Equilibrium properties of chain molecules in the isobaric-isothermal ensemble

مرکز و کتابخانه مطالعات اسلامی به زبان های اروپایی

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" Equilibrium properties of chain molecules in the isobaric-isothermal ensemble "
Saidu Muhammad Waziri

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	55524
Doc. No	:	TL25478
Call number	:	‭3290146‬
Main Entry	:	Saidu Muhammad Waziri
Title & Author	:	Equilibrium properties of chain molecules in the isobaric-isothermal ensemble\ Saidu Muhammad Waziri
College	:	King Fahd University of Petroleum and Minerals (Saudi Arabia)
Date	:	2007
Degree	:	Ph.D.
student score	:	2007
Page No	:	266
Abstract	:	The ability to predict equilibrium properties of chemical substances is vital to the design, optimization and operation of industrial chemical processes. Theoretical equations derived from models based on statistical-thermodynamics provide a useful means of predicting the equilibrium properties. In this dissertation, isothermal-isobaric ensemble (NPT) derived equations of state for modeling the pressure-volume-temperature (PVT) behavior and phase equilibrium properties of real chain molecules were developed using the principles of molecular thermodynamics. Using an NPT hard-sphere chain equation of state as a reference, an equation of state that is applicable to model chains of tangent and fused hard segments, and other molecular shapes such as spherocylinders and ellipsoids was derived. The newly proposed equation was found to give good prediction of literature simulation data, especially in the glassy state, where existing equations give very poor predictions. The equation was then developed further to predict the behavior of real chain molecules. The equation can account for chain stiffness, attractive contributions, and specific interactions. The performance of the equation in predicting the PVT behavior of real pure polymers and phase equilibrium data of polymer blend has been demonstrated. Modeling approach was applied to computationally screen ionic liquids for the desulfurization of diesel. A database consisting of 2270 ionic liquids was used for the study. For imidazolium-based ionic liquids, the result indicates that the solubility of diesel components follows the following trend: BT > DBT > 4-MDBT > 4,6-DMDBT > TMCH > Dodecane. The results also show that small anion size and large cation size favor the sulfur removal capacity of the ionic liquids. Experiments conducted on extractive desulfurization of model and commercial diesel using selected ionic liquids identified the capability of [bmpy][ms], [bmpy][bf4] and [omim][bf4] to give percentage sulfur removal of more than 50 % from model diesel in just a single extraction. The ionic liquid [bmpy][ms] was found to be the best among the ones used in the experiments. In a single extraction, it gives a percentage sulfur removal of 54.6 % and 20.1 % from model diesel and commercial diesel, respectively.
Subject	:	Applied sciences; Chemical engineering; 0542:Chemical engineering
Added Entry	:	King Fahd University of Petroleum and Minerals (Saudi Arabia)