A laboratory scale delayed coking process was used to produce petrol precursors, diesel
precursors, methane rich gas, green and calcined coke from five previously untested South
African heavy petroleum residues.
The ash content of the heavy petroleum residues was found to be detrimental to the
microstructure of the green coke and Coefficient of Thermal Expansion (CTE) of the
calcined coke. The sulphur content of the calcined cokes produced was found to be in-line
with typical global anode grade cokes. De-ashing of the feedstock would be necessary to
produce anode grade fillers for the aluminium industry. The local production of anode grade
coke would serve to reduce imports and supply the aluminium smelters on the east coast of
South Africa.
The heavy petroleum residues (also known as heavy fuel oil) are currently used as bunker
fuel in the shipping industry and are responsible for substantial air pollution. Delayed coking
of these residues could extend the production of petrol and diesel per barrel of imported
crude oil and reduce the effect on South Africa’s balance of payments deficit and impact the
environment in a beneficial manner with respect to carbon dioxide and sulphur emissions.
The research also evaluated the replacement of heavy fuel oil with marine diesel produced by
delayed coking of the former. Marine diesel was found to emit less sulphur oxides and have a
higher energy density per unit of carbon dioxide emitted. While seawater scrubbing of the
heavy fuel oil would be more cost effective in reducing the sulphur oxide emissions, it would
not contribute to carbon dioxide reductions. The research created a hypothetical scenario to
determine the required value of Clean Development Mechanism credits for a marine diesel
replacement, were shipping to be incorporated under the Kyoto Protocol in future
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/6831 |
| Date | 27 March 2009 |
| Creators | Clark, John Graham |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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