To meet this need, Tri-Mer Corp. has successfully adapted the design of its continuous-duty NOx scrubber to emergency service. GE’s plant is believed to be the first of its kind for such service.
The Tri-Mer system used at Mt. Vernon comprises two horizontal scrubbing stages, with each stage having its own circulation system. A proprietary combination of caustic, sodium hypochorite 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 is designed to maximize contact between the gas and the scrubbing liquid, while minimizing clogging and fouling.
The scrubber and fan portions of the NOx system operate continuously. On each of the floors of the multistory plant, up to 10 monitors are positioned and programmed to generate audible and visual alarms when NO2 concentration reaches a certain point.
The overall system is completely 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 has also been installed to operate the system in the event of a power failure.
In more traditional, continuous-process applications, the Tri-Mer NOx scrubbers have been designed to 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.