Before the oil is prepared, the pretreatment of soybeans requires cleaning, crushing, softening, rolling, extruding, etc. for the soybean oil processing industry.
1.1 Soybean Cleaning
Soybean should be cleaned first. The main purpose of this section is to remove the impurities of soybeans. The impurities are mainly plant impurities (such as bean stems, pods, etc.), metal impurities and non-metallic impurities.
1.1.1 Main equipment
- Magnetic separator: adopts magnetic force to remove metal impurities by using the magnetic difference of various ores or materials, the metal impurities are usually nails, small iron wire, etc. Removal of metal impurities avoids the abrasion on the machine in the subsequent work.
- Vibrating cleaning screen: The raw material may contain soil, leaves, stems and other ball impurities, which need to be cleaned up before the subsequent process. High-frequency vibration equipment can effectively remove impurities by using differences between oil and impurities in particle size, with the help of the relative movement between impure oilseed and sieve surface, finally, the impurities larger than or less than oilseed can be removed through the sieve hole. This kind of cleaning sieve is suitable for medium and large factories.
1.2 Soybean Crushing
After cleaning, the soybeans are sent to the crushing section, the main purpose is to crush the soybeans and separate the soybean skins from the bean kernels.
1.2.1 YPSG series toothed roll crusher
Generally, soybeans are required to be broken into 4 to 8 valves, and the powdery degree (when crushed beans passing through 20 meshes screen) is less than 10%. The crusher is preferably a toothed roll crusher with cutting, impacting and bending effects. YPSG series toothed roll crusher is mainly used for crushing such large granular material like soybeans, so as to produce the excellent embryo and improve the yield. The machine has the characteristics of small noise, high output, uniform crushing granularity, low power consumption, small footprint, simple structure, flexible and reliable, convenient maintenance and so on.
1.2.2 Purposes of crusher
- Crushing makes the oil material with a certain granularity to facilitate compact rolling.
- Crushing increases the surface area of the oilseed, which is conducive to the transfer of temperature and moisture in the softening process of the oilseed and ensure the softening effect.
- The seeds are crushed into small granules, which is good for the next oil press section.
1.3 Soybean Softening
Softening is through the adjustment of oilseed moisture and temperature to improve the elasticity of seed so that it has the best conditions for rolling. Softening is mainly used for seeds with low oil content, low water content, poor physical properties and hard texture. Soybeans have low oil content and poor plasticity, which need to be softened before rolling. Softening temperature should be based on the level of soybean moisture. When soybean moisture is 13%~15%, the softening temperature is usually controlled at 70~80℃, and the softening time is 15~30 minutes. The commonly used softener for soybeans is a horizontal softening pot, which has a better softening effect.
1.3.1 The main function of softening
- It gives the soybean kernel certain plasticity and makes it easy to roll out the thin flakes when flaking.
- Softening can reduce the powder degree and sticky roller phenomenon, to ensure the quality of the flakes.
1.3.2 Working principle of horizontal softener
The material enters the drum through the inlet, and with the rotation of the drum, the material is constantly turned over. Meanwhile, the drum is equipped with a heating tube and steam is passed through the tube, the material is heated, steamed and rotated at the same time. According to the softening condition of the material, the softening time of the material can be controlled by adjusting the rotating speed of the rotary drum to optimize the softening effect.
1.3.3 Features of horizontal softener
- The rotation of the horizontal softening pot makes the material turn over more evenly, and without dead angle. With the improvement of avoiding the dead angle of layer softening pot, which causes the phenomenon of burnt paste, the horizontal softener can soften the material evenly and thoroughly.
- The horizontal softener avoids the abrasion of the scraper and heating layer, so the equipment has long service life, low failure rate and low maintenance cost.
- Because of its unique structure, the volume of horizontal softening pot is much smaller than that of layer type, the arrangement of it in workshop is easier, the area of occupation is small, and the investment of equipment is greatly reduced.
1.4 Soybean Rolling
Soybean rolling is the process of using the mechanical function to roll the oilseed from the granular to flake.
1.4.1 Purpose of soybean rolling
The purpose of rolling is to destroy the cell structure of oilseed, increase the surface area of seed and shorten the distance of oil flowing out, which is beneficial to the extraction of oil. In order to ensure the quality of rolled flakes, the moisture and temperature of materials before rolling should be strictly controlled.
1.4.2 Soybean rolling equipment structure
- Feeding mechanism: keep flowing and distributing uniformly
- Roller: main working part
- Distance adjusting device: spring type, lever type, hydraulic type
- Baffle and scraper
- Transmission device
1.5 Soybean Extruding
Soybean extruding is the process of using extrusion equipment to break through the crushed, rolled soybean into porous, expanded granular material. Extrusion is a kind of high temperature and short time processing. At present, the commonly used soybean extruding machine is low moisture single-screw extruder, and the material is extruded by heating, pressing, gluing and vacuum extrusion. Generally, extrusion temperature can reach 110~200℃, and the residence time in the extruder is for the l~3 minutes.
Oil pressing is a mechanical extracting method by using screw press to squeeze oil out from clean materials under pressure. The capacity of oil screw press is from 1 to 50 tons per day, which are commonly used for continuous mechanical extraction of oil these days, regardless of the size of the operation. There are many factors that affect the efficiency of oil extraction, such as vegetable seed types, temperature, press configuration, etc. Usually, the physical pressing method has an oil output of 65-70%, which is suitable for commercial processors to build small and medium screw pressing oil plant.
Today, the soybean oil is divided into cold pressed oil and hot pressed oil. The cold-pressed soybean oil has a lighter color and a lighter raw smoky taste. The hot-pressed soybean oil has high oil yield due to the high-temperature treatment of the raw materials, but it has a darker color and a stronger green bean odor. Therefore, the commonly used oil screw pressing method is cold pressing: the physical pressing method has irreplaceable technological advancement for the pursuit of green, authentic, healthy food. In order to achieve additional oil recovery, the seed material must be subjected to a longer retention time of high pressure in the screw press. Higher pressure is mainly achieved by lower seed moisture, resulting in high friction in the press. Because of the mechanical strength, the maximum diameter of the press cage is determined. The higher the pressure, the more limited the capacity of the press is. Moreover, the longer the retention time is required, the lower the shaft speed is required. This further limits the capacity. Therefore, the cold press is characterized by a capacity of only 1/10 of the capacity of the modern pre-pressing machine. But cold press machine can screw out 80~90% oil from seeds. This means that the total remaining oil content in the full-pressed cake is around 10~20%.
1. Lyzx24 cold pressing machine
Lyzx24 cold press is a new generation of spiral oil press designed for the cold pressing of various oils, especially suitable for mechanically squeezing organic plants and high value-added commercial crops. The cold pressing machine is suitable for squeezing soybean, rapeseed, peanut, etc., Lyzx24 pressing machine could be equipped with single-screw or twin-screw structures. Based on the single-screw press, a twin-screw cold-pressing machine is developed with the improvements of superior mechanical properties and high oil production rate and optimized stamping process, which produces high-quality oil and cold-pressed cakes with high efficiency. If the seed has high oil content, it should be added double press to obtain maximum yield.
2. Cold pressing features
- The pressing temperature is low, the oil yield is high, the residual oil is low, the cake protein is less denatured, the processed oil color is relatively shallow with good quality and rich nutrition, which meets the oil standard on the international market.
- The cold pressing machine is suitable for squeezing soybean, rapeseed, peanut, teaseed kernel, sunflower seed kernel, cottonseed kernel, etc., widely applicable and multifunctional.
- Lyzx24 pressing machine is equipped with temperature and moisture control devices, easy operation.
3. Lyzx24 cold press technology data
|Oil content in cake
1. Superfine Fragrant Soybean Oil Refining Process
This workshop adopts the production technology of batch refining. According to the type and quality of the crude oil, the process parameters are adjusted and different refining methods are selected to produce the first and third-grade oils. The process equipment we provide has the following features:
- Flexible and convenient adjustment system, slight changes in raw material quality can still be normally produced.
- Maximum heat recovery, significant energy savings.
- The fully enclosed operating system avoids the oxidation of oil and ensures the high quality and stability of the products.
- The use of advanced physical refining processes has effectively increased the refining rate. At the same time, the amount of sewage and the sewage treatment costs are greatly reduced.
2. Soyoil Refining Process Flow
Crude oil→Heating→Mixing→Alkaline reining→Precipitate separation→Heating→Washing→Separating→Vacuum drying and decolorizing→Deodorization→Cooling→Filtrating→Finished oil
3. Soyoil Refining Process Instructions
- Alkaline refining operation: Adjust the oil temperature to around 60℃, then, add 20~30°Bé into the pot within 5~10 minutes and stir for 5~10 minutes under the mixing speed of 60r/min. Observe the separation of soap particles after the reaction, meanwhile, start to heat the mixture and slow the speed of stirring. When the temperature reaches 65℃(Approximately 1 degree per minute), separation of oil soap is obvious, stop stirring, start to stand still the mixture to settle soap foot, it generally takes 4 to 6 hours to release the soap foot.
- Washing: After releasing the soap foot, the oil is further heated to 75℃, and then hot water is added for washing and stirring. The water temperature should be 5℃warmer than the oil temperature since too low water temperature is easy for emulsification. After the addition of water, continue to stir the oil for five minutes, then it takes four hours for the oil sedimentation, and finally, soap water is discharged. Oil washing can be repeated 1 or 2 times, depending on the quality of the oil.
- Vacuum drying and decolorizing: First, turn on the vacuum pump: the vacuum degree≥ Next, the washed, alkali-refined oil is sucked into a decolorizing pot, and the oil is heated to about 100℃ while stirring under vacuum condition, then stirring for 10 minutes to reduce oil’s moisture content to 0.1% or less. After that, clay or active carbon is added to the pot(the additive amount of decolorizing agent is 2~4% of oil amount), stirring for 20 minutes. Next, stop heating until the temperature is less than 90℃, after the vacuum pump is turned off and the decolorization of the pump is turned on, oil is pumped to the oil filter for filtering. The product oil is separated in the oil filter to obtain the refined oil.
- Deodorization(alternative): Decolored oil→oil-feed pump→No.1 oil heat exchanger→No.2 oil heat exchanger→No. 3 heat conduction oil heat exchanger→Deodorization tower→ Shielding pump→No.2 oil heat exchanger→No.1 oil heat exchanger→Product oil
4. Main Equipment for Refining Soybean Oil
||Alkali and water washing for oil, stainless steel
||Used to dry oil and remove oil pigment
||Separation of oil and clay
||Removal of acid, odor substances and volatiles from oil, stainless steel
||High-efficiency vacuum pump
||Vacuum generating device
||Thermal oil furnace
||Provide heat energy for production, temperature up to 300℃
||Vapor heat exchanger
||Production of steam
||Separation of deodorized saturated steam’s excess moisture