Modeling, Simulation, And Optimization Of An Industrial Hydrocracking Unit

Duo to the increasing demand of low sulfur and high quality middle distillation oilproducts such as jet fuel and diesel and the easy availability of hydrogen from the catalyticreforming unit, the hydrocracking unit has become one of the most important secondarypetroleum refinery processes.Hydrocracking unit is a processing petroum refining process which converts heavy petro-leum feedstocks into desired lighter products. There are both hydrogenation and hydrocracki-ng reactions occurs stimultaneously, which is carried out in packed bed catalytic bed reactorsat high temperature, pressure and hydrogen-rich atmosphere.The main work of this paper is modeling and optimization of an industrial hydrocrackingreactor. In terms of theory, the kinetic model should ideally take into all reactions that thecomponents in the feedstock undergo. Hovever, in reality, it is difficult duo to the complexcomponents of the hydrocarbons in the feedstock and lack of detail kinetic data.In this paper, an improved discrete lunping model approach (based on Stangland,1974) isapplied to modeling an industrical hydrocracking reactor. The model is used to stimulation thereactor and to predict the products distribution. The kinetic paramers of the first principlereactor model were fine-tuned using60days stady-state industrial data by optimizationalgorithm (GA, genetic algorithm). The fine-tuned model was used to analyze the behavior ofof an industrial unit, after sensitivity analysis of the model; the reactor was optimized usingGA and GA+SQP. It was shown that the combined algorithm (GA+SQP) could integrate theadvantage of both GA and SQP, which could get better solution in hydrocracking optimizationapplication also. Apart from those contributions, other works in this paper are:1) Based onthe carbon balance principal of chemical reaction, a method of calculating the stoichiometriccoefficients of every reactant and resultant in each individual lump hydrocracking reactionhas been suggested;2) A kind of reactor pressure-change model has been proposed for the pr-ediction and optimization studies on the modeling of the hydrogenation reaction.