New Developments in Deep Hydroconversion of Heavy Oil Residues with Dispersed Catalysts. 2. Kinetics Aspects of Reaction

This paper discusses the results of hydrocracking experiments performed on a vacuum residue of Belaym crude in the presence of molybdenum naphthenate (MoN) as hydrogenation catalyst precursor and conducted in batch mode within a wide range of operating conditions and catalyst loading. The influence of severity on product distribution and quality is described as well as a kinetic analysis of the data. Results of this work demonstrate that the in-situ decomposition of MoN generates micrometer-sized particles of very active hydrogenation catalysts molybdenum disulfide utilizing the sulfur present in the feedstock. The catalyst provides hydrogen in an active form for stabilization of the free radicals produced by the thermal cracking of the petroleum residue so that high conversion to distillate product (500°C-) can be obtained with minimum coke production. The kinetic analysis of the data shows that the step of MoN sulfidation to generate MoS2 is very fast compared to feedstock conversion and does not influence the kinetics of distillate production that is thermally controlled (activation energy of 56.7 kcal/mol) and whose apparent over all order of reaction is close to 2.