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Optimisation criteria of a Rankine steam cycle powered by thorium HTR / Steven Cronier van Niekerk

HOLCIM has various cement production plants across India. These plants struggle to
produce the projected amount of cement due to electricity shortages. Although coal is
abundant in India, the production thereof is in short supply.
It is proposed that a thorium HTR (100 MWt) combined with a PCU (Rankine cycle) be
constructed to supply a cement production plant with the required energy. The Portland
cement production process is investigated and it is found that process heat integration is not
feasible.
The problem is that for the feasibility of this IPP to be assessed, a Rankine cycle needs to be
adapted and optimised to suit the limitations and requirements of a 100 MWt thorium HTR.
Advantages of the small thorium HTR (100 MWt) include: on-site construction; a naturally
safe design and low energy production costs. The reactor delivers high temperature helium
(750°C) at a mass flow of 38.55 kg/s. Helium re-en ters the reactor core at 250°C.
Since the location of the cement production plant is unknown, both wet and dry cooling tower
options are investigated. An overall average ambient temperature of India is used as input
for the cooling tower calculations.
EES software is used to construct a simulation model with the capability of optimising the
Rankine cycle for maximum efficiency while accommodating various out of the norm input
parameters. Various limitations are enforced by the simulation model.
Various cycle configurations are optimised (EES) and weighed against each other. The
accuracy of the EES simulation model is verified using FlowNex while the optimised cycle
results are verified using Excel’s X-Steam macro.
It is recommended that a wet cooling tower is implemented if possible. The 85% effective
heat exchanger delivers the techno-economically optimum Rankine cycle configuration. For
this combination of cooling tower and heat exchanger, it is recommended that the cycle
configuration consists of one de-aerator and two closed feed heaters (one specified).
After the Rankine cycle (PCU) has been designed and optimised, it is evident that the small
thorium HTR (100 MWt) can supply the HOLCIM plant with the required energy. The optimum cycle configuration, as recommended, operates with a cycle efficiency of 42.4%
while producing 39.867 MWe. A minimum of 10 MWe can be sold to the Indian distribution
network at all times, thus generating revenue. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:nwu/oai:dspace.nwu.ac.za:10394/12209
Date January 2014
CreatorsVan Niekerk, Steven Cronier
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeThesis

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