Experimental investigation of dynamic characteristics of leaching tubing for solution mining of salt cavern carbon and energy storage

Salt caverns are extensively utilized for storing various substances such as fossil energy,hydrogen,compressed air,nuclear waste,and industrial solid waste.In China,when the salt cavern is leached through single-well water solution mining with oil as a cushion,engineering challenges arise with the leaching tubing,leading to issues like damage and instability.These problems significantly hinder the progress of cavern construction and the control of cavern shape.The primary cause of this is the flowinduced vibration instability of leaching tubing within a confined space,which results in severe bending or damage to the tubing.This study presents a model experimental investigation on the dynamic characteristics of leaching tubing using a self-developed liquid-solid coupling physical model experiment apparatus.The experiment utilizes a silicone-rubber pipe(SRP)and a polycarbonate pipe(PCP)to examine the effects of various factors on the dynamic stability of cantilevered pipes conveying fluid.These factors include external space constraint,flexural rigidity,medium outside the pipe,overhanging length,and end conditions.The experiments reveal four dynamic response phenomena:water hammer,static buckling,chaotic motion,and flutter instability.The study further demonstrates that the length of the external space constraint has a direct impact on the flutter critical flow velocity of the cantilevered pipe conveying fluid.Additionally,the flutter critical flow velocity is influenced by the end conditions and different external media.

Effect of Salt Solution on Characteristics of Soil Infiltration

[Objective] The aim was to study the effect of salt solution on characteristics of soil infiltration, and to provide references for the further studies on the effect of water quality on soil infiltration characteristics and its mechanism. [Method] With the NaCl, CaCl2 solutions as the main test materials, the effect of different water quality and salt solution concentration on soil infiltration was studied under one-dimensional vertical ponded water infiltration at laboratory. [Result] The solution concentration could affect the infiltration performance. The trends of the infiltration rates, cumulative infiltrations and wetting front migration distances were all 50 mg/L 100 mg/L 10 mg/L. At the same concentration, the effect of NaCl solution on soil infiltration characteristics was more significant than CaCl2 solution： in the same time, cumulative infiltration and wetting front migration distance of NaCl solution were greater than CaCl2 solution; compared with NaCl solution, CaCl2 solution took longer time to infiltrate the same amount of water. The dynamic changes of infiltration rate, wetting front and cumulative infiltration were well fitted to the Philip model. [Conclusion] This study only conducted indoor experiment to the infiltration of salt solutions, involving in low concentration and small range. Although it provided some references for the study on the effect of water quality on soil infiltration characteristics and its mechanism, studies in larger areas and with bigger concentrations are demanding.

Modification of FGD gypsum in hydrothermal mixed salt solution

A novel utilization way of the sludge from wet calcium-based flue gas desulfurization （FGD） processes has been developed in this paper. This study focused on the conversion of the FGD gypsum into α-hemihydrate calcium sulfate by a hydrothermal salt solution method at atmospheric pressure. Experimental study has been carried out in a batch reactor. Qualitative and quantitative analyses were made by DSC/TG thermal analysis, SEM, XRD, metalloscope and chemical analysis. The experimental results showed that the modification of FGD gypsum was controlled by the dissolution and recrystallization mechanisms. With the introduction of FGD gypsum the salt solution was supersaturated, then crystal nucleus of α-hemihydrate calcium sulfate were produced in the solution. With the submicroscopic structure of FGD gypsum crystal changed, the crystal nucleus grew up into α-hemihydrate calcium sulfate crystals. Thus ,the modification of FGD gypsum was fulfilled.

Performance of Concrete Subjected to Severe Multiple Actions of Composite Salts Solution under Wet-Dry Cycles and Flexural Loading in Lab

Several action regimes were employed, namely, those exposed to solutions containing single and/or composite chloride and sulfate salts, and under wet-dry cycles and/or flexural loading. The variations in dynamic modulus of elasticity（Erd values） were monitored, as well as the key factor impacting on the chloride ingress when concrete subjected to multiple action regimes was identified by the method of Grey Relation Analysis（GRA）. The changes in micro-structures and mineral products of interior concrete after different action regimes were investigated by means of X-ray diffraction（XRD）, mercury intrusion technique（MIP）, and scanning electron microscopy（SEM）. The test results showed that the cyclic wet-dry accelerated the deterioration of OPC concrete more than the action of 35% flexural loading based on the results of Erd values and the GEA. The analyses from micro-structures could give certain explanations to the change in Erd values under different action regimes.

A robust predictive tool for estimating CO2 solubility in potassium based amino acid salt solutions

The acid gas absorption in four potassium based amino acid salt solutions was predicted using artificial neural network(ANN). Two hundred fifty-five experimental data points for CO_2 absorption in the four potassium based amino acid salt solutions containing potassium lysinate, potassium prolinate, potassium glycinate, and potassium taurate were used in this modeling. Amine salt solution's type, temperature, equilibrium partial pressure of acid gas, the molar concentration of the solution, molecular weight, and the boiling point were considered as inputs to ANN to prognosticate the capacity of amino acid salt solution to absorb acid gas. Regression analysis was employed to assess the performance of the network. Levenberg–Marquardt back-propagation algorithm was used to train the optimal ANN with 5:12:1 architecture. The model findings indicated that the proposed ANN has the capability to predict precisely the absorption of acid gases in various amino acid salt solutions with Mean Square Error(MSE) value of 0.0011, the Average Absolute Relative Deviation(AARD) percent of 5.54%,and the correlation coefficient(R^2) of 0.9828.

Molten-salt synthesis and composition-dependent luminescent properties of barium tungsto-molybdate-based solid solution phosphors

Pr^（3＋）-activated barium tungsto-molybdate solid solution phosphor Ba（Mo_（1-z）W_z）O_4：Pr^（3＋）is successfully fabricated via a facile molten-salt approach. The as-synthesized microcrystal is of truncated octahedron and exhibits deep-red-emitting upon blue light excitation. Powder x-ray diffraction and Raman spectroscopy techniques are utilized to investigate the formation of solid solution phosphor. The luminescence behaviors depend on the resulting composition of the microcrystals with fixed Pr^（3＋）-doping concentration, while the host lattices remain in a scheelite structure. The forming solid solution via the substitution of [WO_4] for [MoO_4] can significantly enhance its luminescence, which may be due to the fact that Ba（Mo_（1-z）W_z）O_4：Pr^（3＋）owns well-defined facets and uniform morphologies. Owing to its properties of high phase purity,well-defined facets, highly uniform morphologies, exceptional chemical and thermal stabilities, and stronger emission intensity, the resulting solid solution phosphor is expected to find potential applications in phosphor-converted white lightemitting diodes（LEDs）.

MOLECULAR DYNAMICS STUDY OF STRUCTURE IN MOLTEN SALT SOLUTION NaF-CaF_2

The NaF-CaF_2 system has been studied by molecular dynamics simulation.The pair correlation functions between cations and anions and the bond angle distributions of cation and anion triplets have been obtained.The bridging and complexing in the system are discussed based on the pair correlation functions and bond angle distributions.The results simulated show that the F^- ions around a Ca^(2+)ion do not form tetrahedron coordination,so some of small complexing clusters such as CaF_4^(2-)are hardly found.A possible structure of F^- ions around Ca^(2+)ions is that three Ca^(2+)ions constitute an equilateral triangle through three Ca-F-Ca bridges and two F^- ions are located over and under the center of the right triangle,respectively.Meanwhile,on the outside of the triangle,every Ca^(2+)ion has other two F^- ions as its neighbors.

Nonmetal-Metal Transition in Solutions of Metals in Molten Salts

Solutions of metals in molten salts present a rich phenomenology: localisatlon of electrons in disordered ionic media, activated electron transport increasing with metal concentration towards a nonmetal-metal (NM-M) transition, and liquid-liquid phase separation. A brief review of progress in the study of these systems is given in this article, with main focus on the NM-M transition. After recalling the known NM-M behaviour of the component elements in the case of expanded fluid alkali metals and mercury and of solid halogens under pressure, the article focuses on liquid metal-molten salt solutions and traces the different NM-M behaviours of the alkalis in their halides and of metals added to polyvalent metal halides.

Determination of Salt Impurities in MDEA Solution Used in Desulfurization of Highly Sulphurous Natural Gas

The foaming phenomenon of N-methyldiethanolamine(MDEA) solution used in desulfurization process occurs frequently in the natural-gas purification plant. The foaming phenomenon has a strong impact on operation of the process unit. The salt impurities are the main reason for causing the foaming of MDEA solution, so the full analysis of salt impurities is necessary. A method for comprehensive analysis of salt impurities in MDEA solution used in desulfurization process was established. Anions and non-metallic cations of MDEA solution were determined by different conditions of ion chromatograph, respectively. Metallic cations of the solution were detected by atomic absorption spectrophotometer with the N2O-C2H2 flame absorption. The analytical results of salt impurities in the desulfurization solution can provide a theoretical basis for an accurate analysis of the factors affecting the foaming of MDEA to unveil further control measures.

Study of Stability of Saturated Salt Solutions Cells

This paper study stability of saturated salt solutions cells at 25 ℃. These cells were prepared and measured at National Institute for Standard （NIS-Egypt） to study the stability of the saturated salt solutions. The study was carried out using three saturated salt solutions, which are Potassium Acetate 22.5%, Potassium Iodide 68.9% and Potassium Sulphate 97.3% to cover low, medium and high relative humidity. The study was carried out using different shapes and volumes half liter spherical, liter spherical and liter conical per each salt which was prepared. The apparatus which used in measurement system in the first time are the same which used after ten years. The results show that the change of relative humidity value after ten years ranged from 0.1% to 0.7%. This value is suitable within uncertainty ＋ 2%. The period of stability for each run for all cells was found to be more than five hours and this period enough for calibration. The measurements show that the cells are stable for more than ten years with accepted value.

SWELLING EQUILIBRIUM OF NONIONIC POLYACRYLAMIDE HYDROGEL IN AQUEOUS SALT SOLUTIONS

A series of nonionic polyacrylamide hydrogels, using acrylamide as monomer and N,N＇-methylene diacrylamide as crosslinking agent, were prepared by the free radical polymerization in aqueous solution. Swelling equilibria for the gels were carried out in aqueous solutions of NaCl, KCI, CaCl2, Na2HPO4 and K2HPO4 with concentration ranging from 10^-3 to 5mol/kgH2O at 25 ℃. Experimental results revealed that the chlorides and phosphates cause a different behavior at higher salt concentration. The swelling ratio increases with increasing concentration of chlorides salts, while decreases with the increased phosphates salt concentration. The phenomena seem to be related to the different interactions of chloride and hydrogen phosphate ions with the network groups. Furthermore, the effects of different concentration of crosslinking agent and total monomers on gel swelling performance were also investigated.

Numerical Modelling of Dissolving and Driving Exploitation of Potash Salt in the Qarhan Playa——A Coupled Model of Reactive Solute Transport and Chemical Equilibrium in a Multi-component Underground Brine System

Firstly, the macroscopic chemical equilibrium state of a series of chemical reactions between intercrystal brine and its media salt layer （salt deposit） in Qarhan Salt Lake was studied by using the Pitzer theory. The concept of macroscopic solubility product and its relation with accumulated ore dissolving ratio were presented, which are used in the numerical model of dissolving and driving exploitation of potassium salt in Qarhan Salt Lake. And secondly, with a model forming idea of transport model for reacting solutes in the multi-component fresh groundwater system in porous media being a reference, a two-dimensional transport model coupled with a series of chemical reactions in a multi-component brine porous system （salt deposits） was developed by using the Pitzer theory. Meanwhile, the model was applied to model potassium/magnesium transport in Qarhan Salt Lake in order to study the transfer law of solid and liquid phases in the dissolving and driving process and to design the optimal injection/abstraction strategy for dissolving and capturing maximum Potassium/ Magnesium in the mining of salt deposits in Qarhan Salt Lake.

Mechanisms and field test of solution mining by self-resonating cavitating water jets

Rapid solution mining is the key to cavern construction in salt formations. Rapid solution mining technology with self-resonating cavitating water jets is described in this paper. It can generate three main physical effects： helical flow dissolution, self-resonating cavitating jet erosion, and ultrasonic waves. A self-resonating cavitating nozzle was also designed with the principles based on theory of fluid transients and hydro-acoustics. Under ambient pressure, the experimental results show that the impulse amplitude of pressure reaches a peak at a standoff distance of 5-13 times the nozzle outlet diameter and the cutting ability of self-resonating cavitating jets is twice that of conventional jets under the same conditions. Compared with the conventional mining method, the field test indicates that rapid solution mining technology with self-resonating cavitating jets can speed the construction by more than 2 times at the pocket stage of cavern development.

Cyclic metallurgical process for extracting Ⅴ and Cr from vanadium slag: Part Ⅰ. Separation and recovery of Ⅴ from chromium-containing vanadate solution

The separation and recovery of V from chromium-containing vanadate solution were investigated by a cyclic metallurgical process including selective precipitation of vanadium,vanadium leaching and preparation of vanadium pentoxide.By adding Ca(OH)_(2) and ball milling,not only the V in the solution can be selectively precipitated,but also the leaching kinetics of the precipitate is significantly improved.The precipitation efficiency of V is 99.59%by adding Ca(OH)_(2) according to Ca/V molar ratio of 1.75:1 into chromium-containing vanadate solution and ball milling for 60 min at room temperature,while the content of Cr in the precipitate is 0.04%.The leaching rate of V reaches 99.35%by adding NaHCO_(3) into water according to NaHCO_(3)/V molar ratio of 2.74:1 to leach V from the precipitate with L/S ratio of 4:1 mL/g and stirring for 60 min at room temperature.The crystals of NH_(4)VO_(3) are obtained by adjusting the leaching solution pH to be 8.0 with CO2 and then adding NH_(4)HCO_(3) according to NH_(4)HCO_(3)/NaVO_(3) molar ratio of 1:1 and stirring for 8 h at room temperature.After filtration,the crystallized solution containing ammonia is reused to leach the precipitate of calcium vanadates,and the leaching efficiency of V is>99%after stirring for 1 h at room temperature.Finally,the product of V_(2)O_(5) with purity of 99.6%is obtained by calcining the crystals at 560℃ for 2 h.

Cyclic metallurgical process for extracting V and Cr from vanadium slag: Part Ⅱ. Separation and recovery of Cr from vanadium precipitated solution

Cyclic metallurgical process for separation and recovery of Cr from vanadium precipitated solution by precipitation with PbCO_(3)and leaching with Na_(2)CO_(3)was investigated.The concentration of Cr residue in the solution decreases from 2.360 to 0.001 g/L by adding PbCO_(3)into vanadium precipitated solution according to Pb/Cr molar ratio of 2.5,adjusting the pH to 3.0 and stirring for 180 min at 30℃.Then,the precipitates were leached with hot Na_(2)CO_(3)solution to obtain leaching solution containing Na_(2)CrO_(4)and leaching residue containing PbCO_(3).The leaching efficiency of Cr reaches 96.43%by adding the precipitates into 0.5 mol/L Na_(2)CO_(3)solution with the mass ratio of liquid to solid(L/S)of 10:1 mL/g and stirring for 60 min under pH 9.5 at 70℃.After filtration,leaching residue is reused in Cr precipitation and leaching solution is used to circularly leach the Cr precipitates until Na_(2)CrO_(4)approaches the saturation.Finally,the product of Na_(2)CrO_(4)·4H_(2)O is obtained by evaporation and crystallization of leaching solution.

A novel fixed-combination timolol-netarsudillatanoprost ophthalmic solution for the treatment of glaucoma and ocular hypertension

Currently commercial fixed-concomitant three agents have multiple problems such as multiple dosing administration,poor efficacy and side effects.Once-daily fixed-combination timolol-netarsudil-latanoprost ophthalmic solution(FC-TNL)has the ability to treat glaucoma by lowering the intraocular pressure(IOP)with great efficacy and improving patient compliance.However,the commercialized netarsudil dimesylate precipitated when the p H of the solution was above 5.4,or when maleic acid,the salt of commercial timolol maleate,was mixed with netarsudil dimesylate.Consequently,the homologous salt engineering strategy was used to make netarsudil dimesylate soluble in p H 4.8–5.2 solution by synthesizing timolol mesylate.Next,the morphology of timolol mesylate was observed by scanning electron microscopy,differential scanning calorimetry,thermogravimetric analysis,and powder X-ray diffraction.The prepared FC-TNL showed good stability during refrigeration storage.Additionally,FC-TNL exerted no influence on the intraocular penetration of each active compounds in the pharmacokinetic study.Importantly,oncedaily FC-TNL exerted potent IOP-lowering effect and protective effect on retinal ganglion cells.The FC-TNL was stable,safe and effective,being a promising glaucoma therapeutic.

Microstructure and corrosion mechanism of as-cast Mg-Zn-Mn-Ca in Hank's solution

An Mg-Zn-Mn-Ca alloy with high Zn content was fabricated by vacuum melting. The as-cast microstructure was investigated using XRD, SEM and EDS. It was shown that the alloy was composed of α-Mg, strip-like Ca2Mg6Zn3 and a few Mn- containing phases. Most of the Ca2Mg6Zn3 phase was distributed at grain boundaries while Mn-containing particles were deposited within grains. The as-cast samples were immersed in a Hank＇s balanced salt solution （HBSS） up to 24 h. The corroded surface morphology and cross-section microstructure were analyzed after different time of immersion so as to understand the corrosion behavior of the alloy. During immersion in the HBSS, the alloy corroded homogeneously at the very beginning and then localized corrosion occurred. The secondary phases protruded on the surface due to the dissolution of α-Mg, suggesting micro- galvanic corrosion occurred with secondary phases acting as the cathode and ct-Mg as the anode. Micro-cracks were formed at the interfaces between Ca2Mg6Zn3 and α-Mg, indicating an undermining tendency of the secondary phases.

Anion type-dependent confinement effect on glass transitions of solutions of LiTFSI and LiFSI

We present findings on the effect of nanometer-sized silica-based pores on the glass transition of aqueous solutions of lithium bis(trifluoromethane)sulfonimide(LiTFSI)and lithium difluorosulfimide(LiFSI),respectively.Our experimental results demonstrate a clear dependence of the confinement effect on the anion type,particularly for water-rich solutions,in which the precipitation of crystalized ice under cooling process induces the formation of freeze-concentrated phase confined between pore wall and core ice.As this liquid layer becomes thinner,the freeze-concentrated phase experiences glass transition at increasingly higher temperatures in solutions of LiTFSI.However,differently,for solutions of LiFSI and LiCl,this secondary confinement has a negligible effect on the glass transition of solutions confined wherein.These different behaviors emphasize the obvious difference in the dynamic properties’response of LiTFSI and LiFSI solutions to spatial confinement and particularly to the presence of the hydrophilic pore wall.

Isolation, Expression Characteristics and Chromosomal Locations of Three cDNA Fragments Under Salt Stress in Rice

cDNA libraries were constructed from the leaves of a rice (Oryza sativa L.) salt tolerancevariety Tesan抋i 2 growing in solutions with 150 mmol/L NaCl for 3 h or without salt stress. Three salt-responsive cDNA clones, Ts1, Ts2 and Ts3 were isolated by differential screening. Northern blottinganalysis showed that the transcription levels of Ts1 and Ts2 increased within 3 h salt stress and kept onincreasing within 24 h, while the transcription level of Ts3 reached its peak within 3 h. Sequence analysisindicated that there were no homologies between the three cDNA clones and any known gene. The threecDNA clones were mapped using a doubled haploid (DH) population derived from an indica variety ZYQ8,which was a salt tolerance parent of Tesan抋i 2, with a japonica variety JX17. Ts1, Ts2 and Ts3 werelocated on chromosomes 1, 3 and 7, respectively. It was noted that Ts1, Ts2, and Ts3 were in or near theregions of major or minor salt tolerance quantitative trait loci (QTLs), which were mapped in the same DHpopulation in a parallel study.

Mineralogy,microstructures and geomechanics of rock salt for underground gas storage

Rock salt has excellent properties for its use as underground leak‐proof containers for the storage of renewable energy.Salt solution mining has long been used for salt mining,and can now be employed in the construction of underground salt caverns for the storage of hydrogen gas.This paper presents a wide range of methods to study the mineralogy,geochemistry,microstructure and geomechanical characteristics of rock salt,which are important in the engineering of safe underground storage rock salt caverns.The mineralogical composition of rock salt varies and is linked to its depositional environment and diagenetic alterations.The microstructure in rock salt is related to cataclastic deformation,diffusive mass transfer and intracrystalline plastic deformation,which can then be associated with the macrostructural geomechanical behavior.Compared to other types of rock,rock salt exhibits creep at lower temperatures.This behavior can be divided into three phases based on the changes in strain with time.However,at very low effective confining pressure and high deviatoric stress,rock salt can exhibit dilatant behavior,where brittle deformation could compromise the safety of underground gas storage in rock salt caverns.The proposed review presents the impact of purity,geochemistry and water content of rock salt on its geomechanical behavior,and thus,on the safety of the caverns.