Thermal diffusion in branch columns for improved separation

Yeh, Ho‐Ming

doi:10.1016/j.jtice.2013.01.011

Cited by 3 publications

(3 citation statements)

References 16 publications

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“…İki sıvı veya gaz karışımındaki bir sıcaklık farklılığı konsantrasyon farklılığına yol açtığında, termal difüzyon olayı meydana gelir ve bileşenlerden biri bu esnada sıcak duvarda konsantre edilirken, diğer bileşen ise soğuk duvar kenarında konsantre hale gelir. Azeotroplar, izomerler ve izotoplar gibi karışımların alışılageldik metotlarla ayrılması, zor hatta imkansız olup, termal difüzyonla etkili bir şekilde ayrılabilirler[66]. Konsantrasyonların farklı olduğu gaz faz içerisindeki iki bölge, geniş boşluklara sahip olan bir elek ile ayrılırsa, bu işlem atmoliz olarak adlandırılmaktadır.…”

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The Role of Mass Transfer in Membrane Systems

Gürel¹,

Büyükgüngör²

2015

Pamukkale J Eng Sci

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Membranlar, son yıllarda oldukça popüler arıtım sistemleri arasında ön planda yer almaktadır. İçme suyu arıtımı, atıksu arıtımı ve deniz suyundan içme suyu eldesi gibi birçok alanda membranların kullanımı yaygınlaşmıştır. Özellikle membranların atıksuların arıtımı konusunda klasik sistemlere karşı olan üstünlükleri ve gün geçtikçe düşüş gösteren membran materyali maliyetleri, bu sistemlerin tercih edilebilir seçenekler arasına girmesini sağlamıştır. Membranların oldukça farklı türleri bulunmaktadır. Bunlar arasında mikrofiltrasyon (MF), ultrafiltrasyon (UF), nanofiltrasyon (NF) ve ters osmoz (RO) en fazla ilgi çeken proseslerdir. Membran proseslerde en önemli hususlardan biri, membrandan geçen ve membranda tutulan bileşen miktarlarıdır. Burada kütle aktarımı kavramı ortaya çıkmaktadır. Kütle aktarımı, arıtım sistemlerinin projelendirilmesinde ve verimlilik hesaplarının yapılmasında oldukça büyük önem taşıyan bir olaydır. Membranlarda gerçekleşen kütle aktarımının incelenmesi, yukarıda söz edilen konulara ek olarak, farklı membran tiplerinin karşılaştırılması açısından da önem taşımaktadır. Bu derleme makalesi kapsamında, membranlar ile ilgili genel bilgilere, membranların türlerine, kullanım alanlarına ve modül tasarımlarına yer verilmiş, kütle aktarımı kavramı incelenmiş ve membran arıtım sistemlerinde gerçekleşen kütle aktarımı işlemleri değerlendirilmiştir. Membranes are situated in the foreground among the considerably popular treatment systems in the last years. The use of membranes was become widespread in many fields such as drinking water treatment, wastewater treatment and obtaining drinking water from sea water. The predominance of membranes against the classical systems regarding the wastewater treatment, and the decreasing cost of membrane materials each day provided these systems to enter among the preferable options. There are considerably different types of membranes. Microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) are the processes drawing most attention. One of the most important considerations in membrane processes is the amount of constituents passing from the membrane and rejecting by the membrane. Mass transfer concept arises in this place. Mass transfer is a critically important case used in the design of treatment systems and the estimation of efficiency. In addition to the points mentioned above, investigation of mass transfer occurring in membranes is important in comparing of different membrane types. In this review article, general information about the membranes, membrane types, uses of membranes and module designs are given, concept of mass transfer is viewed and the mass transfer processes realizing in these treatment systems are assessed.

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The Role of Mass Transfer in Membrane Systems

Gürel¹,

Büyükgüngör²

2015

Pamukkale J Eng Sci

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“…A termodifusão tem várias aplicações industriais, como na separação de misturas de isótopos, no fracionamento de polímeros (GHORAYEB e FIROOZABADI, 2000;RABINOVICH et al, 1979;RUE e SCHIMPF, 1994;GIDDINGS, 1994), na fabricação de dispositivos semicondutores em metal fundido e misturas semicondutoras e na manipulação de macromoléculas como o DNA (ESLAMIAN, 2011). Misturas, tais como azeótropos, isômeros e isótopos, que são de difícil separação por processos convencionais, podem ser eficientemente separados por difusão térmica (YEH, 2013). Alguns dos principais trabalhos de pesquisa e publicações sobre termodifusão foram produzidos pela indústria do petróleo, devido ao papel da termodifusão na distribuição dos componentes nos reservatórios subterrâneos (difusão térmica em meio poroso) (FAISSAT et al, 1994;COLOMBANI et al, 2002;JABER et al, 2006).…”

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“…Os , 2011;BIRD et al, 2004). Esse processo, também conhecido como separação termogravitacional, explora a diferença de densidades entre a região quente e fria (ENCENARRO et al, 1993;YEH e HSU, 2011;YEH, 2013). A Figura 3 mostra um esquema de duas colunas termogravitacionais onde a mistura a ser separada é mantida dentro de um espaço estreito entre dois tubos verticais concêntricos (Figura 3a) ou entre duas placas planas verticais (Figura 3b) que são submetidos a uma diferença de temperatura (BOU-ALI et al, 1998;PLATTEN, 2006).…”

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Processos de separação empregando tecnologia supercrítica e difusão térmica

Diniz¹

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The aim of this work was to achieve two main objectives. The first one was to study the influence of thermal diffusion (Soret effect) on systems containing dissolved solutes in supercritical fluid. Such study consisted in designing and constructing an equipment in which experimental measures for two systems were made, one consisting of a mixture of sunflower oil refined with oleic acid and another of limonene with linalool. These mixtures were used to represent two model systems, one of vegetable oils (I) deacidification and another of orange (II) essential oil deterpenation, respectively. The second objective was to calculate thermodynamic properties using the Peng-Robinson equation of state (EOS-PR) with the classical mixing rule and to estimate the thermal diffusion factor using Kempers model. To that goal, the binary interaction parameters between the pairs of mixture components were obtained by adjusting the thermodynamic model to experimental data (isothermal) of oleic acid solubility, sunflower oil, limonene and linalool in supercritical carbon dioxide. A computational program was developed to calculate thermodynamic properties based on the equations derived from the EOS-PR, properties that are necessary to calculate the thermal diffusion coefficient by the Kempers model. The results showed that the designed equipment was able, with some limitations, to provide experimental results for the two model systems. The collected data showed that thermal diffusion influenced the separation of the mixture components of the model II system, while for model I system there was no fractionation. In the thermodynamic modeling of the binary systems phase equilibrium using the EOS-PR, a good correlation was obtained for the two model systems. However, for model II system, the results showed that the critical properties have significant influence over the thermodynamic modeling performance, and a correction of these values is necessary. For the non-isothermal system modeling, most of the effort to estimate the Soret effect was put in calculating the thermodynamic mixing properties. The obtained values for the thermal diffusion factor showed a strong dependence on the binary interaction parameters and a sensitivity to errors in the mixture thermodynamic properties. In spite of that, the modeling proposed in this work represents qualitatively the experimental data behavior, being able to clarify in which conditions of pressure, temperature and composition the best separation can be obtained. Therefore, the results were promising and will serve as a basis for future developments, since further research in this area is necessary to extend the application of thermal diffusion in supercritical environment to other mixtures to apply modifications in the experimental system and to implement new models to calculate the thermal diffusion coefficient.

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Appling the computational fluid dynamics studies of the thermogravitational column for N₂-CO₂ and He-Ar gas mixtures separation

Salimi

Hashemipour

Karimi-Sabet

et al. 2021

Chemical Product and Process Modeling

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In the present work, three-Dimensional stationary numerical simulations were accomplished for a deeper understanding of the gas mixtures separation by the thermogravitational column. To address the optimum condition and examine the limitation of the process, the thermogravitational column behavior has been thoroughly analyzed. First, the simulation model was validated by the experimental results of Youssef et al. then the model was developed for the pilot column. The mixture of helium-argon was chosen as feed composition. It was concluded that the variation of the separation factor in relation to pressure for both columns was almost the same. The optimum condition verified as p = 0.2 atm , θ = 0.4 , m ° = 4 SCCM $p=0.2\text{atm},\theta =0.4,m{\degree}=4\,\text{SCCM}$ .

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Thermal diffusion in branch columns for improved separation

Cited by 3 publications

References 16 publications

The Role of Mass Transfer in Membrane Systems

The Role of Mass Transfer in Membrane Systems

Processos de separação empregando tecnologia supercrítica e difusão térmica

Appling the computational fluid dynamics studies of the thermogravitational column for N₂-CO₂ and He-Ar gas mixtures separation

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Thermal diffusion in branch columns for improved separation

Cited by 3 publications

References 16 publications

The Role of Mass Transfer in Membrane Systems

The Role of Mass Transfer in Membrane Systems

Processos de separação empregando tecnologia supercrítica e difusão térmica

Appling the computational fluid dynamics studies of the thermogravitational column for N2-CO2 and He-Ar gas mixtures separation

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Appling the computational fluid dynamics studies of the thermogravitational column for N₂-CO₂ and He-Ar gas mixtures separation