Pigging speed is crucial to a safe and effective natural gas pipeline cleaning pigging program. A cleaning pig must obtain a seal within the line for the separation of dissimilar fluids in products pipelines, for condensate removal in gas pipelines, for commissioning and for providing secondary barriers for pipeline isolation. Pigs are designed for optimal cleaning at around 8 m/s. Slower speeds could result in a pig being held up at a weld, potentially resulting in a dangerous situation when the pressure builds behind the pig, and abruptly dislodges the pig, thrusting it away at speeds over 60 mph. Higher speeds will result in the pig bypassing debris and liquids, proving ineffective.
Product Flow Reduction Concerns
In large natural gas pipelines with ultra high velocities, operators are reluctant to reduce flows down for pigging, as this results in a reduction of revenue generating delivery. This poses a unique challenge in terms of effective cleaning for corrosion mitigation purposes or pre ILI runs.
Active Speed Control Pigging is Now Possible
To meet this challenge, Inline Services has designed a new series of Speed Control Pigs, specifically for these circumstances, which can maintain optimal cleaning speeds of 6 to 10 mph within a gas flow velocity of up to 33 mph. The Speed Control Pigs’ IMU constantly monitors and records its surrounding environment, which can be exported and analysed onsite. At predetermined speeds increased bypass is allowed through the pig to slow its progress and bypass is reduced to increase speed. The extra bypass through can be useful for moving loose deposits ahead of the pig. In addition, Inline’s Speed Control Cleaning tool can aid in the use of chemical inhibitors, determining quantities dispersed, recovery and liquids balance within the line.
How Does The Speed Control Pig Work?
The below animation shows how the Speed Control Pig uses bypass controls to maintain optimal cleaning speeds while traversing high velocity gas transmission pipelines.
We Can Help Improve Your Natural Gas Pipeline Integrity Program
For more information about a recent project utilizing our Speed Control Pig or to discuss how Inline Services can improve your Natural Gas Pipeline Integrity Program contact us at 281.401.8142 or toll free at 888.973.0079.