Cement manufacturing is particularly energy-intensive. In order to reduce the use of expensive primary fuels like coal and oil, cement plant operators focus increasingly on alternative fuels and raw materials (AFR). The use is generally focused on the fuels. Neither the manufacturing process, the end product, nor the emissions may be affected. Therefore, high-caloric wastes that cannot be further recycled, e.g. from plastic and packaging residues, paper, composite material or textiles, have to be treated beforehand to be ready for incineration.
In order to help customers efficiently convey, store and dose the treated fuels, BEUMER Group has established the new business segment AFR systems.Germany, October 1973: For political reasons, Arab countries reduced their oil production, which caused oil prices to skyrocket. This was a very precarious situation, because crude oil was an important energy source, also for the cement industry to operate their rotary kilns. With this first oil crisis, plant operators started to shift towards using cost-effective fuels and raw materials.
Besides mineral waste that can be used as alternative raw material, the market primarily employs the use of fuel alternatives, because approximately 30 per cent of production costs are spent on energy. In addition to fluid alternative fuels, such as used oil or solvents, the majority of solid fuels consist of complete or shredded scrap tyres, scrap wood, or mixtures of plastic, paper, composite materials or textiles. After they have been treated and quality-controlled, they show calorific values similar to brown coal. The calorific value of scrap tyres is even comparable to that of stone coal. When producing cement, it is also necessary to ensure that the quality of the ash residues matches the quality of the end product. As all material components are completely incorporated into the clinker and mineralised. Their use makes for an economic production process. In addition, primary raw and fuel supplies are conserved and landfill volume is reduced.
Pre-treated secondary fuels are mostly supplied from external vendors, ready for incineration. BEUMER Group now offers tailor-made AFR systems to lime and cement plants for the safe transport and storage of solid materials. Based on wide-ranging experiences and the customer's requirements, the systems comprise the entire chain, from receiving and unloading the delivery vehicle, up to storing, sampling, conveying and dosing solid alternative fuels. BEUMER Group, provider of intralogistics, supplies its customers worldwide now with three systems, from one single source.
Tailored to every application
BEUMER Group's program includes the starter system that is used at the main burner. In the cement and limestone industry, primary fuels are usually ground to grain sizes of less than 100 micrometres and fed via the burner. At the end of the rotary kiln, the burner heats up to 2000°C, the temperature that is needed for limestone, sand, clay and ore to react and become clinker as an intermediate product. In order to use solid secondary fuels in the clinkering zone burner, they should deliver a calorific value that is at least similar to brown coal (ca. 22 ± 2 MJ/kg), have grain sizes of less than 30 millimetres and burn out while being fed.
The oven-ready material is usually delivered in moving-floor trailers. BEUMER Group provides a docking station that also serves as storage on site. Once the trailer is emptied, it is completely replaced or refilled in the large tent using a wheel loader. The material is metered volumetrically and conveyed to the clinkering zone burner. This solution is deliberately designed as a test system. This way, the operator can test their suppliers, the quality of the fuels and their furnace behaviour.
Adapted from press release by Joseph Green
Read the article online at: https://www.worldcement.com/special-reports/15012016/reliable-energy-supplier-part-1/