Author(s)

ROBERT G. RICHARDSON

Abstract

This paper bridges controversy surrounding marine open loop exhaust gas scrubbing restrictions. The solutions offered in this paper apply equally well to both open and closed loop scrubbing methodology. The chlorine dioxide (ClO₂) based gas/mist scrubbing technology presented in this paper works equally well in open and closed loop applications. This ClO₂ based gas/mist phase exhaust scrubbing technology effectively removes more than 99% of SO_X and most of the organic compounds including polycyclic aromatic hydrocarbon compounds (PAH) that create soot in marine exhaust. The very same ClO₂ based gas/mist scrubbing equipment can also be configured to simultaneously treat SO_X and NOX, plus most of the organic compounds that create soot. Where permitted, the sulfur based salts generated from the ClO₂ based gas/mist SO_X abatement process can be discharged directly into the sea without the typical additional washwater treatment required when SO_X is treated with seawater scrubbers. Alternatively, when closed loop scrubbing is required, this ClO₂ based gas/mist scrubbing process can store the sulfur based SO_X reaction products as a very low volume paste until the ship is in a location that allows paste to be discharged into the sea. The scrubbing device is a simple cylinder that fits into the ship’s funnel and a small skid of equipment plus chemical storage that can be configured together or separately in the mechanical area of the ship. Overall, this equipment has a small physical size, high removal efficiency, and low equipment/operating cost. This ClO₂ based gas/mist phase scrubbing technology can be combined with existing abatement equipment or used on its own. The ClO₂ based gas/mist scrubbing technology is in full compliance with IMO regulations for SO_X, NO_X and soot.

Keywords

exhaust, scrubber, open-loop, closed-loop, chlorine dioxide, SO_X, NO_X, soot