A comparison of acid treatment in the dewatering of Chinese and Australian lignites by mechanical thermal expression at high temperatures

He, Qiang; Yeasmin, Hasina; Miao, Zhenyong; Wan, Keji; Huang, Shaomeng; Hoadley, Andrew; Qi, Ying; Chaffee, Alan L.

doi:10.1016/j.fuproc.2016.01.010

Cited by 11 publications

(4 citation statements)

References 45 publications

(67 reference statements)

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“…(6) The lignite particle is in local thermodynamic equilibrium. (7) The thermal resistance of liquid water in the SLP is ignored.…”

Section: Slp Drying Modelmentioning

confidence: 99%

“…As the largest storage and most widely used low-rank coal, lignite has become the energy mainstay of China, especially because of its abundance, easy availability, low exploitation difficulty, and high reactivity. − However, the high moisture content of lignite might act as a dominating barrier hampering its wide application. Specifically, the high moisture content might result in the reduction of thhe calorific value and combustion efficiency of lignite − and bring about higher costs and potential safety hazards during transportation and storage. − Moreover, the high moisture content might lead to an increase in CO 2 emissions, a delay in devolatilization during the pyrolysis process, and the degradation of the gas quality during the gasification process . Under such circumstances, it is imperative that some rational dewatering technologies for lignite be developed to improve the competitiveness of its further utilization.…”

Section: Introductionmentioning

confidence: 99%

“…Specifically, the high moisture content might result in the reduction of thhe calorific value and combustion efficiency of lignite 11−14 and bring about higher costs and potential safety hazards during transportation and storage. 15−18 Moreover, the high moisture content might lead to an increase in CO 2 emissions, 17 a delay in devolatilization during the pyrolysis process, 7 and the degradation of the gas quality during the gasification process. 8 Under such circumstances, it is imperative that some rational dewatering technologies for lignite be developed to improve the competitiveness of its further utilization.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Numerical Simulation and Experimental Research on Drying Behavior of a Single Lignite Particle (SLP) under High-Temperature Flue Gas

Zhang

et al. 2017

Energy Fuels

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The drying behavior of a single lignite particle (SLP) in high-temperature (600–900 °C) flue gas was investigated by experiment and numerical calculations. A self-designed horizontal fixed-bed reactor was employed for high-temperature drying experiments. Based on the drying curves obtained from these experiments, no constant-drying-rate stage was found, and the SLP drying process included stages with increasing and decreasing drying rates. To explore the drying process in depth, a mathematical model was developed in which the SLP was simplified into a simple spherical model. Based on the dry–wet zone theory, the heat- and mass-transfer equations were established to describe the drying process. The simulated results calculated using MATLAB agreed well with the experimental data. The model can predict SLP drying behaviors including the effects of the drying time, the surface and internal temperature distributions of the lignite particle, the migration of the evaporation interface inside the particle, and so on. The predicted results indicated that the migration velocity of the evaporation interface and the temperature were linearly dependent and that a temperature of 700 °C was the most suitable temperature for lignite drying. Furthermore, the drying time can be predicted using the model according to practical applications. Thus, the model can be used for the optimization of the drying process parameters and can offer guidance for the development of new drying technologies.

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“…(6) The lignite particle is in local thermodynamic equilibrium. (7) The thermal resistance of liquid water in the SLP is ignored.…”

Section: Slp Drying Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical Simulation and Experimental Research on Drying Behavior of a Single Lignite Particle (SLP) under High-Temperature Flue Gas

Zhang

et al. 2017

Energy Fuels

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“…Coal drying can be achieved through evaporative drying and nonevaporative drying methods . In our previous study, we tried to dewater different ranks of lignites under nonevaporative conditions and found that in mechanical thermal expression (MTE) tests the effect of expression temperature (200 and 240 °C) on moisture content reduction is evident for soft lignite (Loy Yang from Australia), , but it is only marginal for hard lignite (Shengli from northeast of China). The development of hydrothermal dewatering (HTD), , another popular evaporative dewatering method, can modify the surface characteristics effectively, but it is limited for its harsh experimental conditions and environmental issues in terms of wastewater.…”

Section: Introductionmentioning

confidence: 99%

Drying Kinetics of Soft and Hard Lignite and the Surface Characteristics of Products

Miao

Tian

et al. 2017

Energy Fuels

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Hard (Shengli, SL) and soft (Zhaotong, ZT) lignite by high temperature drying processes using hot gas were explored in this study. The results showed that the temperature played a significant role in the drying process. For SL-2 mm and ZT-2 mm, the drying rate at 300 °C was 4.4 times and 13.6 times that at 150 °C, respectively, which meant that the influence of temperature was more prominent for ZT and the effects of particle size could be reduced by higher temperature. Fifteen kinds of widely used drying kinetics models were fitted with 125 drying tests at 150–300 °C with different particle sizes of different lignite ranks. The residual moisture content prediction equation was constructed based on the logarithmic model, which was associated with temperature, initial moisture content, and drying time. The volatile matters, oxygen-containing functional groups, and contact angle were analyzed to show the surface characteristics of products. SL had small changes after drying, while the volatile matters of ZT decreased 5% and the carboxyl group was significantly reduced, the contact angle was increased, and close to or even greater than SL.

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Influence of critical moisture content in lignite dried by two methods on its physicochemical properties during oxidation at low temperature

Zhao

Song

et al. 2018

Fuel

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A comparison of acid treatment in the dewatering of Chinese and Australian lignites by mechanical thermal expression at high temperatures

Cited by 11 publications

References 45 publications

Numerical Simulation and Experimental Research on Drying Behavior of a Single Lignite Particle (SLP) under High-Temperature Flue Gas

Numerical Simulation and Experimental Research on Drying Behavior of a Single Lignite Particle (SLP) under High-Temperature Flue Gas

Drying Kinetics of Soft and Hard Lignite and the Surface Characteristics of Products

Influence of critical moisture content in lignite dried by two methods on its physicochemical properties during oxidation at low temperature

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