Abstract
Biomass is heading for a great future as renewable energy source. Not only electricity and heat can be produced, also gaseous and liquid fuels may be synthesized from biomass. The present work focuses on entrained flow gasification, which is commercially available on large scale (mainly for coal and liquid fuels) and also can reach the highest efficiency from biomass to so-called biosyngas. As feeding and ash behaviour are expected to be the major hurdles, these issues have been subject of the present study. Two types of entrained flow gasifiers can be distinguished: slagging and non-slagging. It has been concluded that biomass should be converted in a slagging gasifier. Slagging gasification of biomass requires fluxing material in order to obtain the proper slag properties at reasonable temperatures. Silica or clay seems to be the obvious choice. Furthermore, slag recycling might be needed to obtain enough wall coverage. As far as feeding is concerned, there are various options to get biomass into an entrained flow gasifier. Milling wood to 100 mm particles similarly to coal would consume very much electricity (approx. 0.08 kW{sub e}/kW{sub thwood}), which makes this option unattractive. It has been shown however, that torrefaction (a mild thermal treatment) can
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Van der Drift, A;
Boerrigter, H;
Coda, B;
Cieplik, M K;
Hemmes, K
[1]
- ECN Biomass, Petten (Netherlands)
Citation Formats
Van der Drift, A, Boerrigter, H, Coda, B, Cieplik, M K, and Hemmes, K.
Entrained flow gasification of biomass. Ash behaviour, feeding issues, system analyses.
Netherlands: N. p.,
2004.
Web.
Van der Drift, A, Boerrigter, H, Coda, B, Cieplik, M K, & Hemmes, K.
Entrained flow gasification of biomass. Ash behaviour, feeding issues, system analyses.
Netherlands.
Van der Drift, A, Boerrigter, H, Coda, B, Cieplik, M K, and Hemmes, K.
2004.
"Entrained flow gasification of biomass. Ash behaviour, feeding issues, system analyses."
Netherlands.
@misc{etde_20479502,
title = {Entrained flow gasification of biomass. Ash behaviour, feeding issues, system analyses}
author = {Van der Drift, A, Boerrigter, H, Coda, B, Cieplik, M K, and Hemmes, K}
abstractNote = {Biomass is heading for a great future as renewable energy source. Not only electricity and heat can be produced, also gaseous and liquid fuels may be synthesized from biomass. The present work focuses on entrained flow gasification, which is commercially available on large scale (mainly for coal and liquid fuels) and also can reach the highest efficiency from biomass to so-called biosyngas. As feeding and ash behaviour are expected to be the major hurdles, these issues have been subject of the present study. Two types of entrained flow gasifiers can be distinguished: slagging and non-slagging. It has been concluded that biomass should be converted in a slagging gasifier. Slagging gasification of biomass requires fluxing material in order to obtain the proper slag properties at reasonable temperatures. Silica or clay seems to be the obvious choice. Furthermore, slag recycling might be needed to obtain enough wall coverage. As far as feeding is concerned, there are various options to get biomass into an entrained flow gasifier. Milling wood to 100 mm particles similarly to coal would consume very much electricity (approx. 0.08 kW{sub e}/kW{sub thwood}), which makes this option unattractive. It has been shown however, that torrefaction (a mild thermal treatment) can reduce the energy demands upon milling to only 0.01-0.02 kW{sub e}/kW{sub thwood}. It may however be possible to take advantage of the relatively high reactivity of biomass compared to coal. It has been made plausible that biomass particles as large as 1 mm would suffice. This not only means a low electricity consumption upon milling, it also means that screw feeding is possible, which is very attractive compared to pneumatic feeding. This means less electric energy consumption for compression of inert gas, only little syngas dilution by inert gas and resulting into a higher efficiency. Furthermore, if piston feeder systems are used to pressurize the biomass fuel, advantages become even more pronounced. On the basis of efficiency and the above-mentioned facts and opinions, one option is selected as the best choice for the production of syngas from biomass at large-scale. In this system, biomass is milled to 1 mm particles, compressed by piston feeder and subsequently fed by screw into the gasifier. This option has the lowest amount of unit operations and has the highest efficiency. It has been calculated that the efficiency from wood with 35% moisture to 40 bar syngas with H2/CO=2 is 81% (LHV). If net electricity production is included (calculated to primary energy with 40% efficiency), the overall efficiency is 84%. As alternatives, two options are selected where biomass is pre-treated: torrefaction or fast pyrolysis to produce torrefied wood or oil/char-slurry respectively. These systems show lower efficiency (overall efficiency is approximately 75%), higher investment and more complexity compared to the '1 mm' option, but pressurizing and feeding becomes conventional. The next steps towards large-scale biosyngas plants by entrained flow gasification should focus on suitability of 1 mm particles, applicability of screw feeders and piston feeders, soot formation, gas cooling and ash properties. Economic evaluations should be done. A phased approach towards a large-scale plant is proposed consisting of lab-scale, pilot-scale and cofiring experiments.}
place = {Netherlands}
year = {2004}
month = {Apr}
}
title = {Entrained flow gasification of biomass. Ash behaviour, feeding issues, system analyses}
author = {Van der Drift, A, Boerrigter, H, Coda, B, Cieplik, M K, and Hemmes, K}
abstractNote = {Biomass is heading for a great future as renewable energy source. Not only electricity and heat can be produced, also gaseous and liquid fuels may be synthesized from biomass. The present work focuses on entrained flow gasification, which is commercially available on large scale (mainly for coal and liquid fuels) and also can reach the highest efficiency from biomass to so-called biosyngas. As feeding and ash behaviour are expected to be the major hurdles, these issues have been subject of the present study. Two types of entrained flow gasifiers can be distinguished: slagging and non-slagging. It has been concluded that biomass should be converted in a slagging gasifier. Slagging gasification of biomass requires fluxing material in order to obtain the proper slag properties at reasonable temperatures. Silica or clay seems to be the obvious choice. Furthermore, slag recycling might be needed to obtain enough wall coverage. As far as feeding is concerned, there are various options to get biomass into an entrained flow gasifier. Milling wood to 100 mm particles similarly to coal would consume very much electricity (approx. 0.08 kW{sub e}/kW{sub thwood}), which makes this option unattractive. It has been shown however, that torrefaction (a mild thermal treatment) can reduce the energy demands upon milling to only 0.01-0.02 kW{sub e}/kW{sub thwood}. It may however be possible to take advantage of the relatively high reactivity of biomass compared to coal. It has been made plausible that biomass particles as large as 1 mm would suffice. This not only means a low electricity consumption upon milling, it also means that screw feeding is possible, which is very attractive compared to pneumatic feeding. This means less electric energy consumption for compression of inert gas, only little syngas dilution by inert gas and resulting into a higher efficiency. Furthermore, if piston feeder systems are used to pressurize the biomass fuel, advantages become even more pronounced. On the basis of efficiency and the above-mentioned facts and opinions, one option is selected as the best choice for the production of syngas from biomass at large-scale. In this system, biomass is milled to 1 mm particles, compressed by piston feeder and subsequently fed by screw into the gasifier. This option has the lowest amount of unit operations and has the highest efficiency. It has been calculated that the efficiency from wood with 35% moisture to 40 bar syngas with H2/CO=2 is 81% (LHV). If net electricity production is included (calculated to primary energy with 40% efficiency), the overall efficiency is 84%. As alternatives, two options are selected where biomass is pre-treated: torrefaction or fast pyrolysis to produce torrefied wood or oil/char-slurry respectively. These systems show lower efficiency (overall efficiency is approximately 75%), higher investment and more complexity compared to the '1 mm' option, but pressurizing and feeding becomes conventional. The next steps towards large-scale biosyngas plants by entrained flow gasification should focus on suitability of 1 mm particles, applicability of screw feeders and piston feeders, soot formation, gas cooling and ash properties. Economic evaluations should be done. A phased approach towards a large-scale plant is proposed consisting of lab-scale, pilot-scale and cofiring experiments.}
place = {Netherlands}
year = {2004}
month = {Apr}
}