Analysis of chromatographic theories and thermodynamics calculation procedure
- Authors: Muzenda, Edison
- Date: 2012
- Subjects: Band broadening , Retention volume , Chromatography
- Type: Article
- Identifier: uj:4663 , ISBN 978-93-82242-16-1 , http://hdl.handle.net/10210/10038
- Description: This paper presents the development of chromatography, two mathematical methods for describing chromatographic phenomena, band broadening processes as well as the procedure for retention volume measurement and calculation. The plate and the rate theories for gas chromatographic phenomena are comprehensively discussed. The reduction of infinite dilution activity coefficients from retention data is explained. While the rate theory can predict the influence of various factors on column performance, the plate theory is more useful in the calculation of thermodynamic properties such as infinite dilution activity coefficients, enthalpy and entropy of mixtures.
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Chromatographic detectors and column holdup for organics-PDMS systems
- Authors: Muzenda, Edison
- Date: 2012
- Subjects: Polydimethylsiloxane , Column hold-ups , Gas chromatographic detectors
- Type: Article
- Identifier: uj:4688 , ISBN 978-93-82242-16-1 , http://hdl.handle.net/10210/10477
- Description: Gas chromatographic detector types and application, as well carrier gas flow rate and column hold-up measurements are discussed in this paper. The flame ionization and hot wire detectors are discussed in detail. The measurement of carrier gas flow rate using a soap film bubble flow meter is explained. Column hold-ups for 4 poly(dimethylsiloxane) packed columns were measured using the homologous series method.
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Effect of pressure, temperature and steam to carbon ratio on steam reforming of vegetable oils : simulation study
- Authors: Jalama, Kalala
- Date: 2012
- Subjects: Vegetable oil , Steam reforming
- Type: Article
- Identifier: uj:6029 , ISBN 978-93-82242-16-1 , http://hdl.handle.net/10210/10050
- Description: Please refer to full text to view abstract
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Influence of temperature and molecular structure on organics-biodiesel interactions using group contribution methods
- Authors: Scheepers, Jacques J. , Muzenda, Edison , Belaid, Mohamed
- Date: 2012
- Subjects: Group contribution method , Phase equilibrium , Solubility , Volatile organic compounds , Absorption , Activity coefficients
- Type: Article
- Identifier: uj:4672 , ISBN 978-93-82242-16-1 , http://hdl.handle.net/10210/10437
- Description: Resulting from the trend of increasingly stringent environmental legislation, the drive to secure environmentally friendly absorption solvents has gained much impetus in recent times. In order to design and operate separation processes units, it is essential that the engineer has accurate and reliable knowledge of the phase equilibrium behaviour of the system in question. Since obtaining experimental data on the system can be time-consuming, the use of thermodynamic models is often useful in obtaining preliminary design and feasibility study information. This work examines the suitability of biodiesel (particularly the constituents methyl palmitate and methyl linolenate) as an absorbent solvent for the recovery of volatile organic compounds (VOCs) from waste process gas streams. In particular, activity coefficients were measured in the dilute region in an attempt to predict the effects of molecular structure and temperature on the solubility of the VOCs in the methyl esters under study. The group contribution methods UNIFAC and Modified UNIFAC Dortmund, set up on Microsoft Excel spreadsheets, were used to predict the required phase equilibrium at infinite dilution. The results obtaine
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