A Bell & Gossett Series e-1531 model 5BD pump operating at 1770 rpm is being used to deliver 250 m3/h of a 10% methanol solution at 5°C through a pipe network.
The impeller diameter is 8.5 inches. The pipe is class 300 sch 40 commercial steel. The pump and other fittings, valves and hardware for the pipe network cost 6.5 times the amortized pipe cost per ft. The pump runs 16 hr/day for 200 days each year. Annual maintenance is estimated to be 2% of the amortized installed pipe costs per ft. The cost of energy is $0.12/kW-h. The pipeline is expected to have a 35-year life and a rate of return of 16%. Inflation costs are estimated to be 2.5%. The system was installed in 2017. Determine:

a. The economic diameter (m)

b. The economic velocity of the fluid (m/s)

c. Specify a pipe that best suits this application (specify nominal diameter).