Essential oil distillation extraction refers to the extraction of essential oil from aromatic plants by steam distillation, which is the most commonly used and cleanest method of extraction of essential oil. The essential oil of 95% aromatic plants can be obtained by distillation.
Aromatic plants are suitable for distillation extraction of flowers, roots, leaves, wood chips.
One. Distillation in water
It is to put the aromatic plant raw materials into the boiler first, then add water or a pot of distilled pure dew, the height of water just over the material layer.Heating methods include direct water steam heating, electric jacket heating, burning gas (liquefied gas and gas) at the bottom of the pot.During the heating of the electric jacket and the direct heat of the bottom of the pot, a screen plate should be set between the materials and the bottom of the pot to prevent the direct contact between the raw materials and the heat source from burning, which will affect the quality of the essential oil.
The raw materials are always submerged in water, and the distillation is more uniform, and the steam short circuit will not be caused by the solidification of the raw materials.Distilled water is suitable for some larger flowers, such as roses;Broken skins and easily bonded raw materials.However, the esters in distilled water can be hydrolyzed easily, so high-ester spice plants cannot use this method.
Water distillation, also known as separation distillation: is the raw material placed in the distillation pot on the screen plate, under the screen plate to contain a certain amount of water to meet the distillation operation required production?Water distillation method schematic diagram enough saturated steam, the water layer height takes the water boiling when does not splash wet raw material bottom as the principle.Water distillation can also be used under direct heating, indirect steam heating, electrical jacket heating.
At the beginning of distillation, the water layer at the bottom of the pot is first heated until boiling. The generated low-pressure saturated steam passes through the upper material layer through the screen plate. The entire process of rising from the saturated steam into the material layer to the top of the pot to form the mixed steam of water and oil is appropriate to proceed slowly, which generally takes about 20-30 minutes（small quantity according to different output and material).The low-pressure saturated steam produced by water distillation is only in contact with steam. Due to the large moisture content, it is beneficial to the evaporation of essential oil, shorten the distillation time, save fuel and improve the oil yield and oil quality.Water distillation is widely used. The aromatic plants grown in large areas are mint, citronella, eucalyptus leaves, etc.This method is also applicable to dry raw materials after crushing, including wood chips and some dried flowers and plants. Dry materials need to be soaked with water before distillation, so that the materials can be soaked thoroughly.
Three. Steam distillation
Steam distillation is direct steam distillation. Steam produced by steam generator or small boiler is distilled directly into the pot.Usually steam is ejected directly under the sieve plate and enters the raw material layer through the sieve hole of the sieve plate to heat the raw material.The steam produced by the steam generator has a certain micro pressure steam, and the pressure of the steam through the small boiler is set within 0.5kg.Saturated steam with higher temperature and lower moisture content can quickly heat the material layer.Therefore, when the dry material is heated and distilled, the dry material must be soaked in advance before filling the pot.Direct steam distillation, its distillation speed is fast, temperature is high, can shorten distillation time, the composition of high boiling point can be steam out, oil yield is high.Direct steam distillation is suitable for fresh or prewetted dry materials such as michelia leaves, orange leaves and cinnamon leaves of smaller volume diameter.
The difference between steam distillation and steam distillation
Water distillation, water distillation, direct steam distillation (water distillation).In distillation, there are mainly three kinds of action, that is, water dispersion, hydrolysis and thermodynamic action.Water distillation is not suitable for easy hydrolysis and thermal decomposition of raw materials.By comparison, hydro-gas distillation has the minimum hydrolysis effect and high efficiency, but its equipment conditions are higher, and it needs attached boiler to facilitate mass production.