You Don’t Need to Spend Thousands to Optimize Your Compressed Air System

There is no denying it, saving compressed air is a process.  This process often involves some type of energy audit or at the very least an evaluation of something going wrong with production and a way to improve it.  Many programs, consultants, and sales reps will devise a solution for the problem.

Often times the solution is to create a more efficient supply side of the compressed air system. The supply side is essentially everything within the compressor room or located in close proximity to the actual air compressor. While optimizing the supply side can amount to savings, many of these solutions and services can involve great expense, or capital expenditure processes.  These processes can often lead to delays and continued waste until the solution is in place.  What if there was a way to lower compressed air usage, save energy, solve some demand issues on the compressed air system and save some money while the capital expenditure process goes through for the larger scale project.

These solutions are a simple call, chat, email or even fax away. Our Application Engineers are fully equipped to help determine what points of your compressed air demand side can be optimized. The process generally starts with our Six Steps To Compressed Air Optimization.

6 Steps from Catalog

Once the points of use are evaluated the Application Engineer can give an engineered solution to provide some relief to the strain on your compressed air supply side.  For instance, an open copper pipe blow off that is commonly seen within production environments can easily be replaced with a Super Air Nozzle on the end of a Stay Set Hose that will still bend and hold position like the copper pipe does while also saving compressed air, reducing noise level, and putting some capacity back into the supply side of the compressed air system.

engineered nozzle blow offs
Engineered solutions (like EXAIR Intelligent Compressed Air Products) are the efficient, quiet, and safe choice.

One of the key parts to the solutions that we offer here at EXAIR is they all ship same day on orders received by 3 PM ET that are shipping within the USA. To top that off the cost is generally hundreds, rather than thousands (or tens of thousands) of dollars. Well under any level of a capital expenditure and can generally come in as a maintenance purchase or purchased quickly through the supply cribs.  Then, to take this one step further, when the EXAIR solution shows up within days and gets installed EXAIR offers for you to send in the blow off that was replaced and receive a free report on what level of compressed air savings and performance increases you will be seeing and provide a simple ROI for that blow off (though we would also encourage a comparison before a purchase just so you have additional peace of mind).

This amounts to saving compressed air and understanding how much air is being saved, adding capacity back into your supply side which will reduce strain on the air compressor, give the ability to increase production while the capital expenditure for the end solution of controls and higher efficiency on the supply side is approved to then save even more compressed air and energy.

The point is this, savings and efficiency doesn’t have to involve a capital expenditure, if that is the end game for your project that is great! Let EXAIR provide you a solution that you can have in house by the next business day to save money NOW and then put that savings towards another project. No matter the method, it all starts with a call, chat, email or fax.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Supply Side Review: Deliquescent Type Dryers

As mentioned in my post last week.  The supply side of compressed air systems within a facility is critical to production.  The quality of air produced by your compressor and sent to the demand side of the system needs to be filtered for both moisture and particulate.  One method to dry the air, that is the topic for this blog, is deliquescent type dryers.

These dryers operate like an adsorbent dryer such as a desiccant medium dryer.  The main variance is that the drying medium (desiccant) actually undergoes a phase change from solids to liquids.  Because of this the material is used up and cannot be returned to its original state for reuse.   The liquids formed by the desiccant dissolving in the removed water vapor are then filtered out of the air stream before it is passed on to the demand side of the air system.

There are many compounds that are used to absorb the moisture in the wet compressed air.  A few options are potassium, calcium, or sodium salts and many that contain a urea base.  The desiccant compound must be maintained at a minimum level for the dryer to contain enough media to successfully dry the air.

These dryers are generally a single tank system that is fed with compressed air from a side port near the bottom of the tank.  The air then travels up past drip trays where the desiccant and water mixture fall and ultimately ends up in the bottom of the tank.  The air then goes through a material bed that must be kept at a given level in order to correctly absorb the moisture in the air.  The dry air is then pushed out the top of the tank.

As the desiccant material absorbs the liquid from the compressed air flowing through the tank it falls onto the drip trays and then into the bottom of the tank where it is drained out of the system.  This process can be seen in the image below.

 

Deliquescent type compressed air drying system
How a deliquescent air dryer works – 1(VMAC Air Innovated, 2017)

 

The dew point that this style dryer is able to achieve is dependent on several variables:

  • Compressed air temperature
  • Compressed air pressure / velocity
  • Size and configuration of the tank
  • Compression of the absorption media
  • Type of absorption media and age of media

These dryers are simplistic in their design because there are no moving parts as well as easy to install and carry a low startup cost.

Some disadvantages include:

  • Dewpoint range 20°F – 30°F (Again this is according to the media used.)
  • Dissolved absorption material can pose a disposal issue as it may not be able to be simply put down a drain
  • Replacement of the absorption material

Even with disadvantages the ability to supply the demand side of a compressed air system for a production facility is key to maintaining successful operations.  If you would like to discuss any type of compressed air dryer, please contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

1 – Deliquescent Dryer Image: VMAC Air Innovated: The Deliquescent Dryer – https://www.vmacair.com/blog/the-deliquescent-dryer/

 

Intelligent Compressed Air: Membrane Dryers

A critical component on the supply side of your compressor system is the dryer. Atmospheric air contained within a compressed air system contains water vapor. The higher the temperature of the air, the more volume of moisture that air is capable of holding. As air is cooled, this water vapor can no longer be contained and this water falls out in the form of condensation. The temperature where this water will drop out is referred to as the dew point.

At a temperature of 75°F and 75% relative humidity, approximately 20 gallons of water will enter a 25HP compressor during a 24-hour period. As air is compressed, this water becomes concentrated. Since it’s heated during the compression process, this water stays in a vapor form. When this air cools further downstream, this vapor condenses into droplet form.

Moisture within the compressed air system can result in rust forming on the inside of the distribution piping, process failure due to clogged frozen lines in colder weather, false readings from instruments and controls, as well as issues with the point of use products installed within the system.

The solution to this problem is to install a dryer system. We’ve spent some time here on the EXAIR blog reviewing refrigerant dryers , desiccant dryers, deliquescent dryers, and heat of compression dryers. For the purposes of this blog, I’m going to focus on one of the newer styles on the market today: the membrane dryer.

Membrane Dryer

In a membrane dryer, compressed air is forced through a specially designed membrane that permits water vapor to pass through faster than the air. The water vapor is then purged along with a small amount of air while the rest of the compressed air passes through downstream. Generally, the dew point after the membrane dryer is reduced to about 40°F with even lower dew points also possible down to as low as -40°F!

With such low dew points possible, it makes a membrane dryer an optimal choice in outdoor applications that are susceptible to frost in colder climates. Membrane dryers also are able to be used in medical and dental applications where consistent reliability is critical.

A membrane dryer does not require a source of electricity in order to operate. The compact size makes it simple to install without requiring a lot of downtime and floor space. Since they have no moving parts, maintenance needed is minimal. Most often, this maintenance takes the form of checking/replacing filter elements just upstream of the membrane dryer. The membrane itself does need to be periodically replaced, an indicator on the membrane dryer will display when it needs to be changed. If particular instruments or processes in your facility are sensitive to moisture, a membrane dryer might be the best option.

However, there are some drawbacks to these types of dryers. They’re limited to low capacity installations, with models ranging from less than 1 SCFM up to 200 SCFM. This makes them more applicable for point-of-use installations than for an entire compressed air system. The nature in which the membrane dryer works necessitates some of the air to be purged out of the system along with the moisture. To achieve dew points as low as -40°F, this can equate to as much as 20% of the total airflow. When proper filtration isn’t installed upstream, oils and lubricants can ruin the dryer membrane and require premature replacement.

Make sure and ask plenty of questions of your compressor supplier during installation and maintenance of your system so you’re aware of the options out there. You’ll of course want to make sure that you’re using this air efficiently. For that, EXAIR’s wide range of engineered Intelligent Compressed Air Products fit the bill. With a variety of products available for same-day shipment from stock, we’ve got you covered.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

 

Membrane Dryer Schematic – From Compressed Air Challenge, Best Practices for Compressed Air Systems, Second Edition

 

Supply Side Review: Heat of Compression-Type Dryers

The supply side of a compressed air system has many critical parts that factor in to how well the system operates and how easily it can be maintained.   Dryers for the compressed air play a key role within the supply side are available in many form factors and fitments.  Today we will discuss heat of compression-type dryers.

Heat of compression-type dryer- Twin Tower Version

Heat of compression-type dryers are a regenerative desiccant dryer that take the heat from the act of compression to regenerate the desiccant.  By using this cycle they are grouped as a heat reactivated dryer rather than membrane technology, deliquescent type, or refrigerant type dryers.   They are also manufactured into two separate types.

The single vessel-type heat of compression-type dryer offers a no cycling action in order to provide continuous drying of throughput air.  The drying process is performed within a single pressure vessel with a rotating desiccant drum.  The vessel is divided into two air streams, one is a portion of air taken straight off the hot air exhaust from the air compressor which is used to provide the heat to dry the desiccant. The second air stream is the remainder of the air compressor output after it has been processed through the after-cooler. This same air stream passes through the drying section within the rotating desiccant drum where the air is then dried.  The hot air stream that was used for regeneration passes through a cooler just before it gets reintroduced to the main air stream all before entering the desiccant bed.  The air exits from the desiccant bed and is passed on to the next point in the supply side before distribution to the demand side of the system.

The  twin tower heat of compression-type dryer operates on the same theory and has a slightly different process.  This system divides the air process into two separate towers.  There is a saturated tower (vessel) that holds all of the desiccant.  This desiccant is regenerated by all of the hot air leaving the compressor discharge.  The total flow of compressed air then flows through an after-cooler before entering the second tower (vessel) which dries the air and then passes the air flow to the next stage within the supply side to then be distributed to the demand side of the system.

The heat of compression-type dryers do require a large amount of heat and escalated temperatures in order to successfully perform the regeneration of the desiccant.  Due to this they are mainly observed being used on systems which are based on a lubricant-free rotary screw compressor or a centrifugal compressor.

No matter the type of dryer your system has in place, EXAIR still recommends to place a redundant point of use filter on the demand side of the system.  This helps to reduce contamination from piping, collection during dryer down time, and acts as a fail safe to protect your process.  If you would like to discuss supply side or demand side factors of your compressed air system please contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Heat of compression image: Compressed Air Challenge: Drive down your energy costs with heat of compression recovery: https://www.plantservices.com/articles/2013/03-heat-of-compression-recovery/

 

Compressor Controls – Maximize Supply Side Efficiency

Air Compressor
Air Compressor and Storage Tanks

One of the most important aspect of an efficient compressed air delivery system is effective utilization of compressor controls. The proper use of compressor controls is critical to any efficient compressor system operation. In order to reduce operating costs, compressor controls strategies need to be developed starting with minimizing the discharge pressure. This should be set as low as possible to keep energy costs to a minimum.

The compressor system is designed with maximum air demand in mind. During periods of lower demand compressor controls are used to coordinate a reduction in output that matches the demand. There are six primary types of individual compressor controls:

  1. Start/Stop – This is the most basic control. The start/stop function will turn off the motor in response to a pressure signal.
  2. Load/Unload – The motor will run continuously, but the compressor unloads when a set pressure is reached. The compressor will then reload at a specified minimum pressure setting.
  3. Modulating – Restricts the air coming into the compressor to reduce compressor output to a specified minimum. This is also known as throttling or capacity control.
  4. Dual/Auto Dual – On small reciprocating compressors, this control allows the selection of either Start/Stop or Load/Unload.
  5. Variable Displacement – Gradually reduces the compressor displacement without reducing inlet pressure.
  6. Variable Speed – Controls the compressor capacity by adjusting the speed of the electric motor.

Most compressor systems are comprised of multiple compressors delivering air to a common header. In these types of installations, more sophisticated controls are required to orchestrate the compressor operation. Network controls link together each compressor in the system to form a chain. Usually, one compressor will assume the lead role with the others taking commands from the primary compressor. Some disadvantages of network controls include: only having the ability to control the compressors, cannot be networked with remote compressor rooms without a master control, and they generally only work well with compressors of the same brand due to microprocessor compatibility issues.

In more complicated systems, master controls can be used to coordinate all of the necessary functions to optimize the compressor system. Master controls have the ability to monitor and control all of the components within the system. The high-end master control systems utilize single point control logic with rate of change dynamic analysis in order to determine how the system will respond to changes. Changes on the demand side, supply side, or the ambient environment will all impact a compressor’s performance. An effective master control will be able to identify these changes and provide the most energy efficient response.

At the point of use, it’s always important to ensure you’re using a product that was engineered to reduce compressed air consumption. EXAIR’s line of Intelligent Compressed Air Products are available from stock to help you manage your overall operating costs.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

Images courtesy of thomasjackson1345 via Creative Commons License.

Proper Compressed Air Supply Plumbing Equals Success

EXAIR manufactures and stocks Super Air Knives in lengths ranging from 3”-108”. They’re designed to dramatically reduce compressed air usage when compared to similar blowoffs while still maximizing both force and flow. With an air entrainment ratio of 40:1, it’s the ideal solution for a variety of applications that necessitate a wide, laminar sheet of high velocity airflow.

I recently worked with a customer who makes wooden pallets. They were using a Model 110048 48” Super Air Knife to remove sawdust from the pallets prior to stacking them. When the grooves are cut into the pallet to accommodate the forks from a forklift or pallet-jack, there’s a good amount of sawdust that remains on the pallet. They would prefer to not have sawdust all over the finished pallets that they send to customers, so they looked towards a Super Air Knife to provide a curtain of air capable of removing that sawdust just prior to stacking them.

They purchased the Model 110048, but after installing it they didn’t get the level of force they had been hoping for. After some initial discussions, we identified that the issue lied with the plumbing of the air supplied to the knife. A 48” Super Air Knife will need to be fed with compressed air to (3) of the ¼ NPT air inlets. This ensures that an adequate volume of air is fed to the full length of the knife, keeping a consistent airflow.

Not only had they been plumbing compressed air to just (1) air inlet, but they were also using a restrictive quick-disconnect fitting. The I.D. of a quick connect fitting restricts the overall volume of air that can be passed through it. Length of the pipe or hose is also critical as the diameter of the pipe will need to be larger for longer runs or greater volumes. Accompanying any Super Air Knife is our Installation & Maintenance Guide which outlines the necessary requirements for each available length that we have available as well as how many air inlets need to be supplied with compressed air.

SAK pipe sizing

To confirm that air supply was the issue, they installed a pressure gauge directly at the air inlet to the knife. Line pressure was around 90 PSIG, but when they opened the valve and supplied air to the knife the pressure gauge dropped all the way to 35 PSIG. We’ve talked about pressure drop before here on the EXAIR Blog, the only way to confirm this is to take a pressure reading directly at the air inlet.

They removed the quick disconnect fitting, increased to a 1/2″ supply hose in place of 1/4″, and plumbed compressed air to each end and the center air inlet. On all Super Air Knives, compressed air inlets are available on either end as well as on the bottom. After fixing their plumbing, they noticed a dramatic increase in both force and flow and the pressure directly at the air inlet increased to 85 PSIG. The sawdust was easily blown off of the pallets and the customer was pleased that their pallets were free of sawdust.

sak pallet

At EXAIR, we stand by our products with the Unconditional 30 Day Guarantee. If you’ve just purchased a new product and aren’t seeing the results that you were hoping for give us a call. Our highly-trained team of Application Engineers is ready and standing by to investigate the application and provide support to help make sure you’re getting the most out of our products. Most of the times the solution is simple, but we won’t be satisfied until we find a resolution!

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

Understanding Compressed Air Supply Piping

An important component of your compressed air system is the supply piping. The piping will be the middle man that connects your entire facility to the compressor. Before installing pipe, it is important to consider how the compressed air will be consumed at the point of use.  You’ll also need to consider the types of fittings you’ll use, the size of the distribution piping, and whether you plan to add additional equipment in the next few years. If so, it is important that the system is designed to accommodate any potential expansion. This also helps to compensate for potential scale build-up (depending on the material of construction) that will restrict airflow through the pipe.

Air Compressor
Air Compressor and Storage Tanks

The first thing you’ll need to do is determine your air compressor’s maximum CFM and the necessary operating pressure for your point of use products. Keep in mind, operating at a lower pressure can dramatically reduce overall operating costs. Depending on a variety of factors (elevation, temperature, relative humidity) this can be different than what is listed on directly on the compressor. (For a discussion of how this impacts the capacity of your compressor, check out one of our previous blogs – Intelligent Compressed Air: SCFM, ACFM, ICFM, CFM – What do these terms mean?)

Once you’ve determined your compressor’s maximum CFM, draw a schematic of the necessary piping and list out the length of each straight pipe run. Determine the total length of pipe needed for the system. Using a graph or chart, such as this one from Engineering Toolbox. Locate your compressor’s capacity on the y-axis and the required operating pressure along the x-axis. The point at which these values meet will be the recommended MINIMUM pipe size. If you plan on future expansion, now is a good time to move up to the next pipe size to avoid any potential headache.

After determining the appropriate pipe size, you’ll need to consider how everything will begin to fit together. According to the Best Practices for Compressed Air Systems from the Compressed Air Challenge, the air should enter the compressed air header at a 45° angle, in the direction of flow and always through wide-radius elbows. A sharp angle anywhere in the piping system will result in an unnecessary pressure drop. When the air must make a sharp turn, it is forced to slow down. This causes turbulence within the pipe as the air slams into the insides of the pipe and wastes energy. A 90° bend can cause as much as 3-5 psi of pressure loss. Replacing 90° bends with 45° bends instead eliminates unnecessary pressure loss across the system.

Pressure drop through the pipe is caused by the friction of the air mass making contact with the inside walls of the pipe. This is a function of the volume of flow through the pipe. Larger diameter pipes will result in a lower pressure drop, and vice versa for smaller diameter pipes. The chart below from the Compressed Air and Gas Institute Handbook provides the pressure drop that can be expected at varying CFM for 2”, 3”, and 4” ID pipe.

ccfdfcfdddfcvgdsdfzxcv.png
Air Pressure Drop

To discuss your application and how an EXAIR Intelligent Compressed Air Product can help your process, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer
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Twitter: @EXAIR_JS

 

Images Courtesy of  the Compressed Air Challenge and thomasjackson1345 Creative Commons.