Basically, scale-up is the interpretation of the fundamental knowledge of the processing system and the proper prediction of the performance of the process in large-scale operations. Scale up of suspension obligations can be exceptionally intricate. Different scale-up criteria have been proposed considering the sort of suspension required, as talked about prior. Process or item prerequisites can force extra criteria for thought.
Some common complications are as follow:
· Solids with extraordinarily wide particle size distributions — the fine particles have an effect on the suspension of the large particles.
· Very high-solids concentrations — particle interactions have an effect on the apparent rheological properties.
· Presence of little amounts of extremely large particles — not possible to suspend however should be stirred around on the bottom of the vessel
· The presence of significant quantities of very small particles — these primarily behave as a part of the fluid
To accommodate these concerns, solid-suspension duties are typically classified into four broad categories based on the hindered-settling velocity.
· Type I tasks are simple suspending duties that are promptly expected because of the liquid flows around the particles in simple, laminar flow.
· Type II are demanding suspension tasks wherever the fluid flow is a lot of complexes however predictable from empirical correlations — this category covers most of commercial applications.
· Type III is troublesome or “heavy” suspension tasks, that probably involving large or heavy particles. During this category, scale-up is typically based on pilot-scale tests.
· Type IV tasks, a homogenous suspension is no longer possible, as they need very high liquid velocities that can’t be achieved economically.