How Do Debutanizer Columns Work?

July 14, 2017

Debutanizer columns (de-butaniser) are part of the fractional distillation family, but more on this family later. The target fraction, as the vessel descriptor implies, is butane. If you picture the natural gas stream entering the tall column, you can perhaps follow the fractionation process as it chemically separates the desired petroleum product. However, if process understanding should elude our non-engineering readers, we need to explain what's going on in this hydrocarbon soup, beginning with the input stream.

Humble Hydrocarbon Origins

As the natural gas flows into debutanizer columns, the NGL (Natural Gas Liquid) is boiled. High temperatures and pressure differentials process the evaporated organic compounds. This is a core part of the petroleum refinement process, with the various key organic compounds encountering similar fractionization configurations in their own monolithic separation columns. If our virtual camera were to pull back from the debutanizer column and pan, there's likely several other near identical structures installed in the same metal framework. This is the rest of the family, the ethane, propane, butane, and methane refinement vessels, and their job is to remove simple alkanes from the raw NGL stream.

A Debutanizer Primer

Push the focus forward again until the subject of our narrative is the only pressure vessel in our virtual frame. This is a fractionization tower that can reach as high as 60 metres tall, so it features as a dominant part of the refinery outline, as seen from great distances. The CH4 (Methane) component exists in the feedstock with the other alkane compounds, with the C4H10 (Butane) fraction only gaining its freedom when the vapourised gas condenses inside the array of valve trays that line the interior of the vessel. Obviously, then, this is no ordinary vessel, it's a sealed chamber that contains a wide assortment of precisely engineered valves and collectors. Based on thermal unit conversion technology, the boiling point of butane is used as a reference point here, an essential part of the distillation mechanism that will efficiently syphon butane from the raw NGL feed as long as the vessel's design maintains the process mandated temperatures and pressure.

Pure butane condenses in the debutanizer column when these variables are locked in by the architecture of the pressure vessel, so few impurities can form. Similarly, in the other alkane processing columns in this hydrocarbon refining frame, propane, ethane and methane are liberated and refined as valuable fuel sources. Again, though, the towering vessels must be built to an exacting standard if the thermal unit conversion system is to produce contaminant-free streams.

Contact Details

Fusion - Weld Engineering Pty Ltd
ABN 98 068 987619

1865 Frankston Flinders Road,
Hastings, VIC 3915

Ph: (03) 5909 8218

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