Study On The Expressions And Their Applications Of Relative Volatility And Clapeyron Equation With Inlfuence Of External Electric And Magnetic Fields

Thermodynamics is a macro theory about thermal motions, and it is reliable anduniversal for its research method is based on the logical deduction according to the basic lawssummarized up from experiences. Phase transition is widely exist in the nature andengineering and has important applications in chemical detach, energy store, environmentprotection, medicine pharmacy, material preparation and so on. We study phase transitionfrom heat diffusion, fluid dynamics and chemical potential at present. With the developmentof electromagnetic technology, more and more study focus on how to change thermodynamicproperties of the system by using electric or magnetic ifeld. The physical signiifcance ofrelative volatility is the reflection of the difference between two components’ relative contentin two phases, which is mean to the complexity of separation. During the chemical separationoperations, distillation is one of the most important operations. People usually pay mostattention to how to reduce the energy wastage and enhance the production eiffciency.Based on the classical thermodynamics, using the expressions of chemical potentialunder electric ifeld or magnetic ifeld，combining the condition of phase equilibrium,expressions of ideal dilute solution’s relative volatility including the inlfuences of externalelectric ifeld or magnetic ifeld was derived. With the expression of relative volatility under theinfluences of electric ifeld，it can forecast on the same system under the same temperature andpressure, the larger intensity of its electric ifeld，the bigger transform of relative volatility itwill be. While the different system under the same temperature and electric ifeld，the biggergap between two components’ dielectric constants, the bigger gap between two components’mole polarization can, the bigger transform of relative volatility it will be. With thegeneralized expression of relative volatility under the influences of magnetic ifeld，it canforecast on the same system under the same temperature and pressure, the larger intensity ofits magnetic ifeld，the bigger transform of relative volatility it will be. While the differentsystem under the same temperature and magnetic ifeld，the bigger gap between twocomponents’ magnetic permeability, the bigger gap between two components’ molemagnetization can, the bigger transform of relative volatility it will be. Using the generalizedexpression of relative volatility under the influences of electric ifeld to forecast the system ofethanol and water, the system of benzene and toluene, the system of benzene and p-xylene, itifnd that the biggest transform of relative volatility will be under the106?107V/m electricifeld, which is the same to part of the experiments. Under the error of10%，this theorymatches up the experiment value. Therefore, the generalized expression of chemical potential under electric ifeld or magnetic ifeld would play an important guidance for the study on howto improve the separation of distillation operation.Clapeyron equation gives a quantitative description on the dependencies of temperatureand pressure about any pure substance’s two phase equilibrium, it plays an important role inthermodynamic engineering. Using the functions of thermodynamic and the polarizationeffect or magnetization effect of electric or magnetic ifeld, a generalized expression ofClapeyron equation including the inlfuences of electromagnetic ifeld was derived. Put thegeneralized expression into the use on gas-liquid phase transition, gas-solid phase transitionand solid-liquid phase transition, it could ifnd the relationship among temperature, pressureand phase change enthalpy with the inlfuences of electromagnetic ifeld. This theory couldgive a more expression on the dependencies of temperature and pressure about any puresubstance’s two phase equilibrium, it plays an important guidance for the study on puresubstance’s phase transition of thermodynamic.