Ammonia oxidation in a microreactor

Continuous or batch?

The microreactor we studied in this project is called a continuous type since the ammonia and oxygen reactants flow through it continuously, but there is another kind of microreactor called a batch microreactor. In a batch microreactor the reactants are pumped into the reactor for a short time only.

A good comparison would be to think about the differences between a camcorder and a Polaroid camera. Like with these two types of cameras, there's a time and place for each type of microreactor. While continuous microreactors are useful for making a product (like nitric oxide), batch microreactors are being designed as the heart of miniaturized medical analyzers. A sample is injected into one end of the microreactor and the analysis results pop out the other, so to speak. A big advantage is that the sample size these analyzers need will be much, much smaller. If you've ever had to have blood drawn for tests, you know what we mean!

One example of a batch microreactor comes from work done at Penn State. They have developed batch reactors with volumes as low as 0.4 picoliter (that's 0.0000000000004 liter). A second example of a batch microreactor is a DNA analyzer being developed at the University of Michigan. Its sample size is not quite as small - 120 nanoliters, or 0.000000120 liter - but that's still pretty darn small.

BUT ...

If you're really interested, check out the junior chemical engineer's version of this page.

If you're sort of lost, here's how to get all the way back to the beginning of the high school version