It is not uncommon in any type of processing operation to require gas or air to be free from entrained liquids. This can be done through several different methods, but a general option that works well for most applications are low flow or high flow knockout tanks.
The basic operation of knockout tanks, also known as knockout drums, is as a controlled and enclosed space that allows the gas containing the liquid or vapor to reduce the flow and pressure, allowing the entrained droplets to drop out of the gas and to be collected and removed. At the same time, any small particles contained in the gas flow, including organic and non-organic types of debris, also fall out of the gas.
Considerations for Systems
When selecting knockout tanks for any system or application, there are several features or options to consider. It is possible to add demisters to these tanks, which provides a greater level of vapor and liquid removal from the gas entering the tank.
The specifics for each application are different, and it is essential to match the tank to the requirements for the system. Sizing of the tank is another critical factor, as tanks that are too small are less efficient and do not provide the level of removal of the liquid. As a general guide, the diameter of the tank is the critical factor, with the higher the flow, the larger the diameter to manage the removal of the liquid.
For long duty cycles, look for knockout tanks that are fully epoxy coated to resist corrosion and damage. They should also meet all ASME requirements for pressure or vacuum based on the specific application. These tanks can operate on a gravity draining method, or they can be fitted with sumps and pumps for faster draining in high volume types of uses.