Falling Film Reactor for Gas-Liquid Reactions

Microstructured Falling Film Reactor for Gas-Liquid Reactions 

The fading film MSR is one of the most commonly used devices for gas-liquid reactions (examples are given in gas-liquid reactions section). The liquid flows downward because of gravity in the form of film and gas flows through the open space that lies in the top cover of the housing. The falling film contactor consists in general of a stainless steel plate with open channels, typically 300 pm deep, separated by about 100 pm thick walls. The role of open microchannels is to prevent the breakup of the liquid film. 

Because of capillary force and small channels width, surface wetting liquids are pulled along the walls, thus forming a flowing meniscus. With increasing flow rate, the thickness of the film increases and its surface becomes flatter. 

The specific gas-liquid interfacial area can attain up to 20 000 m m , which is 2-3 orders of magnitude larger than conventional bubble columns and agitated vessels (200 m m ). 

The main drawback of the microstructured falling film reactor is the short residence time of the liquid in the channels, which typically varies between 5 and 20 s, depending on physical properties of the liquid and the operating conditions. The residence time can be increased by lengthening the microchannel or by decreasing the angle of descent, which can be achieved by helicoidal microchannel falling 

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