Metal Fabrication: The Secret To A Great Roll Cage

4 Pipeline Metering Station Design Flaws That Increase Repair Costs

by Sally Burke

Pipeline metering stations are essential for tracking and managing the flow of natural gas over long distances, and the design of the station plays a big role in how well the equipment functions over long periods of time. A few simple mistakes can result in far more repair calls than usual as extra wear and tear causes the metering equipment to break down or even damages the pipeline itself. Design your metering stations right from the beginning by avoiding these four common mistakes to reduce what you spend on repair and maintenance over the lifetime of the each station.

Failure to Protect Against Sound Pressure

You can double-check every temperature and access control feature and still forget to compensate for the noise created by the metering equipment. Since loud noise causes physical vibrations in sensitive equipment, it's not uncommon for valves and regulators to end up damaged due to sheer volume. Metering stations can reach an excess of 110 decibels, especially with the echoing effects of metal or concrete walls. Padded baffles on the noise sources and muffling panels on the wall go a long way in reducing repair visits.

Mismanagement of Water in the Pipelines

Natural gas is dehydrated before being pressurized and sent through pipelines, but none of the current methods completely remove moisture from the mixture. There are tight tolerances for moisture in pipelines and metering equipment because excess moisture can corrode the equipment from the inside out. However, that moisture mixed into the gas can only cause this damage if it gathers on surfaces in the form of dew.

Maintaining the temperature in the metering station is the best way to combat dew, preventing corrosion in the pipeline and protecting the metering equipment from damage. Gas heaters are most commonly used but only to warm the pipes and valves that would be affected by dew so that none of the equipment in the rest of the station is in danger of overheating. In addition to preventing dew formation through heat control, consider extra safety features to fight corrosion like

  • Sensors to read the moisture and temperature levels of incoming gas and adjust the heating accordingly
  • Alarms to warn metering technicians if moisture accumulation is detected in the pipeline or valves
  • Extra regulators to prevent service interruptions when one is lost due to being clogged or corroded by water.

Issues with Maintaining the Hydrocarbon Dew Point

On top of preventing water from turning into dew, it's essential to keep hydrocarbons from solidifying as the gas travels through a metering station. Since metering usually involves decompressing the gas before it's diverted to lower pressure lines, this is a crucial point in which hydrocarbons are likely to form. These form solid masses, known as condensate, that clog up almost all the various valves, regulators, compressors used in the pipeline systems. Advanced sensors are the best way to calibrate temperature controls to keep the gas above the hydrocarbon dew point, which is best calculated regularly by a program instead of being managed manually, since hydrocarbon content can vary greatly in natural gas supplies.

Missing the Mark on Overpressure Protection

Finally, stay up to date on all regulated overpressure safety valves and other pressure relieving features in the metering station. Since clogs and other obstructions commonly form in these waystations, it's crucial that any sudden increase in pressure is relieved in the station rather than building up and damaging the rest of the pipeline. Keep your regulators well-maintained and regularly inspected by a repair technician. All devices should still release the minimum pressure of the pipeline when they fail, regardless of the maximum pressure they can handle when operating properly.

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