As part of a commitment to reduce airborne emissions – or the risk of such emissions – the Mt. Vernon, IN plant of GE Plastics – now Saudi Arabia Basic Industries Corporation – installed a NOx scrubber.
SABIC is a diversified manufacturing company, active in chemicals and intermediates. In 2014, it was ranked fourth in the world among chemical companies by Fortune Global 500.
Nitric acid is used in the production of certain resins, and emissions ep are tightly controlled. To address potential upset conditions, the company installed an emergency NOx scrubber engineered and manufactured by Tri-Mer Corp. that can treat up to 66,000 ft./min of air containing 9,600 ppm nitric acid vapor and 1,100 ppm of NO2 for 1 hr.
The Tri-Mer system at Mt. Vernon has two horizontal scrubbing stages, each with a dedicated circulation system. A proprietary combination of caustic, sodium hypochlorite and a reducing agent is used. Blowdown from this stream is safe for disposal at conventional wastewater treatment plants, following pH balancing.
The scrubber internals are fabricated from polypropylene, and the stages are packed with polypropylene Tri-Packs, Tri-Mer’s high efficiency packing media. This packing maximizes contact between the gas and the scrubbing liquid, while minimizing clogging and fouling.
NOx and fan portions of the system operate continuously. On each of the floors of the multistory plant, up to 10 monitors are programmed to generate audible and visual alarms when NO2 concentration reaches a set point.
The overall system is automatic and, during an emergency, functions without operator action.
Should a release occur, surge tanks flood the system with an initial chemical charge; recharging continues until no NO2 is detected at the source or scrubber inlet. An emergency diesel generator operates the system in the event of a power failure.
In more traditional, continuous-process applications, the Tri-Mer NOx scrubbers handle nitrogen emissions from ovens, kilns, incinerators, nitration processes and metal finishing. The systems are designed to accommodate varying ratios of NO to NO2, which is valuable in localities where total NOx control is part of the performance specification.