Separation of C-5 - C-7 hydrocarbon components on Al2O3 capillary column and its application

The separation and qualitative analysis of 54 common C-5-C-7 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 C-5-C-7 hydrocarbon components were partly different on these three Al2O3 capillary columns, and the most of C-5-C-7 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 C-5-C-7 hydrocarbon components, including 15 C-5 hydrocarbons, 25 C-6 hydrocarbons and 14 C-7 hydrocarbons, were determined on these three Al2O3 capillary columns. The determination of linear temperature programmed retention indices for these C-5-C-7 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 C-5-C-7 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.