Observed Crystallization Induction Time in Seeded Gypsum Crystallization

Choi, Jin Yong; Lee, Tae; Cheng, Yifan; Cohen, Yoram

doi:10.1021/acs.iecr.9b06050

Cited by 29 publications

(16 citation statements)

References 46 publications

(115 reference statements)

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“…Techniques 2 and 3, with occasional use of technique 4, also have a high probability of success but require field validation and optimization. The mechanistic basis is predicated on the slow process of gypsum nucleation detailed in numerous studies (Choi et al, 2019, Melliti et al, 2021. The long induction time can be exploited by limiting the solution residence time within the FO system.…”

Section: Recommendations For Higher Water Recoveries and Minimal Clea...mentioning

confidence: 99%

Energy Efficient Waste Heat Coupled Forward Osmosis for Effluent Water Management at Coal-Fired Power Plants

Rajagopalan¹

2021

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This project sought to evaluate the technical and economic viability of the Aquapod © , a transformational low energy (<200 kJ/kg water) waste heat coupled forward osmosis (FO) technology, to manage effluents, meet cooling water demands, and achieve water conservation in a coal-fired power plant environment.The Aquapod © process is innovative because it is heat-driven, avoids the evaporation of water, and uses no toxic chemicals such as ammonia or amines. The Aquapod © process accomplishes this using an aqueous two-phase system (ATPS) coupled FO process.The evaluation revealed that the Aquapod © process offers a pathway to exploit waste heat resources within a power plant to achieve flue-gas desulfurization (FGD) wastewater volume reduction and water recovery with minimal pretreatment. Water recovery of 80% from FGD wastewater was achieved with minimal pretreatment, exceeding the project target of 50%. The estimated electrical energy of 2.16 kWh/m 3 of water produced for the Aquapod © process met the project target of < 3.6 kWh/m 3 . The heat required for the process operation was approximately 186 kJ/kg of produced water, which was slightly lower than the project target of 200 kJ/kg.The estimated treatment cost for installing and operating the Aquapod © process in conjunction with a spray dryer evaporator to achieve zero-liquid discharge (ZLD) of the 100 gpm FGD wastewater was $13.24/m 3 over a 30-year lifetime. As a point of reference, this study's host power plant currently incurs a cost of $3.70/m 3 -$8.87/m 3 on a discharged volume basis to discharge its wastewater into the publicly owned treatment works (POTW) after physicalchemical treatment. Therefore, the Illinois power plant would incur an incremental cost increase of $4.37/m 3 -9.54/m 3 to achieve ZLD using the Aquapod © and spray dryer combination.

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Section: Recommendations For Higher Water Recoveries and Minimal Clea...mentioning

confidence: 99%

Energy Efficient Waste Heat Coupled Forward Osmosis for Effluent Water Management at Coal-Fired Power Plants

Rajagopalan¹

2021

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“…In this mode, only nanofraction remains visible, indicating at least 10 6 -fold excess of nanoparticles number over that one of microparticles. Indeed, according to Rayleigh's law, the light scattering intensity increases roughly in proportion to R 6 , where R corresponds to a particle radius [35,36], when R ≤ λ/15. Thus, even traces of larger particles would be visible in the background of dominating small ones in the intensity mode, while in distribution by number they would be lost in noise.…”

Section: Stock Solutions Characterizationmentioning

confidence: 99%

“…Gypsum crystallization has been a matter of intensive research since the end of XIX Century [1]. From the systematic studies of van't Hoff [2] to more recent reports [3][4][5][6], there are over 6000 publications in this field, accounted for by Chemical Abstracts. An interest in gypsum crystallization is due to the broad spectrum of its applications, including both positive and negative ones.…”

Section: Introductionmentioning

confidence: 99%

“…At the same time, the gypsum scale formation is a serious concern in reverse osmosis desalination and in oilfield technologies [7,8]. Thus, it is not surprising that the mechanisms of gypsum nucleation and growth in supersaturated aqueous solutions became a matter of intensive research during the past century [3][4][5][6][9][10][11][12][13][14][15][16][17][18][19][20][21]. These efforts resulted in a Minerals 2020, 10, 1083 2 of 13 very impressive evolution of the views on gypsum formation mechanisms in aqueous solutions from a single-step process within the classical nucleation paradigm [9] to a far more complex picture of the process than previously assumed [3].…”

Section: Introductionmentioning

confidence: 99%

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Initial Stages of Gypsum Nucleation: The Role of “Nano/Microdust”

et al. 2020

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The primary nucleation mechanism of the gypsum in a bulk aqueous medium was identified as a heterogeneous one for 0.05 and 0.03 mol·L−1 CaSO4·2H2O solutions and 25 °C. By means of a particle counter and dynamic light scattering (DLS) technique, solid nano/microimpurities were found, and controlled in stock brines for gypsum supersaturated solutions preparation. It is demonstrated that the common procedure of reagent grade 0.10 mol·L‒1 CaCl2 and Na2SO4 aqueous solutions filtration via 200 nm membranes is capable to reduce the foreign solid microimpurities content (size > 100 nm) from 106 to 103 units in 1 mL, but fails to affect the more numerous nanofraction (size < 100 nm). Thus, the gypsum nucleation takes place in presence of a significant amount of “nano/microcodust” templates, and has a heterogenous character. The induction time, measured by conductivity for the similar supersaturation levels, reveals a well detectable dependence on nano/microdust concentent: an increasing background particle concentration substantially decreases the induction period at a constant saturation state and temperature, and thus increases the nucleation rate. Therefore, the gypsum nucleation reaction starts tentatively through the fast heterogeneous formation of well-defined, primary nuclei via [Ca2+], [SO42‒], and [CaSO4]o species sorption on the surface of “nano/microdust” particles. Thus, the “nano/microdust”, naturally occurring in any high purity chemical, plays a key role in sparingly soluble salts nucleation in the bulk aqueous medium.

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“…One of the most important factors influencing induction time are ion collisions which create crystal nuclei [25]. A larger number of ions (increase in supersaturation level) in the solution increases the probability of nucleation.…”

Section: Introductionmentioning

confidence: 99%

Influence of Supersaturation, Temperature and Rotational Speed on Induction Time of Calcium Sulfate Crystallization

2021

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Calcium sulfate is a very important product of precipitation reactions in various branches of industry. The most common applications include building materials, impression materials in dentistry, immobilizing casts and an inactive ingredient of tablet excipients. It is also used as a drying agent and color glaze. In this paper, influence of various conditions, i.e., substrates concentration (supersaturation), temperature and rotational speed on induction time was investigated. The range of investigated parameters was 0.15–0.35 M for concentration with step of 0.05 M, 298–323 K with step of 5 K for temperature, and 1.67–8.33 s−1 for rotational speed with change every 1.67 s−1. The experiments were performed using visual and turbidimetric methods. It was proven that increase in all three investigated parameters resulted in shorter induction time. The turbidimetric method was found to be more precise, but still insufficient for concentrations below 0.15 M. Moreover, as a result of data analysis, a simple method of induction time calculation was proposed when arbitrary measurements in various concentrations are known.

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Observed Crystallization Induction Time in Seeded Gypsum Crystallization

Cited by 29 publications

References 46 publications

Energy Efficient Waste Heat Coupled Forward Osmosis for Effluent Water Management at Coal-Fired Power Plants

Energy Efficient Waste Heat Coupled Forward Osmosis for Effluent Water Management at Coal-Fired Power Plants

Initial Stages of Gypsum Nucleation: The Role of “Nano/Microdust”

Influence of Supersaturation, Temperature and Rotational Speed on Induction Time of Calcium Sulfate Crystallization

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