Feasibility of FCC processability of VGO from Argentinian shale oil and a DCC approximation

DIETTA, LEANDRO EMANUEL; GARCÍA, JUAN RAFAEL; FALCO, MARISA; SEDRAN, ULISES

Buenos Aires

Congreso; 11th World Congress of Chemical Engineering; 2023

AAIQ

The current need for scientific and technical knowledge about the properties and processability of crude oils of nonconventional extraction source is driven by the growing demand of light olefins and middle distillates [1], as well as the sustained growth in the exploitation of non-conventional oil fields itself. Given the reasons stated above, this paper compares the fluidized bed catalytic cracking (FCC) processing of two vacuum gas oils (VGO) from conventional (VGOESC) and non-conventional (VGOSOIL) extraction crudes at two temperatures, 550 (typical of FCC) and 600 ºC (an approximation to the deep catalytic cracking (DCC) technological option). The experiments were performed in a laboratory batch fluidized bed reactor with internal recirculation, the CREC Riser Simulator [2]. An equilibrium catalyst of the gasoline maximization type, was used for the experiments. The feedstocks were obtained by the atmospheric and subsequent vacuum distillation in the laboratory of the respective crude oils to obtain the corresponding VGOs. The reaction products were analyzed by on-line gas chromatography (HP-1 column and FID detector). The coke on the catalyst was quantified by temperature-programmed oxidation and subsequent methanation of carbon oxides. The conversion was defined as the sum of the mass yields of dry gas (DG, C1-C2), liquefied petroleum gas (LPG, C3-C4), gasoline (C5-216°C), light cycle oil (LCO, 216°C-340°C) and coke. Both feedstocks showed similar conversions, except at low reaction times. At 550°C the conversions reached values of approximately 70% while at 600°C the conversions were almost 20% higher. The comparison between feedstocks shows that the largest differences in the product yields were seen at 600°C. VGOSOIL showed higher yields of gas products while higher yields of LCO were obtained with VGOESC. Regardless the feedstock, the gasoline yields were essentially the same. As both feedstocks have similar simulated distillation curves, the yield differences can be attributed to their different compositions. Coke yields were essentially the same with both feedstocks. For each feedstock, at similar conversions, DG yields at 600°C doubled those at 550°C. LPG yields showed a small decrease with the temperature, but the olefinicity of the cut increased. Gasoline yield decreased with the temperature at similar conversions while LCO keep their values. In conclusion, FCC processability of non-conventional VGO is possible under typical FCC conditions, with larger gases yields and the conservation of gasoline yields. More severe conditions, typical for DCC, induced good performances, with larger conversions, towards the production of higher amounts of light olefins, conserving gasoline yields and decreasing the yields of less valuable products, such as LCO.