Let us assume that the main objective for the calculations is to
determine the pressure drop in a vacuum type dilute phase
pneumatic conveying system conveying polyethylene pellets at
10,000 lbs/hr rate through a proposed conveying line. Assume
that the line diameter is 4 inch but that it can be changed if the
calculated pressure drop does not fall within the vacuum rating
of the conveying blower. Conveying system uses ambient air at
standard conditions. Starting from the inlet, the conveying line is
80 feet horizontal, then has a 90 degree long radius bend, then
a 40 feet vertical section, then a 90 degree long radius bend,
then a 40 feet horizontal section, then a 90 degree horizontal
bend, and lastly 10 feet of horizontal pipe. Pipeline is internally
scored to prevent streamers. Conveying line material is aluminum.
Ambient conditions are 14.7 psia and 25 C. Air density
at these conditions is 0.075 lbs/cu ft. Pick-up velocity is 65
ft/sec. Solids velocity is 80% of gas velocity. Solids friction factor
is 1.2. Pipeline roughness factor is 0.0005.