ONLINE PYROLYSIS OF ASPHALTENES AND KEROGEN STUDIED BY DIFFUSE REFLECTANCE FOURIER-TRANSFORM INFRARED-SPECTROSCOPY

Use of diffuse reflectance infrared spectroscopy for on-line monitoring of pyrolysis of geochemical samples is reported for the first time. The technique acquires a full reflectance spectrum at selected and increasing temperatures for a single sample. Two asphaltene samples and the parent kerogen sample were analysed and their on-line spectra are presented and their behaviour during pyrolysis discussed. It is shown that asphaltene decomposes at lower temperatures than kerogen. Depletion of carbonyl groups from the asphaltene matrix goes to completion before the complete elimination of aliphatic chains.