Fractionating Geranium Essential Oil

The fractionating geranium essential oil using a fractionation column is to utilize the differences in boiling points of various components in the essential oil (such as geraniol, citronellol, and citral) to achieve separation and purification, thereby improving the aroma purity and quality of the essential oil.

Key Operational Points:

1. Raw Material Pretreatment: Crude geranium essential oil (obtained through distillation) is dehydrated and dewaxed to prevent scaling inside the column;

2. arameters: Vacuum distillation is used (to lower the boiling point and prevent oxidation of heat-sensitive components), with a column top temperature of 60-90℃, a pressure of 5-15 kPa, and a reflux ratio of 2-5;

3. Fractional Collection: The distillate is collected in segments based on the distillation temperature, prioritizing the collection of the middle fraction containing high-aroma components (mainly geraniol and citronellol).

Geranium Essential Oil Fractionation Column Operation Steps Checklist

I. Preparation Before Fractionating

1. Raw Material Pretreatment: Take crude geranium essential oil (obtained by steam distillation), add anhydrous sodium sulfate (5%-8% by weight of crude oil), let stand for 2-4 hours to dehydrate, filter to remove the desiccant; refrigerate at low temperature (0-5℃) for 2 hours, filter to dewax, and obtain refined crude oil.

2. Equipment Inspection: Check the sealing of the distillation column (packed column/sieve tray column), condenser, receiver, vacuum pump, and temperature control system to ensure no air leakage; fill with inert packing (such as glass beads, stainless steel mesh) to ensure uniform gas-liquid contact.

3. System Commissioning: Start the vacuum pump and evacuate the system pressure to 5-15 kPa (adjust according to composition), stabilize for 30 minutes; commission the temperature control system to ensure accurate temperature display at the top and bottom of the column.

II. Operation Procedure

1. Feed: Inject the pretreated crude oil into the reboiler through the feed inlet, filling the reboiler to 1/2-2/3 of its volume. Close the feed valve.

2. Heating Start-up: Slowly heat the reboiler at a rate of 5-8°C/h to avoid localized overheating and oxidation of components; simultaneously maintain the vacuum pump running to keep the system under reduced pressure.

3. Establishing Reflux: When distillate appears at the top of the column, close the receiver valve and open the reflux valve, controlling the reflux ratio at 2-5 (adjust according to aroma requirements). Stabilize the reflux for 30-60 minutes to allow the gas-liquid mixture in the column to reach equilibrium. 4. Fractional Distillation:

First Fraction (Head Distillate):Collected when the column top temperature is below 60℃. Mainly contains low-boiling-point impurities (such as small amounts of water and light hydrocarbons). Discard or collect separately (relatively weak aroma).

Middle Fraction (Middle Section):Collected when the column top temperature is 60-85℃. Mainly contains high-aroma components such as geraniol and citronellol, representing the target essential oil (rich and pure aroma). Collect separately.

Final Fraction (Tail Distillate): Collected when the column top temperature is 85-90℃. Contains high-boiling-point heavy components with a more complex aroma. Can be collected separately or reused in the next distillation batch.

5. Process Monitoring: Record the column top/bottom temperature, system pressure, and reflux ratio in real time. Take samples every 30 minutes to smell the aroma and adjust the collection rate (to avoid incomplete separation due to excessively rapid distillation).

III. Post-Distillation Finishing

1. Shutdown: After the main fraction has been collected, stop heating, keep the vacuum pump running, and shut down the vacuum pump after the column temperature drops to room temperature. 2. Equipment Cleaning: Rinse the tower, condenser, and pipes with anhydrous ethanol to remove residual essential oil. After drying, seal to prevent contamination.

3. Product Storage: After filtering the main distillate essential oil, store it in brown glass bottles, seal, and store in a cool, dry place (away from light and high temperatures). Test the aroma and purity before warehousing.

IV. Precautions

1. Maintain reduced pressure throughout the process to prevent the oxidation and decomposition of heat-sensitive aroma components (such as citral), which would affect the quality of the essential oil.

2. A reflux ratio that is too small will result in poor separation, while a reflux ratio that is too large will reduce production efficiency. Adjustments should be made flexibly according to the purity of the crude oil.

3. Take protective measures during operation to avoid skin contact with essential oil (which may cause allergies). Open flames are strictly prohibited in the equipment area (essential oils are flammable).