scholarly journals Direct Measurements of the Deliquescence Relative Humidity in Salt Mixtures Including the Contribution from Metastable Phases

ACS Omega ◽  
2021 ◽  
Author(s):  
Inge Rörig-Dalgaard
Keyword(s):  
Relative Humidity ◽  
Metastable Phases ◽  
Direct Measurements ◽  
Salt Mixtures ◽  
Deliquescence Relative Humidity

Experimental Determination of the Deliquescence Relative Humidity and Conductivity of Multicomponent Salt Mixtures

2002 ◽  
Vol 713 ◽  
Author(s):  
Lietai Yang ◽  
Roberto T. Pabalan ◽  
Lauren Browning
Keyword(s):  
Relative Humidity ◽  
Salt Mixture ◽  
Aqueous Corrosion ◽  
Salt Mixtures ◽  
Pure Salt ◽  
Adsorption Of Water ◽  
Deliquescence Relative Humidity ◽  
Salt Deposits ◽  
Hygroscopic Salts

ABSTRACTThe conductivity of hygroscopic salt deposits containing Na+, K+, NO3– and Cl– ions was measured in air as a function of relative humidity at constant temperatures. The deliquescence relative humidity (DRH) of multicomponent salts containing Na+, K+, NO3– and Cl– was also determined experimentally. The results of the conductivity experiments show that the conductivity of initially dry salt deposits start to increase after reaching a relative humidity value that is 15 to 20% lower than the DRH of the salt. When the DRH is reached, the conductivity increases dramatically as the salt dissolves and transforms into a saturated aqueous phase. The increase in conductivity at humidities below the DRH is attributed to the adsorption of water on the surface of the salt particles. Because of the increase in conductivity, the initiation of aqueous corrosion of metals in contact with hygroscopic salts may occur at a relative humidity much lower than the DRH of the salt. Thus, the onset of aqueous corrosion of metallic nuclear waste package and the drip shield may be earlier, the duration may be longer, and the temperature at which it occurs may be higher than assumed based on the DRH of the salt. The results of the DRH experiments show that the DRH of a salt mixture is usually significantly lower than that of any of its component pure salt.

Corrosion Behavior of Carbon Steel and Stainless Steel Materials under Salt Deposits in Simulated Dry Repository Environments

2002 ◽  
Vol 757 ◽  
Author(s):  
Lietai Yang ◽  
Roberto T. Pabalan ◽  
Lauren Browning ◽  
Darrell S. Dunn
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Relative Humidity ◽  
Multielectrode Array ◽  
Chloride Salt ◽  
Uniform Corrosion ◽  
Salt Deposit ◽  
Steel Material ◽  
Deliquescence Relative Humidity

ABSTRACTIn-situ coupled multielectrode array sensors were used to measure the non-uniform corrosion of carbon steel and stainless steel materials under KCl salt deposit in simulated dry repository environments. It was found that the initiation of non-uniform corrosion occurs at a relative humidity that is 14% lower than the deliquescence relative humidity of the chloride salt. It was found also that once significant corrosion had occurred, the non-uniform corrosion process for the carbon steel material under the salt deposit continues at relative humidities as low as 27%.

scholarly journals Influence of detailing the climate model on the calculation of energy consumption

2020 ◽  
Vol 164 ◽  
pp. 02008
Author(s):  
Elena Malyavina ◽  
Olga Malikova ◽  
Luong Van Pham
Keyword(s):  
Energy Consumption ◽  
Relative Humidity ◽  
Air Temperature ◽  
Climate Model ◽  
Cooling System ◽  
Climatic Data ◽  
Outdoor Air ◽  
Direct Measurements ◽  
Air Conditioning Systems ◽  
Parameter Values

The repeatability of outdoor air temperature and enthalpy combinations in a construction area is a necessary initial information for calculating the energy consumption of air conditioning systems. The most convenient form of presenting climatic data in such calculations is the probabilistic-statistical model, which constitutes a Table, the cells of which show the probabilistic repeatability of the outdoor air temperature and relative humidity. The parameter values given on the vertical and horizontal scales, that form the cell boundaries, can be taken with larger or smaller increments. The paper that served as the basis for this article, provides verification of the initial climatic model detailing experimentally under full-scale conditions in the city of Hanoi (Vietnam). The criterion for the appropriate model detailing was the deviation of the energy consumption estimates of the room cooling system, got experimentally and by calculation. Moreover, the calculations were performed not only on two climate probabilistic and statistical models, but also on the data of direct measurements of the outdoor air temperature and relative humidity with an accuracy of 0.1 for temperature and up to 2 % for relative humidity.

scholarly journals Direct measurements of the RHeq in salt mixtures including the contribution from metastable phases

2021 ◽  
Author(s):  
I Rorig-Dalgaard
Keyword(s):  
Phase Transition ◽  
Relative Humidity ◽  
Phase Changes ◽  
Dynamic Vapor Sorption ◽  
Preventive Conservation ◽  
Salt Mixtures ◽  
Nonequilibrium Conditions ◽  
Equilibrium Relative Humidity ◽  
User Friendly

Abstract Accelerated salt-induced deterioration occurs by frequent changes across the equilibrium relative humidity (RH eq ). Therefore, knowledge of the actual RH eq of a salt mixture has a major impact on preventive conservation to ensure that the relative humidity (RH) does not cause a salt phase transition and in situ desalination as the dissolution of salt is the essential criterion to enable transport of salt (ions) in materials. For decades, it has been possible to determine the RH eq in salt mixtures with the user-friendly, thermodynamic-based ECOS-Runsalt software. However, the ECOS-Runsalt model is challenged by the influence of kinetics along with some limitations in regard to possible ion types and combinations. A dynamic vapor sorption (DVS) instrument is used for the direct measurement of RH eq and to deduce knowledge on the physicochemical nonequilibrium process related to the phase changes in salt mixtures. The experimentally measured RH eq values in this study of NaCl-Na 2 SO 4 -NaNO3, NaNO 3 -Na 2 SO 4 , NaCl-NaNO 3 , NaCl-Na 2 SO 4 , and (NH 4 ) 2 SO 4 -Na 2 SO 4 are in agreement with values from the literature. A comparison with thermodynamically calculated results makes it probable that the phase transition for some salts is significantly influenced by nonequilibrium conditions. The present work bridges some of the existing gaps in regard to accuracy, including the effects of kinetics and the possible ions and combinations that may be found in situ. The proposed method makes it possible to determine a more representative RH eq in relation to real conditions for the improved treatment of salt-infected constructs.

scholarly journals Hygroscopicity of Fresh and Aged Salt Mixtures from Saline Lakes

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1203
Author(s):  
Jun Li ◽  
Wanyu Liu ◽  
Linjie Li ◽  
Wenjun Gu ◽  
Xiying Zhang ◽  
...  
Keyword(s):  
Saline Lakes ◽  
Saline Lake ◽  
Aerosol Particles ◽  
Global Scale ◽  
Positive Matrix ◽  
Ionic Concentrations ◽  
Hygroscopic Properties ◽  
Salt Mixtures ◽  
Dynamic Source ◽  
Deliquescence Relative Humidity

The high hygroscopicity of salt aerosol particles makes the particles active in aerosol and cloud formations. Inland saline lakes are an important and dynamic source of salt aerosol. The salt particles can be mixed with mineral dust and transported over long distances. During transportation, these particles participate in atmospheric heterogeneous chemistry and further impact the climate and air quality on a global scale. Despite their importance and potential, relatively little research has been done on saline lake salt mixtures from atmospheric perspectives. In this study, we use experimental and model methods to evaluate the hygroscopic properties of saline lake brines, fresh salt aerosol particles, and aged salt aerosol particles. Both original samples and literature data are investigated. The original brine samples are collected from six salt lakes in Shanxi and Qinghai provinces in China. The ionic compositions of the brines are determined and the hygroscopicity measurements are performed on crystallized brines. The experimental results agree well with theoretical deliquescence relative humidity (DRH) values estimated by a thermodynamic model. The correlations between DRHs of different salt components and the correlations between DRHs and ionic concentrations are presented and discussed. Positive matrix factorization (PMF) analysis is performed on the ionic concentrations data and the hygroscopicity results, and the solutions are interpreted and discussed. The fresh and aged salt aerosol particles are analyzed in the same way as the brines, and the comparison shows that the aged salt aerosol particles completely alter their hygroscopic property, i.e., transferring from MgCl2− governed to NH4NO3− governed.

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