Wire Mesh Mist Eliminator Research Articles

Capacity and Sizing of Wire Mesh Mist Eliminators at Critical Fluid Properties

AbstractWire mesh flooding point measurements at low surface tension < 10 mN m−1 were conducted using a refrigerant as model fluid. A new method for the calculation of wire mesh capacity was developed based on experimental data from literature and data from this study. In comparison to the well‐known and widely adapted K‐value method given in the Gas Processors Suppliers Association (GPSA) Engineering Databook and various other sources, the new method yields 3–38 % reduced wire mesh cross sections for fluid systems at pressures above 20 bar(a) while retaining an inherent safety margin.

Numerical study of performance of wire mesh mist eliminator

In this paper the effects of geometry and operating conditions on the pressure drop and separation efficiency of wire mesh mist eliminator have been investigated numerically. The effects of various variables such as vapor velocity (1–20 m/s), packing density (100–250 kg/m3), demister thickness (300–200 cm), wire diameter (0.1–0.3 mm), diameter of captured droplets (1–3 mm) and the geometry of wires on droplet separation efficiency and vapor pressure drop of demister have been studied in order to evaluate the demister performance. The results show the increase of separation efficiency with increasing the diameter of water droplets, vapor velocity, packing thickness and density while increasing wire diameter decreases the performance.

Numerical simulation of vapor flow and pressure drop across the demister of MSF desalination plant

This paper presents a numerical simulation of the water vapor flow in an MSF flash chamber along with the pressure drop across the demister. The demister is a simple porous blanket of metal wires mesh (usually made of stainless steel wires) which retains liquid droplets entrained by the vapor momentum to enhance the quality of the product water. Two main areas of concern in wire mesh mist eliminators are; (i) the pressure drop and (ii) the mist removal efficiency. The present simulation focuses only on the pressure drop across the demister. The simulation is carried out considering a full scale flashing chamber of a typical operational MSF desalination plant and of a real industrial demister dimensions. The study simulates the demister as porous media flow. It takes into account the vapor velocity, the dimension of the demister, its porosity and wire thickness. The obtained pressure drop was found to be within a reasonable agreement with the published literature data and it follows a trend compatible with Ergun’s equation as well as the empirical correlation of Svendsen.

Investigating pressure drop across wire mesh mist eliminators in bubble column

Effects of design parameters on pressure drop across the wire mesh mist eliminators were experimentally investigated in 15cm bubble column. The pressure drop across the demister pad was evaluated as a function of wide ranges of operating and design parameters. These parameters include: specific surface area (236–868m2/m3), void fraction (97–99%), wire diameter (0.14–0.28mm), packing density (130–240kg/m3), and superficial gas velocity (0.109–0.118m/s). All demisters were 15cm in diameter with 10cm pad thickness, made from 316L stainless steel layered type. Experiments were carried out using air–water system at ambient temperature and atmospheric pressure. The measurements of the pressure drop were done using a U-tube manometer device. The pressure drop across the demister pad is a combination of dry and wet pressure drops. In this work, the experimental investigations showed that the dry pressure drop is nil. The wet pressure drop was found to increase with increasing the demister specific surface area, packing density, and superficial gas velocity. In contrast, it was found to increase with decreasing the demister void fraction and wire diameter. The pressure drop is correlated empirically as a function of the design parameters. A good agreement was obtained between the measured values and the correlation predictions with ±15% accuracy.

Simplification Model for Prediction of Pressure Drop in Wire Mesh Mist Eliminator by CFD

In this article, computational fluid dynamics(CFD) method is used to predict the pressure drop of a wire mesh mist eliminator. A simplification method is used during the simulation process to solve the difficulty of model building during the simulation of the mist pad. A two-dimensional model is employed to acquire the resistance of mesh pad with different layer spacing. The flow field is calculated using 2D Reynolds-averaged Navier-Stokes equations. turbulence model is used to simulate the Reynold stress. And pressure drop of wire mesh mist eliminator is expressed as a function of broad ranges of inlet velocity. After CFD simulation, model experiment study is carried on using a small scale wind-tunnel. The pressure drop is gained to testify the numerical simulation result.

Investigating droplet separation efficiency in wire-mesh mist eliminators in bubble column

Effects of design parameters on performance of wire-mesh mist eliminators were experimentally investigated in 15cm bubble column. The demisters performances were evaluated by droplet collection efficiency as a function of wide ranges of operating and design parameters. These parameters include: droplet size exiting the demister (250–380μm), specific surface area (236–868m2/m3), void fraction (97–98.3%), wire diameter (0.14–0.28mm), packing density (130–240kg/m3), and superficial gas velocity (0.109–0.118m/s. All demisters were 15cm in diameter with 10cm pad thickness, made from 316L stainless steel layered type demister pad wires. Experiments were carried out using air–water system at ambient temperature and atmospheric pressure. The experimental data on the droplet removal efficiency were obtained using Malvern Laser Droplet Sizer. The removal efficiency was found to increase with the increasing the demister specific surface area, packing density, and superficial gas velocity. In contrast, the removal efficiency was found to increase with decreasing the demister void fraction and wire diameter. The separation efficiency is correlated empirically as a function of the design parameters. A good agreement was obtained between the measured values and the correlation predictions with ±5% accuracy.

Determination of pressure drop in wire mesh mist eliminator by CFD

With this article, pressure drop was predicted in a mist pad by CFD and compared with the available experimental data and empirical model. A CFD study was made to determine the pressure drop of wire mesh mist eliminator as a function of broad ranges of inlet velocity 1–7 m/s. The simulation was carried out in an industrial scale layered type demister pad made of stainless steel wires. These variables were measured as a function of vapor velocity (1–7 m/s), packing density (200 kg/m 3), pad thickness (200 mm), wire diameter (0.31 mm) and distance between mesh wires of (5 mm). The numerical solutions were carried out using spreadsheet and commercial CFD code FLUENT 6.0. The CFD simulations predict excellently the wire mesh mist eliminator pressure drop under inlet velocity with a maximum deviation of 14% from the Frashband's refinery data and 21% from empirical formula. The efficiency of the demister is at highest at the gas inlet velocity of 6 m/s.

Conventional and Complex Knitted Mesh Mist Eliminators

Knitted wire mesh mist eliminators have a widespread application in many industrial plants as they assure an optimum cost/performance for many applications compared with other separation devices. Complex mesh pads allow the performance and the range of applications of conventional wire mesh pads to be extended. In recent years, increasing research effort has been dedicated to the experimental investigation of both common and complex mesh pads and to the development of reliable design models that are essential for the design and optimization of complex separation units.

Performance of wire mesh mist eliminator

An experimental study was made to measure the performance of wire mesh mist eliminator as a function of broad ranges of operating and design conditions. The experiments were carried out in an industrial scale layered type demister pad made of 316 L stainless steel wires. The demister performance was evaluated by droplet separation efficiency, vapor pressure drop of wet demister, and flooding and loading velocities. These variables were measured as a function of vapor velocity (0.98–7.5 m/s), packing density (80.317–208.16 kg/m 3), pad thickness (100–200 cm), wire diameter (0.2–0.32 mm), and diameter of captured droplets (1–5 mm). All the measurement results lie in ranges where, in practice, the wire mesh mist eliminator predominates. The experimental results indicate that the separation efficiency increases with both the maximum diameter of capture water droplets and the vapor velocity and with the decrease of wire diameter. The pressure drop for the dry demister is relatively low and depends only on the vapor velocity. The pressure drop increases linearly up to the loading point, thereafter; the rate of increase is larger. Beyond the flooding point, the increase rate is significant even for the slightest rise in the vapor velocity. The flooding velocity diminishes with the beef-up of the packing density and with the decrease of the wire diameter. Three empirical correlations were developed as a function of the design and operating parameters for the separation efficiency, pressure drop for the wet demister in the loading range, and the flooding and loading velocities. These correlations are sufficiently accurate for practical calculations and demister design. The temperature depression corresponding to the pressure drop in a wire mesh mist eliminator systems installed in a typical multi stage flash desalination plant was estimated from the developed correlation. A good agreement was obtained between the design values and the correlation predictions.

Design of wire mesh mist eliminators

AbstractKnitted wire mesh mist eliminators are used extensively in many industrial plants. Their widespread application is essentially due to the low cost and efficient removal of entrained liquid droplets from vapor and gas streams. Despite the broad range of entrainment removal applications, open literature on this topic is limited. All the available design relations are based on semiempirical equations with an uncertain range of application. In this work, a set of new experimental data was obtained by investigating the performances of commercial eliminators, and a mechanistic model is presented. Comparison between experimental data and the proposed model shows that it can be used to predict separation efficiency both for horizontal and vertical arrangements.

水平流エリミネーターのミスト捕集性能に関する実験的研究

When a mist eliminator is installed in horizontal-flow, collected liquid on the eliminator flows down easily by gravity. In a horizontal-flow, therefore, it is expected that pressure drop across the eliminator is lower and gas velocity at a re-entrainment point is higher than those in an up-flow.In this paper, experimental work was carried out on pressure drop across the eliminator and collection efficiency of the eliminator for water mist in a horizontal-flow.Expanded metal and three kinds of wire mesh mist eliminators which are commercially available were used as a mist eliminator. Experimental results are compared with the results of York et al. in an up-flow. In a horizontal-flow, pressure drop across the eliminator was lower and gas velocity at the re-entrainment point was higher than those in the up-flow under same test conditions. Experimental collection efficiencies are considerably lower than those of theoretical calculation. This reason is considered that water droplets impinged on the eliminator were ruptured to fine mists which were too fine to be collected with the eliminator.