New approach for the elucidation of the phenomena involved in the operation of vegetable oil extraction presses

Abstract

In a context where the search for naturalness, the need to reduce the carbon footprint and the development of a decentralized crushing sector are intensifying, mechanical extraction is a technology that is regaining major importance for the industry. The performance of this technique remains far below what is desirable, while the understanding of the main phenomena involved in screw presses remains insufficient. This article, after a brief presentation of the state of the art of this discipline, presents a new model centered on the notions of pressure generation and plasticity. According to this approach, plasticity can account for parameters such as the water and oil content of oilseeds, their temperature, and their possible dehulling. Plasticity in turn would explain both the compressibility of the cake and its ability to resist the thrust of the screws, and consequently to generate pressure or to creep or flow backward depending on the geometry of the screw and the cage. The model must also incorporate the notions of compression velocity, friction, and the complexity of the interactions between these parameters and the impact of the succession of screw segments and cone rings. It has been built on observation and experience and gives an understanding of the need to work simultaneously on the conditioning and geometry of the presses to achieve improved performance in terms of energy, efficiency, and reduction of the temperatures experienced by the proteins and oils

Untitled

“…The physical essence of the improvement made for the EK-75/1200 twin-screw extrusion press is confirmed and partially described when optimising the geometry of the screw shaft of the single-screw press reflected in the study (Carré, 2022). Namely, it indicates the generally accepted statements that high pressure is needed for maximum oil production.…”

Untitled

“…5). In most of the papers with experimental studies (Evon et al, 2016;Carré, 2022), the oil pressing process was carried out under different operating conditions to evaluate their impact on oil yield, press capacity, energy consumption, etc. In S.M.…”

Leading Edge Technologies and Perspectives in Industrial Oilseed Extraction

“…There are several purely mechanical extraction methods: cold pressing, pressing after cooking and double pressing (cold pressing followed by heat conditioning and a second pressing). Their performance in terms of residual oil content in the meal ranges from 9.9 to 16.3%, 9.7 to 15.7% and 8.7 to 13.5% residual oil (rapeseed), respectively [ 36 ]. The key to the press performance is the conversion of electrical energy into pressure rather than heat.…”

“…Savoire et al [ 38 ] reported on the capacity, energy consumption and extraction efficiency of several commercially available industrial presses. The largest capacity solvent-free crushing units in the world process more than 250,000 tonnes but are mainly related to biodiesel production [ 36 ]. For these reasons, the new requirements for screw presses favour a higher capacity, lower horsepower consumption and easier maintenance.…”

“…The International Maritime Solid Bulk Cargoes (IMSBC) code classifies five types of cakes with specific loading and carriage requirements, depending on their oil and moisture content and method of extraction [ 40 ]. Press cakes are generally more hazardous than solvent-extracted meals because they have a higher residual oil content and a moisture content of between 7.3 and 11.9% [ 36 ].…”