Study On Rectisol Process Simulation

Rectisol has been widely used in coal chemical industry with the coal as raw material.After the introduction of the technology in China,many research institutes and engineering companies have carried out a great deal of research on it.In the study of Rectisol process simulation,the equilibrium model is widely used because of its convenience,simplicity,intuition and easy convergence advantages.But this model introduces the experience parameters such as stage efficiency,height equivalent of theoretical plate（HETP）,and so on,however,there are no formulas or methods for predicting and calculating these parameters,therefore the application of equilibrium model is restricted and most of the time equilibrium model needs to be modified.By combing the process design package data of Rectisol from a domestic coal chemical project,relying on Aspen Plus process simulation software,and introducing the PSRK and NRTL equilibrium models to the calculation,in order to make the calculation results more accurate,the parameters in some physical methods will be modified.By comparing the simulation results,the model with the closest calculation result to the design data is selected inorder to provide the data support for the optimization of operation.The modified model is used to do the sensitivity analysis of stripping nitrogen gas consumption,the flow and concentration of lean methanol in absorber,the optimization of operation parameters is also proposed.Through the research,it is found that the choice of physical property method has great influence on the calculation results.The calculation results of the PSRK method are accurate and can be used as the basis for the simulation of Rectisol.The data regression of binary interaction parameters by PSRK method,and using of Wanger equation to replace the Antoine equation to calculate the saturated vapor pressure of methanol,are helpful to improve the accuracy of calculation.At the same time,the temperature compensation method can effectively eliminate the deviation of the CO₂ solution heat between simulation and actual value,which can improve the accuracy of calculation either.