[25 marks overall] A coal-water slurry containing 65 -wt % coal is pumped at a rate of 15 gpm from a storage tank through a 164ft long 1/2-in. sch. 40 pipeline to a boiler where it is burned. The storage tank is at 1 atm. pressure, and the slurry must be fed to the burner at 20psig. The specific gravity of the coal is 2.5 . The slurry is non-Newtonian and behaves as a Bingham plastic, with a yield stress of 80Pa and a plastic viscosity of 200cP. If the pump is 78% efficient, what size pump is needed? f=0.0312;WS=4680m2s2;WP12.5hP