Thesis (MIng) --Stellenbosch University, 1999. / ENGLISH ABSTRACT: A method was developed at the Atomic Energy Corporation of South Africa (AEC) for the
plasma based production of tetrafluoroethylene (TFE). The process involves the feeding of
carbon particles into a direct-current CF4 plasma. The resultant plasma gas is quenched rapidly
to obtain TFE and other fluorocarbons. The mixing of the particles with the plasma gas is very
important in order to achieve a high C:F-ratio in the gas phase, which promotes the desired
reactions. The gas enthalpy in the reactor is a governing factor in the TFE yields that are
obtained.
In this study research was done on particle mixing and the enthalpy distribution in the laboratory
scale reactor. An enthalpy probe was used as the main diagnostic tool. Results indicated that
particle mixing is quite uniform throughout the reactor. A basic one-dimensional mechanistic
model of the reactor was also expanded to assist in· the scale-up of the process. In its present
form the model is adequate for predicting trends in the reactor. The model could still be
expanded further to include reaction kinetics and internal heat transfer in the particles.
Considering the restrictions of the model, satisfactory agreement was obtained between the
model and experimental results. / AFRIKAANSE OPSOMMING: 'n Proses vir die plasmagebaseerde produksie van tetrafluoroetileen (TFE) is deur die Atoomenergiekorporasie
van Suid-Afrika (AEK) ontwikkel. Koolstofpartikels word in 'n gelykstroomCF4-
plasma gevoer en die resulterende plasmagas word vinnig geblus ten einde TFE en ander
fluoor-koolstofverbindings as produkte te verkry. Goeie vermenging van die koolstofpartikels
met die plasmagas is van uiterste belang ten einde 'n hoe C:F-verhouding, wat die gewenste
reaksies bevorder, in die gasfase te verkry. Die entalpie van die plasmagas in die reaktor is 'n
bepalende faktor in die opbrengs TFE wat verkry word.
Vir die doel van hierdie werkstuk is navorsing op laboratoriumskaal gedoen oor partikelvermenging
en die entalpie-verspreiding in die reaktor. Die hoof diagnostiese apparaat wat vir
die doel aangewend is, is die entalpiesonde. Resultate toon dat partikelvermenging naastenby
uniform deur die reaktor voorkom. Verder is 'n basiese een-dimensionele meganistiese model
van die reaktor uitgebrei ten einde van nut te wees in die opskaling van die proses. In sy huidige
vorm is die model voldoende om algemene neigings in die reaktor te voorspel. Die model kan
nog verder uitgebrei word om reaksie-kinetika en interne hitte-oordrag in die partikels in te sluit.
Die beperkings van die model in ag genome, is ooreenstemming tussen die model en eksperimentele
resultate egter bevredigend.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/51440 |
| Date | 06 1900 |
| Creators | Nell, Annalien |
| Contributors | Aldrich, C., Crouse, P. L., Stellenbosch University. Faculty of Engineering. Dept. of Process engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 97, [49] leaves : ill. |
| Rights | Stellenbosch University |
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