Coming Into Compliance

As part of meeting new MACT standards, one fiberglass manufacturer uses thermal oxidizer technology to capture the contaminant styrene and use it as a fuel source

• By Jim Stone
• May 01, 2007

For years, fiberglass-reinforced baths and showers have been perceived as “commodity” products. Of course -- as with any product -- there have always been quality differences between brands. Nevertheless, the manufacturing methods employed and the materials used have been roughly similar.

That’s all changed. As of April 21, 2006, manufacturers of reinforced plastic composites are required to meet hazardous air pollutant emission restrictions under new “maximum achievable control technology” (MACT) standards, published by the U.S. Environmental Protection Agency.

The MACT Impact
The new MACT standards required manufacturers of plastic composites either to install new air pollution control technology or compromise formulations by reducing styrene levels. Styrene is used for two purposes: 1) as an agent for spraying and 2) as a cross-linking agent. This gives the hardness and rigidity to items such as bathtubs.

Styrene, a vital component of the fiberglass-reinforcement technology, is released into the air during the manufacturing process. While health and environmental concerns have not been confirmed (styrene quickly breaks down in the atmosphere), EPA’s precautionary measures now require manufacturers to capture and control 95 percent of styrene emissions.

In order to comply with the new MACT standards, a manufacturer has several options:

1. Ignore regulations and face fines and possible plant closures.
2. Reduce the amount of styrene used in the creation of products, resulting in a weaker product.
3. Use lower-emitting, less-effective resins. This option requires the use of more reinforcing material.
4. Invest in pollution control technologies that will capture and eliminate styrene. This option allows a manufacturer to create products using the most effective and strongest formulation of materials, resulting in the highest quality products.

Manufacturers that do not install sophisticated capture-and-control emissions equipment must reduce the level of styrene they used in the resin formula. The result is a weaker product.

Those manufacturers that solve this problem through capital improvements are able to offer a higher-quality fiberglass-reinforced bathing product.

One Manufacturer’s Strategy
Lasco Bathware has invested more than $20 million to make MACT-compliant capital improvements and renovate its manufacturing plants. This investment provides several distinct competitive advantages:

* Lasco’s investment of more than $2 million in each of its eight U.S. manufacturing plants means the company now exceeds new clean air standards..
* By effectively gathering styrene and burning it in a thermal oxidizer, the manufacturer has reduced styrene emissions by approximately 250,000 tons per year. Using the captured and incinerated styrene as a fuel, Lasco has also reduced its dependence on other energy sources.
* Lasco’s response allows the company to use the optimum formulation of styrene in its fiberglass-reinforcement process, resulting in the greatest possible strength, durability and overall quality of its products.
* Lasco has also begun using state-of-the-art robotic technology in its manufacturing process. The effect is greater product quality and reliability.

For this project, the Environmental & Energy Systems division of Dürr Systems installed a Disc® Concentrator System. The system included a rotary concentrator with a rotary valve regenerative thermal oxidizer (RTO). The rotary concentrator, which features a proprietary material supplied by Dürr’s exclusive supplier, does not allow styrene to polymerize on its surface. Dürr was able to guarantee a five-year life of this material, which was a major selling point. A high-efficiency filter was installed upstream to remove any particulate matter coming into the air stream. By utilizing the concentrator system, the net cost increase was approximately $2 per unit, a significantly lower cost compared to the alternatives considered. Since Lasco produces greater than a million units per year, this represented a significant savings to the company.

According to Syd Pe, project manager at Lasco, the fuel economy provided by the concentrator system proved to be a major factor in the final decision. “Because of the fuel economy, we were able to increase airflow in the plants without increasing fuel consumption,” said Pe. “We wanted a five-year guarantee on the absorbent, and that came with the contract.”

The concentrator system was designed to operate without any natural gas consumption. The concentrator removes the styrene from the air stream, concentrates it over 10 times and then feeds it into the RTO for destruction. This provides enough energy to operate the RTO without adding any external fuel.

Conclusion
Another air pollution control manufacturer proposed a less efficient oxidizer, a recuperative system, but the unit had high fuel consumption. So, in the short term the RTO system was not the absolute lowest cost but over the long term, the RTO system definitely will be more cost-effective. Overall, the cost of ownership of the RTO system, which is more energy-efficient, will be much lower for the fiberglass manufacturer.

This article originally appeared in the 05/01/2007 issue of Environmental Protection.