Questions You Should Know about fiber mist eliminator

Date: -07-07 | Author: Christine McAniff

For more information, please visit our website.

When exploring mist elimination solutions, it’s essential to find a reliable company that can tailor the right mist eliminator for your process. This guide will discuss the fundamentals of mist eliminators, often referred to as demister pads.

In industries like fertilizer and chemical manufacturing, liquid interacts with gas flow, leading to the entrainment of liquid droplets and the resulting mist. This mist can be corrosive, causing inefficiencies and damaging your equipment.

A well-designed mist eliminator effectively captures liquid droplets from the gas stream. The process occurs when droplets strike the mist eliminator, coalescing on the demister pad’s surface and forming larger droplets. These larger droplets eventually flow downwards into the drainage area below for recovery or removal.

One significant issue that arises in mist elimination is plugging. This occurs when substances accumulate on the mist eliminator's surface, leading to blockages and pressure drops. It’s common for process and gas stream complications to stem from the plugging of the demister pad. Such plugging can cause product loss, increased energy usage, corrosion, shortened equipment lifespan, and impact plant output. Notably, structured media mist eliminators are less susceptible to plugging compared to traditional knitted mesh.

When selecting a mist eliminator, it's crucial to partner with a company that understands your chemical processes and can design a mist eliminator that meets your specific requirements. Whether for retrofitting or new installations, several factors must be considered in the demister pad's design. For instance, determining particle size is key in deciding between different mist elimination methods, such as Fiber Bed Filters or Structured Mesh Pads. Recognizing the size of droplets in your current system is necessary, focusing on their diameter—sprays being larger than 10 microns, mist ranging from 10 microns to 1 micron, and aerosols being less than 1 micron.

Droplets are captured on the mist eliminator media through three primary methods: inertial impaction, interception, and Brownian diffusion.

For larger droplets, inertial impaction occurs when droplets between 20-30 microns travel straight, moving away from the gas flow and striking the media's surface to unite.

Interception occurs with droplets as small as 1 to 3 microns, which are unable to navigate through the media's fibers and consequently get caught.

Brownian diffusion pertains to particles smaller than 1 micron, colliding with gas molecules, gaining momentum and random motion that increases their chances of contacting the fibers.

Link to ZHUAN LV

Mist Eliminators Come in Various Styles:

Vane packs, also known as chevron or plate-type mist eliminators, consist of corrugated plates closely spaced, creating a convoluted path for the gas flow. These devices are effective for larger droplets but can be quite expensive.

Fiber bed filters utilize fine fibers, often made from glass or plastic, wound around a cylinder. They can be re-packed and replaced but should not be employed in environments with solids.

Wire mesh, also referred to as knitted mesh, consists of multiple layers made from metal or plastic. These pads can be cleaned and reused.

Structured mesh mist eliminators feature interlocking plastic monofilaments, which can also be cleaned and reused. When designed correctly, larger diameter polypropylene mesh pads can manage particulates better, minimizing pressure drop risks.

Poorly designed mist eliminators may cause upstream equipment corrosion, product wastage, and extended downtimes.

When designed accurately, mist eliminators can reduce plugging and mist carryover, lower pressure, cut energy consumption, lessen maintenance needs, protect downstream equipment from damage, reduce corrosion, prolong equipment life, and decrease atmospheric emissions—all leading to greater profitability.

Fiber bed mist eliminators consist of deep layers of very fine fibers situated between two concentric cylindrical screens or cages. The material used—chemically resistant glass fibers, synthetic fibers, and other specialized fibers—depends on the environment of the process. Structural screens, cage parts, and flanges may consist of any weldable metals, plastics, or glass-reinforced resins.

All fiber bed mist eliminators function similarly. Gases containing mist particles are directed horizontally through the fiber bed, where the mist particles collect on individual fibers, coalescing into liquid films. The gas flow moves these liquid films through the fiber bed, and gravity aids in draining the liquid from the downstream face of the bed. Typically, fiber bed mist eliminators are installed within vessels or tanks, with the collected liquid continuously draining.

An innovative fiber bed design involves adding a coarser fiber layer on the downstream side, which enhances drainage and prevents the re-entrainment of liquid back into the gas flow.

For more information, please fiber mist eliminator.