Rapeseed pre-pressing extraction machine
Double-low rapeseed originated in Canada. Canadian purchases require rapeseed to contain less than 2% impurities, 6-9% moisture, 42-44% oil, 25% protein, and 25% carbohydrates. Canada revised the definition of double-low rapeseed in 1996, revising the content of erucic acid in double-low rapeseed oil <1%, and the content of glucosinolate in meal <20umol/g. The oleic acid in double-low rapeseed oil is more than 60%, the linoleic acid reaches 20%, and the linolenic acid reaches 10%. In addition, high-oleic double-low rapeseed is cultivated and produced, and the oleic acid content is >72%.
Process flow of rapeseed oil pre-pressing extraction machine
Rapeseed--Measurement--Magnetic Separation--Screening--Conditioning--Peeling--Rolling--Steaming and frying oil pressing--Leaching
The main operating points of rapeseed oil pre-press extraction machine
2.1 Storage
Rapeseed moisture < 8%, impurity < 4%, stored in a place without ventilation for two months. If the moisture content of the rapeseed is 8-10%, and it is stored in a place without ventilation for 15-30 days, it is necessary to observe the temperature change of the rapeseed online. When the moisture content of the rapeseed is >10%, it must be dried before entering the warehouse
2.2 Magnetic separation cleaning
Use a magnetic separation drum to remove iron, and use a flat rotary sieve to screen with a layer of sieve surface. The front section of the sieve hole is Ø6 and the back section is Ø4. It is required that the rapeseed contains less than 1% impurities after cleaning.

2.3 Conditioning and softening
In order to moisten and evenly transfer mass, build 2 small stainless steel silos in front of the tempering, spray water before feeding, keep the rapeseed wet for 6-12 hours according to the quality of the rapeseed, and control the water content to 9-10%. Before the rapeseed enters the conditioning tower, it first passes through the skin suction device to absorb light impurities. Rapeseed conditioning uses a vertical conditioning tower, pay attention to the frequency of the fan, the conditioning hot air is at 60-70°C, the dehydration capacity is about 2%, the heating layer uses 0.07MP-0.08MP steam, and the rapeseed passing time is 35- 40min
2.4 Peeling rapeseed
The combination of the skin and kernel of rapeseed is mainly in the germ part, and most of the subcutaneous parts are independent of each other. Cutting, extrusion, and rubbing are adopted to produce deformation in the crushing roller. The deformation causes the rapeseed skin to break, thereby making the kernel The meat (leaf and germ) is separated from the skin, the crushed mixture in the first step is passed through a flat rotary sieve, the kernels under the sieve are directly pressed, the incompletely broken rapeseed on the sieve is crushed for the second time, and the mixture of the middle skin and kernels is air-selected Hulls and kernels are removed; no broken rapeseed is subjected to a second cracking. It is also possible to dry the rapeseed with 7-8% moisture in the hot air to remove free moisture and bad smell. The skin and the rapeseed kernel expand with heat and contract with cold, and the rapeseed is broken by centrifugal impact on the baffle. Control peeling 12%, powder degree 2-3%, after the skin and kernel are separated, the kernel contains <4% skin, and the kernel contains <3%
2.5 Rolling
The temperature is 50-55°C, the moisture content of rapeseed is 7-9%, and the thickness of the green sheet is 0.25-0.35mm
2.6 Horizontal seed frying machine
Rapeseed stays for 30-40min. The outlet temperature is 100-105°C, the moisture is 3.5-5%

2.7 Squeeze
The ZX338 press is adopted, the pressing temperature is ≥95°C, the water content is 4-6%, the cake thickness is 10-11mm, the residual oil is adjustable in the range of 16-18%, and the back-pressing amount is 13%. If the pressing temperature is above 105°C, the water content is 4-4.5%; if the pressing temperature is 90°C, the water content is 5.5%. The oil that enters the oil press needs to be kept warm and pre-pressed. A knife is installed at the cake outlet behind the oil press to break the cake. Inside the press chamber, it is necessary to consider the installation of the press bar, press screw and fast resistance.
If a German Vorpress oil press is used, the pressing temperature is 110°C, the moisture is about 6%, the cake thickness is 8-10mm, the cake moisture is 8-9%, the cake residual oil is 17-21%, and the pressing time is 30-35Sec. The feed section of the press is equipped with a pre-pressing device

2.8 Flap cooler
The hot air temperature is set at about 50-60°C, cooling and precipitation are carried out, and the temperature of the leaching device is kept at about 55°C
2.9 Cake Conveying & Filtration
Scraper conveyor should be used for machine-pressed cake transportation to reduce powderiness. The squeezed oil passes through the slag extractor, and after the oil tank is clarified, it passes through the horizontal centrifuge. The solid impurities are ≤0.2% and the moisture is 0.1%.
Discussion on the processing series of rapeseed oil pre-pressing and leaching machines
3.1 Moisture and impurity requirements for incoming rapeseed
Rapeseed is low in carbohydrates, and carbohydrates can bind some water, so it contains low free water. If the free moisture is high, it can accelerate the metabolic reaction of rapeseed and increase the growth of microorganisms. During the storage process, lipids, carbohydrates and proteins are degraded into carbon dioxide, water and heat, which will increase the temperature and breed microorganisms. Water and temperature are the driving force for degradation. If not controlled, the deterioration of oil will be aggravated
3.2 The difference between softening and tempering
Adding water and heating up the rapeseed to each layer of the material layer of the softening pot has a good effect of adjusting the elasticity and plasticity of the oil. The tempering tower has good precipitation performance, and is lower than the softening pot in terms of water absorption
3.3 Horizontal seed frying machine instead of steaming wok
The electricity consumption of the horizontal frying machine is 1/4 of that of the vertical steaming and frying pan, but the vertical frying pan has the functions of steaming and frying. At 100-150°C and 1.5h, it has a great effect on the denaturation and aggregation of oil cell protein, and the cell wall ruptures. , the oil circuit is opened. The technical effect of the horizontal frying machine is worse than that of the steaming wok. It only has the function of frying, but the effect of frying seeds and precipitation is good, and the temperature is fragrant.
3.4 The relationship between the impurity content, solids, oil content, temperature and moisture of rapeseed in the press chamber of the oil press
The kernel and flesh of rapeseed are mainly combined in the germ part, and most of the subcutaneous parts are independent of each other. As the pressure of the pressing chamber increases, the oil outflow channel becomes narrower, and the pressure and consumption increase. The skin content decreases from 16-17% to about 4%, which has almost no effect on the pressure. When it continues to decrease by 2%, the pressure rises, indicating that the outflow channel of the solid deformed oil becomes smaller rapidly, and the oil flows out slowly. A long relaxation time is provided to allow the oil to flow out, so the rheological requirement of the oil is to maintain a certain amount of peeled rapeseed in the press.
As the moisture of rapeseed increases, the solid pressure in the pressing chamber decreases, but the solid pressure has nothing to do with the pressure along the pressing axis. Water and cell walls colloidally bond and shape, and oil flow decreases as pressure increases. Therefore, it is required that the rapeseed contains 3-4% skin and 4% moisture during cold pressing, and the unpeeled rapeseed is pressed at a temperature of 105-110°C and a moisture of 4-4.5%.
The slag oil content of the slag machine is 60%, and the slag discharge is 15-20%. The inner smooth bore cannot build up the pressure of the squeeze chamber, and the residual oil rises.
In order to get comfortable pressing, achieve the best solid pressure and best drainage, pay attention to water content, hide content, temperature and pressing conditions.
3.6 Add an extruder behind the oil press
The phospholipid is modified, and part of the hydrophobic phospholipid is converted into a hydrophilic phospholipid, which facilitates the production of four-grade rapeseed oil. The protein gel and machine-pressed rapeseed cake show bulkiness, air permeability and increase in bulk density, which is beneficial to the penetration of leaching solvent and solvent stripping recovery in DT. The residual oil of leaching rapeseed meal is reduced by 0.2-0.3%, and the control Meal residual oil ≤ 1.1%, residual solvent ≤ 500ppm, pre-pressed crude oil phosphorus content 300-350ppm, pre-pressed puffed leaching oil phosphorus content 600-800ppm
3.6 Degumming to produce four-grade rapeseed oil
Moderately add 75% phosphoric acid, dilute alkali 12-16 degrees Baume, the production of grade 4 oil remains transparent in winter and does not become hazy. Rapeseed oil contains pheophytin, prolonging the frying time for 40 minutes and the temperature above 115°C can eliminate the blue light of part of the rapeseed oil