Pneumatic conveying is a material transportation process in which powders or granular materials are moved over horizontal and vertical distances within a plant premises with the help of air.
Using either the positive or negative pressure of air or other gases, the material to be transported is forced through pipes and finally separated from the carrier air and deposited at the desired destination.
Except ducting, which can be underground or on the walls, there are few other parts to be installed. Saves space, where it matters.
Lean Phase Conveying:
The material to gas ratio is very low in this case. Can be a positive pressure and/or a negative pressure system.
Particle size is an important factor that affects the design of a pneumatic conveying system. But it is not that the smallest particles are the easiest to convey.
Another very important factor that would determine the power requirement of the system.
Deceptively identical materials (with say similar bulk density, particle size, etc.) would behave so differently that a pneumatic conveyor may be a great success with one and might completely fail with the other.
The system is always designed for a particular material flow rate - say tons/hour.
The energy consumed by a pneumatic conveying system is directly proportional to the distance over which the material is conveyed - but the horizontal distance is different from the vertical distance.
Number and type of bends:
A bend consumes much more energy (more so if the radius of bend is small) that a straight duct.