Research On Modeling Method Of Distillation Tower Based On Special Pseudo-components

Distillation is the most commonly used separation device in refinery engineering.It has a characteristics of large volume and high energy consumption and its operation involves mass transfer and heat transfer process of vapor-liquid equilibrium in a highly complex spatial distribution and it’s modeling is difficult.Based on the above,the modeling and operation optimization of the distillation tower is still a challenge,even the achievements in the distillation tower are great since 1950.To solve the problems that properties of conventional pseudocomponents(CPCs)vary for different oils and the convenient dynamic simulation of operations of time-varying feed(feed switching between different oils or mixing multiple oils as feed)in petroleum distillations,petroleum oils and their distillation products are characterized with special pseudocomponents(SPCs).The contents of this paper are:(1)Oil characterization based on SPCs and CPCs are described;Mixed SPCs into CPCs with different light-heavy mixing rule to validate the equivalence between SPCs and CPCs in enthalpy and vapor pressure;Verified the correct of vapor-liquid equilibrium model based on SPCs at low pressure by comparing the flash model based on SPCs and CPCs for various oils.(2)This two kinds of crude oil characterization methods are combined with the equilibrium stage model with a shortcut gas flow to model a distillation tower;To calculate this two models with the fourth order Runge-Kutta;In comparison with this two models,the SPCs is superior to CPCs in distillation tower modeling with time-varying feed.