This pilot study aimed to develop a production line for SRF production from RDF by extracting prohibited materials, grinding, and drying, and the energy potential for using SRF in the cement industry as an alternative fuel was evaluated. This paper defined the main characteristics of RDF, which were obtained after the separation of the biological fraction from MSW at an MBT plant. According to its characteristics, RDF can only be used for incineration in the CPP to obtain heat and energy. The produced SRF meets the requirements for fuel from waste and can be used as an alternative fuel for clinker firing. A technological process line for SRF production from RDF has been developed by adding technical units to the existing MBT line. The SRF production line yield was calculated as 4.47 t/h. At the end of the SRF production process, the moisture content of the finished product decreased by 85%, and the volume decreased by 18%. The obtained SRF had a high calorific value, low moisture content, and a permissible value of chlorine and mercury. It was proposed that the produced SRF and sewage sludge (already used during the clinker firing process) be utilized as alternative fuels since they correspond to the oxide composition of the finished clinker in elemental and oxide composition. A calculation to assess the economic and environmental efficiency of the use of SRF in the cement kiln was conducted. The result showed that using 10% SRF as a substitute fuel for coal used in clinker roasting at 1.92 t/h would save 601.7 USD/h coal costs. This use of SRF will emit 3.7 t/h CO2 and achieve net savings of 754.7 USD/h.

Production, quality and quality assurance, as well as co-incineration of solid recovered fuels in cement industry, have become state-of-the-art in the European cement industry. At the global level, average thermal substitution rate is about 17%, whereby, only 13% in Canada and in the USA 16%, while in the European Union 28 it is about 44% (i.e. 11,300,000 t waste fuels utilised in 2016). In Austria, thermal substitution rate was ca. 80% in 2017, which was worldwide the highest one. Regarding solid recovered fuels for the cement industry, two types are relevant, namely solid recovered fuels PREMIUM Quality and solid recovered fuels MEDIUM Quality. In the case study shown, solid recovered fuels PREMIUM Quality from 11 and solid recovered fuels MEDIUM Quality from nine different solid recovered fuels production plants have been investigated. Investigations consist of sorting and sieving analyses (for PREMIUM), as well as physical-chemical analyses (for both solid recovered fuels types) according to the (inter)national standards (i.e. Austrian \'ÖNORM\', European \'EN\' standards and CEN TC 343 guidelines). The results gained from the first investigation were published in 2014 and here, results of further investigations are updated for 2016 and 2018 and confronted with legal and market relevant requirements. During the investigation, not enough parallel samples could be investigated and therefore no adequate scientific statistical analyses could be elaborated but a more practical indicative interpretation has been made. Finally, it can be confirmed, that all investigated solid recovered fuels fulfil the Austrian legal and international solid recovered fuels and co-incineration market requirements.

This paper describes the requirements for the production, quality, and quality assurance of solid recovered fuels (SRF) that are increasingly used in the cement industry. Different aspects have to be considered before using SRF as an alternative fuel. Here, a study on the quality of SRF used in the cement industry is presented. This overview is completed by an investigation of type and properties of input materials used at waste splitting and SRF production plants in Austria. As a simplified classification, SRF can be divided into two classes: a fine, high-calorific SRF for the main burner, or coarser SRF material with low calorific value for secondary firing systems, such as precombustion chambers or similar systems. In the present study, SRFs coming from various sources that fall under these two different waste fuel classes are discussed. Both SRFs are actually fired in the grey clinker kiln of the Holcim (Slovensko) plant in Rohožnik (Slovakia). The fine premium-quality material is used in the main burner and the coarse regular-quality material is fed to a FLS Hotdisc combustion device. In general, the alternative fuels are used instead of their substituted fossil fuels. For this, chemical compositions and other properties of SRF were compared to hard coal as one of the most common conventional fuels in Europe. This approach allows to compare the heavy metal input from traditional and alternative fuels and to comment on the legal requirements on SRF that, at the moment, are under development in Europe.