Mist eliminators, or demisters, play an essential role in removing mists and other liquids generated during industrial and manufacturing processes. During these processes, droplets of water and other molecules may become trapped in the air or gas, resulting in entrapment.
As environmental protection regulations have increased, the use of scrubber mist eliminator has risen to meet these new requirements and reduce pollutants that gases may otherwise carry. Understanding how mist elimination works will help you choose a suitable mist eliminator for wet scrubber systems.
The Role of Mist Eliminators in Wet Scrubbers
The wet scrubbing process is designed to remove solid or liquid particles from a gas stream. This is done by merging the gas stream with a liquid like water to control the particulate matter. In environments where machines are used, it is essential to use moisture eliminators and control systems.
For a wet scrubber to work effectively, inertia and dispersion must apply. Wet scrubbers incorporate mist scrubber that help manipulate the gas to control these particulates and remove them from the air.
The mist eliminator’s role is to remove liquid contaminants from gas streams. Eliminating these contaminants helps improve plant emissions, promote product integrity, prevent equipment corrosion and reduce possible employee health risks. The design of a wet scrubber incorporates mist eliminators to remove liquid droplets. Contaminants and pollutants can become trapped if gas and liquid streams make contact.
In combination with mist eliminators, wet scrubbers can remove both particulate matter and gases. Additionally, a wet scrubber’s ability to collect droplets is directly proportionate to how much power the scrubber receives and how well the mist eliminator functions per its design.
Scrubbers are often considered to be excessively costly. However, they are quite straightforward devices and are frequently the most affordable and dependable option for removing particulates from a gas stream. The ongoing capital and operational expenses for any separation device rely on assessment. For wet air scrubbers, the cost evaluation frequently relies on the access to water and the systems for waste management or disposal. There are several common process reasons for using scrubbers for particulate separation:
- wet scrubbers are simple to build and operate
- wet air scrubbing is the most efficient way to cool high-temperature process gases for air treatment by quenching them with water
- wet scrubbers may be more compact than other industrial tools
- gaseous and particulate contaminants may be collected in the same device
- wet scrubbers may be the safest way of hounding potentially explosive, pyrophoric, or combustible dust
- wet air scrubbers can operate reliably on sticky or highly hygroscopic materials
Advantages of Mist Eliminator Considerations for Wet Scrubbers
Mist eliminators are a perfect addition to wet scrubbers and help enhance the cleaning of contaminated air. The three types of mist eliminators can be made to meet the specifications that you require for your wet scrubber system.
Mesh mist eliminators are relatively inexpensive and are efficient at removing small particles.
Filter bed mist eliminators filter smaller droplets extremely efficiently. Due to the large surface area of this type of mist eliminator, you can also filter a high volume of contaminated air.
Vane mist eliminators work across various applications, and the blade spacing can be adjusted for specific cases. You can arrange this type horizontally or vertically for high-capacity filtering. Out of the three mist eliminators, the vane-type creates the lowest pressure drop as gas is forced through.
What Affects Wet Scrubber Performance?
For a high-efficiency wet scrubber to perform as anticipated, it must have the correct setup and maintenance. However, having the proper structure is not the only aspect that affects performance. Issues can still appear after a time of efficient operation. Eight common factors can influence the efficiency and performance of a wet scrubber. Through troubleshooting these problems and conducting preventive maintenance, you can restore the scrubber’s operational capabilities.
The Importance of Preventive Maintenance for Wet Scrubber Efficiency
Quality design of a wet scrubber is essential to avoid some causes of efficiency drop. For instance, a well-designed scrubber will have properly designed air distribution and pump size. You cannot rely completely on the design of the wet scrubber to ensure performance. Maintaining the scrubber plays a major role in keeping it performing at its best.
Preventive maintenance can stop many of the most common problems of reduced performance. Maintenance chores include those conducted daily, weekly, quarterly and semiannually. Workers should check various aspects of the scrubber before starting it up. These checkups should not take much time, and they provide valuable information about the state of the components of the wet scrubber. Note that some types of wet scrubbers are more sensitive to changes in pressure or temperature, making monitoring and adjustments of these factors vital.
During wet scrubber operation each day, check the pressure drop, pH and signs of re-entrainment. Checking these aspects of the scrubber and making corrections to restore the unit to ideal operation reduces damage to components. For instance, unchecked pH can lead to crystal formation inside the scrubber, and re-entrainment leads to discoloration of the scrubber.
Once a week, examine the headers and nozzles for signs of plugs or erosion. Plugged or eroded spray nozzles can lead to channeling, which ranks among the common factors in the inferior performance of a wet scrubber. Empty the sump and clean it before refilling it with an appropriate liquid. Replacing the sump fluid weekly can prevent one of the top causes of reduced efficiency, which is inadequate fluid.
Quarterly, examine the entire wet scrubber for signs of leaks, and repair them immediately. At least twice a year, conduct an internal inspection of the components of the wet scrubber. Correct causes of solid accumulations in mist eliminators or tray orifices, clogged nozzles or eroded nozzles.
If you’re unsure which type of mist eliminator would be best for your facility, or if you need a custom wet scrubber system engineered for a specialized application, Torch-Air can help.