Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Investigation of thermal biomass gasification for sustainable small scale rural electricity generation in Uganda
KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
2011 (English)Licentiate thesis, monograph (Other academic)
Abstract [en]

With the increasing need for renewable energy technologies in the world, biomass fuel transformation technology is growing towards meeting that need, among others. Challenges remain certain and new innovations are being tested in bid to overcome them with the application of biomass as energy source. This report presents some studies carried out into understanding the potential and challenges associated with utilization of biomass fuel, especially for technologies that are appropriate for rural applications.  Utilization of biomass gasification technologies is in the focus of this study.

 

The great potential biomass fuel provide to Uganda for possible energy production in small scale application is presented. This study was carried out to understand the possibility of using biomass as fuel in electricity power generation in Uganda. It takes into consideration the use of biomass gasification technology in energy production. Challenges related to the application of biomass fuels are discussed, mostly with tar and alkali metal compounds in the gas stream.

 

Suggested methods to combat some of the challenges with biomass fuels are pointed out in this study. Application of externally fired gas turbine (EFGT) system is a particular approach discussed and its technical performance analyzed.  The analysis revealed that efficiency of the EFGT system is greatly dependent on the heat exchanger effectiveness and on turbine inlet temperature. Optimum performance can be realized with air compression ratio of 3.4. It is also noted that fouling and deposition in the heat exchanger can affect its performance.

 

A related study carried out was on the retention of alkali metals in an updraft gasifier. The gasifier was chosen for possible integration with the EFGT system. Finding was that about 99% of the alkali metals are retained in the gasifier. It is anticipated that this would reduce on the deposition in the heat exchanger, reducing on maintenance time. A need is identified to determine the level of deposition mentioned. A simple thermodynamic modeling of the alkali metals condensation reaction on a high temperature heat exchanger surface was conducted. The results showed that with appropriate quantity of S in the raw fuel, alkali metals bounding with Cl are greatly reduced. Cl is passed out as gaseous HCl, leaving deposition of none corrosive sulphates. Recommendation is made to study this phenomenon in an experimental setting.

 

Biomass gasification technology integration with an internal combustion (IC) engine is also studied. Here requirements for the producer gas quality have been discussed. Some tests carried out with wood pellets and wood cylinders compared the yield of tar from the two physically different fuels.  Wood pellets were found to yield more tar than wood cylinders.

 

Economic analysis of biomass gasifier integrated with an IC engine running a generator of 100 kWe was carried out. Comparison with a diesel electricity generator of similar capacity was made for a scenario in Uganda over a project life of 20 years. Different Plant Capacity Factors (PCF) and fuel costs including subsidies were considered. The analysis showed that over long period of time biomass power plant was more beneficial than the diesel power plant at PCF over 40%. This is more pronounced with unsubsidized diesel fuel.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology , 2011. , 114 p.
Series
Trita-KRV, ISSN 1100-7990
Keyword [en]
Tar, Gasification, Biomass
National Category
Engineering and Technology
Research subject
SRA - Energy
Identifiers
URN: urn:nbn:se:kth:diva-48984OAI: oai:DiVA.org:kth-48984DiVA: diva2:459097
Presentation
2011-06-15, M3, KTH, Brinellvagen, Stockholm, 15:42 (English)
Supervisors
Funder
StandUp
Note
QC 20111206Available from: 2011-12-06 Created: 2011-11-24 Last updated: 2011-12-06Bibliographically approved

Open Access in DiVA

Olwa Lic Thesis(2947 kB)2950 downloads
File information
File name FULLTEXT01.pdfFile size 2947 kBChecksum SHA-512
eb09978c6bbc3bfeb1a9e42e887433c22aba1fcc0b55aa43c7508d04f4364a09a0fa58973e0d025a1292e89fd1f1bb33cbff94d0a0243f27ef6fd8ea9f0849ab
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Olwa, Joseph
By organisation
Heat and Power Technology
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 2950 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 364 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf