2016-09-30 08:00

More efficient gasification of biomass with new catalysts

If metals are used when biomass undergoes gasification, the process can be more effective. For example, it may be possible to get rid of tar at lower temperatures. Tar risks destroying the equipment and reducing efficiency. Abas Mohsenzadeh at the University of Borås will examine how metals affect the process.

Abas MohsenzadehWhen biomass undergoes gasification to become biofuels, tar is often produced. Tar has different compositions depending on the biomass it comes from, but adheres to pipes and other equipment. To get rid of tar, the boiler must be heated to very high temperatures, up to 1,200 degrees.

“The higher the temperature, the more tar is destroyed’, says Abas Mohsenzadeh, a Days of Knowledge
To fund the "Novel catalysts for metal catalyzed tar cracking" project, Sparbanksstiftelsen Sjuhärad is providing SEK 185 000. This money will be awarded on 19 October at Days of Knowledge, a ceremony at which the University of Borås honours reserach and education. The event is arranged by the University of Borås, City of Borås, Sparbanksstiftelsen Sjuhärad and Swedbank Sjuhärad.
researcher at the University of Borås. ‘But it takes a lot of energy to heat up the boiler to such high temperatures. This is what catalysts may be able to change – they are added to accelerate the reaction, and in this case affect the tar so that it reacts at a lower temperature.”

Nickel and other metals are already used as catalysts in gasification. But the area is not particularly well-investigated; so far, detailed knowledge is missing about what actually happens at the atomic and molecular levels when a catalyst is added and which catalysts work best.

That’s what Abas Mohsenzadeh’s research will change.

“I do computer simulations to investigate in detail what happens and why’, he says. ‘Then I test catalysts against different compositions of tar and see if the catalysts change the reactions in some way. What I have noted is that they, to different degrees, affect how rigid or elastic the bonds that hold the atoms together in the tar are. When the bonds are more elastic, less energy is needed, that is to say heat, for them to loosen in order for the tar to react. I want to find catalysts that make them more elastic.”

To begin with, he is investigating in what way catalysts in the form of pure metals affect different types of tar; then he can go further and test different alloys and even metal oxides in different variations.

“I hope to be able to find stable catalysts that tolerate these high temperatures without being destroyed or working less effectively. When I have found that via my computer simulations, I can begin tot experience with different equipment and finally in actual boilers. The computer simulations make it possible to take quicker and more energy-effective steps forward so that we don’t have to test everything; rather, can focus on the ones that have the most likely qualities. The end goal is to be able to create useable renewable energy.”