Numerical Model of SO<sub>2</sub> Scrubbing with Seawater Applied to Marine Engines

Galdo, María Isabel Lamas; Rodríguez, Cristian; Rodrı́guez, Jenny; Telmo, J.

doi:10.1515/pomr-2016-0019

Cited by 23 publications

(17 citation statements)

References 13 publications

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“…With increasing the seawater alkalinity to not only improve the desulfurization efficiency but also weaken effects of SO 2 concentration and liquid–gas ratio, the explanation relies on the fact that a higher‐alkalinity seawater agent can provide a higher alkaline ion concentration to aid the SO 2 ‐absorption reactions consisting of SO 2 (aq) + H 2 O↔H + +HSO 3 − and H + +HCO 3 − ↔CO 2 (aq) + H 2 O . As the overall reaction rate accelerates, the SO 2 partial pressure in the liquid phase decreases, whereas that in the gas phase is maintained, resulting in the mass transfer driving force (i.e., the gap between the two partial pressures) increasing . In consequence, the desulfurization efficiency difference related to the liquid–gas ratio and SO 2 concentration is thus weakened.…”

Section: Resultsmentioning

confidence: 99%

“…According to the absorbent used, wet scrubbers can be divided into open‐loop, closed‐loop, and hybrid systems. The open‐loop system utilizes the seawater's alkalinity to scrub SO 2 and emits the effluent into the sea after use . In this aspect, Han et al experimentally investigated the seawater desulfurization performance under laboratory conditions with a diesel engine exhaust used to represent ship exhaust and found that major seawater parameters such as the flow rate, alkalinity, and temperature significantly affected desulfurization .…”

Section: Introductionmentioning

confidence: 99%

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Seawater/alkaline liquid cascade‐scrubbing desulfurization performance for the exhaust gas of a 162‐kW marine diesel engine

Kuang

Yang

et al. 2019

Asia-Pacific J Chem Eng

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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.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Seawater/alkaline liquid cascade‐scrubbing desulfurization performance for the exhaust gas of a 162‐kW marine diesel engine

Kuang

Yang

et al. 2019

Asia-Pacific J Chem Eng

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“…Previously, researchers had tackled problems pertinent to the spray scrubber applications, both on the experimental and modelling sides. The topic of sulfur dioxide absorption in liquid droplets has been investigated for some years now, from the atmospherical point of view and the simplified chemical models in the beginning [6], to the numerical modelling in the recent years [7]. Maurer [8] investigated the solubility, and the equilibrium concentrations of sulfur dioxide in water, Walcek and Pruppacher [6] studied the atmospherical absorption of SO 2 by clouds and raindrops, while Walcek et al [9] performed experiments on the freely falling droplets in rain shaft.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of sulfur dioxide absorption in water droplets

et al. 2020

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AbstractMass transfer between the phases is a cornerstone of many technological processes and presents a topic whose understanding and modelling is of high importance. For instance, absorption of gases in liquid droplets is an underlying phenomenon for the desulfurization of flue gases in wet scrubbers. Wet scrubbing is an efficient cleaning method where the liquid is sprayed in a stream of rising gases, removing pollutants due to the concentration difference between the gas phase and droplets. A model for absorption in water droplets has been developed to describe the complex physical and chemical interactions during the exposure to flue gases. The main factors affecting the absorption are the mass transfer of pollutants through the gas–droplet interface and the aqueous phase chemistry in a droplet. The mass transfer coefficient, which has been modeled with several approaches, is the most significant parameter regulating the absorption dynamic into the droplet, while the in-droplet chemistry controls the maximum quantity of dissolved pollutants. Dissociation of sulfur dioxide and the chemical reactions in seawater have been described by the equilibrium reactions. Afterward, the influence of the mass transfer coefficient has been investigated, and the model has been validated against the literature data on a single droplet scale. Obtained results are comparable with the experimental measurements and indicate the applicability of the model for the design and development of industrial scrubbers.

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“…Wet scrubbers are divided into open‐loop, closed‐loop, and hybrid systems according to the used agent . The open‐loop system utilizes seawater to remove SO 2 and discharges the sulfur‐adsorbed waste liquid into sea after scrubbing . It has a low operation cost in the agent consumption (using the natural cheap seawater) but necessitates a larger scrubber space, because of a large seawater flux needed for scrubbing and simultaneously neutralizing the discharged liquid.…”

Section: Introductionmentioning

confidence: 99%

Desulfurization performance comparison of a 162‐kW marine diesel engine's exhaust gas based on two kinds of alkaline liquid scrubbing models

Kuang

Yang

et al. 2019

Asia-Pacific J Chem Eng

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A cascade-scrubbing technology was proposed to improve the current oncethrough desulfurization solutions. Desulfurization experiments were performed for a 162-kW marine diesel engine's exhaust gas so as to confirm the alkali-lean/alkali-rich lye cascade-scrubbing advantages compared with the closed-loop solution. In the closed-loop scrubbing model, desulfurization efficiency presented multiple change patterns, such as initially decreasing but then increasing with the liquid-gas ratio, decreasing with SO 2 concentration, and increasing with Na/S. At the high SO 2 concentration of 2,860 mg/Nm 3 and Na/S = 2, desulfurization complying with emission control area's (ECA's) requirements necessitated a liquid-gas ratio above 4.5 L/Nm 3 . Although raising Na/S could decrease the liquid-gas ratio requirement, the alkali-utilization efficiency dropped. In the alkali-lean/alkali-rich lye cascade-scrubbing model under the same SO 2 and Na/S conditions, the auxiliary scrubbing section allowed a desulfurization capacity of 500-750 mg/Nm 3 with an alkali-rich liquid-gas ratio of 1-2 L/Nm 3 . With the alkali-rich lye fed at liquid-gas ratios of 1, 1.5, and 2 L/Nm 3 , the main scrubbing section's alkali-lean lye necessitated liquid-gas ratios of 2.8, 2.4, and 3.1 L/Nm 3 to comply with ECA's requirements, respectively. Two setups approaching the former two liquid-gas ratio assembles (i.e., a total liquid-gas ratio of 4 L/Nm 3 gaining a high alkali-utilization efficiency above 98%) thus confirmed that this cascade-scrubbing model was superior to the closed-loop solution in cutting the liquid-gas ratio requirement and alkali consumption, because of the latter necessitating a liquidgas ratio of 4.5 L/Nm 3 at Na/S = 2 or 4 L/Nm 3 at Na/S = 2.16 but with the alkali-utilization efficiency dropping below 91%.

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Numerical Model of SO₂ Scrubbing with Seawater Applied to Marine Engines

Abstract: The present paper proposes a CFD model to study sulphur dioxide (SO 2

Cited by 23 publications

References 13 publications

Seawater/alkaline liquid cascade‐scrubbing desulfurization performance for the exhaust gas of a 162‐kW marine diesel engine

Seawater/alkaline liquid cascade‐scrubbing desulfurization performance for the exhaust gas of a 162‐kW marine diesel engine

Numerical analysis of sulfur dioxide absorption in water droplets

Desulfurization performance comparison of a 162‐kW marine diesel engine's exhaust gas based on two kinds of alkaline liquid scrubbing models

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Numerical Model of SO2 Scrubbing with Seawater Applied to Marine Engines

Abstract: The present paper proposes a CFD model to study sulphur dioxide (SO 2

Cited by 23 publications

References 13 publications

Seawater/alkaline liquid cascade‐scrubbing desulfurization performance for the exhaust gas of a 162‐kW marine diesel engine

Seawater/alkaline liquid cascade‐scrubbing desulfurization performance for the exhaust gas of a 162‐kW marine diesel engine

Numerical analysis of sulfur dioxide absorption in water droplets

Desulfurization performance comparison of a 162‐kW marine diesel engine's exhaust gas based on two kinds of alkaline liquid scrubbing models

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Numerical Model of SO₂ Scrubbing with Seawater Applied to Marine Engines