This is a typical glass lined vessel with product residue left on all of its inner surfaces, including the underside of the top head, up into the nozzles and on the stirrer shaft and baffles.
Because of its design a reactor is not easy to clean efficiently due to the many internal obstructions, Stirrer Shafts, Baffles, Level Transmitter & Dip Tubes all contrive to make it a difficult item to clean.
WHAT ARE THE CURRENT METHODS?
- Boil Out or Reflux method.
This involves multiple so lvent charges and transfers and it relies on the vapours from the heated solvent rising into all of the upper areas, with sufficient amounts condensing on the product residue or ‘soil’ and dissolving it. - Fill & Flush.
This method is even less efficient but it can be used for vessels that have no heating jacket, but it does not clean the top head at all. - CIP Using Spray Balls.
The objective of these fixed position heads is to spray solvent evenly around the top of the vessel, so that it wets the top head thoroughly and then “sheets” uniformly down the side walls. But this is not always easy to achieve given current reactor designs, and this system is not something that can easily be retro fitted.
THE MAIN PROBLEM WITH ALL OF THESE METHODS IS THAT THEY RELY TOTALLY ON THE RESIDUE BEING SOLUBLE IN THE SOLVENT THAT IS BEING USED AS A CLEANING AGENT.
To achieve this solubility, the vapour has to reach the soiled areas in sufficient quantities to effectively wet and dissolve the soil, often taking many attempts to reach a satisfactory result.
They use vast quantities of cleaning fluids that are costly to dispose of – the process can take days or even weeks to achieve an acceptable clean.