KiloMentor Stresses the Importance of the Integrity of the Reactor at Scale

Laboratory equipment costs just a minuscule fraction of that of process equipment. For that reason, scientists can perform a reaction that requires strong aqueous alkali in a glass round-bottomed flask even though one knows that at the end of the reaction the flask will be opaque and etched by the dissolution of a portion of the glass itself. One the other hand, precautions must be taken that a large scale reactor, that is expected to have a long useful life should nor e partially dissolved or pitted or weakened by any reactor contents. A process development chemist must never put a large scale reactor at risk. Consideration should be paid early on that reaction conditions are not incompatible with the materials of construction. Engineers are particularly knowledgable in this area and can provide an early warning that particular conditions must be vetted. This is normally done in the laboratory by placing weighed tiles of reactor surface material into the laboratory reactor throughout the process step of concern and at its conclusion, these tiles are fished out and carefully reweighed. Any experimentally significant difference between before and after weighings is suggestive that teethe reaction conditions are eroding the reactor surface material, 

At the same time, the experiment will detect any unexpected effect of the reactor’s material on the course of the process's reaction.

Loss of the surface of the reactor can also be caused by abrasion. The surface is simply rubbed off and probably remains as fine insoluble particles inside the reactor. Very little can be done about this except togged away from the abrasive reagent. Sometimes this problem can be solved by packing the abrasive agent tightly into a special column-shaped reactor tube and rapidly circulating the reaction mixture solution through the column past the insoluble abrasive agent.

Loss of the reactor surface may simply be caused by excessive pH and this cane controlled by an adjustment in the reactor material itself.

Another cause is the use of or the creation of a very strong chelating agent which simply rips metal ions out of the reactor surface. I have encountered such a situation. I was able to overcome the corrosion simply by adding a stoichiometric quantity of an inorganic iron salt into the reactor with the rest of the reagents. As the chelator formed it complexed the iron cations and left the reactor alone!