The addressed topic is to investigate the power distribution at a base metal refinery and to
identify the potential improvement in power consumption efficiency. The work included in this
study revealed that the power consumption efficiency at the evaluated base metal refinery can be improved.
The significance of this study relates to Eskom’s tariff increases and directive to mining and
large industrial companies to reduce their power consumption as well as the recent incremental
increase in power tariffs. Base metal refineries are substantial power consumers and will be
required to evaluate the efficiency of their base metal production.
A load study was conducted at a base metal refinery in order to determine the current power
consumption at the various process areas. The measurements obtained from the load study
formed the basis for calculations to determine the potential efficiency improvement. The load
study revealed that the electro-winning area contributes to the majority of the power consumed
(52% of total apparent power) at the refinery. The potential improvement in efficiency at the
electro-winning process area was identified by means of evaluating the rectifier and rectifier
transformer power consumption. Methods and technologies for the reduction in power consumption was consequently evaluated and quantified. The potential reduction in conductor losses by converting from global power factor correction to
localised power factor correction for the major plant areas was furthermore identified as an area
of potential efficiency improvement and consequently evaluated.
The improvement in motor efficiency across the base metal refinery was identified by means of
comparing the efficiency and power factor of high efficiency motors to that of the standard
efficiency motors installed at the refinery.
The work included in this study reveals that an improvement in power consumption efficiency
is achievable at the evaluated base metal refinery. An efficiency improvement of 1.785% (real
power reduction of 2.07%) can be achieved by implementing localised power factor correction
and high efficiency motors. An average efficiency improvement of 1.282% (total real power
reduction of 2.78%) can be achieved with the additional implementation of specialised, high efficiency rectifier transformer designs.
The implementation of localised power factor correction as well as high efficiency motors was
identified as short term efficiency improvement projects. A financial study was conducted in
order to determine the cost and payback period associated with the reduction in real power
consumption for implementation of the recommended efficiency improvement projects. The
payback period, required to achieve an average efficiency improvement of 1.785%, was
calculated to be approximately 4 years. The initial capital investment required to implement the
efficiency improvement projects is about R22.5 million. The monthly electricity utility bill
savings associated with the efficiency improvement projects is approximately R455,000. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/9869 |
| Date | 01 November 2013 |
| Creators | Du Toit, Alzaan. |
| Contributors | Ijumba, Nelson M., Boake, I. G. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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