Rig site chromatographic column reconditioning

A gas chromatography (GC) apparatus comprising:

• a housing;
• a column assembly including a main column and a trapping column in fluid communication with a multiport valve, the main column configured to separate at least methane, ethane, propane, butane, and pentane compounds in a gas stream, the trapping column configured to remove interfering alkene or alcohol compounds from the gas stream, the column assembly further including a heating element configured to heat the trapping column;
• a flow manifold in fluid communication with the column assembly, a carrier gas injection port, a reverse flow injection port, and a sample injection port;
• a GC detector in fluid communication with the flow manifold and the main column;
• and
• an electronic controller configured to cause the GC apparatus to make a plurality of GC measurements on the rig site by flowing a gas stream in a forward direction through the trapping column and the main column to the detector, flow a reconditioning gas in a reverse direction through the trapping column after completing the plurality of GC measurements, and heat the trapping column to a temperature above 120 degrees C. while flowing the reconditioning gas in the reverse direction to recondition the trapping column.

A method for reconditioning a gas chromatography apparatus at a rig site, the method comprising:

• providing a gas chromatography (GC) apparatus including a trapping column, a precut column, a main column, a detector, and a multiport valve in fluid communication with the trapping column, the precut column, and the main column, the main column configured to separate at least methane, ethane, propane, butane, and pentane compounds in a gas stream, the precut column configured to remove hydrocarbon compound having a number of carbon atoms above a threshold from the gas stream, and the trapping column configured to remove interfering alkene or alcohol compounds from the gas stream;
• using the GC apparatus to make a plurality of GC measurements on the rig site by flowing the gas stream in a forward direction through the trapping column and the main column to the detector;
• setting the multiport valve to a first position after completing the plurality of GC measurements, the first position providing fluid communication between a reverse flow injection port and the trapping column and the precut column;
• opening the reverse flow injection port to cause a reconditioning gas to flow in a reverse direction through the precut column and the trapping column;
• and
• heating the column assembly to a temperature above 120 degrees C. while the reconditioning gas flows in the reverse direction to recondition the trapping column.