The Solubility of Urea in Water. The Heat of Fusion of Urea

The solid-liquid phase boundaries on new innovative solvents for the carbon capture and storage (CCS) technology have been measured in this work. The solvents have been formulated with vapour reduction additives (VRAs) also known as water lean solvents. The solid-liquid equilibrium (SLE) data will create better prediction models for the CCS technology and prevent precipitation in process equipment and thereby reduce the risk of costly shutdowns. The presented SLE data cannot be used in the prediction of solid formation in condenser as it would require knowledge of the vapour-liquid-solid equilibria. 2The SLE of the systems urea-H2O, urea-monoethanolamine (MEA)-H2O, and monoethylene glycol (MEG)-H2O have been determined using the methods freezing point depression (FPD) and SLE by FPD. 61 new SLE data points are listed of 0 < w(urea) < 60 %, and 0 < w(MEG) < 20 %.It is the first time that the ternary systems have been measured. The eutectic temperatures were found at -8 °C for urea-H2O and -27 °C for urea-MEA-H2O. Highly concentrated urea solutions freeze completely upon mixing water with MEA due to the endothermic reaction. Solubility data of MEG-MEA-H2O was found for t > -40 °C. All SLE points for MEG in 30 wt% aqueous MEA freezes below -15 °C.To avoid clogging from urea precipitation, it is recommended to use urea below 30 wt%.

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“…The experimental SLE data obtained in this work is in line with the literature [14][15][16][17][18][19][20][21][22][23][24][25] on urea-H2O.…”

Section: Resultssupporting

confidence: 88%

“…The experimental solubility results of urea in water and urea in mixtures of MEA-H2O are presented in Table 3 and Table 4 together with literature data [14][15][16][17][18][19][20][21][22][23][24][25] on urea-H2O. The SLE temperatures, standard deviations, and information on solid formation are all listed in the tables.…”

Section: Resultsmentioning

confidence: 99%

Solid–Liquid Equilibria of a 30 wt % Aqueous Monoethanolamine Solution Containing Urea and Monoethylene Glycol

et al. 2021

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“…Below this line the urea starts precipitating into the solution. The urea-water phase diagram is presented similarly to Babkina et al [15] and it is based on literature data from [16][17][18][19].…”

Section: Measurement Of Kinematic Viscositymentioning

confidence: 99%

“…Measurement points in the experiment are presented as open circles. The liquidus line of UWS for a fully saturated solution, obtained from the literature, is presented with filled symbols[16][17][18][19] …”

mentioning

confidence: 99%

Urea-Water-Solution Properties: Density, Viscosity, and Surface Tension in an Under-Saturated Solution

Halonen

Kangas

Haataja

et al. 2016

Emiss. Control Sci. Technol.

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A temperature-concentration dependent surface fit for the relative viscosity of a urea-water-solution (UWS) is calculated based on experimental and literature data. For the surface fit, a 2D Lorenzian function was used, where the xaxis was assigned to a urea mass fraction and the y-axis to the solution temperature and the rest of the parameters were optimized based on the experimental and literature data. The surface model describes the relative viscosity of undersaturated urea-water-solution (UWS). The experimental data for the kinematic viscosity was measured with an Ubbelohde capillary viscometer whose temperature was controlled with a thermostat. The temperature and concentration range was from 293.15 to 353.15 K in 10 K increments and for urea mass fractions from 0.325 to 0.7. The kinematic viscosity values from the experiment were converted to relative viscosity by calculating the density of the UWS. An exponential fit was calculated to describe the specific gravity of the UWS based on literature data. Additionally, the surface tension of the UWS was measured at room temperature (293.15 K) in a mass fraction range from 0.302 to 0.596. As a result, simple models describing UWS properties were obtained and these models can be implemented into computational fluid dynamics (CFD) simulations.

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“…Urea is a highly water‐soluble organic compound and its solubility increases from 107.9 g/100 mL at 20°C to 400 g/100 mL at 80°C (http://en.wikipedia.org/wiki/Urea). The present work reports the dispersion of alumina powder in the highly concentrated aqueous urea solutions and their setting for the preparation of alumina ceramics with aligned pores.…”

Section: Introductionmentioning

confidence: 99%

Dispersion and Setting of Powder Suspensions in Concentrated Aqueous Urea Solutions for the Preparation of Porous Alumina Ceramics with Aligned Pores

2013

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Highly concentrated alumina powder suspensions have been prepared in aqueous urea solutions of concentrations in the range 200–360 g/100 mL using an ammonium poly(acrylate) dispersant at 80°C. The dispersant concentration for the suspension viscosity minimum in the urea solutions is higher than that in water due to the higher processing temperature. The urea solutions having higher dielectric constant than that of water offer higher interparticle potential that resulted in better dispersion of the powder as evidenced from the lower viscosity and yield stress of the suspensions. The decrease in temperature increased the suspension viscosity and the suspension formed a strong gel when cooled to room temperature due to the crystallization of urea. The minimum urea solution concentration for a 55 vol% alumina suspension to form a dimensionally stable gel is 240 g/100 mL. The compressive strength and Young's modulus of the gels increased with the increase in urea solution concentration. The alumina ceramics prepared by the urea removal followed by sintering at 1500°C had porosity in the range 28–36 vol% with the rectangular rod‐shaped aligned pores.

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The Solubility of Urea in Water. The Heat of Fusion of Urea

Cited by 28 publications

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Solid–Liquid Equilibria of a 30 wt % Aqueous Monoethanolamine Solution Containing Urea and Monoethylene Glycol

Solid–Liquid Equilibria of a 30 wt % Aqueous Monoethanolamine Solution Containing Urea and Monoethylene Glycol

Urea-Water-Solution Properties: Density, Viscosity, and Surface Tension in an Under-Saturated Solution

Dispersion and Setting of Powder Suspensions in Concentrated Aqueous Urea Solutions for the Preparation of Porous Alumina Ceramics with Aligned Pores

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