The use of alternative fuels, also called as co-processing, has the simultaneous recycling of materials as well as the recovery of energy from waste by way of a thermal process. This option replaces natural mineral resources and also fossil fuels, like coal, along with petroleum products. Waste fuels are efficiently made use of within a cement kiln by harnessing the heat value, which helps in the substitution of fossil fuels as well as the incorporation of the resulting ash as a choice for raw materials. Due to this, there isn’t any waste residue that is left behind in the process.
The usage of secondary materials in cement kilns happens to be critical for society to lessen its CO2 emissions while also supporting the vision of a carbon-neutral Europe by 2050. It not only offers sound as well as sustainable solutions for waste streams but, at the same time, strengthens the circular economy.
Besides, the cement sector happens to play a very crucial role in offering a secure as well as cost-effective method for national authorities, along with other industries, to dispose of waste. This is achieved by way of co-processing, which involves converting waste as well as by-products into valuable resources that can be used in the production of cement. It is indeed important to note that air emissions would not dip if cement kilns exclusively used fossil fuels because emissions are mainly affected due to the natural raw materials used, which make up almost 85% of the total material input. In contrast, fuels only contribute 15% of the total material input. It is well to be noted that air emissions can vary irrespective of the type of fuel that happens to be used.
Both biomass as well as non-biomass waste fuels are obtained by way of intermediary waste treatment processes, which go on to involve the collection and processing of various waste streams to produce the final fuel. The fuel gets produced in line with the specifications that are set by the authorities for its use in the cement kilns.
Making utmost use of the capacity of waste-to-energy happens to have the benefit of minimizing the requirement for additional investments in new waste-to-energy infrastructure. In addition, EU member states have what it takes to save almost €12.2 billion by utilizing the current capacity within the EU cement industry. The amount of money saved happens to be equal to the amount of money which is required to build new waste-to-energy incinerators. Co-processing happens to be a more efficient solution for waste management compared to landfilling or even incineration. This demonstrates that the cement industry goes on to play a crucial role in the circular economy as it actively makes use of waste materials.
The clinker process happens to be known for its high energy efficiency. A significant amount of waste heat is recovered by way of the procedure of drying the raw materials as well as fuels in incorporated grinding mills. The cement industry has achieved great success when it comes to reducing costs and carbon footprints by focusing on high energy efficiency, utilizing alternative fuels, along with incorporating renewable energy sources. The European Cement Research Academy’s technical report, named- Evaluation of the energy performance of cement kilns in the context of co-processing, states that the energy efficiency of cement kilns can range between 70% and 80%, depending on the moisture content found in the raw materials.
Alternative fuels in the cement industry: Overview and Achievements
The European cement industry started making use of alternative fuels- AF as a resource more than 30 years ago, especially in 1990. Since then, the usage rate when it comes to AF has been consistently increasing each year, with an average rate of 53% in the EU-27 in 2021. At present, there are several cement plants that are functioning at a very high rate, ranging from 90% to 100% of the AF substation. Moreover, the trend indicates that more cement plants are going to be able to achieve this level in the future. The EU cement industry commonly makes use of various alternative fuels like solid recovered fuel- SRF/refused derived fuel- RDF, end-of-life tyres, animal meal, sewage sludge, wood, paper, and pulp waste, sawdust, as well as others.
It is well to be noted that the average AF rate of 53% in the EU-27 goes on to include 20% of biomass waste. This is especially significant because biomass waste is considered carbon neutral within the EU-Emissions Trading Scheme, which means that its CO2 emissions are calculated as neutral. The biomass waste used within the cement industry happens to come from various sources, which include the biomass fraction found in refuse-derived fuels- RDF, end-of-life tires, sawdust from related industries or processing, animal meals, agricultural as well as wood waste. In 2021, the EU cement industry successfully went on to avoid almost 23 million t of CO2 emissions by making use of alternative fuels. This impressive achievement is equivalent to the amount of CO2 emissions generated by 15 million cars. The EU cement industry utilized around 36 million tons of secondary materials, such as waste and by-products, in the overall process of manufacturing cement. Almost 13 million metric tons were specifically utilized as fuel alternatives within the clinker production process.
