Global demand for natural gas is forecast to increase by an average 1.6% each year in the next five years. New pipelines are being constructed to move the additional supply of dry natural gas to meet demands across the globe, but natural gas must first be processed effectively for transportation – a complex process.
A pipeline process
Before natural gas can be commercialised, it needs to be gathered, compressed, dehydrated, treated, conditioned, processed and marketed.
Natural gas is first collected using gathering lines, made of up of steel pipes buried underground that carry un-odourised raw gas at a pressure of 715 pound-force per square inch (PSI) and 49.2975 BAR. The system works on the principle of gas moving from high pressures to lower pressures. Similar to how tree branches inter-connect, gathering lines collect gas from smaller lines and feed them into the main pipeline for transport or move them to a central collection point for processing.
At gas processing facilities, raw natural gas undergoes a complex industrial process to remove impurities and various non-methane hydrocarbons and fluids. The plants purify raw natural gas by removing common contaminants such as water, carbon dioxide (CO2) and hydrogen sulphide (H2S). Once gathering and processing is complete, the plant can deliver pipeline-quality dry natural gas, ready for transportation to residential, commercial and industrial customers.
Natural gas processing removes impurities and separates natural gas liquids (NGLs) from dry gas. Processing is valuable for operators because natural gas liquids can have their own applications as separate components and are worth more when extracted from the raw gas stream. NGLs include ethane, propane, normal butane, isobutane and natural gasoline. Ethane, for example, is useful in the production of ethylene – a hydrocarbon widely used in the chemicals industry.
However, long-haul natural gas pipelines have strict regulations for pipeline-quality dry natural gas. There can only be certain levels of NGLs in the gas, and the impurities in raw natural gas – such as water and CO2 – can damage pipelines.
The heat is on
Natural gas gathering and processing can lead to flaring. Facility start-ups and shutdowns may use flaring as part of normal safe operation, and flares are also on standby to ensure plant safety in the event of unplanned issues such as equipment breakdown.
In the oil and gas industry flaring is now more tightly regulated and operators must measure and report flaring levels. While regulators typically require 5% accuracy, only ultrasonic technology has the potential to keep up with stricter requirements and changing environments. Using the latest ultrasonic sensing technology, Fluenta’s FGM 160 Flare Gas Meter is used in processing plants across the globe to accurately measure and monitor flare gas.
For more information on Fluenta’s FGM 160 Flare Gas Meter, click here.