Soybean Decorticating Machine — Efficient Dehulling Technology to Increase Soybean Meal Protein Content

Soybean dehulling is a key process in the production of high-protein feed soybean meal and low-temperature soybean meal. By removing the hull, the protein content of the meal can be significantly increased (reducing cellulose), while also reducing the color and wax content of the extracted crude oil, thereby improving oil quality. Furthermore, dehulling can increase the processing capacity of equipment, reduce the residual oil rate in the meal, and decrease energy consumption during production. The by-product, soybean hulls, can be sold directly or blended in a certain proportion to produce soybean meal grades with different protein contents.

Our equipment is not only suitable for soybeans but can also be used for dehulling other oilseeds such as peanuts, rapeseed, and sesame, meeting the requirements of different production processes.

Soybean Dehulling Process Flow

Raw Soybeans → Drying & Conditioning → Crushing → Skin-Kernel Separation → Kernels (Flaking/Extraction) → Hulls (Collection/Sales)

Soybean Drying and Conditioning Tower

Function: Utilizes a combination of hot air convection drying and heating steam conduction drying to heat and dry soybeans, while adjusting soybean moisture and temperature for conditioning, facilitating subsequent dehulling and flaking.

Structural Features:

• The tower body has a multi-layer structure (9~13 layers, each approximately 1m high), with the number of layers customizable based on output and raw material moisture.
• The inlet section is equipped with a material distributor and level indicator for automatic level control and high-level alarm.
• The conditioning section uses staggered stainless steel elliptical tube banks for high heat exchange efficiency and uniform heating.
• The drying section employs cross-flow drying angle boxes to ensure full contact between material and hot air.
• A variable frequency discharge device interlocked with the level indicator precisely controls the discharge speed.

Advantages:

✅ Uniform heating and good conditioning effect, laying the foundation for subsequent dehulling

✅ Low energy consumption, tower body insulation layer reduces heat loss

✅ Equipped with cleaning windows and fire protection pipelines, safe and reliable

Jet-Type Rapid Dryer (Fluidized Bed Dryer)

Working Principle:

Soybeans enter the dryer evenly distributed via a rotary feeder onto a steel wire mesh conveyor belt (material layer thickness 150~200mm). Hot air is sprayed at high speed from bottom to top through the belt and material layer. Combined with stirring bars that extend into the material layer, the soybeans are turned and fluidized. Within 3 minutes, the soybean surface temperature rises to 85~90°C, instantly breaking the bond between the hull and the kernel, and drying the surface moisture.

Key Parameters:

• Conveyor belt speed: 1270~3810 mm/min (frequency adjustable)
• Hot air temperature: Approx. 140°C (automatically adjusted based on discharge temperature)
• Discharge temperature: 80~90°C

Features:

✅ Fast drying speed, uniform moisture evaporation

✅ Automatic fines removal prevents accumulation and eliminates fire hazards

✅ Circulating air is filtered through a cyclone, collecting hulls and fines, environmentally friendly and clean

Toothed Roll Crusher

Function:

Cracks the conditioned soybeans into several pieces, initially separating the hulls from the kernels for subsequent air classification.

Features:

✅ Adjustable roll gap to accommodate different soybean sizes

✅ Uniform cracking with low fines generation, reducing material loss

Skin-Kernel Air Classifier

Structure:

• Top rotary feeder (with adjustable deflector plates to suit different particle sizes, also acts as an air seal)
• Middle chamber housing multiple rows and columns of impact bars (or staggered baffle plates)
•  Bottom outlet equipped with a rotary airlock valve to ensure system sealing
• Connected to a closed air circulation system, which can be fitted with an air heater to maintain the required temperature

Working Process:

As the cracked beans fall through the classifier, they strike the impact bars (or baffles). The hulls are detached and carried upwards by the counter-current hot air. The rising hulls repeatedly strike the impact bars, releasing any adhering fines. The heavier kernel pieces continue falling and are discharged. The entire process is continuous and efficient.

Advantages:

✅ High separation efficiency, resulting in very low kernel content in hulls and hull content in kernels

✅ Hot air can be used to adjust the temperature and moisture of the kernels, providing conditioning for subsequent flaking

✅ Closed circulation system reduces heat loss, energy-saving and environmentally friendly

Skin-Kernel Separation Plansifter

Purpose: Further screens the material after air classification to ensure the purity of both hulls and kernels.

Screen Configuration:

– Top screen: 5.5~6 mesh (aperture 3.7mm × 3.7mm)

– Bottom screen: 14~16 mesh (aperture 1.5mm × 1.5mm)

By using different mesh size combinations, the rates of kernel in hulls and hulls in kernels can be precisely controlled to meet the production requirements for different grades of soybean meal.

 Equipment Application Advantages

1. Enhance Product Value: Obtain high-protein soybean meal (protein content ≥ 48%) to meet high-end feed demands.
2. Reduce Operating Costs: Decrease solvent consumption and power consumption, improve extraction efficiency.
3.  Flexible Adaptability: Suitable not only for soybeans but also for dehulling peanuts, rapeseed, sesame, and other oil seeds.
4. Safety and Environmental Protection: Closed circulation systems reduce dust emissions, complying with environmental requirements.