EQ-COMP : The VLE Application
Vapor-Liquid Equilibrium properties of hydrocarbon mixtures play an essential part in designing of flash chambers and distillation equipments like distillation colums in oil refineries and gas processing plants like LPG plants and LNG liquefaction and gasification plants. Also VLE properties like dew points and retrograde compositions are necessary for nicely simulation of oil and gas wells. Prediction of these properties can be helpful in simulating planetary atmosphere of other heavenly bodies which is composed of varying proportions of a variety of hydrocarbons like Methane, Ethane and Propane and some inorganic gases like H2S, CO2 and N2. Vapor-Liquid equilibrium properties for binary mixtures are relatively less complicated to calculate but multicomponent vapor-liquid equilibrium properties call for complex calculations involving complex equations. These calculations can only be executed making use of newest computer systems. These calculations additional need very complicated computer programs for automating them so that appropriate values are calculated at just the click of a button.
EQ-COMP is a very complicated combination of a variety of macros written in MS Excel employing Visual Basic for Application programming language for calculating multicomponent vapor-liquid equilibrium properties and automating the procedure involved so that the calculations can be executed at the click of a button. It is valuable in locating out vapor-liquid equilibrium properties for a hydrocarbon mixture for practically any composition with a lot more than one hundred attainable elements. Its different modules can be utilised to locate out bubble point temperature, dew point temperature, phase envelop and two phase composition even in retrograde region and for compositions involving high proportions of inorganic gases.
The preferred technique for calculating multicomponent VLE properties for non-polar hydrocarbon mixtures entails use of Peng-Robinson cubic equation of state. EQ-COMP uses the identical strategy for calculating VLE properties of multicomponent hydrocarbon mixtures. In designing of EQ-COMP, trends of a variety of phase envelop curves for diverse compositions developed using 1st principles have been meticulously studied and generalized to match other compositions. As EQ-COMP uses initial principles and regular calculation tools like MS excel for carrying out the calculations so creating outcomes may possibly take as long as an hour but the chances of the results being incorrect beneath the preview of Peng-Robinson cubic equation of state is virtually nil. Binary interaction parameters are necessary to be incorporated in the calculations involving inorganic gases like nitrogen, hydrogen sulphide and carbon dioxide for right benefits but in absence of appropriate values of these parameters, the same are not used in calculation of final results.
The phase envelop result for a standard natural gas composition calculated utilizing EQ-COMP is offered below:
Methane : 70 %, Ethane : 15 %, Propane : 8 %
i-Butane : two %, n-Butane : 2 %, n-Pentane : 1 %
two Methyl Butane : 1 %, n-Hexane : 1 %
The phase envelop result for a non-standard composition with high proportion of inorganic gases utilizing EQ-COMP is offered below:
Methane : 10%,n-Hexane : ten%, n-Heptane : ten%
n-Octane : 20 %, Nitrogen : 50 %