Energy analysis and environmental impact assessment of a cement plant

Energy, exergy and cost-benefit analyses were conducted on a cement plant in South Africa in order to identify the best energy improvement options. It was found that an energy saving project is more likely to be attractive in Europe than in South Africa. This can be attributed to low fuel prices and high interest rates (long pay-back times) in South Africa. The utilisable exergetic efficiency was used to quantify the effect of proposed energy saving measures. The most promising option for saving energy and improving the exergetic efficiency proved to be insulation of the preheater system. A payback time of only 7.5 months was calculated for this option and the utilisable exergetic efficiency increased from 39% to 43%. The benefits obtained from increasing exergetic efficiency is not only financial, but can also be translated into a decrease in environmental impact in the case of cement production. This was shown using the Eco Indicator’95 method for quantifying environmental impact.