الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Microreactors have gained great interest in research due to their high effectiveness compared to regular reactors. They have been involved in many applications, such as the production of fuel and medicine and pharmaceutical applications. The most influential part of the microreactor is the micromixer which is responsible for enhancing the rates of heat and mass transfer which directly affects the whole reactor performance. Developing microreactors that are similar to body organs, may be later used as a platform to mimic the organ itself on a microchip. In the present study, a novel planar micromixer inspired by hepatic sinusoids is presented. A computational model is built to study the effects of geometric parameters variance on the micromixer performance. The micromixer is fabricated from Polydimethylsiloxane (PDMS) using photolithography technique, and experiments have been conducted to validate the computational model. Improved micromixer design is attained that is suitable for stratified flow. Results show promising performance over the studied Reynolds (Re) and Peclet (Pe) numbers range, especially at low values of Re number. Mixing qualities up to 99% have been attained with pressure DROP lower than 5000 Pa. The mixing performance is then investigated using Villermaux–Dushman protocol. The protocol is an iodide/iodate chemical test reaction that relies on testing the absorbance of the product at 352 nm as an indication of the formation of triiodide. The investigation is carried out at low flow rates ranges from 0.5 to 3 ml/min. The fabricated device has proven to give satisfactory performance and is easy to be fabricated as it consists of a single layer. To test the micromixer in different applications, two applications are considered: dye degradation and drug production. A microreactor system is constructed to experimentally test the fabricated device in Methylene blue degradation using titanium dioxide (TiO2) photocatalyst activated with ultraviolet lamp of wavelength 365 nm. Purification of water using photocatalysis is considered a promising technology that attract the industrial community. Different operating conditions are investigated including flow rate, Methylene blue concentration, and TiO2 concentration. 3 different dye concentrations are used (10 ppm, 20 ppm, and 30 ppm) with 3 different photocatalyst concentrations (100 ppm, 300 ppm, and 500 ppm). The flow rate has a span from 0.25 ml/min to 1 ml/min. Experiments are conducted to determine best operating conditions. Results show that the microreactor system can be effectively used in dye degradation with a very small residence time. A degradation of over 95% was reached at a TiO2 concentration of 300 ppm and a flow rate of 0.25 ml/min for all tested dye concentrations. Finally, A microtube reactor system is constructed to produce (Z)-5-(4-hydroxybenzylidene)thiazolidine-2,4-dione intermediate drug with the fabricated micromixer used as the part responsible of mixing the reactants in early stages. (Z)-5-(4-hydroxybenzylidene)thiazolidine-2,4-dione is an intermediate drug that belongs to glitazones. A batch system is also constructed for the purpose of comparison. Thiazolidine-2,4-dione (TZD) and p-hydroxybenzaldehyde are used as the main reactants while two compounds are used as catalysts; diethylamine and piperdine. Effects of different parameters such as initial reactants concentration, catalyst concentration, and flow rate and residence time on the product yield and the pressure DROP across the micromixer are investigated. Analysis of the collected samples is done using different characterization methods such as High Pressure Liquid chromatography, Thermogravimetric/Differential Thermal Analysis X-ray diffraction spectroscopy, Fourier Transform Infrared spectroscopy, and carbon and proton Nuclear magnetic resonance spectra. The microtube reactor system has proven to be more efficient than the batch system. The maximum yield obtained from the batch system is 92% using piperdine as a catalyst after 12 hr run compared with 97% obtained from microtube reactor system with a residence time of only 22 min using diethylamine as a catalyst. The yield obtained from microtube reactor system spans from 77% to 97% using diethylamine as a catalyst and from 56% to 84% using piperdine as a catalyst while the pressure DROP across the micromixer ranges from 0.9 to 12 kPa.