ECN publication
Converting Low-value Feedstock Into Energy: Recent Developments in Gasifying Paper Rejects, RDF and MBM at 5 KWTH, 25 KWTH and 80 MWTH Scale
Grootjes, A.J.; Aranda Almansa, G.; Meijden, C.M. van der; Willeboer, W.; Spanjers, M.; Kant, H.F. de; Spit, R.
Published by: Publication date:
ECN Biomass & Energy Efficiency 5-7-2016
ECN report number: Document type:
ECN-M--16-054 Conference Paper
Number of pages: Full text:
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The aim of decreasing the production cost of renewable electricity is expected to reduce the governmental subsidies for (clean, relatively expensive) biomass supply in the future. This makes necessary to find alternative (cheaper, yet troublesome) low-value feedstock. The main technical challenges associated to these fuels are fouling, deposition and corrosion in the gas cooling sections of the plant. The adaptation and optimization of indirect co-firing technology for low-value, difficult feedstock can reduce costs, thus widening the application market. In this work, several low-value, troublesome feedstock (paper rejects, refuse-derived fuel RDF, and meat and bone meal MBM) have been tested both at laboratory scale (5 kWth BFB and 25 kWth MILENA facilities at ECN) and commercial scale (80 MWth CFB gasifier at the Essent’s Amer 9 power plant). The tests have given insight on the required adaptation of the gasifier, the gas cleaning section and the boiler when operating with these specific feedstock. Focus has been placed on the fate and distribution of troublesome compounds (alkalis, chlorine, sulfur, heavy metals). The lab-scale results have shown that a decrease in gasification temperature from 850°C to 750°C leads to a trade-off between fuel conversion and release of contaminants to the gas phase. Furthermore, a different quantitative distribution of fouling elements in the solid- and gas phase has been observed. On the other hand, the concentration of Cl and NH4+ in producer gas is similar from either MILENA indirect gasification or direct BFB gasification. Lastly, results of wood/RDF co-gasification at the 80 MWth CFB gasifier have shown that the gas cooler fouling, the main concern issue, can be reduced by decreasing the gasification temperature, thus leading to higher plant availability.

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