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Summers, Matthew Dean. "The role of moisture in spontaneous combustion /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.
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Halliburton, Brendan William. "Investigation of spontaneous combustion phenomenology of bagasse and calcium hypochlorite." Phd thesis, Australia : Macquarie University, 2002. http://hdl.handle.net/1959.14/36863.
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Thesis (PhD)--Macquarie University, Division of Environmental and Life Sciences, Department of Chemistry, 2002.Bibliography: leaves 234-240.
Introduction, theoretical descriptions of spontaneous combustion phenomena and aims of this thesis -- Laboratory measurements of the self-heating phenomenology of bagasse -- Field experiments investigating the self-heating behaviour of large scale stockpiles of low symmetry -- Self-heating and thermal ignition of calcium hypochlorite -- Experimental methods and procedures used for the critical ambient temperature of HCH -- Results of critical ambient temperature measurements upon single containers of hydrated high strength HCH -- Experiments on the interaction of self-heating drums -- Conclusions.
The hazard of spontaneous combustion is a problem that confronts any industry that transports or stores a reactive material. Bagasse is a reactive material that presents an expensive spontaneous combustion hazard for the sugar industry since this material is the principal fuel used at sugar mills. Calcium Hypochlorite is another such material presenting a significant industrial spontaneous combustion hazard for the transport and insurance industry as it has been linked to a number of expensive maritime conflagrations. The investigation of fundamental self-heating phenomenon is critical for the understanding, control and prevention of spontaneous ignition with these materials. -- By way of isothermal calorimetry techniques and fundamental thermal ignition measurements, this study has provided improved understanding into the oxidative self-heating phenomenology of bagasse and thermal ignition phenomenology of calcium hypochlorite. Both substances have been shown to possess unusual and previously unknown self-heating behaviour at temperatures below 100°C, with water being a principal component of each mechanism. -- The outcomes of this study have provided a platform which has enabled current mathematical models to predict large scale self-heating phenomena for industrially stored quantities of these materials.
Mode of access: World Wide Web.
240 leaves, bound ill
3
Moqbel, Shadi. "CHARACTERIZING SPONTANEOUS FIRES IN LANDFILLS." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2695.
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Landfill fires are relatively common incidents that landfill operators encounter which have great impact on landfill structure and the environment. According to a U.S. Fire Administration report in 2001, an average of 8,300 landfill fires occurs each year in the United States, most of them in the spring and summer months. Subsurface spontaneous fires are considered the most dangerous and difficult to detect and extinguish among landfill fires. Few studies have been conducted on spontaneous fires in landfills. Information regarding the thermal behavior of solid waste is not available nor have measurements been made to evaluate spontaneous ignition of solid waste. The purpose of this research was to provide information concerning the initiation of spontaneous ignition incidents in landfills, and investigate the conditions favoring their occurrence. This study enabled better understanding of the self-heating process and spontaneous combustion in landfills. Effects of parameters critical to landfill operation on spontaneous combustion were determined. Spontaneous combustion occurs when materials are heated beyond the ignition temperature. Temperature rise occurs inside the landfill due to exothermic reactions which cause self-heating of the solid waste. Oxygen introduction leading to biological waste degradation and chemical oxidation is believed to be the main cause of rising solid waste temperatures to the point of ignition. A survey was distributed to landfill operators collecting information regarding spontaneous firs incidents in their landfills. Survey results raised new questions necessitating further study of subsurface fires incidents. Subsurface spontaneous fires were not restricted to any landfill geometry or type of waste (municipal, industrial, commercial, and construction and demolition). Results showed that landfill fires occur in landfills that do and do not recirculate leachate. Although new methods have been developed to detect subsurface fires, landfill operators depend primarily on visual observation of smoke or steam to detect the subsurface fires. Also, survey results indicated that excavating and covering with soil are the most widespread methods for extinguishing subsurface fires. Methane often has been suspected for initiating spontaneous subsurface firs in the landfill. However, combustible mixture of methane and oxygen requires very high temperature to ignite. In this study it was shown that spontaneous fires are initiated by solid materials with lower ignition points. Laboratory tests were conducted evaluating the effect of moisture content, oxygen concentration and leachate on spontaneous ignition of solid waste. A new procedure for testing spontaneous ignition is described based on the crossing-point method. The procedure was used to study the spontaneous combustion of solid waste and determine the auto-ignition temperature of the solid waste components and a synthesized solid waste. Correlations have been established between auto-ignition temperature, specific weight and energy content and between self-heating temperature and specific weight. Correlations indicated that compaction can help avoid spontaneous combustion in the landfill. Dense materials require higher energy to increase in temperature and limit the accessibility of oxygen. In the experimental work, moisture was found to promote both biological and chemical self-heating. Increasing moisture content lowers the solid waste permeability and absorbs more energy as it evaporates. Dissolved solids in leachate were found to promote self-heating and ignition more than distilled water. Varying oxygen concentrations indicated that heat generation occurs due to chemical oxidation even at oxygen concentration as low as 10% by volume. However, at 10% by volume oxygen, solid waste did not exhibit thermal runaway nor flammable combustion. At 0% by volume oxygen, tests results indicated occurrence of self-heating due to slow pyrolysis. A numerical one-dimensional energy model was created to simulate temperature rise in landfill for four different scenarios. Using the results from the laboratory experiment, the model estimated the heat generation in solid waste due to chemical reactions. Results from the scenario simulations indicated that moisture evaporation is the major heat sink in the landfill. The model showed that gas flow has a cooling effect due to increasing amount of evaporated water and can control the temperature inside the landfill. The model showed that a temperature higher than the biological limit can be maintained in the landfill without initiating spontaneous fire.Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engineering PhD
4
Rambha, Ravi Varma. "Prediction of the propensity of coal for spontaneous ignition in storage preparation and firing systems." Thesis, University of Nottingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289320.
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Sujanti, Wiwik. "Laboratory studies of spontaneous combustion of the Victorian brown coal /." Title page, summary and contents only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phs9478.pdf.
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Guo, Wendi. "Self-heating and spontaneous combustion of wood pellets during storage." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/43931.
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Self-heating of wood pellets is a major concern during long term storage. Internal temperatures rose to 57℃ in 10 days in a wood pellet silo of 21.9 m diameter in Fibreco Inc. (Vancouver, Canada) after pellets (about 20℃) were loaded into the silo. Self-heating could lead to serious accidental fires, causing enormous damage and danger to workers. In this study, the self-heating rate at different temperatures was experimentally determined, and the thermal properties were measured. for wood pellets produced in British Columbia, Canada. The factors such as moisture content, pellet age and environment temperature were investigated and their impacts on the self-heating process were analyzed.
Moisture content has a significant effect on effective thermal conductivity and specific heat capacity of packed pellets, but has no effect on the self-heating at the temperature range of 30℃ to 50℃. Pellets age and environment temperature are two major factors impacting the self-heating and off-gassing process. The self-heating rate is significantly increased at higher a temperature and eventually will lead to a thermal runaway when the ambient temperature is high enough. Experimental results show that the critical ambient temperature for thermal runaway decreases as the reactor size increases. The reaction kinetics was studied at both low temperatures (30℃ to 50℃) and high temperatures (100℃ to 200℃) and kinetic parameters were extracted from experimental results and correlations were developed.
Based on all measured properties data and kinetics data, a two-dimensional axi-symmetric self-heating model was developed to predict the self-heating process and thermal runaway in large wood pellet silo. The influences of cooling airflow rate, wall insulation, and dimension of the storage container, ambient temperature and wind condition were studied. The results show that air ventilation inside of the silo is a very effective approach for reducing self-heating and preventing thermal runaway at ambient temperatures lower than 330 K. The critical ambient temperature for a 21 m diameter silo can be as low as 36℃ in the absence of air ventilation. The current model can be used to safe guide the design and operation of large industrial wood pellets silos.
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Govender, Soobramoney. "A critical investigation into spontaneous combustion in coal storage bunkers." Diss., University of Pretoria, 2015. http://hdl.handle.net/2263/58065.
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In coal mining, spontaneous combustion can occur in many areas such as stockpiles, underground workings, waste dumps, coal faces, in-pit ramps and backfill areas. Spontaneous combustion has been defined as an oxidation reaction, which occurs without an external heat source. Although not limited to coal, the most significant hazard of spontaneous combustion is the fires that occur in coal mining operations around the world. These fires pose a serious risk to the safety of workers in the coal mines. This phenomenon also has an environmental impact, which can affect the quality of life for future generations.
Extensive research work has been done and recorded about spontaneous combustion in coal stockpiles, dumps and coal faces, but very limited work has been conducted on raw coal storage bunkers. This study investigated the occurrence of spontaneous combustion in coal storage bunkers, and established that there is no single document available that addresses the problem adequately. Therefore, a need was identified to create a guideline with decision analyser steps to be able to arrive quickly at a possible solution to the problem.
This work does not address spontaneous combustion in underground workings, waste dumps, stockpiles, coal faces, in-pit ramps and backfill areas.
It was found that important factors affecting the possibility of SC occurring were the type of coal being supplied to the bunker, the mining practice with regard to the standing time of the loose cubic metres of coal on the mining benches, and the impact of the physical factors around the bunker.
The information obtained could be of great significance when designing or trying to solve spontaneous combustion problems in raw coal storage bunkers. The guideline and decision analyser steps can be applied early in the phase of the project in order to minimise or eliminate similar mistakes made in the industry over the years.Dissertation (MSc)--University of Pretoria, 2015.
Exxaro
Mining Engineering
MSc
unrestricted
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Watt, Alan William. "The movement of gases in longwall coalface wastes liable to spontaneous combustion." Thesis, University of Nottingham, 1987. http://eprints.nottingham.ac.uk/11215/.
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The increasing depth, distance from surface connections and falling quality of coal mined are factors that increase the risk of spontaneous combustion in working areas. The trend towards high capital investment, high output faces significantly raises the economic consequences of spontaneous combustion. Much work has been directed towards methods of identifying the liability of a coal to spontaneously combust under given conditions. The cost of prevention and combat of spontaneous combustion underground is high, however this work is carried out with little knowledge of the likely location of a heating in a coalface waste. This thesis investigates the airflow patterns in a coalface waste, with a view towards improving the use of prevention and combat methods. The factors that affect the liability of a coal to spontaneously combust, and the methods of prevention and combat are discussed to provide a background to the subject area. An investigation into the flow of nitrogen that was injected from one hole into a coalface waste as a combat measure was conducted. The results of this showed how the amount of nitrogen entering the waste depended on the rise and fall of the atmospheric pressure. An attempt was made to develop a method of sampling gas from deep within the coalface waste. It proved impossible to sample further than 15m behind the face line. The results from this exercise are presented. The finite element method was used to model the pressure distribution in the waste under differing boundary pressure and waste permeability conditions. A suggested area at risk from spontaneous combustion is presented.
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Demirbilek, S. "The development of a spontaneous combustion risk classification system for coal seams." Thesis, University of Nottingham, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481567.
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Najarzadeh, Amir E. "EVALUATION AND PREVENTION OF SPONTANEOUS COMBUSTION DURING HANDLING AND STORAGE OF COAL." UKnowledge, 2018. https://uknowledge.uky.edu/mng_etds/39.
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Spontaneous combustion of coal has historically been a major problem for the coal industry, predominantly during storage and transportation. Various methods have been used in the laboratory for evaluating the propensity of different coal sources to self-heat. However, the heterogeneity of coal and the complexity of the system has resulted in inconsistencies and sometimes conflicting results as indicated by the findings reported in several publications.
The primary objective of the current study was to build a laboratory scale apparatus that simulates the condition of a coal stockpile to evaluate the events leading to spontaneous combustion and develop potential remedies. As such, the influential factors can be identified with confidence, thereby providing an improved understanding of the spontaneous combustion.
An adiabatic heating apparatus was designed and constructed which included instrumentation to closely monitor the oxidation process and the stages leading to spontaneous combustion under various conditions. The device was equipped with thermocouples which measured the temperature rise as a function of time leading to the determination of an index value that indicated the propensity of a given coal source to spontaneously combustion. The index was referred to as the R70 value which was measured as the temperature was increased during the period of rapid oxidation. The units for the index was degrees Celsius per hour. As such, a high index value reflected the likelihood of spontaneous combustion for a given coal source.
To standardize the test procedure, a detailed three-level statistical experimental design was conducted involving three critical parameters, i.e., particle size, oxygen flow rate and the duration of the drying period prior to feeding oxygen to the system. Using empirical models describing the R70 value as a function of the parameter values developed from the test data, it was determined that R70 was sensitive to the sample particle size and drying time. A decrease in particle size and drying time significantly increased the R70 value while the oxygen rate did not have a significant impact over the range of values tested. Based on the results of the test program, a standard test procedure was established to evaluate various coal sources and identify chemicals that could be used to remediate the spontaneous combustion issue.
Several sub-bituminous coal sources collected from the Powder River Basin were tested in the apparatus and found to be prone to spontaneous combustion as indicated by R70 values that approached 50oC per hour. Several chemicals were evaluated as a means of eliminating or slowing the spontaneous combustion process. These agents included anti-oxidants, binders and humectants. Organic binders were used to agglomerate the fine coal particles which limited surface area exposure. The effect significantly reduced the oxidation rate as indicated by a reduction in the R70 index from 44.07oC/hr to 5.71oC/hr. However, after entering the latent heat stage, the temperature increased rapidly at a rate of 27.58oC/hr. Humectants were evaluated which contained several hydrophilic groups, mainly hydroxyl groups, and thus have an affinity for water. As a result, when the coals were treated with humectant, the latent heat rate was reduced to 4.24oC/hr although the R70 remained relatively high. By using a combination of humectant and binder, the optimum result was obtained with an R70 value of 5.04oC/hr and a latent heat rate of 11.06oC/hr. These findings were successfully implemented into industrial practice for significantly delaying the spontaneous combustion event.
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Nevell, Roger Thomas. "Scaling the thermal stability test." Thesis, University of Portsmouth, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310467.
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Cooper, Malcolm. "The formation and monitoring of gases associated with the spontaneous combustion of coal." Thesis, Nottingham Trent University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280630.
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Ren, Ting Xiang. "A knowledge based system for the assessment of the spontaneous combustion of coal." Thesis, University of Nottingham, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334987.
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Banik, Janajiban. "Preventing spontaneous combustion in gob areas of retreating longwall panels by ventilating without bleeders." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/40307.
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Spontaneous combustion occurring in inaccessible areas of underground coal mines is
often intractable. Even though routine inspection and/or continuous monitoring help
detect the incubation of spontaneous heatings, they may not be able to identify the
locations with accuracy. Moreover, implementation of remedial measures is difficult. A
new approach to ventilation system design to overcome the problem is investigated in this dissertation. Ventilation layouts are analyzed to identify potential problem areas and nullify the probability of fire occurrence. The focus is directed to longwall gobs. The changing gob characteristics, especially the varying degree of consolidation at different parts of a gob as the face moves, is considered. Analytical studies and computer modeling show that bleederless ventilation in retreating panels is promising. The W -system of ventilation is most suitable. However, there may be difficulties in maintaining the middle entry in a WsystemPh. D.
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Eissa, A.-F. M. M. "Experimental investigation of spontaneous ignition of individual moving fuel/bipropellant droplets at different levels of chamber pressure." Thesis, Cranfield University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374143.
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Humphreys, D. R. "The application of numerical modelling to the assessment of the potential for, and the detection of, spontaneous combustion in underground coal mines /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18186.pdf.
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Morris, R. "Spontaneous combustion in coal mines and the interpretation of the state of a mine fire behind the stoppings." Thesis, University of Nottingham, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376641.
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Guichard, Florestan. "Mesures 1D mono-coups multi-espèces de température et de concentration par ajustement de spectres de diffusion Raman spontanée : application dans les flammes aérobies et les oxyflammes turbulentes." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR114/document.
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Les progrès technologiques des dispositifs expérimentaux ainsi que les récentes avancées pour la simulation des spectres Raman à haute température rendent aujourd’hui possible la mise en oeuvre d’une technique de mesures multi-espèces de température et de concentration uniquement fondée sur l’ajustement des spectres mono-coups de diffusion Raman spontanée collectés au sein des flammes turbulentes. Dans cette étude, cette stratégie de post-traitement, associée à une chaîne de mesure spécifique, est développée selon plusieurs axes pour permettre l’extension des mesures à des cas de flammes ordinairement hostiles aux mesures classiques Rayleigh/Raman résolues par inversion matricielle ou par méthode hybride. Dans une flamme diphasique d’éthanol, une thermométrie fondée sur l’ajustement des spectres de N2 a été mise en place afin de s’affranchir des contraintes liées à la diffusion de Mie des gouttes. L’intégration d’une thermométrie Raman à partir du spectre du méthane ainsi que d’une procédure de minimisation de l’émission de C2 dans le post-traitement des spectres ont permis la réalisation de cartographies multi-scalaires (température et toutes espèces majoritaires) dans toute la zone de recirculation d’une flamme turbulente légèrement fuligineuse générée par un brûleur bluff-body. Une thermométrie fondée sur la minimisation du spectre Raman de CO2 a également été développée et éprouvée au cours d’une campagne de mesures dans une installation d’échelle semi-industrielle reproduisant les conditions d’oxycombustion des cycles de turbines à gaz dans l’objectif de la capture et de la séquestration du CO2Recent progress in experimental devices and simulation of high-temperature Raman spectra enable the implementation of a spectral fitting method to solve single-shot Spontaneous Raman Scattering spectra collected in turbulent flames. In this study, this post-processing method, associated to a specific experimental set-up, has been developed to extend measurements to several cases of non-Raman friendly flames where matrix inversion or hybrid methods are usually limited. In a two-phase flame, N2 Raman thermometry has been used to overcome issues from Mie scattering of droplets. The implementation of a CH4 Raman thermometry and a minimization procedure of C2 emission in the data post-processing allowed the achievement of multi-scalar cartographies (temperature and all major species) throughout the recirculation zone of a slightly sooting turbulent flame stabilized on a bluff-body burner. A thermometry based on the minimization of CO2 Raman spectrum has also been developed and tested during a measurement campaign in a semi-industrial scale installation designed for the study of oxyfuel gas turbine cycle in the aim of carbon capture and sequestration
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REY, Sopheak. "Study on the SI-CI Combustion and the Spontaneous Ignition of Hydrogen Jets using a Rapid Compression/Expansion Machine." Kyoto University, 2010. http://hdl.handle.net/2433/126765.
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Ashman, James Mark. "An industry-led investigation for safe storage at full scale of compressed wood pellets including self-heating and spontaneous combustion." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/17303/.
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Large scale self-heating of wood pellets in storage is a major concern worldwide during long term storage due to the potential for fire with safety concerns for both personnel and plant. Additionally, any adverse publicity resulting from an incident involving biomass is likely to result in negative effects to the biomass industry as a whole. Self-heating could lead to serious accidental fires, causing enormous damage and danger to workers. The aim of the research in this thesis was to provide underpinning data and understanding in order to implement safe storage of wood pellets at Drax Power Ltd. Thus, the self-heating rates at different temperatures, and under different levels of inerting, were experimentally determined, and the thermal properties were measured for wood pellets produced for Drax Power Ltd. In addition, the thesis covers measurements at three scales; laboratory, temporary storage of approximately 40,000 tonnes through to largescale storage at approximately 280,000 tonnes spread equally over 4 domes… the largest storage of pellets ever investigated. The factors such as moisture content, pellet age and environment temperature were investigated and their impacts on the self-heating process were analysed. Moisture content has a significant effect on effective on self-heating but ventilation of the store was found to be more critical. Pellets age and environment temperature are two major factors impacting the self-heating and off-gassing process. The self-heating rate is significantly increased at higher a temperature and eventually will lead to a thermal runaway when the ambient temperature is high enough. Based on all measured properties, a self-heating model was developed to predict the self-heating process and thermal runaway in large wood pellet dome of ~120,000m3. This work contributed to the inerting of nitrogen gas to maintain an atmospheric (and therefore assumed within biomass) oxygen content less than 10% and monitoring protocols with the focus on carbon monoxide along with the understanding of temperature tracking for the large-scale dome storage of wood pellets, which is now used by Drax Power Ltd. Safety of all personnel working with biomass is paramount concern for Drax Power Ltd., which this thesis contributed to personal exposure monitoring and standard setting for gas exposure, mainly carbon monoxide and dioxide along with dust exposure. The handling of pellets through the supply chain and on site can cause the pellets to degrade and fine wood particles and dust is present within bulk pellets. Any release of wood dust into the atmosphere can pose a risk to health. Wood dust can cause serious health problems. Wood dust is a recognised respiratory irritant, sensitizer, asthmagen and for a limited number of species, a potential carcinogen (hard woods). Contact with wood dust can also lead to skin sensitisation and dermatitis. Drax Power Ltd, recognises it’s duties under Health and Safety and is committed to minimising the risk to health from wood dust in its premises. Both hardwood and softwoods dusts have a Workplace Exposure Limit (WEL) of 5mg/m3, which must not be exceeded. These are limits placed on the amount of dust in the air over an eight–hour shift. However the Control of Substance Hazardous to Health Regulations 2002 (as amended) requires exposure to wood dust to be “As low as reasonably practicable” (ALARP). Drax Power Ltd will manage exposure to wood dust to as low as reasonably practicable. The primary means of preventing exposure, is by containment of wood dust within the materials handling and processing plant. Dust control equipment such as Local Exhaust Equipment (LEV), will be used in conjunction with handling and processing plant to ensure that dust levels are kept to as low as is reasonably practicable. For certain operational and maintenance tasks it is necessary to use additional procedural controls to ensure that the risk of exposure to wood dust are managed effectively.
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Justeson, Jeremy Bradford. "Performance aspects in compositions for saxophone and tape David Heuser's Deep blue spiral, Paul Rudy's Geographic bells, and James Mobberley's Spontaneous combustion /." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3023553.
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Ajrouche, Hassan. "Thermographie et mesures de concentrations multi-espèces par diffusion Raman spontanée pour la combustion turbulente." Thesis, Rouen, INSA, 2016. http://www.theses.fr/2016ISAM0010/document.
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Les diagnostics lasers ont prouvé leur potentiel pour l'analyse des écoulements et des phénomènes de combustion par la mesure de champs de vitesses, de concentration d'espèces et de température. La diffusion Raman spontanée (DRS) est une des rares méthodes permettant de mesurer la température et la concentration de manière in-situ avec la possibilité de sonder plusieurs espèces simultanément. L'analyse des flammes turbulentes par DRS est difficile en raison de la nécessité de mesures mono-coup avec de fortes résolutions spatiales et temporelles et de la présence de lumière parasite. L'originalité de notre nouveau dispositif de mesure réside dans l'utilisation d'un obturateur électro-optique à base de cellule de Pockels (OCP), permettant d'éliminer les lumières non polarisées de fond de flamme, compatible avec une mesure 1D. Une réduction significative de l'émission de flamme et une amélioration du rapport signal sur bruit des espèces Raman actives ont été obtenues. La capacité de la DRS en tant que méthode de thermométrie mono-coup a été testée avec succès dans le cas d'une flamme de prémélange et de diffusion laminaire fuligineuse. L'écart relatif entre les températures moyennes mesurées dans les gaz brûlés et celles données par la modélisation de flamme est inférieur à 1 %. L'analyse de la thermométrie Raman à basse température a montré qu'une meilleure précision était obtenue avec la modélisation de 02 comparée à celle N2. Par la suite, le potentiel de la DRS à fournir des mesures simultanées de concentrations instantanées de N2, 02 et CO dans les flammes a été validé. Une évaluation des performances de différents détecteurs CCD accompagnés de l'OCP a également été réalisée. Les résultats obtenus avec la BI-CCD et la BI-EMCCD pour la température, le gradient de température et la forte densité sont en bon accord avec les calculs laminaires 1D de flamme adiabatique fournis par COSILAB. La BI-EMCCD a montré qu'elle est le détecteur le plus sensible pour la détection des espèces à faibles concentrations comme le CO. Enfin, des mesures par DRS ont été obtenues dans une flamme-jet de diffusion turbulente, en présence des suies illustrant le potentiel de cette technique pour construire une base de données importante pour la modélisation numérique des flammesLaser diagnostics have been proven to be an indispensable tool to analyze the flow and combustion phenomena by allowing non-intrusive measurements of the velocity field, concentration and temperature. Spontaneous Raman Scattering (SRS) is one of the few methods providing simultaneously in-situ temperature and multi-species concentrations. Measurement in turbulent flames by SRS is still challenging due to the emission background and the requirement of single-shot measurements with high spatial and temporal resolutions. The originality of the present approach consists in use of a large aperture Pockels cell based electro-optical shutter (PCS), that allows removing unpolarised background flame emission and compatible with a 1D measurement. A significant reduction of flame emission was observed and consequently signal to noise ratio was enhanced. The ability of SRS in terms of thermometric single-shot method was demonstrated successfully in premixed laminar flames and sooty laminar diffusion flames. The measured temperature in burnt gases and those calculated by adiabatic flame modelling was within 1 %. Thermometric Raman analysis for low temperatures demonstrates the reliability of measurements, with a better accuracy for 02 compared to N2. Subsequently, the ability of SRS technique to simultaneously measure instantaneous concentrations of N2, 02 and CO was demonstrated. The ability to measure single-shot scalar values accurately is assessed by comparing different CCD detectors with the PCS. The results obtained from the BI-CCD and the BI-EMCCD concerning temperature, temperature gradient and high density were in good agreement with the COSILAB calculation for 1D laminar adiabatic flame. The BI-EMCCD observed to be the most sensitive in detecting low concentration elements like CO. Finally, SRS technique was applied to a turbulent sooting jet flame, illustrating the potentiel of this technique to build an important database for flame modelling
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Taconnet, Solange. "Étude des réactions d'oxydation de l'isopentane et du néopentane en réacteur continu agité." Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL100N.
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Le présent travail est une contribution à l'étude de l'auto-inflammation des hydrocarbures, responsable du cliquetis dans les moteurs à allumage commande. Une comparaison des mécanismes d'oxydation du néopentane et de l'isopentane, élargie aux autres pentanes puis à certains alcanes doit permettre d'expliquer l'évolution des indices d'octane dans la famille des pentanes. L’étude expérimentale des réactions d'oxydation du néopentane et de l'isopentane est conduite en réacteur continu auto-agité par jets gazeux, à une température de 600°C et pour des temps de passage variant entre 0,37 et 1,18 seconde. Pour chacun des deux réactifs, un mécanisme radicalaire en chaines est écrit de façon systématique et permet de simuler les courbes de formation des produits de l'oxydation, grâce au logiciel CHEMKIN II. Le mécanisme est simplifié, puis les constantes de vitesse (estimées initialement par les méthodes de la cinétique thermochimique ou à l'aide de corrélations) sont optimisées pour adapter au mieux les resultats des simulations aux resultats expérimentaux. Il ressort de cette étude que les différences entre les mécanismes d'oxydation du néopentane et de l'isopentane à 600°C ne permettent pas d'expliquer de façon certaine la valeur relativement basse de l'indice d'octane du néopentane. Il semble que l'indice d'octane soit lié à la compétition entre l'effet inhibiteur de certains alcènes produits dans le mécanisme primaire et les réactions de branchements liées aux petits radicaux issus des processus de décomposition du réactif. Il est à ce jour impossible de relier de façon simple ces effets complexes à la structure des hydrocarbures
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Vincent, Stéphane. "Modélisation de l'allumage en milieu turbulent avec chimie complexe." Rouen, 1997. http://www.theses.fr/1997ROUES049.
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Ce travail concerne l'étude par simulation numérique de l'interaction qui existe entre les phénomènes turbulents et les phénomènes chimiques ayant lieu en combustion et en particulier durant les premiers instants de celle-ci. Le cas général est celui des gaz parfaitement prémélangés. Cette étude se fait par une approche basée sur les fonctions de densité de probabilité (PDF) couplée à des cinétiques chimiques complexes. Cette étude a été effectuée dans deux situations distinctes. Dans un premier temps l'étude est effectuée lorsque la combustion a lieu par auto-inflammation dans un mélange d'hydrogène et d'air a permis la mise en évidence, avec une méthode relativement simple à mettre en œuvre, des relations fortes entre les différentes espèces chimiques en cours de combustion. Ensuite cette étude a été effectuée dans le cas de l'allumage par étincelle de mélanges hydrogène-air et heptane-air en utilisant un modèle d'allumage ou l'étincelle est représentée par un dépôt d'énergie de durée finie et dans un volume fini. Le couplage de ce modèle d'allumage avec une cinétique chimique détaillée a permis la prédiction de limite d'inflammation. Le mémoire présente d'abord des rappels de la théorie de la combustion turbulente, différents types de modélisation et, en particulier, l'approche de la PDF. Puis une revue critique de modèles d'allumage par étincelle est effectuée et le modèle utilisé est présenté. Une description des méthodes de réductions des schémas numériques est proposée ainsi que le choix des cinétiques chimiques utilisées. Une étude de l'auto-allumage turbulent de mélange d'hydrogène-air est alors effectuée et dans la dernière partie l'étude de l'allumage turbulent par étincelle est effectué.
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Guionnet, Claude. "Les Combustions humaines spontanées." Lille 3 : ANRT, 1989. http://catalogue.bnf.fr/ark:/12148/cb37614147g.
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Aiteh, Hassan al. "Formation, structure et limites de detonation dans le bioxyde de chlore et dans l'azoture d'hydrogene." Paris 6, 1988. http://www.theses.fr/1988PA066624.
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Simiand, Nicole. "Contribution a l'etude cinetique des peroxydes organiques : decomposition en phase gazeuse et reactions de radical ro, formation dans un moteur cfr." Paris 6, 1987. http://www.theses.fr/1987PA066271.
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Eroglu, Huseyin Nehar. "Factors affecting the spontaneous combustion index." Thesis, 1992. http://hdl.handle.net/10539/22774.
Full textAbstract:
A thesis submitted to the Faculty of Engineering, University of the
Witwatersrand, Johannesburg, in
fulfillnent of the requirements for the degree of Doctor
of Philosophy, 1992The self-heating of coal is a problem which concerns the mining industry not only in South Africa, but also in many other countries. This thesis deals with the contouring of spontaneous combustion liabilities (WITS-ERAC index values) of different seams at the Durban Navigation Colliery and the relationship between the WITS-EHAC index values and the properties of the coal samples. In the determination of the spontaneous combustion liabilities 58 different coal samples were tested with an ignition-temperature test apparatus, crossing-point temperature tests and differential thermal analysis were conducted simultaneously. [Abbreviated abstract. Open document to view full version]
MT2017
29
Bradshaw, Steven Martin. "Modelling The Spontaneous Combustion Of Coal Beds." Thesis, 2015. http://hdl.handle.net/10539/16415.
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Moroeng, Ofentse Marvin. "Spontaneous Combustion of Coal : a South African Perspective." Diss., 2015. http://hdl.handle.net/2263/50712.
Full textAbstract:
Spontaneous combustion initiates as a result of low-temperature oxidation of organic
coal components. The upper limit of the temperature range cited for oxidation is 70°C and the
primary requirement is that combustion initiates without the use of external triggers.
Oxidation results in the formation of oxygenated hydrocarbon complexes, decomposition of
some of these complexes liberates a combination of heat and gaseous phases. In the instance
where spontaneous combustion is triggered, this heat is insufficiently dissipated into the
atmosphere such that the coal’s temperature surpasses the so-called ‘crossing point
temperature’. The nature of the gases evolved is dependent on coal’s overall composition, the
ability of oxygen to flow through the coal-body and the maximum temperature of the body.
CO2 production requires that oxygen is able to circulate throughout the coal-body whereas
CH4 production requires that parts of the body reach high temperatures simultaneous with
oxygen starvation.
Hydrocarbon complexes may be divided broadly into aromatic and aliphatic groups
corresponding to benzene and related compounds, and alkanes (and alkenes and alkynes)
respectively. The low-temperature oxidation of these two major groups is specific for the
nature of the hydrocarbon involved. Oxidation of benzene and similar compounds require
high temperature aqueous solutions as well as catalysation to progress. Conversely, aliphatic
compounds readily oxidize liberating heat energy ultimately responsible for self-heating.
Hydroxyls, carboxyls, carbonyls and inorganic carbonates thermally decompose at
temperatures above those commonly accepted for low-temperature oxidation and subsequent
spontaneous combustion. However, peroxides which are oxidation products of some ethers,
decompose within the appropriate low-temperature range.
Inertinite has been largely taken to be the main maceral group in South African
Coalfields and those of other Gondwana Provinces. However, this appears to be untrue for
the Waterberg Coalfield in general and several other seams in some of the other coalfields. It
is these vitrinite-dominated coals, that based on the knowledge of organic chemistry of
vitrinite appear to be most risk of spontaneous combustion. The Highveld Coalfield and the
No. 2 and 4 seams of the Witbank Coalfield as well as the Vryheid Formation in the
Waterberg atleast, are dominated by inertinite resulting in what has been interpreted to be
similar organic chemical makeup. On the other hand, vitrinite is the principal maceral group
of samples from the Waterberg specifically the Grootegeluk Formation and the No. 5 seam of the Witbank. This study concludes that the Grootegeluk Formation of the Waterberg, No. 5
seam of the Witbank as well as the Ermelo Coalfield are dominated by aliphatic
hydrocarbons and have an increased propensity towards to spontaneous combustion.Dissertation (MSc)--University of Pretoria, 2015.
tm2015
Geology
MSc
Unrestricted
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Brooks, Kevin Seth. "A simplified model for spontaneous combustion in coal stockpiles." Thesis, 2009. http://hdl.handle.net/10539/7424.
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Mthabela, Zamashinga Amanda. "Prediction of spontaneous combustion in coal by use of thermogravimetry." Thesis, 2016. http://hdl.handle.net/10539/22185.
Full textAbstract:
A research report submitted to the School of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, 2016.The self-heating of coals is a complex problem which has been occurring for centuries. This problem has been fatal to coal miners, an economical challenge to coal mines and a health risk in a release of greenhouse gases to the public in general. Therefore, everyone is affected by the self-heating of coal, which leads to spontaneous combustion when the ignition temperature is reached. There are many test methods that have been used to test spontaneous combustion in coal, but all have one common factor or disadvantage of requiring long periods of time before a conclusion can be deduced. This then creates a need for a rapid and reliable method to test the liability of coal to self-heat in the coal industry and thus the motivation for this project. The thermogravimetry analysis (TGA) method was selected to test the liability of coal to self-heat due to its short analytical duration. The Smith-Glasser oxidation test was selected to validate the TGA results obtained. The main aim of this project is to investigate the reliability of the TGA method to predict the propensity of coal to self-heat. 29 samples from different regions of South Africa were used, prepared to 250 μm for all the analyses and self-heating tests. All samples were analysed for proximate, calorific value, sulphur and petrographic properties before the spontaneous combustion liability tests began. The TGA method followed two tests: 1) the O2 adsorption and 2) the ignition test. Five different heating rates (3, 5, 7, 10, and 20) °C/min were run in order to obtain five derivative slopes which would be used to obtain the TGspc index. The oxygen adsorption test studies the mass increase at low temperature under exposure of air between the temperature ranges of 100 – 300°C. The Smith-Glasser oxidation test method studies the reaction of coal with O2 and calculates the O2 absorbed per amount of coal tested. The Smith-Glasser test results collaborated with most of the other analytical results, and with the TGA results to a certain extent. The TGA spontaneous combustion liability test requires additional analytical work to back up its results because the results do not appear as accurate as the Smith-Glasser oxidation test. It also requires repeatability tests to ensure the integrity of the results.
EM2017
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Raftopoulos, Ekaterini. "Multiplicity features of simple models for spontaneous combustion in coal stockpiles." Thesis, 2010. http://hdl.handle.net/10539/7529.
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Itay, M. "The low temperature oxidation of coal: its kinetics and implications for spontaneous combustion." Thesis, 2010. http://hdl.handle.net/10539/7474.
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Gemmell, Graham Barry. "Estimation of the propensity of remnant underground coal pillars to spontaneously combust during opencast mining at a colliery in the Witbank coalfield." Thesis, 2017. https://hdl.handle.net/10539/25542.
Full textAbstract:
A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering, 2016Spontaneous combustion of coal may occur when coal is mined, stored or transported and is influenced by a combination of intrinsic and /or extrinsic factors. While it is unusual for intact seams to burn in the highwall, the most common occurrence is when surface mines extract seams previously partially mined by underground bord and pillar operations. The aim of the study is to provide a predictive model (matrix) of the spontaneous combustion potential of remnant pillars at Colliery X. A number of different thermal, chemical and petrographic tests (coal factors) will be undertaken to determine their individual and collective impacts on the sponcom predictive model. The primary geology at the mine is conformable with that of the Witbank Coalfield. Battacharyya (1982) described 3 main factors in the spontaneous combustion of coal, mining factor, coal factor and geological factor which have an aggregate effect. Some of the main historical and present theories of sponcom are the pyrite theory, the bacterial theory, the oxidation theory and the humidity theory. It is important to note that no single factor is responsible for spontaneous combustion. The oxidation of coal occurs constantly. The temperature of the coal is a function of the rate of heat generation versus the rate of heat loss. Fires can start at outcrops and move through interconnected workings with heat transfer by conduction (into the overburden) or convection (between panels).The overburden can also insulate the burning coal seam. Geological factors such as depth of overburden, the degree of fracturing, and the nature of the overlying strata vary between coalfields. A coal seam fire or mine fire is the underground smouldering of a coal deposit, often in a coal mine. Such fires have economic, social and ecological impacts In order to extinguish a fire, one of three elements, fuel, oxygen, or energy, must be removed. The components of the fire triangle can be further subdivided into conventional mine control techniques and more or less unconventional or unproven mine fire control techniques. The thermal techniques discussed include the crossing point temperature, thermogravimetric analyses and oxygen absorption. Macerals, the microscopically identifiable organic constituents of coal, are one of the three basic parameters that define coal. The other two parameters are the coal rank and the mineral matter Vitrinite is the principal maceral group of the No.5 seam and inertinite dominates the No.2 and No.4 seams. The results obtained from the 22 drill-core samples and 2 ROM samples were matched to the existing borehole dataset (2296 boreholes) based on similarity of heat value (figure 3.11). A total of 24 test results (thermal, chemical and petrographic) from borehole A and borehole B were thus assigned to the borehole database which has approximately 1500 samples for each seam. By linking the laboratory datasets (borehole A and B) and the existing borehole database used for resource modelling, the sponcom variables could be modelled in a similar way to the coal resources. The overall risk matrix was calculated on a full seam basis by combining 15 variable scores, each variable having a score of 0, 1 or 2 (low-mod-high probability). The overall results from this research produced clear and unambiguous contour plans of different factors effecting sponcom of coal using single variable and combined variable datasets. In conclusion, it appears that the acceptability of a method for determining spontaneous heating characteristics of coal mainly depends upon how closely it predicts the spontaneous heating behaviour in the field conditions
CK2018
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Onifade, Moshood. "Spontaneous combustion liability of coals and coal-shales in the SOUTH AFRICAN coalfields." Thesis, 2018. https://hdl.handle.net/10539/26786.
Full textAbstract:
A thesis submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy,2018Spontaneous combustion is one of the major challenges in the South African coal mining sector. The event involves a range of complex physical and chemical processes, caused by the chemical reaction between coal, coal-shale and oxygen. Coal and coal-shale undergo low-temperature oxidation when exposed to oxygen in the air. The frequent occurrence of self-heating of coal-shale was reported in some South African coal mines to be the likely cause of spontaneous combustion but not the coal alone. Coal-shale found between layers (above and below) of coal seams vary considerably in intrinsic properties and proneness to spontaneous combustion. This thesis evaluates the main factors which most strongly affect the spontaneous combustion liability of coal and coal-shale. In South Africa, the widely accepted spontaneous combustion liability index, the Wits-Ehac Index was used to measure the spontaneous combustion liability index of fourteen (14) bituminous coal samples and 14 coal-shale samples respectively. The results of the Wits-Ehac Index show that most of the samples are liable to spontaneous combustion. However, the Wits-Ehac Index was unable to obtain a liability index during the testing of some coal-shale samples. This necessitated the development of a new device. A new apparatus which accurately measures the spontaneous combustion liability by using the reactivity of oxygen within coal and coal-shale was developed. A series of spontaneous combustion tests were conducted with this apparatus and a new liability index referred to as the Wits-CT Index was created. The Wits-CT Index uses the total carbon content and the temperature variations obtained from the samples during their reaction with oxygen to predict their spontaneous combustion liability. It was found that coal and coal-shale with a high Wits-CT Index are more liable to spontaneous combustion. The results from the two liability indices were compared with respect to what is happening in the mines and proved that samples with higher spontaneous combustion liability indices are more prone to spontaneous combustion than those with lower liability indices. The relationships between the spontaneous combustion liability (obtained from the Wits-Ehac Index and Wits-CT Index) and the geochemical data ((proximate and ultimate analysis, total sulphur and sulphur forms, petrographic composition, X-ray fluorescence (XRF) and X-ray diffractometer analysis (XRD)) of the samples were evaluated. The experimental results show that intrinsic properties of these materials complement the spontaneous combustion liability test results. Comparative analyses of the intrinsic properties and spontaneous combustion liability indicated similarities between the mechanism of coal oxidation and that of the oxidative processes undergone by coal-shale. It was found that the coal samples have higher intrinsic properties and spontaneous combustion liability than the coal-shale samples. This study indicates that the South African coal and coal-shale are enriched with more inertinite macerals than the vitrinite and liptinite macerals. The distribution of the macerals has been shown to have reasonable influences on spontaneous combustion liability. The contents of the main ash oxides are strongly related to the mineral constituents of the samples as indicated by the XRF. The quantity and mineral constituents in coal and coal-shale were evaluated by chemical procedures and optimised by the XRD analysis. The XRD analysis confirmed the presence of mineral constituents in the samples as identified by the XRF. The influence of the intrinsic properties of coal-shale in relation to coal properties affecting spontaneous combustion liability was established using a statistical method (regression analysis). The results provide quantitative descriptions and show the relationships between the dependence of the spontaneous combustion liability index (the Wits-Ehac Index and the Wits-CT Index) and independent variables (intrinsic properties). The linear regression analysis shows that the spontaneous combustion liability index indicates linear relationships with some of the intrinsic properties based on the set criterion and thus, identifies the major intrinsic factors affecting spontaneous combustion liability. It was found that a definite positive or negative correlation coefficient exists between the intrinsic factors and spontaneous combustion liability. A set of models to predict the spontaneous combustion liability was derived by using multiple regression analysis between the dependent variables and independent variables. The best significant correlation along with the most appropriate model as indicated by the R-squared values, the coefficient of correlations and standard error was used to predict the most reliable spontaneous combustion liability index. The results obtained from these models have been used as a reliable tool to support previous works on the role of intrinsic properties on spontaneous combustion liability. The application of chemical inhibitors on coal and coal-shale under laboratory studies were found to create an oxidative barrier on the surface of these materials to prevent self-heating and spontaneous combustion. The study indicated that by altering the self-heating characteristics (i.e. chemical and physical characteristics of a coal and coal-shale surface) through the use of chemical inhibitors, spontaneous combustion liability can be minimized.
XL2019
37
Wu, Tsang-Yi, and 吳昌益. "A study on the spontaneous combustion concern over the storage of Enviro-coal." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/61227711002657188577.
Full textAbstract:
碩士國立交通大學
工學院碩士在職專班產業安全與防災學程
93
While enjoying the advantages of having high reserves, low electricity production cost, high investment return, and much less nuclear-reactor-type of disputes, the use of coal fire nevertheless is tarnished by the fact that its burning release would cause serious contamination of the environment. The latter normally is required to be sized down via great size-up of all related post-processing facilities in order to comply with the environmental regulations. A new type of coal, enviro-coal (or, low-ash, low-sulfide-aerosol coal) has emerged and proved that, by using it instead, the as-released chimney outputs from normal boilers can already meet the environmental guidelines without having to incorporate further post-processing units. Therefore, in the global trend of increased public demand for a cleaner earth and subsequent much tighter environmental laws, adoption of the enviro-coal is seen to be a much better, likely inevitable alternative. However, the highly volatile, small-size particulate characteristics of the enviro-coal still is susceptible to oxidation and thus latent heat generation, which constitute great concern over the somewhat high risk of spontaneous ignition (or combustion) during its storage and transport. This thesis aims to study the internal temperature distribution and the tendency of spontaneous heat generation of a pile of enviro-coal (adaro, produced in Indonesia) situated in the open field of Tai-Power Taichung Thermal Power Plant. It is found that, via on-site measurements and coal content analyses, the surface water content of the enviro-coal and its surrounding wind speed are the two main factors deciding the rate of the internal heat generation and thus the subsequent temperature rising. It is hoped that the information disclosed by this current study may serve as an important safety reference to the coal field administration staff in general and in the end promote the wide-ranged use of the promising new alternative: enviro-coal.
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Sellassie, Kassahun G. "Study of heat production and transfer in shredded tires /." Diss., 2004. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3154570.
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Dlamini, Thabile Susan. "Analysis of trace gas emissions from spontaneous coal combustion at a South African colliery." Thesis, 2008. http://hdl.handle.net/10539/4747.
Full textAbstract:
Atmospheric pollution resulting from an open-cast coal mine situated 10 km southwest
of Witbank (Mpumalanga, South Africa) was investigated during summer and
winter 2004. Industrial and urban activities in and around Witbank release large
amounts of toxic and criteria pollutants into the atmosphere. Spontaneous combustion
from the many collieries in the Witbank area contributes to this problem. Direct,
automated, and continuous in situ measurements of trace gas concentrations and
prevailing meteorological parameters were carried out by a mobile monitoring unit
and an automatic weather station. The data collected show that spontaneous
combustion is a source of CO, NO, SO2 and H2S. Summer daily averages of SO2,
NO, NO2 and O3 concentrations ranged between 1 and 18 ppb, 0.3 and 40 ppb, 12 and
75 ppb and 0.9 and 19 ppb respectively. Winter daily concentrations of SO2 and O3
were much higher, ranging between 15 and 180 ppb and 14 and 30 ppb respectively.
NO and NO2, in contrast, were lower in winter (0.8 to 15 ppb and 2 to 28 ppb for
daily means). Winter daily average concentrations of H2S, CO and CO2 ranged
between 16 and 217 ppb, 2100 and 5100 ppb and 322 and 436 ppm). Synoptic
circulations over the Highveld were found to affect pollutant concentrations. During
winter, temperature inversions played a significant role in increasing the pollutant
concentrations in the early morning hours until about 10:00. Although considerable
amounts of NO, NO2 and O3 were captured; their concentrations were within the
South African Department of Environmental Affairs and Tourism’s permissible
levels as contained in the National Environmental Management: Air Quality Act
(2004). SO2 concentrations during winter 2004 exceeded the allowed standards.
Elevated concentrations of pollutants were mostly observed when the wind blew from
the SE, SSE, S and WSW directions, implicating the 2A south pits of the open-cast
mine investigated as the major source of the emissions.
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JHAN, PEI-JIE, and 詹霈潔. "Study of Spontaneous Combustion of the Heat Insulating Materials in Crude Oil Piping System." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/yy86wq.
Full textAbstract:
碩士國立勤益科技大學
化工與材料工程系
107
Crude oil pipeline conveying system is often operated at high temperature in petrochemical industrial plant. When the heat preservation material that coated pipeline system was absorbed the high-temperature crude oil, willed cause spontaneous combustion probability. In this paper, the case of spontaneous combustion was real in a special situation. We were collected samples of fire debris and combustible materials in the field, and the samples experimented with Gas Chromatography-mass Spectrometry, Fire testing of Spontaneous Combustion for Crude Oil, and Thermal Analysis Experiments etc. This study found after heat preservation material was absorbed crude oil, there will be an exothermic reaction of 247.39 J/g and about 30% of the heat losses when the temperature had been up to 170.03℃. The currently widely used space bag, when the heating temperature reaches about 203.64 ℃, there will be an exothermic reaction of 98.60 J / g, if up to about 399.32 ℃, the exothermic reaction of 117.74 J / g, there are about 95% of the heat losses. After the aforementioned series of tests, then reorganized the clues information, gradually confirm the cause of the fire in this case. Expect to pass the research results of this paper, as a precaution against spontaneous combustion of insulating materials, fire investigators or related research work can be provided, to determine the factors of spontaneous combustion of the reference information.
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Ulzama, Shabi [Verfasser]. "A theoretical analysis of single coal particle behavior during spontaneous devolatilization and combustion / von: Shabi Ulzama." 2007. http://d-nb.info/986096636/34.
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PETRÁK, Martin. "Zvláštní případy hoření osob." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-253477.
Full textAbstract:
In the Czech Republic, as well as in other countries, there are cases of fires reported, where the thermal destruction of the body of the victim is not a result of thermal effects of a fire of the surrounding space. These fires are typical for the affected area that is limited to the body and the immediate surroundings only. Frequently the bodies show extensive and complete thermal destruction of tissues to high levels of carbonization. Human tissue combustion appears in foreign sources, especially popular science, described with the term "Spontaneous Human Combustion". In the Czech Republic the translation equivalent is "samovolné vzplanutí osob". The motivation for the choice of the topic "Special Cases of Human Combustion" was the lack of adequate fire origin investigation methodology to be used by the members of the Fire and Rescue Service of CR. The other reason for the choice of the topic was the misleading information published in popular science sources and alternative information sources. The first step of the research was the literature research of the available professional texts and specific fire reports. Based on information gathered was designed scope and conditions of a research experiment conducted on samples of the same type of animal tissue, which corresponds to the human tissue. For the samples the tissue of a domestic pig was used and the samples were prepared to contain uniform percentages of muscle, fat and bone, including skin. The experiment was carried out in an accredited laboratory owned by the company PAVÚS, a.s. - fire testing laboratory #1026 in Veselí nad Lužnicí. With each sample the influence of different flammable substances on the level of subsequent damage of the animal tissue was tested. The influence of typical layered clothing, flammable base and cover was evaluated. Different real environment conditions were simulated with each sample. The aim of the thesis was an evaluation of the possibility of a start and the process of combustion of animal tissue. It was confirmed that the combustion of animal tissue, including bone tissue, is possible in a regular fire. The flammable materials in the form of clothing and the presence and the characteristics of a flammable base are crucial for the start and process of the combustion. The experiment revealed the possibility of further independent combustion of the tissue when supplied with a certain amount of initial energy by burning of the surrounding materials. The combustion of animal tissue characterically takes predominantly the form of smouldering lasting several hours, where the maximal measured temperature of the surface of the sample was 644,50 oC. The experiment further revealed the temperatures of the human tissue combustion not to be high enough to cause an ignition of flammable materials within defined distance. The results of the thesis can be used to define the basic guidelines for the members of Fire and Rescue Service of CR and the criminal justice, who can provide support with investigation of the causes of these types of fires of persons.
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Flint, John Derek. "Mine gas and coal dust explosions and methane outbursts - their causes and prevention." Thesis, 1990. https://hdl.handle.net/10539/24640.
Full textAbstract:
A Dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, for the degree of Master of Science in Engineering.Ignitions of methane and coal dust have caused considerable loss of life and damage to installations in South African collieries during the past century. The phenomenon of methane outbursts have also resulted in the creation of dangerous conditions underground. The dissertation examines the causes of methane outbursts and the seven main ignition sources leading to methane and coal dust explosions. These ignition sources were derived from an examination of Mines Department inquiries extending back to 1891. the date of the first known ignition of mine gas. Selected incidents were chosen from the official Inquiries for each ignition source and these are dealt with in detail. This includes an investigation into the many factors which developed prior to the individual explosions and the effects of the aftermath such incidents. Precautions to be adopted to prevent methane outbursts and minimise the risk of methane and coal dust explosions as a result of the seven ignition sources are detailed at the end of each chapter.
Andrew Chakane 2018
44
Thiele, Olaf. "Faseroptische Gemischbildungsanalyse in Otto-Motoren bei direkteinspritzenden Brennverfahren." Doctoral thesis, 2004. http://hdl.handle.net/11858/00-1735-0000-0006-B441-3.
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