CA Modeling And Simulation Of Mesoscale Process For Fe-based Catalyst Preparation By Precipitation Method

The preparation of Fe-based catalysts has been an important issue studied by many scholars.Fe-based catalysts are mainly used in the synthesis of petroleum by Fischer-Tropsch reaction.The activity and microstructure of the catalysts have a tremendous influence on the purity of synthetic petroleum.This paper mainly focuses on the mesoscale behavior of primary particles aggregated into secondary particles during the preparation of Fe-based catalysts by precipitation method.Combining with the extended DLVO theory and integrating the effects of van der Waals forces,electrostatic forces and interface polarity interaction forces into the rules of the cellular automaton,a cellular automaton model for the aggregation behavior of nanoparticles in the preparation of Fe-based catalysts is constructed.And the numerical simulation was also proceed.This paper is mainly composed of the following five parts:In the first chapter,the background of multi-scale problems and cellular automata in the preparation of Fe-based catalysts are introduced.And the main study of the research are presented.Furthermore,the main contents and results of this paper are pointed out.In the second chapter,the main components and basic principles of cellular automata are introduced.And the mathematical model of the solute-dissolved cellular automata is established.Subsequently,the influence of temperature on the solute dissolution is discussed.Then the simulation results are analyzed by means of average displacement.Furthermore,a mathematical model of cellular automata for solution stratification is established.And the effect of relative gravity on the stratification results is also considered.The simulation results of the two processes are consistent with the results of reality case,which shows the effectiveness and rationality of the cellular automata model.In the third chapter,the cellular automata model of the secondary particle generated by primary particles in the preparation of Fe-based catalysts is build.Firstly,the law of particle aggregation is discussed based on EDLVO theory.And the relationship between the potential energy of particles,the species of particles and the distance of particles is studied.Combining the moving probability,the connection probability and the fracture probability with EDLVO theory,the next step motion rule of the particle is given.Therefore,the cellular automaton model of primary particle aggregation for Fe-based catalysts is constructed.In the fourth chapter,according to the CA model of the mesoscale process,the concrete calculation steps and flow charts of CA simulation are given,which are implemented by Java program.The results are compared with the experimental results to verify the effectiveness of the method.Finally,the influence of the probability of the CA simulation results is studied.The last chapter,the research content and innovation of this paper is summarized,and the next research direction is also pointed out.