Multidimensional Chromatographic Applications in the Oil Industry

The analyses of gases in the oil industry comprises the determination of the inert gases (He, Hj, O2, Ar and N2), low-boiling compounds (CO, CO2, H2S, COS) and the lower hydrocarbons, saturated and unsaturated, up to hexane. Some special samples. Such as natural gas, have to be analysed for low concentrations of higher-boiling compounds (up to CiqS) since such compounds have an important influence on the calorific value and dew point. 

For measuring the inert species, some of which are present in the majority of gases, the thermal-conductivity detector (TCD) is often the detector of choice for gas analyses. Since the TCD is a concentration detector and its sensitivity is lower than that of mass-flow detectors such as the flame-ionization detector (FID), relatively high concentrations of compounds in the carrier gas are needed. This means that packed columns, with their high loadability, are still quite popular for such analyses. 

1 THE ANALYSIS OF TRACES OE SULFUR COMPOUNDS IN ETHENE AND PROPENE 

Ethene and propene are produced as bulk feedstocks for the chemical (polymer) industry and therefore their purities are important parameters. In particular, H2S and COS are compounds which may not only cause corrosion problems in processing equipment, but also may have detrimental effects on the catalysts in use. Eurthermore, air pollution regulations issued by, among others, the US Environmental Protection Agency (EPA) require that most of the sulfur gases should be removed in order to minimize Sulfur emissions into the atmosphere. Therefore, these compounds have to be determined to the ppb level. 

Refinery gas is the collective noun used for a range of off-gases originating from the various oil processes. A detailed knowledge of the composition of these gases is needed for three reasons, as follows  

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