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/

 

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/

 

Opportunities To Save On Compressed Air

If you’re a regular reader of the EXAIR blog, you’re likely familiar with our:

EXAIR Six Steps To Optimizing Your Compressed Air System

This guideline is as comprehensive as you want it to be.  It’s been applied, in small & large facilities, as the framework for a formal set of procedures, followed in order, with the goal of large scale reductions in the costs associated with the operation of compressed air systems…and it works like a charm.  Others have “stepped” in and out, knowing already where some of their larger problems were – if you can actually hear or see evidence of leaks, your first step doesn’t necessarily have to be the installation of a Digital Flowmeter.

Here are some ways you may be able to “step” in and out to realize opportunities for savings on your use of compressed air:

  • Power:  I’m not saying you need to run out & buy a new compressor, but if yours is
    Recent advances have made significant improvements in efficiency.

    aging, requires more frequent maintenance, doesn’t have any particular energy efficiency ratings, etc…you might need to run out & buy a new compressor.  Or at least consult with a reputable air compressor dealer about power consumption.  You might not need to replace the whole compressor system if it can be retrofitted with more efficient controls.

  • Pressure: Not every use of your compressed air requires full header pressure.  In fact, sometimes it’s downright detrimental for the pressure to be too high.  Depending on the layout of your compressed air supply lines, your header pressure may be set a little higher than the load with the highest required pressure, and that’s OK.  If it’s significantly higher, intermediate storage (like EXAIR’s Model 9500-60 Receiver Tank, shown on the right) may be worth looking into.  Keep in mind, every 2psi increase in your header pressure means a 1% increase (approximately) in electric cost for your compressor operation.  Higher than needed pressures also increase wear and tear on pneumatic tools, and increase the chances of leaks developing.
  • Consumption:  Much like newer technologies in compressor design contribute to higher efficiency & lower electric power consumption, engineered compressed air products will use much less air than other methods.  A 1/4″ copper tube is more than capable of blowing chips & debris away from a machine tool chuck, but it’s going to use as much as 33 SCFM.  A Model 1100 Super Air Nozzle (shown on the right) can do the same job and use only 14 SCFM.  This one was installed directly on to the end of the copper tube, quickly and easily, with a compression fitting.
  • Leaks: These are part of your consumption, whether you like it or not.  And you shouldn’t like it, because they’re not doing anything for you, AND they’re costing you money.  Fix all the leaks you can…and you can fix them all.  Our Model 9061 Ultrasonic Leak Detector (right) can be critical to your efforts in finding these leaks, wherever they may be.
  • Pressure, part 2: Not every use of your compressed air requires full header pressure (seems I’ve heard that before?)  Controlling the pressure required for individual applications, at the point of use, keeps your header pressure where it needs to be.  All EXAIR Intelligent Compressed Air Product Kits come with a Pressure Regulator (like the one shown on the right) for this exact purpose.
  • All of our engineered Compressed Air Product Kits include a Filter Separator, like this one, for point-of-use removal of solid debris & moisture.

    Air Quality: Dirty air isn’t good for anything.  It’ll clog (and eventually foul) the inner workings of pneumatic valves, motors, and cylinders.  It’s particularly detrimental to the operation of engineered compressed air products…it can obstruct the flow of Air Knives & Air Nozzles, hamper the cooling capacity of Vortex Tubes & Spot Cooling Products, and limit the vacuum (& vacuum flow) capacity of Vacuum Generators, Line Vacs, and Air Amplifiers.

Everyone here at EXAIR Corporation wants you to get the most out of your compressed air use.  If you’d like to find out more, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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EXAIR Air Nozzles – Here’s Their Simple ROI

Return on Investment, or ROI, is the ratio of profit over total investment.  Many people use it to check stocks, financial markets, capital equipment, etc.  It is a quantitative way in determining the validity for an investment or project.   You can use the ROI value to give a measurable rate in looking at your investment.

For a positive ROI value, the project will pay for itself in less than one year.  Any negative values would represent a high-risk investment.  In this blog, I will compare the ROI when replacing a ¼” NPT open pipe with a model 1122 2” Flat Super Air Nozzle.  Let’s start by looking at Equation 1 to calculate the Return on Investment:

Equation 1:  ROI = (Total annual savings – Total Project Cost) / Total Project Cost * 100

The second part of the equation, Total Project Cost, is the cost of the nozzles plus the labor to install them onto the machine.  The model 1122, 2” Flat Super Air Nozzle, has a price of $70.00 each.  The cost of a ¼” NPT Pipe that is roughly 2” long is around $1.50 each.  What a difference!  How could EXAIR been in business for over 35 years?  Let’s continue on with the Return on Investment…

The amount of time required to install the nozzles to the end of a pipe is 1/2 hour (generously).  The labor rate that I will use in this example is $75.00 per hour (you can change this to your current labor rate).  The labor cost to install a nozzle is $35.00.   The Total Project Cost can be calculated as follows: ($70 – $1.50) + $35.00 = $103.50.  The next part of the equation, Total annual savings, has more complexity in the calculation, as shown below.

As a reference, EXAIR Super Air Nozzles for compressed air would be considered like LED light bulbs for electricity.  The open pipes and tubes would represent the incandescent light bulbs.  The reason for this parity is because of the amount of energy that the EXAIR Super Air Nozzles can save.  While LED light bulbs are a bit more expensive than the incandescent light bulbs, the Return on Investment has a high percentage, or in other words, a short payback period.  On the other hand, the open pipe is less expensive to purchase, but the overall cost to use in your compressed air system is much much higher.  I will explain why.

To calculate the Total Annual Savings, we need to generate a blow-off scenario (You can use your actual values to calculate the ROI for your project).  In this example, I will compare the ¼” NPT open pipe to the 2” Flat Super Air Nozzle.  (The reason behind this comparison is that the model 1122 can screw directly onto the end of the 1/4” NPT pipe.)   The amount of compressed air used by a 1/4” NPT open pipe is around 140 SCFM (3,962 SLPM) at 80 PSIG (5.5 Bar).  The model 1122 has an air consumption of 21.8 SCFM (622 SLPM) at 80 PSIG (5.5 Bar).  At an electrical rate of $0.08 per Kilowatt-hour, we see that the cost to make compressed air is $0.25 per 1000 standard cubic feet, or $0.25/1000SCF.  (Based on 4 SCFM per horsepower of air compressor).

To calculate an annual savings, let’s use a blow-off operation of 8 hours/day for 250 days a year.   Replacing the ¼” NPT open pipe with a model 1122, it will save you (140 SCFM – 21.8 SCFM) = 118.2 SCFM of compressed air.  To put this into a monetary value, the annual savings will be 118.2 SCFM *$0.25/1000SCF * 60 Min/hr * 8hr/day * 250 day/yr = $3,546/year.  Now if you have more than one blow-off spot in your facility like this, imagine the total amount of money that you would save.

With the Total Annual Cost and the Project Cost known, we can insert these values into Equation 1 to calculate the ROI:

ROI = (Total annual savings – Total Project Cost) / Project Cost * 100

ROI = ($3,546 – $103.50) / $103.50 * 100

ROI = 3326%

With a percentage value that high, we are looking at a payback period of only 9 days.  You may look at the initial cost and be discouraged.  But in a little over a week, the model 1122 will have paid for itself.  And after using it for just 1 year, it will save your company $3,546.00.  Like with any great idea, the LED light bulb clicked on in my mind.  What could be the total savings if you looked at all the blow-off applications in your facility?

EXAIR Nozzles

In my experience, a loud blowing noise from your equipment is generally coming from an open pipe or tube.  With these “cheap” ways to blow compressed air, it will cost your company a lot of money to use as shown in the example above.  If you would like to team up with EXAIR to set up ways to increase savings, improve productivity, and increase safety, you can contact an Application Engineer to get started.  It can be as simple as screwing on a Super Air Nozzle.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Compressed Air System Maintenance

When I was seventeen my grandfather took me to a used are dealership and helped me buy my first car. It wasn’t anything special, as it was a 1996  Chevrolet Lumina. It had its fair share of bumps and bruises, but the bones were solid. We took it home and he taught me how to do all the basics, we changed the oil, oil filter, air filter, brakes, pretty much every fluid we could, we changed.

2100756931_c7416f9bb9_z.jpg

You see my grandfather retired from Ford Motor Company after 50+ years of service. And he always said, “If you treat it right, it will treat you right.”; and I’ve lived by that ever since.

Just like a car, air compressors require regular maintenance to run at peak performance and minimize unscheduled downtime. Inadequate maintenance can have a significant impact on energy consumption via lower compression efficiency, air leakage, or pressure variability. It can also lead to high operating temperatures, poor moisture control, and excessive contamination.

Most problems are minor and can be corrected by simple adjustments, cleaning, part replacement, or the elimination of adverse conditions. This maintenance is very similar to the car maintenance mentioned above, replace filters, fluids, checking cooling systems, check belts and identify any leaks and address.

All equipment in the compressed air system should be maintained in accordance with the manufacturers specifications. Manufacturers provide inspection, maintenance, and service schedules that should be followed strictly. In many cases, it makes sense from efficiency and economic stand-points to maintain equipment more frequently than the intervals recommended by the manufactures, which are primarily designed to protect equipment.

One way to tell if your system is being maintained well and is operating properly is to periodically baseline the system by tracking power, pressure, flow (EXAIR Digital Flowmeter), and temperature. If power use at a given pressure and flow rate goes up, the systems efficiency is degrading.

23666469499_3ac0e159df_z.jpg
Air Compressor

Types Of Maintenance

Maintaining a compressed air system requires caring for the equipment, paying attention to changes and trends, and responding promptly to maintain operating reliability and efficiency. Types of maintenance include;

  1. Poor Maintenance – Sadly, some plants still operate on the philosophy, “If it isn’t broke, don’t fix it.” Due to the lack of routine preventative maintenance, this practice may result in complete replacement of an expensive air compressor as well as unscheduled and costly production interruptions.
  2. Preventive  Maintenance – This type of maintenance can be done by plant personnel or by an outside service provider. Usually, it includes regularly scheduled monitoring of operating conditions. Replacement of air and lubricant filters, lubricant sampling and replacement, minor repairs and adjustments, and an overview of compressor and accessory equipment operation.
  3. Predictive  Maintenance – Predictive maintenance involves monitoring compressor conditions and trends , including operating parameters such as power use, pressure drops, operating temperatures, and vibration levels. The Right combination of preventive and predictive maintenance generally will minimize repair and maintenance costs.
  4. Proactive Maintenance – If a defect is detected, proactive maintenance involves looking for the cause and determining how to prevent a recurrence.

Unfortunately, even the best maintenance procedures cannot eliminate the possibility of an unexpected breakdown. Provisions should be made for standby equipment to allow maintenance with out interrupting production.

If you would like to discuss improving your compressed air efficiency or any of EXAIR’s engineered solutions, I would enjoy hearing from you…give me a call.

Jordan Shouse
Application Engineer
Send me an email
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Twitter: @EXAIR_JS

 

Images Courtesy of Tampere Hacklab

Flat Super Air Nozzles

 

EXAIR’s Flat Super Air Nozzles provide a 1” or 2” wide airstream with hard-hitting force. All of EXAIR’s Flat Super Nozzles adhere to OSHA Standard 29 CFR 1910.242(b) for dead-end pressure, providing a safe and efficient method of delivering a strong blast of air.

The flow and force from the Flat Super Air Nozzle is adjustable by regulating the pressure supplied to it as well as by installing different thicknesses of shims. Thicker shims provide more force and flow, while a thinner shim will reduce the force and flow as well as the overall air consumption. This makes the Flat Super Air Nozzle and ideal solution for applications that may require variable force for different applications.

The nozzles are also available in your very own Blowoff System that can be customized to fit the exact application. You have the ability to put together the best combination of nozzle, Stay Set Hose, and Magnetic Base to suit your needs. Available with either a single or dual Magnetic Base and any of our Stay Set Hoses, there’s many different possibilities. To begin:

  1. Select the Air Nozzle you’ll need.

EXAMPLE: HP1125SS 2” High Power Stainless Steel Super Air Nozzle

  1. Then select the length of Stay Set Hose. They’re available in lengths ranging from 6”-36”.

EXAMPLE: An HP1125SS with a 24” Stay Set Hose would be an HP1125SS-9224.

  1. Finally, you have the option to also select a Magnetic Base if necessary. These are available with either a one outlet Magnetic Base, or Two Outlet which would include (2) separate nozzles. For a single outlet, change the second digit of the “added on” dash number to a “3”. For a two outlet, change that number to a “4”.

 EXAMPLE: An HP1125SS with 24” Stay Set Hose and Dual Magnetic Base is a Model HP1125SS-9424.

bok_1122-9412_400

This allows you to customize the solution using ANY nozzle and ANY length Stay Set Hose, creating a custom solution for your application. If you’d like to talk about any of our Super Air Nozzles and which would be best for your application, feel free to give us a call.

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

 

About Air Compressors: Air Intake Best Practices

Take a second and think about where the air compressor is located within your facility.  It is more than likely not a major focal point displayed prominently in the floor layout. There is a better chance it is tucked away in a corner of the facility where operators seldom travel.  No matter the type of air compressor, it still has an intake where it pulls in the ambient air from around the compressor then sends it through some process and on the demand side of your compressed air system.  These intakes can easily be placed out of sight and out of mind especially in older facilities that were designed when compressors were loud and the piping layout kept them away from operators due to sound level restrictions.

Air Compressor
Antique Air Compressor (Not safe for use!)

That’s why your compressor manufacturer supplies a specific grade of air inlet/intake filter, and this is your first line of defense. If it’s dirty, your compressor is running harder, and costs you more to operate it.  If it’s damaged, you’re not only letting dirt into your system; you’re letting it foul & damage your compressor. It’s just like changing the air filter on your car, your car needs clean air to run correctly, so does your compressor and the entire demand side of your compressed air system.

According to the Compressed Air Challenge, as a compressor inlet filter becomes dirty, the pressure drop across the inlet increases, this is very similar to the point of use compressed air filters.  The inlet filter on the compressor is the only path the compressor has to pull in the air, when restricted the compressor can begin to starve for air very similar to if you only had a small straw to breath through and told to run a marathon.  A clogged inlet filter can give false symptoms to compressor technicians as well.

The effects can mimic inlet valve modulation which result in increased compression ratios. If we were to form an example based on a compressor with a positive displacement, if the filter pressure drop increases by 20″ H2O, a 5% reduction of the mass flow of air will be present without a reduction in the power being drawn by the compressor. This all leads to inefficiency which easily amounts to more than the cost to replace the depleted inlet air filter.

compressor
Compressed Air System

Where you place the filter is just as important as how often you replace it.  There are some tips to be used when mounting the inlet filter.

  1. The filter can be placed on the compressor, but the inlet pipe should be coming from an external area to the compressor room or even the building if possible. The inlet should be free from any contaminants as well.  Some examples that are easy to overlook are nearby condensate discharges, other system exhausts and precipitation.
  2. Depending on the type of compressor being used, a lower intake air temperature can increase the mass flow of air due to the air density.  A compressor that is lubricant injected is not susceptible to this due to the air mixing with the warmer lubricant before being compressed.

If you would like to discuss improving your compressed air efficiency or any of EXAIR’s engineered solutions, I would enjoy hearing from you…give me a call.

Jordan Shouse
Application Engineer
Send me an email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS

 

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