Full pressing

With over 80 years of experience, Desmet deliver comprehensive pressing solutions designed to maximize oil extraction from oilseeds and nuts, while preserving protein quality. At the heart of the process is the renowned Sterling Series screw press, a proven technology from RoseDowns who have more than 200 years of experience delivering reliable extraction equipment. Desmet offers fully integrated technology packages, tailored to meet industry-specific needs, whether for cold or hot pressing, with options for cookers, extruders, and single or double-stage setups.

Press

How does it work?

The key to an effective separation process in oils is proper mechanical, and sometimes thermal, preparation before screw-pressing. After separation, oils and the solid protein-containing cake must be processed carefully to preserve their nutritional or technical value. Desmet masters all aspects of preparation, screw-pressing, and further processing, offering customised solutions for each full press application.

The oilseed full pressing process may include the following steps:

  • Seed conditioning: adjusting moisture and temperature for optimal processing
  • Cracking: reducing seed particle size
  • Seed dehulling: removing shell to increase protein content in the de-oiled cake
  • Flaking: rupturing the cell structure of broken seeds
  • Cooking: reducing oil viscosity and adjusting moisture for improved press performance
  • Dry extrusion: an alternative to cooking and flaking
  • Pre-pressing: recovering easily extractable oil in multi-stage pressing
  • Full pressing: recovering maximum oil
  • Oil clarification: removing suspended solids from crude oil
  • Cake cooling: reducing cake temperature before storage

Full pressing can be done with either ambient or heated feed materials, leading to two process variants: cold pressing and hot pressing.

Cold pressing

Cold pressing is recommended for the highest quality oils whilst preserving the cake's protein quality. The feed material should enter the press at ambient temperature, though pre-conditioning may be required in colder climates to adjust temperature and moisture levels.

To maintain temperatures between 60°C and 70°C in the press cage, and maximize oil recovery while preserving protein, the screw shaft operates at a lower speed. Crude oil and suspended solids (foots) are separated during oil clarification, and the de-oiled cake is cooled before storage.

Due to the relatively low process temperature, the moisture in cold-pressed oil may be too high for storage and may require drying before clarification. Cold-pressed oil generally has fewer gums, and a lighter color compared to hot-pressed oil, making it suitable for physical refining or direct bottling in some cases. The cold-pressed cake retains high protein quality, making it ideal for specific food applications like protein isolates.

Advantages of cold pressing

Protein quality

The limited temperature rise in the press cage ensures that the cake's protein remains unaffected by the process.

Oil quality

Cold-pressed oil can command a premium value in the market.

Hot pressing

Hot pressing is recommended when the focus is on maximizing oil yield and increasing cake protein concentration. The feed material typically enters the press at 105 – 120°C with 2-4% moisture. To achieve these conditions properly prepared oilseeds are heated in a cooker by indirect steam contact and dried using counter-current airflow.

Friction on the cooked seeds inside the press cage allows for a high oil extraction rate, leaving the cake with 7 to 10% residual oil at the outlet.

Due to the high process temperature, moisture in the oil evaporates. After decanting, where most suspended solids are removed, the oil is filtered and cooled before storage. The hot press cake, discharged at around 120°C, is cooled using counter-current airflow before storage.

Advantages of hot pressing

Oil yield

Hot pressing achieves a higher oil extraction rate, making it ideal when oil is the main product.

CAPEX

Mechanical extraction is simpler than solvent extraction, making full pressing suitable for projects with lower CAPEX and shorter lead times.

Flexibility

Hot full pressing is easily customizable for multi-seed processing projects.

Raw materials

Desmet's full pressing solutions are designed to handle a wide range of raw materials, including rapeseed, sunflower, soybeans, linseed, mustard seed, ground nuts, shea nuts, and cocoa beans for efficient oil extraction.

Other

Cocoa beans

Cocoa beans

Rapeseed

Rapeseed

Shea nuts

Shea nuts

Soybeans

Soybeans

Sunflower

Sunflower

Key proprietary equipment

The full pressing process relies on advanced equipment, including conditioners, presses, and vertical cookers, specially designed to optimize seed preparation, enhance oil extraction, and ensure maximum efficiency in feed production.

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Conditioners

Our seed conditioning equipment is designed to optimize CAPEX and OPEX, delivering reliable performance under the most severe conditions.

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Sterling Series presses

The innovative design reflects years of RoseDowns industry expertise. With the Sterling Series offering exceptional pre-press and full press performance across various throughputs.

Vertical Cooker

Vertical Cookers

The vertical cooker provides heat transfer and airflow drying at same time, while occupying minimum footprint. It also provides buffer volume allowing recycling of foots or pressed materials during start up.

Our services

With a focus on cutting-edge technology, high-quality components, and comprehensive on-site support, our service teams ensure optimized plant performance and minimized operational disruptions.

Plant automation

Enhance efficiency and control with our plant automation solutions, ensuring seamless integration and optimal performance for your operations.

Replacement parts

Ensure reliability and longevity with our high-quality replacement parts, designed to maintain and enhance your plant's productivity.

Site services

Maximize uptime and operational efficiency with our on-site services, gaining expert support and maintenance tailored to your needs.

R&D and Innovation

Enhance processes and technologies to address and anticipate market challenges and trends, for more quality output and performance.

Talk to our experts

Looking to invest in a better future? As an experienced and innovation-driven plant designer, we can deliver the technologies for you to create quality food, feed and biofuel. Our teams of experts are happy to help you with any question.

Contact us