Pyrolysis is increasingly used technique for obtaining valuable renewable carbon feedstock and recycle waste biomass and plastics. Â However, pyrolysis feedstock contains contaminating elements that are passed on to the pyrolysis oil phase. This makes crude pyrolysis oil reactive, unstable, corrosive and can lead to substantial challenges in downstream processes. The chemical composition of crude pyrolysis oil must also often be adapted to the intended end use. For example, the manufacture of sustainable aviation fuel (SAF) or sustainable polymers have their own specific requirements. To use pyrolysis oil safely and sustainably on a large scale, the crude pyrolysis oil requires upgrading by removing the contaminants and or chemically modify the composition towards its end use.Â
The technology for upgrading pyrolysis oil (or PyOil) is still in its early stages, primarily due to the fact that the pyrolysis process itself has not yet reached a mature and consolidated state. Currently, the common practice is to burn or landfill waste plastic and biomass, rather than harnessing their valuable molecular structures to produce virgin materials. This is mainly due to the fact that alternative proven processes are still under development and have not reached a large-scale, economically viable stage. Yet, we are on a turning point. Driven by new legislation, major players in the chemical and energy industries, along with research and development institutes, as well as numerous emerging companies, are intensifying their collaborative efforts in research and development. The aim is to ensure the production of sustainable products that comply with the new legislation and in a timely manner.
One promising approach to enhance the quality of pyrolysis oil is through adsorption. By contacting an oil with a suitable adsorbent, contaminants can be removed selectively. An example of this strategy is the reduction of halogen content using reactive adsorption at elevated temperatures and pressures.
Avantium R&D Solutions, a pioneer in renewable and sustainable chemistry, is dedicated to supporting its customers in pursuing their R&D goals by offering custom-made testing units. With Avantium’s custom-made testing unit, many samples can be treated simultaneously under the same process conditions. The required sample volume of each sample is small, which limits the total amount of required crude PyOil. This proves advantageous as the R&D pyrolysis units, that typically generate these crude PyOil samples are usually a small scale. Samples can be tested in batch, using only 2 mL crude PyOil per sample. With the capability to test several samples at once, it enables the screening of multiple adsorbents, carriers and porosities.
After the initial screening is completed in batch mode, the most promising adsorbent/carrier combinations can be tested on the same PyOil in flow mode. Utilizing Avantium’s method leverages to obtain as much accurate data as possible from a relatively small amount of crude PyOil sample, while simultaneously testing a significant number of samples. This is typically achieved using small diameter fixed bed adsorption columns under very well controlled process conditions. The adsorbents usually are pretreated using an appropriate method, and subsequently exposed to target conditions for a period of several days or weeks. Conditions for a liquid phase process in this domain are temperatures up to 400°C and pressures up to 180 bar. Halogen removal, like this case, is a reactive adsorption process in which the adsorbent is not regenerated. But in different applications multiple adsorption/regeneration cycles can also be part of the scope of testing. Test results indicate that a significant amount of contaminants can be removed by adsorption, rendering this in to a promising technique for further investigation and scale up.
Are you interested? As Avantium R&D Solutions, we can design and build your custom-made R&D unit for pyrolysis oil upgrading. Contact us for more information.