Case Study: RTO: Efficient and Reliable Styrene Control Technology

Industry

Composites / Fiberglass

Problem

A producer and supplier of corrosion resistant piping systems was struggling to get the necessary performance out of an unreliable air pollution control system at their facility in Texas. During the manufacturing process, the centrifugally cast mortar pipe systems are reinforced with a fiberglass polymer. This makes the pipe ideally suited for most corrosive piping applications but also produces a significant amount of styrene emissions during production. The plant had been using a 40,000SCFM fixed-bed concentrator and catalytic oxidizer to treat the VOCs (Volatile Organic Compounds) but its poor performance put them in danger of exceeding emission regulations.

Action

With the Texas Commission on Environmental Quality (TCEQ) closely monitoring the facility, the pipe manufacturer quickly identified what qualifications they were looking for in a solution provider:
· Styrene Experience
· Proven Performance
· Stable Supplier
· Cost-Effective Equipment
· Turnkey Capabilities
The RTO (Regenerative Thermal Oxidizer) was selected as the best available control technology and Anguil was quickly determined to be the most qualified supplier.

Solution

As always, Anguil's engineering staff worked closely with the customer throughout the design and manufacturing processes to ensure that the system precisely met their requirements. An Anguil Model 500 RTO (50,000SCFM) was selected based on the process airflow concentrations (450ppmv), destruction rate requirements (98%) and for its overall energy-efficient operation.

Special considerations were taken to deal with the particulate in the process stream. A 48-cartridge collector was put upstream of the oxidizer to collect fiberglass pieces that could clog the RTO. Once filtered, process gases with VOC contaminants enter the oxidizer through an inlet manifold. Dual disk poppet valves direct this gas into energy recovery chambers where the process gas is preheated, then progressively heated in the ceramic beds as they move toward the combustion chamber.

The VOCs are oxidized in the combustion chamber, releasing thermal energy in the structured ceramic media beds that are in the outlet flow direction from the combustion chamber. These outlet beds are heated and the gas is cooled so that the outlet gas temperature is only slightly higher than the process inlet temperature. Fasting acting, vertical poppet valves alternate the airflow direction into the ceramic beds to maximize energy recovery within the oxidizer. The VOC oxidation and high energy recovery within the oxidizer reduces the auxiliary fuel demands and operating costs. For example, at 95% thermal energy recovery, the outlet temperature may be only 70`F (40`C) higher than the inlet process gas temperature with an RTO. The oxidizer can reach self-sustaining operation with no auxiliary fuel usage at low concentrations.

Allen Bradley, Programmable Logic Controllers (PLCs) control the automatic operation of the oxidizer from startup to shutdown, so minimal operator interface is required. These controls also provide for remote telemetry to enable the system’s operation to be viewed and altered via a modem connection to reduce maintenance costs.

The customer is easily satisfying the TCEQ’s 98% destruction rate efficiency requirement and the oxidizer is operating extremely efficient at 95% thermal rate efficiency. Low operating costs and equipment reliability have resulted in another satisfied Anguil customer.