PCA Reduction in naphtenic base oils by hydrotreatment

PETR 75

Elizabeth Gómez U, mariael.gomez@ecopetrol.com.co1, Liliana Santos, mariel.gomez@ecopetrol.com.co2, and Omar David Ordoñez, mariael.gomez@ecopetrol.com.co2. (1) CATALYST RESEARCH GROUP, ECOPETROL - ICP-, AUTOPISTA BUCARAMANGA-PIEDECUESTA KM 11, Bucaramanga (Santander), Colombia, (2) HYDROTREATMENT GROUP, ECOPÉTROL REFINERY, REFINERIA DE BARRANCABERMEJA, Barrancabermeja (Santander), Colombia
Mutagenicity has been related to polynuclear aromatics (PCA). Results from long term mouse skin painting carried out by Shell for base oils demonstrated a correlation between tumor incidence and weight percentage of DMSO (dimethyl sulfoxide) extract. Results showed that base oils containing more than 3% by weight of PCA should be regarded as carcinogens.

Two fractions taken from an industrial plant were hydrotreated in a Pilot Plant. This paper shows the effect of the temperature in catalytic activity of PCA removal. Five temperatures were tested. Results of mass spectrometry, associated with PCA determination show that PCA are reduced as the temperature increase. However there is a critical temperature above it the recombination of aromatics takes place increasing the PCA. Determination of this point is important to guarantee PCA below 3%. Based on this, an Hydrogen quench between the two industrial reactors was installed to keep temperatures below the critical one.