M.H. Joshipura

Comparing Four Compound-specific Cohesion Factor Relationships for Soave–Redlich–Kwong Equation of State

Abstract The approach described in one of our previous papers (Jr. Taiwan Inst. Chem. Eng., 41, pp. 570–578, 2010) was applied to the Soave–Redlich–Kwong equation of state to develop compound-specific parameters for four different types of cohesion factor models. Compound-specific parameters for nearly 300 compounds are listed in the paper and can be utilized for the modelling of phase equilibrium of the mixtures of these compounds. Performance of the models was compared based on the accuracy in predicting various pure compound properties as well as vapour liquid equilibrium of binary systems. The modified Trebble Bishnoi (mGAS) type of cohesion factor model emerged as the best amongst the compared models. Generalization of compound-specific models was also done. These expressions would be useful in the absence of compound-specific parameters.

New Analytical Expression for the Prediction of Vapour Pressures of Ionic Liquids

Abstract Ionic liquids (IL), considered as green solvents, are useful in different industrial applications. Vapour pressure is one of the key properties of IL for designing different processes. Recently, the zero pressure fugacity approach was proposed to predict the vapour pressures of IL using cubic equations of state. In the present work, this approach was improved by fitting the vapour pressure data of ten ILs using six different cohesion factor models. New analytical expressions are proposed in the present work for predicting vapour pressure of IL using acentric factor and Mass Connectivity Index. It was shown that one of the proposed models (Model J) predicts vapour pressure with global %AAD of 7.3%. The model compared with the models based on COSMO-RS theory and PC SAFT-equation of state (EOS), and it was found that the proposed models work well compared to others. It is shown that the proposed models predict vapour pressure with greater accuracy and consistency.

Development of Compound Specific Cohesion Function Relationship for SRK Equation of State

Abstract Chemical industries have undergone a paradigm shift in the designing process in the last decade, and most of them now rely on process simulators for designing and optimisation. Simulators are heavily dependent on thermodynamic models for the proper outcome of any simulation problem, in general, and phase equilibrium problem, in particular. Equations of state (EOS) have gained wide popularity due to their simplicity. Cubic equations of state (CEOS) can very accurately predict various thermophysical properties with minimum requirement of data. One of the key factors for obtaining accurate results from CEOS is its temperature dependency of cohesion factor relationship. In the present study, a new compound specific cohesion factor relationship is proposed for the Soave Redlich Kwong (SRK) EOS. The new model was compared with the original SRK EOS and its modified versions for accuracy in estimating vapour pressure for a large number of compounds representing various classes of families. It was found that the new relationship works better for almost all the families considered, especially, improving the vapour pressure prediction in the range of reduced temperature below 0.7.

Thermodynamic analysis and heat integration for hydrogen production from bio-butanol for SOFC application: Steam reforming vs. autothermal reforming

ABSTRACT Thermodynamic analysis of hydrogen production by steam reforming and autothermal reforming of bio-butanol was investigated for solid oxide fuel cell applications. The effects of reformer operating conditions, e.g., reformer temperature, steam to carbon molar ratio, and oxygen to carbon molar ratio, were investigated with the objective to maximize hydrogen production and to reduce utility requirements of the process and based on which favorable conditions of reformer were proposed. Process flow diagram for steam reforming and autothermal reforming integrated with solid oxide fuel cell was developed. Heat integration with pinch analysis method was carried out for both the processes at favorable reformer conditions. Power generation, electrical efficiency, useful energy for co-generation application, and utility requirements for both the processes were compared.