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A A Attar - One of the best experts on this subject based on the ideXlab platform.
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corrosion of alloy steel in 30 ethylene glycol solution and cro24 under Hydrodynamic Condition
Journal of Iron and Steel Research International, 2013Co-Authors: Niknejad M Khomami, I Danaee, A A Attar, M PeykariAbstract:The electrochemical behavior of steel alloy in 30% ethylene glycol-water solution at different solution rotating speeds was investigated by polarization curves and AC impedance measurements. The results obtained showed that corrosion rate did not change significantly at different rotating speeds. The effect of chromate as the inhibitor was studied and high inhibition efficiency was obtained. It was found that surface passivation occurred in the presence of the inhibitor. The inhibiting effect of the chromate was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Cl− and the adsorption isotherm basically obeys the Langmuir adsorption isotherm. Thermodynamic parameters for inhibitor adsorption were determined and results reveal that the adsorption process is spontaneous.
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corrosion of aisi 4130 steel alloy under Hydrodynamic Condition in ethylene glycol water no2 solution
Journal of Materials Science & Technology, 2013Co-Authors: I Danaee, Niknejad M Khomami, A A AttarAbstract:The electrochemical behavior of steel alloy in ethylene glycol–water mixture at different solution rotating speeds was investigated by polarization curves and AC impedance measurements (EIS). The results obtained showed that corrosion rate was not changed significantly at different rotating speeds and was decreased with increasing ethylene glycol concentration. The effect of nitrite as an inhibitor was studied and high inhibition efficiency was obtained. It was found that surface passivation occurred in the presence of inhibitor. The inhibiting effect of the nitrite was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Cl− ions and the adsorption isotherm basically obeys the Flory–Huggins adsorption isotherm. Thermodynamic parameters for steel corrosion and inhibitor adsorption were determined, which revealed that the adsorption process is spontaneous.
I Danaee - One of the best experts on this subject based on the ideXlab platform.
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corrosion of alloy steel in 30 ethylene glycol solution and cro24 under Hydrodynamic Condition
Journal of Iron and Steel Research International, 2013Co-Authors: Niknejad M Khomami, I Danaee, A A Attar, M PeykariAbstract:The electrochemical behavior of steel alloy in 30% ethylene glycol-water solution at different solution rotating speeds was investigated by polarization curves and AC impedance measurements. The results obtained showed that corrosion rate did not change significantly at different rotating speeds. The effect of chromate as the inhibitor was studied and high inhibition efficiency was obtained. It was found that surface passivation occurred in the presence of the inhibitor. The inhibiting effect of the chromate was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Cl− and the adsorption isotherm basically obeys the Langmuir adsorption isotherm. Thermodynamic parameters for inhibitor adsorption were determined and results reveal that the adsorption process is spontaneous.
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corrosion of aisi 4130 steel alloy under Hydrodynamic Condition in ethylene glycol water no2 solution
Journal of Materials Science & Technology, 2013Co-Authors: I Danaee, Niknejad M Khomami, A A AttarAbstract:The electrochemical behavior of steel alloy in ethylene glycol–water mixture at different solution rotating speeds was investigated by polarization curves and AC impedance measurements (EIS). The results obtained showed that corrosion rate was not changed significantly at different rotating speeds and was decreased with increasing ethylene glycol concentration. The effect of nitrite as an inhibitor was studied and high inhibition efficiency was obtained. It was found that surface passivation occurred in the presence of inhibitor. The inhibiting effect of the nitrite was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Cl− ions and the adsorption isotherm basically obeys the Flory–Huggins adsorption isotherm. Thermodynamic parameters for steel corrosion and inhibitor adsorption were determined, which revealed that the adsorption process is spontaneous.
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effect of ethylenediamine on corrosion of aisi 4130 steel alloy in 30 ethylene glycol solution under static and Hydrodynamic Condition
Materialwissenschaft Und Werkstofftechnik, 2012Co-Authors: I Danaee, Niknejad M KhomamiAbstract:The electrochemical behavior of steel alloy in 30% ethylene glycol-water solution at different solution rotating speeds was investigated by polarization curves and AC impedance measurements. The results obtained showed that corrosion rate was not changed significantly in different rotating speed. The effect of ethylenediamine as inhibitor was studied and high inhibition efficiency was obtained. It was found that inhibitor adsorption was occurred in presence of inhibitor. The inhibiting effect of the ethylenediamine was explained on the basis of the competitive adsorption between the inhibitor and the aggressive Cl– ions and the adsorption isotherm basically obeys the Langmuir adsorption isotherm. Thermodynamic parameters for inhibitor adsorption were determined and reveal that the adsorption process is spontaneous.
Niknejad M Khomami - One of the best experts on this subject based on the ideXlab platform.
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corrosion of alloy steel in 30 ethylene glycol solution and cro24 under Hydrodynamic Condition
Journal of Iron and Steel Research International, 2013Co-Authors: Niknejad M Khomami, I Danaee, A A Attar, M PeykariAbstract:The electrochemical behavior of steel alloy in 30% ethylene glycol-water solution at different solution rotating speeds was investigated by polarization curves and AC impedance measurements. The results obtained showed that corrosion rate did not change significantly at different rotating speeds. The effect of chromate as the inhibitor was studied and high inhibition efficiency was obtained. It was found that surface passivation occurred in the presence of the inhibitor. The inhibiting effect of the chromate was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Cl− and the adsorption isotherm basically obeys the Langmuir adsorption isotherm. Thermodynamic parameters for inhibitor adsorption were determined and results reveal that the adsorption process is spontaneous.
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corrosion of aisi 4130 steel alloy under Hydrodynamic Condition in ethylene glycol water no2 solution
Journal of Materials Science & Technology, 2013Co-Authors: I Danaee, Niknejad M Khomami, A A AttarAbstract:The electrochemical behavior of steel alloy in ethylene glycol–water mixture at different solution rotating speeds was investigated by polarization curves and AC impedance measurements (EIS). The results obtained showed that corrosion rate was not changed significantly at different rotating speeds and was decreased with increasing ethylene glycol concentration. The effect of nitrite as an inhibitor was studied and high inhibition efficiency was obtained. It was found that surface passivation occurred in the presence of inhibitor. The inhibiting effect of the nitrite was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Cl− ions and the adsorption isotherm basically obeys the Flory–Huggins adsorption isotherm. Thermodynamic parameters for steel corrosion and inhibitor adsorption were determined, which revealed that the adsorption process is spontaneous.
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effect of ethylenediamine on corrosion of aisi 4130 steel alloy in 30 ethylene glycol solution under static and Hydrodynamic Condition
Materialwissenschaft Und Werkstofftechnik, 2012Co-Authors: I Danaee, Niknejad M KhomamiAbstract:The electrochemical behavior of steel alloy in 30% ethylene glycol-water solution at different solution rotating speeds was investigated by polarization curves and AC impedance measurements. The results obtained showed that corrosion rate was not changed significantly in different rotating speed. The effect of ethylenediamine as inhibitor was studied and high inhibition efficiency was obtained. It was found that inhibitor adsorption was occurred in presence of inhibitor. The inhibiting effect of the ethylenediamine was explained on the basis of the competitive adsorption between the inhibitor and the aggressive Cl– ions and the adsorption isotherm basically obeys the Langmuir adsorption isotherm. Thermodynamic parameters for inhibitor adsorption were determined and reveal that the adsorption process is spontaneous.
Weiguo Xie - One of the best experts on this subject based on the ideXlab platform.
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development of scale up enabling technique using constant temperature anemometry for turbulence measurement in flotation cells
Minerals Engineering, 2020Co-Authors: E Amini, Weiguo XieAbstract:Abstract The success of flotation scale-up depends on understanding of the Hydrodynamic Condition of flotation cells at different scales and design specifications. In order to achieve this, it is very important to measure Hydrodynamic parameters such as fluid velocity, turbulent kinetic energy (TKE) and turbulent kinetic energy dissipation rate (TKEDR) in flotation cells. There are many methods that are available to measure velocity and velocity fluctuations in turbulent fluids, especially for single-phase flows or two-phase flows, however very few of them can be used for flotation cells. In this study, constant temperature anemometry (CTA) and power measurement methods were used to measure the parameters in two scales of flotation cells. Acceptable correlation between the CTA measurements and the TKEDR has been found under different Hydrodynamic Conditions in both cells. It shows that this measurement technique enables the scale-up analysis for turbulence in flotation cells.
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influence of flotation cell Hydrodynamics on the flotation kinetics and scale up part 2 introducing turbulence parameters to improve predictions
Minerals Engineering, 2017Co-Authors: E Amini, D J Bradshaw, Weiguo XieAbstract:The AMIRA P9 model has floatability (P) as the ore property which is considered to remain constant in different flotation cell sizes under different Hydrodynamic Conditions. However, in this study increasing the power input increased the P value, especially in finer particle size classes (below 75 μm). Acceptable explanations for the floatability variations, as a result of Hydrodynamic Condition variations in the flotation cells, have been sought by looking at the literature and the results obtained in this study were published in part one of this manuscript. To improve the accuracy of the AMIRA P9 flotation model in predicting flotation rate constant (k) and to improve the consistency of ore property, measurable and appropriate turbulence parameters were sought to be incorporated into the model. Therefore, two dimensionless turbulence parameters ae and EVF, derived from practical measurements, were formulated and introduced to the AMIRA P9 model. The modified ore floatability parameter, P″, was demonstrated to be a more consistent characterisation of the ore property than P and both the accuracy and precision of the k prediction improved for a variety of Hydrodynamic Conditions of flotation cells.
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influence of flotation cell Hydrodynamics on the flotation kinetics and scale up part 1 Hydrodynamic parameter measurements and ore property determination
Minerals Engineering, 2016Co-Authors: E Amini, D J Bradshaw, Weiguo XieAbstract:Abstract Developing practical measurement methodologies to characterise Hydrodynamic Conditions of flotation cells of any size, and the provision of useful data for flotation modelling, are a challenge. In this study, several measurement instruments such as a power meter, hot-wire anemometer, bubble sizer, air flow meter and viscometer were used to characterise the Hydrodynamic Condition inside two different flotation cells (5 L and 60 L) making it possible to compare the Hydrodynamic Conditions of a 5 L (lab scale) cell with a 60 L (pilot scale) flotation cell. As a result, power input, energy dissipation rate, turbulent kinetic energy, bubble size and air flow parameters were obtained for 12 different Hydrodynamic Conditions in the cells. It has been assumed that P (ore floatability) in the AMIRA P9 model remains constant over a wide range of bubble surface area flux (Sb) regardless of the amount of power introduced into a flotation cell. Therefore, increasing the impeller speed in the cell does not have any effect on the P value if P is the true ore property. However, flotation test work was conducted in the above mentioned different Hydrodynamic Conditions in both cells, and shows that by increasing the power input the P value is also increased, especially for particle size classes below 75 μm in both cells. P, in its current form, cannot therefore be the true ore property and is influenced by cell Hydrodynamics. It should be mentioned that the current AMIRA P9 model still remains a useful model to simulate a plant operation under some circumstances not far from its original design state. However, in order to improve the scale up capability from lab scale flotation tests, it is necessary to incorporate the measured Hydrodynamic parameters into the AMIRA P9 model.
Greg Leslie - One of the best experts on this subject based on the ideXlab platform.
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shear stress in a pressure driven membrane system and its impact on membrane fouling from a Hydrodynamic Condition perspective a review
Journal of Chemical Technology & Biotechnology, 2017Co-Authors: Yuan Wang, Greg Leslie, Heng LiangAbstract:Pressure-driven membrane technology has gained increasing popularity in municipal/domestic and industrial wastewater treatment, desalination, and water reclamation. Careful manipulation of surface shear stress, which plays a vital role in membrane fouling control from a purely Hydrodynamic perspective, can minimise concentration polarisation of solute on flat sheet membranes, or enhance the particle back transport from hollow fibre membranes. This review considers the techniques to generate turbulence and shear at the membrane surface, the magnitude of shear stress, and the experimental, as well as numerical methods for evaluation of shear stress. The findings are presented in terms of the amount of shear stress reported to control membrane fouling in these systems. Operational disadvantages of fouling control via application of shear stress occur while changing the properties of the solute or particles, such as cell breakup, bacterial population change, or shear stress classification. The literature teaches that future developments on shear stress for membrane systems must be addressed, in addition to energy consumption, shear stress distribution and the development of combined analytical methods to characterise and visualise shear in situ for different membrane configurations. © 2016 Society of Chemical Industry
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cfd simulations of membrane filtration zone in a submerged hollow fibre membrane bioreactor using a porous media approach
Journal of Membrane Science, 2010Co-Authors: Yuan Wang, M Brannock, Shane Cox, Greg LeslieAbstract:Abstract The current membrane bioreactor (MBR) design methods and the popular bio-kinetic models rely on the assumption that membrane bioreactor is completely mixed, neglecting the real Hydrodynamic Condition within the reactor. MBRs differ from conventional reactors in so far as the spatial distribution of reactor discharge points is very broad for an MBR compared with a conventional bioreactor. Computational Fluid Dynamics (CFD) provides a possibility to investigate the Hydrodynamic behaviour of large scale MBRs. The CFD modelling of whole MBR plant requires a macro-scale approximation which can keep the mesh size and computation effort within the reasonable limit. However, the simulation of the flow behaviour surrounding the membranes requires high mesh resolutions and hence large element numbers. Therefore, it is impossible to model each individual hollow fibre using the Navier–Stokes equations as it is too computationally costly. In this paper, the effects of Siemens Memcor Memjet ® hollow fibre membrane bundle on flow field were transferred to a porous media model. This porous media model was coupled with a three-dimensional multiphase model to account for the Hydrodynamic behaviour of a full-scale submerged MBR. An experimental approach was developed to calibrate the inertial loss caused by the hollow fibre bundle against various liquid velocities at different flow direction and fluid viscosity. The experimentally determined inertial losses were compared against those estimated from the empirical correlations for tube banks. These experimental calibrations were then applied to the porous media model. Significant improvement on the Hydrodynamic descriptions was observed by coupling the porous media model compared with the previous developed MBR CFD model.