The pipeline described in Problem 6.7.1 is used to batch ANS crude along with a light crude (0.85 specific gravity and 15 cSt viscosity at 60°F). Determine the optimum batch sizes to reduce pumping costs based on a 30 day operation. Consider a flow rate of 6000 bbl/hr.
Problem 6.7.1
A pipeline 150 miles long from Beaumont pump station to a tank farm at Glendale is used to transport Alaskan North Slope crude oil (ANS crude). The pipe is 20 in. in outside diameter and constructed of X-52 steel. It is desired to operate the system at ANSI 600 pressure level (1440 psi). The pipeline profile is such that there are two peaks located between Beaumont and Glendale. The first peak occurs at milepost 65.0 at an elevation of 1500 ft. The second peak is located at milepost 110.0 at an elevation of 2500 ft. Beaumont has an elevation of 350 ft and Glendale is situated at an elevation of 650 ft. During the initial phase of operation, 6000 bbl/hr of ANS crude will be pumped at a temperature of 60°F and delivered to Glendale tankage at a pressure of 30 psi. The specific gravity and viscosity of ANS crude at 60°F may be assumed to be 0.895 and 43 cSt respectively.
(a) Determine the minimum wall thickness required to operate the pipeline system at a pressure of 1400 psi.
(b) At a flow rate of 6000 bbl/hr, how many pump stations would be required?
(c) During the second phase it is planned to expand the capacity of pipeline to 9000 bbl/hr. How many additional pump stations would be required? (d) Assuming 80% pump efficiency, calculate the total pumping HP required during the initial phase and under the expansion scenario. Use a minimum suction pressure of 50 psi at each pump station.
