A large-scale provider of dog and cat foods needed a solution to their emissions control problem. The dog food that they were producing was creating odors that needed to be destroyed. The company evaluated several options, narrowing it down to a rotary valve regenerative thermal oxidizer (RTO), because it came with a guarantee.

According to Jason Valia, a regional sales manager for Dürr Systems Inc., Plymouth, Mich., the client needed to be assured that they would have no further problems once the system was installed. "We had to guarantee that if the odors coming from the plant weren't destroyed above and beyond the environmental regulations we'd become liable for it, and we'd have to pay a penalty and repair or create a new oxidizer to get them complete odor destruction," he said. "There were three or four other companies that they were talking to but none were able to offer these guarantees."

Located in Southern California, the pet food manufacturer had a very high exhaust stream coming from different stages of the process that would have incurred extremely high operating costs were they to capture all the exhaust. By modifying the design of the capture system in the plant, Valia's group was able to reduce the exhaust flow, and ensure that all of the odor coming from the plant was captured and directed to the regenerative thermal oxidizer.

"We did all the permitting and all the ductwork for the plant," said Valia. "In addition, they had some dust getting into the exhaust duct. We designed a system with a bakeout, which allowed us to burn off these particulates."

Considering other options

The rotary valve RTO from Dürr Systems Inc. shown above was guaranteed to meet the performance specifications for the manufacturing plant.

The pet food manufacturer evaluated several different types of systems, including a two-tower RTO and a traditional three-tower RTO. After considering the advantages and disadvantages of each, they chose a compact rotary valve RTO design that included a continuous purge feature, which ensured that no untreated emissions would escape the oxidizer.

According to Valia, because the client did not have a very high concentration of organics, "we were able to include our natural-gas induction system, which reduces gas consumption and minimizes NO_X generation in the oxidizer. It's very efficient in terms of energy consumption." PE