The Research And Simulation Of Precooling Process Of Air Separation System Based On MWorks

With the development of national economy, the lower energy and the super device ofthe air separation equipments is the main trend. As an important part of the air separationequipment, the process organization and the performance of the equipment of theprecooling process has a great influence on the whole air separation unit, so the precoolingprocess has also become a hot research. And as two core equipments of the precoolingprocess, air-cooling tower and water-cooling tower are the importment research focus.Around this theme, the work of this thesis is mainly composed of the following severalparts.Based on the organization form of precooling process, this paper introduces thedifferent organization forms of precooling process as the different demand for nitrogen andoxygen. Through analysis the research achievements of predecessors, this thesis analysisthe three kinds of heat and mass transfer theory model, and build the heat and mass transfertheory model which is suitable for air-cooling tower and water-cooling tower. Thesimulation program is written based on MWorks, and use the unified modelinglanguage-Modelica. MWorks is not only reducing the time of programming, but alsoimprove the expandability, convenience and readability of the package. By comparing otherliterature data and the simulation results, we can see the reliability and effectiveness of theproposed method.And in this thesis another mathematical model is put forward, which is includeconservation of energy, heat transfer rate equation and the mass transfer rate equation inthis Infinitesimal section. This model ont only eliminates the constant assumption of gasand water property of the Merkel model, which make the model accurate, but also candisplay the tower temperature and humidity change as the direction of flowing. Andthrough using the simulation program, a120000Nm3/h air separation unit is calculation and analyzed. And when the working conditions are changing, the parameter of thetemperature and the humidity of the air-cooling tower and water-cooling tower issimulation. Through the analysis of parameter changes, this thesis puts forward somefeasible suggestions.