Seawater desulphurization scrubbing in spray and packed columns for a 4.35 MW marine diesel engine

Flue Gas Desulphurization (FGD) is a key topic for all combustion fossil fuel plants and industrial applications. Wet processes are usually preferred when the removal efficiency required to comply with environmental regulation exceeds 90%. Recently, seawater (SW) has been considered as a viable absorbent for FGD processes in coastal and naval applications, thanks to its natural alkalinity and, of course, its large availability. Due to the typical constraints of naval applications, process design should be optimized to improve mass transfer rates and reduce seawater requirements while keeping a suitable absorber size. In this work, we report the experimental findings on process design and optimization of two different SW-FGD units: a spray column equipped with full hydraulic spray nozzles and a packed-bed column with structured packing. The experiments are used to develop and tune suitable models for the packed and spray towers design in representative operating conditions. These models are applied to compare both the units in a reference case study: an IFO fuelled marine diesel engine (4.35 MW) that has to comply with current IMO-MARPOL VI 14 regulation for SECAs. A preliminary costs analysis is also performed for comparison.