Dynamic Simulation of Industrial Reformer Reactors

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Author(s) Wordu, Animia Ajor
Pages 1301-1317
Volume 2
Issue 7
Date July, 2012
Keywords Dynamic Simulation, Continuous-Catalyst-Stacked-Reactor, Constrain optimization, Four-Lump Kinetics.

Abstract

This research focused on mechanistic kinetic model for the upgrading of the low component fractions petroleum naphtha (generic) of Nigerian reformer reactors. Four main constituent lumps were considered in the synthesis of the rate equations that describe the mass action velocity for the depletion processes of the feed in the reactors. The reactors under study is a continuous catalyst reforming stacked reactors, one reactor on top of the other with gravity mobile flow of catalyst from reactor 1, 2 and 3. The plant design brings to the barest minimum the deactivation of catalyst by the precursors of the reactions. Energy and component mass balance approach were adopted to develop the dynamic model for the research. The models were parameterized by benchmarking against industrial reformer plant data. The equations are non-linear intractable partial differential equations describing the dynamics of the reactors are very stiff to solve. The resolution of the model equations depends on the obtaining the values of the activation energies for the four lumps chemical species reactions. A constrained optimization which considers the minimization of the sum of the squares of difference of the objective function was carried out by integrating the differential equations numerically. The dynamic equations were converted into a set of ordinary differential equations by applying numerical method of lines (MOL) of finite difference approximation of the spatial derivatives, and the equations integrated with respect to time. The dynamic equations were resolved using the mat-lab ode solver-23. The comparison of deviations of dynamic model with the steady state model results showed naphthene 2.2 percent, paraffin 0 percent, aromatic -1.6 percent and temperature 0.13 percent, which are consistent with the steady state values of naphthene 3.7 percent, paraffin 0.6 percent, aromatics 1.2 percent and temperature 1.03 percent. A sensitivity analysis carried out on the open loop of the reactor system showed that the reactor temperature, pressure and activity of the catalyst are the major variables for striking a balance economically.

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