Showing papers on "Alcohol fuel published in 2019"

Nanocatalysts for Electrocatalytic Oxidation of Ethanol.

Abstract: The use of ethanol as a fuel in direct alcohol fuel cells depends not only on its ease of production from renewable sources, but also on overcoming the challenges of storage and transportation. In an ethanol-based fuel cell, highly active electrocatalysts are required to break the C-C bond in ethanol for its complete oxidation at lower overpotentials, with the aim of increasing the cell performance, ethanol conversion rates, and fuel efficiency. In recent decades, the development of wet-chemistry methods has stimulated research into catalyst design, reactivity tailoring, and mechanistic investigations, and thus, created great opportunities to achieve efficient oxidation of ethanol. In this Minireview, the nanomaterials tested as electrocatalysts for the ethanol oxidation reaction in acid or alkaline environments are summarized. The focus is mainly on nanomaterials synthesized by using wet-chemistry methods, with particular attention on the relationship between the chemical and physical characteristics of the catalysts, for example, catalyst composition, morphology, structure, degree of alloying, presence of oxides or supports, and their activity for ethanol electro-oxidation. As potential alternatives to noble metals, non-noble-metal catalysts for ethanol oxidation are also briefly reviewed. Insights into further enhancing the catalytic performance through the design of efficient electrocatalysts are also provided.

Glycerol Electro-Oxidation in Alkaline Media and Alkaline Direct Glycerol Fuel Cells

Abstract: The low price, highly active triol structure, high volumetric energy density, simple storage and environment-friendly properties make glycerol a promising fuel for an alkaline direct alcohol fuel cell (ADAFC). Unlike other ADAFCs, alkaline direct glycerol fuel cells (ADGFCs) can be used either to generate only energy (the common use of fuel cells) or to produce both energy and valuable chemicals. This work presents an overview of catalysts for glycerol oxidation in alkaline media, and their use in ADGFCs. A particular attention was paid to binary and ternary catalysts able both to increase the selectivity to valuable C3 glycerol oxidation products, reducing the C–C bond cleavage, and simultaneously to enhance glycerol conversion.

An Overview of the Influence of Biodiesel, Alcohols, and Various Oxygenated Additives on the Particulate Matter Emissions from Diesel Engines

Abstract: Rising pollution levels resulting from vehicular emissions and the depletion of petroleum-based fuels have left mankind in pursuit of alternatives. There are stringent regulations around the world to control the particulate matter (PM) emissions from internal combustion engines. To this end, researchers have been exploring different measures to reduce PM emissions such as using modern combustion techniques, after-treatment systems such as diesel particulate filter (DPF) and gasoline particulate filter (GPF), and alternative fuels. Alternative fuels such as biodiesel (derived from edible, nonedible, and waste resources), alcohol fuels (ethanol, n-butanol, and n-pentanol), and fuel additives have been investigated over the last decade. PM characterization and toxicity analysis is still growing as researchers are developing methodologies to reduce particle emissions using various approaches such as fuel modification and after-treatment devices. To address these aspects, this review paper studies the PM characteristics, health issues, PM physical and chemical properties, and the effect of alternative fuels such as biodiesel, alcohol fuels, and oxygenated additives on PM emissions from diesel engines. In addition, the correlation between physical and chemical properties of alternate fuels and the characteristics of PM emissions is explored.

Comparative Analysis of the Combustion Stability of Diesel-Methanol and Diesel-Ethanol in a Dual Fuel Engine

Abstract: The co-combustion of diesel with alcohol fuels in a compression ignition dual fuel engine is one of the ways of using alternative fuels to power combustion engines. Scientific explorations in this respect should not only concern the combustion process in one engine cycle, which is most often not representative for a longer engine life, but should also include an analysis of multiple cycles, which would allow for indicating reliable parameters of engine operation and its stability. This paper presents experimental examinations of a CI engine with a dual fuel system, in which co-combustion was performed for diesel and two alcohol fuels (methanol and ethanol) with energy contents of 20%, 30%, 40% and 50%. The research included the analysis of the combustion process and the analysis of cycle-by-cycle variation of the 200 subsequent engine operation cycles. It was shown that the presence and increase in the share of methanol and ethanol used for co-combustion with diesel fuel causes an increase in ignition delay and increases the heat release rate and maximum combustion pressure values. A larger ignition delay is observed for co-combustion with methanol. Based on changes in the coefficient of variation of the indicated mean effective pressure (COVIMEP) and the function of probability density of the indicated mean effective pressure (f(IMEP)), prepared for a series of engine operation cycles, it can be stated that the increase in the percentage of alcohol fuel used for co-combustion with diesel fuel does not impair combustion stability. For the highest percentage of alcohol fuel (50%), the co-combustion of diesel with methanol shows a better stability.

Use of alternative fuels in compression ignition engines: a review

Abstract: This paper reviews the results of various researchers from different countries who prepared biofuels from vegetable oils and animal fats. The performance and emission characteristics can be improved by blending with petrodiesel, changing the fuel injection parameters, adding oxygen-rich fuel additives and employing intake air oxygen enrichment methods. NOx emissions can be minimised by using exhaust gas recirculation techniques. From this review, it can be concluded that the use of biofuels as an alternative fuel for compression ignition engines improves the performance and emissions by adopting suitable combustion improvement methods.

Influence of fuel injection timing and nozzle opening pressure on a CRDI-assisted diesel engine fueled with biodiesel-diesel-alcohol fuel

Abstract: Waste frying oil (WFO) is used as a feedstock for biodiesel synthesis due to its worldwide availability and low cost. WFO has the drawback of higher free fatty acid (FFA) presence and higher viscosity that lead to choking of the injector and lower the engine performance respectively. Biodiesel was synthesis through transesterification process using sodium methoxide catalyst. The fuel modification and engine modification was adopted to increase the engine combustion, performance characteristics and reduce the emissions characteristics. In fuel modification, the blend quantity was varied from 0% to 100%. The blend has a mixture of above 75% of biodiesel, 5% of diesel and lesser than 20% of pentanol and hexanol content. In engine modification, the fuel injection timing (FIT) was varied from 19° to 27°CA bTDC in the range of 2°CA and nozzle opening pressure (NOP) varied from 200 to 600 bar in the range of 100 bar. The B90-D5-P5, B85-D5-P10, B90-D5-H5 and B85-D5-H10 blends were selected for engine study, remaining blends were eliminated because of lower calorific value and lower flash and fire point. The engine experiment was carried out at full load condition on a common rail direct injection (CRDI) system assisted diesel engine. The results showed that the B90-D5-H5 blend was obtained the maximum thermal efficiency of 35.4% at NOP of 500 bar and FIT of 27°CA bTDC. B85-D5-P10 blend has the minimum CO and smoke emission of 0.04% vol. and 1.517 FSN at NOP of 500 bar and FIT of 27°CA bTDC respectively. The minimum UBHC and maximum NO emission of 10 and 1946 ppm was obtained in B85-D5-P10 blend at NOP of 600 bar and FIT of 27°CA bTDC respectively. The B90-D5-H5 blend has obtained the maximum heat release rate of 44.68 J/°CA at NOP of 500 bar and FIT of 27°CA bTDC. Thus, this research work was discusses the feasibility of recommending biodiesel-diesel-alcohol fuel to fulfill the future energy demands.

Passive direct alcohol fuel cell using methanol and 2-propanol mixture as a fuel

Abstract: This article examines the effect of addition of small concentration of 2-propanol on the direct methanol fuel cell (DMFC) in passive mode. The different concentration ratio of the alcohol mixture (methanol +2-propanol) is used with constant methanol concentration and by varying 2-propanol concentration in the solution. The new passive direct alcohol fuel cell (DAFC) performance with different alcohol concentration ratio (ACR) has been compared with conventional passive DMFC. The cyclic voltammetry (CV) test, polarization test, and electrochemical impedance spectroscopy (EIS) are carried out to complete the different aspect of the cell performance. The result shows that DAFC with different ACR yields the better performance than the conventional passive DMFC. In this study, the passive DAFC at 1:0.5 ACR shows the optimum cell performance.

Auto Ignition Study of Methane and Bio Alcohol Fuel Blends

Abstract: Methane (CH4) and bio alcohols have different ignition properties. These have been extensively studied and the resulting experimental data have been used to validate chemical kinetic models. Methane is the main component of natural gas, which is of interest because of its relative availability and lower emissions compared to other hydrocarbon fuels. Given growing interest in fuel-flexible systems, there can be situations in which the combustion properties of natural gas need to be modified by adding biofuels such as bio alcohols. This can occur in dual-fuel internal combustion engines or gas turbines with dual-fuel capabilities. The combustion behavior of such blends can be understood by studying the auto ignition properties in fundamental combustion experiments. Studies of the ignition of such blends are very limited in the literature. In this work, the auto ignition of methane and bio alcohol fuel blends is investigated using a shock tube facility. The chosen bio alcohols are ethanol (C2H5OH) and n-propanol (NC3H7OH). Experiments are carried out at 3 atm and 10 atm for stoichiometric and lean mixtures of fuel, oxygen, and argon. The ignition delay times of the pure fuels are first established at conditions of constant oxygen concentration and comparable pressures. The ignition delay times of blends with 50% methane are then measured. The pyrolysis kinetics of the blends is further explored by measuring CO formation during pyrolysis of the alcohol and methane–alcohol blends. The resulting experimental data are compared with the predictions of selected chemical kinetic models to establish the ability of these models to predict the disproportionate enhancement of methane ignition by the added alcohol.

Numerical Investigation of Methanol Ignition Sequence in an Optical PPC Engine with Multiple Injection Strategies

Abstract: Methanol is a genuine candidate on the alternative fuel market for internal combustion engines, especially within the heavy-duty transportation sector. Partially premixed combustion (PPC) engine concept, known for its high efficiency and low emission rates, can be promoted further with methanol fuel due to its unique thermo-physical properties. The low stoichiometric air to fuel ratio allows to utilize late injection timings, which reduces the wall-wetting effects, and thus can lead to less unburned hydrocarbons. Moreover, combustion of methanol as an alcohol fuel, is free from soot emissions, which allows to extend the operation range of the engine. However, due to the high latent heat of vaporization, the ignition event requires a high inlet temperature to achieve ignition event. In this paper LES simulations together with experimental measurements on an heavy-duty optical engine are used to study methanol PPC engine. After a successful calibration of the pressure trace in terms of required intake temperature and combustion model, the optical natural luminosity data is used to validate prediction of ignition kernel and vapor penetration length. Moreover, it is shown that the inlet temperature requirement is reduced by 47 K degrees when applying multiple injection strategy. Changing the injection strategy also affects the average temperature of combustion and thus the emissions rates. Additionally, an ignition sequence analysis is performed to identify the mode of combustion and the heat release (HR) distribution depending on the local equivalence ratio, recognizing characteristics of PPC regime. Based on this analysis, a conceptual heat distribution model for PPC engine and other low temperature combustion (LTC) engine concepts is proposed. (Less)

Chapter 4:Electrochemical Reforming of Alcohols

Abstract: With the emergence of the hydrogen economy, an intense search for economical sources of hydrogen is mandatory. In this sense, the electrochemical reforming of alcohols in proton or alkaline exchange membrane electrolysis cells has emerged as a solid alternative for hydrogen production in contrast to water electrolysis. The main attraction of this technology is the lower theoretical energy demand ascribed to the alcohol vs. water electro-oxidation. Methanol, ethanol, and, recently, glycerol and ethylene glycol are the most extensively used alcohols because they are obtained from environmentally sustainable processes. Electrochemical reforming of alcohols faces similar challenges as direct alcohol fuel cells. The development of active electrocatalysts for alcohol electro-oxidation is crucial for the success of electrochemical reforming. Thus, this chapter is devoted to the state-of-the-art electrocatalysts for alcohol oxidation and their application in electroreformers, both in acidic medium, in which Pt-based materials appear to be the most active, and alkaline medium, in which a wider spectrum of metals has been proposed successfully. In this sense, Pd-based electrocatalysts are considered competitive in comparison to Pt. Although significant advances have been achieved, there is still room for improvements, with the incentive of making this technology more competitive.

Analysis of Higher Alcohol Fuel Blends for IC Engine—A Review

Abstract: Higher alcohols like propanol and butanol have some significant advantages over lower alcohols like Methanol and Ethanol. Higher alcohols in engine resting better engine performance due to their lower heating value. The blending of Propanol and butanol is between the ratio of 5–20% with petrol and diesel in SI and CI engines also reduces the various emissions which effect the environment and improves spray characteristics. Butanol is thus not only a promising alternative fuel for gasoline but also a possible replacement for bioethanol as a fuel for internal combustion engines for transportation. There is a lack of literature review study on using higher alcohols like propanol and butanol with different blend ratios with diesel and petrol. The main objective of this paper is to analyze the performance of an IC engine using higher alcohols and its blend as a fuel. The study in this review papers to find out effect on engine parameters and various exhaust emission at different blends ratio. This review paper will help in critical areas to address research gaps on higher alcohols as a fuel in the IC engine.

Alcoholic Fuels in Diesel Engines. Methanol, Ethanol and Butanol

Abstract: On a modified diesel engine at the Institute for Powertrains and Automotive Technology at the Vienna University of Technology, fuel-specific combustion processes are being developed and analysed regarding their feasibility, efficiency and emissions. This article handles the operation of a diesel engine with bio-alcohols. The investigated fuels are methanol, ethanol and butanol. Due to the very low cetane number of these alcohols, their usage is normally assumed with spark ignition engines but not with a compression ignition engine. However, there are technical possibilities for alcohol fuel utilization in a diesel engine: 1) small amounts of the alcohol may be added to the conventional diesel fuel and 2) the diesel engine may be modified to operate in a dual fuel mode, whereas the alcoholic fuel is fed into the intake manifold and the diesel is directly injected into the combustion chamber. The addition of 10 or 20 vol% alcohol to the diesel fuel results in a significant reduction in soot emissions, especially at low loads. No significant differences to diesel reference operation are determined when operating with alcohol-diesel blends. By supplying alcohols into the intake manifold, depending on the operating point, substitution potentials of up to 85 % energy share can be achieved before unwanted combustion phenomena prevent a further increase of the alcohol amount. At higher loads within this operation mode the efficiency is increased by almost 2 % points. The observed strong decrease in particle mass and count allows a further reduction of the nitrogen oxide emissions.