PURPOSE: To obtain a thermal cracked oil in high yield, by thermally cracking a heavy oil at a high temperature in the first stage, taking out the resultant thermal cracked oil and decomposition residue, thermally cracking the thermal cracking residue at a high temperature in the second stage, mixing the thermal cracking product with the thermal cracking oil, distilling the resultant mixture, and circulating the resultant residue through the thermal cracking step.
CONSTITUTION: A heavy oil is introduced through a line 1 into the first thermal cracking reactor 15 and thermally cracked at 400W500°C. The resultant thermal cracked oil is then taken out of a line 3, sent to a distillation column 17, and the thermal cracking residue is taken out of a line 9 and introduced into the second thermal cracking reactor 16 and thermally cracked at 510W650°C. The resultant thermal cracked oil obtained in the second thermal cracking step is taken out of a line 7 and sent to the distillation column 17. The thermal cracked oil in the first step and the above-mentioned thermal cracked oil are distilled to give the aimed purified thermal cracked oil. The resultant residue after the distillation is then circulated through the first thermal cracking reactor 15 by a line 11 and further thermally cracked.
MORIMOTO YASUYUKI
AIKAWA SHINICHI
KUDOU HIDEHIKO
