PYROLYSIS OF HIGH-BOILING PRODUCT FRACTIONS FROM PETROLEUM VACUUM DISTILLATE HYDROCRACKING

A high-boiling product from petroleum vacuum distillate hydrocracking was used as a feedstock for pyrolysis to light alkenes. The high boili ng product was distilled to yield five fractions. Pyrolysis of these f ractions was performed in a laboratory pyrolysis apparatus. The fracti ons pyrolysed were analyzed by a procedure consisting of their separat ion by liquid adsorption chromatography and subsequent characterizatio n of the chromatographic fractions obtained by elemental analysis, vap our pressure osmometry, H-1 and C-13 NMR spectrometry and mass spectro metry. In this way the relation between the chemical structure and com position of the pyrolysed fractions and the yield of light alkenes was obtained. It was found that the fraction of the high-boiling product boiling above 486 degrees C was not a suitable pyrolysis feedstock eve n if its BMC index was good; this fraction had a low alkane content.