Heat transfer and fouling characteristics during falling film evaporation in a vertical sintered tube

Zhao, Limin; Tang, Weiyu; Wang, Lei; Li, Wei; Minkowycz, W. J.

doi:10.1016/j.icheatmasstransfer.2019.104388

Cited by 17 publications

(2 citation statements)

References 34 publications

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“…Similarly to corrosion, an existing organic layer can also act as a crystallization fouling accelerator, as shown in [49]. Porous surfaces were also investigated under fouling conditions [50,51], and it was concluded that they should not be used in applications where intense fouling is expected due to severe deposit build-up. ficient and n the order of reaction.…”

Section: Surface Conditionmentioning

confidence: 99%

A Review of Crystallization Fouling in Heat Exchangers

et al. 2021

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A vast majority of heat exchangers suffer from unwanted deposition of material on the surface, which severely inhibits their performance and thus marks one of the biggest challenges in heat transfer. Despite numerous scientific investigations, prediction and prevention of fouling remain unresolved issues in process engineering and are responsible for large economic losses and environmental damage. This review article focuses specifically on crystallization fouling, providing a comprehensive overview of the state-of-the-art of fouling in heat exchangers. The fundamentals of the topic are discussed, as the term fouling resistance is introduced along with distinct fouling behaviour, observed in laboratory and industrial environments. Insight into subsequent phases of the fouling process is provided, along with the accompanying microscale events. Furthermore, the effects of fluid composition, temperature, flow velocity, surface condition, nucleate boiling and composite fouling are comprehensively discussed. Fouling modelling is systematically reviewed, from the early work of Kern and Seaton to recently used artificial neural networks and computational fluid dynamics. Finally, the most common fouling mitigation approaches are presented, including design considerations and various on-line strategies, as well as off-line cleaning. According to our review, several topics require further study, such as the initial stage of crystal formation, the effects of ageing, the interplay of two or more fouling mechanisms and the underlying phenomena of several mitigation strategies.

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Section: Surface Conditionmentioning

confidence: 99%

A Review of Crystallization Fouling in Heat Exchangers

et al. 2021

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“…Among the more mature evaporation technologies, Multiple Effect Distillation (MED) and Mechanical Vapor Recompression (MVR) were processing technologies with falling film evaporator as the core, and their excellent evaporation characteristics made them occupy an indispensable position in the field of desalination (Kouhikamali et al 2014). However, high-salt wastewater may have caused equipment scaling in the evaporation process, which not only affected the heat transfer performance of the equipment but also caused waste of resources (Zhao et al 2019;Lu et al 2020). Thus, it was necessary to study the problem of equipment salt scaling in coal chemical high salt wastewater salt extraction technology to achieve more efficient recycling of inorganic salts.…”

Section: Introductionmentioning

confidence: 99%

Scaling trend of coal chemical saline wastewater in falling film evaporator: experimental solid–liquid equilibrium and numerical simulation

Liu

et al. 2022

Water Supply

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It was important to master firstly scaling mechanism to slow down scaling, which was one of the important problems faced by saline wastewater treatment with falling film evaporators. In this paper, the phase equilibrium data of ternary system NaCl-CaCl2-H2O at 303.15–373.15 K were measured, and the prediction of the flow characteristics and scaling tendency of salt-containing wastewater in the evaporation tube was investigated by numerical simulation based on the phase equilibrium results. The results showed that the mesostable phase diagram of the ternary system was of simple type, and w(NaCl) and w(CaCl2) showed regular variation with temperature when w(NaCl) in the system was 15–28%. Moreover, the components of the four saline wastewaters (10% NaCl + 9, 10, 11, 12% CaCl2) with less salt content had a faster heating and a faster rate of evaporation of the liquid film in the evaporation tube. Based on the solubility in the experiments and simulations, it was concluded that NaCl crystals were precipitated at tube lengths of 718 mm, 942 mm, 966 mm, and 1,000 mm for four salt concentrations in the evaporation process by comparison, and the reliability of the predicted loci was also demonstrated by a falling film evaporation experimental setup.

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