Modeling and Simulation
Yaser Kazemi; Abdullah Irankhah
Abstract
Most of the reactions that occur in microreactors take place on the surface, so it is important to keep the reactants close to the reactive wall. One effective technique in this field is single-phase hydrodynamic focusing. However, this method has a drawback: a high percentage of reactants penetrate ...
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Most of the reactions that occur in microreactors take place on the surface, so it is important to keep the reactants close to the reactive wall. One effective technique in this field is single-phase hydrodynamic focusing. However, this method has a drawback: a high percentage of reactants penetrate into the sheath fluid. To address this issue, the concept of two-phase hydrodynamic focusing is introduced in this study. The main idea is to use a highly viscous sheath fluid to create a barrier against reactant penetration into the sheath flow. To demonstrate the effectiveness of this method, a 3D numerical simulation was performed with an irreversible second-order reaction. The results show that two-phase hydrodynamic focusing increases reaction rates, particularly in downstream regions where the Sherwood number can increase by several orders of magnitude with the use of a highly viscous sheath of liquid. Additionally, it was observed that the use of two-phase hydrodynamic focusing improves efficiency, which is defined as the ratio of solute in the sample flow to the total solute in each cross-section.
Separation Technology,
P. Valeh-e-Sheyda; Sh. Sarlak
Abstract
The increased demand of the world for energy and its reliance on fossil fuels ultimately contribute to the surge in the levels of carbon dioxide in the atmosphere. To achieve a green, efficient carbon capture, a novel multi-component amine-amino acid solvent including methyldiethanolamine (MDEA), diisopropanolamine ...
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The increased demand of the world for energy and its reliance on fossil fuels ultimately contribute to the surge in the levels of carbon dioxide in the atmosphere. To achieve a green, efficient carbon capture, a novel multi-component amine-amino acid solvent including methyldiethanolamine (MDEA), diisopropanolamine (DIPA), and Arginine (ARG) was designated for the CO2 absorption in a T-microreactor. The potential absorption of the aqueous solutions of the desired mixed amines has been assessed through the CO2 absorption percentage (AP) and the total volumetric gas-phase mass transfer coefficient (TGMTC) over a wide range of the gas flow rates (60-240 mL/min), solvent flow rates (2-6 mL/min), under the three mixing concentrations of MDEA: DIPA: ARG (28:8:4), (28:6:6), and (28:4:8)) wt%. The research findings demonstrate an increment of 31% in the absorption percentage of CO2 by reducing DIPA to 4 wt% and raising the concentration of arginine to 8 wt% in the ternary amine solutions. Additionally, the highest mass transfer coefficient of 38.06 (kmol/m3.h.kPa) was achieved utilizing the aqueous solution of MDEA+DIPA+ARG (28+4+8) wt%.
Reaction Engineering, Kinetics and Catalysts,
M. Basiri; M. Rahimi; H. Babaei Mohammadi
Volume 13, Issue 2 , April 2016, , Pages 22-32
Abstract
The ultrasound-assisted (UA) soybean oil methanolysis using KOH as a catalyst was studied at different reaction conditions in a microreactor. Box–Behnken experimental design, with three variables, was performed and the effects of three reaction variables i.e. reaction temperature, catalyst concentration ...
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The ultrasound-assisted (UA) soybean oil methanolysis using KOH as a catalyst was studied at different reaction conditions in a microreactor. Box–Behnken experimental design, with three variables, was performed and the effects of three reaction variables i.e. reaction temperature, catalyst concentration and the methanol-to-oil molar ratio on fatty acid methyl ester (FAME) yield were evaluated by method of analysis of variance (ANOVA) and multiple regression. A quadratic polynomial model was obtained to predict the methyl ester yield. A yield of 97.1% for methyl ester was obtained at the deduced optimal conditions: reaction temperature of 47 °C, KOH catalyst concentration of 1.29% (w/w) and methanol-to-oil molar ratio of 6:1. Validation experiments confirmed the validity of the predicted model. At the optimal operation condition for the ultrasonic process, a higher yield of methyl esters was obtained in comparison with that of the non-ultrasonic layout. The results show that UA transesterification in microreactor minimizes the reaction time and temperature, alcohol-to-oil molar ratio as well as energy consumption.