Blower & Vacuum Best Practices, April 2017, by Roger E. Blanton.
http://www.blowervacuumbestpractices.com/industries/conveying/heart-pneumatic-conveying-systems-%E2%80%93-positive-displacement-blower-calculations

"The heart of the pneumatic conveying system (air mover, solids feeder, pipeline, and separator) is the air mover. Correctly specifying the volumetric flow rate and pressure levels required to move the material will determine system reliability.  One must also look at pipe size, distance, and the weight of the material being moved. A company specializing in the design requirements of pneumatic conveying systems is best consulted for evaluating these requirements and specifying the required air or gas flow rate for the system."