ASTM D6159 Hydrocarbon Impurities in Ethylene by Gas Chromatography

Scope: 

Using the ASTM D6159 test technique, methane, ethane, propane, acetylene, isobutane, propadiene, butane, trans-2-butene, butene-1, isobutene, cis-2-butene, methyl acetylene, and 1,3-butadiene are all determined in high-purity ethylene. Some manufacturing processes require high-purity ethylene, and the presence of trace amounts of certain hydrocarbon contaminants can have negative consequences. So, this test method can also be used to define requirements, as an internal quality control tool, or in development or research projects.

Test procedure:

According to ASTM D6159, a sample of gaseous ethylene is examined and in capillary gas chromatography, the gaseous sample is injected. A 6-port sampling valve and two wide-bore capillary columns connected in series are included with the gas chromatograph. A dimethyl silicone column and an Al₂O₃/KCl (porous layer open tubular {PLOT}) column are used.  Detection is accomplished using a flame ionization detector. The detector response is rectified in the integrated detector signal (peak regions). The total impurities are used to calculate the ethylene content, which is based on the hydrocarbon impurities. 

Video 01: Ethylene production

Specimen size:

In the ASTM D6159 test, a gaseous ethylene sample is collected in 1000 mL stainless steel cylinders equipped with a rupture for gas chromatography.

Data:

In ASTM D6159, the concentration of each impurity to the nearest ppmV is calculated as follows:

 Ci = (Cfi) (Ai) 

Ci = concentration of the impurity in the sample in ppmV 

Cfi = calibration factor 

Ai = integrated area of the impurity from the data acquisition system

Conclusion:

Using the ASTM D6159 test technique, methane, ethane, propane, acetylene, isobutane, propadiene, butane, trans-2-butene, butene-1, isobutene, cis-2-butene, methyl acetylene, and 1,3-butadiene are all determined in high-purity ethylene.