8-叁等奖-摘要-华东理工大学-Z.G.X-甲醇气相催化脱水合成二甲醚工艺

AbstractIn the recent years, the dependence of china on imported petroleum is growing rapidly, which urges the important choice of energy strategy of developing the substitute or clean energy. As an alternative energy, Dimethyl-ether(DME) has its advantages and wins the close attention of plenty of countries in the world. The project designed by our group is the production of DME with the ability of 170 kt/a, in which the methanol dehydration method is applied. Factory or plant is located in Shanghai chemical industry area in the vicinity of Hangzhou Bay. There are feasibility report, initial design specification and process construction diagram included in our work.Ⅰ Process introduction1 Feedstock and plant locationThe main feedstock of this project is methanol, and methanol gas phase catalytic dehydration method is applied in the synthesis of DME because of the low temperature of bed and the scarce amount of by-reaction product.The plant is located in Shanghai chemical industry area in the vicinity of Hangzhou Bay.2 Brief description of the processMethanol gas phase catalytic dehydration method is applied in the synthesis of DME. The gasified methanol exchanges heat with the product coming out of reactor and then flows into the reactor carrying out the gas phase catalytic dehydration reaction. The product is cooled down by the recirculating water. the condensed material is separated, that the DME in gas phase is recycled by the absorption of methanol or methanol aqueous solution in a washing tower while the liquid or the coarse DME is sent for separation by rectification.3 Technical characteristic of the process(1)the process is comparatively simple and prompt, the operation is convenient andeffective.(2)the temperature of bed is low and the amount of by-reaction product is scarce(3)The entering temperature is low while the out tower temperature is high, the heatof the reaction producing the fuel-grade DME can be used in heating the reboiler instead of steam, and the steam pressure grade demands low.(4)The reaction heat recycles sufficiently, steam consumes little.(5)Reactor technology: single tube baffled reactor of methanol dehydration with agas-allot box(6)Modified catalyst :modified alumina catalyst for the synthesis of DME(7)DME rectification technology: the inner of the column adopts gauze packings andliquid distributor, bringing the advantages of large specific surface area, good liquid distribution, low pressure drop and high efficiency of mass and heat transfer.4 Detailed specification of the processMethanol is charged into the mixer by a feed pump, and then rectified by a distillation column .The unreacted methanol is recycled from the overhead product by a flash drum and blended with the gas mixture, while the remained light component is returned to the plant for methanol production. The pressure of the comparative pure methanol from the bottom boosts to about 0.9MPa by the feed pump. The methanol is heated to the boiling point via the preheater and vaporized by the gasified, exchanges heat with product from the reactor reaching the required temperature, then flows into the catalyst bed in the reactor and proceeds the gas phase catalytic dehydration reaction. Afterwards, the product DME with high purity is obtained through the separation of two distillation towers, and the methanol is recycled into the mixer. The noncondensable gas and coarse DME containing aromatic hydrocarbon vented may be used as fuel, and the process water can be used as complement water for boiler or cooling tower.Figure 1 Flow chart of the synthesis process of DMEFigure2 Process flow chartⅡ Plant design1 Overall layout of the general plant and manufacturing shopFigure4 Plant Layout Figure5 Facility LayoutAdopt Auto CAD to carry out the graphic design of the plant, and use Pro/E to draw up the three-dimensional effect picture.The plant is divided into four parts:product area,subsidiary product area, storage area and Chief living quarters.During the period of designing the layout of plant and manufacturing shop,we not only observe the safety regulations of the arrangement strictly, but also achieve the relatively proper and economical layout trying to cut down the consumption of the pipelines.Considering the heavy transportation load, weseparates the flow of the humans and vehicles.The general plant is surrounded by thegreen belt in order to isolate the plant area from the dangerous factors from the external world, ensuring the safety of production.Ⅲ Economical and technical indexSheet1 Economic balance sheetNO. Item Amount NO. Item Amount1 Production Capacity 5 Total Investment 233066400RMB DME 170000t/a 6 Yearly Sales Income 952000000RMB2 Device run-time 7200hr/h 7 Yearly Total Cost 648000000RMB8 Financial Appraisal Index3 Consumption of Materialand EnergyMethanol 412500t/a Profit Rate on Investment 45.45%Coal fuels 305000t/a Payback Period 2yearsElectricity 1100kwSteam 162000t/aCooling Water 1210t/a4 Area of Factory 30000 m2Ⅳ SummaryWe have accomplished process design and simulation via Aspen Plus,material and heat balance, heat integration via Aspen Pinch,equipment type selections, process flow diagram(PFD),process flow diagram with controlling point(piping and instrument diagram,PID), manufacturing shop arrangement diagram, layout diagram of the general plant,occupation safety and environmental protection,marketing and sales, investment and economic analysis.What's more,storage and transportation,electricity supply,utilities,fire fighting,water supply and drainage,andtelecommunication are also included.While,The detailed is introduced in the related document.。