Recent Developments on the Operation of Cement Kilns - Alternative Fuels and Technology

摘要

Reduced fuel costs and potential CO_2 savings have been driving forces for implementation of so-called alternative fuels in cement production. Alternative fuels are non-fossil fuels derived from biomass or waste. In addition, the modern cement production process is well suited for alternative fuels utilization, as the ash components are recycled into the final cement clinker product, and that the process conditions with high temperatures and high residence times provide good conditions for oxidation of unwanted intermediate products from the combustion process. In order to effectively use alternative fuels and cement production, burning technology design has progressed simultaneously. In the calciner part of the process, where normally 60% of the thermal energy is fired, there has been a trend that reactors are designed with higher gas residence times and other features to enhance combustion of difficult fuels. For application of very difficult alternative fuels in the calciner, extra combustion equipment, such as the HOTDISC, can be installed to improve production performance. In the rotary kiln of the cement production process, where the remaining 40% of the fuel typically is fired, burners often are designed with additional fuel pipes to accommodate wishes for different fuel mixtures.