Establishing the Maximum Carbon Number for Reliable Quantitative Gas Chromatographic Analysis of Heavy Ends Hydrocarbons. Part 2. Migration and Separation Gas Chromatography Modeling

Abstract

International audienc

Reactive Transport and Its Implications on Heavy Oil HTGC Analysis – A Coupled Thermo-Hydro-Chemical (THC) Multiphysics Modelling Approach

“…This approach, has been programmed in MATLAB, and has been compared in [7] with the solution yielded by the COMSOL-MATLAB model developed in [19], which solves the diffusive-convective equation by finite elements.…”

“…The fluid flow and transport of chemical species considers only the convection process of the carrier gas transporting each of the species at its own speed from the GC inlet to the GC outlet. The diffusion of the chemical species in the gas phase has been concluded to be negligible based on a previous investigation [19] which compares the advection process (convection plus diffusion) and the convection process only, demonstrating no difference between the chromatogram peaks results using both approaches.…”

“…Discretized into finite time-steps of Eq. (2) allows tracking of the position of the analyte at every x position through the GC column at every time step until the peak reaches the column outlet [18,19] at the final time step which cumulated represents the retention time for that analyte as explained in [4]. And lastly, K and β are the distribution factor and phase ratio of the column described in Eq.…”

“…(3), η(T(t)) corresponds to the viscosity of the carrier gas [21,22]. (See summarised details in [19]), P in and P out are the inlet and outlet pressures of the GC column. r o is the inner radius of the column and P(x) is the pressure at position x described with Eq.…”

Fast and accurate numerical method for predicting gas chromatography retention time

“…If hold-up time can be described as a function only of time (but not of the position in the column), it is possible to apply separation of variables in the differential equation [3,24,25], describing the motion of an analyte, resulting in the well-known equation GC (Eq . 6),…”