What Is Compressed Air Dew Point – Why It Matters to Your Profits
Every compressed air operation benefits from processes that maximize product quality and minimize equipment maintenance. One way to accomplish this is to closely monitor the pressure dew point in compressed air to minimize unwanted condensation.
ISO 8573.1 addresses three critical impurities in compressed air: excess moisture, particulates, and oil. This compressed air standard sets forth testing parameters designed to maintain proper purity levels in compressed air.
Maximum dew point is one of three standards for determining compressed air quality. The other two are the maximum size of particulates and maximum oil content.
The dew point is the temperature at which air is fully saturated with water vapor at a constant pressure.
What Is the Dew Point of Compressed Air?
Since dew points are impacted by higher pressures, the term “pressure dew point” is used when discussing water vapor levels in compressed air. So, what is the dew point temperature of compressed air? Compressed air dew points range widely, from 50 degrees F to negative 94 degrees F.
High dew points yield multiple adverse outcomes. First, they result in damaging condensation in process equipment. Second, they cause excess water particles in compressed air lines and in the air itself.
Therefore, you must know your instrument air dew point specification, and you need to successfully monitor dew points to stay within recommended limits. Keeping pressure dew points under control is necessary for downtime-free process operation.
Measuring Compressed Air Dew Points
If you want to know how to check the dew point of compressed air, you must identify the right equipment for the task. Proper selection of monitoring equipment is related to the expected range of dew points, pressures and temperatures.
There are in-line sensors as well as those that utilize a sample line for external monitoring. There are also fixed-mount and portable devices. Use of the wrong sensor or device may fail to detect pressure dew point anomalies.
Dew points are measured by a variety of capacitive sensors, including aluminum oxide, thin film polymer and silicon oxide types. They may also be measured by chilled mirrors. Once you learn how to measure the dew point of compressed air, you can monitor operations with increased confidence.
Controlling Excess Moisture
It is possible to remove excess water vapor using refrigeration, membrane and absorption dryers.
The refrigeration process drops air temperatures to 35-40 degrees F. At these low temperatures, water condenses and drops out of the air. Upon completion of the process, the air is heated up again.
A membrane dryer simultaneously lowers the dew point removes contaminants from a compressed air system by employing a progression of filtration media.
Absorption dryers are used to dry air when dew points are in the range of minus 30-40 degrees C.
Pressure Dew Points and Your Bottom Line
Why is the compressed air dew point important to your profits? Because failure to properly monitor and control compressed air pressure dew points in process equipment often prove costly.
For example, excess moisture corrodes/rusts lines that are not zinc-coated. The resulting particles can block nozzles and harm control elements at sampling points, leading to downtime. Shutdowns are the bane of any operation.
Excess water vapor and/or condensation adversely impacts many industries. For example, in the pharmaceutical industry, excess condensation can potentially contaminate products through bacteria formation.
Successful management of instrument air dew points is vital in many different applications. Consider specific instrument air dew point requirements to optimize your processes and monitor the dew point temperature of compressed air to minimize avoidable expenses. You may need an industrial air dryer to maintain equipment and avoid corrosion.
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