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High temperature air/steam gasification of biomass in an updraft fixed bed batch type gasifier
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
2005 (English)Doctoral thesis, comprehensive summary (Other scientific)
Place, publisher, year, edition, pages
Stockholm: KTH , 2005. , 100 p.
Keyword [en]
Materials science
Keyword [sv]
Materialvetenskap
National Category
Materials Engineering
Identifiers
URN: urn:nbn:se:kth:diva-224ISBN: 91-7178-067-X (print)OAI: oai:DiVA.org:kth-224DiVA: diva2:7957
Public defence
2005-05-30, sal D3, Lindstedtsvägen 5, Stockholm, 10:00
Opponent
Supervisors
Note
QC 20101020Available from: 2005-05-26 Created: 2005-05-26 Last updated: 2010-10-20Bibliographically approved
List of papers
1. High-temperature air and steam gasification of densified biofuels
Open this publication in new window or tab >>High-temperature air and steam gasification of densified biofuels
2004 (English)In: BIOMASS BIOENERG, 2004, Vol. 27, no 6, 563-575 p.Conference paper, Published paper (Refereed)
Abstract [en]

An experimental study was carried out to investigate gasification of densified biofuels using highly preheated air and steam as a gasifying agent. Preheat of air and steam is realised by means of the newly developed high-cycle regenerative air/steam preheater. Use of highly preheated feed gas provides additional energy into the gasification process, which enhances the thermal decomposition of the gasified solids. For the same type of feedstock the operating parameters, temperature, composition and amount of gasifying agent, were varied over a wide range. Results of experiments conducted in. a high-temperature air/steam fixed bed updraft gasifier show the capability of this technology of maximising the gaseous product yield as a result of the high heating rates involved, and the efficient tar reduction. Increase of the feed gas temperature reduces production of tars, soot and char residue as well as increases heating value of the dry fuel gas produced. Overall, it has been seen that the yield and the lower heating value of the dry fuel gas increase with increasing temperature.

Series
Biomass & bioenergy, ISSN 0961-9534
Keyword
high-temperature gasification, fixed bed, updraft, pellets
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-25396 (URN)10.1016/j.biombioe.2003.08.015 (DOI)000224440600007 ()2-s2.0-4344599227 (Scopus ID)
Conference
1st World Conference on Pellets Stockholm, SWEDEN, SEP 09-13, 2002
Note
QC 20101020. Available from: 2010-10-20 Created: 2010-10-20 Last updated: 2011-10-20Bibliographically approved
2. Gasification of biomass wstes in updraft fixed bed gasifier with high temperature air and steam
Open this publication in new window or tab >>Gasification of biomass wstes in updraft fixed bed gasifier with high temperature air and steam
2005 (English)Report (Other academic)
Publisher
6 p.
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-25397 (URN)KTH/MSE--05/42--SE+ENERGY/ART (ISRN)
Note
QC 20101020Available from: 2010-10-20 Created: 2010-10-20 Last updated: 2010-10-20Bibliographically approved
3. High Temperature Air And Steam Gasification Of Wood Pellets
Open this publication in new window or tab >>High Temperature Air And Steam Gasification Of Wood Pellets
2002 (English)Report (Other academic)
Publisher
5 p.
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-25398 (URN)KTH/MSE--05/45--SE+ENERGY/ART (ISRN)
Conference
Finnish-Swedish flame days 2002. IFRF, Vaasa, 24-25 September, Finland
Note

Presented to: Finnish-Swedish flame days 2002. IFRF, Vaasa, 24-25 September, Finland QC 20101020

Available from: 2010-10-20 Created: 2010-10-20 Last updated: 2012-09-21Bibliographically approved
4. Reforming Of Biomass Wastes Into Fuel Gas With High Temperature Air And Steam
Open this publication in new window or tab >>Reforming Of Biomass Wastes Into Fuel Gas With High Temperature Air And Steam
2005 (English)Report (Other academic)
Abstract [en]

The presented work aims to provide information on solid biomass conversion into fuel gas as a result of air and steam gasification process. In contrary to the conventional gasification in this work highly preheated air and steam is used as a gasifying agent. Preheat of air and steam is realised by means of the high-cycle regenerative air/steam preheater. Use of highly preheated gasifying media provides additional energy into the gasification process that enhances the thermal decomposition of the gasified solids. The objective of this work is to provide information on the process of biomass wastes reforming to fuel gas using high temperature air and steam gasification.High Temperature Air/Steam Gasification of biomass wastes has very clear economical and environmental benefits. It will increase consumption of biomass thus decreases CO2 emissions. Apart from CO2 reduction possibility, the new process, High Temperature Gasification has the following advantages:- Clean fuel gas for production of heat or electricity,- No need to treat ashes from gasification since there is no ash or at least no carbon in the ash produced,- No need to landfill since the produced slag can be used for example as a building material.In this work high temperature air and steam gasification of charcoal and wood pellets in a fixed bed updraft gasifier is tested. The following conclusions were found out:

• For both charcoal and wood pellets gasification cases it was seen that an increase of steam molar fraction in the feed gas decreases the temperature of the gasification, the gasification rate, the mass yield of the fuel and molar fraction of carbon monoxide but increases molar fraction of hydrogen,

• An increase of the feed gas temperature reduces production of tars, soot and char residue as well as increases calorific value of the fuel gas produced,

• Preheating of the feed gas obtains a higher gasification efficiency and a higher gasification rate,

• High temperature air and mixture of air and steam used as feed gas in a fixed bed gasifier shows the capability of this technology of maximising the gaseous product yield,

• High lower heating value of fuel gas and high molar fraction of hydrogen and hydrocarbons obtained by using high temperature air and steam gasification technology increase the technical possibility of the application of fuel gas produced.

Publisher
15 p.
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-25399 (URN)KTH/MSE--05/44--SE+ENERGY/ART (ISRN)
Note

QC 20101020

Available from: 2010-10-20 Created: 2010-10-20 Last updated: 2012-09-21Bibliographically approved
5. Mathematical model of biomass gasification using high temperature air in fixed beds
Open this publication in new window or tab >>Mathematical model of biomass gasification using high temperature air in fixed beds
Show others...
2007 (English)In: Progress in Computational Fluid Dynamics, An International Journal, ISSN 1468-4349, E-ISSN 1741-5233, Vol. 7, no 1, 58-67 p.Article in journal (Refereed) Published
Abstract [en]

A mathematical model has been formulated for predicting the main chemical and physical processes taking place during the fixed-bed gasification of biomass fuels using high temperature air (up to 1000 degrees C). Predicted gas species concentrations profiles and their maximum values are in good agreement with measurements. The results also show that when the temperature of feed gas (air) is increased a higher gasification rate, higher molar fractions of fuel gases (CO, H-2 and CmHn) are obtained, thus resulting in a higher LHV. At a high flow rate of the feed gases, the peaks of the fuel gas concentrations are slightly increased, and the gasification rate is strongly increased. A smaller particle size of the biomass fuels leads to higher peak values of the fuel gas species molar fractions, and a more stable gasification zone for a relatively long period of time.

Keyword
mathematical modelling, gasification, biomass fuel, fixed bed, high temperature air, coal
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-16365 (URN)10.1504/PCFD.2007.011886 (DOI)000243962700008 ()2-s2.0-33847019177 (Scopus ID)
Note
QC 20100525Available from: 2010-08-05 Created: 2010-08-05 Last updated: 2017-12-12Bibliographically approved

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CiteExportLink to record
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Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
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  • de-DE
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  • en-US
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  • Other locale
More languages
Output format
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