Report on comparison among current industrial scale lignite drying technologies (A critical review of current technologies)

Νikolopoulos, Nikos; Violidakis, Ioannis; Karampinis, Emmanouil; Agraniotis, Michalis; Bergins, Christian; Grammelis, Panagiotis; Kakaras, E.

doi:10.1016/j.fuel.2015.03.065

Cited by 108 publications

(36 citation statements)

References 28 publications

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“…LRC is a promising resource because of its low mining cost, high 2 reactivity, high amount of volatiles and low levels of pollution-forming impurities, such as sulfur, nitrogen, and heavy metals. [1][2][3][4] However, LRC also has some challenges caused by its high moisture content (30% to 40%), including its high transportation cost, low energy efficiency and high CO 2 emissions for electricity generation. [5,6] Additionally, its self-ignition tendency introduces difficulties in handling and storage, and its low friability renders blending operations and pneumatic transportation less effective.…”

Section: Introductionmentioning

confidence: 99%

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Drying behaviors of low-rank coal under negative pressure: Kinetics and model

et al. 2016

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The drying behaviors of low-rank coal (LRC) under negative pressure were studied with a vacuum-drying oven under different pressures and temperatures. The results confirmed the feasibility of using the Page model to predict the drying behaviors of LRC under negative pressure. A new ideal radical ball model was proposed to further qualitatively analyze the influences of pressure and temperature on the drying behaviors. Reasoning based on the radical ball model combining the Kelvin formula, Fick's first law of diffusion, Knudsen's diffusion law and transition diffusion region suggests that a higher negative pressure and temperature leads to a higher maximum dehydration rate, that larger pressure and temperature gradients cause smaller critical moisture contents, and that decreases in the drying pressure and increases in the temperature increase the instantaneous removal rate of bound water.

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Section: Introductionmentioning

confidence: 99%

“…[7] Drying plays a key role in the overall coal utilization process, including pyrolysis, combustion, gasification and liquefaction. [1,3,8] Therefore, it is of great significance to obtain insights into the drying character of LRC and develop improved drying technologies.…”

Section: Introductionmentioning

confidence: 99%

Drying behaviors of low-rank coal under negative pressure: Kinetics and model

et al. 2016

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“…Nevertheless, the surface temperature of lignite can still be kept at a relatively low level. In reality, spontaneous combustion during microwave drying of lignite is one of the main difficulties hindering its industrial application . Evidently, the safety of microwave drying is very crucial for its large‐scale application.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Characteristics of Ignition during Microwave Drying of Lignite

et al. 2016

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The spontaneous combustion of lignite during microwave drying was evaluated with the focus on the effects of, for example, microwave power and output mode, the final temperature of the samples, and the oxygen content of the drying atmosphere on the moisture contents corresponding to the ignition (IMCs). This empirical study was performed using a laboratory‐scale microwave oven. The lowest IMCs and the optimal drying effect of lignite were achieved using a power level of 60 W g−1, final surface temperature of 85–90 °C, and a lower oxygen content; pulsed microwave radiation could significantly lower the risk of ignition by reducing the overall surface temperature. In addition, the ignition temperatures at different moisture contents were measured comparatively by using conventional and microwave heating methods. Fourier transform infrared analyses of the samples revealed that microwave drying can upgrade the coal rank without affecting the coal quality.

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“…8 In recent works, researchers have underpinned the importance of poor quality brown coal in the overall energy mix. 9,10 Pakistan has the world's largest lignite coal reserve comprising 175 billion tons spread over 9600 km 2 and having an electrical potential equivalent to 100 000 MW or 50 billion tonnes of oil equivalent. 11 This particular site was discovered by the Geological Survey of Pakistan in 1992; however, because of the lack of intensive investigation, the role of coal in the energy mix never gained significant importance in Pakistan.…”

Section: Introductionmentioning

confidence: 99%

“…12 The technological option of either directly using lignite as a fuel or its products as a substitute to oil or natural gas necessitates studies under various reaction atmospheres. [8][9][10]13 The important combustion parameters have been evaluated for the various reaction atmospheres (air, oxygen-enriched air, oxyfuel, and oxygen-enriched oxy-fuel), especially for lignite and lignite−biomass blends. 13−17 The combustion performance has been reported to significantly increase, especially for an O 2 concentration of <60%, 14 and burning profiles shifted to lower temperatures with elevated oxygen levels.…”

Section: Introductionmentioning

confidence: 99%

Reactivity Analysis of Pakistani Thar Lignite Reserves in Oxidizing Thermogravimetric Analysis Atmospheres

et al. 2015

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and orders of reaction under the aforementioned reaction atmospheres were calculated using the Friedman method (a differential 15 isoconversional approach) and the Ghetti method. In this work, the primary dominating factor on the rate of mass loss from 16 devolatilization was the higher heating rate (40°C/min), and the second factor was the higher oxygen concentration of 30%. 17Overlapping of devolatilization and char oxidation zones was also observed at higher oxygen concentrations of 30%. Increased 18 reactivity of the Pakistani lignite was observed at a heating rate of 40°C/min and high oxygen concentrations of 30%.

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Report on comparison among current industrial scale lignite drying technologies (A critical review of current technologies)

Cited by 108 publications

References 28 publications

Drying behaviors of low-rank coal under negative pressure: Kinetics and model

Drying behaviors of low-rank coal under negative pressure: Kinetics and model

Experimental Study on the Characteristics of Ignition during Microwave Drying of Lignite

Reactivity Analysis of Pakistani Thar Lignite Reserves in Oxidizing Thermogravimetric Analysis Atmospheres

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