Development of SEG process:
Different feedstocks (wood pellets, pine wood, straw, grape seeds, different samples of municipal solid waste from Econward plant) have been characterised and tested in the 30 kW bubbling fluidized bed gasifier at CSIC.
TRL5 validation tests have been carried out in the 200 kW pilot facility at the University of Stuttgart with wood pellets and municipal solid waste derived pellets. Operational flexibility of the SEG process was demonstrated, by showing the capability of controlling the syngas composition by modifying the solids circulation rate. To reach the target syngas M-module (M=(H2-CO2)/(CO+CO2)) of 2, a gasification temperature of approximately 720-740°C is needed. Higher gasification temperatures lead to lower M, allowing mixing of hydrogen from electrolysis.
Development of SEDMES process:
SEDMES process has been tested in different facilities from TRL3 to TRL5, that allowed to test different materials, including catalysts developed by CSIC, and conditions representative of different cycles. During the TRL5 experimental campaign at TNO in a multi-column PSA facility, more than 500 full cycles have been measured. All SEDMES objectives, demonstrated at TRL3 and TRL4, have been confirmed at TRL5. The process has demonstrated a more than halved single passage remaining CO+CO2 content compared to the conventional process. The formation of CO2 can be suppressed, with carbon selectivity to CO2 of less than 5%. Furthermore, SEDMES is highly flexible with respect to the CO/CO2-ratio in the feed, where the conversion of CO2 to DME performs similarly to the conversion of CO.
Process modelling and techno-economic analysis:
The complete FLEDGED process that combines the SEG and the SEDMES processes has been assessed through process simulation study at POLIMI, exploiting SEG models developed by LUT and SEDMES models developed by TNO. The economic analysis has been carried out with the support of the industrial partners FRES, SFW and Econward.
Different FLEDGED cases have been assessed, namely: F1: baseline case; F2: case with CO2 capture and storage (bio-CCS); F3: case with enhanced production thanks to the integration with the electrolyzer. The obtained technical performance are in line with the targets. The baseline FLEDGED case (F1 ) reached overall fuel efficiency of 58.5%, increasing to 65.7% in enhanced operations with hydrogen addition (F3). The economic analysis resuklted in a cost of DME of about 20 €/GJ for the baseline case F1, excluding the biomass cost.
Risk and Sustainability Analysis:
Risk assessment of the different process units of the FLEDGED biomass to DME value chains has been carried out by INERIS. The main risk scenarios were identified, the cause and the consequences were identified followed by the proposition of the risk mitigation measures. A WTW analysis has been performed by QUANTIS. Net WTW CO2 emissions <10 gCO2/km for the baseline FLEDGED case (F1). When in a bio-CCS configuration (case F2), the FLEDGED process can achieve negative emissions estimated equal to -190 gCO2/km. The socio-economic analysis (SEA) of the FLEDGED concept has been carried out by INERIS using monetary estimates of induced environmental and health impacts identified in LCA and modelling air quality and health impacts in EU28 of different DME use scenarios.
Exploitation study:
Commercial exploitation study with business model have been developed by Econward, FRES and Sumitomo FW with reference to: (i) small-scale plant for the conversion of MSW into DME, for subsequent use in garbage diesel trucks and other heavy vehicles and (ii) large-scale plant (100 MWth) for conversion of forestry biomass or lignin into DME.
Combination of conditions needed to make the commercial deployment of FLEDGED processes economically feasible have been identified.
