r+k Consulting Engineers

Optimalisation of a pipeline design

An existing pipeline installation will be upgraded and several pipelines will be replaced with new ones. In one of the sections, a pipeline connecting different parts of the installation is redesigned and the new design has to be checked to see if it is in accordance with the ASME B31.3. The pipeline is mostly underground and placed on supports, while the soil will settle around 10 mm every year.

Key features of this project are:

  • Pipe dimensions (D x t): 762 mm x 22 mm, 609.6 mm x 24.6 mm and 508 mm x 20.6 mm.
  • Pipe material: A671CC70 steel and A333Gr.6 steel.
  • Important loads: internal pressure: 80 barg, temperature range: from -46°C up to 50°C, soil settlement: 300 mm.

After modelling and calculating, the original (re)design (as shown on the left below) was proven to be an acceptable solution.

Pipeline optimalisation

Pipeline optimalisation: Original (re)design on the left, optimised alternative layout on the right

The second part of this assignment was to make an alternative design, in which less material was used, while still being in accordance with ASME B31.3. The result can be seen in the picture on the right. Differences between redesign and alternative design: 11% reduction in pipeline length, less bends (from 24 down to 21) and smaller bend angles (45° instead of 90°) and less supports (from 31 down to 26). The alternative design reduces costs significantly.

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