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  Series Crude Oil Pipeline Stations Using Rotary Positive Displacement Pumps 

The initiating station will have storage tanks/tank farm from which this station draws oil, sometimes via a low pressure boost pump unless the high pressure pumps are in close proximity to the tanks. The most common arrangement uses three 1/2 capacity pumps (one or two running, one a hot spare). This first station pumps the oil to the inlet of the next station. The receiving station has a bypass control valve from station discharge to station inlet. The bypass control valve senses station inlet pressure and bypasses whatever flow is necessary to maintain station inlet pressure at set point, usually 50 to 75 PSIG (3.5 to 5.2 BarG).

Normally, one of the second or subsequent station pumps is started. If station inlet pressure rises above set pressure, a second pump is started and the bypass control valve recirculates whatever volume of oil is necessary to maintain station inlet pressure at set point.

An alternative approach uses a variable speed drive to control pump speed maintaining station inlet pressure at the desired point. Since any combination of pumps could be running at the same time, all of the pumps should be equipped with variable speed drivers.

Regardless of method, each pump needs its own pressure relief valve (not shown below for clarity) connected from pump discharge to pump inlet. Their set pressure needs to be about 8 to 10 percent above normal station discharge pressure.

This entry was posted on Sunday, November 2nd, 2008 at 1:00 pm and is filed under Jim Brennan Blog. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.