A suitable model for predicting the product quality of vacuum gas oil (VGO) catalytic hydrocracking is developed. Data were obtained using an experimental catalytic hydrocracking reactor loaded with the Ni-Mo/Al2O3-SiO2 catalyst. A set of experimental runs was conducted under various operating temperatures from 380 to 450 ℃. Three distribution models were used t...

A stable finite element scheme that avoids pressure oscillations for a three-field Biot’s model in poroelasticity is considered. The involved variables are the displacements, fluid flux (Darcy velocity), and the pore pressure, and they are discretized by using the lowest possible approximation order: Crouzeix-Raviart finite elements for the displacements, lowest order Raviart-Thomas-Nédélec ele...

Probabilistic model checking is a technique for the verification of probabilistic systems. The size of the state space is a limiting factor for model checking. We used bisimulation minimisation to combat this problem. Bisimulation minimisation is a technique where the model under consideration is first minimised prior to the actual model checking. We also considered a technique where the model ...

Abstract A finite element method with mass-lumping and flux upwinding is formulated for solving the immiscible two-phase flow problem in porous media. The approximates directly wetting phase pressure saturation, which are primary unknowns. discrete saturation satisfies a maximum principle. Stability of scheme existence solution established.

Building on the principles of structure-oriented lumping (SOL), chemistry-oriented lumping methods have been developed to describe the composition in tandem with the hydro-processing chemistry of heavy oils such as vacuum residue, de-asphalted oil, tar and bitumen. Recent advances in analytical chemistry have provided the necessary fundamental insights that are required to develop such models. ...

Hydrocracking is an important secondary process in the petroleum industry, generally used to process heavy oil cuts. The process is tailored to various needs of refineries in order to maximize middle distillates, gasoline, LPG and similar products. Therefore, kinetic modeling of hydrocracking reactors applied to upgrade vacuum heavy oil (Isomax) is important and needs to be investigated. In thi...

In this paper, we are interested in the modeling of wave propagation in viscoelastic media. We present a family of models which generalize the Zener’s model. We achieve its mathematical analysis: existence and uniqueness of solutions, energy decay and propagation with finite speed. For the numerical resolution, we extend a mixed finite element method proposed in [8]. This method combines mass l...

The finite element implement of the generalized Lorenz gauged A formulation has been proposed for low-frequency modeling. However, the inverse of mass matrix of intermediate scalar in the finite element implement leads to additional computation cost and dense coefficient matrix. In this paper we propose to adopt a diagonal lumping mass matrix in the finite element discretization of the generali...