Mercury Porosimetry Experiments Research Articles

3D Stochastic Network Modeling and Investigation of Network Size Effect on the Porous Media Structure of Ion Exchange Catalyst Amberlyst-35 with Computer Programs

In the present paper, the investigation was focused on the physical characterization and determination of porosity for an ion exchange catalyst called Amberlyst-35, which produces environmentally benign gasoline using 3D network modeling (3DNM). In addition, the effect of the different pore size distributions (PSD) has been investigated in porous media (PM). First, the mercury porosimetry (MPo) experiment was carried out to determine the porosity of the Amberlyst-35. Second, the KALINET program was run by Compact Visual Fortran (CVF) and Graphical Input/Output (GINO) for modeling porous structures. Then, the SECTION program was used for different porous 3D random images. The theoretical penetration curve was drawn using data obtained from the KALINET program and fitted to the experimental penetration values of Amberlyst-35 by changing the number of pores in each pressure interval of the PSD. The PSD was a 3D network model size of (N) = 30x30x30, 40x40x40, 50x50x50, which included 83,700-196,800-382,500 pores, respectively. On the other hand, various sections of the 3D stochastic images of the pore network were obtained from the SECTION program. Finally, 3D network images were drawn by the KALINET3D computer program. The MPo method has been applied using computer programs (with desktop computers). Moreover, it was found that the same results were obtained for both the theoretical and experimental data of MPo.

Fabric properties and electric efficiency limits of mechanical moisture extraction from fabrics

Residential clothes drying consume about 650 TBtu of primary energy per year in the United States, equivalent to 3% of primary residential energy consumption. There is a strong impetus to reduce the energy consumption of clothes dryers by both improving existing technology and developing alternatives that use fundamentally different drying mechanisms. Clothes drying technologies are broadly classified into either evaporative or mechanical drying. The focus of this paper is on mechanical drying, including vibrational, centrifugal, and press-based methods. In this work, the physical processes involved in these mechanical fabric drying processes were analyzed to develop general theories of mechanical cloth drying energy efficiency. Quantitative evaluation of the theories requires measured fabric properties. To accomplish this, a set of experiments was conducted on samples of a standard test fabric. The fabric was a cotton-polyester blend specified by the US Department of Energy to evaluate the standardized efficiency of all residential clothes dryers in the US. Mercury porosimetry experiments were conducted to determine the fabric pore size distribution, apparent density, and porosity. Elasticity experiments were conducted to determine the fabric’s Young’s modulus. Isostatic press experiments were conducted to establish a relationship between compression force and fabric moisture content. The data resulting from these experiments were combined with mathematical models developed in this work to calculate the theoretical maximum performance limits for mechanical drying of the standard fabric. The results of the analysis are used to make recommendations for the most promising technologies that offer the greatest potential energy savings for residential clothes drying.

Pore structural evolution of shale following thermochemical treatment

Abstract Shales experience heat treatment concurrent with the presence of water or steam during reservoir engineering interventions, such as high pressure water fracking and in-situ combustion of hydrocarbons. This work utilises a novel technique, which is a combination of gas sorption overcondensation and integrated mercury porosimetry experiments, not used before for any type of porous material, to study the pore structure of a shale rock, and its evolution following thermal treatment in the presence of water. Overcondensation allows the extension of gas sorption beyond the limits of conventional experiments to enable direct study of macroporosity. Scanning curve experiments, initiated from the complete boundary desorption isotherm, that can only be obtained for macropores by overcondensation experiments, has revealed details of the relative pore size spatial disposition within the network. In particular, it has been found that the new large voids formed by treatment are shielded by relatively much narrower pore windows. Use of a range of different adsorbates, with differing polarity, has allowed the chemical nature of the pore surface before and after treatment to be probed. Integrated rate of gas sorption and mercury porosimetry experiments have determined the level of the particular contribution to mass transport rates of the newly introduced porosity generated by thermal treatment. Combined CXT and mercury porosimetry have allowed the mapping of the macroscopic spatial distribution of even the new mesoporosity, and revealed the degree of pervasiveness of the new voids that leads to a thousand-fold increase in mass transport on thermal treatment.

Adsorption and diffusion of CO2 in CPO-27\u2013Ni beads

The present work involves the scale-up and characterization of CPO-27–Ni metal organic framework using a range of experimental techniques aimed at determining equilibrium and kinetic parameters to assess its potential for post-combustion carbon capture. CPO-27–Ni was prepared from its precursors by molecular gastronomy methods in kilogram scale. Adsorption of isotherms of pure CO2 and N2 were obtained for different temperatures on these beads, using a volumetric apparatus and the isotherms were fitted to a dual-site Langmuir model. A series of experiments were then carried out in the volumetric apparatus by dosing a known volume of CO2 and the pressure was monitored with time. The diffusional time constants were then extracted by fitting the series of curves to an isothermal diffusion model. From the time constants, the values of the diffusivities were obtained and compared with the values obtained from first principles correlations, which employed the pore size, and the porosity values from independent mercury porosimetry experiments. The results from the analysis showed that the transport of CO2 in the beads was well described by a combination of Knudsen and viscous diffusion mechanisms. Experiments were also carried out using a zero-length column (ZLC) apparatus by preparing a 10% CO2–He and 10% CO2–N2 mixture. The analysis of the ZLC curves showed that the two different carrier gases had an effect of the long-time slope, indicating the presence of a macropore-controlled diffusion mechanism.

Adsorption Contraction Mechanics: Understanding Breathing Energetics in Isoreticular Metal-Organic Frameworks.

A highly porous metal–organic framework DUT-48, isoreticular to DUT-49, is reported with a high surface area of 4560 m2·g–1 and methane storage capacity up to 0.27 g·g–1 (164 cm3·cm–3) at 6.5 MPa and 298 K. The flexibility of DUT-48 and DUT-49 under external and internal (adsorption-induced) pressure is analyzed and rationalized using a combination of advanced experimental and computational techniques. While both networks undergo a contraction by mechanical pressure, only DUT-49 shows adsorption-induced structural transitions and negative gas adsorption of n-butane and nitrogen. This adsorption behavior was analyzed by microcalorimetry measurements and molecular simulations to provide an explanation for the lack of adsorption-induced breathing in DUT-48. It was revealed that for DUT-48, a significantly lower adsorption enthalpy difference and a higher framework stiffness prevent adsorption-induced structural transitions and negative gas adsorption. The mechanical behavior of both DUT-48 and DUT-49 was further analyzed by mercury porosimetry experiments and molecular simulations. Both materials exhibit large volume changes under hydrostatic compression, demonstrating noteworthy potential as shock absorbers with unprecedented high work energies.

Fractal analysis of high rank coal from southeast Qinshui basin by using gas adsorption and mercury porosimetry

In order to better understand the pore structure of high rank coal, low-temperature N2 isotherm adsorption/desorption and mercury porosimetry experiments were conducted on 20 coal samples from the southeast Qinshui basin. Fractal analysis was used to characterize the heterogeneity of pore structure. To obtain credible fractal dimension of pores, several models for calculating the fractal dimension were used and their calculation results were compared. The results show that fractal dimensions of pore surface and structure in adsorption pores can be obtain by Frenkel-Halsey-Hill (FHH) model from type A of N2 adsorption isotherms. The mercury intrusion data reflect the fractal information about seepage pores and partial transition pores. Because sensitivities of various models on pores with different widths are different, fractal dimensions obtained from different models based on mercury intrusion data are inconsistent. The coal samples can be divided into three types according to the crossplot of the volume percentage of seepage pore and the ratio of fixed carbon content and volatile content. For type I and II, Langmuir volume is positively correlated with the pore structure fractal dimension of transition pores and micropores. This shows that high pore structure fractal dimension of adsorption pores related to more small pores is conducive to coalbed methane (CBM) enrichment. The relationships between fractal dimension and permeability in type I and II are different, which may be related to volume and connectivity of mesopores and macropores. For type III, high ash content greatly reduces the adsorption and seepage capacity of coal.

Structure-transport relationships in disordered solids using integrated rate of gas sorption and mercury porosimetry

This work describes a new experimental approach that delivers novel information on structure-transport relationships in disordered porous pellets. Integrated rate of adsorption and mercury porosimetry experiments have been used to probe the relative importance of particular sub-sets of pores to mass transport rates within the network of two disordered porous solids. This was achieved by examining the relative rates of low pressure gas uptake into a network, both before, and after, a known set of pores was filled with frozen, entrapped mercury. For catalyst pellets, formed by tableting, it has been found that the compaction pressure affects the relative contribution to overall mass transport made by the subset of the largest pores. Computerised X-ray tomography (CXT) has been used to map the spatial distribution of entrapped mercury and revealed that the relative importance of the sub-sets of pores is related to their level of pervasiveness across the pellet, and whether they percolate to the centre of the pellet. It has been shown that a combination of integrated mercury porosimetry and gas sorption, together with CXT, can comprehensively reveal the impact of manufacturing process parameters on pellet structure and mass transport properties. Hence, the new method can be used in the design and optimisation of pellet manufacturing processes.

Geologic controls of the production of coalbed methane in the Hancheng area, southeastern Ordos Basin

The Hancheng area of the southeastern Ordos Basin is a sample area for coalbed methane (CBM) development in China. There are three target coal seams for CBM development in this area, but the gas production of the different coal seams varies significantly. This study investigates the controlling factors of CBM production in the Hancheng area. The results indicate that permeability has the main impact on CBM production in the Hancheng area. Coal types and stress are closely related to fracture development and further impact on the permeability of coal reservoirs in this area. According to the macroscopic coal petrography description, mercury porosimetry experiments and X-CT scanning, bright coal has the largest pore volume and average pore size diameter than those of the other coal types and developed fractures with good openness and connectivity, whereas dull coal has the most undeveloped macropores and fractures. The No. 3 coal seam always has a higher productivity because it mainly consists of bright coal and semi-bright coal and has a relatively shallow buried depth. Therefore, the No. 3 coal seam had the best physical properties as a whole compared to the other coal seams, providing the most favourable conditions for CBM production.

Investigation of the effect of sol concentration on the microstructure and morphology of Novolac hyperporous

Novolac hyperporous materials were successfully synthesized using sol–gel polymerization of Novolac resin with hexamethylenetetramine (HMTA) catalyst in the solvent vapor saturated atmosphere, followed by subcritical drying. Mercury porosimetry results showed that these materials had large pore volume, more than 1cm3/g. SEM micrographs showed that these materials formed strongly cross-linked aggregates. Therefore, these results demonstrated that these materials would be termed as hyperporous materials.Novolac hyperporous materials can be either crushed or invaded by mercury during mercury porosimetry experiments. In this work, six samples with different initial sol concentration were examined. It has been shown here that a sample with higher porosity exhibited two volume variation mechanisms successively; compaction followed by intrusion, when submitted to mercury porosimetry that real result could be obtained by applying Pirard's collapse model below the pressure of transition, Pt, and Washburn's intrusion theory above Pt. Low porosity sample showed the collapse under mercury pressure only and no transient pressure could be observed. It means mercury does not penetrate the pore network, but the whole material is densified. Microstructure of these hyperporous materials directly influences mechanism changing from collapsing to intrusion.

Quels lasers et quels paramètres pour quelles lésions : discussion intéractive de cas cliniques

Novolac hyperporous materials were successfully synthesized using sol–gel polymerization of Novolac resin with hexamethylenetetramine (HMTA) catalyst in the solvent vapor saturated atmosphere, followed by subcritical drying. Mercury porosimetry results showed that these materials had large pore volume, more than 1 cm3/g. SEM micrographs showed that these materials formed strongly cross-linked aggregates. Therefore, these results demonstrated that these materials would be termed as hyperporous materials.Novolac hyperporous materials can be either crushed or invaded by mercury during mercury porosimetry experiments. In this work, six samples with different initial sol concentration were examined. It has been shown here that a sample with higher porosity exhibited two volume variation mechanisms successively; compaction followed by intrusion, when submitted to mercury porosimetry that real result could be obtained by applying Pirard's collapse model below the pressure of transition, Pt, and Washburn's intrusion theory above Pt. Low porosity sample showed the collapse under mercury pressure only and no transient pressure could be observed. It means mercury does not penetrate the pore network, but the whole material is densified. Microstructure of these hyperporous materials directly influences mechanism changing from collapsing to intrusion.

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

Gas sorption scanning curves are increasingly used as a means to supplement the pore structural information implicit in boundary adsorption and desorption isotherms to obtain more detailed pore space descriptors for disordered solids. However, co-operative adsorption phenomena set fundamental limits to the level of information that conventional scanning curve experiments can deliver. In this work, we use the novel integrated gas sorption and mercury porosimetry technique to show that crossing scanning curves are obtained for some through ink-bottle pores within a disordered solid, thence demonstrating that their shielded pore bodies are undetectable using conventional scanning experiments. While gas sorption alone was not sensitive enough to detect these pore features, the integrated technique was, and, thence, this synergistic method is more powerful than the two individual techniques applied separately. The integrated method also showed how the appropriate filling mechanism equation (e.g. meniscus geometry for capillary condensation equations), to use to convert filling pressure to pore size, varied with position along the adsorption branch, thereby enabling avoidance of the further systematic error introduced into PSDs by assuming a single filling mechanism for disordered solids.

Researches on Fractal Features of Graphite Porous Materials

The mercury porosimetry experiment has tested three different kinds of porosity graphite and the microscopic structure of impregnation antimony materials, and has calculated the corresponding fractal dimension by using the Menger model. The results show that: the main pore diameter of the graphite materials is in the interval of , most of which can be filled by impregnation antimony, and graphite and impregnation antimony materials both have the fractal characteristics. Graphite materials also have the dual fractal characteristics. Its fractal inflection point aperture is about 1μm, and the fractal dimension (3.05 ~ 3.25) of the small pores (φ≤1μm) is less than the one (3.71 ~ 3.95) of the large pores (φ>1μm). The reason why existing the dual fractal characteristics is that the size of the pore formation mechanism is different. Impregnation occurs mainly in the range of large pores, characteristics of which is an important factor to influence the quality of impregnation materials. The material formula is the main factor to influence the large pores and an important guarantee to improve the quality of impregnation products.

Characterization by Mercury Porosimetry of Nonwoven Fiber Media with Deformation

The porosity and pore diameter distribution are important characteristics of nonwoven fiber media. With the advent of electrospinning, the production of mats of nonwoven fibrous materials with fiber diameters in the 0.1–10 μm range has become more prevalent. The large compliance of these mats makes them susceptible to mechanical deformation under the pressures attained in a typical mercury porosimetry experiment. We report a theoretical analysis of the liquid volume measured during liquid intrusion porosimetry in the presence of deformation of such mats by one of two modes: buckling of the pores or elastic compression of the mat. For electrospun mats of poly(ε-caprolactone) with average fiber diameters ranging from 2.49 to 18.0 μm, we find that buckling is the more relevant mode of deformation, and that it can alter significantly the determination of pore diameter distributions measured by mercury porosimetry.

Textural and morphological study of activated carbon fibers prepared from kenaf

Activated carbon fibers (ACFs) are relatively novel fibrous adsorbents that show important advantages with respect to conventional activated carbons. In this work the influence of the preparation conditions on the fractal dimension and porous texture of ACFs prepared from kenaf by physical activation has been investigated. The kenaf fibers were first carbonized, the sample showing optimal textural properties (i.e., that carbonized at 400 °C for half an hour) being used as precursor for the activation treatment. This sample was subsequently activated between 500 and 700 °C for 2 and 4 h. All samples were characterized by N 2 adsorption at −196 °C, mercury porosimetry and scanning electronic microscopy (SEM). The adsorption data reveal that, in general, the textural parameters increase markedly with temperature and time. On the other hand, the mercury porosimetry experiments suggest that the macropore volume varies slightly in all the temperature and treatment time interval. The fractal dimension ( D) of the samples has been calculated for micropores by applying the Frenkel–Hansey–Hill (FHH) equation, whereas data from the mercury porosimetries were used to determine the fractal dimension corresponding to macropores.The variation pattern of D points out that, as temperature rises, the thermal treatment and the presence of activating agent favor the porous development of the samples. Finally, the SEM images suggest the occurrence of interconnection and opening of pores as well as of detachments of the external layers of the pores. As a consequence more homogeneous pores with smoother surfaces are observed.

Mercury Porosimetry in Mesoporous Glasses: A Comparison of Experiments with Results from a Molecular Model

We present results from experiments and molecular modeling of mercury porosimetry into mesoporous Vycor and controlled pore glass (CPG) solid materials. The experimental intrusion/extrusion curves show a transition from a type H2 hysteresis for the Vycor glass to a type H1 hysteresis for the CPG. Mercury entrapment is observed in both materials, but we find that the amount of entrapped mercury depends on the chosen experimental relaxation time. No additional entrapment is found in a second intrusion/extrusion cycle, but hysteresis is still observed. This indicates that hysteresis and entrapment are of different origin. The experimental observations are qualitatively reproduced in theoretical calculations based on lattice models, which provide significant insights of the molecular mechanisms occurring during mercury porosimetry experiments in these porous glasses.

Using Nano‐Cast Model Porous Media and Integrated Gas Sorption to Improve Fundamental Understanding and Data Interpretation in Mercury Porosimetry

AbstractThe mechanisms of entrapment, and the nanoscopic spatial distribution, of the residual mercury within nano‐cast and amorphous porous media (pore sizes ~1–100 nm) following high‐pressure penetration have been studied. It has been shown that, even at the nano‐scale, one of the same two principle mechanisms that have been observed previously in mercury porosimetry experiments on macroscopic glass pore models also occur within a given amorphous, nanoporous solid. Using percolation theory to interpret novel, integrated gas sorption experiments, entrapment was shown to arise, either because of the presence of sufficiently narrow pore necks interspersed between larger voids, or due to non‐random, longer‐range structural heterogeneity. The threshold "snap‐off" ratio parameter for the entrapment process has also been directly measured but found to be considerably smaller than seen previously for macroporous materials. The techniques employed here enable information not previously available for nanoporous systems to be determined, and therefore to be incorporated into simulations of mercury porosimetry on those materials.

Integrating Gas Sorption with Mercury Porosimetry

Previous work has shown that it is possible to use intergrated nitrogen sorption and mercury porosimetry experiments to determine the distribution of average pore length with pore diameter for mesoporous solids. In this work, the previous data analysis method has been generalised such that it is also suitable for application to samples with higher levels of mercury entrapment than before. This generalisation of the theory has facilitated the ability to use a series of progressively larger mercury scanning loops, in integrated gas sorption and porosimetry experiments, to potentially determine the full pore length distribution for pores of a given diameter, and the distribution of pore co-ordination number. The new analysis has been applied to a silica catalyst support.

Dynamic Aspects of Mercury Porosimetry: A Lattice Model Study

Grand canonical Monte Carlo simulations using both Glauber dynamics and Kawasaki dynamics have been carried out for a recently developed lattice model of a nonwetting fluid confined in a porous material. The calculations are aimed at investigating the molecular scale mechanisms leading to mercury retention encountered during mercury porosimetry experiments. We first describe a set of simulations on slit and ink-bottle pores. We have studied the influence of the pore width parameter on the intrusion/extrusion curve shapes and investigated the corresponding mechanisms. Entrapment appears during Kawasaki dynamics simulations of extrusion performed on ink-bottle pores when the system is studied for short relaxation times. We then consider the more realistic and complex case of a Vycor glass building on recent work on the dynamics of adsorption of wetting fluids (Woo, H. J.; Monson, P. A. Phys. Rev. E 2003, 67, 041207). Our results suggest that mercury entrapment is caused by a decrease in the rate of mass transfer associated with the fragmentation of the liquid during extrusion.

Interfacing Mercury Porosimetry with Nitrogen Sorption

AbstractCombinations of gas sorption and mercury porosimetry experiments have been run in series on the same sample. This has been achieved by freezing entrapped mercury in place before a subsequent gas sorption experiment was carried out. Several different bidisperse materials with similarly shaped mercury intrusion curves and similar levels of mercury entrapment have been studied. The entrapment of mercury within certain pores in the porous medium can often lead to marked changes in the shape of the gas sorption hysteresis loop between the data obtained prior and subsequent to porosimetry. It was found that the degree of the change of shape of the sorption hysteresis loops differed markedly between different materials. The analysis of the gas sorption hysteresis loops using percolation theory has allowed information to be obtained on the pore length distribution, and/or the distribution of pore co‐ordination number and the spatial arrangement of pores within the sample, in addition to the pore connectivity and lattice size usually obtained. The interfaced experiments have also allowed the internal consistency of analysis methods based on percolation theory to be tested, semi‐empirical alternatives to the Washburn Equation for the analysis of raw mercury porosimetry data to be independently validated, and the mechanisms of mercury entrapment in various samples to be determined.

Modeling mercury porosimetry using statistical mechanics.

We consider mercury porosimetry from the perspective of the statistical thermodynamics of penetration of a nonwetting liquid into a porous material under an external pressure. We apply density functional theory to a lattice gas model of the system and use this to compute intrusion/extrusion curves. We focus on the specific example of a Vycor glass and show that essential features of mercury porosimetry experiments can be modeled in this way. The lattice model exhibits a symmetry that provides a direct relationship between intrusion/extrusion curves for a nonwetting fluid and adsorption/desorption isotherms for a wetting fluid. This relationship clarifies the status of methods that are used for transforming mercury intrusion/extrusion curves into gas adsorption/desorption isotherms. We also use Monte Carlo simulations to investigate the nature of the intrusion and extrusion processes.