Industrial Utility Efficiency    

Technology

It is becoming a “best practice” to install a variable frequency drive (VFD) air compressor whenever one is replacing an old air compressor.  As a result, real systems have fixed-speed and VFD air compressors, mixed.  I have observed several VFD compressor sizing methods.  In my last article, I referred to a common method: size one VFD compressor for the whole system.  This can work.  However, if it doesn’t meet a higher peak demand, one or more of the old compressors will be started, and a mixed system results.   Another method is to replace a compressor with the same size, but with a VFD.  If the compressor that was replaced is large, a big VFD is installed.  If small, a small one.

Air Compressors

There are many choices of compressor technology and types of controls that can be used for variable demands. Some examples are rotary screw compressors with inlet valve control: variable speed drives: load/unload control; or centrifugal compressors with variable inlet guide vanes. However, in many cases, the efficiency of the overall compression process can be reduced significantly during lower flow demands, leading to more power per unit of air flow being delivered. It is very important to evaluate different available options and see how a plant can run most efficiently.

Air Treatment

Compressed air is dried to prevent condensation and corrosion which can disrupt manufacturing processes and contaminate products. Water is the primary promotor of chemical reactions and physical erosion in compressed air systems. A myriad of desiccant dryer designs have been devised to provide “commercially dry” air, air having a dew point of -40°F or less, to prevent corrosion.  Desiccant dryers use solid adsorbents in granule form to reduce the moisture content of compressed air.

Blowers

High speed bearing technology is applicable for aeration blowers operating at much higher speeds than the typical 60Hz, 3600RPM for cast multistage units. High Speed Turbo (HST) units are usually single stage (though some utilize multiple cores) and rotate from 15,000 to 50,000RPM. At such high speeds, standard roller bearings cannot offer the industry standard L10 bearing life. Two types of bearing technologies have come to dominate the wastewater treatment market for these types of machines: airfoil and magnetically levitated. Often the two technologies are compared as equals, however, in many significant ways they are not.

Compressor Controls

Load-sharing is an important part of a multiple centrifugal-compressor master control system. It minimizes blow-off based on the available turn-down. In addition, remote start-stop saves more energy if load floats between different ranges. Finally, adding a screw compressor and implementing a hybrid control system might save the most energy and provide the best back-up. In any case, a well-instrumented system allows engineers and operators to assess, optimize and tune the system.

Instrumentation

Compressed Air Best Practices® Magazine interviewed Mr. Warwick Rampley, the National Sales Manager for Sydney (Australia) based, Basil V.R. Greatrex Pty Ltd. It’s not every day one is asked to deliver a system able to provide both a reliable compressed air dew point of -80°C (-112°F) and high purity nitrogen.  We work with some excellent technology suppliers and have engineered a rather interesting system.  Although our firm was founded in 1919, this application is one of the most demanding we’ve encountered. Basil V.R. Greatrex is a unique company as we focus only on compressed air measurement, compressed air quality and compressed air efficiency.

Pneumatics

The design of wastewater treatment plants is changing, and it has something to do with LEGO® bricks. More specifically, it has to do with how large and complex LEGO structures are built. If you follow the instructions carefully, you build module after module, eventually piecing them together to create a fully functional and cohesive unit.

Vacuum

It’s one thing to move materials during the production process, but when it’s a finished product on the packaging line, choosing the right material handling system is essential. Getting it wrong results in squandered production time when product loss occurs, and wasted raw materials.

Cooling Systems

As a result of compressed air awareness training and a focus on energy management, two facilities in different parts of the world have reduced their compressed air demand substantially by removing vortex style cabinet coolers from some of their electrical panels and reworking the cooling systems.  These facilities were previously unaware of the high cost of compressed air and how much could be saved if other methods of cooling were used. This article describes some of their efforts in demand reduction.
In February of 2008, a sugar plant near Savannah, Georgia suffered the ultimate tragedy. Fouteen employees were killed and 40 injured when finely ground motes of sugar dust ignited, setting off a violent blast. If the fatalities and a tarnished reputation weren’t enough, the Occupational Safety and Health Administration (OSHA) then fined the company more than 8 million dollars in workplace violations related to combustible dust.
Nuclear power plants produce electricity for people, business and industry.  Electricity is produced in a similar fashion as fossil fuel (i.e., coal, oil, etc.) power plants, using steam to drive a turbines which spin an electrical generator, producing the electricity. 
Industry standards serve a very important purpose for the end users of compressed air equipment.  If the standards are well written, they can help to promote the equipment that they govern, as long as the equipment manufacturers properly apply and promote the standards.
Utilities have been cleaning their boilers for many years using either steam or high-pressure air.  In the past, when air was used, due to the size of the boilers and the reasonable quality of fuel used, a relatively small amount of cleaning was required.
Pneumatic system overhaul for furniture machining center yields high-precision results for a perfect, polished finish.
Safety is the driving force in the determination of minimum recommended supply wire sizes for variable speed compressor packages.  With this in mind, all wire size recommendations should be based on meeting, or exceeding, the minimum requirements of the National Electrical Code (NEC).
Boeing Canada has replaced their onsite membrane style Nitrogen generator with a new more modern system with increased capacity and higher efficiency.  As a result, the company is now using minimal amounts of expensive liquid Nitrogen, and has reduced the energy cost per unit of gas produced by 83%.
Relatively few people realize that for a variety of industrial manufacturing applications, from air knife drying to simple blow-off nozzles, the use of high pressure compressed air that bleeds into the atmosphere represents a significant waste of energy.  
With all of the different LEED credits and associated M&V requirements and tax incentive opportunities for businesses to reduce energy consumption, we have seen an increasing demand for metering. Companies are looking for more ways to estimate cost savings and prove that their energy saving investments are working.
This steel processing facility has been operating for over one hundred years.  This facility is part of a large corporation with numerous plants around the world.  This audit focused on the compressed air system on one side of the Works which we will call the “North Plant”.