Industry News

Centrifugal Air Compressor Controls and Sizing Basics

By Tim Dugan, P.E. President, Compression Engineering Corporation

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.

Centrifugal air compressor flow rate is relatively constant at a given pressure and inlet temperature, at full load. In common screw air compressor parlance, they are considered “base-load”, meaning they should be running at full capacity all the time. That is a simplified, but correct view of how one should see most applications of centrifugal air compressors, if in fact there are properly controlled screw air compressors used as “trim”, and their inlet conditions are relatively constant. However, in most actual systems with centrifugal air compressors, they are not running base-loaded, and inlet conditions change dramatically throughout the seasons. Sometimes, centrifugal air compressors are in a centrifugal-only system, where they are oversized and at a poor part-load efficiency point, with one running and one in back-up. Or there are multiple units running at different parts of a large plant air system, running independently, sometimes efficiently and sometimes not. Or they are in mixed screw / centrifugal systems where they are running in parallel with the screw air compressors, also at part load. In our view, a common reason for these less than optimal applications is the lack of knowledge of controls and maintenance by most vendors, technicians and engineers who are more familiar with screw air compressors.

In this article, I aim to describe the essential way a centrifugal air compressor is controlled and how to size one properly. In order to do so, I need to cover some basics, as follows:

  1. Describe centrifugal air compressor basics.
  2. Describe a centrifugal air compressor’s curve.
  3. Describe centrifugal air compressor control.
  4. Discuss implications for air compressor sizing.

Centrifugal Air Compressor Basics

A centrifugal air compressor develops pressure by accelerating a gas from the center of the impeller, through the “impeller”, by centrifugal force, and then slowing it down in a “diffuser” through expansion. The velocity energy is converted into pressure energy (by Bernoulli’s principle, pressure is inversely proportional to velocity squared). See Figure 1.

Centrifugal Air Compressor Basics

Read More »

Posted in Educational, Industrial Air Compressors | Tagged , , | Comments Off on Centrifugal Air Compressor Controls and Sizing Basics

Industrial Air Compressor Distributor in Riverside County

Q Air-California is an authorized and reliable distributor of industrial air compressor systems, parts and accessories in Riverside County.

Q Air-California has built a strong reputation as the leading provider of all types and brands of air compressors in the country. We supply and distribute air compressor systems and parts to all industries including Aerospace, Packaging, Hospitals, Refineries, Food & Beverage and more.

Industrial Air Compressor Distributor in Riverside County

We specialize in distribution and supply of high quality industrial air compressor systems and air compressor products such as:

Industry choice air compressors

Sourcing industrial air compressors in the market can be a daunting task especially when there are a vast range of different types, brands and performance specifications out there. Our knowledge and experience in the air compressor industry enables us to provide you with the best industry choice air compressor systems and parts that meet your production requirements.

Engineering service and support

Not only do we supply best quality air compressor systems and parts to you, we also extend our engineering support to ensure the air compressor systems function at optimal level. Our full-time, highly trained technicians offer technical support including a full range of service and repair for all air compressor equipment.

Excellent customer service

At Q Air-California, we value our customers. We’re committed to providing you with excellent customer service experience at all times. We listen intently to your needs and specifications so as to accommodate them in delivering high quality air compressor systems that meets or exceeds your expectations.

Request a Quote

For more information about our air compressor systems and parts supply and distribution in Riverside County or to request a quote, contact us online or call our office at 888.311.7247.

Posted in Industrial Air Compressors | Tagged , , | Comments Off on Industrial Air Compressor Distributor in Riverside County

Key Considerations for Installing Centrifugal Air Compressors

Compressed Air Best Practices® (CABP) Magazine recently caught up with Rick Stasyshan, Compressed Air and Gas Institute’s (CAGI) Technical Consultant, and Ian MacLeod of CAGI member company,

CABP: Where is a good place to start when considering the installation of a centrifugal compressor system?

CAGI: The installation of any type of air compressor requires proper planning as well as adherence to the manufacturer’s recommended guidelines.

Planning a Centrifugal Air Compressor Installation

CABP: What are some of the areas to be considered during this planning process?

CAGI: The end user or customer should convene a pre-installation meeting with the user site managers, site maintenance staff, the compressor manufacturer’s technical representative(s), and the contractors responsible for installation.

CABP: Actual location of the equipment can impact system performance. What are your thoughts on this point?

CAGI: The reality is proper location selection can assure the user of receiving maximum value from their system over its economic life.

CABP: And what about future service and maintenance considerations?

CAGI: All compressors will require periodic inspection and maintenance.

CABP: Do centrifugal compressors require “special foundations”?

CAGI: No they do not. The foundation should be free of any external sources of vibration created by nearby equipment.
Major Considerations for Inlet Air

CABP: How does ambient temperature impact centrifugal compressor operation?

CAGI: The ambient environment can adversely impact a compressor system’s reliability, and centrifugal compressor systems are not an exception.

CABP: I assume when you mention adequate ventilation, you are referring to inlet air. What are some of the considerations?

CAGI: Yes, once the location is determined and finalized, it is time to consider connection points.
Designing Ventilation for Centrifugal Air Compressors

CABP: In our discussions on the equipment, you had mentioned bypass piping as part of the scope of supplier equipment. Is now a good time to discuss this installation?

CAGI: Most centrifugal compressors have a shipped loose bypass silencer. The silencer can be installed indoors or outdoors.

CABP: Assuming the compressor is now installed, leveled, and we have inlet air, I guess it is time to connect to the plant’s demand side. What are your thoughts?

CAGI: The discharge piping has to be rated according to the expected compressor pressure and temperature.

CABP: Compressor performance depends on adequate cooling of the compressors. Can you share your thoughts on this subject?

CAGI: Water quality is equally as important as air quality. Consult with the compressor representative regarding water quality and quantity requirements.

CABP: Please provide some commentary on the electrical hook-up.

CAGI: The design and installation of electrical systems should be performed by qualified personnel and must meet all applicable electrical codes.

CABP: Any closing thoughts?

CAGI: We recommend users always thoroughly review and adhere to the manufacturer’s instructions for a safe and successful installation.

CABP: Where to get information concerning centrifugal compressors and other information available from CAGI.

CAGI: CAGI’s Centrifugal Compressor Section members include Atlas Copco, Cameron, FS Elliott and Ingersoll Rand.

Read More »

Posted in Industrial Air Compressors | Tagged , , | Comments Off on Key Considerations for Installing Centrifugal Air Compressors

4 Compressed Air System Lessons to Be Aware Of

Compressed air systems are an integral part of many industrial applications. Because of this, it’s important to understand how they operate & what to be aware of in order to help you make more informed decisions. With several years of experience to date, we’d like to share with you some of our most important lessons learned along the way.

Compressed Air System Lessons

Lesson 1 – Just because the compressor is off does not mean the purge will stop.

If a compressor turns off for any reason, but the dryer is operating on a fixed cycle with no dew point control, then the purge will usually still continue to be fed from other compressors. While the purge cycle continues uninterrupted, the minute the desiccant has been regenerated an uncontrolled air dryer will continue to consume purge air & effectively waste a significant amount of compressed air even though no air is flowing through.

Lesson 2 – Air dryers use up the most compressed air.

Lesson 1 leads us directly into lesson 2: that air dryers use up the most compressed air in the operation’s entire compressed air system. This definitely holds true for lightly loaded systems where both the compressor and dryer are larger than the actual average loading size.

Lesson 3 – Most of the time it’s better to repair than purchase new.

After performing several air & energy audits in Southern California, we’ve learned that even in extreme scenarios where it might seem the most obvious choice is to replace the system with a new one, it is actually much more cost effective to repair a fault compressed air system than it is to purchase a new one.

Lesson 4 – Regular testing is good practice.

It should almost go without saying, but it’s important to regularly test purge flow to prevent situations in which purge flows are much higher than the rating of the dryer, which would cause significant amount of waste. If the ball valve is misadjusted for any reason, then it will cause the gauge to go out of calibration & this is easily overlooked if the system is not tested regularly.

Q Air-California Can Take Your Compressed Air System to the Next Level!

Having performed compressed air & energy audits for a variety of different industries, we have the knowledge and experience to help you find overlooked areas that may be wasting your time, energy, and resources.

Posted in Educational, Industrial Air Compressors | Tagged , , | Comments Off on 4 Compressed Air System Lessons to Be Aware Of

Compressed Air Central Key Performance Indicators (KPI’s)

Quite often the typical variability in compressed air flow demand does not proportionately translate into power reductions at the air compressors. This can be a result of numerous problems with the compressed air supply system. It is important to understand the supply-side’s ability to respond to the demand-side of the compressed air system. If the air compressors, on the supply-side, are not able to translate flow reductions into energy savings, implementation of demand reduction projects should be re-evaluated.

How often are products pitched to plant personnel and touted as energy-saving because they can reduce the use of compressed air in terms of flow (scfm) and/or pressure (psig)? There are many very valid products and techniques (which we deploy during our audits) able to reduce compressed air demand requirements.

Compressed Air KPI's

 

Reducing compressed air use, however, will not turn into energy-savings at the air compressors in a large percentage of installations we visit. Why? There are many potential reasons. The air compressors may not have the local controls permitting them to use less energy at partial loads. Or, the air compressors may be working simultaneously – all at less than optimal points in their efficiency curves.

Compressed air demand is always changing in plants. This is why the use of a central controller for the system can deliver high ROI’s with benefits extending to reliability and compressed air quality enhancements. A central control system is able to automatically respond to changes in compressed air system dynamics and provide the plant with Key Performance Indicators.

Instruments Deliver 5 Key Performance Indicators

A compressed air monitoring system will enable the plant to track air system performance and energy efficiency levels on an ongoing basis so energy savings achieved in the proposed projects can be maintained over time. The primary elements of such a monitoring system such as the location of recommended flow, kW, and pressure meters are listed below. At installations such as the one we’ve profiled in this article, we also review where to install monitoring points in the air compressor room(s) and in the factory to optimally control the air compressors with a central control system. The Key Performance Indicators to monitor are pressure, flow, dew point, and individual compressor power.

The recommended elements instruments, for this project, to support a comprehensive monitoring system included:

  • (6) kW demand meters on each individual compressor — $1,500 each for a total of $9,000
  • (12) PSI transducers (7 in the compressor room and 5 out in the plant) — $200 each for a total of $2,400
  • (1) Compressed air flow meter — $3,000 each
  • (1) Dew Point Demand Meter — $2,500 each
  • (2) Data Integrators — $5,000 each for a total of $10K

The total price tag for the monitoring system equipment was $26,000. Installation cost were projected at $20,000 for a total cost of $46,000. This instrumentation would then provide the Central Compressor Control System with the information required to deliver these Key Performance indicators:

  1. Flow levels over time (e.g., upward trends could indicate increased leak levels)
  2. Individual compressor kW readings (e.g., upward trends could indicate compressor malfunction)
  3. Basic System Efficiency over time — Specific Power defined as Flow / Total kW demand (e.g., upward trends indicate loss in efficiency)
  4. Dew Point Levels (e.g., upward trends indicate increased moisture levels and possible air treatment equipment malfunction)
  5. System Pressure (e.g., erratic pressure levels could indicate insufficient air supply capacity; excessively low levels could be harbingers of production equipment failure)

Read More »

Posted in Educational, Industrial Air Compressors | Tagged , , | Comments Off on Compressed Air Central Key Performance Indicators (KPI’s)

Centrifugal Air Compressor Basics

Industrial Air Compressor Capacity Definitions

Following are some clarifying definitions of terms used, and often misused, to define capacity or flow in centrifugal compressors.

Centrifugal Air Compressor Basics

Capacity is the quantity of air at which the compressor will operate at a specific discharge pressure. For all industrial compressors, capacity is rated at the conditions of pressure, temperature and moisture content existing at the compressor inlet flange. The basic reference for all discussion on air flow relates back to mass flow. All definitions and conversions are directly related to conservation of mass flow through the compressor.

Mass flow (lb/min or kg/hr) is a specific value independent of the air inlet conditions. The compressor functions on how much mass flow (lb/min) flows through the machine. For this reason it is the best means of comparing one flow value to another. The problem with using it all the time is that compressor manufacturers size compressors on actual inlet air volume flow. This is done because the compressor size is a function of the actual inlet volume it can hold.

  • lb/min wet is the mass of air including the water vapor in the air.
  • lb/min dry is the mass of the air without the water content i.e. dry air (0% relative humidity)

CFM (cubic feet per minute) (M3/min) is a volumetric measurement not dependent on inlet conditions such as temperature, pressure and humidity. When working with centrifugal compressors, this should be clarified (when working with all compressor types, this should also be clarified).

ACFM (actual cubic feet per minute) (M3/min) is the actual inlet air delivered at the discharge flange. ACFM represents useful air and is independent of the seal losses through the machine. The commonly used value for seal losses with carbon seals is about 1%.

ICFM (inlet cubic feet per minute) (or M3/hr) is a measure of the air entering the compressor referred back to inlet conditions. ICFM is the most common method of determining centrifugal compressor selection. CAGI and PNEUROP often rate centrifugal compressors in icfm. The only difference between icfm and acfm is that acfm is measured at the compressor discharge flange, whereas icfm is measured at the compressor inlet flange or at the discharge flange and corrected for seal losses. Some centrifugal compressors may have other air losses between the inlet and discharge flanges.

Unlike positive displacement type compressors where icfm is almost always significantly higher than acfm and with the exception of such small items as potential seal leakage, icfm and acfm are often used interchangeably with regard to capacity flow ratings.

Read More »

Posted in Uncategorized | Comments Off on Centrifugal Air Compressor Basics

Ventura Industrial Air Compressor Repair Service

Ventura Industrial Air Compressor Repair Service

Q-Air California is the premier Ventura industrial air compressor repair servicing industrial air compressors across Ventura County, California.

Effective and efficient repair

We strive to help keep manufacturing and processing lines running smoothly and continuously. Our experienced and dedicated team of technicians works around the clock to ensure you get top-quality industrial air compressor repair that you deserve. We also perform an energy audit for your industrial air compressor systems to help you reduce operating cost as well as eliminating downtime.

Air compressor parts and supplies from top brands

Q-Air supplies and distributes air compressor parts and systems from the most popular brands in the market. We specialize in the repair of old or obsolete air compressor components including replacement parts, pumps, and accessories.

We service every industry

Our Ventura industrial air compressor repair service extend to various manufacturing industries in such as plastics, textiles, glass, metal, tobacco, HVAC, wind power, chemicals, rubber, automotive, steel, leather, food, and water treatment plants. We use the latest technology and industry standards methods to assess and repair your air compressors to ensure that they work effectively.

24-hour Ventura industrial air compressor repair service

We also offer 24-hour emergency service through our team of experienced, well-trained technicians and engineers to help you keep your production running.

Let our team of professionals perform effective quality repairs for your industrial air compressors so as to keep your facility running. Our highly dedicated and knowledgeable technicians will demonstrate to you how perfect industrial air compressor repair can go a long way toward enhancing the performance and overall productivity of the air compressors.

Q-Air California is the leader in repair for industrial air compressors in the whole of California. We provide you with the peace of mind that comes from knowing that the repaired parts will work as intended. We are committed to exceptional customer service by providing value to our customers.

Request A Quote for Ventura Industrial Air Compressor Repair

Request a flat-rate quote for any type of Ventura industrial air compressor repair service by completing the form below.

Contact us for more information on the cost of Ventura industrial air compressor repair service. Talk to us online or call our toll-free line 888-311-7247

Posted in Industrial Air Compressors | Tagged , , | Comments Off on Ventura Industrial Air Compressor Repair Service

Industrial Air Compressor Repairs Orange County

Q Air-California has been servicing industrial air compressors for manufacturing and industrial plants across Orange County, California for decades.

We strive to help keep manufacturing and processing lines running smoothly and continuously. Our experienced and dedicated team of technicians works around the clock to ensure you get top-quality industrial air compressor repair that you deserve. We also perform an energy audit for your air compressor systems to help you reduce operating cost as well as eliminating downtime.

Q-Air supplies and distributes air compressor parts and systems from the most popular brands in the market. We specialize in the repair of old or obsolete air compressor components including replacement parts, pumps, and accessories.

Industrial Air Compressor Repairs Orange County

Our industrial air compressor repair service extend to various manufacturing industries in Orange County such as plastics, textiles, glass, metal, tobacco, HVAC, wind power, chemicals, rubber, automotive, steel, leather, food, and water treatment plants. We use the latest technology and industry standards methods to assess and repair your air compressors to ensure that they work effectively.

We also offer 24-hour emergency service through our team of experienced, well-trained technicians and engineers to help you keep your production running.

Let our team of professionals perform effective quality repairs for your industrial air compressors so as to keep your facility running. Our highly dedicated and knowledgeable technicians will demonstrate to you how perfect industrial air compressor repair can go a long way toward enhancing the performance and overall productivity of the air compressors.

Q Air-California is the leading repair experts for industrial air compressors in the whole of California. We provide you with the peace of mind that comes from knowing that the repaired parts will work as intended. We are committed to exceptional customer service by proving value to our customers.

Request A Quote for Industrial Air Compressor Repair Orange County

Request a flat-rate quote for any type of industrial air compressor repair service and we shall get back to you in the shortest time possible.

Contact us for more information on costs of air compressor repair in Orange County, California. Talk to us online or call our toll-free line 888-311-7247

Posted in Industrial Air Compressors | Tagged , , | Comments Off on Industrial Air Compressor Repairs Orange County

The Benefits of Regular Air Compressor Cleaning

When we think about compressed air, our imagination is of the big, loud, dirty, unreliable machine in the back corner of our facility. Many businesses around the world rely on compressed air, and an unreliable air compressor can mean stopping an entire facility, costing thousands of dollars in lost productivity and repair labor. The loud machine in the back corner is also a major energy consumer. In which many industry professionals refer to it as the “fourth utility.”

Moreover, one of the biggest causes of lost reliability and increased energy consumption in a compressor is varnish.

air compressor cleaning

What is Varnish?

Vanish is a term that broadly describes the by-products of lubricant degradation. Varnish also has a tendency to attract and hold onto harmful particulates, such as small pieces of wear metals, which can lead to wear and tear of lubricated components.

One of the biggest factors influencing lubricant degradation, leading to varnish creation, is heat. This means that a compressor running hot due to excessive varnish can fall into a trap of exacerbating the issue by reducing the rated life of fresh lubricants.

What Does Varnish Do To Your Air Compressor?

Common symptoms of a varnish issue include an increase in the operating temperature of the equipment, increased energy consumption, and decreased oil life. The sticky film that coats every internal surface can also lead to increased wear and decreased reliability of your equipment.

How Do You Prevent & Control Varnish?

Preventing and controlling varnish is a multi-step process that involves fully understanding not only your equipment, but also your oil. The first step is to perform regular oil analysis on the in-use lubricant. Oil analysis is an excellent tool for tracking lubricant degradation. While there are a number of lubricant properties to monitor, the three major watch points are the total acid number, metals count and viscosity at 40°C. While laboratories will look at other lubricant properties, the previously listed three are the major watch points.

In addition to regular oil analysis, a qualified oil analysis laboratory can also perform tests that are specific to identifying and quantifying varnish within a lubricant.

Additionally, sources of cavitation and electrostatic discharge should also be investigated if a system is experiencing varnishing of the oil. With so many different routes that can lead to varnish formation inside of equipment.

How Can You Clean Varnish?

One common method to eliminate varnish from the lubricant is through off-line filtration. Technologies such as electrostatic separators, cellulose media and balanced charge agglomeration has proven this is a viable technique.

Test Cases

A recent study performed by Isel showed that cleaning a compressor with heavy varnish buildup can result in an average energy savings of 3 to 5 percent, while also reducing operating temperatures by approximately 5°F. Not only will the reduced operating temperature help extend the life of future oil changes, but the reduced energy consumption can quickly pay off the cost of the cleaning.

Read More »

Interested in a Preventive Maintenance Program?
Q Air Can Help.

We specialize in industrial air compressor maintenance and offer emergency services as well. Preventive maintenance is one of the best ways to prevent unexpected failure or emergencies from arising. We service many counties throughout Southern California. For any sales inquiries, we may be contacted @ 888.311.7247.

Posted in Educational, Industrial Air Compressors | Tagged , , | Comments Off on The Benefits of Regular Air Compressor Cleaning

Compressed Air is an ENERGY STAR® at Ball Corporation

compressed air

Paying close attention to compressed air use is paramount for identifying potential energy-saving projects. The engineering team at Ball Corporation has been well aware of this fact for years. An active member in the Environmental Protection Agency’s ENERGY STAR® program, Ball Corporation scrutinizes manufacturing processes to maximize the energy efficiency of compressed air systems in each of its plants.

“Right Sizing” the High-Pressure Compressed Air System

Demand-reduction projects fed into supply-side opportunities, where Ball could reevaluate required capacities and drive big savings in energy. The effort started on the high-pressure system, where consistent throttling occurred due to oversized capacity.

Read Full Article »

Posted in Industrial Air Compressors | Tagged , , | Comments Off on Compressed Air is an ENERGY STAR® at Ball Corporation