Continuous Manufacturing / Process Intensification is a hotly discussed topic in academic circles for the last decade, yet adoption of Continuous processes to the industry has not been as fast as we would have wished it to be. At Amar we encounter PI questions all the time and thought it would be apt to cover some of the common questions and misconceptions as a blog post as a set of FAQs. We are trying to make the questions particularly applicable to fine chemicals This is Part 2 of the Blog Post on this topic:
- How are continuous reactors different from microreactors?
Microreactors refer to the dimensions of a reactor whereas continuous is a flow mode. Typically all Microreactors are continuous (but not always!) however the opposite does not apply: e.g. The petrochemicals or refining industry uses continuous reactors of large dimensions that can hardly be called microreactors! For example the image below shows part of a large FCC unit in a refinery. This is continuous but definitely NOT a microreactor!
- When do microreactors make sense for a chemical project?
Microreactors can be a fit for several niche situations. E.g. Highly exothermic reactions where even a larger continuous reactor may not have enough surface area to remove heat. (Note that the Amar 3D printed reactors [see image below] are an excellent solution to reactions of this type!) Frequently these are extremely fast reactions e.g. Grignard chemistries, tert Butyl Lithium etc. Another area is lab chemistry where demonstrating a route or total synthesis is of interest but not really scaling to hundreds of kilos or production. A third situation is for screening catalysts, massively parallel reaction optimization or measuring kinetic data.
MicroFLO Reactor
- When do microreactors NOT make sense for a chemical project?
Typically for low price per kilo & high tonnage products microreactors will not make sense. Remember that microreactors may have great heat and mass transfer but they also have high Capex. Number Up typically does not have the Capex saving advantages of scale up.
- How can I reliably scale up a process from lab to pilot to production?
There is no magic answer for this. One way is to use good old chemical engineering. Another is to choose a vendor that can manufacture larger equipment so that the same design is available in larger sizes. As far as possible geometric and kinematic similarity should be maintained between equipment at various scales. We realize this may not always be possible but one should not try to switch to very different form factors.
- Can continuous reactors be used for Pharma for FDA controlled reactions?
For the last 5+ years the FDA is very supportive of continuous manufacturing. There are different concepts of how to define batches, how to deal with off-spec material, CIP between campaigns etc. It is a myth that Pharma cannot use continuous processes. It very well can. Just talk to a vendor who understands GMP and consult the excellent guidelines produced by US-FDA for continuous API processes!
We hope that some of these tips help in your transition from Batch to Continuous processes. Do always contact our team at Amar for a no-obligation discussion of your particular needs.
