Fouling processes present significant challenges in many industries; understanding these processes is crucial for accurate prediction and planning effective mitigation protocols. Composite fouling is ...prevalent in many industrial applications, however, studies of these systems are scarce. We present, for the first time, new insights on the interaction between two common crystallization foulants: BaSO4 and CaCO3. We conducted a series of crystal growth experiments in a plug flow reactor. We used high resolution X-ray micro-computed tomography to visualize the crystal formation. In the first set of experiments, crystals (either BaSO4 or CaCO3) were grown on pristine steel surfaces; these pre-fouled surfaces were then used as substrates for the composite fouling studies. The chemical compositions of the substrates were different from that of the foulant, i.e., either BaSO4 on CaCO3 or CaCO3 on BaSO4. Growth rates were obtained through gravimetric analysis. We characterized surface properties, such as the crystal size distribution, surface coverage, and texture parameters through advanced image analysis. Our results reveal that deposition behaviour depends on complex substrate-foulant interactions. Whereas the net deposition of CaCO3 on a BaSO4 substrate increased with time, significant detachment processes were observed for the reverse case. The increased detachment of BaSO4 on a CaCO3 substrate can be attributed to either the weak interaction within the CaCO3 crystal structure or the CaCO3/steel interface. We also show how substrate properties govern crystal cluster sizes and distribution. The results from this work provide a basis for the development of more comprehensive prediction models.
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•Composite fouling systems were investigated•BaSO4 substrates nearly doubled the growth rate of CaCO3.•CaCO3 substrates promote BaSO4 detachment.•BaSO4 preferentially grew on top of CaCO3 resulting in smaller clusters.
FeCO3 is present as scales in process equipment, corrosion products, geological systems, and carbon storage. It is therefore crucial to investigate the properties of FeCO3 to understand scaling in ...all these systems. However, FeCO3 is not commercially available, and when used in the lab it is either obtained through extraction of geological formations or synthesized in-house. Geologically formed FeCO3 contains multiple impurities, which will affect its overall properties, and the synthesized product is highly sensitive to either oxidation or the synthesis pathways. This work explores the parameter space of a synthesis route routinely and pathways for FeCO3. We characterized the structure of FeCO3 using X-ray powder diffraction and its thermal properties with thermogravimetric analysis and scanning electron microscopy. We show how synthesis parameters influence either the macroscopic or microscopic properties of the synthesized product. Our study serves as a guideline for future research regarding what parameters to choose when synthesizing FeCO3 and what product can be obtained. We herein present a novel fundamental understanding of FeCO3.
•FeCO3 solubility data allow for deeper understanding and prediction of CO2 corrosion and CO2 mineralization.•Limited temperature dependency on FeCO3 solubility.•Extended UNIQUAC cable of describing ...FeCO3 solubility in water.•New calculated Gibbs energy and enthalpy of formation for FeCO3.•Activation energy for FeCO3 dissolution in water.
FeCO3 is present as a CO2 corrosion product in many industrial processes and takes part in the natural CO2 mineralization process. This work presents the solid–liquid equilibrium of the system FeCO3-H2O at 5–120 °C. The FeCO3 solubility showed little temperature dependence. However, temperature affected kinetics as the rate constants for FeCO3 dissolution increased with temperature. The activation energy of FeCO3 dissolution in water was determined to 1.55 kJ mol−1. Gibbs energy of formation was found to be −653.27 kJ mol−1, and the enthalpy of formation for FeCO3 was −710.01 kJ mol−1 using the Extended UNIQUAC model. Extended UNIQUAC could predict the experimental solubility data of FeCO3 in water within an average absolute relative deviation of 0.08.
The data obtained in this study creates the basis for reducing the consequences of CO2 corrosion and increasing knowledge of the CO2 mineralization process.
Crystallization fouling presents a significant challenge in a wide range of industries. Accurate understanding of crystal formation is crucial for planning preventative measures and maximizing the ...effectiveness of maintenance interventions. In this study, we demonstrate that understanding net deposition rates depends on the knowledge of the detachment mechanisms and deposition distribution characteristics. We quantify deposition in a once-through flow set-up and visualize crystal formation through high-resolution X-ray micro-computed tomography scanning. Additionally, we quantify the height distribution of deposited crystals through computed surface texture parameters. Finally, we use computational fluid dynamics, implementing large-eddy simulations turbulence modelling and Eulerian transport of chemical species, to describe bulk and wall reactions and quantify energy and mass transport in turbulent eddies. Results show that attachment and detachment processes depend on fluid hydrodynamics; the influx of material determines the overall deposition to the surface, while the deposition pattern is governed by the surface morphology of the initial surface morphology. Our findings provide a foundation for understanding fouling mechanisms and present a template for developing more accurate prediction models.
•Crystal growth was visualized using high-resolution CT imaging.•CFD simulations were used to describe reactions and mass transport.•Detachment processes are more prominent in low material influx systems.•Surface roughness modulates material influx and affects deposition patterns.•Deposition rates on rough surfaces are higher due to increased nucleation sites.
FeCO
is present as scales in process equipment, corrosion products, geological systems, and carbon storage. It is therefore crucial to investigate the properties of FeCO
to understand scaling in all ...these systems. However, FeCO
is not commercially available, and when used in the lab it is either obtained through extraction of geological formations or synthesized in-house. Geologically formed FeCO
contains multiple impurities, which will affect its overall properties, and the synthesized product is highly sensitive to either oxidation or the synthesis pathways. This work explores the parameter space of a synthesis route routinely and pathways for FeCO
. We characterized the structure of FeCO
using X-ray powder diffraction and its thermal properties with thermogravimetric analysis and scanning electron microscopy. We show how synthesis parameters influence either the macroscopic or microscopic properties of the synthesized product. Our study serves as a guideline for future research regarding what parameters to choose when synthesizing FeCO
and what product can be obtained. We herein present a novel fundamental understanding of FeCO
.
A Call for Standards in the CO 2 Value Chain Neerup, Randi; Løge, Isaac A; Helgason, Kári ...
Environmental science & technology,
12/2022, Letnik:
56, Številka:
24
Journal Article
FeCO3 is a mineral, present in both industrial and natural systems. While the solubility of FeCO3 is determining for CO2 storage, and driving for corrosion, it is not well understood. For the ...development of rigorous modelling, there is a lack of adequate experimental data under relevant conditions to model carbonated systems containing iron.
In this work, the solid-liquid equilibrium (SLE) of the ternary system FeCO3-KCl-H2O was measured at atmospheric pressure at temperatures from 25 to 80 °C. The FeCO3 solubility was studied in aqueous KCl solutions from 3 to 20 wt%. 73 new solubility data points for the systems FeCO3–KCl–H2O are presented together with 73 oxidation data points. Results showed that less than 5% of FeCO3 is oxidized in the electrolyte system. The equilibrium concentration of FeCO3 was obtained after 5–10 days with the fastest equilibrium kinetics obtained at the highest temperature, 80 °C. Temperature had a minor impact on the FeCO3 solubility in aqueous KCl solutions. However, the FeCO3 solubility seemed to slightly decrease with temperature. The solubility data was fitted to a first-order rate equation with molality as driving, to obtain kinetic insights. The dissolution rate decreases as a function of KCl concentrations. In some cases, it was 75 % lower than in NaCl. A rate constant of approximately 0.2 1/day was obtained for most experiments. The FeCO3 solubility and kinetic data obtained in this work will allow for a deeper understanding and better prediction of CO2 corrosion and mineralization, suitable for CO2 storage.
Crystallization fouling poses significant safety, operational, economic, and environmental challenges. Therefore, it is imperative to mitigate crystallization fouling using accurate prediction ...models. Numerous prediction models fail to predict observed fouling rates, and this discrepancy may be attributable to the neglect or oversimplification of detachment processes. In this work, we present a comprehensive review of the significance of detachment processes in crystallization fouling. We first detail the evolution of the incorporation of detachment terms in fouling models. We demonstrate through an extensive review of published experimental studies that current models are oversimplified due to their failure to account for key surface properties. We then address the role of hydrodynamics in detachment processes. We explore the interactions between shear forces and the adhesion strength of the fouling layer, and propose a qualitative three-regime conceptual model to address the lack of consensus in the literature. We provide practical recommendations for fouling mitigation through the intentional promotion of detachment processes. Finally, we identify key areas for further research to develop more accurate models for crystallization fouling processes.
•Detachment processes are poorly incorporated in current crystallization fouling models.•The influence of surfaces and fluid flow on detachment processes is not well understood.•A new three-regime model addresses the complex interactions between surfaces and fluid flow.•Mitigation strategies based on engineering shear stress and surface adhesion are discussed.•Future fouling research areas are proposed.
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