Performance, emission and combustion characteristics of biodiesel fuelled variable compression ratio engine

Experiments has been carried out to estimate the performance, emission and combustion characteristics of a single cylinder; four stroke variable compression ratio multi fuel engine fuelled with waste cooking oil methyl ester and its blends with standard diesel. Tests has been conducted using the fuel blends of 20%, 40%, 60% and 80% biodiesel with standard diesel, with an engine speed of 1500 rpm, fixed compression ratio 21 and at different loading conditions. The performance parameters elucidated includes brake thermal efficiency, specific fuel consumption, brake power, indicated mean effective pressure, mechanical efficiency and exhaust gas temperature. The exhaust gas emission is found to contain carbon monoxide, hydrocarbon, nitrogen oxides and carbon dioxide. The results of the experiment has been compared and analyzed with standard diesel and it confirms considerable improvement in the performance parameters as well as exhaust emissions. The blends when used as fuel results in the reduction of carbon monoxide, hydrocarbon, carbon dioxide at the expense of nitrogen oxides emissions. It has found that the combustion characteristics of waste cooking oil methyl ester and its diesel blends closely followed those of standard diesel.     

Performance of jatropha oil blends in a diesel engine

Results are presented on tests on a single-cylinder direct-injection engine operating on diesel fuel, jatropha oil, and blends of diesel and jatropha oil in proportions of 97.4%/2.6%; 80%/20%; and 50%/50% by volume. The results covered a range of operating loads on the engine. Values are given for the chemical and physical properties of the fuels, brake specific fuel consumption, brake power, brake thermal efficiency, engine torque, and the concentrations of carbon monoxide, carbon dioxide and oxygen in the exhaust gases. Carbon dioxide emissions were similar for all fuels, the 97.4% diesel/2.6% jatropha fuel blend was observed to be the lower net contributor to the atmospheric level. The trend of carbon monoxide emissions was similar for the fuels but diesel fuel showed slightly lower emissions to the atmosphere. The test showed that jatropha oil could be conveniently used as a diesel substitute in a diesel engine. The test further showed increases in brake thermal efficiency, brake power and reduction of specific fuel consumption for jatropha oil and its blends with diesel generally, but the most significant conclusion from the study is that the 97.4% diesel/2.6% jatropha fuel blend produced maximum values of the brake power and brake thermal efficiency as well as minimum values of the specific fuel consumption. The 97.4%/2.6% fuel blend yielded the highest cetane number and even better engine performance than the diesel fuel suggesting that jatropha oil can be used as an ignition-accelerator additive for diesel fuel.     

Electrochemical study of composite materials for coal-based direct carbon fuel cell

The efficient conversion of solid carbon fuels into energy by reducing the emission of harmful gases is important for clean environment. In this regards, direct carbon fuel cell (DCFC) is a system that converts solid carbon directly into electrical energy with high thermodynamic efficiency (100%), system efficiency of 80% and half emission of gases compared to conventional coal power plants. This can generate electricity from any carbonaceous fuel such as charcoal, carbon black, carbon fiber, graphite, lignite, bituminous coal and waste materials. In this paper, ternary carbonate-samarium doped ceria (LNK-SDC) electrolyte has been synthesized via co-precipitation technique, while LiNiCuZnFeO (LNCZFO) electrode has been prepared using solid state reaction method. Due to significant ionic conductivity of electrolyte LNK-SDC, it is used in DCFC. Three types of solid carbon (lignite, bituminous, sub-bituminous) are used as fuel to generate power. The X-ray diffraction confirmed the cubic crystalline structure of samarium doped ceria, whereas XRD pattern of LNCZFO showed its composite structure.The proximate and ultimate coal analysis showed that fuel (carbon) with higher carbon content and lower ash content was promising fuel for DCFC. The measured ionic conductivity of LNK-SDC is 0.0998 Scm^?1 and electronic conductivity of LNCZFO is 10.1 Scm^?1 at 700 °C, respectively. A maximum power density of 58 mWcm^?2 is obtained using sub-bituminous fuel.     

Biodiesel production from inedible animal tallow and an experimental investigation of its use as alternative fuel in a direct injection diesel engine

In this study, a substitute fuel for diesel engines was produced from inedible animal tallow and its usability was investigated as pure biodiesel and its blends with petroleum diesel fuel in a diesel engine. Tallow methyl ester as biodiesel fuel was prepared by base-catalyzed transesterification of the fat with methanol in the presence of NaOH as catalyst. Fuel properties of methyl ester, diesel fuel and blends of them (5%, 20% and 50% by volume) were determined. Viscosity and density of fatty acid methyl ester have been found to meet ASTM D6751 and EN 14214 specifications. Viscosity and density of tallow methyl esters are found to be very close to that of diesel. The calorific value of biodiesel is found to be slightly lower than that of diesel. An experimental study was carried out in order to investigate of its usability as alternative fuel of tallow methyl ester in a direct injection diesel engine. It was observed that the addition of biodiesel to the diesel fuel decreases the effective efficiency of engine and increases the specific fuel consumption. This is due to the lower heating value of biodiesel compared to diesel fuel. However, the effective engine power was comparable by biodiesel compared with diesel fuel. Emissions of carbon monoxide (CO), oxides of nitrogen (NO_x), sulphur dioxide (SO₂) and smoke opacity were reduced around 15%, 38.5%, 72.7% and 56.8%, respectively, in case of tallow methyl esters (B100) compared to diesel fuel. Besides, the lowest CO, NO_x emissions and the highest exhaust temperature were obtained for B20 among all other fuels. The reductions in exhaust emissions made tallow methyl esters and its blends, especially B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution. Based on this study, animal tallow methyl esters and its blends with petroleum diesel fuel can be used a substitute for diesel in direct injection diesel engines without any engine modification.     

Charcoal from biomass residues of a Cryptomeria plantation and analysis of its carbon fixation benefit in Taiwan

Charcoal production as an age-old industry not only supplies fuel in developing countries, in recent decades, it has also become a means of supplying new multifunctional materials for environmental improvement and agricultural applications in developed countries. These include air dehumidification and deodorization, water purification, and soil improvement due to charcoal's excellent adsorption capacity. Paradoxically, charcoal production might also help curb greenhouse gas emissions. In this study, we made charcoal from discarded branches and tops of wood from a Cryptomeria plantation after thinning using a still-operational earthen kiln. Woody biomass was used as the carbonization fuel. The effect of carbonization on carbon fixation was calculated and its benefits evaluated. The results showed that the recovered fixed carbon reached 33.2%, i.e., one-third of the biomass residual carbon was conserved as charcoal which if left on the forest ground would decompose and turn into carbon dioxide, and based on a net profit of US$1.13 kg⁻¹ for charcoal, an annual net profit of US$14,665 could be realized. Charcoaling thus appears to be a feasible alternative to promote reutilization of woody resides which would not only reduce greenhouse gas emissions, but also provide potential benefits to regional economies in developing countries.     

Improving cost-effectiveness for the furnace in a full-scale refinery plant with reuse of waste tail gas fuel

The waste tail gas fuel emitted from refinery plant in Taiwan e.g. catalytic reforming unit, catalytic cracking unit and residue desulfurization unit, was recovered and reused as a replacement fuel. In this study, it was slowly added to the fuel stream of a heater furnace to replace natural gas for powering a full-scale distillation process. The waste tail gas fuel contained on average 60 mol% of hydrogen. On-site experimental results show that both the flame length and orange-yellowish brightness decrease with increasing proportion of waste gas fuel in the original natural gas fuel. Moreover, the adiabatic flame temperature increases as the content of waste gas fuel is increased in the fuel mixture since waste gas fuel has a higher adiabatic flame temperature than that of natural gas. The complete replacement of natural gas by waste gas fuel for a heater furnace operating at 70% loading (i.e. 3.6 × 10⁷ kcal/h of combustion capacity) will save 5.8 × 10⁶ m³ of natural gas consumption, and 3.5 × 10⁴ tons (or 53.4%) of CO₂ emission annually. Recovering and reusing the waste tail gas fuel as natural gas replacement will achieve tremendous savings of natural gas usage and effectively lower the emission of carbon dioxide.     

Performance improvement of a direct carbon solid oxide fuel cell via strontium-catalyzed carbon gasification

As a new way of power generation, direct carbon solid oxide fuel cells (DC-SOFCs) exhibit great potential in solution of energy crisis and environmental pollution. According to the working principle, the cell operation is a kinetically controlled process, and the reverse Boudouard reaction is the rate-determining step of the whole system. In this study, a Sr-based catalyst is successfully introduced to accelerate carbon gasification and thus enhance cell performance of DC-SOFCs. The electrochemical performance of DC-SOFCs operated on coconut active charcoal with various Sr loading contents (3 wt%–10 wt%), are studied and compared with that of DC-SOFCs with traditional Fe-catalyzed carbon fuel. Experimental results demonstrate that the best output of 316 mW cm⁻² is achieved from the single cell powered with 5 wt% Sr-loaded coconut active charcoal at 850 °C, higher than those of DC-SOFCs fueled by pure and 5 wt% Fe-loaded active charcoal. The superiority of the Sr-based catalyst is also demonstrated by the operation stability of the corresponding DC-SOFC, which displays a relatively long operation time of 22.68 h at 0.25 A cm⁻² with the fuel utilization of 18.3%. The SEM/EDX results indicate that the Sr-based catalyst exhibits good stability without agglomeration during cell operation at high temperature. In addition, the carbon gasification mechanism catalyzed by Sr-based catalyst is also proposed on the basis of these properties. This study indicates that the designed Sr-loaded coconut active charcoal is expected to be an alternative carbon fuel for DC-SOFCs.     

Hydrogen addition to tea seed oil biodiesel: Performance and emission characteristics

Compression ignition engines are the dominant tools of the modern human life especially in the field of transportation. But, the increasing problematic issues such as decreasing reserves and environmental effects of diesel fuels which is the energy source of compression ignition engines forcing researchers to investigate alternative fuels for substitution or decreasing the dependency on fossil fuels. The mostly known alternative fuel is biodiesel fuel and many researchers are investigating the possible raw materials for biodiesel production. Also, hydrogen fuel is an alternative fuel which can be used in compression ignition engines for decreasing fuel consumption and hazardous exhaust emissions by enriching the fuel. In this study, influences of hydrogen enrichment to diesel and diesel tea seed oil biodiesel blends (B10 and B20) were investigated on an unmodified compression ignition engine experimentally. In consequence of the experiments, lower torque and higher brake specific fuel consumption data were measured when the engine was fuelled diesel biodiesel blends (B10 and B20) instead of diesel fuel. Also, diesel biodiesel blends increased CO₂ and NO_x emissions while decreasing the CO emissions. Hydrogen enrichment (5 l/m and 10 l/m) was improved the both torque and brake specific fuel consumption for all test fuels. Furthermore, hydrogen enrichment reduced CO and CO₂ emissions due to absence of carbon atoms in the chemical structure for all test fuels. Increasing flow rate of hydrogen fuel from 5 l/m to 10 l/m further improved performance measures and emitted harmful gases except NO_x. The most significant drawback of the hydrogen enrichment was the increased NO_x emissions.     

Assessment of energy performance and air pollutant emissions in a diesel engine generator fueled with water-containing ethanol–biodiesel–diesel blend of fuels

Biomass based oxygenated fuels have been identified as possible replacement of fossil fuel due to pollutant emission reduction and decrease in over-reliance on fossil fuel energy. In this study, 4 v% water-containing ethanol was mixed with (65–90%) diesel using (5–30%) biodiesel (BD) and 1 v% butanol as stabilizer and co-solvent respectively. The fuels were tested against those of biodiesel–diesel fuel blends to investigate the effect of addition of water-containing ethanol for their energy efficiencies and pollutant emissions in a diesel-fueled engine generator. Experimental results indicated that the fuel blend mix containing 4 v% of water-containing ethanol, 1 v% butanol and 5–30 v% of biodiesel yielded stable blends after 30 days standing. BD1041 blend of fuel, which composed of 10 v% biodiesel, 4 v% of water-containing ethanol and 1 v% butanol demonstrated −0.45 to 1.6% increase in brake-specific fuel consumption (BSFC, mL kW⁻¹ h⁻¹) as compared to conventional diesel. The better engine performance of BD1041 was as a result of complete combustion, and lower reaction temperature based on the water cooling effect, which reduced emissions to 2.8–6.0% for NO_x, 12.6–23.7% particulate matter (PM), 20.4–23.8% total polycyclic aromatic hydrocarbons (PAHs), and 30.8–42.9% total BaPeq between idle mode and 3.2 kW power output of the diesel engine generator. The study indicated that blending diesel with water-containing ethanol could achieve the goal of more green sustainability.     

Performance of a DI diesel engine fuelled by blends of diesel and kiln-produced pyroligneous tar

This paper presents results of experiments undertaken to determine the performance of a direct injection (DI) diesel engine fuelled by blends of kiln-produced pyroligneous tar (PT) and diesel. The PT was sourced from Bulgaria where it was produced from a pine feedstock via a traditional kiln method that involves separation of the aqueous pyroligneous acid fraction. The tar is characterized by high carbon concentration, viscosity and high heating value. Although high, at fuel injection temperatures over 120 °C the tar's viscosity is likely to be lower than diesel. Analysis by GC revealed a number of compounds typically extracted from wood-based tar products. Blends containing 20% and 40% PT with diesel were tested in a 4-cylinder, 4-stoke DI diesel engine. The blends are stable and readily formed. Little difference in engine performance relative to diesel was found for 20% PT blends. PT blends (40%) exhibit significantly higher in-cylinder gas temperature and pressure. Ignition delay for both blends is longer than diesel, as is the fuel burn rate during the premixed stage of the combustion. During the diffusion stage of combustion, the fuel burn rate is lower relative to diesel. The performance of engines fuelled by blends containing 40% or more PT could be improved through optimization of engine systems.     

A study on the performance and emission of a diesel engine fueled with Jatropha biodiesel oil and its blends

Biodiesel either in neat form or as a mixture with diesel fuel is widely investigated to solve the twin problem of depletion of fossil fuels and environmental degradation. The main objective of the present study is to compare performance, emission and combustion characteristics of biodiesel derived from non edible Jatropha oil in a dual fuel diesel engine with base line results of diesel fuel. The performance parameters evaluated were: brake thermal efficiency, brake specific fuel consumption, power output. As a part of combustion study, in-cylinder pressure, rate of pressure rise and heat release rates were evaluated. The emission parameters such as carbon monoxide, carbon dioxide, un-burnt hydrocarbon, oxides of nitrogen and smoke opacity with the different fuels were also measured and compared with base line results. The different properties of Jatropha oil after transestrification were within acceptable limits of standards as set by many countries. The brake thermal efficiency of Jatropha methyl ester and its blends with diesel were lower than diesel and brake specific energy consumption was found to be higher. However, HC, CO and CO₂ and smoke were found to be lower with Jatropha biodiesel fuel. NO_x emissions on Jatropha biodiesel and its blend were higher than Diesel. The results from the experiments suggest that biodiesel derived from non edible oil like Jatropha could be a good substitute to diesel fuel in diesel engine in the near future as far as decentralized energy production is concerned. In view of comparable engine performance and reduction in most of the engine emissions, it can be concluded and biodiesel derived from Jatropha and its blends could be used in a conventional diesel engine without any modification.     

Cofiring multiple opportunity fuels with coal at Bailly Generating Station

Northern Indiana Public Service Company (NIPSCO) has developed a long-term demonstration firing biomass and petroleum coke with coal at its Bailly Generating Station boiler #7, a 160 MW_e (net) cyclone boiler. This demonstration, funded by the US Department of Energy (USDOE) Office of Energy Efficiency and Renewable Energy (EERE) and the USDOE National Energy Technology Laboratory (NETL), has been developed as part of the Electric Power Research Institute (EPRI) biomass cofiring demonstration program. The NIPSCO demonstration program — the triburn program — has involved designing and constructing a fuel preparation and blending facility. It then involved extensive testing of firing clean urban wood waste — biomass — with coal, firing petroleum coke with coal, and firing various blends of urban wood waste and petroleum coke with coal. Results of the extensive testing program have shown that the triburn blends of biomass and petroleum coke with coal have accomplished the following: (1) increased boiler efficiency, (2) reduced fuel costs; and (3) reduced emissions of oxides of nitrogen (NO_x), mercury, and fossil carbon dioxide (CO₂). At the same time, the triburn program has not increased other emissions. This paper summarizes the results of testing at Bailly Generating Station, discusses the impacts of petroleum coke and wood waste, discusses the synergies between these two opportunity fuels, and considers the implications of the demonstration.     

328MW煤粉锅炉掺烧石油焦的应用研究

为解决锅炉燃料热值下降带来的问题,在328 MW煤粉锅炉上进行了石油焦与烟煤的掺烧试验.结果表明:掺入20%石油焦,可使燃料热值明显提高,且不会对着火产生明显影响.掺入位置对锅炉燃尽特性影响很大,仅在下两层磨煤机掺入石油焦时,飞灰含碳量变化很小;当石油焦比例增加或在上层磨煤机也掺入石油焦时,飞灰含碳量明显增加.     

Metal oxide (MgO,CaO, and La2O3) promoted Ni-Ce0.8Zr0.2O2 catalysts for H2 and CO production from two major greenhouse gases

The metal oxide (MgO, CaO, and La₂O₃) promoted Ni-Ce_0.8Zr_0.2O₂ catalysts have been applied for carbon dioxide reforming of methane (CDR) reaction and investigated the coke formation and sintering phenomenon in used catalysts. The Ni-MgO-Ce_0.8Zr_0.2O₂ catalyst exhibits high activity and stability at a very high gas hourly space velocity of 480,000 h⁻¹, resulting from high resistance to coke formation and Ni sintering. This is mainly due to small Ni crystallite size, strong basicity of MgO, and an intimate interaction between Ni and MgO.     

Effects of heat treatment and acid washing on properties and reactivity of charcoal

Due to its highly amorphous carbon structure and abundant minerals content, as received charcoal possesses several undesirable characteristics such as low density and electrical conductivity in addition to its extremely high air and CO₂ reactivities. These disadvantages are the most challenging obstacle for using this material as an alternative for petroleum coke in anode manufacturing processes. In this work, heat treatment under inert conditions was found to be a useful method to improve the molecular structure of charcoal, during this process continuous growth of the more ordered carbon structure at the expense of the amorphous forms was detected using XRD and Raman spectroscopy. Consequently, an improvement in the physical properties and the reactivity of charcoal occurred. In addition, acid washing was employed to eliminate the inorganic minerals of the charcoal. It was found that combination between acid washing and heat treatment produced charcoal having lower reactivity and better physical properties. The burning behavior of the pretreated charcoal samples was found to be comparable to that of calcined petroleum coke. Accordingly, using the pretreated charcoal to substitute up to 10% of coke in the anode recipe did not show a negative effect on the anode's reactivity to both air and CO₂.     

Carbide-based fuel system for undersea vehicles

In underwater applications such as unmanned undersea vehicle (UUV) propulsion, mass and volume constraints often dictate system energy density and specific energy, which are targeted to exceed 300 Wh L⁻¹ and 300 Wh kg⁻¹, respectively, in order to compete with state-of-the-art battery technologies. To address this need, a novel carbide-based fuel system (CFS) intended for use with a solid oxide fuel cell (SOFC) is under development that is capable of achieving these energy metrics as well as sequestering carbon dioxide. The proposed CFS uses calcium carbide and calcium hydride that react with water to generate acetylene and hydrogen as the fuel and calcium hydroxide as a carbon dioxide scrubber. The acetylene is hydrogenated to ethane and then reformed to syngas (carbon monoxide and hydrogen) before being utilized by the SOFC. Carbon dioxide effluent from the SOFC is reacted with the calcium hydroxide to produce a storable solid, calcium carbonate, thus eliminating gas evolution from the UUV. A system configuration is proposed and discussion follows concerning energy storage metrics, operational parameters and preliminary safety analysis.     

Nickel-Zirconia cermet processing by mechanical alloying for solid oxide fuel cell anodes

This paper describes the development of a process based on high energy milling (or mechanical alloying—MA) of metallic Ni and YSZ at 40 vol% Ni composition for the preparation of solid oxide fuel cell anode material. The cermet powder is consolidated using the surface activated sintering (SAS) method. The cermet pellets possess microstructural characteristics that can potentially lead to higher electrocatalytic activity and fuel reforming capability. In addition to the development of a new processing method for this purpose, a further differential of this work is the addition of Cu in partial substitution of Ni as a means to prevent the formation of carbon on its surface and, hence, the anode’s degradation during service. The prepared powder samples are well dispersed and structured at the nanometric level, showing thin lamellar constituents. Suitable sintered pellets can be obtained from the powders with the required porosity and microstructure. The higher the energy delivered by MA the lower the initial sintering temperature. Activation energies are determined by stepwise isothermal dilatometry (SID) for Ni-YSZ and Ni/Cu-YSZ pellets, involving a 2-step sintering process. The Cu additive promotes sintering and leads to a refined microstructure.     

A critical review: Application of methanol as a fuel for internal combustion engines and effects of blending methanol with diesel/biodiesel/ethanol on performance,emission, and combustion characteristics of engines

This article presents a comprehensive overview of methanol as a potential oxygenated fuel for internal combustion engines. Here two approaches have been examined to evaluate the utilization of methanol, namely blending with diesel/biodiesel/methanol and premixing with intake air or fumigation. In conventional compression ignition engines, up to 95% and 25% diesel can be replaced by methanol through fumigation and blending, respectively. Higher latent heat of vaporization of alcohol led to lower peak in-cylinder pressure and NO_x; however, it negatively affects thermal efficiency and hydrocarbon and carbon monoxide emissions. Fumigation of alcohol requires modifications in the existing engine, whereas blending needed surfactants or additives to produce stable alcohol–diesel blends. High injection pressure and late direct injection, methanol–diesel blends have shown lower emissions and proved their potential as a suitable replacement for ethanol–diesel blends from the components durability perspective.     

Bio‐oil,solid and gaseous biofuels from biomass pyrolysis processes—An overview

As the global demand for energy rapidly increases and fossil fuels will be soon exhausted, bio‐energy has become one of the key options for shorter and medium term substitution for fossil fuels and the mitigation of greenhouse gas emissions. Biomass currently supplies 14% of the world's energy needs. Biomass pyrolysis has a long history and substantial future potential—driven by increased interest in renewable energy. This article presents the state‐of‐the‐art of biomass pyrolysis systems, which have been—or are expected to be—commercialized. Performance levels, technological status, market penetration of new technologies and the costs of modern forms of biomass energy are discussed. Advanced methods have been developed in the last two decades for the direct thermal conversion of biomass to liquid fuels, charcoals and various chemicals in higher yields than those obtained by traditional pyrolysis processes. The most important reactor configurations are fluidized beds, rotating cones, vacuum and ablative pyrolysis reactors. Fluidized beds and rotating cones are easier for scaling and possibly more cost effective. Slow pyrolysis is being used for the production of charcoal, which can also be gasified to obtain hydrogen‐rich gas. The short residence time pyrolysis of biomass (flash pyrolysis), at moderate temperatures, is being used to obtain a high yield of liquid products (up to 70% wt), particularly interesting as energetic vectors. Bio‐oil can substitute for fuel oil—or diesel fuel—in many static applications including boilers, furnaces, engines and turbines for electricity generation. While commercial biocrudes can easily substitute for heavy fuel oils, it is necessary to improve the quality in order to consider biocrudes as a replacement for light fuel oils. For transportation fuels, high severity chemical/catalytic processes are needed. An attractive future transportation fuel can be hydrogen, produced by steam reforming of the whole oil, or its carbohydrate‐derived fraction. Pyrolysis gas—containing significant amount of carbon dioxide, along with methane—might be used as a fuel for industrial combustion. Presently, heat applications are most economically competitive, followed by combined heat and power applications; electric applications are generally not competitive. Copyright © 2011 John Wiley & Sons, Ltd.     

Electrolysis of waste water containing aniline to produce polyaniline and hydrogen with low energy consumption

Hydrogen generation from water electrolysis is attempted to be one of the replacement of sources as a clean fuel with high energy density. However, its application is limited by the high overpotential of oxygen evolution reaction (OER). Herein, hydrogen fuel is obtained from waste water by replacing OER with aniline electrochemical polymerization. Compared to the OER, the potential of aniline electro-polymerization greatly decreases 1240 mV at the current density of 30 mA cm⁻² even using carbon paper electrode. Moreover, the Faradaic efficiency of hydrogen production is close to 100%. The as-prepared polyaniline demonstrates good performance as electrochemical capitative materials. This work provides efficient and lower energy consumed access to co-generate hydrogen and polyaniline in a convenient step by starting from the toxic and environmental-unfriendly wastewater.