Pneumatic conveying applications are critical to many facilities – when you can’t move material you can’t make or sell your product. Because of a historical lack of availability of specialized rental blowers and air compressors for pneumatic conveying, plants often either accepted the production outage or rented a more readily available two-stage, oil-free rotary screw air compressor designed for 90 to 150 psig plant air service that is very inefficient at the reduced pressures needed for pneumatic conveying.
Misapplying one of these plant air machines can result in an energy cost of three to 10 times greater than the appropriately applied positive displacement blower/single-stage oil-free rotary screw air compressor that is designed for pneumatic conveying applications – not to mention considerably higher rental rates and a larger footprint.
Here are examples of facilities that sustained production by renting positive displacement blowers/single-stage, oil-free rotary screw air compressors specifically built for positive pressure or vacuum pneumatic conveying applications.
Case Study No. 1 - Wrong Machine Purchased
A bakery purchased a blower to offload trucks based on design criteria of 800 cfm at up to 14.5 psig. Under these conditions, it was taking up to four hours to offload a truck. Further review revealed a higher pressure was required to speed up the offload process. A single-stage, oil-free rotary screw rental air compressor capable of 1,000 cfm at 29 psig with an onboard Variable Frequency Drive (VFD) was rented to validate the ideal compressor capability needed for the permanent installation. It was determined that at about 800 cfm and 17 psig they could reduce truck offload time to 1.5 hours. The bakery continued to utilize the rental machine to reduce offload times while the new machine was ordered and installed.
A bakery reduced truck offload time by replacing the wrong blower with a single-stage, oil-free rotary screw rental air compressor.
Case Study No. 2 - Production Shifted to Other Facilities
Historical flooding hit the Mississippi River in the Spring of 2019 and barge traffic was suspended. Some facilities were unable to move material in, or product out, and could not meet their contractual supply commitments. One plant creatively shifted production into another facility that was not impacted by the flooding; however, they lacked the infrastructure to offload the additional volume of railcars at that facility. The plant rented a positive displacement blower with an onboard VFD capable of 500 to 2,100 cfm at 9.8 psig for just a few months to continue moving material and increase throughput.
Case Study No. 3 – Compressed Air Airend Fails
A cement plant utilizing a single-stage, oil-free rotary screw air compressor to deliver 2,000 cfm at 25 psig to move raw material to the pre-heater tower experienced an unanticipated airend
failure. With no redundancy installed, the plant faced an outage while the airend was being repaired. The plant rented a single-stage, oil-free rotary screw air compressor with an onboard VFD that matched the performance of their failed machine and allowed production to continue for several weeks until the airend was returned and reinstalled.
When an air compressor airend failed, a cement company didn’t miss a beat by renting a single-stage, oil-free rotary screw air compressor.
Case Study No. 4 – Major Rotor Failure on Vacuum System
A ship was pulling into port with 8,000 tons of aluminum to be offloaded, but the offloading vacuum system had experienced a major failure that would take three to four weeks to resolve. The ship needed to be offloaded within the planned time interval. The needs were quantified at about 16,000 cfm at about 14 inches of mercury (Hg) vacuum pressure. The facility brought in six rented positive displacement blowers set up for vacuum operation and completed the offload in the timeframe needed.
Six rented positive displacement blowers allowed a ship to meet its offloading schedule when its offloading vacuum system unexpectedly failed.
Case Study No. 5 – Product Flow Not Meeting Expectations
The plant utilizes a fixed-speed blower in a closed-loop nitrogen system to maintain the integrity of PET granules being conveyed. They were not satisfied with the flow of the product and wanted to explore the effects of different flow rates. The plant rented a blower with an onboard VFD capable of closed-loop service between about 600 cfm to 1,500 cfm and up to 14.5 psig discharge pressure. This allowed them to prove there would be a benefit in upgrading their blower system.
A rental blower helped a plant verify the benefits of a blower system upgrade.
Rental Machines Well Worth the Investment
In all five cases, the customer rented machines ideally suited for their applications and the total cost of the rental was minuscule compared to the cost of a production interruption and at a
fraction of the total rental cost associated with renting the wrong machine.
Plants can rent equipment designed for peak efficiency in a wide range of pneumatic conveying applications and should never accept an extended outage or the wrong type of rental equipment. In addition, rental machines are a great way to experiment with the effects of varying flow on a process.
About Aerzen Rental
Specializing in temporary oil-free blower and compressor solutions under 50 psig, Aerzen Rental supplies 100% oil-free air solutions specializing in emergency response and long-term capital avoidance. Aerzen Rental provides best-in-class packages engineered for aggressive rental environments with on board VFDs, remote monitoring, and outdoor builds with sound attenuating enclosure as standard. From rental units for immediate deployment in the event of a production failure or shortfall, to operational leasing and contracting, Aerzen Rental is your expert partner. For more information About Aerzen Rental, contact Rental-USA@aerzen.com; tel: 1-844-400-AERZ (2379), or visit www.aerzenrentalusa.com.
All photos courtesy of Aerzen Rental.
To read similar articles on Pneumatic Conveying, please visit https://blowervacuumbestpractices.com/system-assessments/conveying.