Effect of addition of organic sulfur compound and metal salts on pyrolysisof atmospheric residue

The thermal decomposition of atmospheric residue was carried out in a tubul ar type reactor at 480 degrees C to elucidate the effects of addition of 3- pentaerothritol tetrakis-3-mecaptopropionate (PTMP) and/or metal naphthates on the conversion of the residue to light oil and on the coke formation at the reactor wall. When PTMP (1000 ppm) was added in the residue, a slight amount thermal cracking was observed, but no deposition of coke on the reac tor wall was observed. On the other hand, the addition of ferric naphthate (100 ppm) significantly increased the amount of decomposition of the residu e. However, a large amount of coke was deposited on the reactor wall. When PTMP and ferric naphthate were added simultaneously to the residue, the dec omposed oil included a substantial amount of light oil fraction; however, t he coke deposited on the reactor wall was less than when ferric naphthate w as added alone. These results indicate that PTMP plays an important role to terminating the recombination of hydrocarbon radicals, produced by thermal decomposition of the residue accelerated by addition of ferric naphthate. Thus, the simultaneous addition of PTMP and ferric naphthate will make it p ossible for the petroleum industry to convert atmospheric residue to light oil without additional investment for facilities and without additional cos t for operations.