Browsing by Author "Nurmi, Kasper"

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    Advanced cubic equation of state models
    (2020-08-18) Nurmi, Kasper; Kuitunen, Susanna; Ropponen, Artturi; Kemian tekniikan korkeakoulu; Alopaeus, Ville
    Phase equilibrium modelling plays a crucial part in chemical engineering. The chemical and oil industry handle systems with phase equilibriums of hundreds of compounds, which vary from being organic or inorganic having a polar or nonpolar part or being a small molecule to long and branched hydrocarbons. An accurate model in prevailing conditions is needed for successful and feasible design. A poor model can lead to over- or undersizing, which can cause a big safety issue and lead to significant value losses. Over the years a various models and methods have been proposed and in this thesis the volume-transalate Peng-Robinson (VTPR) model by Ahlers et al. is evaluated as a new promising solution. The aim of VTPR model is to predict more accurately saturated liquid densities, extend the scope further in the supercritical domain and enhance prediction of the asymmetric systems. VTPR model features volume translation to correct systematic error in volume, Gibbs free energy with binary interaction parameters and temperature dependent pure component specific alpha function. In this thesis's applied part VTPR model alpha function and its parameters were evaluated comprehensively. Alpha function parameter regressions were carried out with two separate methods, which both utilize Aspen Plus process simulator and RStudio R programming environment. This thesis points out that VTPR model can accurately describe various pure component and mixture properties in varying conditions. The biggest weakness was found to be specific heat capacity prediction where the VTPR model failed in many cases.
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    Väliseinälliset tislauskolonnit
    (2017-05-22) Nurmi, Kasper; Jakobsson, Kaj; Kemiantekniikan korkeakoulu; Rautkari, Lauri