electrochemistry can be an arduous task for those who approach the study of fuel cells from fields other than chemical engineering. This process can extend over time and requires careful reading of many textbooks and papers, the most illuminating ones being hidden to the newcomer in a plethora of recent publications on the subject. The authors, who engaged in the study of fuel cells coming from the field of mechanical engineering, had to travel this road once and, with this contribution, would like to make the journey easier for those who come behind. As an illustrative example, the thermodynamic and electrochemical principles reviewed in this chapter are applied to a complex electrochemical system, the direct ethanol fuel cell (DEFC), reviewing recent work on this problem and suggesting future research directions.