水力空化强化亚氯酸钠处理船舶柴油机尾气的研究

Research on hydrodynamic cavitation-enhanced NaClO₂ treatment of marine diesel engine exhaust

摘要

针对船舶柴油机尾气湿法治理过程中普遍存在的NO_x脱除效率偏低、气液传质过程受限的技术瓶颈，本文依托“育鲲”轮柴油发电机的实际尾气条件搭建实船实验平台，开展水力空化强化亚氯酸钠(NaClO₂)溶液脱硫脱硝的系统性研究，分别探究淡水溶剂体系下 NaClO₂ 浓度、Cl^-浓度，以及海水溶剂体系下空化反应器进出口压差、溶液温度、初始 pH 对尾气中 NO_x、SO₂ 脱除性能的影响规律。结果表明：水力空化可显著强化低浓度 NaClO₂ 对 NO_x和 SO₂的协同脱除效果；以海水作为溶剂时的脱硝性能显著优于淡水体系；空化反应器前后压差、溶液温度及初始 pH 对脱硝效果的影响均存在适宜区间。本文研究范围内确定的最优运行工况为：浓度 0.3mmol/L 的 NaClO₂ 海水溶液、空化反应器前后压差 500kPa、溶液温度 30℃、初始 pH=6。该技术可有效适配船舶柴油机尾气的实际治理需求，具备良好的工程应用潜力。

Abstract

To address the technical bottlenecks of low NO_x removal efficiency and gas-liquid mass transfer limitation in wet treatment of marine diesel engine exhaust, a non-board experimental platform was established based on the actual exhaust gas conditions of the diesel generator aboard the training ship “Yukun”, and a systematic investigation was conducted on hydrodynamic cavitation-enhanced desulfurization and denitrification by using NaClO₂ solution. The effects of NaClO₂ concentration and Cl^- concentration in the freshwater system, as well as the pressure difference across the cavitation reactor, solution temperature, and initial pH in the seawater system, on the NO_x and SO₂ removal performance from exhaust gas were investigated, respectively. Results show that hydrodynamic cavitation can significantly enhance the simultaneous removal of NO_x and SO₂ in low-concentration NaClO₂ systems. The denitrification performance in seawater is significantly better than that in freshwater. In addition, the effects of the pressure difference across the cavitation reactor, solution temperature, and initial pH on denitrification performance all exhibit optimal ranges. The optimal operating conditions determined within the scope of this study are as follows: NaClO₂ seawater solution at a concentration of 0.3 mmol/L, a pressure difference of 500 kPa across the cavitation reactor, a solution temperature of 30 ℃, and an initial pH of 6. This technology can effectively meet the practical treatment requirements of marine diesel engine exhaust and has good application potential.

关键词

船舶柴油机尾气 / 水力空化 / 亚氯酸钠(NaClO₂) / 脱硫脱硝

Key words

marine diesel engine exhaust gas / hydrodynamic cavitation / sodium chlorite (NaClO₂) / desulfurization and denitrification

参考文献

[1] United Nations Conference on Trade and Development. Review of maritime transport 2025: staying the course in turbulent waters: UNCTAD/RMT/2025[R]. Geneva: United Nations, 2025: 5.

[2] Endresen Ø, Sørgård E, Sundet JK, et al. Emission from international sea transportation and environmental impact[J]. Journal of Geophysical Research: Atmospheres, 2003, 108(D17): 4560.

[3] Sun Ling, Zhang Jingyi, Ducruet C, et al. The impact of shipping activities on air quality and residents’ health in China’s port cities[J]. Journal of Transport Geography, 2025, 123: 104099.

[4] Luo Zhenyu, Lv Zhaofeng, Zhao Junchao, et al. Shipping-related pollution decreased but mortality increased in Chinese port cities[J]. Nature Cities, 2024, 1(4): 295-304.

[5] Bauer M, Czech H, Anders L, et al. Impact of fuel sulfur regulations on carbonaceous particle emission from a marine engine[J]. npj Climate and Atmospheric Science, 2024, 7(1): 288.

[6] Feng Shuo, Li Zhaoming, Shen Bin, et al. A noverview of the deactivation mechanism and modification methods of the SCR catalysts for denitration from marine engine exhaust[J]. Journal of Environmental Management, 2022, 317: 115457.

[7] Van Roy w, Van Roozendael B, Vigin L, et al. International maritime regulation decreases sulfur dioxide but increases nitrogen oxide emissions in the North and Baltic Sea[J]. Communications Earth & Environment, 2023, 4(1): 391.

[8] Maritime Safety Administration of the People's Republic of China. Implementation Scheme of the Global Marine Fuel Oil Sulphur Limit by 2020[Z]. Beijing: Maritime Safety Administration of the People's Republic of China, 2019.

[9] Fedorov K, Dinesh K, Sun Xun, et al. Synergistic effects of hybrid advanced oxidation processes (AOPs) based on hydrodynamic cavitation phenomenon: a review[J]. Chemical Engineering Journal, 2022, 432: 134191.

[10] Gawande G, Mali P, Dhavane P, et al. Hydrodynamic cavitation: a promising technology for water treatment[J]. Materials Today: Proceedings, 2024, 124: 129-139.

[11] 尉世平, 赵兴达, 王沛寒, 等. 水力空化协同纳米铁酸钴催化 PMS 脱硝研究[J]. 大连海事大学学报,2025,51(3):123-130.

[12] wei Shiping, Zhao Xingda, wang Peihan, et al. De-NO_x of PMS catalyzed by hydrodynamic cavitation coordinated with nanocobalt ferrite[J]. Journal of Dalian Maritime University, 2025, 51(3): 123-130. (in Chinese)

[13] 赵毅, 刘凤, 赵音. 亚氯酸钠溶液同时脱硫脱硝的热力学研究[J]. 化学学报,2008,66(15):18-27.

[14] Zhao Yi, Liu Feng, Zhao Yin. Thermodynamic study on simultaneous desulfurization and denitrification by sodium chlorite solution[J]. Acta Chimica Sinica, 2008, 66(15): 18-27. (in Chinese)

[15] Byun Y C, Kim K B. Reaction pathways of NO oxidation by sodium chlorite powder[J]. Environmental Science & Technology, 2009, 43(13): 5054-5059.

[16] Deshwal B R, Jo H D, Lee H K. Reaction kinetics of decomposition of acidic sodium chlorite[J]. The Canadian Journal of Chemical Engineering, 2004, 82(3): 619-623.

[17] Han Zhitao, Yang Shaolong, Zheng Dekang, et al. An investigation on NO removal by wet scrubbing using NaClO₂ seawater solution[J]. SpringerPlus, 2016, 5: 751.

[18] Han Zhitao, Zhao Dongsheng, Zheng Dekang, et al. NO removal from simulated flue gas with a NaClO₂ mist generated using the ultrasonic atomization method[J]. Energies, 2018, 11(5): 1043.

[19] Pourmohammadbagher A, Jamshidi E, Ale-Ebrahim H, et al. Study on simultaneous removal of NO_x and SO₂ with NaClO₂ in a novel swirl wet system[J]. Industrial & Engineering Chemistry Research, 2011, 50(13): 8278-8284.

[20] Flagiello D, Erto A, Lancia A, et al. Advanced flue-gas cleaning by wet oxidative scrubbing (wOS) using NaClO₂ aqueous solutions[J]. Chemical Engineering Journal, 2022, 447: 137585.

[21] Flagiello D, Erto A, Lancia A, et al. Advanced marine scrubbing for simultaneous de-SO_x/NO_x using a wet oxidative process coupled with washwater treatment[C]// The 12th International Conference on Distillation & Absorption, DA 2022. Toulouse: [s.n.], 2022: 1-6.

[22] 王谦. NaClO₂湿法氧化脱硝的研究与工业应用[D]. 上海: 上海交通大学,2017:20-24.

[23] wang Qian. Study and industrial application of wet oxidation denitrification by NaClO₂ [D]. Shanghai: Shanghai Jiao Tong University, 2017: 20-24. (in Chinese)

[24] 冯玮, 王祖武, 王宁, 等. 亚氯酸钠/纯碱溶液处理硝基甲烷工艺废气的脱硝研究[J]. 环境保护科学,2016,42(5):102-106.

[25] Feng wei, wang Zuwu, wang Ning, et al. Study on denitrification of nitromethane process waste gas by sodium chlorite/soda ash solution[J]. Environmental Protection Science, 2016, 42(5): 102-106. (in Chinese)

[26] Yu Xiaoying, Bao Zhanchuan, Barker J R. Free radical reactions involving Cl·, $\mathrm{Cl}_{2}^{-} \cdot$, and $\mathrm{SO}_{4}^{-} \cdot$ in the 248 nm photolysis of aqueous solutions containing $\mathrm{S}_{2} \mathrm{O}_{8}{ }^{2-}$ and Cl^- [J]. The Journal of Physical Chemistry A, 2004, 108(2): 295-308.

[27] 隋昊. 水力空化强化亚氯酸钠海水溶液脱硝的研究[D]. 大连: 大连海事大学,2023:39-42.

[28] Sui Hao. Study on hydrodynamic cavitation enhancement of denitrification by sodium chlorite seawater solution[D]. Dalian: Dalian Maritime University, 2023: 39-42. (in Chinese)

[29] Yamaguchi Y, Iga Y. Thermodynamic effect on cavitation in high temperature water[C]// Proceedings of the ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting. Chicago: ASME, 2014: V002T06A004.

[30] Ge Mingming, Petkovšek M, Zhang Guangjian, et al. Cavitation dynamics and thermodynamic effects at elevated temperatures in a small Venturi channel[J]. International Journal of Heat and Mass Transfer, 2021, 170: 120970.

[31] Zhang Peng, Sun Minglu, Liang Juan, et al. pH-modulated oxidation of organic pollutants for water decontamination: a deep insight into reactivity and oxidation pathway[J]. Journal of Hazardous Materials, 2024, 471: 134393.

[32] Yang Jingxin, Dong Zijun, Jiang Chengchun, et al. Quantitatively assessing the role played by carbonate radicals in bromate formation by ozonation[J]. Journal of Hazardous Materials, 2019, 363: 428-438.

基金资助

国家自然科学基金面上项目(52571401)

国家自然科学基金面上项目(52071046)

中央高校基本科研业务费专项资金资助项目(3132025224)