Przemysław Maziarka

I am a Ph.D. student at Ghent University in Belgium. My thesis subject is the building of a comprehensive model for biomass thermochemical conversion. My current work is related to the CFD modelling of the thermochemical conversion (pyrolysis) of a large, single particle of biomass. The installations I needed to perform experiments for the CFD model’s validation were available at BEST, one of the leading institutes in the field thermochemical conversion of biomass and single particle modelling.  

More importantly they have a Single Particle Reactor (SPR, Rig: BE4) [Fig. 1.].  

The research group at BEST  was very welcoming and helpful. My visit was thoroughly planned beforehand together with Stefan Retschitzegger. The administrative procedures were simple and straightforward, and I was able to start the experimental work the first day after arrival. As a first-time BRISK2 programme participant I was delighted to see it was so efficient. 

We made excellent use of time. For the investigation itself, beech wood cylinders with two different aspect ratios (Ø8x10mm and Ø8x16mm) were used. Within each size, particles were divided into two groups: raw and leached with citric acid. Leaching was performed to effectively remove all mineral matter from the feedstock. In total, four groups of samples were pyrolyzed at five different temperatures (300, 400, 500, 700 and 900oC) [Fig. 2.].  

In general, the procedure involved introducing each sample separately into the single particle reactor. The investigated sample was kept in the reactor at the selected temperature and with the appropriate inert gas flow until its conversion was complete [Fig. 3. or (3A,3B,3C)]. Afterwards, the sample had to be carefully removed, in order to not destroy the fragile, charred solid residue [Fig. 4A/4B]. 

For the model’s validation, we collected transient data changes of: gas flow, temperature (center and surface), mass loss and non-condensable + light condensable vapours (GC + FT-IR).  

The resulting bio-oils/tars were collected accordingly to the tar protocol [Fig. 5A/5B], in order to assess the composition and quantity of the heavy organic compounds. Besides the gathering of the model’s validation data, the solid char samples were collected and kept. The char samples were then kept to be analysed (also a part of my research) and the results used to investigate changes in the structural properties of biochar vs. the feedstock’s initial processing parameters.  

Data obtained should advance the knowledge of biomass thermochemical conversion and tailor-made biochar/carbonaceous material production [Fig. 6].  

The SPR setup allows for simultaneously gathering very complex dataset through the performance of only one experiment, so it is very efficient and comprehensive. 

In my three weeks at BEST, we covered the whole experimental matrix, plus additional repetitions to cover for partial loss of the sample or oxidation. In total, through 15 working days, we were able to perform 199 experiments, 79 more than was initially planned [Fig. 7].  

It was mostly due to thorough preparation and my direct supervisor Peter Sommersacher’s in-depth knowledge of the SPR setup. Peter solved all technical problems as soon as they appeared, so the schedule and experiments work ran smoothly. Moreover, Peter already had established data assessment procedures, thanks to which the raw data from all experiments is already pre-processed and ready for consolidation and investigation [Fig. 8]. 

Apart from the hard data and samples, I learned other things thanks to my visit to BEST through BRISK2. The most important was gaining practical knowledge of how to conduct and measure the single particle conversion process. This is very useful for a person who works with the construction of models. It gave me a necessary perspective and allowed me to identify certain discrepancies between the model and reality due to imperfections of experimental methods.  

Also useful was exchanging ideas and opinions on process. I was able to meet with the people who work at the forefront of my research field and talk with them about the ideas for my future work. It will definitely be fruitful in terms of the quality of my work and future joint publications.  

To summarise, this trip exceeded all my expectations. I was very positively surprised that whole visit, went so smoothly, especially the experiments. If all the partners of the BRISK2 programme operate like BEST does, I can say that I fully recommend and encourage to participate in the BRISK2 programme. It is a great opportunity for everyone, not only to perform high-quality research but also meet nice and helpful people, who are experts in the biomass conversion field.