Parametric analysis and design optimization of wet SOx scrubber system in marine industry

Regulations on emission control of sulfur oxides (SOx) contained in exhaust gas (EG) from ships' engines enter into force. In the recent past, emission control regulations have continually been made more stringent. Consequently, there is an urgent need for novel emission abatement technologies for ship operators, to satisfy the regulations. The objective of this study was to investigate a novel design of a wet SOx scrubber prepared for compliance with the new regulations and to identify the key parameters affecting the SOx removal efficiency and design optimization. The model of wet SOx scrubber system was developed and validated using actual experimental results. On the basis of a parametric analysis, a design for an open-loop mode involving the cooling of the EG inlet temperature via an EG inlet/wash water heat exchanger is proposed. Design optimization results showed that the liquid-to-gas (L/G) ratio and EG inlet temperature could be adjusted to reduce the required power of a seawater (SW) pump by 31.72% and 51.17% for an open-loop system operated inside and outside designated emission control areas, respectively. For a closed-loop system, the adjustment of the L/G ratio, circulating wash water's (WW's) temperature, and chemical dosing flow rate reduced the amount of dose input and required power of the SW pump and circulating WW pump by 11%, 66%, and 49%, respectively.