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 ...
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.
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.
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].
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.
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 ...
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 ...
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 ...
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 ...
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 ...
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.
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.
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...
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.
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 ...
Drying of materials is an important and essential mechanism during the production process in industries. Drying fruits and vegetables is an ancient method used for food preservation.
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
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 ...
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].
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
There are several methods for drying and dewatering low rank coals for upgrading. In the present study, the development of drying and dewatering technologies of low rank coals is examined, as well as their drying mechanisms and operating conditions. The influences of drying temperature, pressure and coal size are also described.
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 ...
"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,,,
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 ...
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 ...
In addition, the traditional preparation method is supercritical drying, which is complex and has safety issues. Here, we successfully prepare a SiO2Al2O3 aerogel utilizing coal gangue as a raw ...
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