The coal used in this study was a lignite coal obtained from Hulunbeier in Inner Mongolia. Due to the high moisture content, the industrial drying process of the coal should be carried out prior to transportation and utilization. First, the exposed fresh coal sample was wrapped in plastic bags and immersed in water for storage.
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rising hot gases. In the flash dryer, coal is fed into a stream of hot gases for instantaneous drying. The dried coal and wet gases are both drawn up a drying column and into a cyclone for separation. In the multilouvered dryer, hot gases are passed through a falling curtain of coal, which is then raised by flights of a specially designed conveyor.
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The experimental results show that air drying, which reduces the free radical concentration of the coal, causes a decline in its oxygen reactivity whereas thermal dewatering, which causes an increase in the free radical concentration of the coal, enhances its oxygen reactivity.
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That method took the form of drying and pressing brown coal at the von der Heydt mine in Ammendorf, Germany, with a patent for a pipe dryer to dry brown coal first being registered in 1884. As an ...
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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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"A Comparative Study on Lignite Coal Drying by Different Methods"International journal of coal preparation and utilisation vol. ED40,july 2017 [2] SarkarAshis Kumar Adak, Joy Mukherjee, Abhijit " Studies on thermal upgrading of South Arcot lignite and its combustion behaviour" Fuel 17,,,
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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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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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The effective parameters are evaluated in three categories as follows: (1) the parameters about the drying media (the type of the media, the temperature, the pressure, the velocity and the relative humidity), (2) the coal parameters (the type of the coal and the size) and (3) the drying method. Keywords lowrank coal lignite drying
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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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Coal must also be dried for the following processes: (1) briquetting, (2) coking, (3) gasication, (4) lowtemperature carbonization, (5) liquid fuel synthesis, and others. The nal moisture...
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July 2021 Authors: Burcin Kaymakoglu Adana Alparslan Türkeş Science and Technology University Osman Sivrikaya Adana Alparslan Türkeş Science and Technology University References (12) Abstract and...
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ABSTRACT Abundance of lowrank coal (LRC) and increasing demand for energy provides motivation for upgrading LRC in terms of their high moisture content. Canadian lignite coal ( µm) was dried at different temperatures using different methods, namely hydrothermal treatment (HT), vacuum drying and hot air drying.
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The VNIIMT tested a coal drying method based on a solid heattransfer medium (for example, metal balls). This method considerably speeds up the drying process due to the large heattransfer area between the solid medium and the small particles. This reduces the length of the drum dryer to onehalf or even onethird of the original length and specific heat consumption.
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Heating the coal with toluene; Drying in a minimum freespace oven at 150 °C (302 °F) within a nitrogen atmosphere; Drying in air at 100 to 105 °C (212 to 221 °F) and relative loss of mass determined; Methods 1 and 2 are suitable with lowrank coals, but method 3 is only suitable for highrank coals as free air drying lowrank coals may ...
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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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Coal feeders provide coal to the coal pulverizers (mills) where the coal is pulverized and dried. Dryer coal is easier to pulverize, and less mill power is needed to achieve the same coal fineness. Additionally, with less fuel moisture, more complete drying of coal can be achieved in the mill.
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The chain reaction of active free radicals produced by the breakage of chemical bonds in coal release a large amount of heat [2831]. Studies on the variation of free radicals during coal oxidation on the basis of the mechanism of free radical chain reaction are of great significance for the exploration of CSC [3235], as free radical determination has become an effective means to reveal ...
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The interaction of certain substances can leave grease stains on the leather. The first thing to do is to apply a dry cloth to the stain to absorb as much liquid as possible. Next, you will need ...
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Depending on the coal drying method and the method of recovering heat from the vapours in the power plant system, an up to 5% increase in power unit efficiency can be achieved [61, 67, 78]. An additional effect of the higher power unit efficiency is a reduction in CO 2 emissions. The power unit efficiency can be further increased by adopting a ...
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This research offers a combination of experimental and artificial approaches to estimate the dilatancy point under different coal conditions and develop an early warning system. The effect of water content on dilatancy point was investigated under uniaxial loading in three distinct states of coal: dry, natural, and watersaturated. Results showed that the stiffnessstress curve of coal in ...
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Refined coal is the product of the coalupgrading technology that removes moisture and certain pollutants from lowerrank coals such as subbituminous and lignite (brown) coals, raising their calorific values. [1] Coal refining or upgrading technologies are typically precombustion treatments and processes that alter the characteristics of coal ...
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Few studies reported that the solar drying method can be chosen for drying the wet bagasse before feeding into the furnace for combustion (Phadkari et al., 2017, Subahana and Natarajan, 2016). Phadkari et al. (2017) developed an FCSD setup for solar drying of bagasse pulp where 1000 g of bagasse fibers were dried. The proposed dryer was useful ...
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Coal drying increases the thermal value of coal and makes it easier to transport. In this study, a coal drying system was designed using waste heat recovery systems, R134a refrigerant as working ...
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The exergy feeding and consumption rates for lignite dryers were compared in As shown in, the exergy feeding rate and exergy consumption rate for dryers vary greatly. The fluegas of 750 °C is used to dry lignite in the rotary dryer, so the exergy feeding rate is as big as kJ (kg H2O)1.
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