Case Study

Surge Analysis for Propane and Butane Cross Country Pipeline

Project Overview

iFluids Engineering conducted a Surge Analysis to identify and mitigate pressure surges that could damage the pipeline or equipment. The project’s objective was to ensure the safe and efficient transportation of propane and butane through a 3.5 km underground pipeline.

The pipeline system to be investigated consists of the 20” pipeline, pumps, and valves. iFluids Engineering successfully carried out the 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 Indian Oil Corporation Ltd LPG Terminal in Kochi has been proposed for the supply of Propane and Butane, supplementing indigenous LPG availability 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 was 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 a 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 be heated to 15 °C using heaters at the Jetty area and subsequently transferred to the terminal location for storage in a pressurized condition. Propane and Butane will be blended in the blending system at the terminal area to produce LPG. The produced LPG will be dispatched via tank trucks.

Study Approach by iFluids Engineering

A diagram outlining the study approach followed by iFluids Engineering. It starts with a title that reads Study Approach by iFluids Engineering, followed by four stacked boxes listing the key steps: Pipeline Modeling, Steady-State Analysis, Transient Analysis, and Recommendations. The layout presents a clear step-by-step methodology used in the project
Study Approach by iFluids Engineering

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

  1. Pipeline modelling: The pipeline system from jetty to terminal is modelled in fluid flow analysis software based on the provided layout and relevant drawing documents. Separate models for PHASE-I & PHASE-II are prepared.
  2. 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 models. The analysis results provide the initial conditions for the transient analysis.
  3. Transient state analysis: The Transient analysis for PHASE-I & PHASE-II is conducted using the steady-state 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.
  4. Recommendations: If surge mechanisms are required, they are recommended and verified in simulation.

The study’s outcome and recommendations were later implemented by IOCL on their cross-country Pipeline system.