One of the world’s largest printed-circuit board makers turned to Anguil Environmental Systems Inc., Milwaukee, for help with its pollution control requirements.

The electronics company was required to install air pollution abatement equipment to control the volatile organic compounds (VOCs) emitted during the soldering and coating process. The three main considerations were:
  • The need for a system with a competitive capital cost and lowest possible operating cost.
  • The ability to engineer a system that did not affect the sensitive production process.
  • The necessity to install a compliant system as quickly as possible.
After studying the PCB production process and associated emissions, as well as the regulatory mandates, Anguil recommended a its Model 200, a 20,000 scfm (32,000 Nm3/hr) regenerative catalytic oxidizer. Catalytic oxidation has been an effective VOC control technology for many years. It was developed to oxidize VOCs at low temperatures and reduce the high operating costs of direct-flame thermal oxidation. Regenerative thermal oxidation has been used frequently in the past decade. It captures the energy released during oxidation, which lowers operating costs as it optimizes fuel efficiency.

In the Anguil two-bed regenerative catalytic oxidizer, the VOC-laden process exhaust is heated as it passes through the first ceramic media bed located in an energy recovery chamber. The process air moves from the chamber into the catalytic combustion chamber, where the VOCs are oxidized, releasing heat energy into a second recovery chamber. A flow-control valve switches the airflow direction so that energy transfer to the ceramic media in both energy recovery beds are fully utilized, which reduces any auxiliary fuel requirement. The system is designed for a heat recovery of more than 95 percent and is self-sustaining, requiring no added auxiliary fuel even with low VOC loadings.

Many factors are involved in designing a system that maintains low operating costs. For the circuit board customer, high auxiliary fuel (natural gas) costs made the regenerative catalytic oxidizer’s low fuel consumption an appealing option. The addition of a catalyst in the oxidizer’s reaction chamber reduces the VOC destruction temperature, which mean less fuel is consumed than with a regenerative thermal oxidation system. Anguil provided operating cost calculations demonstrating that the fuel savings of the regenerative catalytic oxidizer would provide a full recovery of the catalyst cost in less than 12 months of operation.

The next design consideration was to engineer a system that did not affect the PCB production process. PCB manufacturing, like many other electronics industry applications, requires carefully controlled environments. It is essential that a pollution control system does not exert significant back-pressure on the finely balanced production process and adversely affect the final PCB product. To ensure production quality, Anguil designed the regenerative catalytic oxidizer with a flow-control valving arrangement that prevented any back-pressure from altering the exhaust airflow from the manufacturing process.

The final project consideration was to meet the customer’s stringent time frame. From the outset, Anguil worked with the customer to develop a detailed project management schedule. The complete turnkey installation of the regenerative catalytic oxidizer provided single-source responsibility. The rapid integration of the system into the plant's operations meant minimal downtime.

The system is operating and providing VOC destruction efficiency well above required levels.

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