Process Simulation Of Four-carbons Alkylation

Alkylated gasoline is also named technical iso-octane,as an outstanding reconciling oil,with excellent traits of low sulfur,light olefins and high octane number.According to alkylation unit of a refinery branch,the author accomplished the whole process simulation of both steady state model and dynamic model and tested the feasibility of the designed process,hoping to make some contribution to the development of domestic independent process package of four-carbons alkylation process.The design scale of the alkylation unit is 160,000 tons/year alkylated gasoline,however,it can actually produce 131,300 tons/year,owing to the limited amount of liquefied gas from MTBE unit and the content of alkene in it.This alkylation unit introduces the DuPont company’s process package from America,which consists of four parts:hydrofining section,alkylation reacting section,compressing and refrigerating section and product refining and fractionating section.On account of the restriction of corporate interests and Protect IP Act,we could hardly find this technology’s Process Flow Diagram and Piping&Instrument Diagram form document literature and the Internet,so the research project started from the construction of the technology process.On the basis of the process’s description in alkylation operating instruction from the refinery enterprise,the author drew a schematic diagram of the process by Computer Aided Design.Then the author utilized Unisim Design,a chemical process simulation software,to conduct the steady state simulation of the whole process,where PR-Twu thermodynamic method was adopted.Meanwhile,we gained the parameters of all streams based on the technology process and the parameters of apparatus.This part of the work was a test of the designed process’ feasibility as well.In order to complete the dynamic simulation of the whole process,firstly,the author sorted out all the components included in the process and the adaptive temperature range.Then the basic physical data of each component would be gained from the property database of Unisim Design.And the component which was not collected in the property database would be estimated in some proper methods.Next,the author studied the control schemes of the core apparatus,like the light hydrocarbon tower,the alkylation reactor,the compressor,the isobutane removal tower,the n-butane removal tower and so on.After the above work was done,the author drew the simulated process flowchart from the real and applied it on the Dynamic Simulation&Optimization platform(DSO)to conduct the dynamic simulation.In conclusion,the results were suitable with the designed.It not only proved the feasibility of the designed process,but also manifested the accuracy of the dynamic simulation.