Biogenic carbon-enriched and pollutant depleted SRF from commercial and pretreated heterogeneous waste generated by NIR sensor-based sorting

Abstract

Mechanical processing using predominantly particle size and density as separation criteria is currently applied in the production of solid-recovered fuel or refuse-derived fuel. It does not sufficiently allow for the optimization of the quality of heterogeneous solid waste for subsequent energy recovery. Material-specific processing, in contrast, allows the separation criterion to be linked to specific chemical constituents. Therefore, the technical applicability of material-specific sorting of heterogeneous waste, in order to optimize its routing options, was evaluated. Two sorting steps were tested on a pilot and a large scale. Near infrared multiplexed sensor-based sorting devices were used (1) to reduce the chlorine (Cl) respectively pollutant content, in order to broaden the utilization options of SRF in industrial co-incineration, and (2) to increase the biogenic carbon (C(bio)) content, which is highly relevant in the light of the EU emission trading scheme on CO₂. It was found that the technology is generally applicable for the heterogeneous waste fractions looked at, if the sensor systems are appropriately adjusted for the sorting task. The first sorting step allowed for the removal of up to 40% of the Cl freight by separating only 3 to 5% of the material mass. Very low Cl concentrations were achieved in the output stream to be used as solid-recovered fuel stream and additionally, the cadmium (Cd) and lead (Pb) concentration was decreased. A two- to four-fold enriched C(bio) content was achieved by the second sorting step. Due to lower yields in the large-scale test further challenges need to be addressed.

Production and Characterisation of SRF Premium Quality From Municipal and Commercial Solid Non-Hazardous Wastes in Austria, Croatia, Slovenia and Slovakia

“…The chlorine content in the finished SRF is in most cases still below 1% DM , that is required by cement industry on international market. The installation of modern NIR-sorting technology for sorting out PVC can be advisable for Type #3 production plants when the critical limit may be exceeded and Cl:Sratio must be decreased (Kreindl, 2010;Pieber et al, 2012).…”

Solid recovered fuels in the cement industry with special respect to hazardous waste

“…Latest investigations show that NIR sensor-based sorting can strongly increase the biogenic carbon content of SRF, so that the biogenic CO 2 -emissions may reach quite high percentages (Pieber et al, 2012).…”

Design and quality assurance for solid recovered fuel

“…In the meantime, emission trading (Directive 2003/87 EC (EC, 2003)) has opened a new scope for use of SRF, because due to its relative high biomass content (between 30 and 55%, depending on the calorific value), emission certificates can be saved by co-incineration plants when using SRF. Even higher biogenic portions may be achieved for specific commercial and industrial waste and SRF specifically processed in order to gain higher biogenic portions (Pieber et al, 2011, 2012). There is also a great opportunity for SRF in developing countries where, in the past, huge amounts of high calorific waste fractions are deposited in landfills or at dumping sites (Dorn et al, 2012).…”