When gas is contaminated with water-soluble organic compounds — such as ethanol, propanol, acetone and formaldehyde — it’s often scrubbed with a water-only scrubber. Water-only scrubbers use water as a solvent to strip gas of organic contaminants. Water-only scrubbers are sometimes referred to as water once-through scrubbers, because the water isn’t reused, unlike the water or solvent in other scrubbing solutions.
Common Uses of Water-Only Scrubber Systems
Water scrubbers have several industrial applications, including power generation and the manufacturing of steel and asphalt. Sometimes, water scrubbers contain pollutants that would be expelled from the industrial exhaust streams. In any situation where gas can be contaminated by organic compounds, a water-only scrubber system can strip the gas of those contaminants. Water scrubbers can also collect dust and other particulate matter at the same time they separate organic contaminants from gas.
Water scrubbers are often used in situations to minimize fire risk, or where the contaminated gas needs to be at a high temperature or highly pressurized. Water-only scrubbers are also very space-efficient, and you can use them when other scrubbing solutions would require too much area or volume.
How Water-Only Packed Scrubbers Work
The contaminated gas flows into the scrubber and over a bed of packing — small, often hollow objects designed to maximize the contact area between gas and solvent. Tri-Packs and MACH Mini Rings are often suitable packings for this type of scrubbing. At the same time, water enters the scrubber, flows in one direction and then exits, now carrying the target contaminant. Because the contaminant is water-soluble and the target gas is not, this scrubbing method will effectively separate out the organic contaminants from the gas phase.
If the gas didn’t become fully “clean,” or if more scrubbing is necessary, new water will flow in. The contaminant-containing water won’t pass through the scrubber again, as is the case with some other types of solvent- and water-based scrubbers.
These types of scrubbers have some special design limitations in mind. The scrubbed contaminants can be highly volatile — or, at least, more volatile than water. The water exiting the scrubber needs to be properly contained to avoid exposing the contaminants to the environment. This is especially true if you use the scrubber to prevent pollutants from getting released into the atmosphere.
Customized Scrubbing Solutions
When you are looking for a customized scrubbing solution, you can count on MACH Engineering. We have an entire team dedicated to helping clients design and implement a water-only scrubber system that works for your industry and need. Contact us today to start the design process.