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Vacuum distillation or distillation under reduced pressure is a type of distillation performed under reduced pressure, which allows the purification of compounds not readily distilled at ambient pressures or simply to save time or energy. This technique separates compounds based on differences in their boiling points.
A simple short path vacuum distillation apparatus can be used for bulb-to-bulb distillation. 1: Still pot with stirrer bar/anti-bumping granules 2: Cold finger - Condenser with maximum surface to condense most of the vapour. 3: Cooling water outlet 4: cooling water inlet 5: Vacuum Adapter 6: Receiving Flask.
The pulled-out cylinders in Fig. 2 show now a different situation regarding the level of the water column. Due to the higher vapor pressure at 50°C, in the hot water column the Atmospheric pressure is capable to elevate the hot water column about 877 cm. In the remaining space, the water starts to evaporate at a pressure of 123 mbar.
Molecular distillation is vacuum distillation below the pressure of 0.01 torr. 0.01 torr is one order of magnitude above high vacuum, where fluids are in the free molecular flow regime, i.e., the mean free path of molecules is comparable to the size of the equipment. The gaseous phase no longer exerts significant pressure on the substance to be ...
The pressure at the top is maintained at 1.2–1.5 atm [2] so that the distillation can be carried out at close to atmospheric pressure, and therefore it is known as the atmospheric distillation column. [3] The vapors from the top of the column are a mixture of hydrocarbon gases and naphtha, at a temperature of 120 °C–130 °C.
The system uses vacuum pumps to create a low pressure, low-temperature environment in which water evaporates even at a temperature difference of 8 °C (14 °F) between two volumes of water. Cooling water is supplied from deep sea depths of as much as 600 metres (2,000 ft).
The compression ratio in a MVR unit does not usually exceed 1.8. At a compression ratio of 1.8, if the evaporation is performed at atmospheric pressure (0.101 MPa), the condensation pressure after compression will be 0.101 x 1.8 = 0.1818 [MPa]. At this pressure, the condensation temperature of the water vapor at the heat exchanger will be 390 K.
A Perkin triangle is a specialized apparatus for the distillation of air-sensitive materials. Some compounds have high boiling points and are sensitive to air. A simple vacuum distillation system can be used, whereby the vacuum is replaced with an inert gas after the distillation is complete. However, this is a less satisfactory system if one ...