Kuang, Min, Hu, Xuehui, Yang, Guohua, Wang, Jinxin, Yuan, Guanghui, Tao, Chujiong, Wu, Sili, Ding, Jieyi, and Meng, Xinyi
A cascade‐scrubbing technology was developed for marine diesel engines to improve the current once‐through desulfurization solutions. To confirm the seawater/alkaline liquid cascade‐scrubbing advantages of higher efficiencies and lower lye consumption compared with current solutions, desulfurization experiments with different scrubbing models were performed for a 162‐kW marine diesel engine. In the open‐loop model with SO2 of 1,000–2,860 mg/Nm3, desulfurization with the allowed liquid–gas ratios ≤8 L/Nm3 for the packing tower failed to fully meet the ECA's requirements, despite the efficiency increasing with liquid–gas ratio, seawater alkalinity, and packing height and decreasing with SO2 concentration. In the closed‐loop solution, to obligate the ECA's requirements with SO2 of 2,860 mg/Nm3, a high liquid–gas ratio of 4.8 L/Nm3 was necessitated at Na/S=2. In contrast, in the seawater/alkaline liquid cascade‐scrubbing model under high‐sulfur and low‐alkalinity conditions (2,860 mg/Nm3 and 0.84 mmol/L), the solution utilized 5–6 L/Nm3 seawater in the main scrubbing section to scrub 80–90% SO2 and an extremely low alkaline‐liquid dose below 1 L/Nm3 in the auxiliary scrubbing section to remove the residual SO2, finally allowing a high efficiency ahead of the open‐loop model and meanwhile cutting down an 80–90% lye consumption compared with the closed‐loop model. [ABSTRACT FROM AUTHOR]