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Effect of Bottom Baffles and Air Inlet Position on Mass Transfer Performance of a Water-Sparged Aerocyclone
Facheng Qiu,
Wen Cheng,
Haifeng Wu,
Fei Xu,
Xuejun Quan,
Lu Yang
Issue:
Volume 6, Issue 4, July 2018
Pages:
44-48
Received:
20 June 2018
Accepted:
1 July 2018
Published:
25 July 2018
Abstract: Water-sparged Aerocyclone (WSA) is a new type of gas-liquid mass transfer equipment with a coupling field of liquid jet with gas cyclone, which can be widely used in wastewater treatment process. To further optimize the structural design of WSA, the effect of bottom baffles and air inlet position on mass transfer performance of WSA was comparatively studied by air stripping of ammonia from wastewater. The results indicated that the separation space configuration of a WSA affects its mass transfer performances. Under the same condition, the axial air inlet position has no effect on mass transfer performance, but moving air inlet position downward could reduce the gas pressure drop in WSA by about 10%, which was probably caused by abating the friction loss between the gas cyclone and the wall. In case of high air inlet velocity and low liquid flow rate, the bottom baffles in the WSA could intensify the mixing effect between gas and liquid phases, thereby improving the mass transfer performance, and the effect is more pronounced with the increase of air inlet velocity. The results could be used as a guide for the design of WSA with excellent mass transfer performance.
Abstract: Water-sparged Aerocyclone (WSA) is a new type of gas-liquid mass transfer equipment with a coupling field of liquid jet with gas cyclone, which can be widely used in wastewater treatment process. To further optimize the structural design of WSA, the effect of bottom baffles and air inlet position on mass transfer performance of WSA was comparativel...
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Synthesis and Characterization of Zr-Doped Vanadium Oxide Nanotubes
Azita Saliman,
Hamid Reza Aghabozorg,
Sepideh Ketabi
Issue:
Volume 6, Issue 4, July 2018
Pages:
49-53
Received:
15 May 2018
Accepted:
8 June 2018
Published:
27 July 2018
Abstract: In this research study for the firsttime zirconium doped vanadium oxide nanotubes (VONTs) were synthesized. Zr-doped VONTs were performed by using hydrothermal method. Zr-VONTs prepared 0.02 wt%. The structure and morphology of the nanotubes were investigated by x- ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In contrast to the undoped VONTs, the interlayer distance between oxide layers in the (V0.98Zr0.02 ) x ONTs increases owing to replacement of some V in nanotubes by Zr with a large ionic radius. The results showed that zirconium 0.02wt% doped VONTs complately and the doping Zr into VONTs leads to increasing interlayer distances.
Abstract: In this research study for the firsttime zirconium doped vanadium oxide nanotubes (VONTs) were synthesized. Zr-doped VONTs were performed by using hydrothermal method. Zr-VONTs prepared 0.02 wt%. The structure and morphology of the nanotubes were investigated by x- ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron ...
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Production of Fatty Acid Methyl Ester from Microalgae Using Microwave: Kinetic of Transesterification Reaction Using CaO Catalyst
Issue:
Volume 6, Issue 4, July 2018
Pages:
54-59
Received:
23 July 2018
Accepted:
7 August 2018
Published:
4 September 2018
Abstract: Biodiesel, an alternative diesel fuel made from renewable sources such as vegetable oils and animal fats, is becoming prominent among alternatives to conventional petro-diesel due to economic, environmental and social factors. Transesterification is the most preferred method of biodiesel production. Knowledge of transesterification reaction kinetic enables prediction of the extent of the chemical reaction at any time under particular conditions. It is also essential in the design of reactors for biodiesel production in industrial scale, determination of kinetic model and optimization of operation conditions. In this study, a mathematical model for the microwave assisted trans-esterification reaction of microalgae and methanol has been developed to study the effect of the operating parameters on the process kinetics. A well-mixed microwave reactor was used to express the laboratory scale microwave reactor at stirring speed 500 rpm. Mass transfer controlled state was assumed to be minimal using the stirring condition. The model developed was based on experimental data described in a previous study. The experimental works were designed to study the effect of reaction time between 1-5 min; power of microwave of 100-400 W, and an amount of CaO catalyst of 1 and 3%. The use of a solid catalyst effectively reduces the purification cost of biodiesel due to ease of separation and potential for reuse. The molar ratio of microalgae oil and methanol was constant at the ratio of 1: 6. The validation of model indicated that the reaction have second order reaction in terms of triglycerides. A very good correlation between model and experiment data was observed by correlation coefficient (R2) and least square curve fit. In addition, the experiment shows that the best conditions for reaction time were 5 min, power of microwave was 400 W and amount of CaO catalyst was 3%. The maximum yield of biodiesel in the best conditions was 93.23%.
Abstract: Biodiesel, an alternative diesel fuel made from renewable sources such as vegetable oils and animal fats, is becoming prominent among alternatives to conventional petro-diesel due to economic, environmental and social factors. Transesterification is the most preferred method of biodiesel production. Knowledge of transesterification reaction kinetic...
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The Effect of Catalyst Ratio on the Pyrolysis Yields for Waste Tyre
Falah Fahed Banihani,
Zaid Falah Bani Hani
Issue:
Volume 6, Issue 4, July 2018
Pages:
60-64
Received:
1 August 2018
Accepted:
19 August 2018
Published:
15 September 2018
Abstract: This paper focus on the thermal pyrolysis of used tyre with different catalysts at a temperature 550°C and at a heating rate of 15°C/min. The effect of process parameters on liquid yield, char formation and volatiles were also studied. In the present work, thermal pyrolysis of waste tyre samples with two selected catalysts, namely Jordan zeolite (zeolite Jo) and activated alumina was carried out in a fixed-bed reactor. The catalyst was mixed with feedstock in different percentages (10%, 15%, 25% and 35% w/w). The effects of catalysts and their ratio on the pyrolysis product oil were investigated and the results were compared with the results of experiments performed without catalyst under the same conditions (temperature 550°C at a heating rate of 150C/min). The maximum liquid yield obtained from pyrolysis of waste tyre via catalyst were found as 49.32% and 51.54% on using activated alumina and zeolite Jo as catalysts, respectively, while these values were 42.48%, without catalyst. The mass loss of tyre was examined using the thermo gravimetric analysis profiles (TGA) at heating rate of 15°C/min in air atmosphere from room temperature up to 600°C. The tyre pyrolysis liquid product has been characterized including fuel properties, proximate analysis, and ultimate analysis and FTIR. Fuel properties show that it can be used as liquid fuels.
Abstract: This paper focus on the thermal pyrolysis of used tyre with different catalysts at a temperature 550°C and at a heating rate of 15°C/min. The effect of process parameters on liquid yield, char formation and volatiles were also studied. In the present work, thermal pyrolysis of waste tyre samples with two selected catalysts, namely Jordan zeolite (z...
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Memory of Chiral Molecules Define Their Interactions and the Results of Resolution Processes
Emese Pálovics,
Elemér Fogassy
Issue:
Volume 6, Issue 4, July 2018
Pages:
65-71
Received:
15 May 2018
Accepted:
10 August 2018
Published:
21 September 2018
Abstract: The preparation of pure enantiomers has an increasing demand both for academic and industrial (pharmaceutical) practice. This is not surprising, because the active ingredients of a main part of medicines (about 70-80%) are pure enantiomers. Several selective methods are known for preparation of pure enantiomers but the more economical and usual method is the resolution, when the pure enantiomers are obtained from diastereomeric salts formed due the reaction of the racemic compound and resolving agent in adequate conditions (solvent, temperature crystallization time). Since the first resolution effectuated by Pasteur the researchers have tried to explain what is happening during resolution, but this has not yet been fully accomplished, it is still a mystery. In this paper is described our proposal for resolution’s mechanism, based on systematization of our results and observations made during the resolution, taking into consideration the principal characteristics of enantiomeric mixtures, namely the eutectic composition and their helicity. We suppose that the enantiomers have a memory and they used it during the resolution processes, tending to form their stable symmetric conformation.
Abstract: The preparation of pure enantiomers has an increasing demand both for academic and industrial (pharmaceutical) practice. This is not surprising, because the active ingredients of a main part of medicines (about 70-80%) are pure enantiomers. Several selective methods are known for preparation of pure enantiomers but the more economical and usual met...
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