Search results
Results From The WOW.Com Content Network
The diagram shows a typical reflux apparatus. It includes a water bath to indirectly heat the mixture. As many solvents used are flammable, direct heating with a Bunsen burner is not generally suitable, and alternatives such as a water bath, oil bath, sand bath, electric hot plate or heating mantle are employed. [6]
The McCabe–Thiele method is a technique that is commonly employed in the field of chemical engineering to model the separation of two substances by a distillation column. [ 1 ] [ 2 ] [ 3 ] It uses the fact that the composition at each theoretical tray is completely determined by the mole fraction of one of the two components.
A balance of heating with a reboiler at the bottom of a column and cooling by condensed reflux at the top of the column maintains a temperature gradient (or gradual temperature difference) along the height of the column to provide good conditions for fractionating the feed mixture. Reflux flows at the middle of the tower are called pumparounds.
The solvent is heated to reflux. The solvent vapour travels up a distillation arm, and floods into the chamber housing the thimble of solid. The condenser ensures that any solvent vapour cools, and drips back down into the chamber housing the solid material. The chamber containing the solid material slowly fills with warm solvent.
Like vacuum distillation, steam distillation is a method for distilling compounds which are heat-sensitive. [ 1 ] : 151–153 The temperature of the steam is easier to control than the surface of a heating element and allows a high rate of heat transfer without heating at a very high temperature.
Temperature vs. heat load diagram of hot stream (H 2 O entering at 20 bar, 473.15 K, and 4 kg/s) and cold stream (R-11 entering at 18 bar, 303.15 K, and 5 kg/s) in a counter-flow heat exchanger. "Pinch" is the point of closest approach between the hot and cold streams in the T vs. H diagram.
Heat reflux extraction; ... "Essential guides to method development in solid-phase extraction," in ... Text is available under the Creative Commons Attribution ...
The amount of heat entering the column from the reboiler and with the feed must equal the amount heat removed by the overhead condenser and with the products. The heat entering a distillation column is a crucial operating parameter, addition of excess or insufficient heat to the column can lead to foaming, weeping, entrainment, or flooding.