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.
Subscription users only!
Subscribers are able to view the whole article. Please register/subscribe (it's free and easy) to read all articles.