My experience at KTH, Sweden

Biofuels Research Infrastructure
for Sharing Knowledge
CASE STUDY
My experience at KTH, Sweden
Alen Horvat of the
Carbolea Research Group
at the University of
Limerick, Ireland, outlines
his visit to the Royal
Institute of Technology
(KTH) in Sweden
Carbolea is a young and ambitious research group
based at the University of Limerick, Ireland. Its main
research area is lignocellulosic and waste biomass
conversion via processes such as gasification,
pyrolysis, hydrolysis, and catalytic upgrading of
intermediate products. The gasification team consists
of four-five researchers operating a large lab scale
bubbling fluidised bed gasifier with a feeding rate of
approximately 3kg. My own research focus is on the
effects of process conditions on tar composition,
particularly tar sampling, post sampling and final
instrumental analysis.
I felt that it would be useful for me to research
alongside other gasification experts, and I also wanted
hands on experience working with other gasifiers and
particularly working using different tar sampling and
analysis techniques. KTH is a leading gasification
centre and seemed to offer the opportunity for both. My
experimental plan was to investigate the effect of
biomass pretreatment (torrefaction) on tar composition.
The proposed study on gasification of non-torrefied and
torrefied Miscanthus Gigantheus was approved for the
duration of two weeks, and in September 2014 a team
of three Carbolea researchers travelled to Stockholm.
The team used a top fed fluidised bed reactor with a
high temperature filter (also called an LDU) and a
feeding rate of 3-4kgh-1 during the experimental
campaign. The LDU enabled upscale continuation of
our previous study of torrefied biomass – previous
studies were conducted on a smaller test rig with a
feeding rate of approx. 0.5kgh-1 and side screw
feeding.
Figure 1: Biomass preparation sieving.
Figure 2: SPA sampling.
The study visit included feedstock preparation (i.e.
shredding, sieving), large lab scale gasifier operation
(i.e. testing the feeding system, maintenance work
between tests), and Solid Phase Adsorption (SPA) tar
analysis. Since this was the first time torrefied biomass
Figure 3: Adjusting the feeding hopper.
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Biofuels Research Infrastructure
for Sharing Knowledge
CASE STUDY
My experience at KTH, Sweden
had been gasified at KTH we had to deal with issues
such as adjusting the steady feeding rate, char
accumulation in the bed, sintering etc. The gasifier
operated under atmospheric conditions as opposed to
well-developed pressurised tar sampling, which created
new challenges. For that reason modifications of the tar
sampling point were necessary during the first week of
operation.
Iraj Bavarian (one of KTH’s analytical chemists) kindly
shared his experience in conducting SPA tar analysis
and I showed him the methods we use within the
Carbolea group. As a young gasification researcher it
was exciting to be working at an organisation where
gasification and tar analysis have a long history.
Our full experimental plan could not be completed due
to time consuming modifications and adjustments at the
beginning of the visit. Three tests using torrefied
biomass were conducted while non-torrefied biomass
still needs to be tested in order to compare the two
types of biomass. Therefore, another visit to the facility
has been proposed, due to take place in 2015.
BRISK Transnational Access remarkably accelerates
knowledge transfer in the field of bioenergy, by making
available research facilities across recognised
organisations accessible to young researchers. This
was Carbolea’s third participation in the BRISK project,
and BRISK enhanced my individual research
experience significantly.
Figure 4: Extraction of SPA cartridges.
The benefits I gained from the BRISK Transnational
Access experience would not have been possible
without the welcoming and helpful personnel at KTH:
Christer Rosén, Mikael Lundgren, Klas Engvall and Iraj
Bavarian. I would also like to acknowledge my
colleagues from Carbolea; Marzena Kwapinska and
Natalie Taupe who worked alongside me during the
visit.
Thank you and I look forward to my participation in
2015.
Figure 5: Marzena Kwapinska and Natalie Taupe.
Contact
www.briskeu.com
Andrew Martin
Royal Institute of Technology (KTH)
E: andrew.martin@energy.kth.se
W: www.kth.se
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