System Assessments

The information contained in this article, will help the operator to assess his/her systems, and identify where these systems fall within a three-level category. There are many ways, and opportunities to make a compressed air system produce reliable and good quality air. The three levels discussed here could also be characterized as a “continuous improvement plan” which can be achieved over the course of time, and with the occasional investment of money.

The purpose of this article is to point out the key performance indicators (KPI’s) that can assist in maintaining the performance and troubleshooting of compressed air dryers. The most important KPI to monitor is the pressure dew point (PDP) of the compressed air exiting the dryer(s). The PDP of the compressed air should be monitored at the discharge of each dryer and downstream of where the compressed air from multiple dryers converges. 

At the beginning of the 20th century, biological wastewater treatment — more specifically, the activated sludge process — was developed and became widely accepted as the treatment method for municipal wastewater, helping to protect our lakes and rivers from pollutants and support public health. In 1947, the Committee on Development of Uniform Standards for Sewage Works was created by the group known as the Great Lakes – Upper Mississippi River Board of State and Provincial Public Health and Environment Managers. 

Modified Atmosphere Packaging (MAP) accounts for a significant amount of nitrogen usage in the food and beverage industry. MAP involves injecting nitrogen into beverage or food packaging to purge and displace any oxygen-containing air with nitrogen. Oxidation of lipids in food products causes rancidity. Since oxygen is replaced with dry, inert nitrogen in MAP packaging, no product oxidation will occur. The result is maximized product shelf life. 

In this article we will discuss how to achieve actual oil-free air from your air compressor, no matter what type of air compressor it is. Air compressors of all designs turn mechanical power into pneumatic power by successively concentrating air across compression stages. A rotary screw air compressor, for example, utilizes rotating helical screws to drive air forward, increasing its pressure by reducing the volume of space the air mass takes up. Mechanical compression of this nature takes quite the force and energy to accomplish, which equates to heat generation and physical wear inside of the compressor. 

There are a tremendous variety of unique and creative ways people in the food industry have overcome their need for compressed air blowoffs used for cleaning, drying, cooling, conveying and overall processing. You may have seen some of them yourself. It is not uncommon to view open copper tubes, pipes with a crushed end, plugs or caps with holes drilled into them, modular flex coolant lines or nozzles designed for liquid application but blowing air.

Most industrial systems like compressed air have essentially random demand if you look at the long-term life cycle of the system. Hundreds, even thousands of independent small and large subsystems require constant or varying flow. These demands are typically not timed or synchronized with each other, so they aggregate to a fairly random flow profile, within a range. That range changes significantly when production processes change. Certainly a 2-week audit might show some patterns that appear predictable for demand A (“production”) and demand B (“non-production”) or day type, but they change over time as the plant adapts to new production systems and removes old ones. If demand was that profile forever, a lesser experienced auditor might be tempted to size one set of compressors that work perfectly for that profile but not for alternates.

The Wonderful Pistachios and Almonds campus in Lost Hills, California is a manufacturing facility that processes and packages pistachios and almonds for the consumer market. Food processing requires extensive use of compressed air to control multiple applications ranging from actuators, valves, optical sorters, packaging equipment and plant maintenance operations. The campus has its peak season during harvest in late August/early September, but processing and packaging operations take place year-round.

Pulse jet dust collectors are common air/material separators in the food industry serving as dust collectors, bin vents, and pneumatic conveying filter/receivers.  The biggest complaint I’ve heard from plant managers and plant engineers about these is that “these collectors don’t make us any money”.  While that is true, they can COST a plant a significant amount of money if they aren’t maintained.  Wasted compressed air is one of the worst offenders, as it not only costs the plant in energy costs associated with creating and conditioning the air, but also in premature bag failure from improper cleaning, production downtime, and inefficient dust collection leading to increased housekeeping requirements, and other many issues.

For Imerys S.A. there’s little question about the importance of managing dust collection systems it uses to control and reduce harmful particulates in its worldwide minerals processing facilities. And now there’s zero doubt about the tremendous energy savings it stands to save by reducing the amount of compressed air needed for these same dust collectors.