Search results
Results from the WOW.Com Content Network
Pressure-swing distillation is essentially the same as the unidirectional distillation used to break azeotropic mixtures, but here both positive and negative pressures may be employed. This improves the selectivity of the distillation and allows a chemist to optimize distillation by avoiding extremes of pressure and temperature that waste energy.
A process of heating oil shale to produce shale oil, oil shale gas, and spent shale is commonly called retorting. Airtight vessels to apply pressure as well as heat are called autoclaves . In the food industry , pressure cookers are often referred to as "retorts", meaning " canning retorts" for sterilization under high temperature (116–130 °C).
Vacuum distillation A Kugelrohr ( German for "ball tube") is a short-path vacuum distillation apparatus [ 1 ] : 150 typically used to distill relatively small amounts of compounds with high boiling points (usually greater than 300 °C) under greatly reduced pressure.
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.
However, ordinary distillation below the boiling point is not practical because a layer of vapor-rich air would form over the liquid, and evaporation would stop as soon as the partial pressure of the vapor in that layer reached the vapor pressure. The vapor would then flow to the condenser only by diffusion, which is an extremely slow process.
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.
A McCabe–Thiele diagram for the distillation of a binary (two-component) feed is constructed using the vapor-liquid equilibrium (VLE) data—which is how vapor is concentrated when in contact with its liquid form—for the component with the lower boiling point. Figure 1: Typical McCabe–Thiele diagram for distillation of a binary feed
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.