Industrial Utility Efficiency    

System Assessment

Annual plant electric costs for compressed air production, as operating today, are $147,469 per year. If the electric costs of $750 associated with operating ancillary equipment such as dryers are included, the total electric costs for operating the air system are $148,219 per year. These estimates are based upon a blended electric rate of $0.087 /kWh. The air system operates 8,760 hours per year. The load profile or air demand of this system is relatively stable during all shifts. Overall system flow ranges from 800- 1,000 acfm during production. The system pressure runs from 95 to 80 psig in the headers during production.  

Compressor Controls

UniFirst is one of North America’s largest workwear and textile service companies. They outfit nearly two million workers in clean uniforms and protective clothing each workday. Founded in an eight-stall garage in 1936, the Company has grown to 240 customer servicing locations throughout the U.S. and Canada servicing 300,000 business customer locations. The subject of this article is an energy-saving Air Demand Analysis (ADA), conducted by Kaeser Compressors, at UniFirst’s centralized 320,000 square foot hub Distribution Center located in Owensboro, Kentucky.

Piping Storage

The company specializes in fabrication of precision assembled customized parts for OEM’s and system integrators. Since 1997 the company has steadily grown in size and capacity as the demand for its high quality fabrications has increased.  Through the years, many new CNC machines, laser cutters and powder coat painting operations have been added, but with all the expansion the facility has amazingly kept the plant compressed air consumption low. This has been achieved by following excellent “best practice” compressed air efficiency principles and by keeping watch on system waste.

End Uses

A chemical plant spends an estimated $587,000 annually on electrical energy to operate their compressed air system. In addition, the plant has an expenditure on rental air compressors of equal or greater size - but this will not be covered in this article. The plant was built in the 1940s and modernized in the 1970s. The plant generates its own power and serves many processes. The average cost per kWh is $0.0359.

Pressure

A Canadian chemical plant installed a large heated blower-purge style compressed air dryer, years ago, to condition the instrument air system against freezing temperatures.  The dryer selected was oversized for the connected air compressors and had unused on-board energy savings features.  A compressed air assessment revealed the site air compressors and compressed air dryers were running inefficiently and causing in-plant pressure problems.  Repairs to a compressed air dryer and the replacement of aging air compressors and dryers has reduced compressed air energy costs by 31 percent.

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

Energy, in all forms, has always been a key Lantech focus. It was, in fact, a key element of the core packaging problem the company’s founders set out to address. They saw an opportunity to capitalize on an inexpensive and under-used resource – stretch film – to displace a high materials cost and energy intensive way of unitizing pallet loads of products – shrink bagging.

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.
Cement production facilities have a significant number of dust collectors. Many have continuing problems with short bag life and low-pressure problems at the further points from the central air system. They often run on timers. When they try to run on demand control, they often get extreme short cycling, which causes even more bag problems. Most have gauges at the entry, on at least half of the dust collectors, and the compressed air feed lines are always the same size as the connector opening. This article reviews where these problems come from and provides some troubleshooting ideas.
As plant personnel know, repairing compressed air leaks can be an expensive, labor intensive and never-ending process. This article discusses ways plant personnel can reduce and maintain their leak rate at a lower level without repairing leaks. It discusses how pressure/flow controllers, variable speed and variable displacement compressors, automation, and addressing critical plant pressures allow plant personnel to lower the header pressure, which eliminates artificial demand and controls the leak rate. More importantly, the article brings a new dimension to the idea of turning off the air to idle equipment by focusing plant personnel’s attention on the idle time within the cycle of operating equipment.
Compressed air is often overlooked in energy studies. For those willing to look, however, it is a land of opportunity. Since it takes about 8 hp of electrical energy to produce 1 hp worth of work with compressed air, it is also particularly rewarding to evaluate and optimize the compressed air system in your facility. In this article, we evaluate four specific areas of a compressed air system that can provide significant energy savings.
In this article, we review the operating principles of both basic types of pulse-jet dust collectors — bag (sock), and reverse flow filter. We then examine the effects of various installation and accessory selection issues through several case studies, providing examples of how to fix the issues and optimize the system’s compressed air use.
Vale in Thompson, Manitoba, Canada has reconfigured a system of large turbo compressors in their mining, milling, smelting and refining operation and gained very large energy savings through a series of improvement projects. In addition, these projects qualified for some significant financial incentives from their local power utility.  Vale is a large multinational mining company with headquarters in Brazil.  Vale operations focus on the production of iron ore, coal, fertilizers, copper and nickel.  The Thompson Manitoba operations consist of mining, smelting, milling, and refining of Nickel in the 250 acre complex that employs 1,500 people.
Compressed air audits for chemical and petrochemical plants have many characteristics in common with audits in other industries, but there are some differences in the way these businesses run that impact the goals of the typical audit and how that audit is conducted. In chemical and petrochemical facilities, the reason for auditing the demand side is different than that of other industries. Additionally, there are frequently applications with opportunities for improvement that are not always seen in other industries.  
A factory expanded their production facilities in response to a new product line being introduced in their plant. The plant was to run as a separate entity with its own utility services. Because this company is very conscientious about their energy consumption, they specified top-of-the-line compressed air production equipment to keep their costs low while maintaining the very clean air quality required by their product. This equipment should have worked wonderfully. Unfortunately, events transpired, and poor decisions were made that pushed their system out of control, resulting in unexpected inefficient compressor operation and higher-than-desired energy consumption.
This article introduces a new and useful compressed air system parameter called the “Compressor System Factor,” or CSF. The CSF of a given system defines the relationship between an air compressor, its system, and how the compressor is being operated. Knowing the CSF of a system allows comparisons to be made between existing operating characteristics and the characteristics of a proposed system. Changing a system by applying energy efficiency measures like adding storage receiver capacity, changing pressure bandwidth, or switching to different compressor control modes also changes the CSF. The results of the change can be easily predicted using the CSF number.
Corporate announces it is participating in the ISO 50001 Energy Management certification program and issues the edict to all itsmanufacturingfacilitiesto come up with plan to reduce energy consumption by 25%. Plant management calls a meeting to discuss how this ambitious goal can be met. Since energy is one of the largest controllable components in a compressed air system, the group decides to start there. Arecentsupply side assessment conducted in conjunction with a compressed air specialist confirmed the compressors are energy hogs. Based upon the analytical simulation run by the specialist, a recommendation was made to upgrade the compressor network with a System Master Control. The project is moving forward making it good starting point in the overall energy reduction plan. What next?
Acrylon Plastics located in Winkler, Manitoba, Canada manufactures an extensive variety of custom plastic parts for a wide range of end use applications. Years ago changes to their production volumes increased the compressed air flows to above what their compressed air system could deliver. As a result the plant pressure would fall to low levels during production peak demands, which negatively affected sensitive compressed air powered machines. In addition to this during light plant loading conditions the air compressors would run inefficiently. Plant personnel tried a variety of strategies to deal with the plant peaks, with the most efficient solution coming as a result of installing VSD style compressors and pressure/flow control.