SPM-3900 Liquid Pipeline

Process Description

Pipelines are used to transport liquids such as water, crude oil, fuels and bulk petrochemicals from supply sources over long distances to users of the fluid. In SPM-3900, the pipeline liquid is water and is supplied from two sources at the beginning of the pipeline system. The flow rate and pressure of each supplier is variable and not under direct control of the pipeline operator except by isolation using an emergency shutdown switch.

The supply liquid is transported over a long pipeline segment to Booster Pump Station No. 1 in order to increase the pressure of the liquid so it will continue flowing through the next pipeline segment. The booster pumps are configured in series, but only one can be operated at a time. Bypass lines with check valves ensure flow automatically continues around any stopped pump. The electric motor of each pump is served by a common variable frequency drive (VFD) which modifies the electrical line voltage characteristics which therefore changes the speed of the motor. The VFD “speed” is modulated by a system of multiple process controllers to regulate either the suction pressure of the pump station, the discharge pressure of the pump station or the total electricity consumed by the pumps. A selector circuit ensures the controller closest to its setpoint is in control of the VFD “speed”. The operator can adjust the setpoint of each of these controllers to keep pipeline pressures from getting too high or low and to prevent excessive electricity consumption.

Booster Pump Station No. 1 can be bypassed in case the pump station needs to be isolated for maintenance. Interlock logic prevents bypassing the station unless no pumps are operating. The pump station includes equipment to filter out any solid particulates before pumping.

The liquid pipeline system contains two more pump stations which operate identically to Booster Pump Station No. 1. Each pump station is separated by very long pipeline segments. Users take flow off the pipeline downstream of Pump Stations No. 1 and 2 under flow control. Like suppliers, the pipeline operator does not have direct control of the flow rate to each user except by isolation using an emergency shutdown switch. The final user takes flow off under pressure control at the end of the last pipeline segment.

Program Features

SPM-3900 is preconfigured with a number of exercises where the pipeline operation is relatively balanced and then supply and/or demand changes over time. The operator will need to assess the situation and determine if a change in the operating pumps, control setpoints or supplier/user isolation is needed to keep the pipeline operating safely.

The following instructor features allow SPM-3900 operating conditions to be set up to reflect typical pipelines if so desired:

  •  Adjustable battery limit conditions
  • Adjustable length and diameter of each pipeline segment
  • Adjustable pump characteristics

Additionally, SPM-3900 is engineered with wide instrument ranges on pressure and flow controllers (flows are set via instructor access) to allow operation at desired process conditions.