Industrial Utility Efficiency    

System Assessment

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.

Compressor Controls

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. 

Piping Storage

Replacing unreliable air compressors is often a smart choice. Sometimes there is a better one. Take the case of a wallboard plant with two compressed air systems, including one for its board mill and another for its rock mill. Each had two 100 horsepower air compressors, all of which constantly overheated. When they did, plant personnel had to scramble to turn on a machine manually every time a unit shut down. Three units ran the plant so any shutdown had them walking on pins and needles.

End Uses

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.  

Pressure

Whenever we start a compressed-air energy survey there are always two key topics plant personnel feel are paramount – leaks and reducing pressure. In this installment of our series on missed demand-side opportunities we’ll address the importance of compressed air system pressure.

Air Treatment/N2

This plant has three production lines producing snack food. Depending on the time of year and production demand the plant can operate anywhere from no production lines to all three production lines. A thorough supply and demand-side system assessment was done at this plant. This article will focus on some recommended demand-side reduction projects including nitrogen generation, air vibrators, leaks and vacuum venturis.

Leaks

Petro Chemical Energy, Inc. (PCE) specializes in energy loss surveys for the refining and chemical industries. We’ve been providing Compressed Air Leak Surveys, Nitrogen Leak Surveys, Steam Leak Surveys and Steam Trap Surveys – for over twentyfive (25) years. We operate totally independent of all equipment manufacturers to ensure our clients receive a complete and unbiased report of the leaks in their facility. PCE has conducted compressed air leak surveys for hundreds of customers at thousands of sites. Undetected, compressed air and gas leaks rob efficiency in manufacturing and processing industries. As a result, businesses lose millions of dollars annually in energy costs and lost production time.

Pneumatics

Machines for filling milk or juice must often work around the clock. Given the critical importance of uptime, Elopak opted for Aventics food-compliant pneumatics when developing its E-PS120A - the first fully aseptic filling machine for gable top packaging. With an output of up to 12,000 cartons per hour, disruptions and downtime are not welcome with the aseptic filling machine.

Vacuum Blowers

Every municipality and utility is facing the reality of rising energy costs. In 2010, the Town of Billerica, MA, which is located 22 miles northwest of Boston with a population of just under 40,000 residents, engaged Process Energy Services and Woodard & Curran to conduct an energy evaluation of the Town’s Wastewater Treatment Facility (WWTF) and pump station systems sponsored by National Grid. The objective of the evaluation was to provide an overview of each facility system to determine how electrical energy and natural gas were being used at the facility and to identify and develop potential costsaving projects.
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. 
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.
By finding a better way to control and manage its compressed air system, North American Lighting, Paris, Ill., has reduced its total compressed air energy use by 27 percent – and in the process – saves over 1,100,000 kWh/year for a total annual savings of $91,000. The project also achieved a payback of less than one year.
A food processor in Western Canada hired an auditor to assess the energy efficiency of its compressed air system. The results revealed surprises about the operation of some important elements of the system, and detected that the air compressors were having control gap problems. Additionally, the audit led to initial energy savings of $20,000 – and identified the potential to achieve overall operational savings of 45%. The following details some of the audit findings and results.