scholarly journals Purification of Biodiesel Produced by Lipase Catalysed Transesterification by Two-Phase Systems Based on Deep Eutectic Solvents in a Microextractor: Selection of Solvents and Process Optimization

2021 ◽  
Vol 4 (1) ◽  
pp. 25
Author(s):  
Sara Anđelović ◽  
Marko Božinović ◽  
Željka Ćurić ◽  
Martin Gojun ◽  
Kristina Zagajski Kučan ◽  
...  
Keyword(s):  
Deep Eutectic Solvents ◽  
Efficient Solutions ◽  
Process Conditions ◽  
Optimal Process ◽  
Two Phase ◽  
Chemical Catalysis ◽  
Biodiesel Synthesis ◽  
The One ◽  
Astm D6751 ◽  
Biodiesel Purification

The most important and the most used process of biodiesel synthesis is transesterification. The main byproduct formed in the biodiesel synthesis by transesterification is glycerol. Biodiesel produced by transesterification is not suitable for application in engines since it contains soap (if biodiesel is produced by chemical catalysis), traces of the catalyst, methanol, metals, water, oil, and glycerides. All those impurities must be removed in order to reach the standards (ASTM D6751 and EN 14214). The most dominant industrial method for biodiesel purification is wet washing, which generates up to 10 L of wastewater per 1 L of purified biodiesel. Therefore, cheaper and more efficient solutions for biodiesel purification should be found. Deep eutectic solvents (DESs) have been already demonstrated as viable options in biodiesel purification. DESs, a mixture of two or more components with a lower melting point than each individual component, are considered less toxic to the environment, non-volatile, biodegradable, and more stable; in other words, they are economically and environmentally friendly in comparison with organic solvents. In this study, purification of biodiesel produced by lipase catalysed transesterification by DESs was performed by two-phase liquid extraction in a microextractor. A total of 13 different DESs were synthesized and used for biodiesel purification in order to find the one that provides the best glycerol extraction efficiency. After initial screening, three DESs were selected and used for the optimization of process conditions for extraction performed in a microsystem. A three-level-four-factor Box–Behnken experimental design was employed to define the optimal process conditions (biodiesel–DES mass ratio, temperature, residence time). At optimal process conditions, the glycerol content in biodiesel was reduced below 0.02% (w/w), which is the value specified by standards (ASTM D6751 and EN 14214).

scholarly journals Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe

2008 ◽  
Vol 10 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Roch Plewik ◽  
Piotr Synowiec ◽  
Janusz Wójcik
Keyword(s):  
Cfd Simulation ◽  
Fluidised Bed ◽  
Cfd Simulations ◽  
Two Phase ◽  
Hydraulic Behaviour ◽  
Hydraulic Conditions ◽  
The One ◽  
Cfd Method ◽  
Multi Phase ◽  
The Ideal

Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe The hydrodynamics in fluidized-bed crystallizers is studied by CFD method. The simulations were performed by a commercial packet of computational fluid dynamics Fluent 6.x. For the one-phase modelling (15), a standard k-ε model was applied. In the case of the two-phase flows the Eulerian multi-phase model with a standard k-ε method, aided by the k-ε dispersed model for viscosity, has been used respectively. The collected data put a new light on the suspension flow behaviour in the annular zone of the fluidised bed crystallizer. From the presented here CFD simulations, it clearly issues that the real hydraulic conditions in the fluidised bed crystallizers are far from the ideal ones.

scholarly journals On the Two-phase Fractional Stefan Problem

2020 ◽  
Vol 20 (2) ◽  
pp. 437-458 ◽  
Author(s):  
Félix del Teso ◽  
Jørgen Endal ◽  
Juan Luis Vázquez
Keyword(s):  
Free Boundary ◽  
Stefan Problem ◽  
Free Boundary Problems ◽  
Classical Problem ◽  
Nonlocal Diffusion ◽  
Two Phase ◽  
Boundary Problems ◽  
Numerical Studies ◽  
The One ◽  
Evolution Type

AbstractThe classical Stefan problem is one of the most studied free boundary problems of evolution type. Recently, there has been interest in treating the corresponding free boundary problem with nonlocal diffusion. We start the paper by reviewing the main properties of the classical problem that are of interest to us. Then we introduce the fractional Stefan problem and develop the basic theory. After that we center our attention on selfsimilar solutions, their properties and consequences. We first discuss the results of the one-phase fractional Stefan problem, which have recently been studied by the authors. Finally, we address the theory of the two-phase fractional Stefan problem, which contains the main original contributions of this paper. Rigorous numerical studies support our results and claims.

Study of CFD Modeling of Performance for Classification

2012 ◽  
Vol 516-517 ◽  
pp. 784-789
Author(s):  
Wei Cao ◽  
Ying Fang ◽  
De Xiang Li
Keyword(s):  
Simulation Experiment ◽  
Particle Trajectory ◽  
Phase Particle ◽  
Theoretical Perspective ◽  
Cfd Modeling ◽  
Optimized Design ◽  
Two Phase ◽  
Ansys Cfx ◽  
The One ◽  
Classification Efficiency

The numerical simulation in the classification has been used in ANSYS CFX 10.0. We described the different flow fields within the classification in accordance with the one-phase simulation experiment, which provided a new theoretical perspective for optimized design on classification. At the same time, the classification efficiency was predicted by simulation for two phase particle trajectory. This will lay a foundation for improving classification efficiency.

Study on Extracting Potassium from Potassium Feldspar with Molten Salt Leaching Method

2012 ◽  
Vol 524-527 ◽  
pp. 1078-1081
Author(s):  
Jian Guo Song ◽  
Xin Zhi Wang ◽  
Shao Dan Xiao ◽  
Wei Liu
Keyword(s):  
Reaction Time ◽  
Molten Salt ◽  
Potassium Feldspar ◽  
Process Conditions ◽  
Temperature Reaction ◽  
Optimal Process ◽  
Potash Feldspar ◽  
Salt Leaching ◽  
Effects Of Temperature

This article aims to study the technology of extracting potassium from potassium feldspar with molten salt leaching method and to analyze the effects of temperature, reaction time and other factors on extracting potassium, concluding the optimal process conditions of extracting potassium with molten leaching method from potash feldspar.

scholarly journals Degradation of Landfill Leachate Using UV-TiO2 Photocatalysis Combination with Aged Waste Reactors

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 946
Author(s):  
Chunlian Wang ◽  
Xiaojie Sun ◽  
Huijun Shan ◽  
Hongxia Zhang ◽  
Beidou Xi
Keyword(s):  
Tio2 Nanoparticles ◽  
Landfill Leachate ◽  
Control Method ◽  
Irradiation Time ◽  
Combined Treatment ◽  
Oxygen Demand ◽  
Infrared Spectrometry ◽  
Process Conditions ◽  
Optimal Process ◽  
Removal Rates

This study explored the performance of TiO2 nanoparticles in combination with aged waste reactors to treat landfill leachate. The optimum conditions for synthesis of TiO2 were determined by a series of characterizations and removal rates of methyl orange. The effect of the ultraviolet irradiation time, amount of the catalyst, and pH on the removal efficiency for the chemical oxygen demand (COD) and color in the leachate was explored to determine the optimal process conditions, which were 500 min, 4 g/L and 8.88, respectively. The removal rates for COD and chroma under three optimal conditions were obtained by the single factor control method: 89% and 70%; 95.56% and 70%; and 85% and 87.5%, respectively. Under optimal process conditions, the overall average removal rates for ammonium nitrogen (NH4+–N) and COD in the leachate for the combination of TiO2 nanoparticles and an aged waste reactor were 98.8% and 32.5%, respectively, and the nitrate (NO3−–N) and nitrite nitrogen (NO2–N) concentrations were maintained at 7–9 and 0.01–0.017 mg/L, respectively. TiO2 nanoparticles before and after the photocatalytic reaction were characterized by emission scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and Fourier transform infrared spectrometry. In addition, TiO2 nanoparticles have excellent recyclability, showing the potential of the photocatalytic/biological combined treatment of landfill leachate. This simulation of photocatalysis-landfilling could be a baseline study for the implementation of technology at the pilot scale.

scholarly journals Gallstone ileus resulting in strong intestinal obstruction

1995 ◽  
Vol 113 (1) ◽  
pp. 721-725
Author(s):  
Israel Szajnbok ◽  
Fernando Lorenzi ◽  
Aldo Junqueira Rodrigues Jr. ◽  
Luis Fernando Correa Zantut ◽  
Renato Sérgio Poggetti ◽  
...  
Keyword(s):  
Intestinal Obstruction ◽  
Gallstone Ileus ◽  
Ileocecal Valve ◽  
Mortality Rates ◽  
Degenerative Diseases ◽  
Two Phase ◽  
Therapy Decision ◽  
Biliary Calculus ◽  
The One ◽  
Elder People

Mechanic intestinal obstruction, caused by the passage of biliary calculus from vesicle to intestine, through fistulization, although not frequent, deserve study due to the morbi-mortality rates. Incidence in elder people explains the association with chronic degenerative diseases, increasing complexity in terms of therapy decision. Literature discusses the need and opportunity for the one or two-phase surgical attack of the cholecystenteric fistule, in front of the resolution on the obstructive urgency and makes reference to Gallstone Ileus as an exception for strong intestinal obstruction. The more frequent intestinal obstruction observed is when it occurs a Gallstone Ileus impacting in terms of ileocecal valve. The authors submit a Gallstone Ileus manifestation as causing strong intestinal obstruction, discussing aspects regarding diagnostic and treatment.

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