South Africa is on a path of dramatically increasing its energy supplying capabilties.
Eskom (the main utility supplying electricity to the national grid) recently announced
that future power station technologies will focus on renewable energy and nuclear
power. This is done in an effort to reduce South Africa’s dependance on burning
fossil-fuels and thereby decreasing CO2 emissions and other harmful gases. This,
together with the fact that there are a lot of fresh water scarce areas especially along the
Eastern Cape coast of South Africa, is what inspired this study. This study investigates
the use of a 200 MWth High Temperature Reactor (HTR) for cogeneration purposes.
Heat from the reactor is utilised for electricity generation (Rankine cycle) and process
heat (desalination). Two desalination concepts were evaluated thermodynamically and
economically, namely Multi-Effect Distillation (MED) and Reverse Osmosis (RO).
Computer software, Engineering Equation Solver (EES), was used to simulate different
cycle configurations, where the heat available in the condenser was increased
successively.
The coupling of the two desalination technologies with a HTR was compared and it was
found that a RO plant produces nearly twice as much water while sending the same
amount of electricity to the grid (compared to coupling with MED). Coupling options
were investigated and each simulation model was optimised to deliver maximum output
(power and water).
The best configuration was found to be the coupling of a HTR with a RO plant
producing 86.56 MW generator power. This is equal to 2077 MWh/day. Using
332 MWh/day for desalination through RO, delivers 73 833 m3/day fresh water and
results in 1745 MWh/day sent to the grid. This scenario is the best option from a
thermodynamic and economic point of view. From an investment point of view, it will
produce an Internal Rate of Return (IRR) of 10.9 percent and the Net Present Value
(NPV) is calculated to be R 2,486,958,689.
The results and analysis for the different cycle configurations are presented in such a
way that an easy comparison can be made. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2011
| Identifer | oai:union.ndltd.org:NWUBOLOKA1/oai:dspace.nwu.ac.za:10394/8416 |
| Date | January 2011 |
| Creators | Nel, Ryno |
| Publisher | North-West University |
| Source Sets | North-West University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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