The world’s largest button manufacturer needed a pollution control system that would destroy styrene emissions and odors from a variety of plant processes. The plant was proactively seeking a cost-effective air pollution control solution to preempt future regulatory action. The main concern of the customer was the high operating cost of an emission control system.
After thorough evaluation of several possible technology solutions, the company selected an Anguil abatement device to treat their styrene emissions. Anguil recommended a uniquely efficient solution in an Emissions Concentrator coupled with a Catalytic Oxidizer. A key factor in this decision was the emission concentrator’s ability to lower the volume of air that needed treatment by achieving a 10 to 1 flow rate reduction. Anguil provided the customer with a static pilot test to prove the effectiveness of the concentrator rotor on styrene. The successful results from the static test ensured the customer’s confidence in the new application of the concentrator technology to control styrene emissions.
Three main considerations guided the design of this solution: the need for an emission control system with low operating costs, the control of the high volume, low volatile organic compound (VOC) concentration of the process air stream, and the unique characteristics of styrene.
Many of the processes that emit styrene, such as boat building and FRP production, have high air flows with low VOC and styrene concentrations. Button manufacturing presents a similar problem but on a slightly smaller scale. The plant’s airflows were approximately 15,000 SCFM (24,075 Nm3/hr) with styrene concentrations ranging from 50-200 ppmv. The customer considered a Regenerative Thermal Oxidizer (RTO) and a bio-filtration system as other possible solutions. While effective in destroying styrene, both of these would have been very expensive solutions because higher air flows result in higher costs for treatment technologies. The operating costs of the RTO and the biofilter were much higher than the chosen solution because these systems had to treat the entire 15,000 SCFM (24,075 Nm3/hr) of process air.
An emissions concentrator coupled with a catalytic oxidizer reduced the process air that needed to be treated by a factor of 10. The high volume airstream, approximately 15,000 SCFM (24,075 Nm3/hr) with 50-200 ppmv of VOC, is passed through the emissions concentrator rotor where the VOCs and styrene are adsorbed in the bed, purifying the high volume air. This high volume air is then exhausted to atmosphere. The concentrator rotor rotates continuously, transporting adsorbed VOCs into a desorption section where they are desorbed from the media with a low volume heated airstream. After being desorbed from the wheel, the air volume has been reduced from 15,000 SCFM (24,075 Nm3/hr) to about 1,500 SCFM (2,407.5 Nm3/hr) and the VOC concentration of the air stream is increased to about 500- 2000 ppmv. This low volume, high pollutant-laden air is then processed by the oxidizer. By isolating and treating the lower air volume, Anguil is able to provide a system with far lower operating costs than other emission control systems.
Anguil was able to further reduce the operating cost of the system by utilizing a catalytic oxidizer to destroy the concentrated, contaminated air stream. Anguil’s experience with styrene emissions has demonstrated the easily oxidizable nature of styrene in the presence of catalyst. Catalytic oxidation systems typically achieve greater than 99% destruction of styrene with relatively low temperature requirements. An Anguil Catalytic Recuperative Oxidizer designed for 1,500 SCFM (2,407.5 Nm3/hr) was installed to process the pollutant-laden airstream with minimal auxiliary fuel consumption.
The final design consideration was to address the unique characteristics of the styrene emissions. The customer was concerned with the possibility of styrene polymerization on the rotor and subsequent system failure. Anguil had performed extensive tests to establish that certain zeolite formulations function better than others in the presence of styrene and eliminate the possibility of polymerization. However, Anguil went to the next step in order to relieve the customer’s concerns. Working closely with one of their technology partners, Anguil ran several static (live) pilot tests to prove the effectiveness and reliability of the concentrator/oxidizer technology. This testing process convinced the customer to move ahead with the Anguil solution.
Another benefit to the customer of the concentrator/oxidizer system was low maintenance cost. The zeolite material has an expected life of 10 years under continuous operation. The easy regeneration and durability of zeolite provides considerable savings over the constant maintenance and replacement required of carbon beds. Additional maintenance savings come from the durable design of the emissions concentrator. The absorbent wheel is rotated with a simple motor and belt drive, reliable components that last at least five years and require minimal maintenance.
In order to expedite installation, Anguil assembled the entire system in its manufacturing facility, allowing for customer review and inspection prior to shipment. The system was then re-erected in the field and integrated into the customer’s process. Anguil’s combination of proven experience and technologically advanced air pollution control products have led to another satisfied customer.