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Vacuum drying is the mass transfer operation in which the moisture present in a substance, usually a wet solid, is removed by means of creating a vacuum. In chemical processing industries like food processing , pharmacology, agriculture, and textiles, drying is an essential unit operation to remove moisture. [ 1 ]
Dielectric drying (radiofrequency or microwaves being absorbed inside the material) is the focus of intense research nowadays. It may be used to assist air drying or vacuum drying. Researchers have found that microwave finish drying speeds up the otherwise very low drying rate at the end of the classical drying methods.
Drying of solids can be brought about by storing the solid over a drying agent such as phosphorus pentoxide (P 2 O 5) or silica gel, storing in a drying oven/vacuum-drying oven, heating under a high vacuum or in a drying pistol, or to remove trace amounts of water, simply storing the solid in a glove box that has a dry atmosphere.
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 oven with oil pump. In chemistry, a vacuum oven is an oven that can also apply a vacuum to its contents. Such devices are useful for removing solvent or dehydrating samples. They are equivalent to Abderhalden's drying pistol in some ways, but vacuum ovens typically can
A vacuum desiccator (left) and desiccator (right). Silica gel with cobalt chloride indicator placed in the lower shelf is used as the desiccant.. A desiccator is a heavy glass or plastic container, now somewhat antiquated, used in practical chemistry for drying or keeping small amounts of materials very dry.
A vacuum desiccator (left - note the stopcock which allows a vacuum to be applied), and a desiccator (right). The blue silica gel in the space below the platform is used as the desiccant . Desiccators are sealable enclosures containing desiccants used for preserving moisture -sensitive items such as cobalt chloride paper for another use.
In vacuum applications, a cold trap is a device that condenses all vapors except the permanent gases (hydrogen, oxygen, and nitrogen) into a liquid or solid. [ 2 ] [ needs update ] The most common objective is to prevent vapors being evacuated from an experiment from entering a vacuum pump where they would condense and contaminate it.