The isokinetic effect as related to the activation energy for the gases diffusion in coal at ambient temperatures

Mianowski, A.; Marecka, A.

doi:10.1007/s10973-008-9058-3

Cited by 24 publications

(9 citation statements)

References 20 publications

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“…The negative DS = values for the dehydration process of the hydrate precursor indicate the higher orderliness of the activated state than the initial state. The results can be interpreted as a slow stage[44,49,50]. The positive values of DH = agree with the endothermic peak in the DTA upon dehydration reaction step.…”

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confidence: 63%

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Studies of thermal decomposition kinetics and temperature dependence of thermodynamic functions of the new precursor LiNiPO4·3H2O for the synthesis of olivine LiNiPO4

Kullyakool

Siriwong

Noisong

et al. 2015

J Therm Anal Calorim

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The olivine LiNiPO 4 was synthesized via the calcination of the new precursor LiNiPO 4 Á3H 2 O at 600°C. The precursor was obtained from low-temperature (50°C) wet chemical reaction. The results from XRD, FTIR, AAS/ AES and TG/DTG/DTA techniques confirmed the formula of the title compounds. The SEM results indicated the morphologies of the hydrate precursor as thin plate particles and the calcined product as small bead particles. The BET surface area of the final calcined product at 600°C is much higher (5.807 m 2 g -1 ) than that reported in the literature (0.25 m 2 g -1 ). The kinetic triplet [activation energy, E, pre-exponential factor, A, and the most probable mechanism function, g(a)] and the thermodynamic functions of activated complexes (DS = , DH = and DG = ) for the dehydration step of LiNiPO 4 Á3H 2 O were determined and discussed. The mechanism of the dehydration process is the single-step A 3/2 (assumed random nucleation and its subsequent growth). New information, namely the isobaric molar heat capacity, experimental entropy, enthalpy and Gibbs energy changes as function of temperature (K) of LiNiPO 4 Á3H 2 O and LiNiPO 4 , was evaluated from the DSC data by third-order polynomial fitting and reported for the first time. The calculated corresponding thermodynamic functions from kinetic parameters are compared and discussed.

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confidence: 63%

“…T i relates to the activation energy and pre-exponential factor [50][51][52]. According to the FTIR spectra, six vibrational band positions of water of crystallization (3440.…”

Section: Determination Of Iso-kinetic Temperaturementioning

confidence: 99%

Studies of thermal decomposition kinetics and temperature dependence of thermodynamic functions of the new precursor LiNiPO4·3H2O for the synthesis of olivine LiNiPO4

Kullyakool

Siriwong

Noisong

et al. 2015

J Therm Anal Calorim

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“…According to the results of their investigation, the diffusion rate in micropores had the highest rate for carbon dioxide rather than nitrogen and methane due to the small kinetic diameter of carbon dioxide (0.33 nm) than methane (0.38 nm) and nitrogen (0.36 nm). Moreover, they proposed that regarding the swelling of coal matrixes, which was a cause of gas adsorption, apparent diffusivity was decreased with the pressure increase. ,, Mianowski and Marecka (2008) reported that unipore diffusion model was not a good candidate model in the whole time of adsorption processes for methane and carbon dioxide. They concluded that the modified diffusion model, which will be described in the next section, would be a good fitting with experimental data …”

Section: Introductionmentioning

confidence: 99%

“…Moreover, they proposed that regarding the swelling of coal matrixes, which was a cause of gas adsorption, apparent diffusivity was decreased with the pressure increase. ,, Mianowski and Marecka (2008) reported that unipore diffusion model was not a good candidate model in the whole time of adsorption processes for methane and carbon dioxide. They concluded that the modified diffusion model, which will be described in the next section, would be a good fitting with experimental data …”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation and Mathematical Modeling of Gas Diffusivity by Carbon Dioxide and Methane Kinetic Adsorption

Davarpanah

Mirshekari

2019

Ind. Eng. Chem. Res.

114

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Gas transportation is of significance, especially in carbon dioxide sequestration and successful performances of enhanced methane recovery from shale layers. Among the three primary transportation mechanisms for the gas phase in shale layers, diffusion is considered as the most important phenomenon. The main objective of this comprehensive study is to propose a mathematical model of unipore diffusion and modified unipore diffusion to consider the kinetic adsorption of methane and carbon dioxide for two different shale samples at different pressure ranges. To validate the accuracy of this model, experimental investigations such as methane kinetic adsorption at pressure ranges of 3.2−9.3 MPa and carbon dioxide kinetic adsorption at pressure ranges of 2.5−6.5 were performed to compare with the results of the proposed model. The kinetics adsorption analysis for methane indicated that the required time for the completion of fractional uptake process is about 4−13 min, whereas for the adsorption of carbon dioxide it takes approximately 5−17 min to reach 70% fractional uptake for both shale samples. Subsequently, the modified unipore diffusion model provides a good agreement for both carbon dioxide and methane kinetic adsorption from gas shale layers.

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“…Some scholars have realised the importance of gas adsorption kinetics in coal and shale (Bhowmik and Dutta, 2013;Gasparik et al, 2014;Mianowski and Marecka, 2009). Methane adsorption rate data has been analysed for shale samples, showing a negative relation between the adsorption rate and pressure (Dang et al, 2017;Wang et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Investigation on the adsorption kinetics and diffusion of methane in shale samples

Zou

Rezaee

Yuan

2018

Journal of Petroleum Science and Engineering

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Shale gas is becoming increasingly important to mitigate the energy crisis of the world. Understanding the mechanisms of gas transport in shale matrix is crucial for development strategies. In this study, methane adsorption kinetics in shale samples were measured under different pressures and temperatures. The results of methane adsorption rate were fitted by the bidisperse diffusion model. Pore structure of the shale samples were characterized by lowpressure N2 and CO2 adsorption. The results showed that pressure has a negative effect on methane adsorption rate and diffusion, while the effect of temperature is positive. Combining the total organic carbon (TOC) and pore structure, methane adsorption rate and effective diffusivity were compared between all the shale samples. The methane adsorption rate under high pressure (50bar) is positively related to the TOC content. The micropore volume showed a moderate positive relation with the methane adsorption rate at 30bar. A weak positive relation exists between the TOC and effective diffusivity at low pressure and the effective diffusivity at low pressure shows an increasing trend with micropore(<2nm) volume. A hypothetic pore model is proposed: micropore in shales controls gas diffusion as pore throat which connects pores.

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The isokinetic effect as related to the activation energy for the gases diffusion in coal at ambient temperatures

Cited by 24 publications

References 20 publications

Studies of thermal decomposition kinetics and temperature dependence of thermodynamic functions of the new precursor LiNiPO4·3H2O for the synthesis of olivine LiNiPO4

Studies of thermal decomposition kinetics and temperature dependence of thermodynamic functions of the new precursor LiNiPO4·3H2O for the synthesis of olivine LiNiPO4

Experimental Investigation and Mathematical Modeling of Gas Diffusivity by Carbon Dioxide and Methane Kinetic Adsorption

Investigation on the adsorption kinetics and diffusion of methane in shale samples

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