Research And Application Of Distillationmembrane Separation Integrated Process Based On GP Programming

In this paper,an extended distillation-membrane separation integration solution strategy based on genetic programming algorithm（GP）is established.According to the characteristics and separation requirements of various industrial azeotropic systems,the optimal distillation-membrane separation integration process and its parameters can be automatically solved on the basis of matching appropriate membrane separation types and membrane materials,and the application of the comprehensive strategy is studied.The integrated solution strategy of GP based extended distillation-membrane separation includes the definition of extended chemical node,the generation of chemical professional population,the calculation of individual fitness,the improvement and perfection of the definition of evolutionary operation and algorithm termination criteria.On this basis,continue to use the upper limit price（Pmax）method of unit membrane area theory to predict membrane cost,and the general laws of chemical production are reasonably implanted into GP algorithm to ensure the rationality and applicability of the comprehensive solution strategy for chemical process.The extended GP comprehensive strategy established above is used to focus on the integrated research of distillation-membrane separation for a large number of new membrane types and membrane materials that are still in the research stage.The theory of membrane segmentation and reorganization is proposed.Through the random series and parallel combination of small membrane modules,multiple medium membrane modules with different feed concentrations are formed,and then all medium membranes are integrated as membrane separation modules with material concentration gradient.The membrane separation process described by this kind of solution method is more practical.Two typical azeotropic systems（isopropanol-water and acetonitrile-water）are calculated to verify the membrane segmentation and reorganization theory.The results show that the optimal integration process parameters obtained based on the GP solution strategy of membrane segmentation and reorganization theory fit the performance that the actual flow through membrane,and the membrane parameters are more applicable.Therefore,the application of membrane segmentation and reorganization theory is reasonable.On this basis,the GP comprehensive solution strategy is used to study the gasoline desulfurization problem which is an industrial hot spot.The integrated distillationmembrane separation method is used for gasoline desulfurization,at the same time,the issue of carbon emissions has been concerned.The optimal design of different integrated processes for gasoline desulfurization from Chinese standard IV to Chinese standard V is discussed,and the economy of integrated processes under each standard is studied.The results show that the membrane area has no obvious growth trend when the separation requirement from Chinese standard IV to Chinese standard V,and the corresponding Pmax is improved.It shows that the integrated distillation-membrane separation process is more economical when the desulfurization requirements from Chinese standard IV to Chinese standard V.In addition,it can be seen from the carbon emission that the integrated distillation-membrane separation process has more advantages than the conventional extractive distillation process.The effects of Polyether block polyamide（PEBAX）membrane and Polydimethylsiloxane（PDMS）membrane’s modification on the integrated distillationmembrane separation process are studied.For the calculation and prediction of membrane cost parameter Pmax,the extraction process with lower carbon emission（extraction column + distillation column）is constructed.Through comparison,the ionic liquid extraction process with lower TAC value and less carbon emission is selected.Taking these TAC values as the calculation target of Pmax,the parameters and separation performance of PEBAX membrane,PDMS membrane and their modified membranes in the optimal integration process under various feed conditions are analyzed.The results show that the membrane separation performance will be improved by reducing the permeation flux and increasing the separation factor or reducing the separation factor and increasing the permeation flux,However,it is inefficient to pursue the improvement of one attribute and ignore another attribute for the improvement of the overall performance of the membrane.The extended GP comprehensive strategy established in this paper can effectively solve the industrial separation problem,and provide some guidance for industrial production through important indicators such as carbon emission.In addition,the evaluation of membrane separation performance and the influence of modification direction can provide a reference for the future industrialization of membrane.The above conclusions can provide a strong basis for the separation of industrial hot spots.