Accurate dosing of small organic solvent flows

Solvents are the workhorses within chemistry. They are usually liquids that interact in such a way with solids, gases or other liquids that the latter become dissolved - distributed uniformly on a molecular scale.

Especially organic solvents such as ethanol, acetone, hexane or diethyl ether find their use in many applications. For example as medium in chemical and pharmaceutical syntheses and for extraction, as diluting vehicle in oil-based paints that evaporates when the paint dries, or in nail polish removers.

Within chemical industry, the supply of organic solvents is a frequently occurring operation. In this context, Bronkhorst delivers devices to accurately dose small flows of organic solvent.
 

Process solution

To dose small flows of solvent into a reactor vessel at low pressure, Bronkhorst has a combination of Coriolis mass flow controllers (series mini CORI-FLOW) with a gear pump available for that purpose.

For the current application, the amounts to be dosed are so small that this dosing can't be done with any equipment whatsoever, since most devices on the market are not accurate enough on a small scale. In this case, 'small' means 0.5 to 6 kg/h, or even smaller: 0.1 to 2 kg/h. Both ranges are covered with M14 and mini CORI-FLOWM13 mini CORI-FLOW mass flow controllers, each with a liquid flow valve (type C5I) - to be controlled by client based readout & control equipment. A Tuthill gear pump is used to build up pressure that is necessary for the mass flow controllers. Furthermore, an overflow valve allows for the backflow of excess medium.

To be able to withstand a variety of organic solvents, the parts that are in contact with the medium are made of stainless steel, whereas o-rings can be made of Teflon, Kalrez or PEEK. As the organic solvents may be inflammable, the devices can be ATEX Zone-2 certified.