Vapor pressure above concentrated aqueous solution of lithium bromide at subzero temperatures

Ren, Haoshan; Chen, Guangming; Luo, Jielin; Zhang, Shaozhi

doi:10.1016/j.ijrefrig.2016.03.003

Cited by 11 publications

(8 citation statements)

References 9 publications

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“…This vapor pressure is reached near 253 K, the measured temperature of the microjet in the interaction region. Most studies were performed with the better-characterized LiBr solution, which has a viscosity of ∼7 cP and a vapor pressure of ∼0.5 Torr at 253 K. − This 8.0 m (6.8 M, 41 wt %) solution corresponds to an average mole ratio of 3.5 H 2 O per ion and average ion–ion distance of ∼5 Å. Nearly all water molecules should be involved in ion–water bonding, based on four to five tightly bound H 2 O per Li + ion and six to eight H 2 O more loosely bound to Br – . , In particular, the solvent-separated ion pair Br – ···H 2 O···Li + may be prevalent at this high concentration .…”

Section: Introductionmentioning

confidence: 99%

Liquid Microjet Measurements of the Entry of Organic Acids and Bases into Salty Water

2017

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We explore collisions of hydrogen-bonding molecules with salty water using gas–microjet scattering experiments. Two aqueous solutions, 8 molal (m) LiBr/H2O and ∼4 m K2SO3/H2O at 253 K were exposed to seven organic gases representing different functional groups. These gases comprise weak acids (formic and acetic), weak bases (dimethylamine and piperidine), and an alcohol, ether, and ester (ethanol, dimethyl ether, and methyl formate). The scattering experiments are used to monitor the disappearance of each gas into the aqueous solutions over a ∼100 μs observation time. They demonstrate that formic acid and piperidine disappear into both solutions on almost every collision. Dimers of formic and acetic acid are also captured by the solutions on every collision, despite their pre-existing double hydrogen bonds. The methylene ring of piperidine, (CH2)5NH, also does not interfere with uptake. At the opposite extreme, methyl formate and dimethyl ether are so weakly soluble that they evaporate completely within the observation window, precluding the measurement of their entry probability. Ethanol and dimethylamine represent intermediate cases in which dimethylamine interacts more strongly with dissolved Li+ ions than K+ ions. Collectively, the experiments imply that organic acids and bases reach hydrogen-bonding configurations following nearly every collision, enabling them to be captured by surface water molecules.

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Section: Introductionmentioning

confidence: 99%

Liquid Microjet Measurements of the Entry of Organic Acids and Bases into Salty Water

2017

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“…According to previous studies, the air and volatile impurities dissolved in solution would lead to considerable errors in the measurement of the vapor pressure. − Therefore, it is necessary and crucial to degas the solution. A common degassing method is to freeze the solution at extremely low temperature and vacuum it. − In the experiment, aqueous solution was cooled by liquid nitrogen. When the solution was frozen completely, the valves were opened and the vacuum pump was started to remove the released gas.…”

Section: Methodsmentioning

confidence: 99%

Experimental Research on the Vapor Pressures of CaCl₂–H₂O and MgCl₂–H₂O as Working Fluids of Absorption Heat Transformers at High Temperature

et al. 2021

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Aqueous calcium chloride solution (CaCl2–H2O) and magnesium chloride solution (MgCl2–H2O) are regarded as potential working fluids of absorption heat transformers (AHTs) because of their characteristics of low corrosiveness. The vapor pressure of a working fluid is an important property for applications in absorption systems. However, current experimental data are mostly limited to temperature and concentration ranges, which are suitable for dehumidification systems, whose temperature requirement is always lower than 323.15 K. Thus, more accurate data of vapor pressures are anticipated. In this paper, the equilibrium vapor pressures of aqueous CaCl2 and MgCl2 solution were measured with the static method in the temperature range from 323.15 to 373.15 K. The mass fraction of CaCl2 varied from 0.1 to 0.5, and the mass fraction of MgCl2 varied from 0.05 to 0.3. The measured data were correlated with a common-used e–NRTL model, whose average absolute relative deviations (AARD) for CaCl2–H2O and MgCl2–H2O were 2.27 and 1.61%, respectively. The data were then correlated with a modified Antoine equation, and the AARD were reduced to 0.51 and 0.50%, respectively. The thermodynamic performance of CaCl2–H2O and MgCl2–H2O for the AHT were also estimated for a typical cycle. The results demonstrate that compared with the common-used LiBr–H2O, both CaCl2–H2O and MgCl2–H2O deliver lower circulation ratios with a coefficient of performance difference less than 2%, so their application prospects are illustrated.

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“…Several studies pointed out that the air and volatile impurities dissolved in the solution would lead to considerable error in the measurement of vapor pressure. , Therefore, it is necessary and crucial to degas the solution. A common method for degassing is to freeze the solution down to extremely low temperature and vacuum it. , Here the aqueous HCOOK solution was cooled by liquid nitrogen so that the dissolved gas could be significantly reduced. After the solution was frozen completely, the valves were opened and the vacuum pump was started to remove the released gas.…”

Section: Methodsmentioning

confidence: 99%

“…Several studies pointed out that the air and volatile impurities dissolved in the solution would lead to considerable error in the measurement of vapor pressure. 12,13 Therefore, it is necessary and crucial to degas the solution. A common method for degassing is to freeze the solution down to extremely low temperature and vacuum it.…”

Section: Sample Preparationmentioning

confidence: 99%

“…A common method for degassing is to freeze the solution down to extremely low temperature and vacuum it. 12,13 Here the aqueous HCOOK solution was cooled by liquid nitrogen so that the dissolved gas could be significantly reduced. After the solution was frozen completely, the valves were opened and the vacuum pump was started to remove the released gas.…”

Section: Sample Preparationmentioning

confidence: 99%

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Vapor Pressure of Aqueous HCOOK Solution as Working Fluids of an Absorption Heat Transformer at High Temperature

et al. 2020

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Aqueous potassium formate solution is regarded as a potential working fluid of an absorption heat transformer (AHT) because of its noncorrosive and biodegradable characteristics. The vapor pressure of working fluids is an important property for application in an absorption cycle. However, current experimental data are mostly limited to temperature and concentration ranges that are suitable for a dehumidification system. Thus, more accurate data of vapor pressure are anticipated. In this paper, the equilibrium vapor pressures of aqueous HCOOK solution were measured with a static method in the temperature range from 323.15 to 373.15 K. The mass concentration of HCOOK varied from 10 to 70%. The measured data were compared with the estimated values of a referenced chemical engineering property database (Aspen Plus). A relatively large mean absolute relative deviation (MARD) of 13.27% was found. The data were then correlated with a modified Antoine equation, and the MARD was reduced to 0.45%. The thermodynamic performance of aqueous HCOOK solution for AHT was estimated for a typical cycle.

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Vapor pressure above concentrated aqueous solution of lithium bromide at subzero temperatures

Cited by 11 publications

References 9 publications

Liquid Microjet Measurements of the Entry of Organic Acids and Bases into Salty Water

Liquid Microjet Measurements of the Entry of Organic Acids and Bases into Salty Water

Experimental Research on the Vapor Pressures of CaCl₂–H₂O and MgCl₂–H₂O as Working Fluids of Absorption Heat Transformers at High Temperature

Vapor Pressure of Aqueous HCOOK Solution as Working Fluids of an Absorption Heat Transformer at High Temperature

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Vapor pressure above concentrated aqueous solution of lithium bromide at subzero temperatures

Cited by 11 publications

References 9 publications

Liquid Microjet Measurements of the Entry of Organic Acids and Bases into Salty Water

Liquid Microjet Measurements of the Entry of Organic Acids and Bases into Salty Water

Experimental Research on the Vapor Pressures of CaCl2–H2O and MgCl2–H2O as Working Fluids of Absorption Heat Transformers at High Temperature

Vapor Pressure of Aqueous HCOOK Solution as Working Fluids of an Absorption Heat Transformer at High Temperature

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Experimental Research on the Vapor Pressures of CaCl₂–H₂O and MgCl₂–H₂O as Working Fluids of Absorption Heat Transformers at High Temperature