On Monday night. January 21.1985, the Ciba-Geigy plant in McIntosh, Alabama lost its FRP exhaust scrubber to fire. Earlier that day, the water lines cooling the hot gases had frozen and caused the incinerator system to catch fire.

Ciba-Geigy. extremely concerned with and conscious of the environmental impact of not being able to properly dispose of waste generated at the plant, fully utilized all resources to return the plant to total service in the shortest time possible. An assessment of the repairs required was completed by mid-morning Tuesday, January 22. That same day, Ciba-Geigy selected Rubber Plastics Applicators (RPA) to handle the work. RPA was selected because of Ciba-Geigy's historical dealings with RPA and the company's experience, reputation, and quality of product.

The insurance company estimated it would take twelve weeks to make the repairs. RPA accomplished it in thirteen days by working around the clock to replace the packed tower, stack and all inner conducting ductwork. At Ciba-Geigy's request, RPA used ATLAC 382 polyester resin. The repaired scrubber operates at 170°F-180°F and 30,000 to 40,000 CFM. Exhaust gas from the incinerator is saturated with water and forms an HC1 mist.

The quick reaction by Ciba-Geigy and RPA prevented any harm to the environment. No production time was lost

Since August 1986, two gas scrubbers have been in service as part of an incinerator unit at The Dow Chemical Company's Plaquemine, Louisiana facility. They were fabricated by Rubber & Plastic Applicators, Inc. of Mobile, Alabama, using DERAKANE Vinyl Ester Resins.

According to Dow plant personnel, the first unit measures
50' tall x 6' diameter, while the second is 41' tall x 6' diameter. Both scrubbers were designed for optimum corrosion resistance, because they contact hydrochloric acid and hypochlorites, among other corrosives.

The first scrubber was fabricated using DERAKANE 470-36 Resin, and was hydrotested to 30 psig on the bottom of the vessel. The second consists of DERAKANE 470-45 Resin, and was tested at 25 psig on the bottom of the vessel.

"They have performed up to our design criteria," notes a Dow plant engineer. The scrubbers were filament wound over a standard corrosion barrier, according to Bill Wells, production manager for Rubber & Plastic Applicators. The units were designed for minus 2 to positive 5 psig at 250° F.

Because the inlet temperature can reach 410° F, Dow insulated the bottom 14' of the first scrubber with 1/4" Pyroflex liner and 2" acid brick. The plant has not had any difficulties with the scrubbers, and they do not expect any in the future