Optimization And Improvement For Methanol Distillation Process And Research On Compound Tray's Design Model

With the development of economy and the increasingly tense energy situation,the energy-saving of chemical process become more and more attractive.The optimization of chemical process includes both the improvement of technology and green chemical equipment.The methanol distillation process is improved and optimized from the aspects of technology and equipment.An annual output of 320000 tons of methanol distillation process flow is simulated and optimized by using commercial simulation software Aspen plus.According to the method of characteristics and shortcoming analysis,a heat-pump process is purposed based on the traditional methanol distillation.In this process,the method of heat-pump is used for pressurized distillation column and normal pressure distillation column to save energy.Then an optimal operating condition was obtained by analyzing the consumption of public engineering of the heat-pump methanol distillation.In the proposed process,61%public engineering of heat and 51%public engineering cooling capacity are saved,while the electricity consumption increases 4814 kW/h,the total operating expense decreases by 30.088%.Structured packing has been widely used in methanol distillation process because of the good mass transfer performance.Structured packing can meet the requirements of the production capacity and the purity of methanol.However,compared with the tray,structured packing has a higher cost and a lower flux.Based on the above analysis,T/P type compound tray is of potential for methanol distillation process by combining the high efficiency of structured packing with the high flux of tray.The influence of the large spacing between the dual-tray and packing on the hydrodynamic performance of the T/P type compound tray is investigated by experiments in this thesis.The experiments were performed in an organic glass column with an inner diameter of 600 mm.The dual-trays with open area of 25%,20%,2.3%based on the tray bubbling area and with the hole diameter of 8mm are concerned,packings are Mellapak350Y,250Y with a thickness of 100mm.The spacing of installation are 0 mm,7.6 mm,15 mm,22 mm,30 mm,40 mm.Based on the experimental results,it was concluded that large installation have a lower dry tray pressure drop compared to small installation.Within a certain range of F-factors,the wet tray pressure drop of each installation has a similar growth trend.The flood points of installation spacing of 15mm,22 mm,30 mm and 40 mm are lower than that with 0 mm,7.6 mm.The related independent dual-tray and the structured packing have also been performed.Based on the experimental results,it was concluded that the flooding point of T/P type compound tray is determined by the packing at large open area,while at small open area,the dual-tray is the key factor.Before the flooding point,the proportion of interaction to compound tray's pressure drop is about 0.36².8%under the water spray density of 10 m³/?m²·h?and it will be within the limits of±8%under the water spray density of 20 m³/?m²·h?and 30 m³/?m²·h?.The proportions of dual-flow tray and packing show a shift in the trend.According to the experiment,a preliminary design model of T/P type compound tray is proposed:?P_{T/P type compound tray}=K₁??P_dual-tray+K₂??P_packing?K₁,K₂:correction factor?...