Rapeseed oil production line

There are two main ways to prepare rapeseed oil, one is the pre-e­xpression extraction method, and the other is the pressing method. From the perspective of return on investment, production projects with an output of more than 30 tons/day are suitable for the pre-e­xpression leaching method. If the output is 1-10 tons/day, the cost of oil production by the pretreatment pressing method will be lower. The equipment used in the two production methods is also different.

1. Press method

Rapeseed —→ Magnetic separation —→ Screening —→ De-stone —→ Rolling embryo —→ Steaming and frying —→ Pre-pressing —→ Squeezing
Before pre-pressing, we need to pre-treat the oil, clean up the impurities in the oil, and adjust the temperature, humidity and moisture of the rapeseed to make it reach the good state before pressing. Rapeseed pretreatment equipment includes magnetic separator, vibrating screen, stone removing machine, embryo rolling machine, steaming pan and other equipment. After pretreatment, we use a pre-press and a press to press twice to produce rapeseed oil.

2. Pre-e­xpression extraction method
Rapeseed-cleaning-embryo rolling-steaming-squeezing-filtering-leaching system-wet meal desolventizing system-mixed oil treatment system-solvent recovery system-degumming-deacidification-decolorization-deodorization
The pre-e­xpression extraction method also requires pre-treatment and pre-e­xpression of rapeseed, which is the same as the pre-e­xpression method. After pre-pressing, we obtain crude oil and cakes. The oil content in the cake is about 7%, which can be extracted by leaching. Leaching is a process in which the oil in the cake is extracted by using a solvent that is compatible with the oil by using the principle of extraction. Under normal circumstances, the residual oil rate of the cake after leaching is less than 1%.

Both the rapeseed oil obtained by pre-pressing or the rapeseed oil obtained by leaching contains trace impurities. In order to obtain high-standard edible oil and make the storage time of the edible oil longer, we need to refine the crude oil.

Rapeseed oil refining usually refers to the removal of harmful impurities and odorous substances from crude oil through degumming, deacidification, decolorization, and deodorization to obtain edible oil that meets the standards. There are three common refining equipment: batch refining equipment, semi-continuous refining equipment and full continuous refining equipment. Depending on the output, the budget, and the requirements for refined oil, the choice of refining equipment is naturally different.

Rapeseed oil extraction process is as follows:

Hot pressing: cleaning the rapeseed-softening the embryo-steaming and squeezing? Operating instructions: the rapeseed is selected with a 30 mesh/inch screen to make the rapeseed less than 0.5% of impurities, and then softened and softened After the rapeseed has a moisture content of about 9%, it can be rolled embryos, steamed and stir-fried, and steamed and stir-fried to make the oil temperature reach 110-120 degrees, and its moisture content is about 1-1.5%, then it can enter the oil press for pressing. If you use a cylindrical frying pan, the rapeseed can directly enter the cylindrical frying pan after cleaning and removing impurities, or enter the flat-bottom frying pan after rolling the embryo.

　　 But when the seeds are fried, add 2-3% water, and when the temperature reaches 110 to 120 degrees, it can be squeezed out of the pot. When hot pressing, the following methods can be used to judge whether the rapeseed is fried well. Rub the rapeseed with two wooden boards. If the shell and kernel are separated, the kernel becomes dark yellow. If the kernel becomes powder, it is too dry, and if the shell and kernel are not separated, it is too wet.

Cold pressing: Rapeseed can also be cold pressed. During cold pressing, the rapeseed can be cleaned and removed. You can add l-12% water to soften the rapeseed. After softening, the embryo can be pressed. It can also be pressed in the oil press without the embryo. , (But pressing after the embryo rolling can improve the performance of the oil press) The moisture content of the rapeseed during cold pressing will directly affect the oil output efficiency, so it is very important to judge the dryness and wetness of the oil. Generally, the rapeseed before pressing The moisture content is controlled at 5-8%. Use the soil method to judge the moisture content of the rapeseed. You can squeeze the rapeseed with your nails. If it makes a noise, divide it into two pieces, squeeze out the oil to make the moisture content suitable, if it is powdered The moisture content is low and too dry. If it is flat, the moisture content is high and too wet.

Problems that are prone to occur during the pressing process: the oil content in rapeseed is as high as about 33-40%. Normally, there will be no abnormal phenomena in the operation according to the instruction manual during hot pressing. If the cold pressing is due to improper operation or the moisture content of the oil is not suitable, The temperature of the rapeseed oil press is not good, and there will be some phenomena such as slag runoff, oil return, or poor feeding. At this time, you can refer to the cold pressing of peanut kernels for processing.

　　 Rapeseed oil is a semi-drying oil containing erucic acid. Except for canola oil, other varieties of rapeseed oil contain more erucic acid, which accounts for about 26.3% to 57% of the fatty acid composition. The nutrition of high erucic acid rape oil is not as good as that of low erucic acid oil, but it is especially suitable for manufacturing marine lubricants and tires and other industrial oils. In the oil production process, glucosinolates are hydrolyzed by the action of myrosinase, forming some sulfur-containing compounds and other toxic components, thus affecting the quality of crude oil. The general rough refining process has very low removal rate of sulfide, so edible rapeseed oil should be refined.

Operating conditions: the initial temperature of alkali refining is 30～35℃, the final temperature is 60～65℃, the concentration of lye is 16°Bé, the amount of excess alkali added is 0.2%～0.25% of the oil, plus 0.5% of the oil The neutralization time is about 1 h, and the sedimentation time is not less than 6 h. Alkaline oil refining washing temperature is 85-90℃, the first washing water is dilute saline alkaline water (alkali concentration 0.4%, adding 0.4% salt), and the adding amount is 15% of the oil. After that, wash it several times with hot water until the soap content of the alkali refining is not more than 50 ppm. When decolorizing, first vacuum dehydration for 30 minutes, temperature 90℃, operating absolute pressure 4.0kPa, and then add activated clay for decolorization. The amount of clay added is 2.5% to 3% of the oil, the decolorization temperature is 90 to 95 ℃, and the decolorization time is 20 minutes. Cool to below 70 ℃ and filter. The decolorizing filter oil is heated to 100℃ by vacuum suction deodorization tank formed by the first and second steam jet pumps, then turn on the third and fourth stage steam jet pumps and atmospheric condenser cooling water, the deodorization temperature is not less than 245℃, operation The absolute pressure is 260～650Pa, the water temperature of the atmospheric condenser is controlled at about 30℃, the direct steam pressure of the stripping is 0.2MPa, the input amount is 8-16 kg/th, the deodorization time is 3-6 hours, and the deodorization is completed and cooled to 70℃ in time Filter again.

　　 refined rapeseed salad oil refining process (fully continuous)

　　 phosphoric acid lye

　　↓ ↓

　　Filter crude oil—→preheat—→mix—→oil-alkali ratio—→mix reaction—→desoap—→soap feet

　　↓

　　Filter←—Distillation deodorization←—Filtration←—Adsorption decolorization←—Drying←—Dehydration←—Washing←—Soft water

　　↓ ↓ ↓ ↑ ↓

　　 Rapeseed salad oil, water vapor, waste clay, adsorbent, waste water

Operating conditions: the impurity content of the filtered crude oil is not more than 0.2%, the lye concentration is 18-22°Bé, the amount of excess alkali added is 10%-25% of the theoretical amount of alkali, and sometimes 0.05%～0.20% of the oil is added first Phosphoric acid (concentration is 85%), the desoaping temperature is 70-82℃, the washing temperature is about 95℃, and the soft water addition is 10%-20% of the oil. Continuous vacuum drying and dehydration, the temperature is 90～95℃, the absolute operating pressure is 2.5～4.0 kPa. The adsorption decolorization temperature is 105-100 ℃, the absolute operating pressure is 2.5-4.0 kPa, the operating time at the decolorization temperature is about 30 minutes, and the amount of activated clay added is 1% to 4% of the oil. The filtration temperature when using a vertical leaf filter to separate the white soil is not less than 100°C. P≤5 ppm, Fe≤0.1ppm, Cu≤0.01ppm in decolorizing oil. Deodorization temperature is around 240～260℃, operating absolute pressure is 260～650Pa, stripping steam is fed in 0.5%～2% of oil volume, deodorization time is 40～120min, citric acid (concentration 5%) is added at 0.02% of oil volume %～0.04%, the safe filtration temperature is not higher than 70℃.