Put the fresh citrus peel into the press, and use pressure to crush the oil sac cells on the citrus exocarp to make the essential oil seep out, and spray it with water, then separate and refine to obtain the cold-pressed essential oil. The process is as follows:
(1) Selection and crushing of citrus peels
For the cold pressing method, fresh and mildew-free citrus peels should be selected, and the sediment and sundries should be removed first, and then washed with water. Because the essential oils of different types of citrus peels are different, they can be classified according to citrus peel, orange peel, orange peel, and pomelo peel. If possible, the mesocarp (white layer) of orange peel and pomelo peel should be removed as much as possible to prevent it from absorbing the extracted essential oil. Crush the cleaned citrus peels into 4-5mm pieces with a crushing machine for later use.
Pressing is preferably carried out in a screw press. After the material is put into the press from the feeding port, under the push and extrusion of the screw propulsion rod, the oil sac cells on the exocarp are squeezed and crushed, and the essential oil seeps out from it, and is sprayed with an appropriate amount of water from the press. flow out. The amount of spray water should not be too much, too much water will increase the burden of subsequent treatment; it should not be too little, too little, and the squeezed essential oil cannot be completely flushed out of the press. The operation should be mastered according to the actual situation. The pomace from the press is retained for subsequent extraction of other ingredients.
The peel juice from the squeezer can be filtered immediately into the filter to remove the residue from the peel juice. The filtered peel juice is placed in a settling tank for oil-water separation, and the filter residue is combined with the pressed residue for subsequent extraction of other components.
(4) Oil-water separation
Settling tanks can be continuous or intermittent. Continuous settling tank. The filtered peel juice liquid enters the settling tank from the middle of the settling tank, and the essential oil and water are gradually separated in the settling tank to form an oil layer and a water layer. The clarified essential oil overflows from the upper part of the settling tank, and the water is drawn from the lower part of the settling tank. By adjusting the height of the water outlet of the water outlet pipe, the height of the oil-water interface in the settling tank can be adjusted.
If an intermittent settling tank is used, fill the settling tank for each concentration and let it stand for a period of time to slowly release the oil and water.
(5) Stand still
Since the crude essential oil obtained by oil-water separation is also entrained with a small amount of water and possible peel wax, it needs further standing treatment. The most commonly used simple method is to stand the crude essential oil at a low temperature of 5-8°C for 5-6 days, most of the residual water will settle out, and the peel wax in the essential oil will also crystallize at low temperature. The water and wax precipitated at the bottom are released, and the upper essential oil flows through a column filled with anhydrous calcium chloride to further remove possible residual moisture to obtain the Citrus Essential Oil product.