System Assessments

Over the last two decades, there has been a significant increase of manufacturing facilities deciding to produce their own nitrogen on-site, using compressed air systems and nitrogen generators. They are choosing on-site nitrogen generation, instead of purchasing and receiving deliveries of nitrogen by the cylinder or having a “Nitrogen Over the Fence” supplier.  

A ‘Process’ application, is one where it’s all about controlling the contents of a vessel, pipeline, or chamber.  What is the gas makeup inside the vessel? How much of it is in there? All means to control a chemical and/or thermodynamic reaction so that we add value to some base ingredients to convert them into a marketable product. 

In this article, we will provide detail on the characteristics of the baseline system and then share the energy-saving work identified in two projects. These two projects represent work which can be performed by the maintenance teams in every plant. These are also project opportunities we find in almost every plant we visit. The two projects are to (1) repair/replace condensate drains wasting compressed air and (2) to perform a compressed air leak survey.

This assessment identifies a path to reduce the energy consumption from \$85,000 to \$51,000 per year. This can be done with little capital by fixing poppet-valve control problems on the air compressors and reducing flow and pressure requirements. Due to article space limitations, this article does not provide detail on the flow reduction projects. It focuses only on the impact these projects have on the air compressors and provides readers with a template on the information they should have on their units, by shift.

There were two situations brought to our attention. The first was that production at times was having to slow down, or even stop, due to compressed air system pressure falling below the required levels. The second reason was due to reports, from plant personnel, of compressed air moisture problems negatively affecting the bag life of the dryer baghouses.

Their system was designed and built to achieve premium performance, yet in a recent compressed air assessment the numbers showed their system had surprisingly poor performance, and worse, their staff was unaware of the problems. This article discusses some of the challenges faced and some future solutions that could get their system back to higher performance levels.

Vane motors can run at much higher speeds (2000 rpm and up), but piston motors tend to turn much slower – less than 1000 rpm. For slower speed applications, vane motors are mated with a gear reducer and called a gearmotor. The gearmotor can produce the higher torque and slower speed needed for some applications, but the gear reducer can add some drivetrain loss. While a piston air motor may not be able to replace a vane motor where high speed is needed, it can be a good choice for high torque/low speed applications.  

Utilities monitoring paired with machine learning models can reliably predict anomalies, prompting action that can prevent waste and optimize resource use. 

If there was ever a place where manufacturers can save energy using compressed air and make measurable gains toward sustainability, it’s with pneumatics that power a seemingly infinite variety of machines and processes.

The initial cost of a nitrogen generation system may be greater than high-pressure cylinders and liquid nitrogen containers, but most companies will reach a return on investment within 12-18 months with proper sizing of the system based on process demands. Breweries typically experience savings associated with gases of 50-75% by switching to on-premises nitrogen generation. If a regular maintenance schedule is followed, PSA nitrogen generation systems can have a life expectancy of 15-20 years.