scholarly journals Thermodynamic and Kinetic Modelling of Scales Formation at the Soultz-sous-Forêts Geothermal Power Plant

Geosciences ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 483
Author(s):  
Pierce Kunan ◽  
Guillaume Ravier ◽  
Eléonore Dalmais ◽  
Marion Ducousso ◽  
Pierre Cezac
Keyword(s):  
Kinetic Model ◽  
Thermodynamic Model ◽  
Chemical Elements ◽  
Kinetic Modelling ◽  
Current Model ◽  
Geothermal System ◽  
Upper Rhine Graben ◽  
Metal Sulfate ◽  
Geothermal Plant ◽  
Scaling Phenomenon

Geothermal energy has been a subject of great interest since the 1990s in the Upper Rhine Graben (URG), where the first European Enhanced Geothermal System (EGS) pilot site has been developed, in Soultz-sous-Forêts (SsF), France. Several studies have already been conducted on scales occurring at the reinjection side at the geothermal plants located in the URG. It has been observed that the composition of the scales changes as chemical treatment is applied to inhibit metal sulfate. The purpose of this study was to model the scaling phenomenon occurring in the surface pipes and the heat exchangers at the SsF geothermal plant. PhreeqC, a geochemical modelling software, was used to reproduce the scaling observations in the geothermal plant during exploitation. A suitable database was chosen based on the availability of chemical elements, minerals, and gas. A thermodynamic model and a kinetic model were proposed for modelling the scaling phenomenon. The thermodynamic model gave insight on possible minerals precipitated while the kinetic model, after modifying the initial rates equation, produced results that were close to the expected scale composition at the SsF geothermal plant. Additional laboratory studies on the kinetics of the scales are proposed to complement the current model.

Kinetic modelling of the photocatalytic inactivation of bacteria

2010 ◽  
Vol 61 (6) ◽  
pp. 1547-1553 ◽  
Author(s):  
Javier Marugán ◽  
Rafael van Grieken ◽  
Alberto E. Cassano ◽  
Orlando M. Alfano
Keyword(s):  
Kinetic Model ◽  
Kinetic Parameters ◽  
Catalyst Concentration ◽  
Kinetic Modelling ◽  
Kinetic Constant ◽  
Water Disinfection ◽  
Radiation Absorption ◽  
Simple Modification ◽  
Model Based ◽  
Photocatalytic Inactivation

This work analyzes the kinetic modelling of the photocatalytic inactivation of E. coli in water using different types of kinetic models; from an empirical equation to an intrinsic kinetic model including explicit radiation absorption effects. Simple empirical equations lead to lower fitting errors, but require a total of 12 parameters to reproduce the results of four inactivation curves when the catalyst concentration was increased. Moreover, these parameters have no physical meaning and cannot be extrapolated to different experimental conditions. The use of a pseudo-mechanistic model based on a simplified reaction mechanism reduces the number of required kinetic parameters to 6, being the kinetic constant the only parameter that depends on the catalyst concentration. Finally, a simple modification of a kinetic model based on the intrinsic mechanism of photocatalytic reactions including explicit radiation absorption effects achieved the fitting of all the experiments with only three parameters. The main advantage of this approach is that the kinetic parameters estimated for the model become independent of the irradiation form, as well as the reactor size and its geometrical configuration, providing the necessary information for scaling-up and design of commercial-scale photoreactors for water disinfection.

scholarly journals A Calculation Model of the General Theory of Interaction Potentials for Stoichiometric Lanthanide Type Crystals: Applications to the Cs2KLnCl6 System

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Andres Soto ◽  
Shanavas Shajahan ◽  
Roberto Acevedo
Keyword(s):  
General Theory ◽  
Chemical Elements ◽  
Current Model ◽  
Theoretical Models ◽  
Calculation Model ◽  
Lanthanide Ions ◽  
Interaction Potentials ◽  
Model Calculations ◽  
Advantages And Disadvantages ◽  
Semi Empirical

AbstractThis article aims to develop a generalized model calculation model to be applicable to the general theory of interaction potentials with reference to the stoichiometric elpasolite type crystals. In this study, we have chosen to report both a theoretical model and a calculation strategy to undertake semi empirical calculations of thermodynamic properties, such as reticular energies and heats of formation for the series of systems such as: Cs2KLnCl6. We have also carried out quite a number of calculations for a variety of systems such as: Cs2NaLnF6, Cs2NaLnCl6, Cs2NaLnBr6, Rb2NaLnF6and Cs2KLnF6 in the Fm3m space group since we aim to check the strengths and weaknesses of our model calculations. We have analyzed a substantial number of approximate theoretical models and have carried a formidable amount of computing simulations to estimate the reticular energies and the corresponding heat of formation for these type of crystal using a semi empirical model. We made use of the thermodynamic cycles of Born-Haber so as to get a broad view with reference to the accuracy of our semi empirical theoretical models. The problem itself is quite challenging since we have focused our attention upon trivalent lanthanide ions $$L{n}^{+3}$$Ln+3 in the first inner transition series of the chemical elements: (Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). There are a significant amount of outstanding research works published in the literature with reference to structural analysis, one photon spectroscopy, vibrionic intensity model calculations and generalized models to deal with these kind of complex crystals. The calculated energy values associated with these observables seems to be most reasonable, and these follow the expected trends, as may be expected on both theoretical and experimental grounds. Both, the advantages and disadvantages of the current model calculations, have been tested against other previous calculations performed for this type of complex systems. It is of a paramount importance, the results obtained and reported in this article with regards to convergence tests as well as some master equations derived to account for the various contributions to the total energy. The Born-Mayer-Buckingham potential is carefully examined with reference to these lanthanide type crystals Cs2KLnCl6. Finally but not at last, the most likely sources for improvement are carefully discussed in this work. We strongly believe that there is enough room for improvement and have therefore initiated a new research program of activities tackling systems of well-known optical and structural properties.

Depth-dependent analysis of fracture patterns inferred from image logs and cores in crystalline rocks

2020 ◽  
Author(s):  
Mohammad Javad Afshari Moein
Keyword(s):  
Spatial Distribution ◽  
Correlation Dimension ◽  
Numerical Models ◽  
Fracture Network ◽  
Crystalline Rocks ◽  
Geothermal System ◽  
Upper Rhine Graben ◽  
Enhanced Geothermal System ◽  
Fracture Density ◽  
Fracture Patterns

<p>Enhanced Geothermal System (EGS) development requires an accurate fracture network characterization. The knowledge on the fracture network is fundamental for setting up numerical models to simulate the activated processes in hydraulic stimulation experiments. However, direct measurement of fracture network properties at great depth is limited to the data from exploration wells. Geophysical logging techniques and continuous coring, if available, provide the location and orientation of fractures that intersect the wellbore. The statistical parameters derived from borehole datasets (either from image logs or cores) constrain stochastic realizations of the rock mass, known as Discrete Fracture Network (DFN) models. However, accurate parametrization of DFN models requires sufficient knowledge on the depth-dependent spatial distribution of fractures in the earth’s crust.</p><p>This analysis includes a unique collection of fracture datasets from six deep (i.e. 2-5 km depth) boreholes drilled into crystalline basement rocks at the same tectonic settings. All the wells were drilled in the Upper Rhine Graben in Soultz-sous-Forêts Enhanced Geothermal System, France, except the well that was drilled in Basel geothermal project, Switzerland. The datasets included both borehole image logs and core samples, which have a higher resolution. Two-point correlation function was selected to characterize the power-law scaling of fracture patterns. The correlation dimension of spatial patterns showed no systematic variations with depth at one standard deviation level of uncertainty in moving windows of sufficient number of fractures along any of the boreholes. This implies that a single correlation dimension is sufficient to address the global scaling properties of the fractures in crystalline rocks. One could also anticipate the spatial distribution of deeper reservoir conditions from shallower datasets. On the contrary, the fracture density showed some variations with depth that are sometimes consistent with changes in lithology and geological settings at the time of fracture formation.</p>

Employing Simulated Data to Illustrate an Important Cause of the ‘Steepling’ Effect in Breath Alcohol Analysis

1994 ◽  
Vol 34 (4) ◽  
pp. 321-323 ◽  
Author(s):  
Rod G. Gullberg
Keyword(s):  
Kinetic Model ◽  
Data Collection ◽  
Nonlinear Regression ◽  
Kinetic Modelling ◽  
Analytical Data ◽  
Simulated Data ◽  
Breath Alcohol ◽  
Random Samples ◽  
The Mean ◽  
Over Time

The ‘steepling’ effect (large excursions in analytical data over time) is a debated issue in forensic breath alcohol analysis with various explanations being postulated. Simulated breath alcohol data was generated according to a hypothetical kinetic model where single random samples as well as means of duplicate random samples were plotted with respect to time at 0.2 hour intervals. In addition, the simulated data was compared when both two or more digit treatment was employed. Results showed the occurrence of significant noise or ‘steepling’ when single, two-digit breath alcohol samples were employed as compared to a four-digit mean computed from three-digit duplicates. The magnitude of variability was quantified by means of nonlinear regression resulting in the residual sum of squares (RSS) = 0.00202 for the single analysis and RSS = 0.00053 for the mean of duplicates. The method of data collection and treatment appears to contribute significantly to the ‘steepling’ phenomenon. Intuitively, replicate analyses reduce variability and allow for more accurate kinetic modelling employing breath alcohol analysis.

Kinetic Modelling of the Deposition of SiC from Methyltrichlorosilane

1991 ◽  
Vol 250 ◽  
Author(s):  
Stratis V. Sotirchos ◽  
George D. Papasouliotis
Keyword(s):  
Silicon Carbide ◽  
Kinetic Model ◽  
Gas Phase ◽  
Kinetic Modelling ◽  
Reaction Model ◽  
Heterogeneous Reactions ◽  
Reactor Model ◽  
Preliminary Results ◽  
Homogeneous Reactions

AbstractA kinetic model is presented for the deposition of silicon carbide through decomposition of methyltrichlorosilane (MTS). The developed model includes gas phase (homogeneous) reactions that lead to formation of deposition precursors and surface (heterogeneous) reactions that lead or can lead to deposition of silicon carbide, silicon, and carbon. The kinetic model is incorporated in a transport and reaction model for a tubular hot-wall reactor, and the overall reactor model is used to obtain some preliminary results on the effects of pressure and distance in the reactor on the rate of deposition and the composition of the deposit. The results show that the model can reproduce most of the experimental observations of the literature.

scholarly journals Kinetic Modelling and Determination of Octyl Phenol Ethoxylate (OPE) and Bisphenol A (BPA) (used as plastic additives) Inhibition Constants for Nitrogen Conversion

2021 ◽  
Keyword(s):  
Kinetic Model ◽  
Bisphenol A ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Kinetic Modelling ◽  
Ammonium Nitrogen ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Octyl Phenol ◽  
Inhibition Constants

<p>Conversion of ammonia to nitrate is sensitive to a number of inhibitors. There is limited information on the nitrification inhibition coefficient and kinetic model in the current literature. Octyl Phenol Ethoxylate (OPE) and Bisphenol A (BPA) inhibition constants were found in nitrogen removal using an activated sludge system. Firstly, OPE and BPA free wastewater was used to determine the optimum operating conditions. The effect of OPE and BPA concentration on system performance was investigated. The ammonium removal rate was less affected by lower OPE and BPA concentrations. When the BPA and OPE concentrations were increased from 0 mg/L to 30 mg/L, the outlet ammonium nitrogen concentrations were increased respectively from 2.8 mg/L to 49.8 mg/L and from 2.6 mg/L to 20.40 mg/L. Due to the inhibition created by these compounds on Nitrobacter, nitrite nitrogen increased in the medium. As the OPE and BPA concentrations increased, the conversion rate of the ammonium nitrogen into nitrate decreased. Based on the experimental results, a kinetic model was developed, and the OPE and BPA inhibition constants (KOPE and KBPA) were found to be 40.7 mg/L and 11.76 mg/L, respectively. In nitrogen removal, BPA created a higher inhibition effect in comparison to OPE.</p>

scholarly journals Kinetic modelling of quantitative proteome data predicts metabolic reprogramming of liver cancer

2019 ◽  
Vol 122 (2) ◽  
pp. 233-244 ◽  
Author(s):  
Nikolaus Berndt ◽  
Antje Egners ◽  
Guido Mastrobuoni ◽  
Olga Vvedenskaya ◽  
Athanassios Fragoulis ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Liver Cancer ◽  
Metabolic Pathways ◽  
Kinetic Modelling ◽  
Central Carbon Metabolism ◽  
Metabolic Reprogramming ◽  
Maximal Velocity ◽  
Proteomics Data

Abstract Background Metabolic alterations can serve as targets for diagnosis and cancer therapy. Due to the highly complex regulation of cellular metabolism, definite identification of metabolic pathway alterations remains challenging and requires sophisticated experimentation. Methods We applied a comprehensive kinetic model of the central carbon metabolism (CCM) to characterise metabolic reprogramming in murine liver cancer. Results We show that relative differences of protein abundances of metabolic enzymes obtained by mass spectrometry can be used to assess their maximal velocity values. Model simulations predicted tumour-specific alterations of various components of the CCM, a selected number of which were subsequently verified by in vitro and in vivo experiments. Furthermore, we demonstrate the ability of the kinetic model to identify metabolic pathways whose inhibition results in selective tumour cell killing. Conclusions Our systems biology approach establishes that combining cellular experimentation with computer simulations of physiology-based metabolic models enables a comprehensive understanding of deregulated energetics in cancer. We propose that modelling proteomics data from human HCC with our approach will enable an individualised metabolic profiling of tumours and predictions of the efficacy of drug therapies targeting specific metabolic pathways.

Integrated chemical–physical processes kinetic modelling of multiple mineral precipitation problems

2006 ◽  
Vol 53 (12) ◽  
pp. 65-73 ◽  
Author(s):  
G.A. Ekama ◽  
M.C. Wentzel ◽  
R.E. Loewenthal
Keyword(s):  
Kinetic Model ◽  
Kinetic Modelling ◽  
Close Correlation ◽  
Weak Acid ◽  
Time Profile ◽  
Swine Wastewater ◽  
Algebraic Models ◽  
Acid Base ◽  
Final Equilibrium State ◽  
Multiple Mineral

A three-phase (aqueous/gas/solid) mixed weak acid/base chemistry kinetic model is applied to evaluate the processes operative in the aeration treatment of swine wastewater (SWW) and sewage sludge anaerobic digester liquor (ADL). In both applications, with a single set of constants (except for the aeration rates which are situation specific), close correlation could be obtained between predicted and measured data, except for the Ca concentration–time profile in the SWW. For this wastewater, the model application highlighted an inconsistency in the measured Ca data which could not be resolved; this illustrates the value of a mass balance-based model in evaluating experimental data. From the model applications, in both wastewaters the dominant minerals precipitating are struvite and amorphous calcium phosphate (ACP), which precipitate simultaneously competing for the same species, P. The absolute and relative masses of the two precipitants are governed by the initial solution state (e.g. total inorganic C (CT), Mg, Ca and P concentrations), their relative precipitation rates (struvite &gt; ACP) and the system conditions imposed (aeration rates and time applied). It is concluded that the kinetic model is able to predict correctly the time-dependent weak acid/base chemistry reactions and final equilibrium state for situations where multiple minerals competing for the same species precipitate simultaneously or sequentially, a deficiency in traditional equilibrium chemistry-based algebraic models.

Thermodynamic Model for Acidic Metal Sulfate from Solubility Data

REWAS 2013 ◽  
2013 ◽  
pp. 145-154
Author(s):  
Petri Kobylin ◽  
Hannu Sippola ◽  
Pekka Taskinen
Keyword(s):  
Thermodynamic Model ◽  
Solubility Data ◽  
Metal Sulfate

Study of Complex Reactions under Rapid Deactivation -- Improvements in the Reaction Equipment and in the Methodology for Kinetic Calculation

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Diana Mier ◽  
Andrés Tomás Aguayo ◽  
Alaitz Atutxa ◽  
Ana G Gayubo ◽  
Javier Bilbao
Keyword(s):  
Data Analysis ◽  
Kinetic Equation ◽  
Kinetic Model ◽  
Technological Development ◽  
Kinetic Modelling ◽  
Past History ◽  
Accurate Determination ◽  
Process Conditions ◽  
Product Analysis ◽  
Simulation And Optimization

The technological development of catalytic processes under rapid deactivation requires the rigorous calculation of the deactivation kinetic equation in order to be useful in the simulation and optimization of industrial processes. Accordingly, suitable equipment for reaction and product analysis and a rigorous methodology for kinetic data analysis are required. These aspects are approached in this paper using the transformation of methanol into olefins on a SAPO-18 as the model reaction. In this reaction, deactivation is rapid and there is also an initiation period depending on process conditions. The correct use of gas chromatography allows for improving the collection of experimental data of composition with time-on-stream, given that, on the one hand, it minimizes the time required for analysis (4 min), and on the other, a better homogenization of the reaction product sample is achieved, which allows for a more accurate determination of the composition corresponding to a given time-on-stream. Furthermore, the rigorous kinetic modelling of deactivation requires a data analysis methodology that considers the past history of the catalyst and an activity to be defined based on a rigorous physical meaning. Accordingly, the concept of the integrated kinetic model has been used in this paper, whose basis is the calculation of kinetic parameters by simultaneously solving the zero time-on-stream kinetic model and the kinetic equation for deactivation.

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