Water sorption on coals

Charrière, Delphine; Behra, Philippe

doi:10.1016/j.jcis.2009.11.064

Cited by 237 publications

(169 citation statements)

References 31 publications

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“…As reported by Shigehisa et al 6) and Charrière et al 15) , adsorption process includes three steps. (1) Adsorption on active adsorption sites; (2) formation of water clusters; and (3) pore lling of water clusters and capillary condensation in narrow pores.…”

Section: Introductionmentioning

confidence: 89%

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Effect of Hydrothermal Treatment Coupled with Mechanical Compression on Equilibrium Water Content of Loy Yang Lignite and Mechanism

et al. 2016

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Measurements of equilibrium water contents (EWCs) in samples obtained from hydrothermal treatment (HT) and HT coupled with mechanical compression (HT-MC) were undertaken across a range of relative humidities (RHs) to investigate the performance of EWC and its mechanism. The changes in the concentrations of carboxyl groups and mesopore volume were measured by an improved barium ion exchange and N 2 adsorption-desorption isotherms methods, respectively. The results showed that EWCs decreased with progressively severe HT and HT-MC conditions and EWCs of HT-MC samples were lower than those of HT samples, indicating that HT and HT-MC can upgrade lignite by reducing water loading capacity and HT-MC was better than HT. At low RHs (RH ≤ 10%), the factor that controls EWC is water moleculesactive sites interactions and one to two water molecules are associated with each carboxyl group, while at medium RHs (10 < RH ≤ 92%) the amount of monolayer water and mesopore volume gain in signi cance and ca. two multilayer water molecules are bound to each monolayer water molecule. At high RHs (RH > 92%), EWC is determined by comprehensive factors such as macropores and cracks. Furthermore, EWC can be either higher or lower than residual water content (RWC) based on the RH within a threshold residual water level (ca. 5 to 16%). EWC was generally higher than RWC below a RWC of ca. 5% and the opposite relationship was observed for samples with RWC above ca. 16%. These provide information for the operation of lignite dewatering technique, the control of its water re-adsorption, and storage.

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Section: Introductionmentioning

confidence: 89%

“…Numerous studies showed that dewatered lignite with different RWCs either re-adsorb or evaporate water at various RHs [6][7][8][9][10][11][12][13][14][15] . As reported by Shigehisa et al 6) and Charrière et al 15) , adsorption process includes three steps.…”

Section: Introductionmentioning

confidence: 99%

Effect of Hydrothermal Treatment Coupled with Mechanical Compression on Equilibrium Water Content of Loy Yang Lignite and Mechanism

et al. 2016

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“…8. Coal desorption isotherm results with CO 2 and CH 4 Unauthenticated Download Date | 5/10/18 1:13 PM Goodman et al, 2004;Medek et al, 2006;He et al, 2010), but also with water (McCutcheon & Barton, 1998;McCutcheon et al, 2002;Charrière & Behra, 2010). The hysteresis effect indicates that the sorbent/ sorbate system is in a metastable state and at decreasing pressure the gas is not readily released to the extent corresponding to the thermodynamic equilibrium value (Busch et al, 2003).…”

Section: Coal Desorption Isothermsmentioning

confidence: 99%

Influence of Coal Particle Size on Coal Adsorption and Desorption Characteristics

Zhang¹,

Aziz²,

Ren³

et al. 2014

Archives of Mining Sciences

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Accurate testing coal isotherm can play a significant role in the areas of coal seam gas drainage, outburst control, CO 2 geo-sequestration, coalbed methane (CBM) and enhanced coalbed methane recovery (ECBM) etc. The effect of particle size on the CO 2 and CH 4 sorption capacity of bituminous coal from Illawarra, Australia was investigated at 35°C and at pressure up to 4 MPa. A unique indirect gravimetric apparatus was used to measure the gas adsorption and desorption isotherms of coal of different particle sizes ranging from around 150 μm to 16 mm. Langmuir model was used to analysis the experimental results of all gases. Coal particle size was found to have an apparent effect on the coal ash content and helium density results. Coal with larger particle size had higher ash content and higher helium density. The sorption isotherm was found to be highly sensitive with helium density of coal which was determined in the procedure of testing the void volume of sample cell. Hence, coal particle size had a significant influence on the coal sorption characteristics including sorption capacity and desorption hysteresis for CO 2 and CH 4 , especially calculated with dry basis of coal. In this study, the 150-212 μm (150 μm) coal samples achieved higher sorption capacity and followed by 2.36-3.35 mm (2.4 mm), 8-9.5 mm (8 mm) and 16-19 mm (16 mm) particle size samples. However, the differences between different coal particles were getting smaller when the sorption isotherms are calculated with dry ash free basis. Test with 150 μm coal samples were also found to have relatively smaller desorption hysteresis compared with the other larger particle size samples. The different results including adsorption/desorption isotherm, Langmuir parameters and coal hysteresis were all analysed with the CO 2 and CH 4 gases.Keywords: coal adsorption, desorption, coal particle size, isotherm, Langmuir volume Dokładne zbadanie izoterm sorpcji na węglu odgrywa kluczową rolę w takich dziedzinach jak odgazowanie pokładów węgla, zapobieganie wybuchom, sekwestracja geologiczna CO 2 , odzysk metanu ze złoża. Wpływ wielkości ziaren na pojemność sorpcyjną bitumicznego węgla z Illawara (Australia) względem CO 2 i CH 4 zbadano w temperaturze 35°C przy ciśnieniu do 4 MPa. Wykorzystano oryginalną aparaturę do badań grawimetrycznych do zmierzenia izoterm adsorpcji i desorpcji na węglu w którym rozmiar ziaren wahał się od 150 μm do 16 mm. Analizę wyników doświadczalnych dla wszystkich gazów przeprowadzono w oparciu o model Langmuira. Stwierdzono, że rozmiary ziaren węglowych w znacznym stopniu warunkują zawartość popiołu i gęstość helową. Węgiel grubiej uziarniony charakteryzował się wyższą zawartością popiołu i większą gęstością helową. Wykazano, że izoterma sorpcji wykazuje wysoką wrażliwość na zmiany gęstości helowej, co stwierdzono na podstawie badania martwej przestrzeni ampułki w której umieszczono próbkę. Wnioskować stąd można, że rozmiar ziaren węgla w dużym stopniu wpływa na charakterystyki sorpcyjne węgla, w tym także na chłonność sorpcyjną i hi...

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“…La adsorción se incrementa a medida que aumenta la actividad de agua. Este comportamiento está de acuerdo con los estudios disponibles de la pareja sortiva carbón/agua [11,[15][16][17][31][32][33][34]. La cantidad de vapor de agua en los contenedores de adsorción se incrementa debido al aumento en la presión de vapor del sistema (actividad acuosa).…”

Section: Isotermas De Adsorciónunclassified

“…Se concluyó después de analizar los resultados que no existen diferencias significativas entre las isotermas de adsorción obtenidas por ambos métodos. Charrierre & Behra [17] reportaron las isotermas de adsorción -desorción en muestras de carbón bituminoso y en un carbón lignito. Las isotermas y las cinéticas de sorción de agua en carbón fueron estudiadas a una temperatura de 298K y un rango de presión relativa entre 0 y 0.95.…”

Section: Introductionunclassified

Effect of the temperature in adsorption phenomena of water onto Sub-Bituminous coal

2016

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The presence of water in coal presents a technological challenge for its industrial use in energetic processes. Therefore, this study aims to study the temperature effect on the water adsorption onto coals at 21, 30, 40 and 50°C. A Colombian bituminous coal was used as sample. The coal was characterized by nitrogen adsorption at 77 K (SBET), Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, elemental analysis (C-H-N elemental). The results showed that the water uptake increased as the vapor pressure increased. The Talu and Meunier model [1] was used to fit the adsorption isotherms, and the mean square root error (MSRE%) was lower than 10%. Additionally, the Gibbs free energy was found to have negative values, which corroborates the spontaneous adsorption process.Keywords: Adsorption; Coal; Isotherm; Water Efecto de la temperatura en el proceso de adsorción de agua en Carbón sub-bituminoso colombiano Resumen La presencia de agua en carbones presenta un reto tecnológico para su uso industrial en procesos energéticos. Por tal motivo, este estudio pretende analizar el efecto de temperatura en la adsorción de agua en carbones a 21, 30, 40 y 50°C. Un carbón sub-bituminoso Colombiano fue usado como muestra. El carbón fue caracterizado por adsorción de nitrógeno a 77K (SBET), Microscopía electrónica de barrido (SEM), Espectroscopia infrarroja por transformada de Fourier (FT-IR), análisis elemental (C-H-N). Los resultados muestran que la captura de agua se incrementa a medida que la presión de vapor aumenta. El modelo Talu & Meunier [1] fue utilizado para ajustar las isotermas de adsorción, presentando un buen ajuste. MSRE% menor al 10%. Adicionalmente, se calculó la energía libre de Gibbs obteniendo valores negativos, lo cual corrobora el proceso espontáneo de adsorción.

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Water sorption on coals

Cited by 237 publications

References 31 publications

Effect of Hydrothermal Treatment Coupled with Mechanical Compression on Equilibrium Water Content of Loy Yang Lignite and Mechanism

Effect of Hydrothermal Treatment Coupled with Mechanical Compression on Equilibrium Water Content of Loy Yang Lignite and Mechanism

Influence of Coal Particle Size on Coal Adsorption and Desorption Characteristics

Effect of the temperature in adsorption phenomena of water onto Sub-Bituminous coal

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