Characterisation of porous solids by simplified gas relative permeability measurements

A novel design for the application of a simplified experimental procedure, capable of providing satisfactory relative permeability data for porous media at low relative pressures, is presented. The technique avoids the two-component mixing complications as well as the problems arising from the sample macroscopic inhomogeneity. The latter has been reduced with the aid of a variable pressure compaction procedure. Thus, it becomes easier to utilise the powerful relative permeability technique for the characterisation of the structure of porous solids. Emphasis is given to the combination of the relative permeability data obtained with an analytical approach based on Effective Medium Theory for the calculation of pore connectivity.     

天然气水合物沉积层渗流特性的模拟

天然气水合物开采过程中水合物饱和度的变化会引起储层渗透率的相应变化,对开采过程造成影响。为研究天然气水合物对多孔介质渗流特性的影响,本文基于孔隙网络模型模拟研究了水合物生成于壁面与中心两种方式下,多孔介质渗流特性变化,并与相关模型进行比较。结果表明,水合物生成于中心时绝对渗透率小于生成于壁面时;水合物饱和度相同时多孔介质孔径越大,渗透率越大;水合物生成于中心时两相相对渗透率等渗点小于生成于壁面时;当水合物饱和度变化时两相相对渗透率几乎不变。说明了储层渗透率与水合物饱和度之间有相对应的关系。     

Scale-up of functional properties of pressure-sensitive adhesive from laboratory to industrial plant production: from monomers to label

A waterborne acrylic pressure-sensitive adhesive produced in a commercial plant to label market was successfully developed. In order to reach the required functional properties (i.e. holding time, peel, and loop tack strengths), glass transition temperature, functional monomer content, type of surfactant, and reaction temperature were optimized. A proper balance of wetting and thickening agents content was found taking into consideration their significant unfavorable effect on functional properties.     

基于RBF神经网络的油藏相对渗透率曲线计算

提出了一种基于改进的RBF神经网络的相对渗透率曲线计算方法。利用骨干粒子群的位置更新操作更新RNA遗传算法的变异算子得到混合RNA遗传算法（HRGA）,针对RBF神经网络中隐含层径向基中心值的确定,利用HRGA算法对其进行优化,并用于相对渗透率曲线的计算。将HRGA优化的RBF神经网络和标准RBF神经网络计算的相对渗透率曲线与真实值误差对比分析,实验结果表明HRGA优化的RBF神经网络明显提高了计算精度。     

溶液型选择性堵水剂的研究现状

溶液型选择性堵水剂(RPM)能够选择性的降低油井中水相的渗透率,对油相影响很小,目前国内外对其研究比较活跃,作者介绍了RPM的堵水机理,列举了国内外的研究状况,阐述了RPM的选择性堵水能力的评价方法,指出了RPM的发展趋势。     

Modeling drying in thin porous media after coupling pore-level drying dynamics with external flow field

This article uses a novel, fully coupled method to solve the isothermal slow drying of porous media in laminar flow. The film effect is included and a novel logistic equation is used to relate the pore network variables with the external field variables. The model is used to simulate the drying of several thin porous media with different aspect ratios in a flow. One, two, or all sides of the pore network are opened to the flow. The studies show that the higher exposed area vs. total volume ratio leads to faster drying while the orientation of the porous media is immaterial.     

A method to calculate the multiphase flow properties of heterogeneous porous media by using network simulations

A method is suggested to compute the capillary pressure and relative permeability curves of heterogeneous porous media. The broad pore radius distribution (PRD) and throat radius distribution (TRD) are decomposed into relatively narrow component distribution functions which are used for the computer‐aided construction of pore‐and‐throat networks. The quasi‐static motion of menisci in pores and throats is tracked by accounting for capillary forces. The presence of fractal roughness along pore walls ensures the coexistence of both phases in pores. The calculation of the hydraulic conductance of each phase is based on the concept of constricted unit cell. Simulations in component pore networks constructed from narrow PRD and TRD produce a set of capillary pressure and relative permeability functions, the arithmetic averaging of which yields the corresponding functions for a heterogeneous synthetic pore network. This information is used by a dynamic simulator of drainage in permeability networks to predict experimental results of soil columns. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

Evaluation of the polymer hydrogels as a potential relative permeability modifier

Excessive water production poses a significant challenge in the oil industry, especially in Pre-salt carbonate reservoirs, leading to reduced oil recovery, corrosion, and well abandonment. We explore the potential of polymeric preformed particle gels (PPGs) as innovative relative permeability modifiers (RPMs) for carbonate reservoirs. RPMs involve applying polymeric hydrogels to alter reservoir wettability, reducing water flow while enhancing oil productivity. PPGs offer a promising surface-based production alternative with improved control and minimized formation damage compared to traditional in-situ gels. We conducted crosslinking experiments using poly(acrylamide-acrylic acid-2-methyl propane sulfonate) terpolymer (AM-AA-AMPS) and aluminum (III) ions, assessing their impact on hydrogel properties. We also investigated the swelling behavior of these hydrogels and their interactions with rock samples. Results showed that crosslinking significantly affects PPG viscoelastic properties and swelling behavior. Adsorption tests revealed the formation of a polymeric film on rock surfaces, potentially altering wettability. Contact angle measurements demonstrated PPGs' ability to shift rock wettability, particularly in carbonate samples, from strongly oil-wet to water-wet conditions. This study underscores PPGs' potential as RPMs, offering valuable insights into improving oil extraction efficiency and addressing water production challenges in the industry.     

往复振动筛板萃取塔放的大设计模型

对往复振动筛板萃取塔（RPEC）塔内的传质过程进行了理论分析，并在此基础上，从单液滴传质模型出发，应用数学统计方法建立了RPEC放大设计模型，即进行放大设计时应遵循通量、塔板间距、振幅和频率不变的原则计算表观传质单元高度H_OXP.采用林可霉素-正丁醇-酸水物系对塔径100 mm的RPEC实验塔研究表明：真实传质单元高度H_OX与体系物性、表观速度、输入能量（振幅A×频率f）有关，而与塔径无关，且不受轴向混合的影响，模型较好地预测了H_OX随输入能量的增加而减小，而通量的变化则对其影响较小;分散传质单元高度H_OXD是塔径D、输入能量、通量U_s和体系物性的函数，实验结果表明模型较好地描述了输入能量和通量增加强化传质起主导作用，有效降低分散传质单元高度H_OXD的传质过程部分，而不能描述轴向混合起主导作用部分.应用放大设计模型对直径325 mm的RPEC放大设计结果验证模型的预测误差在20％以内.     

Evolution of coal permeability from stress-controlled to displacement-controlled swelling conditions

When a coal sample is constrained either by displacements or by a confining stress, additional force and resulting stress develop within the coal. A simple “free expansion + push back” approach is developed in this work to determine the magnitude of this stress and its effect on permeability evolution. In this approach, the coal is allowed to expand freely due to gas sorption, and then it is pushed back by the applied effective stress to the original constrained conditions. The total “push-back” strains are used to calculate the change in coal permeability. This free expansion plus push back approach is applied to examine the variety of permeability responses observed in the laboratory and the veracity of their representation by theoretical models linking this behavior to gas sorption-induced swelling/shrinkage. These cases include (1) coal swelling tests under the uniaxial strain condition; (2) coal swelling tests under the displacement controlled condition; (3) coal swelling tests under the stress controlled condition. These responses are verified against other coal permeability models available in the literature and against experimental data and field data where few analytical solutions are currently available. In particular, this approach has led to a new coal permeability model that can be used to explain stress-controlled experimental observations. Stress-controlled swelling tests are normally conducted in the laboratory to characterize the evolution of coal permeability under the influence of gas sorption. Typically reductions in permeability are observed from gas-sorption-induced swelling even where effective stresses remain constant. This behavior remains enigmatic as the permeability of the porous coal is determined by the effective stress only. Our model is capable of replicating this apparently anomalous behavior.     

Simulated Scale-up and Cost Estimate of a Process for Alkaline Isomerization of Lactose to Lactulose Using Boric Acid as Complexation Agent

A continuous pilot plant process for converting lactose to lactulose, using boric acid as a complexation agent was previously developed. To appraise the commercial feasibility of the process, a scale-up to a commercial plant using the ERRC Food Process Simulator, a process simulator developed at the Eastern Regional Research Center was projected and a cost estimate made. The cost to produce a 55% lactulose syrup at a rate of 93 kilograms per hour (563359 kg year⁻¹) was $5.20 per kilogram ($2.36 per pound). These costs, which do not include packaging or distribution expenses, do include a 25% return on the plant investment. © 1997 SCI.     

Intrinsic permeability of refractories from gas permeability measurements: Comparison of results

The gas permeability of porous materials largely depends on pressure, with the intrinsic permeability typically being determined using Klinkenberg's model, which is valid when the gas flows under viscous conditions. However, measurements performed on refractories with the outlet at atmospheric pressure often reveal inertial effects. Therefore, gas permeability is assumed to be flow-rate dependent; an alternative approach is proposed to determine the intrinsic properties using the Forchheimer number. A gas permeameter has been developed to improve measurement accuracy. It allows for the conduction of a test in viscous flow conditions or with inertial effects. The improved gas permeameter was used to compare the different approaches to the evaluation of the intrinsic permeability of four refractory materials with permeabilities ranging from 0.03 to 6 darcies. Combining a modified pressure drop method with Klinkenberg's model proved to be a reliable method for consistently evaluating refractory material permeability.     

Enhancement of the relative magnetic permeability of polymeric composites with hybrid particulate fillers

Composites with high relative magnetic permeability values can be used in many industrial applications, especially if they can be shaped using conventional polymer-processing technologies. In this study, various hybrid composite systems (i.e., particles with differing aspect ratio, size, and magnetic permeability embedded into a polymeric binder) were prepared in an attempt to reach high relative permeability values without the use of high pressures or sintering. It was determined that an interaction effect between the different types of fillers exists and enhances the relative magnetic permeability value of the composite in relation to the use of single type of magnetic filler. Relative magnetic permeability values of over 100 were achieved. Such relative magnetic permeability values represent a significant increase in the magnetic permeability over available magnetic composites prepared using similar processing techniques. The significant gains in magnetic permeability were realized by altering the maximum packing fraction, and ultimately the percolation threshold of the composite, by using low and high aspect ratio particles simultaneously in the formulation of the magnetic composites. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 1371–1377, 1997     

草酸电解还原制备乙醛酸的放大研究

中试电解槽中采用了双面电极板和湍流器 ,实现了电解液的均匀分布和电流的均匀分布。当电解槽的长宽比为 1.7∶1 0、电解液流速为 0 .139m/s时 ,电流效率为 84.82 %、乙醛酸的选择性为 93.4%。而在相同的电流密度和电解温度下 ,当小试电解液流速为 1.0m/s时 ,电流效率为 84.2 7%、乙醛酸的选择性为 86 .76 % ,放大效应接近 1.0。     

Pore network modeling of catalyst deactivation by coking,from single site to particle,during propane dehydrogenation

A versatile pore network model is used to study deactivation by coking in a single catalyst particle. This approach allows to gain detailed insights into the progression of deactivation from active site, to pore, and to particle—providing valuable information for catalyst design. The model is applied to investigate deactivation by coking during propane dehydrogenation in a Pt-Sn/Al₂O₃ catalyst particle. We find that the deactivation process can be separated into two stages when there exist severe diffusion limitation and pore blockage, and the toxicity of coke formed in the later stage is much stronger than of coke formed in the early stage. The reaction temperature and composition change the coking rate and apparent reaction rate, informed by the kinetics, but, remarkably, they do not change the capacity for a catalyst particle to accommodate coke. Conversely, the pore network structure significantly affects the capacity to contain coke. © 2018 The Authors. AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers. AIChE J, 65: 140–150, 2019     

A model for stress-dependence of apparent permeability in nanopores of shale gas reservoirs

Predicting long-term production from gas shale reservoirs is a challenging task due to changes in effective stress and permeability during gas production. Unlike coal, the variation of sorbing gas permeability with pore pressure in shale does not always feature a biphasic trend under a constant confining pressure. The present contribution demonstrates that the biphasic dependence of permeability on pore pressure depends on a number of physical and geometrical factors, each with a distinct impact on gas permeability. This includes pore size, adsorption isotherm, and the variation of gas viscosity with pore pressure. A single-capillary model is proposed for the apparent permeability of real gas in shale. Results indicate that the biphasic relation between apparent permeability and pore pressure is prevalent when the sorbing gas flows in sufficiently small pores. In addition, the effects of sorption isotherm and internal resistance of nonideal gas to flow cannot be ignored.     

Reverse Micellar Extraction of Bromelain from Pineapple (Ananas comosus L. Merryl) Waste: Scale-up,Reverse Micelles Characterization and Mass Transfer Studies

Scale-up studies for phase transfer mode of reverse micellar extraction are attempted for the separation and primary purification of bromelain (EC 3.4.22.33) from pineapple (Ananas comosus L. Merryl) waste. Characterization of reverse micelles and mass transfer studies for the real system has been attempted for the first time. Scale-up of the extraction process employing commercial grade surfactant cetyltrimethylammonium bromide (CTAB) and solvent isooctane resulted in purification of 2.43 fold with an activity recovery 81.3%. The reverse micellar size estimated using empirical and geometrical models indicated that the reverse micelles are large enough (R_m = 7.2–9.6 nm) to host bromelain molecules that are relatively smaller in size (～1.67 nm). The studies on the kinetics of mass transfer indicated a relatively slower rate (by ～34%) of mass transfer in case of back extraction compared to forward extraction. Process scale-up did not significantly affect the extraction efficiency whereas purity of phase components played a major role. The mass transfer across the phases was high in the initial period of mixing for both forward and back extractions.     

超滤膜用于低渗透油田清水注水处理

针对吉林油田黑98站清水注水过程中所存在的SS严重超标、阻垢剂投加量过大等问题,采用了内压式中空纤维超滤工艺对低渗透油田清水注水进行处理.通过与精细过滤工艺的对比,介绍了内压式中空纤维超滤工艺的特点、运行情况.运行结果表明:在工艺进水SS均值为4.4 mg/L时,出水SS均值0.218 mg/L,满足《碎屑岩油藏注水水质推荐指标及分析方法》(SY/T 5329-1994)中的A1级别;滤膜出水中阻垢剂最佳值为30 mg/L,每年节省药剂费24万元.