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Combustion characteristics of a charcoal slurry in a direct injection diesel engine and the impact on the injection system performance
Abstract
The paper presents the research results pertaining to the renewable biomass charcoal–diesel slurries and their use as alternative fuels for combustion in diesel generating plants. The utilization of charcoal slurry fuel aims to reduce diesel oil consumption and would decrease fossil green house emissions into the atmosphere. The paper investigates the formulation, emulsification, sprays, combustion, injection system operation, and subsequent wear with charcoal–diesel slurries. In the research, cedar wood chips were used for the production of charcoal to be emulsified with diesel oil. The slurry’s viscosity of 27cP achieved the target (
... V Soloiu et.al. [34] investigated the combustion properties of a slurry made from charcoal and its effects on the performance of the injection system in a diesel engine with direct injection. In this research, charcoal was produced from cedar wood chips, and then emulsified with diesel oil. ...
... The inclusion of glycerol notably decreased ignition delay time, shortened burnout duration, and elevated droplet burning rate, with a more pronounced effect observed with higher glycerol/water ratios in the slurry fuels. In the Reference [34], the researcher used the slurry of pyrolyzed cedar wood, water, and diesel with different surfactant percentages. At identical maximum combustion pressure and temperature, charcoal slurry exhibited exhaust temperatures that were 40-50 • C higher compared to diesel. ...
... For coal slurries to be considered appropriate for diesel injection systems, it has been recommended that the coal particles should have a size smaller than 88 µm and a mean particle size less than 12-15 µm, while also having no more than 2 % weight ash content [95]. According to the reference [34], a significant challenge when using slurry fuel is the tendency for the fuel injector to become stuck open due to the formation of deposits inside. To address this issue, modifications have been made to the slurry fuel system, including reducing the average particle size of pyrochar from 10.5 µm to 5 µm and adjusting the fuel injector. ...
... Biodiesel fuel blends with additives have different emission characteristics from petroleum diesel counterparts, for example, in the black carbon particulate and NO x concentrations [1][2][3][4]. Elemental carbon (EC) and other inorganic nuclei at an aerodynamic diameter (dp) at~20-30 nm form in incomplete fuel combustion [3,4]. By absorbing airborne organic carbon (OC), post-combustion black carbon size grows rapidly by almost 10 times approaching a μm-size range [5,6]. ...
... Biodiesel fuel blends with additives have different emission characteristics from petroleum diesel counterparts, for example, in the black carbon particulate and NO x concentrations [1][2][3][4]. Elemental carbon (EC) and other inorganic nuclei at an aerodynamic diameter (dp) at~20-30 nm form in incomplete fuel combustion [3,4]. By absorbing airborne organic carbon (OC), post-combustion black carbon size grows rapidly by almost 10 times approaching a μm-size range [5,6]. ...
... The emission and engine performance tradeoffs among binary blends of diesel, biodiesel, ethanol, and n-butanol were assessed [2][3]14,22,29,[32][33][34][35][36][37][38][39]. In some bench-scale experiment studies, n-butanol and ethanol additives affected the engine emission and performance differently because of their unique own physiochemical properties. ...
The use of renewable biodiesel and additives diversifies transportation fuel supply. Combustion tests on neat ultra-low sulfur No.2 diesel (D100) and its blends with biodiesel and the n-butanol additive were conducted to investigate environmental impacts and tradeoffs in engine emission and power output. The testing results show measurable changes in power output and engine emission, particularly in diesel particulate matter (DPM) size distribution and black carbon compositions. The binary diesel-biodiesel blend D80B20 (80% D100 and 20%B100 by volume) offers reduced PM and black carbon emission, but higher NOx in engine exhaust. Comparatively the tertiary diesel-biodiesel-butanol blend B15Bu5 (80% D100, 15% B100, and 5% Bu100 by volume) shows superior environmental tradeoff in the black carbon and NOx emission than D80B20. Both fuel blends suffer a 3.0–5.6% increase in brake-specific fuel consumption. At higher combustion temperature, the butanol-oxygenated diesel fuel produces DPMs of smaller size, higher number concentrations, greater OC fractions, and more amorphous black carbon particles. The peak DPM aerodynamic size dpmax for D80B20 and B15Bu5 blends is 0.20–0.32 μm, smaller than >0.40 μm dpmax for D100 and the 0.30 μm cut-off size of regular DPM filters. For an internal combustion engine capable of accommodating biodiesel and water fraction in the fuel mixture, the B15Bu5 blend offers a viable fuel alternative according to the comparative testing results. The use of biodiesel and butanol additive in petroleum diesel can decrease the DPM emission, while the undesired NOx formation in tradeoff can be managed through optimizing the tertiary composition of petroleum diesel, biodiesel, and fuel additives.
... Biomass is a term used for all kinds of wood, agricultural, and forest residues that are renewable, clean, and CO2 neutral with loads of resources in the nature (Soloiu et al., 2011). Currently around 10% of the global energy production refers to Bioenergy (Council, 2015) However, biomass will have a potential to become a more important source of energy in the future. ...
... These standards refer to viscosity value, heating value, stability and good atomization characteristics. According to the previous studies done by the other researchers, the most important factors affecting the bio-coal slurry features are the raw material of the bio-coal, particle size distribution, liquid carrier, and temperature (Long, 2014, Soloiu et al., 2011. ...
... Recently, similarities of bio-coal properties to that of coal had encouraged researchers to use bio-coal instead of coal in slurry fuels. For example, (Soloiu et al., 2011, Long, 2014, N'kpomin et al., 1995, Awang and May, 2009, Esnouf, 1991 investigated the bio-coal slurry using different kind of liquids including water, vegetable oil ,oil, and a mixture of them. However, there is still a huge gap between properties of the coal slurry and bio-coal slurry, for instance, coal comprises more slurryability than bio-coal therefore coal-water slurry shows more heating value than bio-coal-water slurry, but efforts are being done to decrease these gaps. ...
... The image shows mostly circular crystal filaments with few semicircular crystal filaments. The image also reveals that the CB powder has an average particle size of 40 µ, which is favourable for solid particle combustion (Soloiu et al. 2011). ...
... It also revealed that in the temperature range between 450 o C and 700 o C, about 80% of the CB oxidized. The figure also showed that at 450 o C, the oxidation reaction was intensified, with a higher exothermic reaction from the CB (Soloiu et al. 2011). ...
Activated charcoal is known as powerful adsorbent and has been associated for the removal of heavy metal and poisonous substance from the environment predominantly water, gases and human body. It is helpful in treating waste water by removing organic and inorganic components. They are extensively used to control pollution by removing impurities or disagreeable components from liquids and gases. It is also used at various places to improve the quality of air. This chapter focuses on the roles of the activated charcoal in controlling environmental pollution both in water and gases. Activated charcoal is also known for treating human body parts such as kidney. Person suffering from renal failure can enhance the renal dialysis by the effective use of activated charcoal. Activated charcoal has numerous products and their applications that are widely known in biomedical and medicine fields are discussed in the chapter. This chapter also focuses on different applications and future prospects of the same.
... In addition, the combustion duration of slurry fuels increases considerably compared to diesel fuels. Recently, a comprehensive study on combustion characteristics of a biochar slurry in a direct injection diesel engine and the impact on the injection system performance has been reported [13]. The study has proven that a biochar slurry fuel can produce adequate sprays and burns with very good results in a diesel engine. ...
... However, there are several pilot research activities on direct coal slurry use in diesel engines. Electrical efficiency reported by Soloiu et al. [13] for hydrochar slurries in diesel engines is in the range of 30-35 %. Typical coal-based power plants have efficiency in the range of 36 to 38 %. ...
This paper deals with process simulation and techno-economic assessment on a bioenergy system for sustainable electricity production from low-grade biomass resources such as forest and agricultural residues, which is suitable for rural areas in developing regions susceptible to intermittent electricity supply. The core of the system is hydrothermal carbonization of wet biomass for production of hydrochar, followed by wet milling and direct combustion of the obtained hydrochar slurry fuels for heat and power generation. In order to improve the economy and make the process a closed-loop system, the paper also identifies a bio-refining strategy focusing on production of high-grade activated carbons for energy storage using supercapacitor. Aspen Plus software package is used as simulation and optimization tool. The result shows that the proposed system is highly feasible both technically and economically. The cost of electricity varies from 0.2 to 0.4 $/kWh in the efficiency range of (40 % to 20 %), which depends on the hydrothermal carbonization operating conditions.
... Slurry fuel from renewable biomass can be classified as a better energy product than coal. Biochar slurry fuel creates a homogeneous mixture by mixing finely ground biochar with water and other potential additives (Soloiu et al., 2011). The production process includes numerous steps, including the pyrolysis of biomass to produce biochar, the reduction of particle size through grinding, and blending biochar with water to make the slurry. ...
Biomass derived from agricultural waste in Indonesia is abundant and has potential as a source of renewable energy feedstock. However, analysis is needed to determine the appropriate technology to convert potential biomass into consumable energy forms. This review summarises various data on Indonesia’s potential biomass that can be used as a renewable energy feedstock. Biomass and biochar characteristics are systematically discussed, including proximate and ultimate analysis. We then summarise various biochar production technologies based on the biomass used and their yields. The characteristics of biochar produced in both proximate and ultimate analysis and the conversion of biochar into slurry fuel as one of the consumable forms of renewable energy were discussed. Slurry fuel is a potential use of biochar as a liquid fuel. The challenges of developing potential biomass-based bio-slurry production in Indonesia and the future work that needs to be done are presented.
... In the pyrolysis process, operating temperature conditions have a significant impact on the final product composition [180,181]. Common fast pyrolysis products include bio-oil, biochar, and syngas. The bio-oil is strongly influenced by the operating temperatures and biomass types, while its physicochemical properties and content, such as percentage of hydrocarbon, acidity, and viscosity, depend on the catalysts used and operating temperature of the process [182,183]. ...
The increasing energy demand and diminishing fossil fuel sources have called for the exploration of new energy sources. To satisfy growing global energy demand and accomplish sustainable energy development goals, biomass plays an essential role in present and future energy. Pyrolysis holds considerable potential approaches among biomass conversion technologies. This study presents a critical review of the effect of the key pyrolysis parameters from lignocellulosic biomass to product distribution. The lignocellulosic biomass composition and pyrolysis conversion behavior of every single component was discussed in detail. On top of that, CO 2-based benefits, economic assessment, and technical orientation for biofuel production from biomass are included. The carbon and hydrogen content of biomass is critical for producing high-quality bio-oil. When compared to other energy crops and agricultural residues, pyrolysis of clean wood and polar demonstrated the best bio-oil production. The increased cellulose and hemicellulose content aiding in the synthesis of bio-oil, but the high concentration of lignin results in more biochar. The article delves into product upgrading via several routes such as physical, chemical, and catalytic. From the review, considering factors such as pyrolysis technologies, energy demand, and bio-oil yields, greenhouse potential benefits needs to be evaluated, and this needs to be done on an individual basis. In terms of production cost, the current cost of biomass feedstock can range between 97/ton, which is approximately 30− 54% of the liquid fuel production cost. A wide range of studies covering different aspects of biomass pyrolysis technology, from reactor configuration and the heating source to single and poly-step pyrolysis processes, have been carried out in the search for solutions in optimizing the current technologies. Thus, expanding and improving awareness of the lignocellulosic biomass in the pyrolysis technology would play an important role in producing sustainable and renewable carbon-neutral fuels.
... In 2004, Wilson [15] from TIAX LLC company ran a Colt Pielstick PC2.6 two cylinder engine with a Kentucky coal-based CWS for one hour with no major problems. As an alternative to using coal slurry, Soloiu et al. [16] studied the use of a 10 µm charcoal slurry (25% by weight) on a Yanmar Nf-19 engine and found engine performance very similar to that with diesel, and net heat release even higher than in the case of pure diesel operation. ...
Recently, the production of sustainable biofuels from algal biomass has gained significant attention and been investigated as a potential replacement of fossil fuel. However, existing downstream processes for producing biodiesel from algae cells are complex, highly energy-intensive, and have high economic and environmental cost. Therefore, this work introduces an alternative and novel method of utilizing the energy content of microalgae that precludes lipid extraction by aspirating wet algal biomass suspensions directly into the intake air of an internal combustion engine.
For all engine experiments, powdered algae cells were prepared as slurries at different biomass concentrations. The impacts of (i) varying the biomass concentration with constant suspension injection flowrate into the engine intake and (ii) varying suspension injection flowrate with constant biomass concentration were investigated.
A correlation between engine work produced during combustion and algal biomass aspiration was found. At constant flowrate and greater than 5% biomass concentrations, an increase of energy release during combustion from the aspirated algae could be observed. However, the aspiration of low concentration biomass suspension produced a negative impact on engine performance relative to water-only aspiration. The engine exhaust gas of nitrogen oxides (NOx) was reduced for all algae suspension tests relative to diesel-only combustion. However, the carbon monoxide (CO) emission level was much higher relative to diesel-only tests at high biomass concentrations and injection flowrate.
These findings demonstrate the possibility of utilising the energy content of algal biomass in combustion without lipid extraction, with added benefits of reducing NOx emissions.
... Nevertheless, these aspects should be deeply investigated in order to develop these new automotive fuel systems [135]. Indeed, more target efforts have to be made for reducing the particle sizes, the amount of ash production, and hardening the injectors [136]. A major drawback in the implementation of this kind of fuels for power station applications, is the necessity to produce slurries highly charged in char (to enhance the energy content) with a viscosity compatible to the pumping procedures and atomization of the fuel. ...
Biomass-derived chars present energy density values close to those of fossil fuels and therefore they are good candidates in electricity or heat production plants with only minor drawbacks compared to fossil fuels. Even if co-firing seems the most attractive solution for near-term applications, processes based on combustion and gasification (which are competing in dependence of the need of heat or electricity) are receiving renewed attention. Thanks to their high carbon content, and their high specific surface area and developed porous structure, biomass-derived chars can be treated and converted into activated carbons and applied in many different field (as energy storage materials for gaseous fuels, mainly hydrogen and methane, or as electrodes). They can constitute the raw materials for preparing synthetic graphite, which can be used in some types of batteries and fuel cells, and in carbon electrodes for electrochemical capacitors. The performances in terms of capacitance, electrical conductivity, potential, charge and discharge rates, power density, etc. have been reported to be very close to those of commercial devices. The recent progress in the activation protocols brought to higher fuel gas storage capacities, especially in cryogenic conditions and under high pressure, and opened the possibility to apply these materials in new application fields. In catalysis, advances in the use of biomass-derived chars and active carbons have been made thanks to the improvement of the modification techniques. The optimization of the engineering methodologies allows to lower the cost of the activation processes of biomass-derived chars and to tune the char properties to adapt them to the final application. The present paper aims to give a comprehensive survey of already-well-established or future potential energy applications of biomass-derived chars. A critical comparison of their use in different processes is reported and their modification by various catalytic, physical and chemical routes is detailed.
... Our results also showed GO significantly improved the droplet combustion of palm biodiesel [12]. Besides, a comprehensive investigation by Soloiu et al. [13] on the combustion characteristics of carbon slurries in a direct injection diesel engine and the impact on the injection system performance has shown that the new carbon-diesel slurry can produce adequate sprays and burn with very good results in a diesel engine. ...
Graphene and carbon nanotubes have drawn interest across many disciplines due to their remarkable properties. We investigated the effects of graphite oxide (GO), single-walled carbon nanotubes (SWCNTs), and cerium oxide (CeO2) nanoparticles on the combustion, performance, and emission characteristics of a four-stroke single cylinder light-duty diesel engine under various engine loads. Shortened ignition-delay (ID) by up to 10.3%, advanced combustion phasing (up to 18.5%), shortened combustion duration (up to 14.6%), improved brake specific fuel consumption (BSFC) by up to 15.2%, reduced CO emission (up to 23.4%), and lowered UHCs emissions (up to 24.1%) were achieved with the addition of SWCNTs nanoparticle at 25 ppm dosing ratio. SWCNTs and GO additives could be effective approach for lowering emissions in diesel engine applications.
... Soloiu et al. [20] investigated the charcoal slurry as renewable fuel in direct injection compression ignition engine and its influence on injection system characteristics. It was found that the combustion peak pressure for charcoal slurry comparable to conventional diesel with longer ignition delay period. ...
The present work examines the prospect of using 100% Calophyllum inophyllum methyl ester as a promising alternative fuel for future generation. In this research work, a strategy is developed to reduce NOX emissions of Calophyllum inophyllum biodiesel fuelled diesel engine by varying the injection timing between 21°, 23° and 25° bTDC and by admitting exhaust gas recirculation at the rate of 10%, 20% and 30%. The experiments are conducted in a four stroke diesel engine using 100% Calophyllum inophyllum biodiesel and the engine characteristics are compared with neat diesel engine. Certain important parameters like brake specific energy consumption, brake thermal efficiency, heat release rate, in-cylinder pressure, exhaust emissions including NOX and smoke density are evaluated for various injection timing and EGR rates. Retardation of injection timing to 21° bTDC reduces the NOX emissions very marginally with significant loss in engine performance. It is found that 10% exhaust gas recirculation rate could reduce the NOX emissions more effectively which would meet the proposed Euro V standards. Thus it is observed that exhaust gas recirculation is an effective method to control emissions of 100% Calophyllum inophyllum biodiesel without much compromise in engine efficiency when compared to the influence of injection timing.
... In addition, the combustion duration of slurry fuels increases considerably compared to diesel fuels. Recently, a comprehensive study on combustion characteristics of a biochar diesel slurry in a direct injection diesel engine and the impact on the injection system performance has been reported [46]. The study has proven that a biochar diesel slurry fuel can produce adequate sprays and burns with very good results in a diesel engine. ...
This paper describes and analyzes a conceptual design of a bioenergy system for sustainable electricity production from low-grade biomass resources such as forest and agricultural residues, which is suitable for rural areas in developing regions susceptible to intermittent electricity supply. In order to make it a closed-loop system, the paper also identifies a bio-refining strategy focusing on production of high-grade activated carbons for energy storage using supercapacitor.
... In this regard, biochar is much more reactive than coal, due to its higher surface area and the presence of surface functional groups [24], and has less ash and sulphur contents in comparison to coal [10], rendering it more suitable for applications as slurry fuels in diesel engines with expected good engine performance. Recently, burning biochar/ water/diesel slurry fuels in diesel engines were attempted [25,26] and the results, although very limited, have indicated that the slurry fuels could produce adequate sprays and burn effectively under certain conditions. These tests also showed that the biochar slurry fuels incurred significantly reduced engine abrasion rates when compared to coal based slurry fuels. ...
The ignition and combustion behaviour of single droplets of slurry fuels made from a coconut shell biochar and a pine sawdust biochar was experimentally investigated. The two types of biochar water slurry fuels were prepared with water content varying from 50 to 70 wt% and the median size (D50) of the biochar particles being approximately 10 μm. Single droplets of the slurry fuels with diameters ranging from 0.5 mm to 1.5 mm were suspended on a silicon carbide fibre and burned in air at 1023 K in an electrically heated tube furnace. The ignition and combustion processes of the droplets of the slurry fuels were recorded using a colour CCD camera at 200 fps. The ignition delay time, burnout time and burning rate based on the d² law were determined. It was found that the ignition delay time slightly increased first and then decreased as the water content increased from 50 wt% to 70 wt% for the coconut shell biochar slurry fuels and from 60 wt% to 70 wt% for the pine sawdust biochar slurry fuels, indicating that the effect of water content on the ignition delay time was a trade-off between the water evaporation time and the heating time of residual solid after water evaporation. The combustion of residual solid after ignition followed a shrinking sphere model and was controlled by external oxygen diffusion to the outer surface of the residual solid and a shallow region below the outer surface. The burning rate of the residual solid calculated based on the d² law ranged from 0.07 to 0.15 mm² s⁻¹, which was also independent of the initial droplet size. A slurry fuel with a higher water content showed a slightly greater burning rate as the voids of inter-particles after water evaporation became larger for slurry fuels with higher water contents.
... The high specific consumption along with the need to use costly clean fuels [20] so as to comply with ISO-F DMA regulations [29][30][31], make the turbines a less attractive option to be used on ships. However, the GT enables the recovery of waste heat for the implementation of a combined cycle, thereby increasing plant efficiency to 40%. ...
Vessel ozone depleting emission regulations are regulated in Annex VI of the MARPOL Convention, wherein the maximum levels of NOx, SOx and suspended particles are established. These increasingly strict regulations, together with the increase in natural gas consumption and its price, have conditioned propulsion systems implemented on board vessels. This article reviews the different propulsion systems used on board vessels for the transport of Liquefied Natural Gas (LNG). The study describes the main characteristics of the propulsion systems, and the advantages and drawbacks that come along with these, from its very beginnings up to the systems installed to date. The described propulsion systems include both gas and steam turbines, combined cycles, 2 and 4 stroke internal combustion engines, as well as reliquefaction plants, while encompassing mechanical, electric and Dual Fuel (DF) technology systems. The propulsion systems implemented have undergone continual alteration in order to adjust to market needs, which were always governed by both efficiency and the possibility of consuming boil-off gas (BOG), always in compliance with the strict antipollution regulations in force. The current direction of LNG vessel propulsion systems is the installation of 2-stroke DF low pressure engines due to their high efficiency and their possibility of installing a BOG reliquefaction plant. Another great advantage of this propulsion system is its compliance with the IMO TIER III emission regulations, without the need to install any supplementary gas treatment system.
... This is more suitable in remote and rural areas where power is currently produced from diesel generators and where biomass is also an abundant primary energy resource. Burning biochar-diesel and biochar-diesel-water slurry fuels in diesel engines has recently been trialled and the results indicate that the biochar slurry fuels could produce adequate sprays, burn effectively and incur low engine abrasion rate in medium and low speed engines with some modifications to the fuel injection system [5][6][7][8]. The main challenge with regards to the use of biochar slurry fuels is the preparation of slurry fuels with desirable rheological properties while maintaining high heating value and good ignition and combustion characteristics. ...
The rheological behaviour and stability characteristics of biochar-glycerol-water slurry fuels were experimentally investigated, emphasising the effect of glycerol addition. A pine sawdust biochar with a size fraction of < 32 μm and a median particle size (D50) of approximately 12 μm was used. A biochar-glycerol-water slurry fuel was prepared by dispersing biochar particles in a premixed glycerol/water solution as the suspending medium with glycerol content varying from 0 to 100 wt%. 2 wt% lignosulfonic acid sodium salt (LASS) (on the basis of dry weight of biochar) was added to the suspending medium as a dispersant. The effect of glycerol content on the rheological properties and stability characteristics of the slurry fuels were studied. The yield stress was measured with a Brookfield vane viscometer and the dependence of apparent viscosity and shear stress on the shear rate was characterised using a Haake VT550 cone and plate viscometer. The stability characteristics of the slurry fuels were characterised by using a “drop rod” method. As glycerol content increased, the maximum biochar loading decreased from 50 to 10 wt% while the calorific values of the slurry fuels first increased and then decreased, reaching a maximum of 21 MJ kg− 1 at 90 wt% glycerol content. For a given biochar loading, increasing glycerol content increased the viscosity of the suspending medium and therefore the viscosity of the slurry fuels, displaying higher yield stress, more apparent shear-thinning behaviour and higher stability due to the enhanced flocculation of biochar particles.
... Zhang et al. discussed the recent developments and potential applications of thermochemical processes for biomass conversion to bioenergy [4]. Co-combustion of renewable biomass charcoal and diesel slurries as alternative fuels in diesel generating plants was investigated by Soloiu et al. [5]. Torrefaction and carbonization as pre-treatment steps for the production of solid fuels from lignocellulosic biomass was reported by Kambo and Dutta [6]. ...
... During this process the spherical particles start burning the outer layers, which process releases a significant amount of heat in a quick manner, which further results in the quick dissipation of heat before the next layer starts degenerating. Hence such kinds of peaks are often found in samples with several layers of carbon or in the presence of a metallic catalyst [18,19]. ...
Amorphous agglomerates of carbon nanospheres (CNS) with a diameter range of 10-50 nm were synthesized using the solution combustion method. High-resolution transmission electron microscopy (HRTEM) revealed a densely packed high surface area of SP2-hybridized carbon; however, there were no crystalline structural components, as can be seen from the scanning electron microscopy, HRTEM, X-ray diffraction, Raman spectroscopy, and thermal gravimetric analyses. Electrochemical and thermo catalytic decomposition study results show that the material can be used as a potential electrode candidate for the fabrication of energy storage devices and also for the production of free hydrogen if such devices are used in a fluidized bed reactor loaded with the as-prepared CNS as the catalyst bed.
... Coal-water slurry (CWS) is an attractive fuel in engineering because of the nature of being easily pumpable and transportable in pipeline. It is customarily applied to boiler combustion and entrain flow gasification [1], and potentially to turbine or engine fueling as a substitute of oil [2] and even to electrolysis for hydrogen production [3]. It is always desired that CWS holds more coal under the guaranteed fluid properties. ...
... In 2011, under the funding of the Japanese Ministry of Energy, Soloiu et al. [48], working with a Yanmar NF-19 engine led a very comprehensive experimental study on a 10 mm char obtained from cedar wood chips, slurried at 25% (by weight) in diesel oil. Their conclusions indicate slurry performances very similar to pure diesel, with very close ignition delays, and higher net heat releases for charcoal slurry in comparison to pure diesel. ...
The direct use of dry biomass dust as a fuel in reciprocating engines could be of great interest because of the large availability of plant matter and the versatility of Internal Combustion Engines (ICE). Coal dust was used in the past and mostly in slurries because of large production during industrial era in Europe but led to many problems caused by fuel handling and wear in ICE. In comparison, biomass has a CO 2 neutral impact, and is almost ash and sulphur free. Biomass pulverization technologies are now mature and the raw material can be reduced to micronic size or even smaller. Among the various new and renewable fuels under research and development, solid raw biomass is certainly the most promising advanced biofuel. It requires no or little thermochemical or biological processing or upgrading and potentially does not generate waste, detrimental to the environment. After a general overview of the past attempts to run reciprocating engines with coal dust, this paper will assess the so far unconsidered use of dry biomass dust as a fuel in engines instead of abrasive, less volatile and more polluting coal dust.
High-energy-density fuels are promising fuels for advanced aero engines, especially rotary engines, in which atomization characteristics play a crucial role in fuel practical application. This work experimentally investigated the basic spray characteristics mainly including spray angle, droplet concentration, velocity, and size distribution of two liquid fuels JP-10, HEF-1 and one slurry fuel HEF-2 by PDPA technique using a fuel slinger under 10000 to 25000 rpm. Effects of fuel physical properties (fuel type, density, viscosity, surface tension, etc) and control parameters (rotational speed and fuel flowrate) on atomization characteristics were discussed. The results showed that the droplet number was parabolic distribution for each fuel and significantly increased with the elevated rotational speeds. Slurry fuel had the largest droplet number near the spray center due to the fragmentation effect of nano-Al particles. For liquid fuels, viscosity determined the droplet breakup below 10000 rpm. Spray angle and droplet velocity negatively related to fuel viscosity. Besides, elevated rotational speeds promoted average droplet velocities, while lowered spray angles. Overall, Sauter mean diameter (SMD) of each fuel greatly depended on fuel viscosity was arch bridge-type distribution. Slurry fuel possessed a smoother distribution with much larger SMD (55∼65 μm) than liquid fuels (20∼45 μm). Furthermore, the average SMD (ASMD) of JP-10 and HEF-1 gradually decreased from 58 μm to 40 μm, and 44 μm to 35 μm, respectively as rotational speeds increased. Additionally, they increased by less than 20% when flowrates increased from 0.15 Lpm to 1.20 Lpm. Nevertheless, slurry fuel HEF-2 had an ASMD around 65 μm which remained almost unchanged with varying rotational speeds and flowrates.
Diesel engine generators are one of the major methods for off-grid and on-demand electricity generation, particularly in the remote areas of some developing countries. However, access to fossil diesel is often limited by supply or price. In many regions, biomass is an abundant source of energy, but many types are not suitable for producing traditional liquid biofuels such as biodiesel. This paper explores the use of so called ‘slurry fuels’ produced by the blending of micron sized particles of carbonaceous material in diesel and assesses whether these ‘slurry fuels’ can be used in a standard diesel engine generator with minimal modification.
Two types of micronized carbon chars were added to diesel, produced by either pyrolysis or hydrothermal carbonization of biomass. The results indicated that at high engine power, the micronized carbon slurry fuels can be run at a similar efficiency as pure diesel. The major issues identified included high engine wear and the blockage of the fuel injector. Hydrothermal carbonization was found to be the best thermal conversion route for producing micronized carbon in terms of emissions when blended with diesel.
Production of energy from lignocellulosic biomass using internal combustion engines (ICE) is desirable, provided that costs can be reduced. The recalcitrance of lignocellulosic biomass requires additional treatments for second-generation biofuel conversion processes, falling short of sustainability goals and profit margins. Rather than transforming solid biomass to liquid or gaseous fuels through multistep processes, this paper explores the direct use of biomass powder below 200µm in an engine. Reducing biofuel production to a single milling process offers the chance to downscale biofuel production for implementation at the local level, through standalone or hybrid installations with other renewable energies. In scenarios using intermittent energies such as solar or wind, production of biomass powder can be operated during low demand periods to store surplus energy which can be later used for generating power on demand. To test the feasibility of this concept, four biomasses (rice husk, chestnut wood, pine bark, and wheat straw) were micronised to an average particle size of 20μm and fuelled in an instrumented ICE. Our results confirm that an ICE can start and run with various biomass types at a wide range of operating regimes without any assistance. During these tests, efficiencies up to 17.5 % were observed with powdered rice husk, using an intake temperature of 40°C. Emissions (CO, NOx, and SO2) were found to be within acceptable operating limits of available aftertreatment technologies. This first assessment of the compared combustion behaviour of different biomass powders in ICE highlights the fact that the challenges associated with this alternative biofuel demand a cross-disciplinary approach from research domains such as dust explosion prevention, biomass combustion and engine technology.
Direct Injection of methyl oleate and PFI of n-butanol were used to conduct Reactivity Controlled Compression Ignition (RCCI) and minimize exhaust emissions in reference to conventional diesel combustion. Methyl oleate was investigated for validation of a single fatty acid methyl ester as a surrogate for biodiesel in engine operation. An experimental common rail engine was operated in RCCI and conventional diesel combustion modes under constant boost and similar combustion phasing. The RCCI strategy used two pulses of direct injections with a fixed first injection at 60° before top dead center and a varied second injection for smooth combustion. Ringing intensity was reduced by 70% for methyl oleate RCCI compared to diesel conventional diesel combustion. The molecular oxygen from methyl oleate allowed a reduction in soot by 75% and 25% compared to diesel in RCCI and conventional diesel combustion operation, respectively. Compared to conventional diesel combustion, NOx and soot decreased for RCCI by several orders of magnitude with both emissions approaching near zero levels at low load. The fuels produced a stable RCCI operation where mechanical efficiency was sustained within 2% for same-load points and the coefficient of variation of indicated mean effective pressure was limited to 2.5%.
LTC was researched by introducing an 80% mass fraction of n-butanol in reactivity controlled compression ignition (RCCI) mode. A 60% mass fraction of n-butanol was port fuel injected (PFI) and the additional 20% was directly injected through a blend of n-butanol (Bu) with Fischer-Tropsch gas to liquid synthetic paraffinic kerosene (GTL) or ULSD as reference. The blended fuels GTL20-Bu80 and ULSD20-Bu80 have reduced cetane for improved combustion phasing control compared to the reference RCCI mode with direct injection of neat ULSD and n-Butanol PFI (ULSD40-Bu60). RCCI strategies delayed ignition and increased peak heat release rates due to prolonged mixing time and reactivity stratification, inducing faster flame speeds. In RCCI mode, the ringing intensity (RI) increased up to 85% higher than in CDC. NOx and soot were reduced up to 90% with ULSD40-Bu60 compared to CDC. The butanol blends decreased CO by 25% compared to ULSD RCCI. CO levels overlayed each other for GTL20-Bu80 and ULSD20-Bu80 across loads, suggesting that the butanol was the influencing factor. ULSD and ULSD20-Bu80 RCCI increased mechanical efficiencies compared to CDC by 3–4% across loads. ULSD20-Bu80 had the lowest cetane and displayed the greatest improvement in the overall emissions and efficiencies in RCCI compared to CDC.
Direct injection (DI) of cotton seed biodiesel (CS100) with port fuel injection (PFI) of n-butanol was used for producing Premixed Controlled Compression Ignition (PCCI) to achieve low-temperature combustion (LTC) and obtain lower gaseous emissions in comparison to ULSD#2 (ultra-low sulfur diesel). PFI engine operation was compared to the combustion of binary mixtures of the same fuels reflecting the same weight ratio of high reactivity (CS100) and low reactivity (n-butanol) fuels. The supercharged engine was operated at constant speed and load with 20% exhaust gas recirculation (EGR). When compared to ULSD#2 reference, the ignition delay of 50% n-butanol and 50% CS100 binary mixture increased by 12% while the 50% n-butanol PFI with 50% CS100 DI led to a 17% decrease in ignition delay. Emissions of soot and nitrogen oxides were simultaneously improved using the PCCI strategy, reducing by 84% and 17%, respectively, given lower peak in-cylinder temperatures and increased oxygenation of the mixture. Carbon monoxide (CO) and unburned hydrocarbons (UHC) increased by several orders of magnitude as a downside of dual fuel injection; ringing intensity, however, improved, decreasing by 30% when using 50% n-butanol PFI in comparison to the ULSD#2 baseline given a smoother pressure gradients. Energy specific fuel consumption for CS50Bu50 (50% ULSD-50% n-butanol blend) increased by 4.5% compared to ULSD#2. The mechanical efficiencies and the coefficient of variation (COV) of IMEP were maintained at 70% and 2.5% respectively, during PCCI, indicating stable operation with renewable fuels.
This work reports on a preliminary study aimed at developing an industrial liquid fuel derived from charcoal and vegetable oil. Its relevance relies on the high energy potential of charcoal, its renewable nature, storage and transportation capacity in liquid form, as well as on the economic and environmental advantages derived thereof. The ability of a commercially available charcoal to be dispersed in three different organic solvents was assessed through the rheological characterisation of the resulting charcoal oil slurries (ChOS). The charcoal was ground in a conventional ball mill and dispersed with the aid of three different surfactants. The effects of the most relevant factors influencing the rheological properties of the suspensions were evaluated, including: (i) the solvent producing the lowest fuel viscosity (η) at a given charcoal content; (ii) the most efficient surfactant (and its amount) minimising the fuel viscosity (η) at a given solids fraction; and (iii) the charcoal content, which should be as high as possible. High-stability ChOS containing 62 wt% solids and 0.4 wt% surfactant, and exhibiting adequate flow properties and high calorific values, were successfully obtained.
Developing an industrial liquid fuel based on charcoal and water was the target of the present work. The relevance of this study is justified by the high energy potential of charcoal, its renewable nature, the easiness of storage and transportation in the liquid form, and by all the associated economic and environmental advantages derived thereof.
The ability of a commercially available charcoal to be dispersed in water was evaluated by analysing the rheological behaviour of the resulting charcoal water slurries (ChWS). The charcoal was ground in a conventional ball mill and dispersed in water with the aid of different surfactants. The effects of the most relevant factors influencing the rheological properties of the suspensions were evaluated, including: (i) type of surfactant and its added amount on the fuel viscosity (η) at a given solids fraction; (ii) the charcoal content, which should be as high as possible. The results enabled selecting the most efficient surfactant and its optimal amount required for minimising the fuel viscosity (η) and enhancing the stability of the suspensions. Stable ChWS containing 60 wt.% solids and 1 wt.% surfactant and exhibiting adequate flow properties were successfully obtained.
This study examines the temperature change of droplets of coal-water slurry containing petrochemicals (CWSP). The slurry consists of coal and oil processing waste. The temperature of oxidant in a modelled combustion chamber is varied between 600–1200 K. The initial size (radius) of CWSP droplets varied in the range of 0.5–3 mm. The study identifies typical temperature trends at the center and on the surface of the CWSP droplet. The temperature trends represent the following stages: (i) heating of fuel, (ii) evaporation of water and a liquid combustible component, (iii) thermal decomposition of coal and yield of volatiles, (iv) gas phase ignition of volatiles together with vapor of the combustible liquid, and (v) heterogeneous ignition of carbon and its burnout. Moreover, these trends indicate the maximum combustion temperatures of CWSP that reflect corresponding heat release. The study specifies the parameters which influence the maximum combustion temperature: fuel component composition, properties of components, droplet size, and the oxidant temperature. Finally, the study defines the minimum ignition temperatures and delay times of sustainable combustion initiation that characterize the ignition inertia. The knowledge of influence of these factors will allow one to predict the optimal conditions for the combustion of the CWSP.
The study results of ignition of organic coal-water fuel (OCWF) compositions were considered. The main problems associated with investigation of these processes were identified. Historical perspectives of the development of coal-water composite fuel technologies in Russia and worldwide are presented. The advantages of the OCWF use as a power-plant fuel in comparison with the common coal-water fuels (CWF) were emphasized. The factors (component ratio, grinding degree of solid (coal) component, limiting temperature of oxidizer, properties of liquid and solid components, procedure and time of suspension preparation, etc.) affecting inertia and stability of the ignition processes of suspensions based on the products of coaland oil processing (coals of various types and metamorphism degree, filter cakes, waste motor, transformer, and turbine oils, water-oil emulsions, fuel-oil, etc.) were analyzed. The promising directions for the development of modern notions on the OCWF ignition processes were determined. The main reasons limiting active application of the OCWF in power generation were identified. Characteristics of ignition and combustion of coal-water and organic coal-water slurry fuels were compared. The effect of water in the composite coal fuels on the energy characteristics of their ignition and combustion, as well as ecological features of these processes, were elucidated. The current problems associated with pulverization of composite coal fuels in power plants, as well as the effect of characteristics of the pulverization process on the combustion parameters of fuel, were considered. The problems hindering the development of models of ignition and combustion of OCWF were analyzed. It was established that the main one was the lack of reliable experimental data on the processes of heating, evaporation, ignition, and combustion of OCWF droplets. It was concluded that the use of high-speed video recording systems and low-inertia sensors of temperature and gas concentration could help in providing the lacking experimental information.
This work aims at the study of the slurryability of a Chinese lignite and various chars derived from coal pyrolysis and hydrothermal treatment. Coal pyrolysis was conducted in an air-isolated atmosphere with a changing temperature from 300 °C to 700 °C. Hydrothermal treatment of coal was carried out in autoclave at temperatures from 150 °C to 300 °C with autogenous pressure from 0.8 MPa to 9.2 MPa. The results showed that the raw lignite had the poor slurryability, and the chars exhibited an improved slurryability depending on the pretreatment methods. The char obtained by pyrolysis at 400 °C was prepared to a char-water slurry with the char loading of 59 wt%, the apparent viscosity of 1208 mPa s, and the good stability. The char obtained from the hydrothermal treatment also showed the improved slurryability as compared to the YX raw lignite. The apparent viscosity was found to be correlated to the elimination of the hydrophilic carboxyl group by pretreatment for the char-water slurries. Rheological analysis showed that both the lignite-water slurries and the char-water slurries well fitted to the power low model, and the char-water slurries had a larger value of the rheological exponent (n) and a more gradual decrease in the n value with the solid concentration increasing than the lignite-water slurries.
The aim of the present work is to experimentally investigate the combined effects of compression ratio, nozzle opening pressure and injection timing on the performance and emissions of a CI (compression ignition) engine operated with an emulsion fuel obtained from CB (carbon black). The emulsion contained CB 10%, 2% water, 85% diesel and 3% surfactant was denoted as CBWD10. Tests were carried out with the CBWD10 emulsion in a single-cylinder, four -stroke, air cooled, DI (direct injection) diesel engine developing power of 4.4 kW at a constant speed of 1500 rpm. The experimental results were obtained for the performance and emission parameters of the emulsion fuelled engine when the engine was subjected to different injection timings, nozzle opening pressures and compression ratios. With respect to the original compression ratio of the engine which was 17.5, one lower (16.5) and one higher compression ratio (18.5) were used in the investigation. Similarly, injection timing was advanced to a maximum of 3 °CA, and the nozzle opening pressure was set at 200, 220 and 240 bar at a regular interval of 20 bar. The results were analysed and compared with those of the normal diesel engine operation and presented in this paper.
The efficiency and CO2 are one of the main concerns of automotive manufacturers. There are several strategies under investigation to solve this problem. In the present work, the research effort has been focused on improving knowledge of in-cylinder heat transfer and its impact on engine efficiency. In particular, soot radiation was studied since it can be considered a significant source of the efficiency losses in modern diesel engines. Considering previous studies, the portion of total chemical energy released during combustion lost due to radiation heat transfer varies widely from 0.5% up to 10%, depending on engine parameters and combustion process. Thus, the main objective of this work was to evaluate the amount of energy lost to soot radiation relative to the input fuel chemical energy during the combustion event under different operating conditions in a completely controlled environment provided by an optical engine. Under these simplified conditions, two-color method was applied by using high speed imaging pyrometer with cameras (two dimensional results) and optoelectronic pyrometer (zero dimensional results). Once a detailed comparison between both diagnostics was performed, optoelectronic pyrometer was used to characterize radiant energy losses in a fully instrumented 4-cylinder direct-injection light-duty diesel engine. In particular swirl ratio, EGR and combustion phasing effects on radiation heat transfer were evaluated.
Abstract
Energy and environment play important role in sustainable development of the world. A continuous research is going on to harness energy from various sources of energy and also reduce the greenhouse gases (GHG) that cause global warning. Despite there is a more focus on utilisation of liquid and gaseous fuels for internal combustion (IC) engine applications, there has also been a continuous interest on utilisation of solid fuels for the same. This paper presents the review of research works pertaining to characterisation and utilisation of different solid fuels such as coal, charcoal, carbon nanotube blended with biofuel, nanoadditive blended fuels, carbon black based fuels and biomass based solid fuels used in compression ignition (CI) engine applications.
Carbon black (CB) is one of the products obtained from waste tyre recycling plant and possesses considerable energy in it. In this investigation, the CB was used as an energy source in a diesel engine. An emulsion CBWD10 containing 10% CB, 3% Water, 2% Surfactant and 85% Diesel in it on volume basis was used as an alternative fuel in a single cylinder, four stroke, DI diesel engine. The engine behaviour in terms of combustion, performance, and emission was evaluated by varying the injection timing and nozzle opening pressure. Results indicated that the maximum heat release rate of 57.7 J/°CA was recorded with the CBWD10 emulsion at 220 bar with 26°bTDC, which was higher by about 5.38% than that of diesel fuel at full load. The brake thermal efficiency (BTE) of the engine fuelled with the emulsion was maximum higher by about of 4% at an advanced injection timing of 26obTDC and 220 bar nozzle opening pressure. The results also indicated that the CBWD10 emulsion at all injection timings and nozzle opening pressures exhibited the NO emissions lower by about 16 – 42% than that of diesel operation at full load.
In this investigation, CB (Carbon black) was doped with diesel by following certain sequential processes and the mixture was commonly referred to as Carbodiesel. The mixture containing 5% CB was denoted as Carbodiesel5. Similarly, 10%, 15% and 20% CB in Carbodiesel were denoted as Carbodiesel10, Carbodiesel15 and Carbodiesel20 respectively. All the four Carbodiesels were used as alternative fuels in a single cylinder, four stroke, air cooled, DI (direct injection) diesel engine. The engine behaviour in terms of combustion, performance and emissions of the engine fuelled with the four Carbodiesels was evaluated and compared with those of diesel operation. The results indicated that Carbodiesel10 gave better performance and lower emissions compared to those of Carbodiesel15 and Carbodiesel20 at full load. The nitric oxide (NO) emission for Carbodiesel10 was found to be lower by about 6.2% than that of diesel at full load, while the smoke density was found to be higher by about 11.5% than that of diesel at full load. The engine can run on Carbodiesels without any major engine modification.
Carbon black (CB) is one of the products obtained from the pyrolysis of waste automobile tyres. It possesses a considerable amount of heat energy in it. In this research work, the effect of varying injection timing on the combustion, performance and emissions of a single cylinder, air cooled, four-stroke, direct injection (DI) diesel engine was experimentally investigated, by using a synthetic fuel blend. The synthetic fuel blend was composed of 10% CB and 90% diesel on a volume basis and was denoted as Carbodiesel10. Investigations were carried out with Carbodiesel10 at different injection timings, viz; original (23°CA bTDC), two advanced (26°CA bTDC and 24.5°CA bTDC) and retarded (21.5°CA bTDC and 20°CA bTDC) injection timings. With the advanced injection timing of 26°CA bTDC, the brake thermal efficiency was found to be higher by about 6.4% while the fuel consumption was found to be lower by about 11.9% than those of the original injection timing. The NO emission was noticed to be higher by about 23% and the smoke was lower by about 13.5% at 26°CA bTDC than that of the original injection timing.
Carbon black (CB), a solid waste obtained from the pyrolysis of waste automobile tyres possesses a considerable heating value in it. In this study, four different emulsions of CB, diesel and water were prepared with the help of a surfactant, by varying the percentages of the CB. An emulsion containing 5% CB was denoted as CBWD5. Similarly, 10%, 15% and 20% CB in emulsion were denoted as CBWD10, CBWD15 and CBWD20, respectively. The emulsion were characterised for their suitability as fuels. Further, they were tested as alternative fuels in a single cylinder, air cooled, direct injection (DI), diesel engine developing power of 4.4 kW at 1500 rpm. The combustion, performance and emission characteristics of the diesel engine fueled with the four different emulsions were compared with the diesel operation of the same engine. The engine was able to run with all the four emulsions without any modification in the engine. The results indicated that the emulsions exhibited longer ignition delay about 1–3°CA, compared to that of diesel at full load. The brake specific energy consumption (BSEC) was higher by about 0.8–25% with the emulsions than that of diesel at full load. The results also indicated that all the emulsions gave lower NO emissions by about 16–42% at full load.
This paper studies the characteristics of blends of biodiesel and a new type of SSPO (sewage sludge derived intermediate pyrolysis oil) in various ratios, and evaluates the application of such blends in an unmodified Lister diesel engine. The engine performance and exhaust emissions were investigated and compared to those of diesel and biodiesel. The engine injectors were inspected and tested after the experiment. The SSPO-biodiesel blends were found to have comparable heating values to biodiesel, but relatively high acidity and carbon residue. The diesel engine has operated with a 30/70 SSPO-biodiesel blend and a 50/50 blend for up to 10 h and there was no apparent deterioration in operation observed. It is concluded that with 30% SSPO, the engine gives better overall performance and fuel consumption than with 50% SSPO. The exhaust temperatures of 30% SSPO and 50% SSPO are similar, but 30% SSPO gives relatively lower NOx emission than 50% SSPO. The CO and smoke emissions are lower with 50% SSPO than with 30% SSPO. The injectors of the engine operated with SSPO blends were found to have heavy carbon deposition and noticeably reduced opening pressure, which may lead to deteriorated engine performance and exhaust emissions in extended operation.
In order to solve the failure of fuel system when using petroleum coke oil slurry (PCOS) in a R180 diesel engine directly, a petroleum coke oil slurry fuel system (PCOSFS) was developed and installed in R180 engine, which was called PCOS engine. In order to analyze performances and emissions of the PCOS engine, a comparative experiment between PCOS engine fueled with PCOS and R180 engine fueled with diesel oil was carried out. The results show that the PCOS engine can run smoothly, the maximum output power decreases by about 6.2% and 19.0% and the maximum brake thermal efficiency reduces by around 5.85% and 4.13% as compared to R180 engine under the conditions of 1 200 and 1 600 r/min. The HC emissions of PCOS engine are lower than those of R180 engine at 1 200 r/min, and are close to those of R180 engine at 1 600 r/min. The CO emissions are similar to R180 engine at 1 200 and 1 600 r/min. The smoke intensity is close to R180 engine at 1 200 r/min, and is higher than R180 engine at 1 600 r/min. The particles emitted from PCOS engine array sparsely, but particles emitted from R180 engine array closely, cohering together.
This paper presents a work on biomass torrefaction performed in a laboratory unit with a reactor tube of a length of 0.5 m and an inner diameter of 0.04 m). The experiments are conducted with two species of wood, birch and pine, and sugar cane bagasse. The reactor was heated to the selected temperature (230°C, 250°C or 280°C) and kept at the final temperature for a period of 1, 2 or 3 hours. The effect of the raw material, temperature, residence time and nitrogen flow on the properties of the torrefied products is studied. The torrefied biomass products are characterized with elemental composition, energy content, moisture content, ash content, volatile fraction. The gaseous products are also analysed. The type of biomass influenced the product distribution. During torrefaction biomass undergoes changes in physical and chemical properties. The fixed carbon content and energy density increase with both time and temperature of torrefaction, while the yield on a weight basis decreases. The torrefied biomass has hydrophobic properties and a higher calorific value than the raw material.
The effects of carbon black/diesel fuel slurries on fuel injection systems and performance of an EMD 567B two-cylinder locomotive research engine when operated on slurry fuel are presented in this paper. Without extensive modification to the diesel engine fuel transfer system, carbon black slurries cannot be run. Laboratory bench tests revealed clogged fuel filters, worn transfer pump components and frozen injector needle assemblies. Engine performance while running slurries resulted in reduced thermal efficiency and increased BSFC at rated power output. Upon engine disassembly, inspection revealed severe ring and liner wear. Severe wear resulted during only 40 hours of engine operation.
The authors investigated the formulation, combustion and emissions of polypropylene (PP)–diesel fuel mixtures in a direct injection diesel engine. The fuel has been obtained by an original technology they developed, in which the low or high density polypropylene (LDPP, HDPP), have been mixed in a nitrogen atmosphere at 200 °C, 10–40% by wt. in diesel fuel. The kinematic viscosity of the polypropylene-diesel fuels was investigated between 25–250 °C and the results showed that viscosity of the plastic mixtures is much higher than that of diesel alone, ranging from 10 cSt to 500 cSt, and depending on the plastic structure, content, and temperature. The TGA and DTA analysis has been conducted to investigate the oxidation and combustion properties of pure PP and polymerdiesel fuels. The results showed that at about 125 °C, the LDPP melts, but does not decompose up 240 °C, when the oxidation starts, and has a peak of heat release at 340–350 °C, and the process is completed at 400 °C. The engine’s injection system used, was a piston-barrel type pump, capable of an injection pressure of 200 bars. The injector had 4 × 0.200 mm nozzles with a conical tip needle. The 25% PP-diesel mixture had a successful ignition in a direct injection 110 mm bore, omega combustion chamber engine. The ignition delay for polypropylene-diesel mixtures was longer by about 0.5 ms (at 1200 rpm), compared with diesel. The heat release showed a different development compared with the reference diesel fuel, the premixed phase being inhibited while a slow diffusion combustion phase fully developed. The maximum combustion pressure has been 83 bars for diesel and decreased by 2 bars for the blended fuel, while the bulk gas maximum temperature (calculated) reached about 2500 K for diesel vs 2600 K for polypropylene mixture. The heat flux calculated by the Annand model has shown lower values for diesel fuel with a maximum of about 2.7 MW/m2 compared with 3.0 MW/m2 for PP blended fuel with similar values for convection flux for both fuels at about 1.57 MW/m2 and a higher radiation flux of about 1.44 MW/m2 for PP fuel versus 1.27 MW/m2 for diesel. The heat lost during the cycle shows low values for the premixed combustion stage and increased values for the diffusion stage for both fuels. The exhaust temperatures have been practically identical for both fuels for all loads, with emissions of NOx, and CO reduced by 40% for the alternative fuel, while the CO2 exhibited almost the same values for both fuels. The smoke emissions decreased by 60–90% for the polypropylene blended fuel depending on the load, The engines’ overall efficiency was slightly lower for PP fuel at low loads compared with diesel combustion but at 100% load both reached 36%. The study showed that the new formulation process proposed by the authors is able to produce a new class of fuels from diesel blended with low density polypropylene, and resulted in hybrid fuels with very promising combustion prospects. The engine investigation proved that 25% PP fuels can be injected and burnt in a diesel engine at a residence time of about 5 ms from the start of injection, and the engine’s nominal power could be reached, with lower emissions than reference diesel fuel.
The paper presents the research on biomass coal-oil mixture (Bio-COM) and its use an alternative fuel for combustion in diesel generating plants. The employment of Bio-COM fuel intends to reduce heavy fuel oil consumption and would reduce green house emissions into the atmosphere. In the experiments, wood chips were used for the production of charcoal that was successfully emulsified with HFO-A. The results of the laser investigations in sprays of Bio-COM show the fuel, non-Newtonian fluid, is able to atomise well. The combustion of the new fuels was investigated in a diesel engine and showed that Bio-COM fuels can be burned with efficiency. Finally, the emissions of Bio-COM were better at optimized injection timing than those of HFO-A with the original engine settings. It is demonstrated that the new emulsification process proposed in this paper is able to produce fuels from biomass charcoal and HFO-A, for diesel generation plants.
In this paper a new system which has the capacity to inject and control the combustion of coal slurries in diesel engines is described. The system eliminates the negative impact of coal slurries on the injection process, improves combustion of coal slurries, eliminates or greatly reduces the wear of the fuel delivery hardware, and prevents the nozzle clogging.
Four major coal fuel projects which were performed at Southwest Research Institute over the past ten years are reviewed. Beginning with the Alternative Fuels for Highway Utilization project in 1979, and the success of carbon-black/diesel fuel slurries, the development of the coal slurries is traced to the current technology. Most recently, full-scale locomotive engines have been operated on 50% coal in water slurries at thermal efficiencies approaching that of diesel fuel performance. The paper is concluded with a recommended engine design for coal slurries.
This analysis developed detailed process flow diagrams and an Aspen Plus{reg_sign} model, evaluated energy flows including a pinch analysis, obtained process equipment and operating costs, and performed an economic evaluation of two process designs based on the syngas clean up and conditioning work being performed at NREL. One design, the current design, attempts to define today's state of the technology. The other design, the goal design, is a target design that attempts to show the effect of meeting specific research goals.
Engine results using biofuels have varied considerably in the reported literature. This article addresses two potential sources of this variation, atomization differences and impurities due to lack of quality control during production. Atomization is the first process encountered during the combustion of fuels in a compression ignition engine and is largely determined by the fuel's viscosity and surface tension. Previous work using five experimentally produced methyl ester biodiesel fuels showed that the viscosity and surface tension could be predicted from their fatty acid ester composition, and the atomization characteristics in turn could be predicted from their viscosity and surface tension. This article utilizes the results of that work to give a quantitative comparison of the atomization characteristics of fifteen biodiesel fuel types using the fuel's viscosity and surface tension, predicted directly from the fatty acid composition of the fuels. Except for coconut and rapeseed biodiesel fuels, all of the rest of the 15 biodiesel fuels had similar atomization characteristics. Since the most likely contaminant in the fuel from the processing was residual glycerides, their effect on viscosity and surface tension was studied experimentally and their effect on the atomization characteristics was computed.
Measurements of instantaneous heat transfer rates from the working fluid to the cylinder head of a small open-chamber, four-stroke, compression-ignition engine have been made at five points on the surface, using a new form of thin-film thermocouple. These observations demonstrate that flux magnitude and the form of flux variation during the cycle depend greatly on local conditions. Some of the observed phenomena are explained qualitatively. Finally, some results are presented of an analysis of fluxes averaged over all five locations, in terms of the bulk mean properties of the working fluid. It is shown that some compensation for the non-steady nature of the situation may be given by adding to the usual type of quasi-steady relation a term involving the time derivative of the bulk mean temperature.
The U.S. Department of Energy (DOE) Office of Fossil Energy has sponsored research in the area of coal-fueled diesel engines since the late 1970s. The program began as an exploratory effort and has grown into a proof-of-concept program that includes several major medium-speed diesel engine manufacturers. Those manufacturers have identified the utility, industrial cogeneration, and transportation markets as areas in which expensive clean distillate fuel may be displaced by low-cost, domestically abundant coal. The development of coal fuels, engine components, wear and emission control system, and a support infrastructure. Because of success in earlier projects of the coal-fueled diesel program, the DOE's Morgantown Energy Technology Center (METC) recently expanded the program with the award of contracts for two 5-year, proof-of-concept project. These projects will build on the results of past work to complete development of technology for the commercialization of coal-fueled diesel engines. This paper summarizes progress in the DOE program and planned research to overcome technical and economic barriers to that commercialization.
Practical use of coal-fueled diesel engines depends on the improvement of component durability. The wear characteristics of standard materials in the coal-fueled engine were studied first. Candidate wear-resistant materials were sorted by bench-scale tests. The best material combinations were applied to small-scale engine tests for operation on seeded diesel fuel. Components with hard materials and coatings were scaled up for coal-water mixture testing on the locomotive engine. Results indicate practical solutions for ring and liner wear and positive progress toward defining the material requirements for the fuel injection nozzle.
This work addresses a policy initiative by the Federal Administration to apply United States Department of Energy (DOE) research to broadening the country's domestic production of economic, flexible, and secure sources of energy fuels. President Bush stated in his 2006 State of the Union Address: "America is addicted to oil." To reduce the Nation's future demand for oil, the President has proposed the Advanced Energy Initiative which outlines significant new investments and policies to change the way we fuel our vehicles and change the way we power our homes and businesses. The specific goal for biomass in the Advanced Energy Initiative is to foster the breakthrough technologies needed to make cellulosic ethanol cost-competitive with corn-based ethanol by 2012. In previous biomass conversion design reports by the National Renewable Energy Laboratory (NREL), a benchmark for achieving production of ethanol from cellulosic feedstocks that would be "cost competitive with corn-ethanol" has been quantified as 1.07 per gallon ethanol minimum plant gate price. This process design and technoeconomic evaluation addresses the conversion of biomass to ethanol via thermochemical pathways that are expected to be demonstrated at the pilot-unit level by 2012. This assessment is unique in its attempt to match up: • Currently established and published technology. • Technology currently under development or shortly to be under development from DOE Office of Biomass Program funding. • Biomass resource availability in the 2012 time frame consistent with the Billion Ton Vision study. Indirect steam gasification was chosen as the technology around which this process was developed based upon previous technoeconomic studies for the production of methanol and hydrogen from biomass. The operations for ethanol production are very similar to those for methanol production (although the specific process configuration will be different). The general process areas include: feed preparation, gasification, gas cleanup and conditioning, and alcohol synthesis & purification. The cost of ethanol as determined in this assessment was derived using technology that has been developed and demonstrated or is currently being developed as part of the OBP research program. Combined, all process, market, and financial targets in the design represent what must be achieved to obtain the reported 1.01 per gallon, showing that ethanol from a thermochemical conversion process has the possibility of being produced in a manner that is "cost competitive with corn-ethanol" by 2012. This analysis has demonstrated that forest resources can be converted to ethanol in a cost competitive manner. This allows for greater flexibility in converting biomass resources to make stated volume targets by 2030.
Coal-water-slurry (CWS) engine tests designed to evaluate a new accumulator-based injection system are described in this paper The new injection system was found to improve CWS burnout considerably at both full and part engine loads. The peak cylinder firing pressure when operating with CWS was no higher than when operating with diesel oil. These data demonstrates the improved engine performance that can be achieved with the accumulator-based injection system.
This report describes the progress and findings of a research program aimed at investigating the combustion characteristics of dry coal powder fueled diesel engine. During this program, significant achievements were made in overcoming many problems facing the coal-powder-fueled engine. The Thermal Ignition Combustion System (TICS) concept was used to enhance the combustion of coal powder fuel. The major coal-fueled engine test results and accomplishments are as follows: design, fabrication and engine testing of improved coal feed system for fumigation of coal powder to the intake air; design, fabrication and engine testing of the TICS chamber made from a superalloy material (Hastelloy X); design, fabrication and engine testing of wear resistant chrome oxide ceramic coated piston rings and cylinder liner; lubrication system was improved to separate coal particles from the contaminated lubricating oil; control of the ignition timing of fumigated coal powder by utilizing exhaust gas recirculation (EGR) and variable TICS chamber temperature; coal-fueled engine testing was conducted in two configurations: dual fuel (with diesel pilot) and 100% coal-fueled engine without diesel pilot or heated intake air; cold starting of the 100% coal-powder-fueled engine with a glow plug; and coal-fueled-engine was operated from 800 to 1800 rpm speed and idle to full load engine conditions.
Slurry fuels of various forms of solids in diesel fuel were develoted and evaluated for their relative potential as fuel for diesel engines. Thirteen test fuels with different solids concentrations were formulated using eight different materials. The injection and atomization characteristics (transient diesel sprays) of the test fuels were examined in a spray bomb in which a nitrogen atmosphere was maintained at high pressure and temperature, 4.2 MPa and 480/sup 0/C, respectively. The diagnostics of the sprays included high-speed movies and high-resolution still photographs. The slurries were also tested in a single-cylinder CLR engine in both direct-injection and prechamber configurations. The data included the normal performance parameters as well as heat release rates and emissions. In most cases, the slurries performed very much like the baseline fuel. The combustion data indicated that a large fraction (90 percent or more) of the solids were burning in the engine. It appears that the prechamber engine configuration is more tolerant of the slurries than the direct-injection configuration.
Three different carbon blacks were used to formulate nine different slurries in DF-2. The rheological properties of each formulation were examined to determine deviations from Newtonian behavior. The spray characteristics of selected formulations were then examined in a highpressure, high-temperature injection bomb. The cone angle decreased and the penetration rates increased for all of the slurries tested as compared to straight DF-2. These changes were more pronounced as the concentration of carbon black increased. Six formulations of three types of carbon black were tested in a single-cylinder, direct injection CLR engine. Apparent heat release rates were computed as a function of crankangle from the cylinder pressure data. Based on the engine performance tests and some limited durability testing it appears that wellformulated carbon black slurries have only minor effects on engine performance and durability.
Autoignition of coal-water-slurry (CWS) fuel in a two-stroke engine operating at 1900 RPM has been achieved. A Pump-Line-Nozzle (PLN) injection system, delivering 400mm{sup 3} injection of CWS, was installed in one modified cylinder of a Detroit Diesel Corporation (DDC) 8V-149TI engine, while the other seven cylinders remained configured for diesel fuel. Coal Combustion was sustained by maintaining high gas and surface temperatures with a combination of hot residual gases, warm inlet air admission, ceramic insulated components and increased compression ratio. The coal-fueled cylinder generated 85kW indicated power (80 percent of rated power), and lower NO{sub x} levels with a combustion efficiency of 99.2 percent. 6 refs., 15 figs., 4 tabs.
The present reserves of liquid petroleum fuels indicate that it may not last for longer period. It has become necessary to search for an alternative fuel which can be used in the present engines. Coal, having large reserves and being abundantly available in India comes to be the first choice. This paper considers steps necessary for making ability of normal engines to accept coal fuels. The program for development of the coal fueled engine has an initial stage of feasibility validation. Some specific areas were selected for investigations of this stage. The investigations were proceeded in sequence of study of the literature and systems, solid fuels and preparation specially suitable for conditions in India. The fuel feed system was developed for the above engine. The initial assessment of combustion process of the coal fuels in the engine was performed with the help of analytical and experimental method. The different systems to be used for coal-fueled engines were analysed on the basis of the literature, theoretical and experimental results. The study demonstrates the possibility of operation of these engines in Indian conditions.
Conventional diesel engines are considered by some to be contributors to environmental problems since they emit NO{sub x}, a suspected acid rain precursor. Initial testing has shown that CWS-fueled diesels emit substantially reduced NO{sub x} emissions. While emissions of particulates and SO{sub x} may be potentially higher with coal fuels, assessment of the control technology indicates excellent potential for meeting existing and future standards for these emissions. As a result of activities managed by the Morgantown Energy Technology Center, the economic and technical feasibility of CWS-fueled diesel engines has been determined. The development of CWS-fueled systems will necessitate the application of hot gas cleanup contaminant control technology to ensure that the systems burn coal in an environmentally sound manner. The objective of this paper is to discuss the environmental concerns, emission goals, and the control methodologies, devices, and strategies that will be used to ensure CWS-fueled diesel engines will meet current and potential environmental standards.
Objectives • To determine the economics of hydrogen production by gasification of three biomass candidates: bagasse, switchgrass, and nutshells • To optimize hydrogen production for use in proton exchange membrane (PEM) fuel cells • To identify the economic and technical barriers associated with biomass gasification Technical Barriers This project addresses the following technical barriers from the Hydrogen Production section of the Hydrogen, Fuel Cells and Infrastructure Technologies Program Multi-Year R,D&D Plan: • F. Feedstock Cost and Availability • G. Efficiency of Gasification, Pyrolysis, and Reforming Technology • AB.Hydrogen Separation and Purification Approach • Determine the cost and availability of the three candidate biomass feedstocks. • Design a process scheme for the production of hydrogen. • Determine optimal hydrogen production through the testing of various simulation cases. • Analyze research and simulation results to determine technical and economic feasibility. • Determine the commercialization barriers to the production of hydrogen from biomass. Accomplishments • Estimated the cost and availability of all three biomass feedstocks. • Determined the current technologies available for biomass feeding and hot gas cleanup. • Simulated and optimized the production of hydrogen through the use of an empirical, GTI proprietary gasifier model and a HYSYS design and simulation package. • Performed an economic analysis of the production of hydrogen from the three biomass feedstocks. • Evaluated current public programs available to reduce the cost of biomass as a feedstock. • Determined the technical, economic, and psychological barriers to the commercialization of hydrogen from biomass.
Our current understanding of the mechanisms and rate parameters for the gas-phase reactions of nitrogen compounds that are applicable to combustion-generated air pollution is discussed and illustrated by comparison of results from detailed kinetics calculations with experimental data. In particular, the mechanisms and rate parameters for thermal and prompt NO formation, for fuel nitrogen conversion, for the Thermal De-NOx and RAPRENOx processes, and for NO2 and N2O formation and removal processes are considered. Sensitivity and rate-of-production analyses are applied in the calculations to determine which elementary reactions are of greatest importance in the nitrogen conversion process. Available information on the rate parameters for these important elementary reactions has been surveyed, and recommendations for the rate coefficients for these reactions are provided. The principal areas of uncertainty in nitrogen reaction mechanisms and rate parameters are outlined.
The introduction to this review outlines the reassons why engine heat transfer is important, but also very complex. As can be understood from the review, the current status of both experimental and theoretical findings leaves much to be done. In the following we will try to briefly summarize the status quo and indicate what we feel needs to be done for future research.
1. The larvae of four swallowtail butterfly species, Papilio polyxenes Fabr. in the Papilionini, Parides bunichus (Hübner) and Battus polydamas (L.) in the Troidini, and Eurytides marcellus (Cramer) in the Graphiini, were grown on host leaves to which test compounds had been added.
2. The test chemicals are biosynthetically related. Berberine, a 1-benzyl-tetrahydroisoquinoline-related (1-BTIQ) alkaloid, is found in many rutaceous hosts of the Papilionini; laudanosine, a simpler 1-BTIQ alkaloid, is found in the Papaveraceae, plants on which no papilionids feed; aristolochic acids are found only in the Aristolochiaceae, hosts of the Troidini.
3. Swallowtail larvae can tolerate the compounds characteristic of their host plants, but not chemicals found in the hosts of other papilionid groups. Diets with laudanosine did not affect the test species.
4. Our results support the contention that plant secondary chemicals, such as berberine and aristolochic acids, are important feeding barriers, and are partially responsible for host specificity in swallowtails.
Transportation's role in reducing U.S. greenhouse gas emissions
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Numerical evaluation of the carbonewater reaction in a coalewater reaction in a coalewater fueled engine
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Injection and atomization of coalewater slurry in high pressure diesel environment
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Study of cetane number and aromatic content effects on regulated emissions from a heavy-duty engine. Coordinating Research Council Contract VE-1
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Ullman T, Mason R, Montalvo D. Study of cetane number and aromatic content effects on regulated emissions from a heavy-duty engine. Coordinating Research Council Contract VE-1. San Antonio, TX: Southwest Research Institute; 1990.
Biomass as a source of energy
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Biomass Gasification: experience and current projects. In: Inter-national Seminar on Gasification e Production Technologies, Sweden. GTI
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Vann Bush. Biomass Gasification: experience and current projects. In: Inter-national Seminar on Gasification e Production Technologies, Sweden. GTI; 2008.
Integrated gasification combined cycles and advanced concepts for biomass power generation. In: Annual California Biomass Collaborative Forum
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Lau F. GTI Integrated gasification combined cycles and advanced concepts for biomass power generation. In: Annual California Biomass Collaborative Forum; 2005.
Affordable, low-carbon diesel fuel from domestic coal and biomass
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Tarka TJ. Affordable, low-carbon diesel fuel from domestic coal and biomass, DOE/NETL-2009/1349. http://www.netl.doe.gov/energy-analyses/pubs/CBTL% 20Final%20Report.pdf.
Life-cycle greenhouse-gas emissions inventory. For FischereTropsch fuels
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Indirectly heated biomass gasification. NREL
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Bain R. Indirectly heated biomass gasification. NREL; 2009.
The development of a new emulsified alternative fuel for diesel power generation produced from waste plastics
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Soloiu VA, Yoshihara Y, Nishiwaki K, Kako T, Hiraoka M. The development of a new emulsified alternative fuel for diesel power generation produced from waste plastics. In: CIMAC Kyoto; 2004.
The Impact of a polyethyleneediesel blended fuel on combustion and emissions in a compression ignition engine
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- Nishiwaki
Soloiu V, Yoshihara Y, Nishiwaki K. The Impact of a polyethyleneediesel blended fuel on combustion and emissions in a compression ignition engine. SAE 2010-01-0475. In: SAE World Congress, Detroit; 2010.