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 dryers need to get the ball handed to them on the 25 yard-line by a compressor providing low enough temperature, and high enough pressure for the dryer to take it to the design dew point. If not, the dryer is not able to work properly. Once the dryer gets the right moisture level, it needs to operate properly. Heat exchangers, drains, switching valves, etc., all have to work with the proper control sequence to provide reliable dew point to the plant.

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.
ANSI /ISA–7.0.0–1996 is the globally-recognized quality standard for instrument air as defined by the Instrument Society of America. In this article, we’ll go through the Standard’s four elements of instrument air quality for use in pneumatic instruments.
The air we breathe and the air compressors ingest is a mixture of gases, aerosols, biological material, and particulates. It’s a real mess! Particulate, for instance, is very harmful to humans, because lungs are complex oxygen separators, not filters. They tend to load up with particulate, this is harmful over time. There isn’t a sufficient “pre-filter” to prevent all harmful particulate from entering the lungs. However, humans prefer water in the air, gas, aerosol, and to a certain level, liquid form. A de-humidifier would not typically be a healthy addition to our built environments.
Larger air compressors, typically over 500 hp, in refineries, pulp and paper plants, chemical and other processing plants often have high-speed, multi-stage air compressors called “centrifugal” air compressors. As seen from a total system perspective, they are not much different than screw air compressors. They compress air to plant pressure from atmospheric conditions, and deliver it to the dryer. These types of air compressors have no internal wearing parts, besides bearings and seals, and are very reliable and efficient, at their best efficiency point. 
Knowing when to overhaul a unit is important, and there are certain signs indicating a unit needs attention. Performing routine fluid checks, taking oil samples and routinely checking for bearing vibration can unveil indicators suggesting an upcoming failure. Oil contamination with metal fragments usually indicates parts are wearing. It’s also important to take notice of airend temperature increases. If internal air compressor temperatures go up, it’s a good indicator the cooler may be failing.
When a system has the right combination of VFD and base-load air compressors, how do you coordinate their control? What tells the air compressors to run and load, to have just enough (or no) base-load air compressors and a VFD running, all the time air is needed? Appropriate master controls are needed. These controls are often called “sequencers” or “master control systems”.
The 2017 AICD Conference and Exhibition was held May 21-23 at the Grand Sierra Resort in Reno, Nevada.  The membership of the Association of Independent Distributors came together to share ideas and discuss business methods to help their businesses prosper.  “The AICD has grown by 15% with 9 new distributor members,” said AICD President Phil Kruger. “The event provides both members and vendors with excellent educational and networking opportunities designed to help grow our businesses.”
As an end user, have you ever heard the message to put in the biggest VFD air compressor, and the system will always be reliable and efficient.  Why do an audit?  Just add up the compressors on site and put one VFD for that size or larger.  Why have the complexity of multiple compressors, storage, sequencing, etc?  Even better, put in two of them, one for the whole system, and one for back-up.  If you could wave a wand, wouldn’t that be what every system should look like?  Perfect peace and efficiency, with 100% confidence of reliability.
The 2017 Hannover Messe attracted 225,000 visitors with 75,000 coming from outside Germany. The over-arching theme of the event was the Industrial Internet of Things – or Industry 4.0, as it is known in Germany. Dr. Jochen Köckler, Member of the Managing Board at Deutsche Messe commented,“Over the past five days, Hannover has served as a global hub for all things related to Industrie 4.0. Every sector involved in the digitalization of industry was on hand to showcase its answers to the key question faced by industrial enterprises everywhere: How can I best get my company into shape for the digital future?
A complete compressed air system assessment should provide detailed information on both the supply and demand sides of the system. The supply-side refers to the equipment supplying compressed air – the air compressor, dryers, filters, piping and storage tanks.  The purpose of this article is to illustrate what information we believe a factory should receive from a supply-side system assessment and more importantly – what information a plant should always know about their compressed air system.
A newly constructed ethanol plant experienced control gap issues shortly after comissioning.  This article discusses the cause of the issue and how the problem was solved.