Corrugated Pore Structure Model Research Articles

Tortuosity quantification of fly ash concrete considering interfacial transition zone

For concrete materials, durability is closely related to the mass transport property. The tortuosity of concrete material is an important factor accounting for the transport property. In this paper, the tortuosity of concrete is studied by mercury intrusion porosimetry and permeation tests in order to consider the existence of aggregate induced in the interfacial transition zone (ITZ). Tortuosity gained through the corrugated pore structure model and the Katz–Thompson model are compared and analysed to quantify the tortuosity of fly ash concrete. The ITZ was observed by scanning electron microscopy. The results show that the effect of aggregate should be considered when studying the tortuosity of concrete materials. With an aggregate value fraction of 43.8%, when considering the ITZ around coarse aggregate, concrete tortuosity is 1.29–16.18 times higher than that of the mortar matrix.

A comprehensive nitrogen adsorption measurement on the pore structure of calcium-silicate-hydrate subjected to cryogenic attack

This study carried out a comprehensive nitrogen adsorption evaluation on the cryogenic attack impacts on the micropores and mesopores of calcium-silicate-hydrate (C-S-H). Pore volume and pore size distribution were analyzed by using Barrett-Joyner-Halenda (BJH), non-local density function theory (NLDFT), Dubinin-Radushkevich (DR), and Horvath-Kawazoe (H-K) methods. Surface fractal dimensions were analyzed by Frenkel-Halsey-Hill (FHH) model. The tortuosity factors were estimated using the corrugated pore structure model (CPSM) simulation. Results show that the cryogenic attack may chemically transform C-S-H surface, leading to a higher attraction to the adsorbates. The mesopores of C-S-H with a high Ca/Si ratio were better preserved. Furthermore, the ultramicropores and small supermicropores are more sensitive to the cryogenic attack than those larger micropores. In addition, it is found that the cryogenic attack has a significant influence in increasing the complexity and irregularity of the C-S-H mesopore structure. The CPSM simulation results provide additional evidence for the microcrack formation.

Nanoporous Activated Carbon Derived via Pyrolysis Process of Spent Coffee: Structural Characterization. Investigation of Its Use for Hexavalent Chromium Removal

Hexavalent chromium (Cr(VI)) is a heavy metal that is highly soluble and exhibits toxic effects on biological systems. Nevertheless, it is used in many industrial applications. The adsorption process of Cr(VI), using activated carbon (AC), is under investigation globally. On the other hand, around six million tons of spent coffee is sent to landfill annually. In the spirit of cyclic economy, this research investigated the production of AC from spent coffee for the removal of Cr(VI) from wastewater. The AC was produced via pyrolysis process under a nitrogen atmosphere. Chemical activation using potassium hydroxide (KOH) occurred simultaneously with the pyrolysis process. The produced AC was tested as an absorber of Cr(VI). The best fitted kinetic model was the diffusion–chemisorption model. A 24-h adsorption experiment was carried out using a solution with a pH of 3 and an initial Cr(VI) concentration of 54.14 ppm. This resulted in an experimental maximum capacity of 109 mg/g, while the theoretical prediction was 137 mg/g. It also resulted in an initial adsorption rate (ri) of 110 (mg/(g h)). The Brunauer–Emmett–Teller surface area (SgBET) was 1372 m2/g, the Langmuir surface area (SgLang.) was 1875 m2/g, and the corrugated pore structure model surface area (SgCPSM) was 1869 m2/g. The micropore volume was 84.6%, exhibiting micropores at Dmicro1 = 1.28 and Dmicro2 = 1.6 nm. The tortuosity factor (τ) was 4.65.

Improved efficiency of sol–gel synthesized mesoporous anatase nanopowders in photocatalytic degradation of metoprolol

The structural and morphological properties of mesoporous anatase nanopowders, synthesized by sol–gel method, have been modified by varying the duration of calcination, in order to obtain more efficient photocatalyst than Degussa P25 in the degradation of relatively large pollutant molecules (>1nm in size). According to X-ray diffraction analysis, the crystallite size was increased from 13 to 17.5nm with the increase of calcination time from 1 to 7h. The analysis of nitrogen sorption experimental data revealed that all samples were mesoporous, with a mean pore diameters in the range of ∼5–9nm. The corrugated pore structure model was employed to evaluate pore structure tortuosity. Nanopowder properties have been related to the photocatalytic activity, tested in the degradation of metoprolol tartrate salt, selective β1-blocker used in a variety of cardiovascular diseases, with molecular size of 0.610nm×1.347nm. The study has demonstrated that samples calcined for 4 and 5h have displayed higher photocatalytic performance than Degussa P25, whereas the sample calcined for 3h has shown comparable activity.

Evaluation of hydrogen permselective separation from “synthesis gas” components based on single gas permeability measurements on anodic alumina membranes

Anodic alumina membranes were prepared by anodizing aluminum followed by chemical and hydrothermal treatments. Anodization was performed on both tube surfaces. External anodization was restricted to selected spots leaving an aluminum mechanically strong frame. Nitrogen sorption data analysed with the CPSM method (Corrugated Pore Structure Model) detected a mesopore structure (i.e. D mean;15–20) and surface areas of 2–20 m 2/g. SEM microscopy images revealed a regular pore structure of independent pores with densities of N pore ~ 5.6 × 10 14 pores/m 2. Single gas permeances (Π) for X: H 2, CH 4, CO and CO 2 were measured on a Wicke–Kallenbach apparatus at varying mean transmembrane pressure P m by the “dead-end” method. The observed slight dependence of Π on Ρ m is indicative of strong Knudsen diffusion and weak viscous flow contributions. By correlating the experimental data with a linear Π vs Ρ m relationship, Knudsen contribution evaluation was enabled, and found to vary in the range K C ≈ 0.7–1.0. The Knudsen number criterion for flow regime discrimination is critically discussed and a realistic dual Knudsen number approach is proposed. Experimental permselectivities α Η2Χ = Π H2/Π X (X ≠ H 2) approach by 70–100% their Knudsen selectivity counterparts. Anodic alumina membranes exhibit pore structure and gas permeability characteristics useful in designing integrated gas separation and catalytic membrane reactor systems.

PREPARATION AND CHARACTERIZATION OF ANODIC ALUMINUM OXIDE FILMS EXHIBITING MICROPOROSITY

Anodic alumina materials exhibiting regular pore structure, microporosity, and extensive surface areas were prepared and characterized. The effects of current density, (J = 12–35 mA/cm2), anodization time (t = 30–150 min), and hydrothermal treatment on pore structure were investigated. Nitrogen sorption hysteresis was simulated using the corrugated pore structure model (CPSM). Pore size distributions, relative specific surface area (SCPSM/Sext = 870–8645), microporosity (max ∼ 33.0%), pore tortuosity (TCPSM = 3.1–5.7), pore connectivity (c = 3.02–4.85, Seaton's model), and nominal pore length values (i.e., Ns = 3–10, from CPSM, and L = 0.91–1.20, Seaton) were evaluated. Pore sizes dpore > 13 nm deduced via CPSM simulation of gas sorption data were also detected by SEM imaging. A minimum external surface pore density of ∼ 7.5 × 1010 pores/cm2 was evaluated from the SEM micrograph. Anodization conditions and the following treatment caused a severe pore structure change. Pore tortuosity (TCPSM) changes inversely proportionally to pore connectivity (c), while the nominal pore length (Ns) varies proportionally to the number of pore length (L). It is concluded that materials possessing microporosity, regular pore architectures, and high surface areas can become potential candidate membranes for gas separation and catalytic reaction applications. They can also be used as templates in electrochemical applications (e.g., solar and fuel cells).

Porous structure of natural and modified clinoptilolites

The evaluation of the pore-size distribution (PSD) of natural and modified mesoporous zeolites, i.e., clinoptilolites is presented. We demonstrate the SEM results showing that the pores of fracture-type from 25–50 nm to 100 nm in size between clinoptilolite grains, as well as pores between crystal aggregates up to 500 nm in size are present in the studied material. The detailed distribution of pore sizes and tortuosity factor of the above-mentioned materials are determined from the adsorption–desorption isotherms of nitrogen measured volumetrically at 77 K. To obtain the reliable pore size distribution (PSD) of the above-mentioned materials both adsorption and desorption branches of the experimental hysteresis loop are described simultaneously by recently developed corrugated pore structure model (CPSM) of Androutsopoulos and Salmas. Evaluated pore size distributions are characterized by well-defined smooth peaks placed in the region of the mesoporosity. Moreover, the mean pore diameter calculated from the classical static measurement of nitrogen adsorption at 77 K correspond very well to the pore diameters from SEM, showing the applicability of the CPSM for characterization of the porosity of natural zeolites. We conclude that classical static adsorption measurements combined with the proper modeling of the capillary condensation/evaporation phenomena are a powerful method which can be applied for pore structure characterization of natural and modified clinoptilolites.

Rigid Sphere Molecular Model Enables an Assessment of the Pore Curvature Effect upon Realistic Evaluations of Surface Areas of Mesoporous and Microporous Materials

A gas adsorption rigid spheres model (RSM) was incorporated into the CPSM model (corrugated pore structure model) to correlate the pore surface areas obtained from the BET and CPSM methods. The latter is a method simulating the gas sorption hysteresis loop and enables the evaluation of surface areas S(CPSM) through the integration of the pertinent pore size distributions. Thus, S(CPSM) values are inherently influenced by pore curvature. The new CPSM-RSM version estimates surface areas S(CPSMfs) that are independent of pore curvature and can be compared with the pertinent S(BET) values. The RSM exploits the fact that a curved pore surface accommodates fewer molecules, assumed to behave as rigid spheres, than an equal flat one. Thus, the RSM accounts for a higher molecular surface coverage Ac (nm2/molec.) in pores with marked curvature than that (i.e., Af) on a flat surface. The ratio Ac/Af for nitrogen adsorbed on single pore sizes varies in the range Ac/Af = 1.44-1.03 for pore sizes D = 1.5-15 nm, respectively. Also for D = 1.5-5.0 nm the S(CPSMfs) and S(BET) values are lower by approximately 10-45% than the S(CPSM) estimates. From the application of the CPSM-RSM model on several porous materials exhibiting all known types of sorption hysteresis loops, it was confirmed that S(BET) approximately S(CPSMfs) (+/-5%) and (S(CPSM) - S(BET))/S(BET) = 3-68% for the materials examined. In conclusion, the BET method may produce quite conservative surface area estimates for materials exhibiting pore structures with appreciable pore curvature, whereas the CPSM-RSM model can reliably predict both S(CPSM) and S(CPSMfs) = S(BET) values.

A Monte Carlo pore network for the simulation of porous characteristics of functionalized silica: pore size distribution, connectivity distribution and mean tortuosities

The simulation of the random porous network of five samples of functionalized SiO 2 took place using a dual-site-bond model (DSBM) and Monte Carlo techniques for achieving the proper arrangement of the pores into the system. The simulation took place in 7 × 7 × 7 lattice. As a starting point of simulation the adsorption branch of N 2 isotherm was considered from which the pore size distribution was estimated. Then as a benchmark of simulation the N 2 desorption branch was considered whose fitting was achieved using the Monte Carlo technique for selecting the proper place of each pore into the 7 × 7 × 7 lattice. From the obtained model, it was possible to estimate the distribution of pore connectivities of each system. The mean value of those connectivity distributions tallies with the corresponding mean values estimated using the standard methodology of Seaton. In addition, the mean tortuosity of the porous network was estimated and the results were favorably compared with values of tortuosity estimated recently via the so-called corrugated-pore-structure-model (CPSM) for the same solids. The degree of functionalization of the parent SiO 2 affects both connectivity and tortuosity in a linear way. Some discrepancies observed between the results obtained via this methodology and the ones obtained using the Seaton or the CPSM model are discussed.

Evaluation of Microporosity, Pore Tortuosity, and Connectivity of Montmorillonite Solids Pillared with LaNiOx Binary Oxide. A Combined Application of the CPSM Model, the αs-Plot Method and a Pore Percolation−Connectivity Model

The present work deals with the comparative application of the CPSM (corrugated pore structure model), the αs plot and the pore connectivity methods for pore structure analysis and especially the detection of microporosity of a category of montmorillonite clays pillared with LaNiOx binary oxide. A quite good agreement between the corresponding results deduced from the three methods was confirmed. The raising of the LaNiOx content caused a change of pore volume, surface area, and microporosity whereas the relevant curves pass through a maximum. The CPSM model, through the simulation of gas sorption hysteresis, enables the evaluation of unified mesomicropore size distributions, pore surface areas, tortuosity factors, τCPSM, and relative microporosities. It is also concluded that pore tortuosity, (τCPSM), is inversely proportional to the pore connectivity factor (c), and the nominal pore length (Ns) (i.e., a CPSM parameter) is proportional to the number of pore lengths (L) (i.e., a parameter of the pore conn...

Relationships among Pore Size, Connectivity, Dimensionality of Capillary Condensation, and Pore Structure Tortuosity of Functionalized Mesoporous Silica

Seven mesoporous forms of silica were prepared by controlled and gradual functionalization of the original SiO2 surface with silano-(trimethoxy)-propyl-imidazole groups. The degree of surface functionalization was n = 0.00, 0.23, 0.30, 0.40, 0.52, 0.60, and 0.85 and was controlled by previous knowledge of surface acidity, determined by temperature-programmed desorption of NH3. From N2 adsorption/desorption measurements, the specific surface area Sp (m2 g-1), the specific pore volume Vp (cm3 g-1), and the corresponding pore size distributions (PSDs) were determined. The connectivity c of the solids was also calculated according to the method of Seaton, and the dimensionality of capillary condensation Dcc was found using the thermodynamic method of Neimark. The increase of functionalization resulted in a linear drop of Sp and Vp, and the maximum Dmax of the PSD and the full width at half-maximum, fwhm ∼ 2σ, of the distribution drop in a regular way whereas the ratio (Dmax/2σ) remains practically constant. The connectivity c also decreases from c = 12.5 at n = 0 to c = 3 at n = 0.60−0.85, presumably because of blocking of channels connecting various pores. The Dcc values decrease with increasing n values. Next, the co-called corrugated pore structure model, CPSM, was employed for the estimation of tortuosity τ of the porous solids and the simulation of the experimental adsorption/desorption isotherms. From those CPSM simulations, the corresponding specific surface area SCPSM (m2 g-1), the specific pore volume VCPSM (cm3 g-1), and the corresponding pore size distribution PSDCPSM were estimated. The tortuosity τ of the system drops with the degree of functionalization from τ = 4.22 at n = 0 to τ = 3.37 at the initial functionalization (n = 0.23) and subsequently remains practically constant at about τ = 3.40 ± 0.10, for the same reasons which affect the connectivity, that is, blocking of various pore channels. The comparison between the parameters Vp and VCPSM is quite satisfactory. The SCPSM values appear systematically higher by 8−23% compared to the Sp ones. The dimensionality of capillary condensation Dcc is related to the variance 2σ of the PSD. The reasons and the limits of this relationship are discussed.

Pore Structure−Chemical Composition Interactions of New High Surface Area Manganese Based Mesoporous Materials. Materials Preparation, Characterization, and Catalytic Activity

The present article deals with pore structure−chemical composition interactions of new high surface area manganese based porous mixed oxides (MANPOs). These mixed oxidic materials were prepared by the dropwise addition of a solution containing metal nitrate into an acetonic solution containing the trinuclear complex of manganese [Mn3O(CH3COO)6(pyr)3]ClO4, which is water sensitive. The CPSM model (corrugated pore structure model) was employed in pore structure investigations of the MANPO materials containing Al, Fe, La, La + Ce, and La + Sr. Successful CPSM simulations of nitrogen sorption hysteresis loops for the MANPO solids enabled the evaluation of intrinsic pore size distributions (PSDs) and tortuosity factors. The latter vary over the approximate range τCPSM = 3.0−5.7 (i.e. τCPSM≈ 3 for materials containing Al or Fe and τCPSM = 4.7−5.7 for those containing La, La + Ce, or La + Sr). These values are typical of porous catalysts and are higher than those reported for MCM-41 materials (ca. τCPSM = 1.00−2...

Mercury Porosimetry: Contact Angle Hysteresis of Materials with Controlled Pore Structure

Mercury Porosimetry (MP) hysteresis is a commonly observed phenomenon in which mercury retention disguises further the overall hysteresis picture. This article introduces a new interpretation of the MP hysteresis based on the combined effect of pore structure networking and mercury contact angle variation occurring between the mercury penetration and retraction operations. To distinguish the contribution of each factor the following investigations were carried out. Nitrogen sorption (NP) and MP experiments were performed on samples of an anodic aluminum membrane and the results were interpreted in terms of the Corrugated Pore Structure Model (CPSM), i.e., CPSM-Nitrogen and CPSM-Mercury models, respectively. The simulation of the observed hysteresis data using the CPSM model enabled the evaluation of an identical for the two methods intrinsic pore size distribution (PSD) and cumulative surface area in perfect agreement with the respective BET value. Additionally, the CPSM analysis of data resulted in the evaluation of mercury contact angles, i.e., θp=143° and θr=101.7° for the MP penetration and retraction branches of the hysteresis loop, respectively. Moreover, CPSM-Mercury simulations of literature MP hysteresis data, valid for controlled-pore glasses and nuclepore membranes, led to the evaluation of contact angles, i.e., glasses: θp=143°, θr=100.5–107.5° and nuclepore: θp=143°, θr=118– 121°. The latter values are comparable with relevant literature data and approximate those determined for the anodic aluminum membrane. The CPSM model employed herein proved to be a flexible and reliable model for simulating the pertinent hysteresis loops by combining pore networking and contact angle hysteresis phenomena.

An investigation of the physical structure of MCM-41 novel mesoporous materials using a corrugated pore structure model

The preparation and pore structure characterization of MCM-41 materials with or without Al or Ti addition during synthesis are presented in this work. Such solids are intended for use as catalysts supports possessing advantageous pore structure, total acidity and thermal stability characteristics. BET surface areas up to 1483 m 2/g were determined and compared with cumulative surface areas obtained by methods like the conventional Roberts’ and the newly reported corrugated pore structure model-nitrogen (CPSM-nitrogen) [Ind. Eng. Chem. Res. I 39 (2000) 3747; Ind. Eng. Chem. Res. II 39 (2000) 3764]. CPSM predictions are in perfect agreement with estimates obtained by the BET monolayer adsorption variant. Pore size distributions (PSDs) were deduced by using both the Roberts’ and the CPSM methods. The superiority of the latter method was confirmed, since apart from the prediction of intrinsic PSDs, enabled the determination of tortuosity factors ranging ca. τ CPSM=1–2.35, for the studied materials [Ind. Eng. Chem. Res. 40 (2000) 721]. These values are lower than those for traditional catalysts ca. τ=3–10 [Mass Transfer in Heterogeneous Catalysis, 1970, p. 37] and reflect the ordered pore structure of MCM-41 solids. Addition of Al (i.e. Si/Al=5) caused a PSD shift towards the micropore region (i.e. D mean shift from 3.28 to 2.10 nm) in contrast to Ti addition (i.e. Si/Ti=5) that caused a PSD shift farther to the mesopore region (i.e. D mean shift from 3.28 to 23.74 nm). Lower additions of Al or Ti (i.e. Si/Al=20 and Si/Ti=10) caused a pore volume and surface area reduction but not a substantial shift of the intrinsic PSDs.

Pore structure analysis of an SCR catalyst using a new method for interpreting nitrogen sorption hysteresis

Nitrogen sorption hysteresis of a selective catalytic reduction (SCR) catalyst in its “fresh” and “used” form [Catal. Today 56 (2000) 335] was analysed by employing the Corrugated Pore Structure Model (CPSM-nitrogen) reported elsewhere [Ind. Eng. Chem. Res. 39 (2000) 3747 and Ind. Eng. Chem. Res., 39 (2000) 3764]. The BET surface area and intrinsic pore volume, and surface area distributions were deduced via the CPSM fitting over the relevant hysteresis loop and compared to those obtained by applying various conventional methods. CPSM predictions of the total specific pore surface area, are in perfect agreement with BET estimates, while those calculated by the Roberts method, irrespective of the hysteresis loop branch chosen, deviate substantially. CPSM prediction of tortuosity factors (CPSM-tortuosity [Ind. Eng. Chem. Res., in press]) for the catalysts under consideration were found to be: τ CPSM, fresh =4.6 and 4.5. These values are typical of porous catalysts and approach those determined experimentally (i.e. τ=5–6 [Appl. Catal. 10 (1996) 299]). The pore volume distribution of the latter catalyst obtained from mercury porosimetry measurements approaches that deduced by the CPSM method.

EVOLUTION LIGNITE MESOPORE STRUCTURE DURING DRYING. EFFECT OF TEMPERATURE AND HEATING TIME

The knowledge of the intrinsic pore structure of coals is significant in elucidating the kinetics of mass transport and chemical reaction that leads to design of more efficient coal combustion and conversion equipment. The results of pore structure studies of Greek lignite are reported in this work. Isothermal drying of Greek lignite samples, under vacuum, caused mesopore structure evolution despite the severe (∼50%) particle size contraction due to heating. Mesopore volume and surface area were increased as the drying temperature was raised to 200°C while further drying up to 250°C caused a mesopore volume and surface area decrease. Lignite drying at 100°C for up to 3 h resulted in a monotonic increase of the mesopore structure properties while heating for a longer period i.e., 6 h, despite a slight increase of weight loss, caused pore volume and surface area reduction. Nitrogen sorption (77 K) hysteresis data obtained for partially dried samples have been processed to deduce BET surface area and pore size distributions (PSD) by using both the Roberts and a new method based on a Corrugated Pore Structure Model (CPSM-nitrogen) methods. The latter method was applied successfully in hysteresis loop simulations and predicted pore surface areas consistent with the respective BET values. Bimodal PSD have been detected with one peak at 3 nm and the second at 20 nm while surface area varied over the range 2.98–5.30 m2/g. Dry Greek lignite has shown a higher mesopore volume than that of several American and Canadian coals of varying rank. Mesopore volume distribution of dry Greek lignite, obtained from nitrogen sorption data, agree well with those deduced from mercury penetration data corrected for coal compressibility.

A Novel Pore Structure Tortuosity Concept Based on Nitrogen Sorption Hysteresis Data

A corrugated pore structure model (CPSM−nitrogen)9 was employed to define a novel pore structure tortuosity concept. An empirical correlation is proposed for the prediction of tortuosity factors τCPSM as follows: τCPSM = 1 + A[(Dmax,eff − Dmin,eff)/Dmean](NS − 2)a. Constants A and a are adjustable parameters. The second factor reflects the influence of the intrinsic pore size distribution, and the third expresses the contribution of the nominal pore length parameter NS. The latter is, by definition, the number of pore segments forming a single corrugated pore of the CPSM pore configuration model and represents the frequency of pore cross section variation per unit length along a characteristic catalyst pellet dimension. The determination of NS and (Dmax,eff − Dmin,eff)/Dmean is accomplished by fitting the CPSM model over the pertinent nitrogen sorption hysteresis data. Coefficients A and a were found to be A = 0.69 and a = 0.58 by applying the empirical correlation for two specified materials of known to...

A New Model for Capillary Condensation−Evaporation Hysteresis Based on a Random Corrugated Pore Structure Concept: Prediction of Intrinsic Pore Size Distributions. 1. Model Formulation

The present article deals with the development of a new statistical model (corrugated pore structure model: CPSM) simulating capillary condensation−evaporation hysteresis. The formulation of analytical expressions is based on probability principles, an adsorbed layer thickness correlation, Kelvin equation, and a random corrugated pore concept. When the model is fitted over experimental hysteresis loop data, the respective intrinsic pore size distribution (psd) and the corrugated pore parameter, NS (frequency of pore cross-sectional area variation), can be determined. The predictive potential of the CPSM was successfully tested in part 1 (this work) by generating hysteresis loops that reproduced those included in the IUPAC classification as well as those of novel nanoporous MCM-41 materials. CPSM evaluations of intrinsic pore size distributions have been more realistic and accurate than those deduced by applying the conventional methods (e.g., Roberts). The model has been further tested successfully in part 2 (Ind. Eng. Chem. Res. 2000, 39, 3764) by the fitting of experimental hysteresis data of various porous materials, e.g., HDS catalysts, anodic oxide films, lignite, montmorillonite, pillared clays, and MCM-41 mesopore molecular sieves.

TOMOGRAPHY OF MACRO-MESO-PORE STRUCTURE BASED ON MERCURY POROSIMETRY HYSTERESIS

Mercury porosimetry (MP) hysteresis loop scanning (SHL) data are used in the deduction of pore structure tomography diagrams. Macro and/or meso-pore structure tomography refers to the tracing of intrinsic pore size distributions (psd) of pore structure sections corresponding to specified volume saturation levels. Tomography information may be proved a useful tool e.g., to elucidate mass transfer, heterogeneous reaction phenomena, eic. The contribution of the present work is the simulation of the MP - scanning data, based on the random corrugated pore structure model (CPSM), reported elsewhere and the generation of the pertinent pore structure tomography spectra (i.e., a set of local, as regards saturation, intrinsic psd). The CPSM model has been applied to carry out parametric studies for the generation of theoretical loop scanning diagrams and the construction of the pertinent tomography plots. Additionally the CPSM model have been successfully used in curve fitting applications by using experimental MP hysteresis loop scanning data, taken from literature or produced in this work, and the deduction of the respective tomography diagrams. Part 1 of this work is devoted to pore structure tomography accruing from MP loop scanning along the penetration line while Part II deals with loop scanning along the retraction curve and the derivation of the respective pore structure tomography spectrum. Overall, the CPSM model simulates satisfactorily MP loop scanning data and yields credible pore structure tomography information.

A SIMPLIFIED MODEL FOR MERCURY POROSIMETRY HYSTERESIS

A modified Random Corrugated Pore Structure Model (CPSM) simulating Mercury Porosimetry (MP) hysteresis and entrapment phenomena is proposed. The model have been applied in parametric sensitivity studies and data regression tests by using a single parameter Bell Shape Distribution (BSD) function as the intrinsic pore size distribution (psd). The new CPSM version proved to be superior compared to its original counterpart since it achieves a sensible evaluation of the trapped mercury distribution, enables the construction of a “closed” (zero entrapment) hysteresis loop and makes realistic predictions of the intrinsic pore volume and surface area distributions. CPSM predicted intrinsic psd's for reservoir sand stones compare satisfactorily with those measured independently by a photomicrography method. The model also provides the basis for the development of a least square computer code suitable for further improved psd calculations.