Richard J. Quann

Building useful models of complex reaction systems in petroleum refining

The identity and composition of petroleums countless molecular components is beyond the resolution of analytical techniques. Nonetheless, models of petroleum refining processes must have a molecular basis to be useful in predicting the molecular composition of products and their physical and quality properties required by industry specifications. Strategies for solving this seemingly intractable problem are presented.

Catalytic hydrodemetallation of petroleum

Publisher Summary This chapter discusses the elements of physical chemistry, heterogeneous catalysis, and reaction engineering that are necessary for a basic understanding of catalytic hydrodemetallation. It focuses on vanadium and nickel removal because these are the most abundant metals in petroleum. Following this, it discusses the nature of the metal compounds in petroleum oils and the targeted reactants. The chemical composition of the host petroleum and residuum is described, including a discussion of the two classes of metal compounds: (1) metalloporphyrins and (2) nonporphyrin metals. A comparison between the characteristics of vanadium and nickel complexes and their distribution in residua is also presented. Commercial residuum hydroprocessing technology is then discussed to establish the role and requirements of hydroprocessing in the overall refinery residuum conversion scheme. Finally, the kinetics and mechanisms of catalytic HDM reactions are presented and future perspectives for the study of residuum hydroprocessing and the rational design of hydrodemetallation catalysts and processes are highlighted.

Hydrogenation of polynuclear aromatic hydrocarbons. 2. quantitative structure/reactivity correlations

Abstract A consistent data base of reaction pathways, kinetics, and mechanisms for catalytic hydrogenation of one-, two-, three-, and four-fused aromatic ring compounds allowed for correlation of their Langmuir-Hinshelwood-Hougen-Watson (LHHW) rate law parameters with molecular structure. A total of 68 hydrogenation and dehydrogenation rate law parameters for 28 aromatic and hydroaromatic compounds were summarized into 7 parameters for quantitative structure/reactivity correlations (QS/RC) that characterized the associated set of series of homologous reactions, i.e. reaction families. Evaluation of the 28 LHHW adsorption constants was accomplished by imposing a correlation betwen the adsorption constant and the number of aromatic rings and the number of saturated carbons. Surface reaction rate constants correlated with the enthalpy of hydrogenation and the highest bond order in the aromatic ring being saturated. Semiempirical molecular orbital calculations provided acceptable estimates of the enthalpy of reaction, which, via compensation, provided estimates of the entropy of reaction, and thus equilibrium constants. The overall parity between measured parameters and those predicted by the 10 QS/RC parameters was very good, and allowed for 88% reduction in the number of parameters needed to model the saturation kinetics of polynuclear aromatic hydrocarbons.