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Ultrasound reactor - The solution for a continuous olive oil extraction process

Periodic Reporting for period 3 - OLIVE-SOUND (Ultrasound reactor - The solution for a continuous olive oil extraction process)

Période du rapport: 2021-01-01 au 2021-12-31

European Union is worldwide leader of virgin olive oil extraction (around 67% of overall production), with around 9000 olive oil mills; this is a mechanical process split in 3 main phases: crushing, malaxation and separation. Both crushing and separation are continuous processes while malaxation is a batch-sized process becoming the “bottleneck” of the entire plant; it is usually solved adding more malaxers in parallel negatively affecting costs.
Olive-Sound project proposes a cost-effective and innovative solution to this point converting the traditional slow and inefficient malaxation into a continuous process by application of ultra-sound without compromising the quality of the product. US enhances extraction efficiency and extraction rate, resulting in increased yields, content of phenolic compounds and improves the sensory, nutritional characteristics and shelf-life of the VOO with following expected advantages:
- Reduction of process time by 70%
- Energy conservation positively impacting the environment
- Cost-effectiveness
- Improved VOO quality
- Compliance with EU regulation
- Modulation of the process
The project has been thought to process olive oil paste with US. This technology, used in an oil mill plant, allows to combine the better and fast extractive capacity of oil from the olive fruit with a higher quality of the final product VOO. This new approach can increase the content in polyphenolic substances minimizing thermal and oxidative damage. The US treatment of olive paste is a radical innovation since it is the only process that has allowed the extraction of more oil, with a higher polyphenolic content than the known techniques, at plant costs that could lead to a pay-back already during the first campaign thanks to higher quantities of oil with higher commercial value.
The steps identified to achieve TRL9 are:
- Manufacture an improved version of the latest prototype with the final shape
- Optimize distribution and configuration of transducers via fluid dynamics and vibro-acoustic modelling
- Validate the system efficiency and the quality of produced olive oil at pilot scale
- Manufacture the scaled-up version
- Launch Olive-Sound into the market
The goal of the consortium is to bring to the market a commercial product taking care in the best way of dissemination and exploitations activities.
The project lays the foundations on the innovative idea of applying US technology to the oil sector, an idea developed by UNIBA starting from laboratory experiments with a TRL3 and developing an industrial scale up that allowed the project partnership to transfer the know-how necessary to reach TRL9 in this project. For the end of the project, the 1000 kg/h small scaled-up prototype was completely assembled and shipped to Ctic Cita where it was tested with different type olives and different maturity indexes, at different power levels (25%, 50%, 75% and 100%). In parallel, Cedrat and Pieralisi defined the design of the full-scale prototype with the main goal to reach the production flow rate of 4000kg/h based on a concept of 4 identical machines very similar to the one tested at Ctic Cita facilities.
The second period should have been dedicated to the development and construction of the full-scale machine arriving to the nominal 4000kg/h flowrate, but due the international emergency related to COVID-19, some activities were lagging behind the original planning in terms of timing. Therefore, an extension of the project duration was requested. Taking advantage of the extension, the scaled-up prototype was also tested during the 2020-2021 campaign adding the combination of the thermal effect to consolidate results that prove the correct operation of the machine in terms of yield, free fatty acids, peroxide values, K232, K270, polyphenols, volatile compounds, etc. The tests were very important to mill GREEN OLIVES, so they were done before the green olives season’s end in an olive oil mill based in Apulia, Italy. In parallel, a continuous monitoring of the olive oil market and the olive mills market was performed. All the results obtained up to this moment were used by Cedrat and Pieralisi for the development of the final industrial equipment.
In the third period, OLIVE-SOUND 4x reactor was assembled in Pieralisi facilities and then sent to Almazara Del Ebro olive mill for the installation. The scaled industrial machine was tested with different kind of olives as planned: Arbequina, Empeltre and Picual olive cultivars. Ctic Cita carried out the sampling during the different tests in the three stages of maturation that were processed. The results were analysed by physico-chemical and sensory analysis where it was confirmed that the use of US allows obtaining similar yields to traditional processing without affecting the quality of the product (all the oils complied with the standards established by the UE) and reducing the processing time.
OLIVE-SOUND machine was presented to the “XX Simposium Científico-Técnico” that took place at Expoliva, one of the most important olive oil global event. A webinar took place between partners and possible future customers of OLIVE-SOUND reactor.
The development of US dedicated to olive oil is improving the state of art of this technology up to 24kW. From a wider market perspective, the technology dedicated to olive oil milling is moving slowly so that this technology should arrive to the market as expected from the initial plan.
This project allows to transform the bottleneck within the VOO extraction process (malaxing) into a continuous process, reducing process time by 70%.
Tests performed during the second period confirmed the results obtained with the first prototype. The machine was tested at its nominal flowrate obtaining a continuous process of extraction. The high-quality oil extracted shown that the application of this technology to the extraction process can also maintain the product quality and yield working at lower temperatures compared to traditional process. This will allow customers to save energy and obtain a higher product quality. Validation on an industrial scale confirmed that it was possible to process the olives at the different stages of maturity, although an advantage it was only detected in the processing of olives with the lowest maturity index. This type of olives was the only one where the yield was similar to the traditional control.
This important innovation hugely reduces the processing time thanks to the US technology, but in any case, it does not completely replace the use of the malaxers. The phase of paste mixing is still too much important to obtain high level of quality and yield. This mixing phase is reduced a lot, solving then the bottleneck within the VOO extraction process but at the moment this requirement increases the cost of the industrial plant. More studies must be performed to achieve the optimal and the more efficient way to extract olive oil, transforming that in a real continuous process.