Compressed air is dried to prevent condensation and corrosion which can disrupt manufacturing processes and contaminate products. Water is the primary promotor of chemical reactions and physical erosion in compressed air systems. A myriad of desiccant dryer designs have been devised to provide “commercially dry” air, air having a dew point of -40°F or less, to prevent corrosion. Desiccant dryers use solid adsorbents in granule form to reduce the moisture content of compressed air.
What are the conditions inside your pipes, is it cloudy and hot with showers or cool and dry? Could there be snow and blowing snow and excessive icing conditions? Are there smog and dust storm conditions or is the air as fresh as a mountain breeze. All these conditions are commonly experienced inside compressed air systems. What you get is determined by your selection of system equipment, ambient conditions and how well your system is maintained.
Desiccant compressed air dryers offer a simple solution where very dry compressed air is required however there are some key issues which must be considered to make their operation reliable. In particular, excessive flow, low pressure, silencer back pressure and purge air must be carefully monitored and controlled. This paper discusses common issues affecting the reliability of compressed air desiccant dryers which lead to loss of performance.
Condensate drains are possibly the least glamorous and most ignored component of a compressed air system but nevertheless, a most important part. No matter how much you spend on that fancy new compressed air system, VFD’S pin-stripes and flashing lights notwithstanding, not spending a little effort with your drain choice could cause you no end of headaches and increased operating costs for years to come. Contaminants can enter a system at the compressor intake or be introduced into the airstream by the system itself. Lubricant, metal particles, rust, and pipe scale are all separated and filtered out, but it’s the drains that have to operate properly for the filters and separators to be successful in completing their task.
In the 1970s, the use of filtration in air quality management in pharmaceutical production, hospitals, and medical device manufacturing facilities became increasingly important and increasingly of interest to regulatory agencies. The air quality field was growing. From the air moving into and out of clean rooms to the protection of surgical environments to the expansion of the global medical drug industry, compressed air began to play a larger role—a role that continues undiminished (and, in fact, has increased substantially) today.
So you need nitrogen in your plant! In a high percentage of cases, generating your own nitrogen using commercially available equipment is a very cost effective alternative to purchasing liquid nitrogen or cylinder nitrogen from traditional supply sources like the industrial gas companies. In some cases, the return on investment (ROI) ranges from six months to 2 years, but ROI can range, depending on several factors, to several years while still being a good investment. With rising fuel and energy costs, the cost of liquid nitrogen is going up and is making it much easier to justify the purchase of a nitrogen generator in a wide range of purities and pressures.
One of the many tasks in assessing a compressed air system supply side is to analyze the air treatment system for appropriateness and efficiency. Most compressed air systems have one or more air dryers in place to remove the water vapor contained in the compressed air produced by the system air compressors. If there is no air dryer, the normally hot saturated air produced by the air compressors will cool in downstream system components, and condensed water will form in pressurized system pipework.
Nitrogen, an inert gas comprising 79% of the atmosphere, can be distilled from ordinary air. However, companies that use this product in their everyday operations know that it’s not quite that simple and much more expensive than the stuff we breathe. The primary means of obtaining nitrogen for industrial use is to transport it onsite in liquid form, which must be shipped stored at cryogenic temperatures. But, really, what’s the point of turning nitrogen into liquid for shipping, transporting it to where it’s used, and then turning it back into gas?
Production and quality engineers in industries like the food & beverage, pharmaceutical, semiconductor, and chemical sectors have established internal specifications for oil-free compressed air. The product spoilage and safety issues at risk make oil-free compressed air an absolute necessity in certain processes.
Nitrogen gas provides a number of diverse uses for a wide variety of manufacturers. As a sister function of compressed air, on-site nitrogen generation can provide additional opportunities for cost savings and other efficiencies for manufacturers who shift from delivered liquid nitrogen service.
Dewpoint is defined as the temperature to which a gas (e.g. air) must be cooled, at constant pressure, for water vapor to begin to condense to liquid water. In other words, when the dewpoint temperature has been reached, the gas is fully saturated with water vapor.