Molecule Simulation for the Secondary Reactions of Fluid Catalytic Cracking Gasoline by the Method of Structure Oriented Lumping Combined with Monte Carlo

Abstract

To overcome the drawback of the traditional lumping method, a new method constructed from structure oriented lumping (SOL) combined with Monte Carlo (MC) to simulate the secondary reactions process of fluid catalytic cracking (FCC) gasoline was developed. The SOL method was applied to represent the feedstocks and products configuration framework; then, more than 60 item reaction rules were established to produce all the reaction networks for the secondary reactions of FCC gasoline. By integral calculating each molecule reaction probability using the MC method, the product distribution thus can be obtained. Three samples of catalytic cracking gasoline, taken from the industrial FCC units of China have been used as feedstock of the simulation to check the validity of the proposed method. Some integral properties, such as average molecular weight, element compositions, and hydrocarbon compositions were predicted. The yield of upgraded gasoline, dry gas, liquefied petroleum gas (LPG), light cycle oil (LCO), heavy oil, coke, and olefin changes with extent of reaction were also simulated with this method and the predicted results agreed well with the experimental data.

Feedstock molecular reconstruction for secondary reactions of fluid catalytic cracking gasoline by maximum information entropy method

“…4 and 5 show the results of the same calculation task executed by the traditional MC method developed in our previous work [10]. As shown in Fig.…”

“…To create each molecule vector, the random sampling of Monte Carlo (MC) method will be used, which provides a large ensemble of calculated molecules whose properties will be compared with the experimentally measured values. The construction of a set of representation molecules is accomplished by rigorous assembly of different structural features or increments [10]. In the third step, the mole fractions of the structural increments contained in the molecular library are adjusted by the maximum information entropy method (MIEM) to achieve a better matching with the desired characteristics, e.g., the average molecular weight.…”

“…However, it cannot give a proper representation for each molecule like the molecule simulation methods do. Considering the characteristics of molecule methods and MC method, a method of SOL combined with MC method was employed to simulate the system of secondary reactions of FCC gasoline from molecular scale in our previous work [10]. However, numerous sampling and a very long simulation time are needed by using this combined MC method to obtain a satisfactory result because of the uncertainties of the stochastic sampling involved.…”

Progress in kinetic predictions for complex reaction of hydrocarbons: from mechanism studies to industrial applications

“…For example, a simulated annealing algorithm was adopted to study a SOL model for delayed coking processes (Tian et al 2012a,b). A Monte Carlo method was used to simulate the secondary reactions of the FCC of gasoline (Yang et al 2008) at the molecular level.…”

A Kinetic Model for Catalytic Cracking of Vacuum Gas Oil Using a Structure-oriented Lumping Method

“…Christensen et al (1999) developed a FCC process model by using the SOL method; it took 3,000 molecular species to describe feedstock composition with over 60 reaction rules. Yang et al (2008) combined the SOL method with a Monte Carlo method to simulate the second reactions of FCC gasoline.…”