Stainless Steel Wire Mesh Packing Research Articles

Study of the Hydrodynamic Performance of a Compact and Intensified G/L Contactor: The RPB

Modern process equipment needed for safe and economically viable chemical and biological processes requires flexibility, compactness, and a great potential for enhancing mass transfer. Centrifugal process intensification equipment such as the rotating packed bed (RPB) satisfies the above mentioned requirements in addition to zero sensitivity to changes caused by gravity. The fundamental principles of RPBs are yet to be fully established due to difficulty in predicting their behavior which has necessitated the need for treating their design, modeling, and optimization on a case-to-case basis. This study focused on the hydrodynamics (pressure drops) of a pilot-scale RPB equipped with a stainless steel wire mesh packing. The effects of three operational parameters: average high gravity factor, integrated gas capacity factor, and liquid load, as well as a design parameter, the fluid distributor type were investigated. The maximum value of the average gravity factor used was 452. Also, a combined gas capacity factor of 2.6Pa0.5, and a liquid load of up to 20m3m-2h-1 were explored. Additionally, the influence of liquid distributor type on the pressure drop of RPBs was investigated.

Enhancement of devolatilization performance in a rotating packed bed with different packing structures

• The 3D-printed mesh packing with drop-shaped fibers (PMP-D) was manufactured. • The PMP-D was employed to enhance the devolatilization performance in RPB. • Compared with traditional SMP, the η and K L a of PMP-D was drastically improved. • Correlations to predict K L a were established with deviations less than ±20%. The devolatilization of volatile organic compounds (VOCs) from the viscous liquid like polymers was necessary but of great challenge caused by the high viscosity. In this work, different packing structures were manufactured in a rotating packed bed (RPB), including the stainless steel wire mesh packing (SMP), 3D-printed column packing (PCP), 3D-printed mesh packing with circular fibers (PMP-C), and 3D-printed mesh packing with drop-shaped fibers (PMP-D). The devolatilization performance of the RPB was investigated with the acetone-silicon oil working system. Results indicated that modifying the fiber shape of packing effectively intensified the devolatilization in the RPB. The removal efficiency ( η ) and volumetric mass transfer coefficient ( K L a ) of the PMP-D were dramatically larger than the other three packings. Compared the PMP-D with the traditional SMP, the maximum η was enhanced from 40% to 50%, and the increment of K L a was 50% on average. The correlations to predict K L a were established, and the deviations from the experimental results were less than ± 20%.

Wetting Behavior of the Stainless Steel Wire Mesh with Al2O3 Coatings and Mass Transfer Intensification in a Rotating Packed Bed

An Al2O3-coated stainless steel wire mesh packing was prepared, aiming to serve as the monolithic catalyst support applied in a rotating packed bed (RPB) reactor. Before the application, the wetting behavior and gas–liquid mass transfer performance of Al2O3-coated wire mesh packing were investigated in this work. The results showed that the Al2O3-coated stainless steel fiber had on average 18.8% longer liquid spreading length compared with the uncoated stainless steel fiber. The gas–liquid effective interfacial area (ae) and the volumetric liquid-side mass transfer coefficient (kLae) of the RPB with Al2O3-coated wire mesh packing were on average 25.9 and 45.7% higher than those with uncoated wire mesh packing, respectively. The Al2O3-coated wire mesh packing has great prospects for the catalytic reactions in the RPB reactor by providing double functions of mass transfer intensification and the monolithic catalyst support.

Mass transfer in a rotating packed bed reactor with a mesh-pin rotor: Modeling and experimental studies

A rotating packed bed (RPB) reactor with full stainless steel wire mesh packing loaded in the rotor has excellent mass transfer performance. However, it has the blockage problem when applied to the reactions with solid generated on the surface of the packing. In this work, a mesh-pin rotor (MPR), combining an inner wire mesh packing zone (IMZ) and an outer resin pin zone (OPZ), was designed with the purpose of anti-blockage for the first time, expecting to possess the high mass transfer performance of wire mesh packing and self-cleaning performance of cylindrical pins. With the assistance of liquid holdup measurement by X-Ray CT scan technology, a mass transfer model was proposed for the RPB reactor with MPR and the liquid-side volumetric mass transfer coefficient (kLae) was measured by using an oxygen-water desorption system. The predicted results by the model showed good agreement with the experimental results within a deviation of ±20%, displaying potential application prospects.

Controllable wettability on stainless steel substrates with highly stable coatings

A rotating packed bed (RPB) is one of the typical process intensification equipment and its performance can be influenced by the surface wettability of packings. However, tuning the surface wettability of the packing by the surface-modification method is still a challenge due to the extreme physical and chemical environment in RPBs. This work presents a facile strategy for controlling the surface wettability on the stainless steel substrate with a series of highly stable coatings. The water contact angles on the surfaces can be tuned from 75° to 160°. Based on the systematical analysis from the micro-characteristics (surface microstructure and surface free energy) to the macro-wettabilities (water contact angle) of the prepared coatings, the structure-function relationship of these coatings was revealed with wetting models. Application performance testing indicates that the coatings displayed strong adhesion, long-time corrosion resistance, and liquid impinging resistance under high-gravity conditions. This work opens a new avenue to produce highly stable coatings on stainless steel substrates with controllable wettability, which is very helpful to the wettability control for the stainless steel wire mesh packing of RPBs for industrial applications.

Investigation of micromixing and precipitation process in a rotating packed bed reactor with PTFE packing

A rotating packed bed (RPB) reactor plays an important role in process intensification of micromixing and mass transfer. However, the commonly used stainless steel wire mesh packing suffers from serious corrosion in various chemical processes. Polytetrafluoroethylene (PTFE) material, which is well-known for its excellent anticorrosion property, was employed as packing in the RPB reactor. Micromixing efficiency of the RPB reactor with PTFE packing was studied experimentally by adopting the iodide-iodate reaction system. Results showed that the micromixing efficiency of the RPB reactor with PTFE packing was better than that with the conventional stainless steel wire mesh packing. The micromixing time (tm) was calculated using an incorporation model based on the experimental data. Furthermore, the RPB reactor with PTFE packing was applied to a precipitation process for the preparation of magnesium hydroxide (Mg(OH)2) nanoparticles. The obtained Mg(OH)2 nanoparticles have small size and narrow particle size distribution, which indicates that the RPB reactor with PTFE packing is a promising reactor for preparing small size nanoparticles with its excellent micromixing efficiency.

3D numerical simulation of a rotating packed bed with structured stainless steel wire mesh packing

Computational fluid dynamics (CFD) is a powerful tool used to investigate the hydrodynamics in various chemical devices. As one of the typical process intensification equipment, rotating packed beds (RPBs) have been widely used in various fields. However, it is still a challenge to obtain the detailed information by CFD analysis due to the complex packing structure in the rotor of a RPB. In this study, we firstly built a three dimensional (3D) physical model with the same structure and size as the physical RPB and structured stainless steel wire mesh packing. The realizable k-ε model is applied to investigate the gas pressure drop, pressure distribution, and gas flow at different rotational speeds and gas flow rates. Based on the breakdown of the overall gas pressure drop, the gas pressure drop in the inner cavity zone is the major contributor to the overall gas pressure drop under most operation conditions. The 3D physical model describing the actual RPB can give deep understanding of the gas flow in the entire RPB as well as the gas flow behavior around every fiber of the packing. Furthermore, one special phenomenon of strong turbulence, named as gas-side end effect, was revealed in the outer annular packing zone in the rotor.

Polytetrafluoroethylene Wire Mesh Packing in a Rotating Packed Bed: Mass-Transfer Studies

Polytetrafluoroethylene (PTFE) material, which is well-known for its excellent anticorrosion properties, was used as wire mesh packing in a rotating packed bed (RPB). The effective interfacial area (ae) and the volumetric liquid-side mass-transfer coefficient (kLae) of the RPB with PTFE packing was studied experimentally by a NaOH–CO2 chemical absorption system and an oxygen–water physical desorption system, respectively. Experimental results showed that both ae and kLae increased with decreasing fiber diameter and pore size. As for material, mass-transfer performance of the PTFE packing was lower than that of the stainless steel wire mesh packing but is applicable in some high-corrosion and -viscosity environments. Moreover, correlations for ae and kLae were proposed.

Investigation of effective interfacial area in a rotating packed bed with structured stainless steel wire mesh packing

Packing plays an important role on the mass transfer and mixing in a rotating packed bed (RPB) which is regarded as an important gas-liquid reactor or contactor for process intensification. Stainless steel wire mesh packing exhibits good mass transfer performance when applied in a RPB. However, its construction repeatability and mechanical strength should be improved. Therefore, we introduced and designed a novel structured stainless steel wire mesh packing, aiming to overcome the above problems. In this work, the effective interfacial area (ae) in the packing and cavity zones of a RPB with four different types of structured stainless steel wire mesh packings was investigated at various rotational speeds, gas flow rates, and liquid flow rates by using a NaOH-CO2 mass transfer system. A brief analysis of the gas-liquid mass transfer interface area (A) and utilization ratio of packing’s specific surface area (wp) is presented. A modified correlation for the effective interfacial area in the packing zone of the RPB with structured stainless steel wire mesh packing was also proposed, and the predicted values were found to be in agreement with the experimental values with deviations generally within ±15%.

Micromixing Efficiency Enhancement in a Rotating Packed Bed Reactor with Surface-Modified Nickel Foam Packing

Micromixing, the mixing at the molecular scale, is believed to play a substantial role in many industrial processes. In this work, a novel surface-modified nickel foam packing (SNP) loaded in a rotating packed bed (RPB) reactor was first proposed to improve the micromixing efficiency studied by adopting the iodide–iodate reaction as a working system. Experimental results showed that the RPB reactor with the SNP presented better micromixing efficiency, compared to the RPB reactor with the nonmodified nickel foam packing (NNP) or traditional stainless steel wire mesh packing (SWP). It could be found that the segregation index (XS) decreased as the rotational speed and liquid flow rate each increased, while it increased with increasing acid concentration and volumetric ratio. Moreover, the micromixing time (tm) was calculated using an incorporation model based on the experimental data. Compared with NNP or SWP, the minimum tm value of SNP (tm = 3.28 ms) is less than that of NNP (tm = 5.68 ms) or SWP (tm = 8....

Gas–Liquid Effective Interfacial Area in a Rotating Packed Bed

Stainless steel wire mesh packing is widely used for experimental and industrial applications in rotating packed beds (RPBs) for gas–liquid contacting because it has a higher mass-transfer performance than other conventional packings. In this work, the gas–liquid effective interfacial area of a conventional RPB was studied with eight types of stainless steel wire mesh packings, consisting of four different stainless steel fibers. Gas–liquid chemisorption with CO2 in NaOH solution was employed to measure the effective interfacial area for all types of packings with different rotational speeds and gas–liquid ratios. An empirical correlation that takes the effects of the fiber diameter and opening size of the wire mesh into consideration was proposed for the calculation of the gas–liquid effective interfacial area of stainless steel wire mesh packings in a conventional RPB.

Study on hydrodynamic performance and mass transfer efficiency of nickel foam packing

The features of nickel foam packing were introduced. The hydrodynamic performance and mass transfer efficiency of nickel foam packing were measured and a mass transfer equation was established to predict the HETP results. Comparing with CDG1700X stainless steel wire mesh packing, nickel foam packing has better hydrodynamic performance and mass transfer efficiency, the mass transfer efficiency is 40% higher than the CDG1700X stainless steel wire mesh packing, and pressure drop is 20% of the CDG1700X stainless steel wire mesh packing.

An experimental and theoretical investigation into the hyperbolic nature of axial dispersion in packed beds

The concept of hyperbolic axial dispersion of heat in a flowing fluid which is known as `third sound wave' has been examined taking packed bed as an example. This technique analyse fluid flow and heat transfer by introducing an axial dispersion term in the one-dimensional energy equation to take care of flow maldistribution and backmixing. The present approach models this dispersion in terms of two parameters which are proposed to follow hyperbolic conduction law. A regenerator bed consisting of stainless steel wire mesh packing has been used to carry out experiments for the purpose of validating the concept. The analytical model presented uses a Laplace transform technique for the solution of simplified energy equation. The computed outlet fluid temperature is compared with experimental output and the two model parameters, dispersive Peclet number ( Pe) and its propagation velocity ( c *) are estimated. The present model, the parabolic (Fourier) dispersion model and the non-dispersive plug flow model are compared with the experimental result which brings out the closeness of the present proposition to reality compared to other models. A standard experimental technique is suggested which can be used for the measurement of parameters related to axial dispersion. The present study is the first experimental evidence of `third sound wave' in fluids and lays foundation of this proposition.

HOLDUP MEASUREMENT IN A SCHEIBEL EXTRACTION COLUMN

Abstract ABSTRACT The total holdup of a dispersed organic phase in a rotary-agitated Scheibel liquid-liquid extraction column of the first type is studied experimentally. The column is 2 inches in diameter and contains 11 stages with a 4-inch height packed section and a 1-inch height mixing section. The packed section is made of stainless steel wire mesh packing with a 93.74% free area and acts as a settler for the coalescence of droplets. Three systems are studied: benzene/water, methyl isobutyl ketone (MIBK)/water and 20% TBP-80% kerosene/1 M nitric acid. The effects of different phase flow rates and rotation speeds (300-670 rpm) on the dispersed phase holdup are investigated. The results show that the holdup increases with increasing dispersed phase flow rate but does not vary with continuous phase flow rate. For benzene, the holdup is large at low rotation speeds and decreases with increasing rotation speed until a minimum holdup is reached, after this transition point, the holdup increases with incre...