Negative pressure oil extraction is very popular in oil production because of its well-known effects of energy saving and good quality crude oil, but with investment and production capacity in mind, we recommend better to adopt the extraction of oil Negative pressure for the extraction of large-capacity edible oil, better not less than 100t / d of edible oil extraction, for a small capacity, it is difficult to show significant energy-saving effects but costs much higher.
The extraction of oil under negative pressure is applied for different extractions of edible oil: extraction of peanut oil, extraction of soybean oil, extraction of palm oil, extraction of mustard oil, etc.
In fact, the extraction of oil under negative pressure mainly refers to evaporation under negative pressure.
This technology is reusing the secondary desolventizer steam as the heat resource for the first evaporation or the second evaporation, because under negative pressure, the boiling point of the mixed oil will be reduced, causing the evaporation temperature to reduce and get to reuse the Secondary steam.
Under normal pressure, the boiling point of mixed oil with a concentration of 50% is more than 80 ℃, the secondary desolventizer steam is about 80-82 ℃, which is not enough for the heat exchange. But under negative pressure, the vacuum at 60-65kPa, the boiling point of the mixed oil is about 60-62 ℃, then it is possible to reuse the secondary desolventizer steam to heat the first evaporation.
♦ Significant effect of energy saving
Using less direct steam and reducing the operating temperature inside the oil plant, resulting in less recycling water consumption, fuel consumption and solvent consumption, etc. compared to normal pressure.
♦ Improved oil quality
Because under negative pressure, the mixed oil keep the low temperature and avoid the oxidized oil, which will get the crude oil lighter color with low solvent residue, help reduce energy consumption in oil refining.
♦ Smallest condensation area
The secondary steam does not go directly to the capacitors under negative pressure, reducing the total amount of heat to be condensed., So for the same capacity, smaller capacitors equipped with normal pressure, which will save on the consumption of cold water and total inversion.