Optimization of Pipeline Pressure Control

Industry

Refining

Business Issue

End Customer demand required additional capacity requirements beyond the current system capabilities.  The current system historically was experiencing pressure oscillations and line upsets that limited the capacity.  The client was looking to increase the throughput capacity through optimization of the pressure control system including control strategy modifications as well as pressure control valve analysis and maintenance.  .

Project Summary

The project included an initial assessment of key delivery and inline pumping stations to assess the overall control scheme, transmitters and the control loops associated with the control valves.  This analysis included a review of the valve condition and performance.  A maintenance plan was put together for the remaining 21 control valves based on these findings. 

In addition, a performance analysis was performed on the pressure control system. The control performance analysis and evaluation quantified variability, stability, and response behavior to set point changes and disturbances, and optimized the PID tuning parameters. The optimization of the system was then performed on the equipment to obtain superior performance and responsive and robust control over a broad range of flow rates and product types.

Valve and actuator training was also conducted for the client’s maintenance staff to provide better preventative maintenance and repair of the valves.

Scope Responsibility

Cornerstone Controls’ scope of work on the project included:

  • Equipment assessment including:
    • FlowScanner Diagnostic Services on the control valves
    • Equipment assessment report providing baseline information for predictive maintenance, minor required adjustments, and recommendations to optimize performance
  • Process control consulting
    • As-Found control performance evaluation
    • Detailed Analysis of the system including:
      • Identification of loop and station interaction
      • Identification of process dynamics in the station loops along the pipeline
      • Review of the pressure and flow transmitters
      • Review of the stability at higher flow rates
        • Analysis of pressure cycling
      • Implementation and validation of the recommended tuning sets from the simulation
      • Closed loop testing to evaluate the new performance improvement
      • Measuring the as-left variability

Results

  • Intermediate stations are now reliably operated with both pump units simultaneously engaged
  • A pipeline sustained capacity increase of a minimum of 3.5% has been directly attributed by the customer to the pressure control optimization efforts
  • Substantial annual cost savings in pumping energy savings were achieved through PCV pressure drop reductions at most mainline pump stations
  • At one delivery site, a 32% reduction in delivered batch size over / short volumes was achieved
  • Operators report a significant increase in pipeline reliability, with historical data indicating a 50% reduction in one indicator of 'operator burden'