De-oiling of Raw Lecithin by High Pressure Extraction ... - ISSF 2012

Solubility measurements were performed in a pressure range up to 600 bar and at temperatures of 40°C and 60°C.
Results are presented in Figure 2.
P (bar)
700
600
500
400
300
200
100
40°C 60°C
0
0 10 20 30 40 50 60 70 80 90 100
wt.% CO2
Figure 2: Phase diagram for the system raw lecithin (50% phospholipids)/CO2
Influence of pressure, temperature and stirring rate on:
• distribution of liquid and gaseous phases – possible phase inversions,
• qualitative evaluation of viscosity of mixtures,
• separation of phases after intensive stirring,
was observed.
In the range of applied pressure and temperature (up to 520 bar at 62°C and 700 bar at 40°C) the distribution of
phases was such that the phospholipids rich phase (liquid phase) was the bottom phase and the CO2 rich phase
containing dissolved oil (gaseous phase) was the upper phase.
Lab-scale extraction experiments
Tests were carried out in a 10 litre laboratory scale plant at 400 bar and 500 bar at a constant temperature of
60 °C. The specific CO2 flow rate, which is defined as kilogram of CO2 per kilogram of raw material, was varied
between 75 and 225 kg/kg and it is shown in Figure 3. As could be seen from Figure 3 the phospholipids content
in the de-oiled product is widely independent from the specific CO2-demand at the tested condition.
AIM [%]
100
90
80
70
60
50
40
30
20
10
0
0 50 100 150 200 250
Spec. CO2 [kg/kg]
Figure 3: Phospholipids content (AIM) vs. specific CO2 flow rate
Pilot scale extraction experiments
The tests were carried out at 400 bar and 60 °C with specific CO2 flow rates ranging from 100 kg/kg to 200
kg/kg. During each test run totally 200 kg of raw lecithin were extracted resulting in approx. 100 kg of
powderous de-oiled lecithin. As it was found out during the lab-scale tests, also the pilot scale up tests shows that
the de oiling efficiency is independent from the specific CO2 flow rate in the range between 100 kg/kg and 200
kg/kg.