You must transport a sludge product from an open storage tank to a separations unit at 1 atm, through a 4 in. sch 40 steel pipeline that is 2000 ft long, at a rate of 250 gpm. The sludge is 30% solids by weight in water and has a viscosity of 50 cP and Newtonian properties. The solid particles in the sludge have a density of 3.5 g/cm3 . The pipeline contains four gate valves and six elbows.
(a) Determine the pump head (in ft) required to do this job. You can select any pump with the characteristics given in Appendix H, and you must find the combination of motor speed, motor horsepower, and impeller diameter that should be used.
(b) You want to install a long radius venturi meter in the line to monitor the flow rate, and you want the maximum pressure drop to be measured to be equal to or less than 40 in. H2O. What should the diameter of the venturi throat be?
(c) At the separations unit, the sludge is fed to a settling tank. The solids settle in the tank, and the water overflows the top. What should the diameter of the tank be if it is desired to limit the size of the particles in the overflow to 100 m or less?
(d) If the sludge is fed to a centrifuge instead of the settling tank, at what speed (rpm) should the centrifuge operate to achieve the same separation as the settling tank, if the centrifuge dimensions are L ¼ D ¼ 1ft; R1 ¼ R2=2 ¼ 0:25 ft?
(e) Suppose the sludge is fed instead to a rotary drum filter that removes all of the solids from the stream. The drum operates at a vacuum of 6 psi, has dimensions L ¼ D ¼ 4 ft, and operates with 30% of its surface submerged. A lab test is performed on the sludge using 1 ft2 of the same filter medium as on the drum, operating at a vacuum of 500 mmHg. In this test, it is found that 8 gal passes the filter in 2 min, and a total of 20 gal passes through in 10 min. At what speed (rpm) should the rotary drum filter be operated?