How fundamental knowledge on mass transfer in bubbly flows will help process intensification

Baltussen, M.W.

doi:10.1016/j.cep.2023.109344

Cited by 4 publications

(2 citation statements)

References 16 publications

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“…At the liquid-gas interface, local vortex flows predominantly determine the effective mixing of transported components to the bulk of the liquid, and hence the driving force of gas dissolution. Thus naturally, when system complexity increases due the presence of turbulent flows and corresponding growing variety of bubble structure, it becomes even more difficult to determine the corresponded values and characteristics [41], e.g. formation and deformation of vortices in the liquid phase due to non-uniform buoyancy caused by the local distribution of bubbles, as well as bubble accumulation in the vortex cores and turbulence formation due to bubble migration enhanced flow instability and turbulence.…”

Section: Bubbles As Particles In Non-equilibrium Media Structurementioning

confidence: 99%

Influence of the gas–liquid non-equilibrium media structure on the mass transfer dynamics in biophysical processes

Nizovtseva,

Starodumov,

Lezhnin

et al. 2023

Smart Mater. Struct.

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Multiphase biophysical media are known to be complex structures with continuous high demand to the scientific community for understanding the relationships and ratios between factors affecting the type, dynamics and nature of its structural changes on their impact degree on the media itself. Among the plentiful list of such factors the following do worth mentioning: the lifetime of a particle, turbulence factors and a number of others, each requiring careful analysis, assessment of the contribution degree and, importantly, correct accounting. The present study is focused on such a factor affecting mass transfer intensity change as surface tension through its relationship with the interfacial area: the latter is the site of mass exchange between the gas and liquid phases, and modifications in surface tension values can significantly impact the characteristics of this area, hence altering the rate of mass transfer. By controlling surface tension, one can effectively modulate the size and stability of particles, namely bubbles or droplets, which in turn changes the interfacial area available for mass transfer. The total interfacial area, which is the cumulative surface area of all bubbles, serves as the site for mass transfer. The impact of the surface tension coefficient variation into gas–liquid mass transfer characteristics is analyzed both for the case of water and model liquid. The latter means the potential contribution of surface-active substances was a part of research scope since it was applied to recreate conditions similar to the cultural liquid when microorganisms that produce surfactants are grown. The proposed new methodology assumes calculating interfacial area through the segmentation of images captured by a high-speed camera, thus we can gain a profoundly enhanced understanding of the relationship between surface tension and mass transfer. The precise visual data and subsequent computation of the interfacial area provide deeper insights into the dynamics of bubble formation and the effects of surface tension on bubble size and distribution. As a result, this method has significantly improved our capacity to investigate and optimize mass transfer processes in multiphase biophysical systems. Both analytical approach and results interpretation not only influence affirmatively on deep understanding of natural mechanisms in biophysical media, but also might serve their best for potential application, e.g. in the context of the development of biotechnological industries based on fermentation processes for protein production.

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Section: Bubbles As Particles In Non-equilibrium Media Structurementioning

confidence: 99%

Influence of the gas–liquid non-equilibrium media structure on the mass transfer dynamics in biophysical processes

Nizovtseva,

Starodumov,

Lezhnin

et al. 2023

Smart Mater. Struct.

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“…A small number of plants producing melamine in Europe and around the world and the growing demand for the product have forced constant increases in terms of technological efficiency, e.g., by increasing the reliability and process safety of melamine installations [11][12][13][14]. The full understanding of a process based on a thorough analysis of the areas of potential improvement is a common approach to intensifying industrial processes [15]. On an industrial scale, melamine production is carried out using two independent technologies: high-pressure-noncatalytic and low-pressure-catalytic.…”

Section: Introductionmentioning

confidence: 99%

A Study on Byproducts in the High-Pressure Melamine Production Process

Walczak,

Lemanowicz,

Dziuba

et al. 2023

Materials

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The industrial production of melamine is carried out by the thermal decomposition of urea in two technological processes, using high or low pressure. The reaction may be accompanied by the formation of undesirable byproducts, oxoaminotriazines, and so-called polycondensates, mainly melam, melem, and melon, as well as their hydrates and adducts. Their presence leads to the deterioration of the quality of the final product and may lead to the release of troublesome deposits inside the apparatus of the product’s separation node. With the limited possibility of controlling the crystallization of the byproducts of the process, improving the technological process requires the precise determination of the composition of the separated insoluble reaction byproducts, which is the main objective of this work. This work presents the results of qualitative and quantitative analyses of the composition of deposits sampled in the technological process of melamine production. The full characterization of the deposits was performed using inductively coupled plasma optical emission spectroscopy (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) techniques. The elemental analysis (EA) of carbon, hydrogen, and nitrogen allowed us to obtain characteristic C/H, C/N, and H/N ratios. X-ray diffraction (XRD) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy were also performed to confirm the obtained data. In addition, the morphology of the solid byproducts of the reaction was investigated, and the characteristics of the structures were determined using a scanning electron microscope. The elemental composition was investigated using scanning electron microscopy and the energy-dispersive X-ray spectroscopy (SEM-EDS) technique. The key finding of this research is that about 95% of the deposits are a mixture of melem and melem hydrate. The soluble part of the deposits contains melamine, urea, and oxyaminotriazines, as well as trace inorganic impurities.

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