Conducting Surge Analysis for 3.5 Km Long Propane/Butane Cross Country Pipeline

The Indian Oil Corporation Ltd LPG Terminal in Kochi has been proposed for the supply of Propane and Butane for supplementing indigenous availability of LPG and meeting demand in the southern states of India. IOCL has proposed to complete its commissioning in two phases (Phase I & II).

In Phase I, it is proposed to utilize the ship heating facility to heat the refrigerated propane and butane. After heating within the ship, propane will be unloaded at a temperature of (-) 2 to 0°C and butane at temperature of (-) 5 to 2 °C which will be directly blended in the blending system at the jetty area to produce LPG. The produced LPG will then be dispatched through the KSPPL Pipeline.

In Phase II, refrigerated Butane and Propane will be unloaded from the ship at temperatures (-) 4 °C and (-) 42 °C respectively and will get heated to 15 °C using heaters at Jetty area and subsequently transferred to the terminal location for storing in pressurized condition. Propane and Butane will be blended in the blending system at terminal area to produce LPG. The produced LPG will be dispatched via tank trucks.

The pipeline system to be investigated consists of the 20” pipeline, pumps and valves.

iFluids Engineering has been entrusted by IOCL to carry out a Surge Analysis Study on the 20” pipeline system, ~ 3.5 km underground LPG cross-country pipeline from the jetty at CPT, Kochi to the LPG Terminal of IOCL at Puthu Vypin.

The Surge Analysis study objectives were conducted in the following manner:

  1. Pipeline modelling:

The pipeline system from jetty to terminal is modelled in a fluid flow analysis software based on the provided layout and relevant drawing documents. Separate models for PHASE-I & PHASE-II is prepared.

  • Steady state analysis:

Steady state analysis is conducted to verify the operating capacities and scenarios for specified boundary conditions in PHASE-I and PHASE-II model. The analysis results provide the initial conditions for transient analysis.

  1. Transient state analysis:

Transient analysis for PHASE-I & PHASE-II is conducted using the steady states results to check if any surge relief mechanism is required. Surge pressure in each scenario with different system variables like valve closure time, type of valve is checked.

  • Recommendations:

If surge mechanisms are required, they are recommended and verified in simulation.

The Study outcome and recommendations were later implemented by IOCL on their cross country Pipeline system.