Characteristics of chars produced from lignites by pyrolysis at 808 °C following rapid heating

Nsakala, Nsakala ya; Essenhigh, Robert H.; Walker, P.L.

doi:10.1016/0016-2361(78)90189-8

Cited by 52 publications

(34 citation statements)

References 9 publications

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“…Note that the first pressure peak (or the shoulder for the Glen Harold Mine lignite) occurred at about Figure 15. Comparison of N 2 BET surface area correlation with experiment data from Fletcher and Hardesty 15 and Nsakala et al 18 The curve is the prediction, and the data points are the data. 10.5 ms, which corresponds to a total volatile yield of about 2% of the daf coal.…”

Section: Energy and Fuelsmentioning

confidence: 98%

Simulation of the Evolution of Pressure in a Lignite Particle during Pyrolysis

Yang

Fletcher

et al. 2014

Energy Fuels

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The evolution of pressure in a lignite particle during pyrolysis was simulated on the basis of the gas motion equation in porous media and considering the Klinkenberg effect. The chemical percolation devolatilization (CPD) model was used to describe pyrolysis. The pore diameter in the particle is close to the average free path of volatile gas molecules; therefore, the solid phase restrains the movement of gas. Because flow out of the particle is restricted, the internal pressure rises. The internal pressure first increases and then decreases during pyrolysis, and the evolution is influenced by heating conditions. The pressure rise is larger at a higher heating rate, but the duration of the pressure peak is shorter. The total pressure in the particle is larger at a higher ambient pressure, but the pressure difference between the inside and the surroundings decreases with the increasing ambient pressure. A growing internal pressure can restrain tar gasification, which can lead to the increase of the Metaplast content and the decline of the tar yield.

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Section: Energy and Fuelsmentioning

confidence: 98%

Simulation of the Evolution of Pressure in a Lignite Particle during Pyrolysis

Yang

Fletcher

et al. 2014

Energy Fuels

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“…It is generally accepted that the reactivity of coal chars in addition to coal origin, depends on accessibility of active sites in the char for reacting gases. For heterogenous systems, surface area or porosity, besides chemical factors, may play an important role in gasification reactivities [11][12][13][14][15][16][17][18][19][20]. The initial pore structure of char will, in general, be determined by the porosity of parent coal and pyrolysis conditions.…”

Section: Introductionmentioning

confidence: 99%

Physical and chemical properties of selected Turkish lignites and their pyrolysis and gasification rates determined by thermogravimetric analysis

Çakal

Yücel

Gürüz

2007

Journal of Analytical and Applied Pyrolysis

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“…The present study investigates the latter component of this interdependence. The diameters of lignite spheres were assumed to fit the Rosin-Rammler equation, applied frequently to describe size distribution in fragmented minerals [24,25]:…”

Section: Drying Of Various Coal Assortmentsmentioning

confidence: 99%

Numerical analysis of single and multiple particles of Belchatow lignite dried in superheated steam

et al. 2018

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Low production costs have contributed to the important role of lignite in the energy mixes of numerous countries worldwide. High moisture content, though, diminishes the applicability of lignite in power generation. Superheated steam drying is a prospective method of raising the calorific value of this fuel. This study describes the numerical model of superheated steam drying of lignite from the Belchatow mine in Poland in two aspects: single and multi-particle. The experimental investigation preceded the numerical analysis and provided the necessary data for the preparation and verification of the model. Spheres of 2.5 to 30 mm in diameter were exposed to the drying medium at the temperature range of 110 to 170°C. The drying kinetics were described in the form of moisture content, drying rate and temperature profile curves against time. Basic coal properties, such as density or specific heat, as well as the mechanisms of heat and mass transfer in the particular stages of the process laid the foundations for the model construction. The model illustrated the drying behavior of a single particle in the entire range of steam temperature as well as the sample diameter. Furthermore, the numerical analyses of coal batches containing particles of various sizes were conducted to reflect the operating conditions of the dryer. They were followed by deliberation on the calorific value improvement achieved by drying, in terms of coal ingredients, power plant efficiency and dryer input composition. The initial period of drying was found crucial for upgrading the quality of coal. The accuracy of the model is capable of further improvement regarding the process parameters.Keywords Superheated steam drying . Low-rank coal .

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Characteristics of chars produced from lignites by pyrolysis at 808 °C following rapid heating

Cited by 52 publications

References 9 publications

Simulation of the Evolution of Pressure in a Lignite Particle during Pyrolysis

Simulation of the Evolution of Pressure in a Lignite Particle during Pyrolysis

Physical and chemical properties of selected Turkish lignites and their pyrolysis and gasification rates determined by thermogravimetric analysis

Numerical analysis of single and multiple particles of Belchatow lignite dried in superheated steam

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