Parametric study via full factorial design for glycerol supercritical gasification

International audienceSupercritical water gasification is a promising technology for pollution treatment and syngas pro- duction from biomass. The produced gas is composed of hydrogen, carbon dioxide, methane, car- bon monoxide and traces of ethane and other light hydrocarbons. This work aims to give a comprehensive experimental study of the supercritical water gasification of glycerol using a full factorial design of experiments (DOE). The effect of five factors, namely: temperature [458°C–542°C], residence time [40–90min], pressure [23–27MPa], initial concentration of glycerol [10–19wt%] and KOH catalyst quantity [0.60–1.475wt%], were investigated on several responses such as the gasification efficiency (GE), syngas composition and lower calorific value (LCV) of the produced gas. First order mathematical models correlating each considered response in terms of the considered factors were developed and validated. Also, the significance of the factors effect was validated using analysis of variance. The results showed that the produced gas composition and quality were strongly influenced by temperature and initial concentration. The largest gas pro- duction was detected at a temperature of 542°C, a residence time of 40min, a pressure of 27MPa, a concentration of 10 wt% glycerol and a KOH catalyst percentage of 1.475 wt%

Optimization of formulation for surrogate fuels for diesel–biodiesel mixtures

Alternative or surrogate fuel is a carburant made up of a reduced number of constituents that emulate the characteristics and performance of a target fuel which may contain more than a thousand compounds. In order to overcome the composition complexity and permit the simulation of kinetic models, an optimization of the surrogate fuel composition is necessary to reproduce physical and chemical properties of a target fuel. The main objective of the present research is to optimize a formulation for an alternative fuel that emulates a target fossil diesel (B0), and an obtained biodiesel (B100) from a transesterification of cooking vegetable oil. To enhance the application of biodiesel as an alternative solution to depleting fossil fuel, mixtures of diesel and several percentages of biofuel are also considered as target fuels, considering 5%, 10%, 20%, 50% and 80% of biodiesel, denoted respectively: B5, B10, B20, B50 and B80. The target properties considered in this work are the density at 15 °C, the viscosity at 40 °C and the cetane number using a palette of 18 components selected from previous works. The numerical method of the Generalized Reduced Gradient (GRG) is used to optimize the defined objective function. The results obtained showed that the optimized surrogates for fossil diesel, biodiesel and their blending agree well with target properties and all the optimized alternatives are composed of only the same three constituents, namely: 1-methylnaphthalene, isocetane and n-eicosane

Optimization of formulation for surrogate fuels for diesel–biodiesel mixtures

Alternative or surrogate fuel is a carburant made up of a reduced number of constituents that emulate the characteristics and performance of a target fuel which may contain more than a thousand compounds. In order to overcome the composition complexity and permit the simulation of kinetic models, an optimization of the surrogate fuel composition is necessary to reproduce physical and chemical properties of a target fuel. The main objective of the present research is to optimize a formulation for an alternative fuel that emulates a target fossil diesel (B0), and an obtained biodiesel (B100) from a transesterification of cooking vegetable oil. To enhance the application of biodiesel as an alternative solution to depleting fossil fuel, mixtures of diesel and several percentages of biofuel are also considered as target fuels, considering 5%, 10%, 20%, 50% and 80% of biodiesel, denoted respectively: B5, B10, B20, B50 and B80. The target properties considered in this work are the density at 15 °C, the viscosity at 40 °C and the cetane number using a palette of 18 components selected from previous works. The numerical method of the Generalized Reduced Gradient (GRG) is used to optimize the defined objective function. The results obtained showed that the optimized surrogates for fossil diesel, biodiesel and their blending agree well with target properties and all the optimized alternatives are composed of only the same three constituents, namely: 1-methylnaphthalene, isocetane and n-eicosane

p-T-x Measurements for 1,1,1,2-Tetrafluoroethane (R134a) + N,N –dimethylacetamide (DMA), and N-methyl-2-pyrrolidone (NMP)

International audienceThe present study concerns p-T-x phase equilibria measurements involving two working fluid pairs (Refrigerant + Organic solvent) , namely 1,1,1,2-tetrafluoroethane (R134a) + N,N – dimethylacetamide (DMA) and , 1,1,1,2-tetrafluoroethane + N-methyl-2-pyrrolidone (NMP), using the static-analytic method at temperatures varying between 303 and 353 K. The experimentally measured data were successfully correlated using the Peng – Robinson equation of state (PR-EoS) in combination with Huron-Vidal mixing rule, and the non-random two liquid activity coefficient model (NRTL), contrarily to the predictive Soave-Redlich-Kwong (PSRK) group contribution equation of state which failed to reproduce accurately enough such data

p-T-x Measurements for Some Working Fluids for an Absorption Heat Transformer: 1,1,1,2-Tetrafluoroethane (R134a) + Dimethylether Diethylene Glycol (DMEDEG) and Dimethylether Triethylene Glycol (DMETrEG)

International audienceThe solubilities of 1,1,1,2-tetrafluoroethane (R134a), CF3CH2F, + dimethylether diethylene glycol (DMEDEG), CH3O(CH2CH2O)2CH3, and R134a + dimethylether triethylene glycol (DMETrEG) binary systems were measured, using the “static-analytic” method at temperatures between (303 and 353) K. This work was an opportunity to test the use of R134a as a refrigerant in combination with an organic absorbent, like DMEDEG and DMETrEG, in an absorption heat transformer (AHT), also known as a type II absorption heat pump or a reversed absorption heat pump. The experimental data were correlated using the Peng-Robinson equation of state (PR-EoS) in combination with Mathias-Copeman R function, Huron-Vidal mixing rules, and the nonrandom two-liquid (NRTL) activity coefficient model. The experimental results were compared to the predicted values obtained using the predictive Soave-Redlich-Kwong group contribution equation of state (PSRK-EoS)

Liquid–liquid equilibrium of (water + 1-propanol + 1-pentanol) system at 298.15 and 323.15 K

International audienceLiquid–liquid equilibrium data for the ternary system water + 1-propanol + 1-pentanol have been deter- mined experimentally at 298.15 and 323.15K using “static–analytic” apparatus involving ROLSITM samplers. The experimental data are correlated considering both NRTL and UNIQUAC activity coeffi- cient models. The results obtained show the ability of both models for the determination of liquid–liquid equilibrium data of the studied system. The reliability of the experimental tie-line data is determined through the Othmer–Tobias and Bachman equations

Encapsulation of Essential Oils via Nanoprecipitation Process: Overview, Progress, Challenges and Prospects

Essential oils are of paramount importance in pharmaceutical, cosmetic, agricultural, and food areas thanks to their crucial properties. However, stability and bioactivity determine the effectiveness of essential oils. Polymeric nanoencapsulation is a well-established approach for the preservation of essential oils. It offers a plethora of benefits, including improved water solubility, effective protection against degradation, prevention of volatile components evaporation and controlled and targeted release. Among the several techniques used for the design of polymeric nanoparticles, nanoprecipitation has attracted great attention. This review focuses on the most outstanding contributions of nanotechnology in essential oils encapsulation via nanoprecipitation method. We emphasize the chemical composition of essential oils, the principle of polymeric nanoparticle preparation, the physicochemical properties of essential oils loaded nanoparticles and their current applications