Peanut oil processing technical instructions
1.Cleaning
The same equipment as ordinary secondary oil
2. Classification
Immature, moldy, broken and other incomplete grains in peanuts are separated through grading screens. This part can be used to produce secondary oil and is sold separately.
3. Drying/cooling
Drying equipment can be equipped with hot air dryer. After drying, the moisture content of peanuts is controlled within 5% to 6%. Then quickly use cold air to reduce the temperature of the oil particles to below 40°C.
4. Crushing/peeling
The crusher can be a toothed roller crusher, the purpose is to remove infrared clothes. After crushing, use a wind separator or suction plate to suck out the infrared clothes. The isolated red skin of peanuts can be used in the pharmaceutical and chemical industries. raw materials.
5. Hot air roasting
25%-30% of the total amount of peanuts is sent to the coal-fired hot air roasting furnace, where the oil is heated to 180℃~200℃. Roasting temperature is a key factor in the aroma of fragrant peanut oil. If the temperature is too low, the smell will be weak; if the temperature is too high, the oil will precipitate easily.
6. Cooling and rolling
In order to prevent the oil from gelling and spontaneous combustion, heat should be quickly dissipated and the temperature should be lowered after baking. After cooling, use a toothed roller crusher to break it into particles.
7. Steaming and stir-frying
"Use a five-layer vertical steamer to cook the green body. The 1st to 2nd layers should be filled with steam; the 3rd to 5th layers should be shallow to remove moisture; the exhaust temperature is 108℃~112℃, The moisture content is 5% to 7%. In order to ensure that the peanut oil has a rich aroma, the indirect steam pressure of the steamer should not be less than 0.6mpa.
8. Hydraulic pressure
This process uses a 200-type screw hydraulic press. Taking into account the particularity of the peanut oil production process, the main shaft speed of the hydraulic press can be appropriately adjusted and the main shaft speed can be increased from the original 8 rpm to 10 rpm. The thickness of thick cakes is usually controlled at about 10mm. The pressing temperature is 135°C, the pressing moisture is 1.5%-2%, and the residual oil in the pressed cake is 9%-10%.
The obtained crude oil is precipitated and filtered with a vertical leaf filter and then sent to the refining workshop.
Specific operation methods of peanut oil refining
(1) Rapid transportation of peanut oil. Before pumping filtered crude oil into the refining tank, please check whether the pipeline valve is normal. After each tank has finished sending oil, the oil inlet valve should be closed immediately. In order to refine crude peanut oil in an oil tank, the foam on the oil surface must be removed first to make the oil surface smooth and left for an appropriate time (not less than 15 minutes) so that there is no foam in the oil. Adjust the crude oil temperature to 25-35°C.
(2) Preparation of alkali solution: Weigh the specified amount of NaOH (the purity must be determined first), mix it with an appropriate amount of water, stir, start the alkali pump, and circulate the alkali solution to completely melt the NaOH. Reduce the temperature of the alkali solution to 25-30°C, let it stand for 20 minutes, measure the Baume degree of the alkali solution with a Baume meter, and adjust it to 10--12°Be.
(3) Mixing alkali When the oil surface of the crude oil is smooth and the temperature is stable at 25-35°C, turn on the stirrer and start stirring. First stir slowly (20r/min) for 1 minute, then switch to rapid rotation (40r/min) while stirring. , open the alkali tank valve and put in the alkali solution. The time for adding lye is usually about 15 minutes. After adding the lye, continue stirring quickly until the oil and soap particles are clearly separated. The stirring time is about 3-3.5h. When the oil and soap stock are clearly separated, turn to slow stirring, open the heating steam door (steam pressure 1.4kgf/C㎡), and raise the oil temperature to 60℃ (the oil temperature should be maintained at a high of 1℃/min (the temperature should not be over 65℃).
(4) Wash the oil sent by the heating pump to the washing tank to increase the temperature, and at the same time turn on the agitator to add 75-80°C hot water to keep the oil temperature at 80-85°C (the temperature shall not exceed 85°C). When adding water (the amount of water added is 15%-20% of the oil, the water adding time is 38-40min), stop heating and continue stirring for 15 minutes, that is, stop stirring, let it stand for 2h (for the first time), and rinse the bottom of the tank with water. Open the drain valve and release about 3/4 of the flushing water (before releasing the flushing water, pour the oil in the pipe into the oil-water separation tank to recover). Then close the discharge valve, open the valve to the oil-water separation tank, and then slowly add the remaining oil-water mixture. For the first cleaning, all the viscous middle layer of oil and water must be put into the separation tank until good oil is seen, and then the valve is closed.
Oil-water separation must be controlled by dedicated personnel. When separating in the separation tank, the heating coil in the separation tank must be turned on and the temperature must not exceed 80°C. After separation, water will be released to recover the remaining oil.
Continue to clean the oil machine with water according to the above method until the cleaning water is completely clear. The settling time for the second wash is 1.5h.
(5) Before dehydration and transportation, check whether the valves of the relevant pipelines are normal, and then pump the washer oil into the vacuum dehydration box. At the same time, open the steam valve, start the vacuum pump and agitator, adjust the cooling water of the condenser, and start the circulating oil pump to accelerate the oil circulation in the vacuum dehydration tank. The vacuum degree of the vacuum dehydration tank is maintained above 0.0867MPa. The dehydration time is about 3 hours, starting from the oil delivery volume in the dehydration tank, and the dehydrated oil should be sampled and inspected by a quality inspector. When insufficient dehydration is found, dehydration must continue. The dehydration temperature is maintained at approximately 70°C.
After dehydration is completed, stop the vacuum pump, open the air valve, and slowly add air. Check whether the pipeline valve is normal, then cool the delivered oil to 25-30°C through the cooling pipe, and then flow into the sedimentation tank for pressure filtration.
(6) Check whether the valves in the filter press pipeline are normal. Check that the oil temperature must be below 30°C. After the oil is filtered, stop the oil filter pump to close the valve, gently open the filter plate to allow the internal oil to flow into the oil pan, and then remove the filter residue on the filter cloth. Check the use of filter cloth and prepare to replace or clean it. The residual oil on the filter cloth should be separated and recovered by centrifugation.
(7) Remaining oil recovery uses an oil-water separation tank to separate the recovered oil and then purify it. Fold the filter cloth with residual oil neatly and evenly and put it into the centrifuge. After separation, the residual oil is recovered and refined again. When operating a centrifuge, the speed of the centrifuge must be strictly controlled and gradually increased from slow to fast when starting. If it is necessary to stop during rotation, the motor should be stopped, but when the centrifuge is not completely stationary, it is not allowed to shut down and continue to start.
