Change search
ReferencesLink to record
Permanent link

Direct link
Katalytisk tjärreformering i förgasning av biomassa
KTH, School of Chemical Science and Engineering (CHE).
2015 (Swedish)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Catalytic Tar Reforming in Biomass Gasification (English)
Abstract [en]

Gasification of biomass is today facing several problems with the high amount of tar

produced and compounds such as alkali that can harm the catalyst in catalytic tar reformation.

This is why the focus in this master thesis study was to create a catalyst for secondary tar

steam reforming. The aim was to create a catalyst that was suitable for tar steam reforming

and also evaluate the effect that alkali had on the catalyst.

A catalyst composed of 20%Bronzes –ZrO2 impregnated with nickel was prepared in this

study and characterised with XRD and BET. The bronzes consisted of K0.25WO3 and was

prepared with two different methods and analysed with XRD to see if there was some

difference in the structure and purity. Three different weight loads of nickel: 5-,10- and 15

wt% , was prepared for each catalyst that was named Method 1 and Method 2. In total six

catalysts was tested in an experimental test rig that was situated at the Royal Institute of

Technology in Stockholm. In addition a blank test was performed for comparison of the

catalytic activity.

For the experiments 1-methylnaphthalene was decided to be used as a simulated tar. The

experiments were divided into two parts where in Part 1 a S/C ratio of 4 was used and Part 2 a

S/C ratio of 6 was used. The experiments were conducted at reactor temperatures of 700 °C

and 800 °C with or without alkali aerosols. Other parameters changed in the experiments were

the catalyst load, 1-methylnaphthalene flow and the gas hourly space velocity. Results were

analysed with 4 micro gas chromatographs and solid phase adsorption.

Results from the catalyst characterisation indicated that the wanted catalyst had been prepared

however in Method 2 a higher purity of the bronzes was reached compared to Method 1. The

results from the BET analysis gave a surface area of between 40-46 m2/g for the different


In the experiments from Part 1 a very high gas hourly space velocity was used and the results

indicated that there was almost tar reduction compared to the blank test. In Part 2 the gas

hourly space velocity was lowered and a higher tar reduction and was obtained. One test was

also conducted at 900 °C where the highest tar reduction was obtained, almost 40 %.

From the results it could be seen tar reduction and 1-MN/naphthalene ratio was increasing

with higher temperatures and nickel loadings. Catalysts prepared from Method 2 also showed

a higher tar reduction and 1-MN/naphthalene ratio compared to Method 1which could

indicate that it was more stable and had a higher purity of the bronzes. The results from

atomic absorption spectrophotometer showed that the mass of potassium in the catalyst before

the experiment decreased between 3-29 % compared to after the experiment. From the rather

low decrease in potassium the hexagonal structure of the bronzes clearly protects the

potassium from evaporating within the bulk. Also introducing alkali aerosols had a positive

effect on the tar reduction.

Place, publisher, year, edition, pages
2015. , 74 p.
National Category
Engineering and Technology
URN: urn:nbn:se:kth:diva-172333OAI: diva2:846859
Available from: 2015-09-21 Created: 2015-08-18 Last updated: 2015-09-21Bibliographically approved

Open Access in DiVA

fulltext(2036 kB)45 downloads
File information
File name FULLTEXT01.pdfFile size 2036 kBChecksum SHA-512
Type fulltextMimetype application/pdf

By organisation
School of Chemical Science and Engineering (CHE)
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 45 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

Total: 19 hits
ReferencesLink to record
Permanent link

Direct link