11/22/2021 | Industrial Wastewater | 8 MINUTE READ
Wet Scrubbers and Industrial Applications
When you work in an industrial setting, it’s likely that your facility contains numerous exhaust streams that occur as the result of many different processes. Before these streams can be safely released into the environment, environmental regulations state that a certain amount of contaminants and pollutants must be removed from the exhaust streams. An industrial wet scrubber is a system that can effectively remove harmful odors and contaminants from any exhaust stream in your facility.
There are two types of industrial scrubbers that your facility can use, which include wet scrubbers and dry scrubbers. Wet scrubbers push contaminated gas streams through a water solution to remove any inorganic contaminants. This type of scrubber is commonly used across all types of industries because of its efficacy and efficiency. The main industries that use wet scrubbers include chemical, semiconductor, and metal finishing industries. Any facility that produces corrosive gases or fumes can benefit from a wet scrubber.
While dry scrubbers are able to produce sufficient results, wet scrubbers are more effective at getting rid of high levels of contaminants and are particularly useful when installed in wastewater treatment facilities. While there are plenty of treatments that can remove pollutants from wastewater, wet scrubbers are ideal for getting rid of odorous fumes that can be found in wastewater. The main benefits of using a wet scrubber include:
- The processing of incendiary gases can be handled safely
- High-temperature and high-humidity gas streams can be handled without condensation issues or temperature limits
- Collected particulate matter cannot escape once collected
- It’s possible to effectively neutralize some of the more corrosive gases
- Solid and gas particulate matter can be absorbed with one system
- You don’t need ample amounts of space for the installation of a wet scrubber
One type of industrial scrubber that you can have in your facility is an acid fume scrubber. Wet scrubbers are considered to be a type of acid fume scrubber. However, most wet scrubbers are able to eliminate far more contaminants than just acid. This article offers a comprehensive guide on wet scrubbers and the numerous industrial applications they have.
Wet Scrubbers vs. Dry Scrubbers
If you want to install an industrial scrubber in your facility, there are two types of scrubbers at your disposal, which include wet scrubbers and dry scrubbers. Understanding the main differences between these two systems should help you determine which one is right for your facility. In most cases, dry scrubbers are unable to remove as many pollutants as wet scrubbers. On the other hand, a dry scrubber may be beneficial when installed in a facility that doesn’t have the necessary infrastructure to support a wet scrubber.
Dry scrubbers are able to remove contaminants from exhaust streams without needing to use a liquid solution. These systems use a sorbent, which is a dry reaction material that can capture contaminants from exhaust gas. One example of a sorbent is alkaline slurry. These materials are mainly designed to remove acid from gas, which occurs by pushing the gas directly through the sorbent in order to substantially increase binding.
Wet scrubbers work by taking contaminated gas through a water-based solution to get rid of any pollutants that remain in the water. Even though these scrubbers have higher upfront costs when compared to dry scrubbers, they are a more cost-effective solution in the long run. When functioning properly, wet scrubbers can remove over 99% of airborne particulates, which means that you can be confident in the quality of your facility’s gas streams before they enter the environment.
How do Wet Scrubbers Work?
While several different types of liquids can be used in wet scrubbers, water is the most commonly used liquid when removing inorganic contaminants from exhaust streams. Keep in mind that there are numerous types of wet scrubbers, which means that each type functions somewhat differently. The most basic type of wet scrubber involves water that’s placed in a composite or metal container. The contaminated gas will then be sent through the water, after which the water will directly absorb the contaminants. Once the gas exits the scrubber, it should be largely free of contaminants.
As mentioned previously, it’s possible for wet scrubbers to remove over 99% of airborne contaminants, which makes this a highly effective solution for numerous industrial applications. Wet scrubbers are able to get rid of odors as well, which may be necessary for your specific application. While water is the most commonly used solution for wet scrubbers, there are a range of additional liquids that you might want to pair with your wet scrubber.
The exact solution you use depends on the types of contaminants you’re attempting to eliminate from your exhaust streams. By changing the chemical composition of absorbing solutions, the charge within the solution will change. As such, the solution you place in the wet scrubber can be negatively charged, positively charged, or non-charged. Different contaminants have different charges, which means that some solutions will be better than others at removing certain contaminants.
If you’re attempting to move acid out of a gas stream, the most effective scrubbing liquid is a caustic solution, which can be something like sodium hydroxide. Calcium hydroxide and sodium carbonate are two additional solutions that you might want to use with your wet scrubber.
When you’re using wet scrubbers to remove particulate matter, the matter can be captured in liquid droplets. The contaminated gases will usually be absorbed or dissolved in the liquid. If the scrubber inlet gas contains any droplets, these droplets will need to be separated from the outlet stream with a mist eliminator. The scrubbing liquid should also be treated before it’s discharged or used in the facility.
The ability that a wet scrubber has to collect particulates depends on how much power is being sent to the system. If you want your system to be as efficient as possible, it’s important that you pair it with a mist eliminator. In the event that an exhaust stream contains gases and particulate matter, wet scrubbers are typically the only systems that can properly remove both types of pollutants.
Types of Wet Scrubbers
There are five distinct types of wet scrubbers that could be installed within your industrial facility. The exact type of wet scrubber you use depends on the specific needs that your facility has. The five types of wet scrubbers available to you include:
- Chemical/gas scrubbers
- Particulate/venturi scrubbers
- Ammonia scrubbers
- Chlorine scrubbers
- Sulfuric acid scrubbers
Chemical/gas scrubbers are designed to get rid of at least one gas pollutant from an exhaust stream. These pollutants are usually chemicals, which include everything from sulfur compounds and chlorine to ammonia. Once collected, the chemical will be absorbed or dissolved. A chemical/gas scrubber can be operated on a long-term, continuous basis without needing to maintain the system too regularly. The need to remove chemical pollutants from gas is common across many applications, which include metal finishing processes and chemical processes.
Particulate/venturi scrubbers have proven to be effective at getting rid of particulates from an exhaust stream with high efficiency. These scrubbers can handle gas streams that are heavy in particulates, contain ample amounts of moisture, and have a high temperature. These systems can also collect upwards of 99% of particulates. They are unique because they are comprised of a venturi tube. Venturi scrubbers are commonly used in food manufacturing and corn processing facilities.
Ammonia scrubbers are designed specifically to get rid of ammonia, which is a type of colorless gas comprised of nitrogen and hydrogen. If high amounts of ammonia are inhaled, the eyes and nose can become irritated. The law requires ammonia scrubber systems to be installed in all chemical processing facilities. Ammonia can be removed from a gas stream and eventually neutralized with a chemical reaction.
Chlorine scrubbers are primarily used in facilities where chlorine is a typical byproduct. Many chemical reactions produce chlorine, which is when a chlorine scrubber may be needed. Keep in mind that chlorine gas is considered to be highly toxic. A standard chlorine scrubber takes a multi-stage approach to chlorine removal. An alkaline liquid solution is the most effective liquid for a chlorine scrubber. The efficiency of your chlorine scrubber depends on the chlorine concentration, process conditions, and scrubber design.
A sulfuric acid scrubber has a design that’s similar to ammonia and chlorine scrubbers. Sulfur-based substances are toxic and should be removed in the event that the processes in your facility produce them. When you use a sulfuric acid scrubber, the sulfuric substances will be captured in droplets of water before being disposed of. All sulfuric acid scrubbers contain mist eliminators.
Wet scrubbers are highly recommended for all facilities that produce contaminated gas streams. While dry scrubbers are available, they aren’t as effective as wet scrubbers and may not provide you with the results you’re looking for. Keep in mind that getting rid of pollutants with the aid of wet scrubbers may allow your facility to more effectively meet environmental regulations.