100TPD Soybean/Sunflower Seeds Oil Pressing Line in Kazakhstan
The production line can process 100 tons soybean and sunflower seeds every day. The main production processes included raw material storage, screening, stone removal, crushing, softening, flaking, steaming, oil pressing and filtering etc.
According to client’s special requirements, ABC Machinery designed this oil pressing line that can process both soybean and sunflower seeds. The project is divided into three stages, the first stage is 100 tons of soybean and sunflower seeds pressing, the second stage is expected to be 100 tons of oil extraction, and the third stage is expected to be refining and dewaxing.
- Raw Material Reception and Storage
The raw material soybean and sunflower seed are received and stored in storage silo for continuous production.
Screening is based on the difference of particle size between oil seeds and impurities, and the relative movement of oil seeds and screen surface to remove impurities larger or smaller than oil seeds through screen hole. Screening equipment commonly used in oil plants are vibration screen, plane rotary screen, rotary screen, etc. Most screening equipments have an important working component, namely sifter. The size and shape of sieve hole should be determined according to the actual size of oil seed particles.
- Stone Removal
According to the difference of the specific gravity and suspension speed between oil seeds and stones, this method uses the combined action of inclined screen surface with certain motion characteristics and air flow passing through the screen surface to achieve the purpose of grading stone removal. Suction-type specific gravity stone remover is commonly used in grease processing plants. Its characteristics are negative pressure inside the stone remover when working, which can effectively prevent dust from rising out, and the output of the single machine is large, but it needs to be equipped with a separate suction and dust removal system. The blower specific gravity stone remover is equipped with a fan, which has simple structure, but poor working conditions and low output, so it is only used in small oil processing plants.
Before soybean flaking, large-grained soybean must be crushed. The purpose is to make soybean have certain particle size by crushing to meet the flaking conditions. The surface area of crushed soybean increases, which is conducive to the transfer of temperature and moisture during softening, and the softening effect is improved. It is required that the crushed soybeans have uniform particle size, no oil, no agglomeration, less powder, and the particle size meets the requirements. The size of crushed soybeans is 4-6 pieces, and the powder degree of crushed soybeans is controlled to be less than 10% through 20 mesh/inch sieve. The maximum diagonal length of pre-pressed cake after crushing is 6-10 mm. In order to meet the requirement of crushing, it is necessary to control the moisture content of oil during crushing. Excessive moisture content, oil is not easy to crush, and easy to be flattened and release oil. It will also cause crushing equipment not easy to gain material, production reduction, etc. If water content is too low, crushing oil powder degree increases, oil-containing powder is easy to adhere together to form clusters. In addition, the temperature of oil will also affect the crushing effect. Hot oil seeds have smaller powders after crushing, but cold oil seeds have larger powders after crushing. Usually, the suitable moisture content for crushing soybean is 10%~15%. Oil crushing methods include impact, shear, extrusion and grinding. Commonly used crushing equipment are gear roller crusher, hammer crusher, disc sheller. Here, the crushing of soybean chooses tooth roll crusher.
Softening is to improve the elasticity and plasticity of oil by adjusting the moisture and temperature of oil, so that it has the best conditions for rolling billet, reduce the powder degree and sticking phenomenon during flaking, and ensure the quality of flakes. Softening is mainly used for oils with low oil content, low water content and high shell content, which have poor plasticity and hard texture. Soybean has low oil content and poor plasticity, so it should be softened before flaking. The rolling temperature should depend on the moisture content of soybean. When the moisture content of soybean is 13%-15%, the softening temperature is usually controlled at 70-80 degrees and the softening time is 15-30 minutes. The commonly used softening equipment is layer softening pot and drum softening pot. The drum type softening pot with better softening effect is selected here.
Flaking is the process of pressing oil materials from granular to flake by mechanical action. The purpose of flaking is to destroy the cell structure of oil seeds, increase the surface area of oil seeds, and shorten the distance of oil outflow, which is conducive to oil extraction and evaporation. Flaking is the key of pretreatment, which is related to the quality and yield of oil. The key of flaking lies in the operation of flaking machine. In order to ensure the quality of flaking, the moisture and temperature of the material before flaking should be strictly controlled. It is better to set softening box on flaking machine to avoid excessive loss of moisture and temperature after softening. Before starting, the working condition of the flaking machine should be carefully checked. If the uneven thickness of flakes at both ends or the oil without rolling is mixed into the flakes, stop checking and adjust the rolling distance (both sides should be balanced, and too tight adjustment should be avoided). Check whether the scraper is close to the surface of the roll to prevent roll sticking. Pay attention to the uniformity of flow to prevent no-load operation. Generally, the thinner the oil is rolled, the more damaged the cell structure is, and the better the oil extraction effect is. The requirements for flaking machine are thin and uniform flakes, small powder and no oil leakage. Whether oil is obtained by pressing or by extraction, the thickness of flakes has a great influence on oil yield.
- Steam Cooking
This step aims at increasing the inlet temperature of oil flakes, so that they can bring out more oil.
- Oil Pressing
Oil flakes are then fed into the screw oil press. The screw oil expeller uses friction and continuous pressure from the screw drives to move and compress the oil flakes. The oil flakes go through small openings that do not allow seed fiber solids to pass through. Afterward, the pressed oil flakes are formed into a hardened cake, which is removed from the machine. Pressure involved in expeller pressing creates heat in the range of 140–210 °F (60–99 °C). Raw materials are typically heated up to 250 °F (121 °C) to make the pressing more efficient, otherwise the pressing itself will heat the oil to 185–200 °F (85–93 °C).
- Oil Filtering
Oil filtering can filter the raw pressed oil to remove impurities in the oil, and this makes the later oil refining process much easier.