| 1. |
- Khwaja, Salik, et al.
(författare)
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Entrained flow gasification of torrefied lignocellulosic biomass
- 2016
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Ingår i: Papers of the 24TH European Biomass Conference. - Amsterdam : ETA Florence Renewable Energies. ; , s. 1138-1142, s. 1138-1142
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Konferensbidrag (refereegranskat)abstract
- An extensive evaluation program was carried out within the European SECTOR project to evaluate the feasibility of torrefied and densified biomass in available entrained flow gasifiers. Different entrained flow reactors (both atmospheric and pressurized) in different scales, from lab scale to a 240 MW industrial gasifier were used for evaluation of torrefied materials as feedstock. Total behaviours of the new fuel throughout the whole supply chains and the EFG systems were evaluated and documented, including process behaviours in terms of operation, gas quality, products of incomplete gasification, etc. Results showed a significant improvement in fuel properties in terms of storage, logistics, milling and feeding behaviour by torrefaction and densification. Entrained flow gasification of the torrefied biomass was also shown to be feasible without any major showstoppers, even improving the gasification processes. Production of tars and other products of incomplete gasification were often found significantly reduced during gasification of torrefied material.
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| 2. |
- Åberg, Katarina, et al.
(författare)
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Pilot scale experimental validation of the Bio2fuels low-temperature slow pyrolysis system concept
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The “Bio2Fuels” concept previously suggested may potentially achieve a transport driven carbon negativity by use of a combination of; low-temperature slow pyrolysis/high-temperature torrefaction; gas reforming; fuel synthesis; coal replacement by the solid bio-coal stream; and CCS of the resulting flue gases. The initial pre-treatment process suggested may potentially exhibit several advantages and may well facilitate an appealing and cost-efficient conversion system. The present work was comprised of pilot-scale pyrolysis experiments on softwood pellets using a continuous auger screw torrefaction/pyrolysis reactor for validation of the process in the temperature range of 300-425°C. All products were analyzed for composition and the pyrolysis gas (permanent gases + bio-oil) was sampled for particulate matter, permanent gas and bio-oil composition. The volatilization propensity of ash-forming elements was analyzed based on alkali deposits on impactor plates with SEM analysis and ICP-AES analysis of the bio-oil. The volatilization of sulfur and chlorine was also evaluated via char retainment. In addition, an initial test run of thermal pyrolysis gas reforming was performed by operating the thermal oxidation burner in gasification/reforming mode. The results showed that the hydrogen and oxygen in the biomass feedstock were volatilized at lower temperatures than the feedstock carbon, with the desired resulting hydrogen/carbon separation into pyrolysis gas and biochar, but also enrichment of oxygen in the pyrolysis gas. The hydrogen pyrolysis gas yield was >75% for pyrolysis temperatures ≥375°C and the corresponding carbon gas yield ranged from 50% to 63%. Most of the hydrogen in the pyrolysis gas was bound in the bio-oil as water and various hydrocarbons. No significant volatilization of alkali elements was observed through either analysis method. The most abundant permanent gas formed was CO2 and with a CH4 concentration of about 9%vol. The thermal reforming experiments also demonstrated a high CH4 syngas concentration, strongly indicating the need for a catalytic reforming process.
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