Erosion can be a major threat to liquid hydrocarbon transmission pipeline integrity if high liquid flow rates are combined with the presence of solid particles. Erosion may cause metal loss to the pipeline and in extreme cases lead to pipeline failure.
There is currently no industry-recognized guidance document or standard for determining erosional velocity limits for liquid hydrocarbon transmission pipelines. Many operators use the general form of the American Petroleum Institute RP 14E equation to determine erosional velocity, but it does not properly address the effect of the key parameters affecting erosion in liquid pipelines and could give erroneous results in some cases.
This paper presents a guideline to determine erosional velocity limits for liquid hydrocarbon transmission pipelines, developed based on a multi-analytical probabilistic approach that integrated results from two industry-recognized erosion prediction models.
The guidance developed allows pipeline operators to reduce capital costs when designing new pipelines or can provide engineering justification for increasing the throughput of existing facilities while maintaining pipeline integrity relative to the threat of erosion.
Erosion is a major threat to liquid hydrocarbon transmission pipeline integrity when high liquid flow rates are combined with the presence of solid particles. However, there is currently no generally accepted guidance document or standard by which liquid petroleum pipeline operators can define maximum allowable velocities to manage the threat of erosion in their pipelines.
In liquid piping systems where solids might be present, a maximum velocity of 5 m/s (∼17 ft/s) is often used by industry as a limit to minimize erosion.1 The International Organization for Standardization (ISO)(1) 13703 also recommends a maximum velocity of 5 m/s (∼17 ft/s) for lines transporting liquids in a single phase by pressure differential, to minimize flashing ahead of the control valve.2 For calculating erosional velocity in pipelines with two-phase flow, this ISO standard refers to the equation in the American Petroleum Institute (API)(2) Recommended Practice 14E, henceforth referred as the API RP 14E equation.3 However, ISO 13703 standard includes a note indicating that computer-based models that consider the effect of geometry, material type, solids properties, and fluid velocities and properties, can be used as an alternative to the API RP 14E approach, which can be overly conservative for many conditions.2
