A US-based can manufacturer recently upgraded their regenerative thermal oxidizer (RTO) in order to increase the maximum flow to the unit. The original oxidizer was designed and installed by Anguil back in 2015, with the intent to eventually upgrade. Anguil was able to successfully retrofit the equipment while overcoming the challenges that ensued. Through calculations and cost comparisons provided by Anguil, the customer was able to make practical, cost-effective, and environmentally friendly decisions to meet their specific needs.
Though the company has several Anguil units across the country, the retrofit was performed on an oxidizer with an upstream dust collector at a plant in the Midwest. An Anguil RTO can capture and destroy over 99% of the volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) emitted from the ovens and driers that are often used in can-making, coil coating, or metal painting. Emission destruction is achieved through the process of high-temperature thermal oxidation, converting the pollutants to carbon dioxide and water vapor while reusing the thermal energy generated to reduce operating costs.
“The plant had always planned to add additional lines so there was capacity built into the oxidizer and dust collector,” said Charlie Fields, an aftermarket application engineer at Anguil. The additional coating line the customer wished to add would send a total of 41,500 standard cubic feet per minute (SCFM) to the equipment, an increase of over 20,000 SCFM. Though the equipment was oversized initially to accommodate added flow, “the new production line would have exceeded the capacity of the RTO,” Fields continued.
To solve the issue, Anguil proposed multiple options to the can manufacturer. The first option was to install an additional, smaller oxidizer to handle the additional flow. However, this would have been costly to purchase and operate, as the plant would have had two different-sized RTOs. Furthermore, there was no available space to install a second RTO. The second option was to install a new, larger oxidizer to handle the total flow. However, removing an existing, working oxidizer and decommissioning it would be very expensive, along with the cost of buying and installing a much larger oxidizer. This option would have also presented production challenges as many can making plants cannot run without abatement systems in place. After collaboration between Anguil and the can maker, they decided on a third option.
The chosen solution was to install a concentrator wheel to concentrate the cool air streams to allow for more capacity in the RTO. The selected 15,000 SCFM concentrator wheel concentrates the flow from an existing dust collector and sends 1,500 SCFM of VOC-laden air to the RTO inlet. This ensures that all the lines can be used simultaneously. “We decided to run all the cool streams through the wheel to concentrate them and provide additional capacity now and in the future,” Fields said. “All the hot sources were run directly to the RTO.” The operating costs of this RTO/concentrator system were much lower than those of the other proposed systems: small/large RTO system and 1 large RTO system.
Once the retrofit decision was made, Anguil provided a turnkey project that included design, engineering, equipment selection, fabrication, installation, and startup services. With the purchase of an Anguil installation, the can manufacturer received a field service team to provide support and get the project finished and the equipment online.