Improving sensitivity and accuracy of pore structural characterisation using scanning curves in integrated gas sorption and mercury porosimetry experiments

Hitchcock, Iain; Lunel, Marie; Bakalis, Serafim; Fletcher, Robin S.; Holt, Elizabeth M.; Rigby, Sean P.

doi:10.1016/j.jcis.2013.11.025

Cited by 28 publications

(27 citation statements)

References 25 publications

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“…As shown in Figure 5, Hitchcock et al (2014) pores to the large pores during the adsorption process. Accordingly, the sequence of filling in Figure 5(a) is D → C → B → A.…”

Section: Combination Of N 2 Ga and Mipmentioning

confidence: 96%

Variation in the Pore Structure of Coal after Hydraulic Slotting and Gas Drainage

Zou

Lin

Liang³

et al. 2014

Adsorption Science & Technology

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ABSTRACT:The integration of hydraulic slotting and gas drainage techniques has become a mainstream technique for enhancing permeability in coal seams with low permeability. However, the mechanism of action of this process is unclear. In this paper, field experiment and laboratory tests are described that aim at elucidating this process. Given the sensitivity and accuracy of test methods and their corresponding determination principles, a combination of mercury intrusion porosimetry and nitrogen gas adsorption was proposed as a complementary technique and the pore-size distribution (PSD) was obtained. It is shown that the proportion of minipores decreases remarkably, whereas that of the macropores gradually increases with the decrease in the distance from the slotted borehole. By contrast, the mesopores and micropores present insignificant changes. Meanwhile, the adsorption pore and the seepage pore show a similar variation in tendency with the minipores and macropores, respectively. Moreover, the specific surface area decreases substantially with the decrease in borehole distances. The integration of hydraulic slotting and gas drainage can lower the gas-adsorption properties and enhance the gas-seepage capacity within the disturbed zone significantly. The paper highlights the guiding factors for improving the enhanced coal bed methane recovery.

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“…As shown in Figure 5, Hitchcock et al (2014) pores to the large pores during the adsorption process. Accordingly, the sequence of filling in Figure 5(a) is D → C → B → A.…”

Section: Combination Of N 2 Ga and Mipmentioning

confidence: 96%

Variation in the Pore Structure of Coal after Hydraulic Slotting and Gas Drainage

Zou

Lin

Liang³

et al. 2014

Adsorption Science & Technology

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“…These effects are known as advanced [5] and delayed [6] filling (or condensation, or adsorption). These particular effects are pore-pore co-operative in nature, and thus the size of the effects is associated with the random inter-connectivity of pores of various different sizes within disordered solids, and, thence, studies of the more regular structures possessed by templated materials does not help to elucidate the actual extent of these problems in a given disordered material.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast, the novel integrated gas sorption and mercury porosimetry technique, which involves conducting a series of gas sorption and mercury porosimetry experiments on the same sample, can study pore-pore co-operative effects in particular sub-sets of pores within disordered samples by deconvolving-out the signal from 5 these pores. Previous work with this technique has demonstrated the existence of advanced adsorption of nitrogen in disordered silica gel materials [5], but has not studied delayed condensation. More recently the integrated gas sorption and mercury porosimetry technique has shown that there is a difference in the wetting of solid mercury relative to silica for nitrogen and argon adsorbates at their boiling points [8].…”

Section: Introductionmentioning

confidence: 99%

Detection of the delayed condensation effect and determination of its impact on the accuracy of gas adsorption pore size distributions

Rigby

Hasan

Hitchcock

et al. 2017

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk 1 normally requiring assumptions about the correct model for data analysis. In this work we present a novel method to both expand the range, and obtain greater accuracy, for the information obtained from the main boundary adsorption isotherms by using a combination of data obtained for two adsorptives, namely nitrogen and argon, both before and after mercury porosimetry. The method makes use of the fact that nitrogen and argon apparently 'see' a different pore geometry following mercury entrapment, with argon, relatively, 'ignoring' new metal surfaces produced by mercury porosimetry. The new method permits the study of network and pore-pore co-operative effects during adsorption that substantially affect the accuracy of the characteristic parameters, such as modal pore size, obtained for disordered materials. These effects have been explicitly quantified, for a typical sol-gel silica catalyst support material as a case study. The technique allowed the large discrepancies between modal pore sizes obtained from standard gas adsorption and mercury thermoporometry methods to be attributed to the network-based delayed condensation effect, rather than spinodal adsorption. Once the network-based delayed condensation effect had been accounted for, the simple cylindrical pore model and macroscopic thermodynamic Kelvin-Cohan equation were then found sufficient to accurately describe adsorption in the material studied, rather than needing a more complex microscopic theory. Hence, for disordered mesoporous solids, a proper account of inter-pore interactions is more important than that of intra-pore adsorbate density distribution, to obtain accurate pore size distributions. Detection of the Delayed Condensation Effect and Determination of its

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“…Recognizing the potential gain of a deeper insight into pore structure, and the growing power of modern adsorption equipment, scanning has been receiving increasing attention in both experimental and theoretical studies [18][19][20] . One of the earliest attempts to model the scanning process was the Independent Domain theory proposed by Everett 21 .…”

Section: Introductionmentioning

confidence: 99%

Hysteresis and scanning curves in linear arrays of mesopores with two cavities and three necks

Zeng

Tan

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Adsorption of argon at 87K in a linear array of slit mesopores composed of two cavities and three necks has been investigated using Grand Canonical Monte Carlo simulation. Hysteresis and scanning was found to depend on the relative size of the necks and cavities and on whether the necks are wider or narrower than the critical width that demarcates cavitation from pore blocking. There are 26 possible combinations for the linear array. By considering the behaviour of hysteresis scanning curves, we are able to identify four distinct groups: (i) Group 1: The descending scanning spans the boundary curve of the hysteresis loop due to stretching of the condensate in the small cavity.(ii) Group 2: The descending curve partially spans the loop and returns to the adsorption boundary. This occurs either because the condensate stretches in the small cavity, followed by evaporation via a pore blocking mechanism; or because the condensate evaporates as the meniscus recedes in the large neck that joins the two cavities.(iii) Group 3: The descending curve spans the loop as in Group 1 but there is a small sub-loop associated with emptying and filling of the large neck connecting the large cavity to the surrounding gas.

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Improving sensitivity and accuracy of pore structural characterisation using scanning curves in integrated gas sorption and mercury porosimetry experiments

Cited by 28 publications

References 25 publications

Variation in the Pore Structure of Coal after Hydraulic Slotting and Gas Drainage

Variation in the Pore Structure of Coal after Hydraulic Slotting and Gas Drainage

Detection of the delayed condensation effect and determination of its impact on the accuracy of gas adsorption pore size distributions

Hysteresis and scanning curves in linear arrays of mesopores with two cavities and three necks

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