9 May 2013 – Anglo Platinum has initiated a US$12 million independent power producer (IPP) project to help recover waste heat energy from its platinum converting process at its Waterval smelter complex in Rustenburg. This project will harvest some 20 MW of thermal energy and return about 3.75 MW of electrical energy into the grid. The total cost of energy saved is estimated to be worth US$1.5 million.
The platinum producer says that the introduction of private sector power generation has multiple benefits, including job creation, reducing the financial burden on the state and improving supply and pricing. Funding for the project was obtained from Investec bank the South African department of trade and industry provided development finance.
As a result of this project the potential saving on carbon emissions is about 19,000 tonnes of CO2 a year, which based on current carbon tax proposals in South Africa could save US$3 million.
The project focuses on extracting waste heat given off during the platinum converter cooling process. In the past this process was undertaken using air-based fans. The new process will use a high pressure water system in which the extraction of waste heat is achieved by implementing an organic rankine cycle technology.
This technology is based on a closed system of fluid that allows heat recovery from lower temperature from lower temperature sources such as industrial waste heat. The low temperature heat is converted into electrical energy that feeds into a grid system.
The high pressure water exchanges heat with an organic medium converted to a vapour. The organic vapour is used to drive a turbine, converting heat energy to electrical energy. The cooler high-pressure water is returned to the converter and the organic vapour is condensed in the closed circuit and reused.
The 15 year agreement signed by Anglo Platinum with the IPP is an example of how alternate funding models can be used effectively in the mining sector.