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Development And Application Of Group Contribution For The Equation Of State Of Square-well Chain-like Fluid

Posted on:2016-03-07Degree:MasterType:Thesis
Country:ChinaCandidate:C H WangFull Text:PDF
GTID:2191330461961324Subject:Chemical Engineering
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The thermal physical properties and phase equilibrium data of fluid is very important for chemical process design, simulation and optimization, etc. Modeling of thermodynamic properties and phase equilibrium data for fluid based on equation of state (EOS) plays an important role in the production of chemical industry, optimization of operating conditions and technological process. It is of great significance of developing equation of state with predicted function to expand the application of theoretical model in wide range when lack of experimental data. A new group contribution for the equation of state for the square-well chain-like fluid (GC-SWCF) based on group contribution and equation of state for square-well chain-like fluid with variable range (SWCF-VR) was proposed. In this paper, in order to develop the prediction function of equation of state, the model parameters of equation of state was obtained by the GC pure compounds parameters.Firstly, the group parameters of 8 kinds of organic groups and 16 kinds of metal groups are obtained from a great quantity of liquid density data of various pure organic compounds and molten metals. These group parameters laid the foundation of prediction of thermodynamic properties of compounds. On this basis, the GC-SWCF equation of state was used to predict the density of organic compounds such as 1-alkanes and 1-alcohol (C>10) with overall average deviations (AAD%) of 2.39% and 2.03%, respectively. On the other hand, the GC-SWCF equation of state can satisfactorily predict the density of liquid metals in wide range of temperature and pressure. The overall average deviations were 0.16%. Moreover, the vaporization of enthalpies of several olefin and ketone estimated by GC-SWCF equation of state also close to experimental ones. The results show that the GC-SWCF equation of state can satisfactorily predict the vaporization of enthalpies of organic compounds when away from the critical point. The overall average deviations are 4.80% and 4.88%, respectively.With one independent-temperature binary adjustable parameter, the satisfactory binary density properties for alkane-alkane and alkane-alcohol mixtures are obtained in wide range of temperature. The overall average deviations are 0.59% and 1.16%, respectively. The GC-SWCF equation of state can also satisfactorily predict the density of alloys by using the binary interaction adjustable parameter. Coupled with one-fluid mixing rule, the vapor-liquid equilibria (VLE) for organic mixtures are studied. The results show that GC-SWCF equation of state can well predict the vapor-liquid equiliria of binary organic compounds when molecular structure is simple and similar. And the overall average deviations of temperature and pressure are 1.84K and 3.20kPa, respectively. The overall average deviation of vapor phase is 1.98%. However, the slightly larger deviations between correlated and experimental results for associating fluid were observed as a result of the association between molecules. But it does represent the experimental phenomena. So as a whole, the prediction results of GC-SWCF model are satisfactory.
Keywords/Search Tags:group contribution, equation of state, density, vaporization of enthalpy, vapor-liquid equilibria
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