A vertical cooker (also known as a vertical conditioner or digester) is a large, cylindrical industrial equipment composed of multiple stages (overlapping trays) heated by steam. It is used for the thermal and mechanical pre-treatment of oilseeds before mechanical pressing or solvent extraction.
The equipment operates continuously: the material (flaked grains, broken grains, or germ) enters at the top and descends by gravity through the various stages arranged in a column.
- Heating and cooking: Indirect steam jackets at the bottom and walls of the trays (in addition to direct steam injection when necessary) raise the temperature of the mass between 80 °C and 110 °C.
- Homogenization: Mechanical agitators mounted on a central vertical shaft keep the material in constant motion in each tray, ensuring uniform distribution of heat and moisture.
- Level control: Automatic rotary doors and valves regulate the passage of the mass from one stage to another, controlling the retention time. Industries that use:
- Vegetable Oil Processors and Grain Crushers:
Soybeans: Preparation of flakes for solvent extraction and production of crude oil and meal.
Cotton: Conditioning of cottonseed linter/beans before mechanical presses.
Sunflower and Canola: Tissue rupture and viscosity control.
Corn: Processing of corn germ obtained from dry or wet milling.
Peanuts and Castor Beans: Direct pressing in mechanical extraction facilities.
- Biodiesel Plants: As a preliminary step in the extraction of crude vegetable oil used as raw material for transesterification.
- Rendering Plants and Animal Fat Industry: Adaptations of this type of vertical digester for cooking and drying animal by-products (offal, bones and fats from poultry, cattle and swine).
Types of Oil Cookers/Conditioners:
- Multi-Stage Vertical Cooker (Plates/Trays): Vertical cylindrical column divided into overlapping chambers. The material descends by gravity while a central shaft with stirring blades ensures agitation.
- Horizontal Cooker/Conditioner (Tubular/Drum): Cylinder in a horizontal position equipped with an internal bundle of heated tubes or a helical screw.
- Fluidized Bed/Hot Air Conditioner: Uses heated air currents forced through perforated surfaces. Designed for rapid heat exchange and removal of surface moisture without prolonged exposure to heat.
- Expanders and Extruders: High-pressure, mechanically shearing equipment (HTST technology). They process the mass in a few seconds before sending it for solvent extraction.
Classification by Heat Transfer Method:
- Indirect Steam: Saturated steam circulates exclusively through the interior of the chambers, side jackets, or tubes, without coming into direct contact with the seed. It heats the mass by pure conduction without adding water to the process.
- Mixed (Direct and Indirect Steam): Combines indirect heating chambers with nozzles for direct steam injection into the mass. Promotes rapid gain in temperature, humidity, and plasticity in the raw material.
Industries that use cookers/conditioners for oils are mainly divided into the following sectors:
- Vegetable Oil and Grain Crushing Industry: Production of edible food oils (soybean, corn, sunflower, canola, cottonseed, and peanut) and lecithin.
- Cocoa and Chocolate Industry: Treatment of cocoa nibs for pressing and extraction of cocoa butter.
- Margarine and Vegetable Fat Industry: Processing of crude oils for the manufacture of baking fats, biscuits, and margarines.
- Animal Nutrition and Feed Industry (Pet Food and Livestock): Production of highly digestible protein meals (such as soybean meal without antinutritional factors) and addition of fats to animal feed.
- Rendering Plants and Slaughterhouses: Cooking and dehydration of animal offal, bones, and fats for the recovery of beef tallow, poultry fat, and protein meals.
- Biodiesel Plants: Extraction and preparation of crude vegetable oils and animal fats as raw materials for biofuels.
- Cosmetics and Pharmaceutical Industry: Extraction of pure and special vegetable oils (such as castor oil, almond oil, and sunflower oil) for use in cosmetics, creams, and pharmaceutical ingredients. |
