Dividing wall column(DWC)is shown to be energy efficient compared to conventional column sequence for multi components separation,which is used for olefin separation in fluidization methanol to propylene process in th...Dividing wall column(DWC)is shown to be energy efficient compared to conventional column sequence for multi components separation,which is used for olefin separation in fluidization methanol to propylene process in the present work.Detailed design for pilot DWC was performed and five control structures,i.e.composition control(CC),temperature control(TC),composition-temperature control(CC-TC),temperature difference control(TDC),double temperature difference control(DTDC)were proposed to circumvent feed disturbance.Sensitivity analysis and singular value decomposition(SVD)were used as criterion to select the controlled temperature locations in TC,CC-TC,TDC and DTDC control loops.The steady simulation result demonstrates that 25.7% and 30.2% duty can be saved for condenser and reboiler by substituting conventional column sequence with DWC,respectively.As for control structure selection,TC and TDC perform better than other three control schemes with smaller maximum deviation and shorter settling time.展开更多
Soft computing tools in the form of combination of multiple nonlinear regression and M5′ model tree were used for estimation of overtopping rate at the vertical coastal structures. For reliable and precise estimation...Soft computing tools in the form of combination of multiple nonlinear regression and M5′ model tree were used for estimation of overtopping rate at the vertical coastal structures. For reliable and precise estimation of overtopping rate, the experimental data available in the database CLASH were used. The dimensionless overtopping rate was estimated in terms of conventional dimensionless parameters including the relative crest freeboard Rc/Hs, seabed slope tanθ, deep water wave steepness S（om）, surf similarity ξ（om） and local relative water depth ht/Hs. The accuracy of the new model was compared with other existing models and also evaluated with some field measurements. The results indicated that the model presented in this paper is more accurate than other existing models. With statistical parameters, it is shown that the accuracy of predictions in the new model is better than that of other models.展开更多
A two-dimensional(2-D) finite element(FE) model was developed to analyze the deformation and stress of embankment on soft ground due to widening with different treatment techniques.It is found that the embankment wide...A two-dimensional(2-D) finite element(FE) model was developed to analyze the deformation and stress of embankment on soft ground due to widening with different treatment techniques.It is found that the embankment widening induces transverse gradient change due to differential settlements and horizontal outward movements at the shoulder of the existing embankment.Embankment widening also increases the shear stress along the slope of the existing embankment,especially at the foot of slope.The failure potential due to embankment widening may increase with the increase of widening width when the widening width is smaller than 8.5 m,but may decrease with the increase of widening width as the widening width is greater than 8.5 m.The effectiveness of four ground and embankment treatment techniques,including geosynthetic reinforcement,light-weight embankment,deep mixed columns,and separating wall were compared.The results indicate that these treatments reduce the differential settlements and improve the stability.The light-weight embankment has the most effectiveness among four treatments.By using the fly-ash backfill material in widening,the transverse gradient change decreases from 0.5%-1.3% to 0.26%-0.8% and the maximum horizontal displacement decreases from 2.76 cm to 1.44 cm.展开更多
基金Supported by Open Research Project of State Key Laboratory of Chemical Engineering(Grant No.SKL-Ch E-16B06)
文摘Dividing wall column(DWC)is shown to be energy efficient compared to conventional column sequence for multi components separation,which is used for olefin separation in fluidization methanol to propylene process in the present work.Detailed design for pilot DWC was performed and five control structures,i.e.composition control(CC),temperature control(TC),composition-temperature control(CC-TC),temperature difference control(TDC),double temperature difference control(DTDC)were proposed to circumvent feed disturbance.Sensitivity analysis and singular value decomposition(SVD)were used as criterion to select the controlled temperature locations in TC,CC-TC,TDC and DTDC control loops.The steady simulation result demonstrates that 25.7% and 30.2% duty can be saved for condenser and reboiler by substituting conventional column sequence with DWC,respectively.As for control structure selection,TC and TDC perform better than other three control schemes with smaller maximum deviation and shorter settling time.
文摘Soft computing tools in the form of combination of multiple nonlinear regression and M5′ model tree were used for estimation of overtopping rate at the vertical coastal structures. For reliable and precise estimation of overtopping rate, the experimental data available in the database CLASH were used. The dimensionless overtopping rate was estimated in terms of conventional dimensionless parameters including the relative crest freeboard Rc/Hs, seabed slope tanθ, deep water wave steepness S（om）, surf similarity ξ（om） and local relative water depth ht/Hs. The accuracy of the new model was compared with other existing models and also evaluated with some field measurements. The results indicated that the model presented in this paper is more accurate than other existing models. With statistical parameters, it is shown that the accuracy of predictions in the new model is better than that of other models.
文摘A two-dimensional(2-D) finite element(FE) model was developed to analyze the deformation and stress of embankment on soft ground due to widening with different treatment techniques.It is found that the embankment widening induces transverse gradient change due to differential settlements and horizontal outward movements at the shoulder of the existing embankment.Embankment widening also increases the shear stress along the slope of the existing embankment,especially at the foot of slope.The failure potential due to embankment widening may increase with the increase of widening width when the widening width is smaller than 8.5 m,but may decrease with the increase of widening width as the widening width is greater than 8.5 m.The effectiveness of four ground and embankment treatment techniques,including geosynthetic reinforcement,light-weight embankment,deep mixed columns,and separating wall were compared.The results indicate that these treatments reduce the differential settlements and improve the stability.The light-weight embankment has the most effectiveness among four treatments.By using the fly-ash backfill material in widening,the transverse gradient change decreases from 0.5%-1.3% to 0.26%-0.8% and the maximum horizontal displacement decreases from 2.76 cm to 1.44 cm.
