CFD Analysis of a Tubular Heat Exchanger for the Conditioning of Olive Paste

The use of a heat exchanger for the conditioning of the olive paste could enhance the olive oil extraction process. Particularly, paste pre-heating could reduce the malaxation time and, most of all, improve the temperature control during this process (e.g., 27 ◦C). In this study, a three-dimensional computational fluid dynamics (CFD) analysis of a tubular heat exchanger was carried out to better understand the influence of the inlet conditions of the olive paste on thermal and hydrodynamic behavior within it. CFD analysis was performed with SOLIDWORKS Flow Simulation (ver.2016). The heat exchanger consists of a tube-in-tube module, in which the inner tube was fed with the olive paste, while the jacket was filled of hot water. The main aim was that to predict the heat transfer and pressure drop in paste side of the exchanger. Multiple analyses by varying the mass flow rate and inlet temperature of the paste were carried out, and temperature and pressure drop were estimated. The numerical model has proved very useful in identifying the main factors affecting the optimization of the heat exchanger in order to improve the extraction process of the olive paste

Low-frequency, high-power ultrasound treatment at different pressures for olive paste: Effects on olive oil yield and quality.

Abstract Ultrasound technology was employed to test its action on the extraction of olive oil at the industrial scale. Because of its mechanical effects, ultrasound waves were applied to the olive paste, between the crushing and malaxing operations. Comparative experiments were performed between traditional extraction processes and the innovative extraction process, with the addition of the ultrasound treatment. Different levels of pressure were tested on olive paste, using four different olive cultivars. Pressure level played an important role in olive oil extractability. When ultrasound was subjected to olive paste with a pressure of about 3.5 bar, there was a significant increase of extractability compared to the traditional process. On the other hand, there was no significant effect between ultrasound treatment and traditional technology on extractability when ultrasound at a pressure level of 1.7 bar was used

Innovation in olive oil processing plants to produce an excellent olive oil and to reduce environmental impact

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Evaluation of a multisensorial system for a rapid preliminary screening of the olive oil chemical compounds in an industrial process

In this study, a sensory system, named BIONOTE, based on gas and liquid analyses was used to analyse the headspace of olive oil samples obtained at the end of the extraction process for a preliminary screening of the volatile and phenolic compounds. Olive oil samples were obtained using different olive paste conditioning systems, including microwave and megasound machines at different processing time. The same olives batch was used for the entire test. BIONOTE showed the ability to discriminate between 64 virgin olive oils originated from different technologies or by using different process parameters, as demonstrated by the partial least square discriminant analysis (PLS-DA) models calculated. The percentage of correct classification in different conditions are in a range from 92.19% to 100%. In addition, the research shown that the multisensorial system can provide a preliminary estimation of some volatile and phenolic compounds concentrations detected by laboratory analysis. Data analysis has been performed using multivariate data analysis techniques: PLS-DA cross validation via leave one out criterion. Future perspectives are to further develop BIONOTE in order to increase the number of detected chemical compounds and finally to include the mathematical models obtained in the BIONOTE microcontroller for a rapid chemical characterization of olive oil in the mill

Investigation of an Energy-saving System to Reduce the Energy Consumption of Decanter Machine

This study presents a practical and simple approach to investigate the energy consumption of a decanter centrifuge during the sludge dewatering process. An experimental plan to measure the energy consumption of the decanter fed with sludge at three different flow rates and different differential speed values between bowl and screw (?n) was carried out. The trend of the energy withdrawn from power supply as a function of the energy consumed by the bowl motor and the trend of the energy drawn from bowl motor as a function of that recovered from the regenerative braking system has been identified. Finally, the consumption of the bowl motor and of the energy taken from the mains as a function of the flow rate has been determined. The results show that the energy drawn from the grid and the energy regenerated by the regenerative braking system is linearly correlated with the energy consumed by the main electric motor and with the sludge feed rate. In addition, as the flow rate increases, the power recovered is about ¼ of that consumed. A high correlation of the developed models has been detected. The models developed can be used to provide valuable information about energy use patterns and can be used to identify areas where energy efficiency measures can be implemented

Development of a Simplified System for the Continuous PEF Treatment of Olives Paste

The olive oil extraction is a complex process that requires several machines arranged in series until the plant is built. Currently, the extraction process does not allow the totality of the oil present in the olives to be extracted, unfortunately a significant amount of the product is lost in the by-products and waste. Recently the pulsed electric fields (PEF) applied to the process have given positive effects by increasing the percentage of oil extracted compared to the traditional plant configuration. In order to allow a greater diffusion of this technology in the mill, a simplified PEF plant it has been developed specifically for small oil extraction plants and an experimental test program has been developed to verify the effectiveness of the technology. A comparative experimental tests plant was carried out using two different varieties of olives (Frantoio and Leccino) treated at two different specific energies (4.0 and 5.0 kJ kg-1), the amount of olive oil lost in the pomace and extractability was found. The results showed that the treatment of the olive pastes in the pre-malaxation (5.0 kJ kg-1) led to significantly increased oil extractability compared to the control by about 4% (absolute value) for the Frantoio variety, and by about 3 % (absolute value) for the Leccino variety, while reducing the percentage of oil lost in the pomace. Further studies on the better adjustment of the operating parameters of the PEF system seem to be needed

Use of a Microwave Pilot Plant for Almond Disinfestation: Study on the Thermal Uniformity of the Treatment and Effect on Volatile Composition

This paper outlines the experimental application of a continuous microwave-assisted (MW) industrial pilot plant for a post-harvest treatment on almond as disinfestation. The analysis of temperature uniformity and of the volatile profile on the unshelled almonds after the physical treatment were also investigated. The major problem during the production, storage and marketing of almonds is the contamination with insects or pests. Microwaves technologies is an alternative procedure to chemical one nowadays applied. The pilot plant has a treatment chamber with five generators of 1,5 kW/each installed along. A PLC operates on Electrical Power and flow rate to configure the operative parameter for the treatment condition. Samples of unshelled almonds from homogeneous batches have been treated with MW at different conditions. Insect mortality in three different life stages: 24-hours old eggs, 24-hours old larvae and mature larvae was evaluated after MW treatments. The uniformity of heating was studied as well as a volatile profile by SPME/GC/MS after the treatment. The results show that the optimal disinfestation effects on eggs and larvae are obtained by subjecting the almonds to a MW treatment at 25-rpm as spiral rotation speed equal to a 55.7 °C as temperature of the almond. The temperatures reached, during the treatment and the related time, were not sufficient for the development of oxidative aldehydes, secondary products of the lipid oxidation. An increase in volatile compounds, important for the characteristic almond flavour such as benzhaldeyde and 3-methylbutanol, has been observed

Hyperspectral imaging system to on-line monitoring the soy flour content in a functional pasta

Pasta enriched with soy flour can be considered as a functional food, due to its content in nutraceutical compounds such as isoflavones, carotenoids, and other antioxidants. The quantification of the amount of a functional ingredient is an important step in food authenticity. The availability of non-destructive techniques for quantitative and qualitative analyses of food is therefore desirable. This research was aimed to investigate the feasibility of hyperspectral imaging in reflectance mode for the evaluation of the soy flour content, also to investigate on the possibility to implement a feed-back control system to precisely dose the soy flour during the industrial production of pasta. Samples of pasta in shape of spaghetti were produced with durum wheat semolina and soy flour at increasing percentages (0, to 50%, steps of 5%). A feature selection algorithm was used to predict the amount of soy flour. The most influent wavelengths were selected, and a six-term Gauss function was trained, validated, and tested. The identified transfer function was able to predict the percentage of soy flour with high accuracy, with an R2adj value of 0.98 and RMSE 1.31. The developed system could represent a feasible tool to control the process in a continuous mode