The production of biodiesel has long been based on raw materials extracted from rapeseed, maize and palm oil and the objections against such have been dominated by opposition to using food and agricultural land for the production of fuel.
However, biofuel can also be produced from sustainable sources such as forests and the waste derived from forestry, industry and households, since the raw materials used are regarded as being waste products. This is what researchers at the USN are wanting to investigate in more detail.
"Norway has never had much biofuel since we have always had oil, but our oil production and resources are now declining and we want to use renewable sources of energy. Furthermore, the concept of diesel is a tricky one, so it is difficult to sell it, but in this project we are turning biodiesel into an eco-friendly fuel", says Associate Professor Marianne Sørflaten Eikeland. She and Professor Britt Margrethe Emilie Moldestad have received research funding for working on this project.
The project is entitled “FLASH - Predicting the FLow behaviour of ASH mixtures for the production of transport biofuels in the circular economy” and it was granted NOK 9.9 million by the Research Council of Norway under the ENERGIX Programme in 2017.
Ash is the problem
The researchers are embarking on this challenge by gassifying wood to produce synthesis gas. This process takes place by heating the wood to a high temperature so that it is converted into a gas mixture consisting of hydrogen (H2) and carbon monoxide (CO). This gas mixture provides a good feedstock for the further production of hydrocarbons.
Ash is a byproduct of the gassification process. The ash in gassification reactors presents major challenges, and the key to success is identifying and resolving these problems.
"Our aim is to test different processes and we will find the process which is most suitable for producing biofuel, although the ash is a problem in this process", says Ms Moldestad.
The type of ash produced in gassification reactors varies depending on the type of reactor used. The problem with some types of reactors is that the ash melts and forms agglomerates (lumps) which upset the effectiveness of the reactor. In other types of reactors the ash is supposed to melt and run out of the reactor. The problem with this is that the ash becomes too viscous with poor flow characteristics, thus reducing the effectiveness.
"Ash has different properties depending on the composition of the biomass, and the ash derived from different biomass mixtures will be investigated in this project. This will be done by conducting experimental trials and analyses, and methods and models will be developed in order to predict accelerated problems relating to different biomass mixtures", says Ms Moldestad.
Overall FLASH will provide a valuable contribution for improving the effectiveness of gassification by reducing the challenges that are associated with ash, and thus help to speed up the conversion of biomass into biofuel via gassification.
There are currently two doctoral students working on gassification: Cornelius Agu and Janitha Bandara. These two researchers are also in the process of employing another doctoral student who will work directly on the problems associated with ash.