Modeling of the Effects of Pleat Packing Density and Cartridge Geometry on the Performance of Pleated Membrane Filters

Pleated membrane filters are widely used to remove undesired impurities from a fluid in many applications. A filter membrane is sandwiched between porous support layers and then pleated and packed into an annular cylindrical cartridge with a central hollow duct for outflow. Although this arrangement offers a high surface filtration area to volume ratio, the filter performance is not as efficient as those of equivalent flat filters. In this paper, we use asymptotic methods to simplify the flow throughout the cartridge to systematically investigate how the number of pleats or pleat packing density affects the performance of the pleated membrane filters. The model is used to determine an optimal number of pleats in order to achieve a particular optimum filtration performance. Our findings show that only the “just right”—neither too few nor too many—number of pleats gives optimum performance in a pleated filter cartridge.

Hybrid Sand Control Screen Using the Combined Surface and Depth Filtration

Development of weakly and unconsolidated sand reservoirs require effective sand control media to prevent sand production. The existing sand control devices in the market are either relying on surface filtration to prevent sand production through size exclusion or bridging or depth filtration which relies on the pore size distribution of a porous filter or pack to prevent the sand from producing along the production fluids. In this study, we introduce a new hybrid sand screen that works based on a combined surface and depth filtration. Radial Sand Control Evaluation (RSCE) testing facility was used to compare the solid production and flow performance of the new hybrid screen with various mesh media in multi-phase gas and liquid flow under various fluid injection scenarios. Solid production and flow performance were compared with investigated cases. The new hybrid screen provides an optimized Open to Flow Area (OFA) in comparison to available surface filtration or depth filtration media, which provides required OFA, while prevents sanding. The robust design, low cost and manufacturing ease make it a suitable screen media for most sand control applications. The sand retention test results under various fluid injection scenarios including multi-phase oil, brine, and gas show that it outperforms the Dutch Twill (DT) weave and Reverse Dutch Twill (RDT) weave of equivalent aperture size, with better flow performance at constant flow rate tests compare to best-performing mesh media, while keeping the produced sand far below the acceptable thresholds. Hybrid design handles both high velocity and high Gas-Oil Ratio (GOR) better than equivalent depth filtration media of equivalent size. This paper presents a detailed characterization, flow performance testing of a new hybrid sand control media that combines the surface filtration and depth filtration properties to achieve better solid retention and flow performance. The hybrid screen media is suitable for high-rate producers with high GOR. Keywords: Hybrid Screen, Surface Filtration, Depth Filtration, Radial Sand Control Evaluation (RSCE) Testing

Research Analysis and Construction of Application of Deep Filtration Technology in Biopharmaceutical Process

This article analyzes the difference between deep filtration technology and surface filtration technology. The author studied the specific application of deep filtration technology in clarification of fermentation broth, pyrogen removal filtration, small molecule purification, product purification and separation, and purification of macromolecules. This article analyzes the common problems during the application of deep filtration technology. The author puts forward suggestions to improve the resource sharing mechanism, standardize the management of filtering research institutions, increase research on new technologies, and do a good job of comprehensive training of personnel. The purpose of this article is to deepen people’s understanding of deep filtration technology and promote the healthy economic development of the biopharmaceutical industry.

Study on the Filtration Performance of the Baghouse Filters for Ultra-Low Emission as a Function of Filter Pore Size and Fiber Diameter

The main objective of this study was to determine the effect of filter pore size and fiber diameter on the performance of the baghouse filters for ultra-low emission. In this study, three kinds of conventional polyester filter (depth filtration media) and two kinds of polytetrafluoroethylene membrane-coated polyester filter (surface filtration media), having various filter pore sizes and fiber diameters, were tested to determine the performance of static and dynamic filtration. In order to determine the static filtration performance, the filtration resistance and the filtration efficiency of the clean filter media were measured by the arrestance method. The dynamic filtration performance experiments were conducted to determine the dynamic resistances, dust depositions, and dynamic filtration efficiencies of the dust-containing filter media under the condition of dust airflow filtration through a pulse-cleaning cycle. In the dynamic filtration performance experiments, the size of 50% test dust was less than 2.5 μm, and the mass mean aerodynamic diameter of the dust was 1.5 μm. The filtration velocity was 2 m∙min−1, and the dust concentration was 18.4 g∙m−3. The static filtration performance experiments showed that the filter pore size greatly affected the filtration resistance and the filtration efficiency of the fabric structure of the surface filtration media. In the depth filtration media, the filtration efficiency and the filtration resistance of the fabric structure were improved when the filter pore size and the fiber diameter were smaller in magnitude. For all the five filter media, smaller the pore size of the filter media, greater was the filtration precision (for fine particles, such as PM2.5) of the fabric structure. In the dynamic filtration performance experiments, the filter pore size and the fiber diameter of the depth filtration media affected the dynamic filtration resistance and the dynamic filtration efficiency of the depth filtration media by affecting the deposition rate of dust in the depth filtration media; however, the filter pore size of the surface filtration media affected the blocking rate of dust in the membrane micropores, thus influencing the dynamic filtration resistance and the dynamic filtration efficiency of the surface filtration media.