Academic literature on the topic 'Unburned product'
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Journal articles on the topic "Unburned product"
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Gurusingam, Pogganeswaran, Firas Basim Ismail, and Taneshwaren Sundaram. "Operating Parameter Optimization using DOE Method to Reduce Unburned Carbon of Fly Ash for Tangential Fired Subcritical Coal Fired Power Plant." MATEC Web of Conferences 225 (2018): 05008. http://dx.doi.org/10.1051/matecconf/201822505008.
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As electric demand increasing due to rapid economic growth, most developing country are sourcing for cheap fuel and low maintenance power plant which coal fired power plant become the more preferable plant. The cheap and abundant coal resources have played a major factor for coal power plant selection compare to other type of power plant. Although this plant type has low maintenance and operating cost but its emission of by product has a great effect on daily plant operation and environment. The one of the major emission was unburned carbon which by product of incomplete combustion where remaining of coal that unburned exits the furnaces with ash. Presence of higher percentage of unburned carbon indicates the low efficiency of furnace combustion and this directly affects financial status of the power plant operators. This condition causes severe damages on the boiler tube by formation of slagging and clinkering which reduces heat transfer and efficiency of the furnace. Current method proved to be more time consuming and plant operator facing difficulty to reduce unburned carbon in real time. As a solution for this problem, a best parameter was predicted to achieve low percentage of unburned carbon.
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Wu, Yu Shiang, Tzuo Shing Yeh, and Yuan Haun Lee. "Improving the Rate Capability of Unburned Carbon from Oil-Fired Fly Ash as an Anode Material in High-Power Lithium Ion Batteries." Advanced Materials Research 287-290 (July 2011): 1304–7. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.1304.
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Unburned carbon is an industrial waste product of oil-fired fly ash. Recycled ground unburned carbon with an average particle size of 5 μm after heat treatment at 2500°C displayed an first coulombic efficiency of approximately 89.8% at a charge and discharge rate of 0.1 C. The discharging capacity of this type of carbon was 293.7 mAhg-1, and its capacity retention was approximately 94.7% after 50 cycles. However, the first coulombic efficiency of ground unburned carbon receiving nitric acid treatment after heat treatment increased to 91.1%, its discharging capacity increased to 318.6 mAhg-1, and its capacity retention increased to 98.5% after 50 cycles. Rate capability tests show that the unburned carbon after heat treatment exhibited a higher capacity in the lower C-rate region (0.2~3 C) at a 0.2 C rate charge and variable C-rates discharge. However, unburned carbon with nitric acid treatment is a suitable material for the higher C-rate region (5~10 C). Unburned carbon after heat treatment exhibited a higher capacity in the lower C-rate region (0.2~0.5 C) at the same C-rate charge and discharge.
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Zhang, Sheng Bing, Yi Liu, Yan Hong Zhang, and Hua Lin Wang. "Experimental Study on Classification of High Carbon Fly Ash with a Hydrocyclone." Advanced Materials Research 955-959 (June 2014): 2779–84. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.2779.
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The fly ash has a wide range of particles size and has a large amount of unburned carbon. As a raw material, the presence of the large particles and the unburned carbon will reduce the quality of the product. How to improve the utilization of fly ash has become one of focus points. In this work, hydrocyclone was adopted for classification after decarburization in a flotation column. Hydrocyclone showed a very good classification performance. In overflow, the particles were all smaller than 85μm. About 97.34% of the particles were smaller than 25 μm. Different fly ash content was selected to investigate its influence on the decarburization. The results showed that it made no obvious differences.
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McCarley, T. Ryan, Alistair M. S. Smith, Crystal A. Kolden, and Jason Kreitler. "Evaluating the Mid-Infrared Bi-spectral Index for improved assessment of low-severity fire effects in a conifer forest." International Journal of Wildland Fire 27, no. 6 (2018): 407. http://dx.doi.org/10.1071/wf17137.
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Remote sensing products provide a vital understanding of wildfire effects across a landscape, but detection and delineation of low- and mixed-severity fire remain difficult. Although data provided by the Monitoring Trends in Burn Severity (MTBS) project are frequently used to assess severity in the United States, alternative indices can offer improvement in the measurement of low-severity fire effects and would be beneficial for future product development and adoption. This research note evaluated one such alternative, the Mid-Infrared Bi-Spectral Index (MIRBI), which was developed in savannah ecosystems to isolate spectral changes caused by burning and reduce noise from other factors. MIRBI, differenced MIRBI (dMIRBI) and burn severity indices used by MTBS were assessed for spectral optimality at distinguishing severity and the ability to differentiate between unburned and burned canopy in a conifer forest. The MIRBI indices were better at isolating changes caused by burning and demonstrated higher spectral separability, particularly at low severity. These findings suggest that MIRBI indices can provide an enhanced alternative or complement to current MTBS products in high-canopy-cover forests for applications such as discernment of fire perimeters and unburned islands, as well as identification of low-severity fire effects.
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Svietkina, Olena, Hanna Tarasova, Olha Netiaha, and Svitlana Lysytska. "Ash as an alternative source of raw materials." E3S Web of Conferences 60 (2018): 00026. http://dx.doi.org/10.1051/e3sconf/20186000026.
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The objective of the work is to study the aluminosilicate fractionation from fly ash, physical and mechanical properties of fly ash derived from the Thermal Power Plants (TPP) wastes. Ash, carbon concentrate (unburned carbon), ash concentrate and products of their treatment with reagents were tested by optical methods. The particle morphology of the objects of research was studied with the scanning electron microscope REM-100. The composition of the ash phases was investigated using the X-ray diffractometer DRON-2. A dispersed analysis of the TPP fly ash suggests a conclusion that it is advisable to separate particles of a narrow grain-size class within the range from 40 to 150 μm with an ash content of about 33%. The first product may be enriched by flotation method. Such a coal product may be used as a reducing medium in metallurgical processes, agglomeration, etc. The calorific capacitance of the concentrate is about 6000 kcal/kg (25000 kJ/kg).
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Pahl, James W., Irving A. Mendelssohn, and Thomas J. Hess. "THE APPLICATION OF IN-SITU BURNING TO A LOUISIANA COASTAL MARSH FOLLOWING A HYDROCARBON PRODUCT SPILL: PRELIMINARY ASSESSMENT OF SITE RECOVERY." International Oil Spill Conference Proceedings 1997, no. 1 (April 1, 1997): 823–28. http://dx.doi.org/10.7901/2169-3358-1997-1-823.
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ABSTRACT The high degree of physical disturbance associated with conventional responses to oil spills in wetlands is driving the search for alternative cleanup methodologies. In March 1995, in southwestern Louisiana, a spill of gas condensate product into a brackish marsh at Rockefeller Wildlife Refuge was removed by in-situ burning. A monitoring program was established to examine the recovery of the marsh site. Three treatments were examined: (1) condensate-impacted and burned, (2) condensate-impacted and unburned, and (3) a reference that was neither exposed to the condensate nor burned. In March, July, and October 1995, vegetation plots were analyzed for biomass and stem density. Permanent quadrats were surveyed in July and October for total and species-specific percent cover. Although vegetation recovery was apparent 7 months after the burn, the burn treatment resulted in significantly lower biomass and stem density compared with both unburned treatments. In addition, burning led to conditions that favored initial recolonization by the sedge Scirpus robustus in a site previously dominated by the grasses Distichilis spicata and Spartina patens. However, biomass and stem density data suggest that D. spicata is regaining dominance. On the basis of these initial results, observations made in 1996 at the study site, and previous research, it is expected that in-situ burning will be successful at this site.
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Rasmusson, H., S. Sarenbo, and T. Claesson. "Ash Products and Their Economic Profitability." Open Waste Management Journal 6, no. 1 (April 5, 2013): 1–5. http://dx.doi.org/10.2174/1876400201306010001.
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Sustainable whole-tree harvesting practice requires that nutrient removal from the forest is compensated. Wood ashes contain all the nutrients, except for nitrogen, that are found in unburned fuel and can also increase soil pH, which makes ash recycling a natural way to stabilize the nutrient balance and counteract the acidification of forest soils that occurs due to intensive forest management. Several methods for processing ashes into spreadable products have been developed. The aim of this paper is to compare these methods. The study mainly focused on an economic evaluation of production, transportation and the spreading of self-hardened ash, ash pellets and ash granules. Self-hardened ash is generally considered to be the cheapest alternative to manufactured ash products, but these results imply that the most cost effective alternative is ash pellets. Around 27% of total costs could be earned from recycling the ash by producing pellets and 8% if granules are produced instead of self-hardened ash. This partly depends on the higher density of the pellets and granules and a significant reduction in the number of transportation operations. The reduction in transportation operations and diesel consumption also has major environmental benefits. Furthermore, it is more efficient to produce granules and pellets than it is to produce self-hardened ash and it is also easier to produce a reliable product of an appropriate size, shape and texture for a market that has well defined requirements.
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Barcelos, Sheyla Thays Vieira, Ismael Plácido Tomielis, Marli Da Silva Garcia, and Marney Pascoli Cereda. "Characterization of boiler ashes from sugarcane mill." Revista Ibero-Americana de Ciências Ambientais 10, no. 3 (July 17, 2019): 179–90. http://dx.doi.org/10.6008/cbpc2179-6858.2019.003.0016.
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Sugarcane mills produce sugar and ethanol and have always used bagasse as fuel to generate energy for self-consumption. Recently some mills have been also producing surplus electricity to sell in the market a third product from sugarcane. Although any boiler can be efficient, the sale of electricity has stimulated the improvement of the burning process. However, the investment in high-pressure boilers, much more expensive than any common boiler, is essential for the exportation of electricity. Among the 22 sugarcane mills from Mato Grosso do Sul, Brazil, only 12 power plants sell electricity to the grid. The power generation efficiency depends on the pyrolysis in boilers, which results in ashes that match the unburned mineral fraction of the fuel as oxide. Both the bagasse and the straw are composed predominantly of lignin, hemicellulose and cellulose with calorific power near to the wood at the same moisture content. However the bagasse leaves the mill with about 50% of moisture while the straw reaches the industry with about 15% of humidity. This paper characterize the ashes samples from burned bagasse from seven sugarcane mills at Mato Grosso do Sul Brazilian state, to compare the methodology available for use to measure the efficiency of the pyrolysis system. Among these sugarcane mills only two are highlighted by their higher burning efficiency, both of them selling electricity, while the others showed unburned portions characterizing an inefficient system. For these industries the ash content in the ashes showed values compatible with the Superior Calorific Value as an efficiency index for the combustion degree in boilers.
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Zaichenko, Nikolai, Irina Petrik, and Liudmila Zaichenko. "Beneficiated ponded fly ash for concretes with high volume mineral additions." MATEC Web of Conferences 315 (2020): 07006. http://dx.doi.org/10.1051/matecconf/202031507006.
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The article presents the investigation results of effect of beneficiated ponded fly ash on the properties of cement pastes and concretes with high-level replacement of Portland cement. To improve the characteristics of ponded fly ash meeting technical requirements for replacing cement in concrete the triboelectrostatic beneficiation technology has been elaborated. This technology can produce low-carbon ash product (LOI = 2.52 % in this study) for the high replacing level of cement (45 %) in concretes. The beneficiated ponded fly ash has an improved granulometric and phase composition, a decreased content of unburned carbon that accelerates the hydration process of cement, increases the rheological properties of cement paste and the ability of air-entraining admixture to hold the required involved air. In a combination with the nanostructured-carbon-based plasticizing admixture the beneficiated ponded fly ash exhibits high rate of strength increase when is used in high-volume fly ash concretes.
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Roteta, E., and P. Oliva. "OPTIMIZATION OF A RANDOM FOREST CLASSIFIER FOR BURNED AREA DETECTION IN CHILE USING SENTINEL-2 DATA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W12-2020 (November 6, 2020): 337–42. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w12-2020-337-2020.
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Abstract. Due to the high variability of biomes throughout the country, the classification of burned areas is a challenge. We calibrated a random forest classifier to account for all this variability and ensure an accurate classification of burned areas. The classifier was optimized in three steps, generating a version of the burned area product in each step. According to the visual assessment, the final version of the BA product is more accurate than the perimeters created by the Chilean National Forest Corporation, which overestimate large burned areas because it does not consider the inner unburned areas and, it omits some small burned areas. The total burned surface from January to March 2017 was 5,000 km2 in Chile, 20 % of it belonging to a single burned area in the Maule Region, and with 91 % of the total burned surface distributed in 6 adjacent regions of Central Chile.
Dissertations / Theses on the topic "Unburned product"
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Taerakul, Panuwat. "Characterization of trace elements in dry flue gas desulfurization (FGD) by-products." Connect to this title online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1119038889.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xvii, 173 p.; also includes graphics Includes bibliographical references (p. 161-173). Available online via OhioLINK's ETD Center
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Wörner, Ralf. "Oxydation du dibenzofurane : application à l'abattement des dioxines." Vandoeuvre-les-Nancy, INPL, 1997. http://www.theses.fr/1997INPL063N.
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La plupart des procédés thermiques conduisent à la formation de dioxine (PCDD/F) à l'état de traces. Leur toxicité et leur faible biodégradabilité nécessitent de minimiser ces rejets par tous les moyens disponibles (modification du procédé, traitement des émissions, etc. ). Dans le cas des incinérateurs, notre étude bibliographique révèle que la zone de refroidissement des fumées joue un rôle particulièrement important sur la formation des PCDD/F. Des études approfondies effectuées sur des micropilotes ont permis d'identifier trois voies indépendantes conduisant à la formation de ces produits : une formation en phase gazeuse vers 600°C, une formation catalytique en présence de poussières de 300°C à 500°C et finalement la réaction de-novo par gazéification des poussières à 300°C. Nous en avons conclu que seule une amélioration de la combustion permettait de réduire la quantité de PCDD/F émis mais également celle d'autres produits imbrulés indésirables. Nos résultats expérimentaux sur l'oxydation du dibenzofurane en phase gazeuse et à des températures relativement élevées (> 900°C) prouvent que la teneur en oxygène ainsi que le régime d'écoulement sont les paramètres primordiaux et qu'une richesse d'environ 0,8 conduit à une combustion totale des imbrulés. Enfin, nous avons construit un mécanisme détaillé appliqué à l'oxydation du dibenzofurane qui permet d'expliquer qualitativement nos observations expérimentales et qui semble être en bon accord avec les hypothèses faites par d'autres équipes de recherche sur l'oxydation des produits aromatiques à haute température
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Ajrouche, Hussein. "Mesures optiques d'imbrûlés - applications aux émissions des moteurs Diesel et des réacteurs." Rouen, 1995. http://www.theses.fr/1995ROUES021.
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Une méthode optique in situ et non intrusive fondée sur la mesure simultanée de l'extinction et de la diffusion de la lumière par un nuage de particules a été mise au point. Elle a été utilisée pour caractériser le diamètre et la densité particulaire des suies émises par les véhicules Diesel et les turboréacteurs. Nous avons en particulier pu suivre dans un premier temps l'évolution des particules lors des accélérations successives d'un moteur Diesel. Il apparaît que le diamètre croît au cours de l'accélération alors que le nombre de particules tend à décroître. On retiendra comme ordre de grandeur typiques 50 nm et 510. 9 cm cubes à l'intérieur du tunnel. Ces résultats en régime instationnaire, que les méthodes classiques de filtration ne peuvent atteindre, sont à notre connaissance uniques. La première partie du travail a été réalisée au centre technique Citroën, le montage optique était directement fixé au tunnel de dilution recueillant les fumées émises par le pot d'échappement. La deuxième partie du travail décrit une cellule dédiée à la mesure des très faibles quantités d'imbrûlés, ici appliquée aux émissions des turboréacteurs. Compacte, elle utilise deux miroirs de renvoi pour générer un trajet optique total de 150 cm. Dans ces conditions des fractions volumiques inférieures a 10 puissance -8 ont été mesurées et leur évolution suivie en fonction de régime moteur. La discussion met en lumière l'influence des hypothèses faites lors du traitement des données, en particulier celles portant sur l'hypothèse de polydispersion et sur la valeur de l'indice complexe de réfraction des suies. Il est montré que l'usage des différentes valeurs de la littérature peut conduire par exemple à des variations de fraction volumique supérieures à 30%. Il est donc suggéré que l'accent soit mis sur la réduction de ces incertitudes. Sous ces conditions les méthodes optiques dont nous avons montré la faisabilité, y compris sur site industriel, seront un atout précieux dans les études touchant aux émissions d'aérosols et à leur suivi
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Chik, Abdellah. "Etude de la formation de cénosphères au cours de la pyrolyse d'hydrocarbures résiduels." Mulhouse, 1986. http://www.theses.fr/1986MULH0013.
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L'étude est réalisée à l'aide d'un appareil permettant de génerer un chapelet de gouttelettes monodispersées de fuel (par un capillaire soumis à une vibration périodique) et de mesurer les diamètres des gouttelettes avant et après pyrolyse et atmosphère d'azote. Les résultats d'analyse des résidus de carbonisation recueillis à la sortie du four ont été recoupés par des essais à l'échelle semi industrielle, sur huit fuels différents
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Sun, Ping. "Investigation of polycyclic aromatic hydrocarbons (PAHs) on dry flue gas desulfurization (FGD) by-products." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1101932335.
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Thesis (Ph. D.)--Ohio State University, 2004.Document formatted into pages; contains 254p. Includes bibliographical references. Abstract available online via OhioLINK's ETD Center; full text release delayed at author's request until 2005 Dec. 1.
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Jamali, Arash. "Numerical simulation of combustion and unburnt products in dual-fuel compression-ignition engines with multiple injection." Thesis, 2015. http://hdl.handle.net/1805/10827.
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Indiana University-Purdue University Indianapolis (IUPUI)Natural gas substitution for diesel can result in significant reduction in pollutant emissions. Based on current fuel price projections, operating costs would be lower. With a high ignition temperature and relatively low reactivity, natural gas can enable promising approaches to combustion engine design. In particular, the combination of low reactivity natural gas and high reactivity diesel may allow for optimal operation as a reactivity-controlled compression ignition (RCCI) engine, which has potential for high efficiency and low emissions. In this computational study, a lean mixture of natural gas is ignited by direct injection of diesel fuel in a model of the heavy-duty CAT3401 diesel engine. Dual-fuel combustion of natural gas-diesel (NGD) may provide a wider range of reactivity control than other dual-fuel combustion strategies such as gasoline-diesel dual fuel. Accurate and efficient combustion modeling can aid NGD dual-fuel engine control and optimization. In this study, multi-dimensional simulation was performed using a nite-volume computational code for fuel spray, combustion and emission processes. Adaptive mesh refinement (AMR) and multi-zone reaction modeling enables simulation in a reasonable time. The latter approach avoids expensive kinetic calculations in every computational cell, with considerable speedup. Two approaches to combustion modeling are used within the Reynolds averaged Navier-Stokes (RANS) framework. The first approach uses direct integration of the detailed chemistry and no turbulence-chemistry interaction modeling. The model produces encouraging agreement between the simulation and experimental data. For reasonable accuracy and computation cost, a minimum cell size of 0.2 millimeters is suggested for NGD dual-fuel engine combustion. In addition, the role of different chemical reaction mechanism on the NGD dual-fuel combustion is considered with this model. This work considers fundamental questions regarding combustion in NGD dual-fuel combustion, particularly about how and where fuels react, and the difference between combustion in the dual fuel mode and conventional diesel mode. The results show that in part-load working condition main part of CH4 cannot burn and it has significant effect in high level of HC emission in NGD dual-fuel engine. The CFD results reveal that homogeneous mixture of CH4 and air is too lean, and it cannot ignite in regions that any species from C7H16 chemical mechanism does not exist. It is shown that multi-injection of diesel fuel with an early main injection can reduce HC emission significantly in the NGD dual-fuel engine. In addition, the results reveal that increasing the air fuel ratio by decreasing the air amount could be a promising idea for HC emission reduction in NGD dual-fuel engine, too.
Book chapters on the topic "Unburned product"
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Scott, Andrew C. "Getting Dirty: What Charcoal Can tell us." In Burning Planet. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198734840.003.0005.
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Most of us are familiar with charcoal from sketching with it at school, or using charcoal bricks for a barbecue. You will have noticed that it got your hands dirty, that it is brittle, and that it is quite light—at least, lighter than an equivalent piece of uncharred wood. You may also have associated the black residues left after a bonfire with charcoal. If you have been to an area where the vegetation has been destroyed by wildfire, you may have also noticed black residues of charcoal on the ground that make a crunching sound beneath your feet. Our first two examples of charcoal are both products of human manufacture. The bonfire charcoal is a naturally formed material, but still the link with wildfire may not be made. When we see images of burning vegetation it is natural to imagine that all the plant material is consumed by the flames. Yet, as I came to realize on my visit to the site of the Hayman Fire, there is often a significant quantity of unburned material, and charcoal residues as well. Why are we left with charcoal after a fire? Charcoal is produced by heating plant material (most commonly wood, but not exclusively so) in the absence of oxygen. So it isn’t a product of the fire itself, but of the intense heat from the fire. Wood is essentially made up of two organic compounds: cellulose and lignin. Both compounds consist of carbon, hydrogen, and oxygen, but they differ in structure and therefore in properties. In cellulose, the carbon atoms are arranged in straight lines (it is an example of an aliphatic compound). It is the material from which paper is made. In lignin, on the other hand, the carbons are arranged in rings (it is an aromatic compound), and it is this structure that gives wood its toughness and strength. Industrial charcoal is used for a variety of metallurgical processes, and as adsorbents and food additives, as well as for barbecues and artists’ materials, so its formation has been carefully studied.
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Keaveney, Christopher T. "Happy Medium: Re-envisioning the Hero in Japanese Baseball Manga." In Contesting the Myths of Samurai Baseball. Hong Kong University Press, 2018. http://dx.doi.org/10.5790/hongkong/9789888455829.003.0007.
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Chapter 6 considers the cultural medium that constitutes the most substantial body of baseball-themed work in Japan: manga and the related form of anime. Manga emerged as major cultural force at precisely the time in the postwar era that baseball was establishing itself as the unrivaled spectator and participatory sport in Japan. Starting in the Occupation period and continuing to the present, baseball has been a reliable subject for manga practically unrivalled by any other. Starting with the blockbuster success of Kajiwara Ikki’s Star of the Giants in the 1960s and continuing in the work of such luminaries of the manga world as Mizushima Shinji and Adachi Mitsuru, baseball manga and anime adaptations have consistently defined and redefined the hero in cultural terms that represent the values of the age in which they were produced, at times conforming to the cultural myths of Samurai baseball and at other times upending those myths. As the newest forms treated in this study, manga and anime are unburdened by many of the traditional expectations of poetry, fiction or cinema, and continue to offer ideal forms for confronting the fundamental myths associated with Samurai baseball.
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Maun, M. Anwar. "The Ammophila problem." In The Biology of Coastal Sand Dunes. Oxford University Press, 2009. http://dx.doi.org/10.1093/oso/9780198570356.003.0012.
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Even a cursory look on foredune plant communities shows vigorous dense stands of dune species in areas with moderate recurrent sand accretion levels specific for each plant species (Disraeli 1984; Maun and Baye 1989; Maun 1998). The phenomenon has been well documented in species of Ammophila arenaria (Carey and Oliver 1918; Tansley 1953), Corynephorus canescens (Marshall 1965), A. breviligulata (Eldred and Maun 1982) and Calamovilfa longifolia (Maun 1985). Burial has a positive influence on growth and flowering of plants and debilitated populations of foredune plant species can be rejuvenated by sand deposition (Maun 1998). Clear evidence of this phenomenon was presented by Maze and Whalley (1992a), who examined population dynamics of Spinifex sericeus in five zones receiving different amounts of sand deposition on a coastal dune system of Australia: the sea side of the first dune ridge, crest of first dune ridge, swale, Acacia thickets and stable hind dunes. In the very dynamic area on the sea side or toe of the first dune ridge (high beach) with regular burial or erosion of up to 1 m or more the plants produced very vigorous stolons with long internodes. On the crest of the dune ridge with sand deposition of about 17.5 cm per year even though plants had fewer stolons, they responded to burial by growing upwards with long internodes. In Acacia thickets in spite of very little sand deposition, plants were vigorous with little or no dead material, produced stolons and grew upwards with some long and some short internodes, probably because of greater nitrogen content in the soil. However, in the swale (slack) with little or no sand deposition, plants showed strong clumping tendency with very short internodes, a large amount of dead material on the surface and very low vigour. Unburied nodes usually died. Similarly, in the stable sand dunes with little or no sand deposition debilitated low-vigour clumps with very few stolons were abundant. Another example of this decline was presented by Martin (1959) on a shoreline along the Atlantic coast of North Carolina. He measured deposition and deflation of sand on two transects and showed that as one moved inland from the shoreline the total deposition of sand decreased.
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Holliday, Vance T. "Soil Genesis and Site-Formation Processes." In Soils in Archaeological Research. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780195149654.003.0013.
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Pedogenic processes that produce or alter the soils associated with a landscape (buried or unburied) also modify the archaeological sites and other traces of human activity associated with that landscape and buried landscapes. The wide range of processes that form soils can profoundly affect the archaeological record. Pedogenesis, therefore, is an important component of the processes of archaeological site formation. Archaeological “site-formation processes” are those processes that modify artifacts and archaeological sites from the moment they were formed until they are uncovered by archaeologists (Stein, 2001b, pp. 37–38). Understanding formation processes is crucial in archaeology because archaeologists use the patterns of artifacts in the ground to infer behaviors. Formation processes identify patterns that are created by ancient behaviors and separate those patterns from the ones created by later cultural and natural processes (Stein, 2001b, p. 37). In his influential volume Formation Processes of the Archaeological Record, Schiffer (1987, p. 7) notes that archaeologists try to infer past behavior based on the archaeological record, but the record “must be handled with great care by the investigator seeking to infer past behaviors, for the evidence that survives has been changed in many ways by a variety of processes.” These processes introduce variability and ambiguity into the archaeological record. Schiffer (1987, p. 7) further distinguishes between cultural processes, in which the agency of transformation is human behavior, and noncultural processes, which stem from processes of the natural environment. Natural formation processes are many and varied and include plants, animals, wind, water, ice, and gravity, among others. Soil formation is also identified as an important process of site formation. Schiffer (1987) provides a comprehensive discussion of natural site-formation processes, which are summarized by Stein (2001b). Nash and Petraglia (1987) and Goldberg et al. (1993) also provide a number of case histories of natural formation processes identified at archaeological sites. Because soil formation represents the alteration of rock and sediment (chapter 1), pedogenic processes are important natural processes in the formation of archaeological sites. Other weathering processes that are significant in site formation can be grouped as “diagenetic alterations.”
Conference papers on the topic "Unburned product"
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Blanton, John C., and Daniel P. Smith. "Gas Turbine Combustion of a Minimally Cleaned, Coal-Derived Low-BTU Gas." In ASME 1985 International Gas Turbine Conference and Exhibit. American Society of Mechanical Engineers, 1985. http://dx.doi.org/10.1115/85-gt-160.
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As part of the joint GE/DoE Water-Cooled Components Test Program,1 a series of tests were performed involving the combustion of a minimally cleaned low-Btu coal gas in a pressurized gas turbine simulator. The fuel gas was produced in a 1-ton/hr advanced fixed-bed gasifier using Illinois #6 coal, and filtered of particulate in a full-pressure, full-temperature cyclone separator. The resulting product had a gross heating value of approximately 5000 kJ/kg at a temperature of 540 °C and a pressure of 22 bar. Numerous contaminants also remained in the fuel gas, including approximately 100 ppmw particulate matter (coal dust of 3 μm average size), 2000–4000 ppmv ammonia, 2000–2500 ppmv H2S, and 0.5–1.0% vaporized tars, oils, phenols, and other condensible hydrocarbons. The fuel gas was burned with air at 6–7 bar pressure and 400 °C temperature in a gas turbine combustion system at overall fuel-air ratios up to 0.25 (overall equivalence ratio 0.36). Gaseous emissions were sampled in the exhaust stream and measurements made for O2, CO2, CO, unburned hydrocarbons, NOx, and SOx. The CO and unburned hydrocarbon emissions were both below 20 ppmv at full firing conditions, indicating acceptable combustion efficiency. The NOx levels measured were up to 500 ppmv, and were due to the of conversion of fuel-bound nitrogen (ammonia principally). The SOx emissions directly followed the oxidation of fuel-bound sulfur (H2S principally). At part-load conditions, emissions of CO and unburned hydrocarbons were observed to increase, as expected. Stable operation was maintained down to a combustion system temperature rise of approximately 350 °C.
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Hewlett, S. G., A. Valera-Medina, D. G. Pugh, and P. J. Bowen. "Gas Turbine Co-Firing of Steelworks Ammonia With Coke Oven Gas or Methane: A Fundamental and Cycle Analysis." In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-91404.
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Abstract Following on from successful experimental trials employing ammonia/hydrogen blends in a model gas turbine combustor, with favorable NOx and unburned fuel emissions, a detailed numerical study has been undertaken to assess the viability of using steelworks by-product ammonia in gas turbines. Every metric ton (tonne) of steel manufactured using a blast furnace results in approximately 1.5 kg of by-product ammonia, usually present in a vapor form, from the cleansing of coke oven gas (COG). This study numerically investigates the potential to utilize this by-product for power generation. Ammonia combustion presents some major challenges, including poor reactivity and a propensity for excessive NOx emissions. Ammonia combustion has been shown to be greatly enhanced through the addition of support fuels, hydrogen and methane (both major components of COG). CHEMKIN-PRO is employed to demonstrate the optimal ratio of ammonia vapor, and alternatively anhydrous ammonia recovered from the vapor, to COG or methane at equivalence ratios between 1.0 and 1.4 under an elevated inlet temperature of 550K. Aspen Plus was used to design a Brayton-Rankine cycle with integrated recuperation, and overall cycle efficiencies were calculated for a range of favorable equivalence ratios, identified from the combustion models. The results have been used to specify a series of emissions experiments in a model gas turbine combustor.
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Narayanan, Guruprasath, and S. O. Bade Shrestha. "A Simulation Model of a Four-Stroke Spark Ignition Engine Fueled With Landfill Gases." In ASME 2007 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/icef2007-1618.
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A simulation model for establishment of performance parameters of a spark ignition engine fueled with landfill gas-methane and landfill gas-hydrogen mixtures is described. A two zone model was employed to estimate combustion duration, ignition lag, associated mass burning rates and performance parameters for various operating conditions in an internal combustion engine. The modeling consists of two main modules: a) a fuel-air and residual gas properties calculation, and b) equilibrium combustion product properties calculation with 13 species of equilibrium combustion products. The fuel-air and residual gas module calculates gas properties required in compression stroke and in an unburned zone of a combustion chamber. The equilibrium combustion products module calculates gas properties for the burned zone during combustion and expansion phases. In addition to engine parameters, combustion duration estimation methods were presented to accommodate the presence of high quantities of diluents such as carbon dioxide and nitrogen in methane to represent landfill gases, generally encountered in practice. Similarly, an effect of addition of hydrogen in landfill gas on performance of a spark ignition engine was also incorporated in the model. The pressure traces and other engine output parameters were modeled and compared with the experimental observations obtained in a variable compression single cylinder four-stroke spark ignition Co-operative fuel research (CFR) engine for different fuels that include methane, landfill gas and landfill gas–hydrogen mixtures and found satisfactory agreement. Matlab was used as the programming software in the model.
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Nithyanandan, Karthik, Chia-fon F. Lee, Han Wu, and Jiaxiang Zhang. "Performance and Emissions of Acetone-Butanol-Ethanol (ABE) and Gasoline Blends in a Port Fuel Injected Spark Ignition Engine." In ASME 2014 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icef2014-5644.
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Acetone-Butanol-Ethanol (ABE), an intermediate product in the ABE fermentation process for producing bio-butanol, is considered a promising alternative fuel because it not only preserves the advantages of oxygenated fuels which typically emit fewer pollutants, but also lowers the cost of fuel recovery for each individual component during fermentation. An experiment was conducted using a Ford single-cylinder spark-ignition (SI) research engine to investigate the potential of ABE as an SI engine fuel. Blends of pure gasoline and ABE, ranging from 0% to 80% vol. ABE, were created and the performance and emission characteristics were compared with pure gasoline as the baseline. Measurements of brake torque and exhaust gas temperature along with in-cylinder pressure traces were used to study the performance of the engine and measurements of emissions of unburned hydrocarbons, carbon monoxide, and nitrogen oxides were used to compare the fuels in terms of combustion byproducts. Experiments were performed at a constant engine speed and a comparison was made on the basis of similar power output (Brake Mean Effective Pressure (BMEP)). In-cylinder pressure data showed that the peak pressure of all the blends was slightly lower than that of gasoline, except for ABE80 which showed a slightly higher and advanced peak relative to gasoline. ABE showed an increase in brake specific fuel consumption (BSFC); while exhaust gas temperature and nitrogen oxide measurements show that ABE combusts at a lower peak temperature. The emissions of unburned hydrocarbons were higher compared to those of gasoline but the CO emissions were lower. Of particular interest is the combined effect of the higher laminar flame speed (LFS) and higher latent heat of vaporization of ABE fuels on the combustion process.
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Tanner, Matthew, Peter Stryker, and Indranil Brahma. "Assessment of the Feasibility of Biodiesel Blends for Small Commercial Engines." In ASME 2012 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icef2012-92159.
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Petroleum supply and environmental issues have increased interest in renewable low polluting alternative fuels. Published test results generally indicate decreased pollution with similar power output from internal combustion engines burning alternative fuels. More specifically, diesel engines burning biodiesel derived from plant oils and animal fats, not only reduce harmful exhaust emissions, but are renewable and environmentally friendly. A literature review found little previous research with biodiesel in small commercial diesel engines. This paper presents the research that was conducted to study the effect of biodiesel/diesel fuel blends on engine performance and emissions for a Yanmar L100 EE (7.1 kW) engine. This is a standard commercial grade diesel engine used for small equipment such as generators. Independent engine dynamometer and emissions testing were performed to validate the lower emission claims and assess the feasibility of alternative fuels. A testing apparatus capable of making relevant measurements was designed, built and used to perform this study. Fuel blends used included B2, B20, B40, B60, B80, and B100 where the biodiesel component of the blend was a commercial product. An analysis of the fuel showed large percentages of linoleic acid, palmitic acid and stearic acid which is typical for a blend of soybean oil and beef tallow. Test were performed at a constant torque (95 % of the continuously rated value) and variable engine speeds. Test results included calculated values of BMEP, BSFC, thermal efficiency, air mass flow rate, air fuel ratio, corrected NOx, energy lost to exhaust, and heat rejection, and measured values of unburned hydrocarbons, carbon monoxide, and carbon dioxide. Results indicate an increase in thermal efficiency compared to standard diesel and significant reductions of unburned hydrocarbons and carbon monoxide at all engine speeds. Brake specific fuel consumption increased with increasing percent biodiesel consistent with the decreased energy content of blended fuel. Significantly, there were small but consistent reductions in corrected NOx for all blends at all speeds. We posit possible explanations for these results, which are contrary to the published results for larger engines which show an increase in NOx for biodiesel blends.
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Hewlett, S. G., D. G. Pugh, A. Valera-Medina, A. Giles, J. Runyon, B. Goktepe, and P. J. Bowen. "Industrial Wastewater As an Enabler of Green Ammonia to Power via Gas Turbine Technology." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14581.
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Abstract This experimental study follows on from detailed Chemkin-Pro numerical analyses assessing the viability of by-product ammonia (NH3) utilization for power generation in gas turbines (GTs). This study looks specifically at NH3 in the industrial wastewaters of steelworks, resulting from the cleansing of coke oven gas (COG). The by-product NH3 is present in an aqueous blend of 60–70%vol water and is normally destroyed. An experimental campaign was conducted using a premixed swirl burner in a model GT combustor, previously employed in the successful combustion of NH3/hydrogen blends, with favorable NOx and unburned fuel emissions. This study experimentally investigates the combustion performance of combining anhydrous and aqueous by-product NH3 in an approximate 50:50%vol blend, comparing the performance with that of each ammonia source unblended. Green anhydrous NH3, a rapidly growing research topic, is a carbon-free energy vector for renewable hydrogen. Some potential benefits of combining the two sources are suggested. Ammonia combustion presents two major challenges, poor reactivity and a potential for excessive NOx emissions. Prior numerical analyses predicted that 15%vol addition of steelworks COG, at an inlet temperature of 550 K, may provide sufficient support for raising the reactivity of the NH3-based fuels, whilst limiting undesirable emissions. Therefore, addition of 10, 15 and 20%vol COG to each NH3-based fuel was investigated experimentally at 25 kW power with inlet temperatures > 500 K, at atmospheric pressure. As nitric oxide (NO) emissions decrease significantly with increasing fuel-to-air ratio, experiments were conducted at equivalence ratios (Φ) between 1.0 and 1.3, the precise range of Φ for each blend being optimized according to the modeling predictions for emissions. Leading blends, anhydrous NH3 with 15%vol COG and the 50:50%vol blend with 15%vol COG, achieved < 100 ppm and < 200 ppm NO respectively. Modest-sized steel plants produce ∼10 metric tons of by-product NH3/day. Aspen Plus was used to model a Brayton-Rankine cycle with integrated recuperation. Adopting typical losses (48% cycle efficiency) and ∼1.2 MPa combustor inlet pressure, the net electrical power generation of 15%vol COG blended with 10 tonnes/day of aqueous industrial NH3 and 25 tonnes/day of anhydrous NH3 (i.e. achieving a 50:50%vol blend) was ∼4.7 MW, ∼47% more power than for the same amount of anhydrous NH3 with 15%vol COG. This significant increase, indicates how industrial NH3 could enable green NH3 to power.
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Zornek, Timo, Thomas Mosbach, and Manfred Aigner. "Optical Measurements of a LCV-Combustor Operated in a Micro Gas Turbine With Various Fuel Compositions." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75481.
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In a recent joint research project, a new FLOX®-combustion system was developed to couple a fixed-bed gasifier with a micro gas turbine. Product gases from biomass gasification exhibit low calorific values and varying compositions of mainly H2, CO, CO2, N2 and CH4. Furthermore, combustion characteristics differ significantly compared to the commonly used natural gas. As the FLOX®-technology is considered as efficient and fuel-flexible featuring low emissions of hazardous pollutants, the design of the LCV-combustor is based on it. It contains a two-staged combustor consisting of a jet-stabilized main stage adapted from the FLOX®-concept combined with a swirl stabilized pilot stage. The combustor was operated in a Turbec T100 test rig using an optically accessible combustion chamber, which allowed OH*-chemiluminescence and OH-PLIF measurements for various fuel compositions. In particular, the hydrogen content in the synthetically mixed fuel gas was varied from 0 % to 30 %. The exhaust gas composition was additionally analysed regarding CO, NOx and unburned hydrocarbons. The results provide a comprehensive insight into the flame behaviour during turbine operation. Efficient combustion and stable operation of the micro gas turbine was observed for all fuel compositions, while the hydrogen showed a strong influence. It is remarkable, that with hydrogen contents higher than 9 % no OH radicals were detected within the inner recirculation zone, while they were increasingly entrained below hydrogen contents of 9 %. Without hydrogen, the inner recirculation zone was completely filled with OH radicals and the highest concentrations were detected there. Therefore, the results indicate a different flame behaviour with low and high hydrogen contents. Although the flame shape and position was affected, pollutant emissions remained consistent below 10 ppm based on 15% O2. Only in case of 0% hydrogen, CO-emissions increased to 43 ppm, which is still meeting the emission limits. Thus, the combustor allows operation with syngases having hydrogen contents from 0% to 30%.
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Diego-Marin, Antonio, Carlos Melendez-Cervantes, and Alejandro Mani-Gonzalez. "The Role of Atomizing Medium in the Effectiveness of Water-Oil Emulsions to Reduce Unburned Carbon Particles." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43583.
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Two older boilers were burning low grade heavy fuel oil (number 6) and emitting large amounts of unburned carbon particles. Owing to the short life remaining of the units and economic constrains, it was not possible to change to a better fuel or install new burners. To contribute to the solution of this problem, an experimental program was carried out by emulsifying water in the fuel oil. Tests were performed in a scale furnace (0.35MWth) and the emulsions that produced the best results were assessed in the two boilers, 28 and 34 MWe capacity with Y-jet atomizer type. The system to prepare the emulsion was very simple: water was added into the oil before the fuel oil pump, no chemical products were added and a static mixed was used to improve the water size distribution, which 90% ranged from 1 to 9 micron. In the pilot furnace the emulsions were prepared with 5 and 10% water and atomized with compressed air. Particle reductions of 43 and 67% were obtained compared with the net heavy fuel oil. In the boilers, the emulsions were prepared with the same amount of water, and were atomized with saturated steam. In the 28 MWe boiler, a similar particle reduction was obtained to that of the scale furnace. However, in the 34 MWe boiler there was no particle abatement. By using a commercial fluid dynamic computer code, it was found that the combustion air transferred heat to the steam raising its temperature. Thus, in the mixing chamber of the Y-jet atomizers, the steam was superheated and destroyed the water droplets of the emulsion. Compressed air and saturated steam as atomizing medium of the emulsions had similar effect on the unburned particle reduction. However, the effectiveness of the emulsions may be affected by the steam. Care should be taken to avoid the use of steam with a temperature higher than the saturated water temperature.
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Hamilton, Leonard J., and Jim S. Cowart. "Cold Engine Transient Fuel Control Experiments in a Port Fuel Injected CFR Engine." In ASME 2007 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/icef2007-1696.
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Air-fuel mixture preparation is particularly challenging during cold engine throttle transients due to poor fuel vaporization and transport delays in port fuel injected (PFI) engines. In this study, a PFI Cooperative Fuels Research engine is used to evaluate torque and measure in cylinder and exhaust CO, CO2 and unburned hydrocarbons during throttle transients at various early stages of engine warm-up. Fast flame ionization detectors and non-dispersive infra-red fast CO and CO2 detectors are used to provide detailed cycle-by-cycle analysis. Torque after cold throttle transients is found to be comparable to steady state torque due to allowable spark advance. However, cold transients produce up to 4 times the unburned hydrocarbons when compared to steady state operation. Finally, the x-tau fuel control model is evaluated in this challenging operating regime and is found to provide poor transient fuel control due to excessive fueling.
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Niki, Yoichi, Yoshifuru Nitta, Hidenori Sekiguchi, and Koichi Hirata. "Emission and Combustion Characteristics of Diesel Engine Fumigated With Ammonia." In ASME 2018 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icef2018-9634.
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It is well known that ammonia (NH3) combustion does not produce carbon dioxide (CO2) causing global warming. Therefore, NH3 has received much attention as an alternative diesel fuel for internal combustion engines. On the other hand, it has been reported that the exhaust gas of diesel engine fumigated with NH3 contains unburned NH3 with toxicity for humans and nitrous oxide (N2O) with strong global warming effect. Hence the NH3 and N2O emissions should be reduced to prevent the human health damage and global warming. The aim of this study was to develop the combustion strategies for reducing the unburned NH3 and N2O emissions on diesel engine fumigated with NH3. The experimental results indicated that the higher temperature combustion of NH3 prevents the N2O production and allows itself to react well. From the numerical simulation results, hydrocarbon combustion decomposes NH3 and N2O in ignition processes.