Introduction Increasing world populations and resulting economic issues have led to drastic increases in the demand for energy. Fossil fuels such as coal, oil and natural gas have thus far been the principal commodities up to about 85% in meeting the world's commercial energy needs [1], [2].
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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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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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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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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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Also sludge drying was enhanced for some preconditioning facilities using biomasses and pulverized coal (Zhao et al. Citation 2019). ... In the future, heat drying techniques are expected to be the leading methods for the drying of municipal or industrial sludge. As an advanced deep dehydration technique, heat drying has been used worldwide.
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These systems require heat input to dry asdelivered coal to certain specifications. Produced steam is typically used for this purpose, but since the Allam Cycle is based on use of sCO 2, and not steam, it is preferable to utilize alternative methods for coal drying.
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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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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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After t hermal drying methods, distillation methods are the next most commonl y used [9]. In these procedures, coal is heated in a liquid that has a bo iling point higher than that of water and is ...
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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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The drying rate curve of the thinlayer drying ex periment of 2 cm thick coal under different heat source temperature is shown in Figure 7. The abscissa in t he figure is the moisture content of coal,
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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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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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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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The repression of oxidation processes during drying should occur in the case of methods #1, #2 and #3, whereas possible oxidation of coal is expected in procedures #4 and #5. The medium vacuum used during experiments #1 and #3 was provided by an oil pump. For the drying experiments, about 2 g of coal were used. The effort was to obtain a dry ...
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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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Various drying procedures were applied to North Bohemian lowrank coal. Dried samples were subjected to CO 2 sorption analysis. Adsorption data were evaluated according to the DubininRadushkevich and Medek equation to describe the micropore parameters. It was proven that drying conditions may have an impact on the monitored characteristics of the studied coal, particularly on the surface ...
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A coal drying system was modelled and the calculation methodology was developed to calculate the system. Then the system performance was obtained and the exergy destruction and loss in the system ...
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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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Drying of three types of coals (Witbank coal, Taiheiyo coal, and Brau coal) was carried out by using supercritical carbon dioxide at K and MPa. Further, other adsorbent samples (wet zeolite and wet activated carbon) were adopted for comparison. Experimental results show that it is very difficult to extract water from wet zeolite but easy to extract water from wet activated carbon ...
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Lower upward air flow rates and smaller dustcollecting equipment with minimum possible moving parts and the possibility of using waste heat (lowquality heat) for simultaneous coal drying are some of the advantages of the ADMFB separators over the other dry methods [,, ]. Most of studies related to gravity separation in coal cleaning are from ...
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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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The following is a breakdown of the drying of each major fraction before the change: The plus ¼" material was being dewatered by use of vibrating screens to a moisture of 4. 2%, The ¼" x 28 mesh material was being mechanically dried in centrifuges to a moisture of % and then thermal dried.
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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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This assessment can be further used to determine usefulness of precombustion coal drying methods like integrated drying and partial coal gasification method, particularly for coal processed through dry or wet coal washing to improve the heat value with the exhaust flue gas immediate upstream of stack. Keywords: drying, moisture, ash ...
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Drying fruits and vegetables is an ancient method used for food preservation. Apart from the agricultural sector, there are many industries such as automobile, rubber, paper and pulp, sugarcane, wastewater treatment, lignite/coal, etc. require heat energy for drying during production processes. Conventional energy sources such as coal, natural ...
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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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Various drying methods have been discussed so far which are essentially used for coal drying. A major objective for LRC upgrade and optimization is to minimize the overall energy consumption in LRC drying, while making the drying process cost effective. It should be noted that each drying method can still be further . Conclusions
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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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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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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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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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A material supplier from Belgium would like to produce limestone powder for his custome...
India is rich in various mineral resources and it is an important mineral processing market
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