Design, quality and quality assurance of solid recovered fuels for the substitution of fossil feedstock in the cement industry – Update 2019

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.

Utilization of alternative fuels and materials in cement kiln towards emissions of benzene, toluene, ethyl-benzene and xylenes (BTEX)

Co-processing in cement industry has benefits for energy conservation and waste recycling. Nevertheless, emissions of benzene, toluene, ethyl-benzene, and xylenes (BTEX) tend to increase compared to a non co-processing kiln. A study was conducted in kiln feeding solid AFR (similar to municipal solid waste, MSW) having production capacity 4600-ton clinker/day (max. 5000 ton/day) and kiln feeding biomass having production capacity 7800-ton clinker/day (max. 8000 ton/day). The concentration of VOCs emissions tends to be higher at the raw mill on rather than the raw mill off. At the raw mill on, concentration of total volatile organic carbon (VOCs) emission from cement kiln stack feeding Solid AFR 1, biomass, Solid AFR 2, and mixture of Solid AFR and biomass is 16.18 mg/Nm3, 16.15 mg/Nm3, 9.02 mg/Nm3, and 14.11 mg/Nm3 respectively. The utilization of biomass resulted in the lower fraction of benzene and the higher fraction of xylenes in the total VOCs emission. Operating conditions such as thermal substitution rate, preheater temperature, and kiln speed are also likely to affect BTEX emissions.

‘Thermal substitution’ for preparing ternary BCN nanosheets with enhanced and controllable nonlinear optical performance

A novel ‘thermal substitution’ method is used to prepare BCN nanosheets and the as-obtained nanosheets show controllable NLO properties.