Crystallization of urea from an evaporative aqueous solution sessile droplet at sub-boiling temperatures and surfaces with different wettability

Schmid, J.; Zarikos, I.; Terzis, Alexandros; Roth, N.; Weigand, Bernhard

doi:10.1016/j.expthermflusci.2017.10.008

Cited by 46 publications

(23 citation statements)

References 65 publications

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“…Modern technologies widely apply textured surfaces to control wettability and to intensify droplet and film evaporation [4][5][6][7] . The droplet evaporation rate may be effectively controlled by applying surfactants 8,9 .…”

mentioning

confidence: 99%

The crystallization behavior of the aqueous solution of CaCl2 salt in a drop and a layer

Misyura

2020

Sci Rep

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Non-isothermal evaporation during crystallization of CaCl2 salt in a droplet and a thin layer on a hot wall has been investigated experimentally. The growth of salt crystal hydrates (CaCl2·2H2O) on the interface has been studied. It has been found that the change in the initial salt concentration leads to different crystallization rates. The crystallization rate on the droplet interface is many times lower than for a thin layer. The description of crystallization in the salt solution droplet should take into account the crystallization anisotropy, which is associated with the direction of crystallization. The crystallization rate along the contact line of the droplet is many times higher than in the direction of the droplet radius. For a long time of crystallization, the area of the crystal film (outside the drop) increases several times. Four characteristic modes of crystallization to a drop of salt solution have been distinguished. When modeling crystallization, it is necessary to take into account multiple changes in the growth rate of salt crystallohydrates over time, as well as the anisotropic nature of crystallization.

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confidence: 99%

The crystallization behavior of the aqueous solution of CaCl2 salt in a drop and a layer

Misyura

2020

Sci Rep

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“…Evaporation of the water drives the urea concentration up, resulting in a shift in the equilibrium from aqueous solution, to a mixture of solution and solid urea. During evaporation, the solution becomes more and more concentrated, and eventually, re-crystallization is triggered [21]. Different behaviours are observed depending on the nature of the surface a droplet of urea solution is resting on.…”

Section: Résultatsmentioning

confidence: 99%

Understanding humectant behaviour through their water‐holding properties

Crowther¹

2021

Intern J of Cosmetic Sci

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Objective Humectants perform essential roles in the formulation of topical moisturizing products in terms of delivery of active ingredients, consumer experience and biophysical behaviour. How they retain and release water is key to understanding their behaviour. Methods Dynamic vapour sorption (DVS) was used to monitor the dehydration kinetics of three humectants widely used in topical formulations—glycerine, dexpanthenol and urea. Model aqueous solutions with concentrations of 20% w/w were tested and compared against pure deionized water. Results The three humectants varied in their ability to retain water during the dehydration process. Dexpanthenol was able to retain water most efficiently during the latter stages of dehydration. Urea demonstrated evidence of crystallization during the final stage of water loss, which was not shown by glycerine or dexpanthenol. Conclusions Humectants perform vital roles in the formulation of consumer acceptable topical products including the delivery of actives to the skin. Their ability to influence water movement in the skin is also essential for the maintenance of stratum corneum flexibility. DVS assessment of aqueous solutions has demonstrated how the behaviour of three commonly used humectants differs. Knowledge of the mechanisms by which these humectants operate enables the formulator to develop topical products optimized for the roles for which they are intended.

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“…Pembentukan biuret ini harus ditekan karena dapat mengurangi urea yang terbentuk, dan merupakan senyawa yang memiliki sifat racun bagi tanaman [21]. Pembentukan produk samping umumnya disebabkan oleh konsentrasi NCO - [22] dan kondisi operasi yaitu tekanan dan temperatur [23], sehingga penelitian ini bertujuan untuk menekan pembentukan biuret pada produk urea prill dengan mencari temperatur operasi yang optimum. Gambar 2 menunjukkan bahwa temperatur operasi sangat berpengaruh pada peningkatan kadar biuret dalam produk urea prill.…”

Section: Pendahuluanunclassified

Pengaruh Temperatur Operasi Terhadap Penurunan Kadar Biuret Dalam Urea Prill dari Evaporator Tingkat II di PT. Pupuk Kaltim

Septiani¹,

Dhasvianty²,

Ratnawati³

2020

JCPE

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Biuret merupakan hasil samping dalam sintesa pembentukan urea. Kandungan biuret yang tinggi dalam produk urea dapat menjadi racun bagi tanaman sehingga keberadaan biuret harus ditekan. Salah satu faktor terbentuknya biuret adalah temperatur yang tinggi. Penelitian ini bertujuan untuk menentukan temperatur operasi optimum terhadap penurunan kadar biuret dalam urea prill. Analisa dilakukan terhadap enam variabel temperatur operasi 137 o C, 138 o C, 139 o C, 140 o C, 141 o C, dan 142 o C. Sampel dari Evaporator berupa produk urea prill diambil dari belt conveyor, kemudian dilakukan uji kandungan biuret menggunakan spektrofotometer dan kadar air urea prill dengan metode aquatitrator. Hasil penelitian menunjukkan bahwa temperatur operasi optimum pada evaporator adalah 138 o C, karena mampu menghasilkan kadar biuret yang rendah sebesar 0,798% dengan kadar air yang juga rendah sebesar 0,44%, dan tingkat efisiensi penggunaan steam sebesar 211,541 kg/jam.

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Crystallization of urea from an evaporative aqueous solution sessile droplet at sub-boiling temperatures and surfaces with different wettability

Cited by 46 publications

References 65 publications

The crystallization behavior of the aqueous solution of CaCl2 salt in a drop and a layer

The crystallization behavior of the aqueous solution of CaCl2 salt in a drop and a layer

Understanding humectant behaviour through their water‐holding properties

Pengaruh Temperatur Operasi Terhadap Penurunan Kadar Biuret Dalam Urea Prill dari Evaporator Tingkat II di PT. Pupuk Kaltim

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