Abstract:

The separation and qualitative analysis of 54 common C₅-C₇ hydrocarbon components on three Al₂O₃ capillary columns, including S type, KCl type and M type, were investigated in detail. The results showed that the separation of the 54 C₅-C₇ hydrocarbon components were partly different on these three Al₂O₃ capillary columns, and the most of C₅-C₇ hydrocarbon components could be well separated, except that some of them couldn't achieve a baseline separation or co-eluted. Linear temperature programmed retention indices of the 54 C₅-C₇ hydrocarbon components, including 15 C₅ hydrocarbons, 25 C₆ hydrocarbons and 14 C₇ hydrocarbons, were determined on these three Al₂O₃ capillary columns. The determination of linear temperature programmed retention indices for these C₅-C₇ hydrocarbon components on Al₂O₃ capillary columns provided a basis for the qualitative analysis of them. At the same time, a real pyrolysis gas sample from one of the petrochemical plants was qualitatively analyzed according to the linear temperature programmed retention indices, and the contents of C₅-C₇ hydrocarbon components were determined. The application field of Al₂O₃ capillary column was expanded and it is helpful for the analysis of light hydrocarbons in petrochemical enterprises.

Key words: Al₂O₃ capillary chromatographic column, C₅-C₇ hydrocarbon components, gas chromatography (GC), pyrolysis gas