Gas quality is a cornerstone of safe and efficient operations throughout the natural gas industry. Poor gas quality measurement poses significant risks for the public and infrastructure. The industry relies on compliance with quality standards to ensure the safety and efficiency of operations.
Factors Influencing Gas Quality
Specific requirements for gas quality are detailed in each pipeline’s tariffs. The standard composition of pipeline-quality gas consists mostly of methane. The actual specifications will differ between pipelines, but generally, gas should be free of any impurities that may interfere with the state of the commodity or damage equipment.
Unprocessed natural gas can contain many components other than methane, including butane, propane, water vapor, sulfur, and excess amounts of oxygen and nitrogen. This variability impacts equipment performance downstream, reduces efficiencies, and raises overall maintenance costs. Impurities in the gas can further degrade the quality, leading to serious risks, including hydrate formation and internal corrosion.
Hydrate Formation
The inadequate removal of water vapor leads to hydrate formation. Hydrates occur when the water molecules bond with other gases to form solid, crystalline compounds that cause blockages within the line. These blockages reduce flow efficiency and when they dislodge unexpectedly under pressure can pose a threat to the personnel and equipment.
Internal Corrosion
Contaminants inside the pipeline can lead to internal corrosion. In most cases, contaminants that are in the line, such as hydrogen sulfide (H2S), carbon dioxide (CO2), other chemicals, and water, can lead to corrosion. Corrosion affects the flow and health of the pipeline. Left untreated, corrosion leads to leaks and failures. Historically, 60% of all corrosion related pipeline incidents were caused by internal corrosion. This is why quality control of transported commodities is vital to removing or minimizing the contaminants in the line. Not only is gas quality monitoring a good practice to maximize the safety and efficiency of pipeline operations, it is now required by federal regulation. As recently as August of 2022, effective May of 2023, the Pipeline and Hazardous Materials Safety Administration (PHMSA) added requirements for natural gas pipeline operators to use gas quality monitoring methods at points where gas with potentially corrosive contaminants enters the pipeline to determine the gas stream constituents.
Evolution of Gas Measurement
Historically, gas measurement focused on ensuring that natural gas met the specific standards for combustion and transportation. However, with new energy sources being introduced, such as LNG (Liquified Natural Gas), hydrogen, and RNG (Renewable Natural Gas), there are additional complexities in ensuring the gas quality standards are still met. For example, for gas to be converted to LNG, it must undergo additional processing and has different specifications. Regardless of the energy source, operational efficiency and overall safety are still key.
The Role of Training
As the industry evolves with the introduction of new sources like LNG, hydrogen, and RNG, standards and regulations are changing. The knowledge needed as a measurement technician is vast; it’s essential that technicians stay informed and educated on gas quality measurement. The best way to prepare technicians is through a comprehensive training program to equip them with the necessary skills to monitor and maintain gas quality, understand the equipment, and troubleshoot. Recognizing this need, GTA has developed curriculum surrounding gas quality measurement, covering fundamentals and instrumentation.
Gas quality is not just about compliance; it’s about protecting the infrastructure and ensuring public safety while maintaining operational efficiencies. Through ongoing training and adherence to standards, the industry can continue to safely and efficiently transport commodities.
