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 ...
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 ...
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
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.
article{osti_, title = {Use of solidstate NMR techniques for the analysis of water in coal and the effect of different coal drying techniques on the structure and reactivity of coal. Quarterly report, December 1, 1991February 29, 1992}, author = {Netzel, D A}, abstractNote = {The overall objectives of this study are to develop an NMR method for measuring the water in coal, to ...
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.
Abstract. Western Research Institute has conducted a study of different methods of coal drying as pretreatment steps before liquefaction. The objectives of this study were to develop a combined chemical dehydration/nuclear magnetic resonance (NMR) method for measuring the moisture content of coal, to measure the changes in coal structure that occur during drying, and to determine the effects ...
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 ...
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 ...
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 Drying of low rank coal is a very significant topic due to its high economic value. One of the most important parameter in the designing of a dryer is the exiting moisture content of the material at the specified conditions and time. Aim of this study was to utilize the design of experiment methodology to determine the most effective parameters on the moisture content of the dried coal.
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...
Dry coal cleaning has claimed an important place in the current coal processing technology. The most important and reliable plants include rotary breakers, air jigs, FGX separators, air densemedium fluidised bed separators, radiometric sorters and others. ... The methods of manufacturing and materials of construction have also undergone changes.
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 ...
Highlights Biofilm formation on coal is of fundamental and applied interest in microbiology. We show that HMDS is a suitable drying agent for SEM imaging of biofilms on coal. Alternative methods ( critical point drying) are not suitable for coal samples. HMDS drying successfully generated SEM images in which cell morphology was intact.
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 ...
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.
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.
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 ...
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 ...
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.
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.
Modelling and calculation methods Description of the coal drying process The configuration of the coal drying system is schematically shown in Figure 1. The coal drying system consists of two major components, drying reactor (DRYREAC) and gassolid separation unit (SEP). The wet coal with 25 wt% of initial moisture (1) is heated by the hot ...
Regarding the liquefaction of coal, there does not appear to have been any systematic study of the methods of coal drying on coal structure and the role water plays in enhancing or lessening coal reactivity toward liquefaction. To conduct this study two coals, the North Dakota Beulah Zap lignite and the Utah Blind Canyon coals were chosen. ...
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 ...
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 ...
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.
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 ...
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.
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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