Robbie Manufacturing of Lenexa , KS is a leader in the production of printed shrink films, bags and pouches for a diverse range of demanding applications. In 2004 alone, the company was awarded a Good Buy award from Good Housekeeping magazine, achieved rigorous American Institute of Baking (AIB) certification and the highest award ( Best-in-Show for Wide Web ) possible from the Flexographic Technical Association (FTA).
Robbie is also interested in their reputation as a good neighbor. In 1991 and 1996, they invested in two catalytic oxidizers to control the EPA-regulated air emissions generated in their various processes. But when the company decided to purchase a new 10-color gearless press to increase capacity and capability, they knew they also needed to analyze the condition and operating costs of their two catalytic oxidizers.
Robbie contacted the supplier of the catalytic units, Anguil Environmental Systems, Inc. of Milwaukee , Wisconsin to analyze the most cost-effective and compliant way to replace the two aged systems. After an analysis, Anguil recommended replacement of the existing equipment with a single 25,000 Regenerative Thermal Oxidizer (RTO).
Though the catalytic units were a logical choice at the time of purchase, technological advances in the ensuing years had caused the RTO to become a viable alternative. Particularly important was the improvement in RTO cost-effectiveness generated in part by significant reductions in the cost of ceramic energy recovery media, along with improvements in heat transfer capability.
Robbie's and Anguil's objectives were to achieve destruction of 98% of the Volatile Organic Compounds (VOCs) in the airstream, to fit the system into the space occupied by the two catalytic systems and to accomplish the tear-out and subsequent installation in just six days.
The operation of the RTO is considerably different than the existing catalytic units. The oxidizer consists of two reinforced, insulated chambers filled with high temperature structured ceramic energy recovery media. The oxidizer utilizes two burners to maintain the oxidizer above the oxidation temperature. Located beside the energy recovery chambers are diverter valves and air duct plenum passages, which allow the process airflow to be diverted into and out of the oxidizer in either a clockwise or counter-clockwise mode. The directional mode is controlled by a PLC, which changes the direction of airflow at regular intervals to optimize system efficiency. Typical operational cycles range from 2 to 4 minutes.
In operation, solvent laden air (SLA) enters the oxidizer via an energy recovery chamber where the high temperature ceramic heat transfer media preheats the SLA prior to introduction into the oxidation chamber. As the SLA passes up through the bed, its temperature rapidly increases. After the chemical oxidation purification reaction occurs, the hot, clean, outgoing gas heats the exit energy recovery bed. In order to maintain optimum heat recovery efficiency of the bed, the SLA flow direction is switched at regular intervals by the automatic diverter valves on demand from the PLC control system. This periodic flow direction shift provides a uniform temperature distribution throughout the entire oxidizer.
With sufficient concentration of hydrocarbons in the process air stream, the heat energy content of the hydrocarbons will self-sustain the oxidation process, and no additional heat energy will be required.
Features that are specific to the RTO include:
• High volumetric turn-down capability, enabling the control of multiple sources and the reduction of operating costs.
• Thermal energy recovery of 95% or higher, allowing self-sustaining at levels as low as 3% while reducing operating costs.
• Customized thermal energy recovery media, providing low-pressure drop and low electrical cost.
Anguil's vast experience, gained after supplying over 1500 successful systems around the world, provided the confidence necessary for Robbie's management to choose Anguil as their continued VOC control supplier. Anguil was able to modify their standard RTO design so as to fit into the space Robbie provided and to execute tear-out and new installation within the agreed-upon six days. The result was a system that exceeded the 98% destruction efficiency objective while lowering Robbie's operating costs by over 60%.
Jeff Kudronowicz is a Senior Application Engineer at Anguil Environmental Systems, Inc. Lori Ashford is the Continuous Improvement Strategist for Robbie Manufacturing, Inc. For more information, contact Jeff at (414) 365-6400 or Lori at (913) 492-3400. Information can also be found on the web at www.anguil.com and www.robbiemfg.com .