1,720,983 research outputs found
A new supporting tool for pig handling in the breeding-slaughterhouse production chain
No full textThis paper focuses on a research concerning the operational management of the pig-handling phase, during the period of breeding and before slaughtering. Given the behaviour of these animals during transfers, a particular tool has been designed to manage them in this phase. A total number of 48 animals, divided in 4 groups, were moved without use of the tool (control groups) and by using the tool described in this article. The time required by the control groups to leave the pen ranges from 21 to 125 seconds; while, when the proposed tool was used, the time for the movement of the animals ranged between 10 and 17 seconds. In particular, in the groups where the tool was deployed the 'waiting phase' (before the first animal goes out) lasted less than half of the time of the 'waiting phase' of the control group, thus showing a minimization of the effects of the 'panic phenomenon' among the animals. Thus, the studied device can be considered as valid guide technique, both for the quick exit of the first animal and for those that follow. Once the row has been formed, the animals continue neatly to leave the box. This study also shows that this solution can also be considered appropriate for reducing the identified critical issues in the traditional handling. The need of only 1 worker to move the group of pigs is important to achieve economic saving. The deployment of this tool, thus, make possible to consider the movement of animals no longer a 'critical stage', but as a routine step of the production cycle of pork's meat
Experimental Evaluation of Functional and Energy Performance of Pneumatic Oenological Presses for High Quality White Wines
Full text linkIn this article, experimental tests on two different kinds of pneumatic presses have been carried out in two Apulian wineries to evaluate energy consumption related to yield performance. The presses are employed to process Bombino Nero variety grapes, crushed and transformed in rosé wine though a pomace less process. The pneumatic pressured press realized a 2 h:48 min long process, with a maximum pressure on the product of 1.4 bar and a must moulding of 69% of extracted must. In regard to the vacuum press, the process duration is 3 h:18 min, with a maximum pressure of 0.9 bar and a must moulding of 58%. During the pressing operation, mean values of must flow rate are comparable: 2.1 L min−1 m−2 for the pressured press and 2.9 L min−1 m−2 for the vacuum press. However, a more detailed analysis gives more insight on the behaviour of the two presses. In regard to the pressured press, a compression phase characterized by few steps and at lowest pressure values has proven particularly effective, especially in the first phase (must moulding of 41% with a must flow rate of 4.6 L min−1 m−2), at the lowest pressure values. On the other hand, by analysing vacuum press process, the phases sequence is much more gradual, must moulding decreases as the extraction proceeds (from 28% to 6%), and in the last three phases a very low amount of must is extracted, with must moulding smaller than 10%. The energy consumption of the pressured press during compression is mainly related to the engine power absorption (one of the two in operation), and it is below 4 kW except during start-up, due to the starting currents. The highest power is reached in the last phase in which the maximum pressure is applied and a great amount of must is extracted. On the other hand, energy consumption in the vacuum press gradually decreases. A similar trend was not observed for the specific energy for either press: while it increases along the whole process for the vacuum press, it reaches a maximum value in the second phase of the pressured one. Results show the need to pursue new studies on single component design and on pressing cycles, especially in high-capacity pneumatic vacuum presses. Several advantages on wine production costs could be achieved, even retaining high quality wines
Energy analysis and numerical evaluation of the decanter centrifuge for wastewater management to allow a sustainable energy planning of the process
Full text linkThe decanter-centrifuge is widely used for dewatering and thickening of civil and industrial sludge. The latest generation decanters, both the bowl motors (main) and the screw (back-drive) are often driven by variable-frequency drives (VFD), with the back-drive able to recover the energy during braking. We created a decanter centrifuge energy model equipped with a braking recovery system during the sludge dewatering process, with the aim of identifying its optimal operating conditions for both energy consumption and product quality. Specific models at 15–20–25 m3 h−1 and various differentials speed (Δn) were used to derive a general model, then validated with experiments at 18–20 m3 h−1. Specific models used to identify the best operating conditions in terms of specific energy (e) and energy recovery (ERec) show that at 15–20–25 m3 h−1 the lowest energy consumptions were 1.88–1.76–1.57 kWh m−3, respectively, instead, ERec was 5.88–0.31–12.10 kW respectively, highlighting that a high recovery is not necessarily linked to an increased energy saving. The accuracy of these models was confirmed by high values of correlation coefficients R2 and very low Root Mean Square Errors (RMSE) in each case. The general model, extrapolated from the specific models, makes it possible to predict specific consumptions at different flow rates within the operating range of the decanter. This was validated with an experimental test at 18–20 m3 h−1 with R2 above 97 % and RMSE 2,59E-02 kWh m3. The dry matter content in the cake decreases when the Δn or the feed rate increases.In conclusion, the decanter centrifuge model could represent a useful tool for optimizing the sludge dehydration process
A Preliminary Study to Optimize the Managing of Waste and By-Products in a Small-Scale Olive Mill
No full textOlive oil extraction process produce huge amount of by-products and waste. Furthermore, these are produced in a short period of time, not justifying the investment in expensive systems to be created for their disposal, especially in small/medium sized mills. Particularly, olive mill generates two types of waste. One is a solid waste called pomace, while the second one is wastewater. Olive oil wastes are considered highly pollutant and phytotoxic due to the presence of natural compounds like phenols. An improper disposal of wastewater on soil could results in a decreasing of water retention and infiltration rate, and could affect soil acidity and salinity. As for the pomace, this represents a by-product that can be reused as a raw material in a pomace factory. This depends greatly on the way in which the solid-liquid separation is carried out. Specifically, a three-phase decanter centrifuge produces a drier pomace than that obtained with a two-phase centrifuge. In the latter case, the pomace needs to be dried before sending it to the pomace factory. In this study, a preliminary feasibility was conducted to optimize the reuse of the by-products of a small/medium sized oil mill equipped with two extraction lines in parallel: one with a two-phase decanter, one with a three-phase decanter. The possibility of introducing a machine for concentrating the pomace leaving the two-phase process and a new line for wastewaters management has been evaluated. This relatively cheap solution would allow the entire dry pomace to be sent to a pomace factory and the wastewater, mixed to light solids, to a biogas plant as a new product identified as biphasic pomace. If the material balances are appropriately completed, this solution would make it possible to drastically reduce the waste coming out of a small/medium mill
CFD Analysis of a Tubular Heat Exchanger for the Conditioning of Olive Paste
Full text linkThe 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
Modelling the Rheology of Olive Paste for Oil Extraction Plant Automation: Effects of the Crushing Process on the Rheology of Olive Pastes
Full text linkIn extra virgin olive oil production, it is essential to obtain a well-prepared olive paste which allows not only the extraction of the oil drops from the olives, but also the achievement of a high-quality oil while maintaining high yields. This work addresses the problem of determining the effect of three crushing machines on the viscosity of the olive paste: a hammer crusher, a disk crusher and a de-stoner were tested. The tests were repeated on both the paste leaving each machine and the paste to which water was added; this was done with the main aim of considering the different dilutions of the paste while entering the decanter. A power law and the Zhang and Evans model were used to analyse the rheological behaviour of the paste. The experimental results allow validation of the two models with a high (more than 0.9) coefficient of determination between experimental and numerical data. The results also show that the pastes obtained with the two classic crushing methods (hammers and disks) are almost identical, with a packing factor of about 17.9% and 18.6%, respectively. Conversely, the paste obtained with the de-stoner entails higher viscosity values and a smaller solid packing factor, of about 2.8%. At 30% dilution with water, the volume of the solid concentration dropped to about 11.6% for the hammer and disc crushers, while for the de-stoner it only reached 1.8%. This behaviour is also reflected in the evaluation of yields, which were 6% lower with the de-stoner. No significant differences regarding the legal parameters of oil quality were found using the three different crushing systems. Finally, this paper establishes some fundamental pillars in the research for an optimal model for identifying the rheological behaviour of the paste as a function of the crusher used. Indeed, since there is an increasing need for automation in the oil extraction process, these models can be of great help in optimizing this process
Energetic analysis and optimal design of a CHP plant in a frozen food processing factory through a dynamical simulation model
No full textThe proper design of cogeneration plants requires the choice of the technologies that best fits the ratio between heating and power loads. In this paper, a dynamical procedure of selecting and dimensioning a cogeneration plant, using deep and detailed energy, exergy and economic analysis of the entire production process of a frozen food production factory is proposed. The results highlight that a design method, based on a dynamic simulation, optimizes the energy efficiency of the food processing plant involved in the experimental test. Indeed, by considering the overall efficiency of the CHP + National grid system, the energy efficiency is 6% higher in the case of dynamic compared to a static design, resulting in better overall use of resources with a possible lower level of environmental impact. Moreover, the CHP plant designed with the proposed method generates electrical energy which appropriately matches that required by the process, with a surplus/deficit less than 4%, while the classic method never covers the amount required and results in a deficit greater than 20%. Finally, the annual savings of the solution derived from the dynamic method is 12% higher than that obtained with a traditional design technique. Considering the greater absolute cost of the cogeneration plant, this dynamic approach results in more profitable annual investment margins for the company
Assessment of the olive oil extraction plant layout implementing a high-power ultrasound machine.
No full textThe objective of this study is to assess the effects of installation and operation of a high-power ultrasound machine (HPU) for the treatment of olive paste by using ultrasound technology in order to evaluate the best way installation and the best definition of the operating conditions of the machine. The study was conducted installing in an industrial olive oil mill a continuous processing ultrasound machine, which used a frequency of 20 kHz able to work at 3200 kg h-1 as feed capacity. Checking of performance has been carried out by the assessment of the different operating and process conditions, assessing in particular the impact of the ultrasound treatment before and after the malaxation phase on performance indicators of the continuous olive oil plant (plant extractability, olive paste rheological characteristic) and on selected chemical properties of the olive oil extracted (quality parameters, antioxidant content, and volatile profiles). In the tested conditions, high-power ultrasound treatment did not produce significant effect on the legal parameters (free acidity, peroxide index and spectrophotometric indexes), while a significant increase in the content of phenolic compounds was generally observed; higher enhancements were more evident when the high-power ultrasound treatment was carried out before the malaxation phase
Investigation of an Energy-saving System to Reduce the Energy Consumption of Decanter Machine
Full text linkThis 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 (Dn) 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 ab
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