To get natural gas to a clean-burning fossil fuel which safely keeps our stoves lit and houses warm, the gas (methane) is subjected to multiple filtration processes during every phase of production.

When processed natural gas is consumed, it burns extremely clean and has significantly lower levels of harmful emissions, as compared to other fossil fuels (oil and coal). It is for this reason natural gas is being touted as the fuel to bridge us to a sustainable energy future.

Raw natural gas however, as it comes from the drilling process is far from clean. In fact, raw natural gas after extraction can contain impurities such as: ethane, propane, butane, pentanes, water vapor, hydrogen sulfide (H₂S), carbon dioxide (CO₂), helium (He), nitrogen (N), and other compounds. To get methane safely from the earth to our homes, natural gas goes through four phases of production and all of them require filtration:

Natural Gas Production

After a well has been drilled the natural gas is extracted from the earth with its own pressure allowing it to naturally rise to the surface. The gas coming from the earth is full of contaminants and is filtered using coalescing filters to remove solids, like sand and dust and water, which could damage compressors. After the natural gas has been compressed it goes through another filtration to remove compressor lube oil and is sent to treatment facilities.

Treatment of Natural Gas

At treatment facilities natural gas is filtered through multiple filtration processes to remove hydrocarbons, water vapor, contaminants and acid gas. The methane needs to be filtered and treated prior to transportation, and among the treatment processes are:

Amine Sweetening: the removal of acid gases like hydrogen sulfide (H₂S) and carbon dioxide (CO₂) by subjecting the natural gas to amines and subsequently removing other trace hydrocarbons before the gas is sent to the stripper.

Desiccant Dehydration: a process where coalescing filters are used to remove unwanted contaminants and the gas is dried using desiccants like molecular sieve or silica gel.

Glycol Dehydration: a process where coalescing filters are used to remove liquids and particles and glycol is used to remove water vapor.

Natural Gas Transmission (Pipeline)

Natural gas is transported through a network of pipelines and at times is even stored. The natural gas is sent through a two-stage filtration, then through a compressor station, heated, and filtered again. Some of contaminants within pipelines can be CO₂, which is created by corrosion damage of the pipeline.

[Below, the Shawndra R100 Coalescing Pipeline Filter Multiple Stage. These coalescing filter-separators use dry type replaceable coalescer elements and removes both solid particles and liquids]

Distribution

Natural gas makes its way to consumers through distributors. Methane has a tendency to lose pressure from friction as it flows through pipelines, so compressor stations are required to maintain high enough pressure to flow. Pigging the lines, a common cleaning practice can displace solid and liquid contaminants so the pipeline needs to be filtered both before and after compressor stations for both particulates and liquids.

[To the right, a Shawndra Pressure Filter Vessel used to remove particulates from natural gas pipelines.]
 

Like most natural ingredients, natural gas requires a bit of engineering and tweaking to deliver it to market safely. At every phase of production, methane is filtered multiple times to help assure safety and prevent damage to our pipelines. Without the filtration process, natural gas would never be recognized as the “clean fossil fuel” and the best nonrenewable energy to bridge us to a sustainable energy future.