Industrial Utility Efficiency    

System Assessment

This article discusses some experiences in using cellular connected data loggers to perform a compressed air assessment during a time when travel was restricted. While not ideal, this exercise identified huge savings for this customer.

Compressor Controls

As part of its ongoing corporate initiative to find ways to reduce its energy bills, and the costly impact on the bottom line, a cleaning products plant, located southwest of Chicago, recently focused on improving their compressed air system operation. This company is a global leader in water, hygiene and infection prevention solutions and services. This article discussed their efforts to improve the operation of their compressed air system by implementing an innovative compressed air monitoring and control system.

Piping Storage

Since completion of the system upgrade in the fall of 2020, PC Forge is on track to save an average of 1.9 million kWh and $266,000.00 per year in energy costs – and increase the production capability of its forging operation by 40%. The project also achieved a one-year payback with a $245,000 incentive from Government of Ontario’s utility Independent Electricity System Operator (IESO).

End Uses

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.

Pressure

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.

Air Treatment/N2

Regular testing of pure gases helps to ensure the safety of consumers and of end products. Whether the pure gas is used directly for medical patients, or in the manufacturing of food, beverages, or pharmaceutical products, quality is of the highest importance. Inadequate levels of purity or unsafe contamination can be detrimental to the products or consumers.

Leaks

One of the best ways to reduce compressed air costs is to look for ways to reduce leakage flow, an unnecessary load that is a constant demand on the compressed air system. This flow is never-ending and occurs during production periods, and during quiet times at night or on weekends. Reducing the flow in a well-controlled compressed air system will result in the reduction of compressor energy consumption, usually by about $1,750 per every 10 cfm, and often reduces pressure loss, allowing your machines to run better. This article discusses some recent experiences in using an acoustical imaging leak detector.

Pneumatics

In manufacturing and packaging facilities that rely on pneumatics, there’s a four-letter word worse than virtually any other: leak. Unidentified air leakage and unexpected maintenance in pneumatic systems are significant sources of revenue and productivity loss but identifying the cause of leakages and preventing unforeseen downtime is typically a challenge.

Vacuum Blowers

Operating the vacuum system at higher levels (then necessary) affects the needed volumetric flow to compensate for leaks. This required compensation of volume (ACFM) must be added to the nominal production flow demand. The ambient air leak into the system will expand to the highest vacuum level, which is known as the “Expansion Ratio.”
In terms of compressed air systems, it’s not unusual to see a plant with 10 to 15 air compressors, each of which is rated to provide 3,000 to 4,000 scfm of air. The air is used for everything from moving product, to powering pneumatic tools, pumps, and fans, to cleaning. There are easily 1,500 pneumatic control valves at a single plant.
Plant personnel had experienced ongoing problems with its process grinder performance due to unstable compressed air pressure. This created potential problems in terms of product quality. Grinders do not work properly without the proper pressure. Additionally, plant staff wanted to address these concerns, prior to a proposed 30% increase in production, and suggested raising the header pressure from the current operating pressure of 98 psig to 125 psig. The thought behind this was if the pressure from the header to the grinder process was dropping to 63 psig, then raising the pressure to the process would give the grinders enough pressure to work through higher peak production times.  
All industrial facilities use some form of compressed air, and in most, the air compressors consume a significant amount of the total energy bill. A facility with a good energy management system is likely to identify their compressed air system as a significant energy user (SEU). If the facility were using an energy management standard, such as ISO 50001, they would be required to assess and track the energy consumption of all their SEU’s. In the case of the metal processing facility, they were measuring the output of more than 250 devices within the plant, including building heaters, RTU’s, dust collectors, and also tracking the consumption of their electricity, natural gas and water. 
One observation I’ve made from 30 years of working with compressed air systems is to never underestimate the ingenuity of plant personnel when it comes to misapplying compressed air. We see something new in virtually every plant we visit, but one of the more common problems we encounter involves the use of expensive air for bearing cooling. 
By addressing inappropriate uses of compressed air and making changes to the compressed air production side of their compressed air system, a distiller of fine alcohol products reduced its energy consumption by 30%, saving $16,600 per year in energy costs - with more potential savings possible.
Experienced auditors become wary when they see desiccant dryers installed in customers’ plants. These dryers are required when a plant needs instrument-quality compressed air, or when compressed air piping is exposed to freezing temperatures. However, while desiccant dryers can gain this level of quality, the energy cost of stepping up from a dewpoint of 35 oF to a level of -40 oF increases quite considerably. To attempt to reduce the energy costs of drying to these low levels, heated blower desiccant styles may be used. This article describes three common desiccant dryer types, as well as some experiences, good and bad, with heated blower types.
This major food manufacturing plant in the Midwest uses compressed air and onsite nitrogen generation to operate multiple snack production and packaging lines. The plant spends an estimated $430,344 annually on energy to operate its compressed air system based on an average rate of 4.5 cents per kWh.
In most industrial plants, data is everywhere. It resides in flow through pipes, pressure in tanks, vibration on rotating equipment, temperatures in heat exchangers, and electrical energy power consumption in motors. If we can acquire this data and make sense out of the patterns we can take actions to make our plants more efficient and reliable.
On a recent project, at a polyethylene terephthalate (PET) blow-mold and filling operation, a very effective measurement plan resulted in a full synchronization of the supply side air to blow molds with significant reduction in total air use and increases in productivity and quality.  
To address a mandate for cutting operations energy usage at facilities by 25 percent without major capital expenditures, a major manufacturing company set its sites on better control of its compressed air systems.  The project, implemented at 10 manufacturing plants over the course of three years, saves the company $977,093 annually in energy costs – and was completed with zero out-of-pocket costs.