Q: Disadvantages of a Pneumatic Conveying System in Comparison to a Mechanical Conveying System?
A: A pneumatic conveying system typically requires far more horsepower to operate than an equivalently sized mechanical conveying system. The reason is that changing the air pressure to achieve pneumatic conveying consumes a large amount of power and is inherently less efficient than a mechanical conveying system’s mechanical transfer. In fact, in applications with the same transfer rate over the same conveying distance, a pneumatic conveying system can require 10 times the horsepower of a mechanical conveying system. A pneumatic conveying system also requires a larger dust collection system than a mechanical conveying system. This is because the pneumatic system has to separate the conveyed material from the conveying air at the system’s end. Some materials have characteristics that make them difficult to convey in a pneumatic system. Examples are a material with a large particle size and high bulk density, such as gravel or rocks, and an extremely sticky material, such as titanium dioxide, which tends to build a coating on any material-contact surface. In a pneumatic conveying system, such buildup often leads to total pipeline blockage. These difficult materials can be easier to transfer in a mechanical conveying system that’s been carefully chosen to handle them.