10 Dec 2024
At Amar we sell both Stirred Pressure Reactors (often used in batch mode) as well as flow reactors for continuous synthesis. Many of our clients are currently converting some of their batch processes to flow mode. This can be for several reasons, e.g. yields, Capex etc. but we find that increasingly process safety is a major driving force. We explore this motivation in this blog post.
To motivate this post we start with an excellent video from the US Chemical Safety Board showing some reactive hazards and explosions that resulted from them: https://youtu.be/sRuz9bzBrtY?si=Gm6nSJv4yQfGtzdT
A common theme in such accidents is that often large batch storage or reactors are involved. Ask yourself: “Had the company in this accident adopted flow chemistry, would the accident have been more or less tragic?”
Chemical reactions can be a very tricky beast. In spite of the best efforts and all our precautions, accidents happen. The crucial question is, even if an accident were to happen what is the catastrophe potential. One challenge in batch processing is that often very large inventories of chemicals are present in the reactor. When these are toxic or flammable even a small incident can then snowball into a major tragedy.
One way out of this dilemma, is to consider flow chemistry. Flow reactors often can be made much smaller than a batch reactor. This is especially true for plug flow patterns (see the image below).
As a result, even if an accident happens, the results stay small, since it is easily contained. Consider this: If something must blow up would you rather that it is a 20,000 Litres batch reactor or a flow reactor of a few litres or a few 100 Litres.
Of course, there’s no magic and things are not always simple. But often process intensification allows higher T and P to be used in flow mode. Reactions become faster and hence residence times smaller. This allows smaller overall volumes to be used. Stay tuned for Part 2 of this blog post for a more detailed evaluation of why flow mode can lead to smaller, safer reactors.
Of course, we do realize that Batch processes will never go away. But it motivates us to reconsider flow mode operations for those classes of reactions where doing so would reduce our risk levels. Talk to our team at Amar for a confidential discussion of your chemistry! [email protected]
