Water separator

Dean-Stark apparatus for separating water from a reaction gas. Bottom left (2) the reaction vessel, bottom right (10) the water collecting vessel.

A water separator is a technical device used to separate water from gas mixtures , aerosols ( mist ) or suspensions .

For example, water separators that work according to a mechanical separation process are built into compressed air systems or fuel systems. The drainage of the water separator, i.e. the removal of the collected water, can be done manually or automatically. Mechanical water separators are also known as sediments.

They were invented in 1920 by Ernest Woodward Dean and David Dewey Stark while they were determining the water content of crude oil samples at the research station of the Pittsburgh Bureau of Mines.

Laboratory scale

chemistry

In chemistry, a water separator is a glass device that is used for azeotropic distillation (entrainer distillation ) and enables the continuous phase separation between entrainer and water. The reaction mixture (1) is heated to reflux and evaporated (2). Similar to a Vigreux distillation, additional trays can be added (3) to improve the purity. The boiling temperature of the azeotrope is monitored by means of a thermometer (4) (4) and it condenses again on the cooler (5). Due to the condensation , the water phase separates from the organic phase and can be collected (9) and measured (10). Since water generally has a higher density than the organic solvent used, it sinks to the bottom while the excess solvent flows back into the flask (1). If this is not the case ( dichloromethane as solvent), an inverse water separator must be used. This process is often used to continuously remove water from a reaction and thereby shift the equilibrium in favor of the product (e.g. in the case of esterifications ).

Popular entrainers for this are toluene or cyclohexane . Information on binary mixtures, their composition and boiling points can be found in databases.

Individual evidence

1. ↑ Derek Lowe, Das Chemiebuch, Librero 2017, p. 266
2. ↑ Organikum , Wiley-VCH Verlag GmbH, 23rd edition, 2009, pp. 57-58, ISBN 978-3-527-32292-3 .
3. ↑ Egon Fanghänel, Joachim Eick, Helmut Hartung, Ernst-Gottfried Jäger, Manfred Lorenz, Wolfgang Schneider, Karl Schöne, Klaus Unverferth, Gert Wolf: Introduction to Laboratory Practice , 4th unchanged edition, VEB Deutscher Verlag für Grundstofftindustrie, Leipzig, 1986, Pp. 259-260, ISBN 3-342-00057-0 .
4. ↑ Azeotrope database , the ratios are mol% (not mass percent).