Highlights. Lignite predrying methods were compared in terms of their contribution to the plant thermal efficiency. The theoretical model for thermodynamic analysis of predried lignitefired power plant was established. The steam predrying has higher potential in plant thermal efficiency improvement than flue gas predrying. Main factors ...
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Microwave drying method decreases the coal moisture content from 52% to 10% [3]. Microwave . drying is a form of indirect heat ing because it uses electromagnet ic waves to gen erate heat in a n on
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Abstract. The overall objectives of this study are to develop an NMR method for measuring the water in coal, to measure the changes in coal structure that occur during coal drying, to determine what effect water has on retrograde/condensation reactions, and to determine the mechanism by which water may enhance coal reactivity toward liquefaction.
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Çicek developed a modified air table to beneficiate Turkish coal by a dry cleaning method and the separation results show that the coal samples having three size fraction of 85, 53 and 31 mm can be efficiently beneficiated by this modified air table with E values of, and, respectively, indicating a satisfactory ...
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The analysis presented here looks at the addon benefits of coal drying at the mine end relative to drying at plant sites, but is agnostic as to the particular coal drying technology employed. The issue is examined in the Indian context, but the findings are applicable elsewhere. It is well known that moisture is a major cause of thermal losses ...
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The overall process of the new coal drying equipment is shown in Fig. 1. This equipment is mainly composed of three parts, which are the heat transfer oil stove, the drying chamber and the waste heat utilization device. The heat transfer oil stove heats the heat transfer oil as a heat source to provide heat for the drying process, the coal ...
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An efficient dry coal cleaning method can offer a solution while avoiding problems associated with wet methods and generates partially dried coal. Air dense medium fluidized bed (ADMFB) can be an ...
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Alternate Drying Methods Dry the lignite using the "waste" heat from a light bulb. This method will model Coal Creek's use of waste heat from its boiler. Simply place the lignite in a sunny window and let it dry. Weigh the sample each day until the weight is constant for two days. No matter which drying method is used, have students ...
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The less accurate moisture estimation mentioned above for the dry coal samples with equal to or less than 12 wt.%H 2 O could be improved by the following advanced methods. (i) The use of the multiexponential model (Liu et al. Citation 2020 ) instead of the monoexponential model, Equation Eq.
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Accordingly, drying becomes largely a problem of heat transfer, and drying methods can be classified accordingly, namely: Radiant transfer. Transfer by surface contact and conduction. Transfer by hot gas contact. The mechanism of complete drying is really very complex—several phases are involved: The constant rate period.
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Agglomeration or briquetting. Coal preparation process starts with crushing and screening of freshly mined coal, which removes some of the noncoal material. Mechanical cleaning or "washing ...
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With the rising cost of energy and fuel oils, clean coal technologies will continue to play an important role during the transition to a clean energy future. Victorian brown coals have high oxygen and moisture contents and hence low calorific value. This paper presents an alternative non evaporative drying technology for high moisture brown coals based on osmotic dewatering. This involves ...
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Firstly, the current foodstuff drying methods are carefully performed in Puyi, Chahe, and Gusheng (Fig. 1, Fig. 2 and Fig. S1), such as burning mixed coal in open stove (MC + OS), lump coal in open stove (LC + OS), coal washing wastes in open stove (CWWs + OS), fuelwood in open stove, sundrying (Table S1) and honeycomb briquettes (HB) in IS.
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Microwave drying is an expensive drying method but its combination with conventional drying methods such as fluidized bed drying is a very promising and energy efficient technology, especially when applied at the falling rate period of coal drying when two thirds of the time may be spent on removing the last one third of the water (Fig. 1) [9].
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The lignite predrying process plays an important role in modern lignite power plants and the fluidized bed dryer with internal heat utilization is a promising drying method which has both high efficiency and costeffectiveness. After conducting an indepth analysis of a typical lignite predrying power plant, this work proposed a novel lignite predrying system with lowgrade heat integration ...
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This paper presents the results of research describing the thermokinetics of brown coal's (lignite) drying process in a fountainbubble fluidized bed dryer. The drying medium was atmospheric air of a variable temperature in subsequent tests, which ranged from 27 to 70 °C. This paper presents the results of many experimental studies for two different types of brown coal: xylite, from the ...
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However, dry coal preparation methods, which do not create the same disposal challenges as slurry waste, can be effective in areas where the water supply is restricted. Currently, most coal preparation plants recover fine coal only from the size fraction greater than 100 mesh (150 micrometer). Typically, this is done with wateronly cyclones ...
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Department of Energy Office of Scientific and Technical Information. Search terms: Advanced search options. ...
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Coal spontaneous combustion (CSC) is a complex physical and chemical process. Numerical simulation is an efficient method for visualizing and quantifying CSC. However, in previous models, the property parameters of coal are frequently assumed to be constant and hence cannot be used to predict accurately the thermodynamic behaviors during CSC. In this study, a fully coupled porous media model ...
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Coal drying. Coal preparation plants that employ fine coal cleaning by froth flotation can produce an unacceptable amount of moisture in the product. Thermal drying, in which the wet coal is dried in the hot gas generated by a coalor gasfired burner, is used in some plants to reduce the moisture content. Refuse and tailings management.
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mining methods which include some of the materials adjacent to the coal bed or thick partings of rock or clay within the coal bed. Mining methods also determine whether coal is supplied to a preparation plant wet or dry and in large lumps or small particles. Whereas surface mining and conventional underground
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