Grinding and combustion characteristics of woody
Three laboratory-scale mills are used to evaluate the suitable grinding method for woody biomass. Two types, namely ball and vertical roller mill, are employed in the actual boilers. ... Rate of combustion of size-graded fractions of char from a low rank coal between 1200 ... The best effect was when the biomass pellet mixing ratio was …
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Enhancement of flotation response of fine low-rank coal …
In view of the special surface properties of low-rank coal, many surface pretreatments methods have been proposed, such as grinding [5], ultrasonic [12], [13], microwave [14], [15], and heating approaches [16], [17], [18]. These methods can remove surface oxygen groups and improve the floatability. ... Low-rank coal samples were …
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Wetting thermodynamics of low rank coal and attachment …
The main pretreatment methods consist of preconditioning and grinding [23], [24], thermal [25] and microwave [26], ultrasound [27], direct contact mixing of the reagents with dry coal before wetting [28], which improve the hydrophobicity of low rank/oxidized coals by reducing the oxygenated functional groups on the coal surface thus making …
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Occurrence Characteristics of Fine-Grained Pyrite in Coal and …
The ore-grinding method can promote the separation of minerals and the coal matrix and is widely used to improve the flotation desulfurization efficiency. ... thiophenic compds. are more abundant in bituminous coal and anthracite than in low-rank coals. ... the first-order flotation kinetic model (ε = ε∞(1 - e-kt)) provided the best fit for ...
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Insight into the separation mechanism of coal macerals by …
Two kinds of coal samples, imported coal (IC) and native coal (NC), were used as the main raw material for this experiment. The proximate, ultimate analysis and vitrinite reflectance (R ¯ max) determination were carried out according to GB/T 211–2008, GB/T 31391–2015 and GB/T 6948–2008, respectively.As shown from the volatile matter …
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Processes | Free Full-Text | Improving Low Rank Coal …
The mixed collector can improve low rank coal flotation efficiency, but its synergistic mechanism needs to be further explored. In this paper, oleic acid-dodecane …
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Recent advances in beneficiation for low rank coals
Woodburn et al. [107] pointed out that the froth stability had a significant effect on the recovery of low rank coal and a more stability of froth was suitable for the beneficiation of low rank coal. Fuerstenau et al. [108] used non-ionic surfactants as collectors to float both oxidized and low rank coals, and found that both oxidized and low ...
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The ungrind and grinded effects on the pore geometry and …
However, a systematic framework has been designed on the hand-pick sampling method, low-pressure and temperature adsorption on N 2 and CO 2, and FESEM to develop a practical approach to understand the pore characteristics of the low-rank coal basin. For results reliability and comparison, six samples were selected from the low …
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Enhanced Flotation Separation of Low-Rank Coal with a …
The efficient flotation separation of low-rank coal is still a difficult problem. The development of a collector is the key to solve the problem. In this study, a kind of mixed collector scheme with a practical value is proposed. The effects of the single ...
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Effect of Comminution Methods on Low-Rank Coal …
The floatability of fine low-rank coal particles can be greatly influenced by their morphological characteristics, such as shape and surface roughness. In this study, the attachment efficiency and detachment amplitude of fine low-rank coal particles produced by various comminution methods onto/from the bubble surface were investigated using …
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Quantitative analysis of heat release during coal oxygen-lean …
It can be seen that the influence of the O 2 /CO 2 /N 2 atmosphere on the maximum heat release rate was restricted by the coal rank. The low-rank coal burned faster due to its low carbon content ...
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Effects of grinding time on morphology and collectorless flotation of
The low-rank coal samples used in this paper were relatively uniform without grinding treatment, so the influence of surface roughness changes on flotation can be ignored [34] [35][36]. ...
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Slurryability and flowability of coal water slurry
1. Introduction. In most parts of the world, the energy generation framework is significantly dependent upon fossil fuels. As per the World Energy Outlook (2019), around 64% of electricity was generated using fossil fuels.Coal alone contributes 38% to the total electricity generation (World Energy Outlook 2019, 2019, 2019).This figure rises to 53.3% …
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The optimization of low-rank coal grinding for …
This study analyzed various significant parameters of the low-rank coal (LRC) grinding process, which involves a hammer mill and prepares coal for the KBR transport …
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What are the types of coal? | U.S. Geological Survey
There are four major types (or "ranks") of coal. Rank refers to steps in a slow, natural process called "coalification," during which buried plant matter changes into an ever denser, drier, more carbon-rich, and harder material. The four ranks are: Anthracite: The highest rank of coal. It is a hard, brittle, and black lustrous coal, often referred to as hard coal, …
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Effect of coal particle size distribution, volume fraction and rank …
Even though samples with the same mean particle sizes have close volume fraction values, their viscosities differ considerably. While the Siberian coal with a mean particle size of 50 μm and a volume fraction of 0.74 has a viscosity of 732 mPa s, the low-rank coal from Istanbul–Agacli with a volume fraction of 0.65 has a viscosity of 907 mPa s.
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A short review of improvement in flotation of low rank/oxidized coals
Atesok and Celik [50] used the addition of pitch in dry grinding process of difficult-to-float coal to achieve a remarkable increase in the recovery from 22.1% to 89.9% and a decrease in the ash content from 11.8% to 10.1 % in Fig. 3.The better penetration and selective attachment of high molecular weight components of coal pitch onto the …
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Low Rank Coal
For low-rank coals, subbituminous and lignite, the HGI is found to depend on coal moisture, which decreases as grinding proceeds. 5.6.2.10 Friability. The breaking of coal into dust during handling, transporting, and pulverizing causes explosion hazards, control of which requires special sensors and control equipment.
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Effect of NaNO2 Reductant Pretreatment on Low-Rank Coal …
As the reserves of high-quality coal resources in China are decreasing, it is imperative to improve the processing and comprehensive utilization of low-rank coal. In this study, NaNO2 was used for the flotation pretreatment test of the low-rank coal obtained from Majialiang, and the mechanism was discussed by contact angle analysis, zeta …
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Demineralization of low grade coal – A review
Since bio-desulfurization takes a longer duration of about 1–2 weeks, so, further research is essential to reduce the incubation time. 4. Chemical beneficiation of coal. Due to low demineralization achieved by physical techniques to produce clean and ultra-clean coal (UCC), chemical processes are frequently considered.
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Effect of NaNO2 Reductant Pretreatment on Low-Rank Coal …
The results showed that when the dosage of NaNO 2 was 2000 g/t and the pretreatment time was 5 min, the flotation effect was the best, the ash contents of concentrate ash and tailings and the combustible recovery were 17.15, 37.12, and 42.23%, respectively; the combustible recovery increased by 12%.
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A new flotation scheme for a difficult-to-float coal using …
DOI: 10.1016/S0016-2361(00)00012-0 Corpus ID: 97888385; A new flotation scheme for a difficult-to-float coal using pitch additive in dry grinding @article{Ateok2000ANF, title={A new flotation scheme for a difficult-to-float coal using pitch additive in dry grinding}, author={G{"u}nd{"u}z Ateşok and M. S. Çelik}, journal={Fuel}, year={2000}, …
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Improvement of Low‐Rank Coal Flotation Based on the …
Abstract The main reason for low separation efficiency in low rank coal (LRC) flotation was the small wettability difference between organic matter and gangue. ... This method is that changing the adsorption liquid environment (adding Ca 2+) to enhance the selective adsorption of surfactants on the surface of organic matter and …
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Review on treatment technologies of coal gasification wastewater …
Coal with high activity, low geological age, fine grain size, low ash melting point, and low ash content. Wide adaptability, low-rank coal. Wide adaptability, inferior coal. Gasification temperature: Low: High: High: High: Characteristic of generated wastewater: Pollutant is complex and concentration is high; COD: 3000–5000 mg/L, NH 3 …
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Enhancing flotation performance of low rank coal by …
Section snippets Materials. The coal sample under 0.5 mm, a kind of non-caking coal, which is a low-coalification/low-rank bituminous coal, was provided by Meizhiyou coal preparation plant in Shanxi Province of China.The proximate and ultimate analyses of coal sample are shown in Table 1, where M ad is the moisture content, A ad …
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Enhancing flotation cleaning of intruded coal dry-ground …
Grinding dry low rank coal with collector not only increased the flotation recovery but also reduced the clean coal ash content (Ateşok and Celik, 2000). The hydrophilic surface of coal could be covered by the collectors and hence the floatability of ground coal was enhanced (Ahmed and Drzymala, 2012).
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Enhanced Flotation Separation of Low-Rank Coal …
The efficient flotation separation of low-rank coal is still a difficult problem. The development of a collector is the key to solve the problem. In this study, a kind of mixed collector scheme with a practical …
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Improved floatability of low-rank coal through surface …
Low-rank coal (LRC) contains a developed pore structure and rich oxygen-containing functional groups (OCFG). Therefore, it cannot easily be upgraded using flotation technology.In this study, simple and effective hydrothermal pretreatment (HP) was performed to reduce the porosity and increase the hydrophobicity of LRC surface. LRC …
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Experimental study on the effect of inherent moisture on hard coal …
The Yaojie No. 3 coal mine is located in the middle of the Yaojie coal field, Gansu. The gas (CH 4) content of the coal seams is small, while the contents of CO 2 and N 2 are larger, the relative emission quantity of CO 2 is 9.18–15.15 m 3 /t d. The No. 3 coal mine is considered to be a low gas, coal (rock) and carbon dioxide outburst mine.
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Studies of the relationship between mineral matter …
Minerals identified in raw coal samples by XRD include quartz, gypsum, calcite, aragonite, feldspar, jarosite, pyrite, goethite, kaolinite, illite, smectite, chlorite, and …
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