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Öğe 3.5 d temperature model of a coal stockpile(TAYLOR & FRANCIS INC, 2008) Ozdeniz, A. H.; Corumluoglu, O.; Kalayci, I.; Sensogut, C.Overproduced coal mines that are not sold should remain in coal stock sites. If these coal stockpiles remain at the stock yards over a certain period of time, a spontaneous combustion can be started. Coal stocks under combustion threat can cost too much economically to coal companies. Therefore, it is important to take some precautions for saving the stockpiles from the spontaneous combustion. In this research, a coal stock which was 5 m wide, 10 m long, and 3 m in height, with a weight of 120 tons, was monitored to observe internal temperature changes with respect to time under normal atmospheric conditions. Internal temperature measurements were obtained at 20 points distributed all over the two layers in the stockpile. Temperatures measured by a specially designed mechanism were then stored into a computer every 3 h for a period of 3 months. Afterward, this dataset was used to delineate 3.5 D temporal temperature distribution models for these two levels, and they were used to analyze and interpret what was seen in these models to derive some conclusions. It was openly seen, followed, and analyzed that internal temperature changes in the stockpile went up to 31 degrees C by 3.5 D models created for this research.Öğe Artificial Neural Network Modeling of the Spontaneous Combustion Occurring in the Industrial-scale Coal Stockpiles with 10-18 mm Coal Grain Sizes(TAYLOR & FRANCIS INC, 2009) Ozdeniz, A. H.; Yilmaz, N.Companies consuming large amounts of coal should work with coal stocks in order to not face problems due to production delays. The industrial-scale stockpiles formed for the aforementioned reasons cause environmental problems and economic losses for the companies. This study was performed in a coal stock area of a large company in Konya, which uses large amounts of coal in its manufacturing units. The coal stockpile with 5 m width, 10 m length, 3 m height, and having 120 tons of weight was formed in the coal stock area of the company. The inner temperature data of the stockpile was recorded by 17 temperature sensors placed inside the stockpile at certain points. In order to achieve this goal, the electrical signal conversion of temperatures sensed by 17 temperature sensors placed in certain points inside the coal stockpile, the transfer of these electrical signals into computer media by using analog-digital conversion unit after applying necessary filtration and upgrading processes, and the record of these information into a database in particular time intervals are provided. Additionally, the data relating to the air temperature, air humidity, atmospheric pressure, wind velocity, and wind direction that are the parameters affecting the coal stockpile were also recorded. Afterwards, these measurement values were used for training and testing of an artificial neural network model. Comparison of the experimental and artificial neural network results, accuracy rates of training and testing were found to be 99.5% and 99.17%, respectively. It is shown that possible coal stockpile behavior with this artificial neural network model is powerfully estimated.Öğe Decrease of calorific value and particle size in coal stockpiles(TAYLOR & FRANCIS INC, 2008) Sensogut, C.; Ozdeniz, A. H.During storage of excess amount of coal, they lose both their economical value and cause environmental problems. In this work, two industrial-sized stockpiles were constituted at a coal stockyard of Western Lignite Corporation (WLC) in Tuncbilek, Turkey. The size of the stockpiles, formed as triangle prisms, was about 10 m 5 m wide with a height of 3 m; each mass being approximately 120 tons of coal in total. Some of the parameters that were effective on the stockpiles were measured in a continuous manner during this experimental work. The calorific losses and the decreases that occurred in particle size due to atmospheric conditions were also examined and detailed as the result of this work.Öğe Investigation of Coal Stockpiles of Tuncbilek Thermal Power Plant with Respect to Time under Atmospheric Conditions(TAYLOR & FRANCIS INC, 2009) Ozdeniz, A. H.Thermal power plants have delayed the coal that they will use at stockpiles mandatorily. If these coal stockpiles remain at the stockyards over a certain period of time, a spontaneous combustion can be started itself. Coal stocks under combustion threat can cost too much economically to coal companies. Therefore, it is important to take some precautions for saving the stockpiles from the spontaneous combustion. In this research a coal stockpile at Tuncbilek Thermal Power Plant which was formed in 5 m wide, 10 m long, and 3 m height with a weight of 120 tons to observe internal temperature changes with respect to time under normal atmospheric conditions. Later, internal temperature measurements were obtained at 20 points distributed all over two layers in the stockpile. The parameters, such as air temperature, humidity, atmosphere pressure, wind speed and direction, which are effective on the stockpiles, were measured and used to obtain the graphs of stockpiles' internal temperature.Öğe Modeling of coal stockpiles using a finite elements method(TAYLOR & FRANCIS INC, 2008) Ozdeniz, A. H.; Sensogut, C.In the case of coal stockpiles finding suitable environmental conditions, spontaneous combustion phenomenon will be unavoidable. In this study, an industrial-sized stockpile having a shape of triangle prism was constituted in a coal stockyard of Western Lignite Corporation (WLC), Turkey. The parameters of time, humidity and temperature of air, atmospheric pressure, velocity and direction of wind values that are effective on coal stockpile were measured in a continuous manner. These experimental works were transferred into a computer media in order to obtain similar outcomes by carrying out 2-dimensional analysis of the stockpile with Finite Elements Method (FEM). The performed experimental studies and obtained results were then compared.Öğe Monitoring and ANN modeling of coal stockpile behavior under different atmospheric conditions(TAYLOR & FRANCIS INC, 2008) Ozdeniz, A. H.; Ozbay, Y.; Yilmaz, N.; Sensogut, C.In this study, an industrial-sized stockpile of 5 m width, 4 m height, and 10 m length was built in a coal stock area to investigate coal stockpile behavior under different atmospheric conditions. The effective parameters on the coal stockpile that were time, weather temperature, atmospheric pressure, air humidity, velocity, and direction of wind values were automatically measured by means of a computer-aided measurement system to obtain Artificial Neural Network (ANN) input data. The coal stockpiles, which should be continuously observed, are capable of spontaneous combustion and then causing serious economical losses due to the mentioned parameters. Afterwards, these measurement values were used for training and testing of the ANN model. Comparison of the experimental and ANN results, accuracy rates of training, and testing were found as 98.6% and 98.7%, respectively. It is shown that possible coal stockpile behavior with this ANN model is powerfully estimated.Öğe The Relationship Between the Natural Compaction and the Spontaneous Combustion of Industrial-scale Coal Stockpiles(TAYLOR & FRANCIS INC, 2011) Ozdeniz, A. H.; Corumluoglu, O.; Kalayci, I.The companies necessarily store their coal needs in their stock areas in which stock fires occur due to long stay periods of coals and cause serious damages in terms of the economy and environment. In this study, in order to determine the conditions by which spontaneous combustion occurs due to long stays of coals under natural weather conditions, an industrial-scale coal stockpile was formed with 10-18 mm coal grain sizes. Temperature measurements were recorded by using temperature sensors placed at certain locations inside the stockpile. At the same time, the effects of atmospheric conditions on the stockpile were investigated by continuously measuring the values of weather temperature, weather humidity, atmospheric pressure, wind velocity, and direction that are the factors affecting these stockpiles. Stockpiles tend to be faced with compaction due to the gravitational effect under long-term stays and the vibrations resulting from the huge machines working closer to the stockpiles. For the purpose of measuring the magnitude of the compaction, digital photographs were taken at certain periods and then processed photogrammetrically using terrestrial photogrammetry software. Afterward, the relationship between the calculated compaction rate and the spontaneous combustion was determined.Öğe Statistical Modeling of Spontaneous Coal Combustion Due to the Effect of the Sun's Rays(TAYLOR & FRANCIS INC, 2015) Ozdeniz, A. H.; Sivrikaya, O.; Kelebek, S.Spontaneous combustion occurs in stockpiles in coal managements and causes interruptions in production and economical and environmental problems. This work was performed on an industrial-scale stockpile formed with +18-mm clean coal. The temperature changes of the stockpile exposed to sun's rays were measured. Concurrently, the values of solar intensity, air temperature, air pressure, air humidity, wind speed, and wind direction affecting the stockpile were measured continuously. A statistical model to predict spontaneous combustion was developed by multi-nonlinear-regression analyses. The correlation coefficients were calculated around 0.95 levels. With this model, the effects of atmospheric conditions on spontaneous combustion of coal stockpiles can be predicted.Öğe A statistical study on thermogravimetry of some coals in Turkey(TAYLOR & FRANCIS INC, 2008) Sensogut, C.; Yildirim, O. S.; Cinar, I.; Ozdeniz, A. H.A number of physical features of coal can be determined as the function of temperature by the utilization of thermal treatment applied to coal itself. The most common techniques encountered in literature on this matter are differential thermal analysis, thermogravimetric analysis, and differential thermogravimetric analysis. In this article, the thermogravimetric behavior and physicochemical characteristics of some Turkish coals have been defined. Additionally, the relationship between these characteristics of the coal samples has also been given in a statistical manner.Öğe Temperature profiles of coal stockpiles(TAYLOR & FRANCIS INC, 2008) Sensogut, C.; Ozdeniz, A. H.; Gundogdu, I. B.Excess of produced coals should be kept in the stockyards of the collieries. The longer the duration time for these coals, the greater possibility for spontaneous combustion to take place. Spontaneously burnt coals result in economical and environmental problems. Therefore, taking the necessary precautions before an outburst of the spontaneous combustion phenomenon is too important in terms of its severe results. In this study, a stockpile having industrial dimensions was formed in coal stockyard. The effective parameters on the stockpiles of coal such as temperature and humidity of the weather, time, and atmospheric pressure values were measured. The interior temperature variations of these stockpiles caused by the atmospheric conditions were also measured. The interior temperature distribution maps of the stockpile together with maximum and minimum temperature values were expressed visually and numerically by the assistance of obtained data.
