The Simulation And Analysis Of The Process Cryogenic Air Separation

In recent years,as the economy develops rapidly in the whole world,the demand of oxygen,nitrogen and argon gas in all industries is also increasing.Air separation is the process of industrial gases which produces high purity oxygen,nitrogen,argon and other important industrial productions.In the air separation process,although the cost of raw material is very low,power consumption is much bigger.With the trend of large-scale air separation equipment,the enterprises pay more and more attention to how to reduce the production cost.And the low temperature separation method that separates different components on the basis of different boiling point of the oxygen,nitrogen,argon,which is commonly used in diversity of air separation process.Air separation unit as a variety of products output device,analysis of energy consumption of air separation products and energy consumption of variable load adjustment of product are key factors to reduce the energy consumption of air separation device,so the optimal design and real time optimization operation is great significant to reducing consumption of the entire unit.Based on the industrial application background of a state-owned 28000Nm~3/h air separation unit,five kinds of load conditions(80%,90%,100%,110%,120%)have been analyzed in variable condition according to Aspen Plus simulation software process.In this paper,the contents and conclusions have been resulted as follows:(1)The Aspen Plus process simulation software was used for air separation device of the whole system and the model that can reflect the reality of the factory was established.What's more,the optimized results of air separation unit,each tower diameter,and other important process parameters were obtained through optimized calculation.(2)Aspen Energy Analyzer software was used for the matching of logistics and logistics,logistics and matching between cold and hot utility,and finally through optimization,the optimal scheme is obtained.What's more,the sensitivity analysis of Aspen Plus was applied to optimize the core of the air separation column under the tower,the optimized result was given priority to rectify the tower pressure 0.56 MPa,feed temperature of 173.3oC,liquid nitrogen at the top of the column can amount to 1615kmol/h,liquid feed position for 33 pieces of plate.(the unit operation models and correlation methods established in this paper are reliable and reasonable for the results of air separation unit,and the optimization scheme for the actual operation also has certain guiding significance.)(3)Five kinds of operation mode analysis of distillation process of the main column was used for the pressure,feed temperature,feed position,feed flow rate on the influence of the distillation unit,and under the variable condition,the heat exchanger changes of the was also inspected.Analysis results under different load conditions,optimize production operation had theoretical guidance value.Simulation results show that the built of Aspen Plus process simulation can well express the actual device of production data.