Petroleum Refining

Kinetic Modeling Approaches Part 2 (Petroleum Refining)

Stangeland (1974) developed a kinetic model for predicting hydrocracker yields using correlations based on the boiling point of each of the pseudocom-ponents that characterize the cut. The model includes four parameters: k0 and A quantify each pseudocomponent ‘s reaction rate, C gives the butane yield magnitude, and B varies with both the type of feed […]

Reactor Modeling Part 1 (Petroleum Refining)

Classification and Selection of Reactor Models For decades, different models have been developed to understand, design, simulate, or optimize the performance of the reactors used in the petroleum refining industry. This development has been parallel to the need for more detailed prediction capability, motivated by continuous changes in process conditions (i.e., nature of feedstocks, new […]

Reactor Modeling Part 2 (Petroleum Refining)

Continuous Pseudohomogeneous Models Steady-State Continuous Pseudohomogeneous Models Among different approaches, steady-state continuous pseudohomogeneous models have been widely reported in the literature. This is due to their reliability and simplicity. A pseudohomogeneous model generally assumes a power–aw kinetic type, although sometimes Langmuir-Hinshelwood expression has been employed. Use of the power law for kinetics has been questioned […]

Reactor Modeling Part 3 (Petroleum Refining)

Pseudohomogeneous models Based on kinetics Advantages • Currently used for testing and evaluating a catalyst in bench-scale reactors. • When the reaction being studied is first – order or pseudo – first – order, a residence-time distribution curve can be used to calculate the intrinsic reaction rate constants, which allows determining contacting efficiency. • Easy […]

Reactor Modeling Part 4 (Petroleum Refining)

When a high-purity hydrogen stream without gas recycle is used, such as in the case of some laboratory and bench-scale HDT reactors, or when the gas recycle has been subject to the purification process in commercial units, values of partial pressure (pG) and liquid molar concentrations (CL) of H-S, NH3, and LHC at the entrance […]

NOMENCLATURE Part 1 (Reactor Modeling in The Petroleum Refining Industry)

Glaso’s coefficient for viscosity correlation; energy parameter in equation of state Power terms for temperature, hydrogen partial pressure, and LHSV, respectively Parameters Model parameters Gas-liquid interfacial area per unit reactor volume, cm2/cm3 Liquid (or gas)-solid interfacial area per unit reactor volume, cmS/cm3 Effectively wetted area Reduced parameter of energy parameter a, preexponential factor Bed-wall reactor […]

NOMENCLATURE Part 2 (Reactor Modeling in The Petroleum Refining Industry)

Yield of gasoline, wt%, conversion Mole fraction of the component i in the liquid phase, Mole fraction of the component i in the gas phase, Constant Axial reactor coordinate, cmr; diesel yield, wt% Compressibility factor, dimensionless Constant employed in Bosanquet’s formula, dimensionless Empirical exponent; rate constant, h-1; model parameter Generalized temperature function of component i […]

The Hydrotreating Process Part 1

Catalytic hydrotreating (HDT) is applied extensively in the petroleum refining industry to remove impurities, such as heteroatoms (sulfur, nitrogen, oxygen), PNAs (polynuclear aromatics), and metal-containing compounds (primarily V and Ni). The concentration of these impurities increases as the boiling point of the petroleum fraction increases. S-, N-, O-, and PNA-containing compounds are found in low-molecular-weight […]

The Hydrotreating Process Part 2

Process Variables During hydrotreating operation at different scales (laboratory, microreactor, bench scale, pilot scale, and commercially), there are four main process variables that have a great impact on reaction conversion and selectivity as well as on the activity and stability of the catalyst: (1) total pressure and hydrogen partial pressure, (2) reaction temperature, (3) H2/oil […]

The Hydrotreating Process Part 3

Other Process Aspects The operation of hydrotreating reactors is considered to be very close to adia-batic because the heat losses from the reactor are usually negligible compared with the heat generated by the reactions. The exothermality of hydrotreating reactions, predominantly HDS and the hydrogenation of aromatics, can cause (LHSV: liquid hourly space velocity) or a […]