Analysis of Pulsed electric field pre-treatment for beet juice extraction: Evaluation of treatment chambers configuration effects

The major challenge today for the application of PEF in the industry has interest to increase the production capacity and improve the quality of food products. PEF pre-treatment is a multifactorial process. In addition to the electric field intensity, pulses number and the capacitor value, the configuration of the treatment chamber now presents a significant parameter in this process.Cylindrical and square parallelipedic treatment chambers (TC) are compared and their effect is studied with variation of electric field, number of pulses and capacitor value at frequency of 1Hz. The results show that the cylindrical treatment chamber showed higher beet juice yield with all studied parameters. The quality of extracted juice estimated in terms of absorbance at 530 nm wavelength were determined for each sample and results show that using a cylindrical treatment chamber configuration in PFE technology  gives a  good juice quality compared with square parallelipedic treatment chamber. The energy consumption during PEF treatment is reduced in the cylindrical treatment chamber due to the low values of the electric field, pulses number and capacitor value compared with square parallelipedic treatment chamber

Comparative experimental analysis of ozone generation between surface and volume DBD generators

International audienceOzone generation by dielectric barrier discharge (DBD) is widely used in industry. Several DBD configurations can be used to generate ozone, which are classified in two main types depending on the geometry of the electrodes: volume DBD and surface DBD models. The aim of this work is to conduct a comparative experimental analysis between surface DBD and volume DBD ozone generators having a cylindrical geometry. This comparative investigation is carried out not only in terms of ozone concentration and energy efficiency, but also in terms of cooling performance. Two experimental setups were used in this work, one for measuring the ozone concentration (in mg/L) and the ozone rate production (in g/h) and a second for cooling experiments. The obtained results show that although the volume DBD model is the most frequently used in industry, the surface DBD reactor gives better results in terms of ozone rate production and cooling

DEVELOPMENT OF HIGH-VOLTAGE HIGH-FREQUENCY POWER SUPPLY FOR OZONE GENERATION

A high-voltage high-frequency power supply for ozone generation is presented in this paper. Ozone generation is intended to be used in air and in water disinfection. A power stage consisting of a single-phase full bridge inverter for regulating the output power, a current push-pull inverter (driver) and a control circuit are described and analyzed. This laboratory build power supply using a high voltage ferrite transformer and a PIC microcontroller was employed to energize a dielectric barrier discharge (DBD) ozone generator. The inverter working on the basis of control strategy is of simple structure and has a variation range of the working frequency in order to obtain the optimal frequency value. The experimental results concerning electrical characterization and water treatment using a cylindrical DBD ozone generator supplied by this power supply are given in the end

Combined ozonation process and adsorption onto bentonite natural adsorbent for the o-cresol elimination

This work studies the removal of o-cresol from wastewater by using ozonation followed by adsorption onto sodium natural bentonite (Na-Bent). The degradation of o-cresol was followed by UV-Vis. During ozonation, 2-methylbenzoquinone (2-mBQ) and 2-methylhydroquinone (2-mHQ) were identified as two of the main by-products, while the pH decrease suggested the breakage of aromatic compounds into smaller organic acids. After 30 min treatment, the o-cresol degradation for 250–62.5 mg/L solutions was found between 64–85%, respectively. Next, the wastewater containing persistent o-cresol and by-products was contacted with Na-Bent adsorbent. The solutions and physicochemical properties of Na-Bent were analysed, before and after adsorption, by UV-Vis, FTIR, XRD and N2 adsorption-desorption. Moreover, equilibrium and kinetic experiments were carried out to study the adsorptive properties of the Na-Bent. While sole ozonation or adsorption failed on the remediation of o-cresol solutions, the obtained results show that the contact of ozonated solutions with Na-Bent led to almost total removal of the o-cresol initial concentrations (between 96% and 99%). This excellent performance is assigned to the high volume of interlayer micropores and the suitable surface chemistry of this natural adsorbent.The authors would like to thank the Algerian Directorate General of Scientific Research and Technological Development (DGRSDT) and the Ministry for Higher Education and Scientific Research for the financial support for this work. In addition, the Spanish Ministerio de Economía y Competitividad and FEDER funds (RYC-2017-23618) are gratefully appreciated