If you missed the third episode of the EBIO webinar series, or you would like to watch it again, the full recording is available here:
The webinar welcomed more than 100 guests online and received more than 10 questions.
A recap of all the questions and answers can be found here:
1. What are the most important requirements for pyrolysis oil to be “refinery-friendly”?
- Reduced Oxygen Content – Lower the oxygen content through processes like hydrodeoxygenation to reduce acidity and improve stability.
- High hydrogen to carbon molar ratio – For the desired product to have a high hydrogen to carbon (H/C) molar ratio (e.g., 1.7-1.8 for gasoline and diesel pools), it is advantageous to start with a high initial H/C ratio. This facilitates the production of on-spec products more easily. In refineries, there are two main strategies to achieve this: (1) Addition of Hydrogen in Upgrading Processes: Processes such as hydrotreatment add hydrogen to increase the H/C ratio. Utilizing pyrolysis oil with a high H/C ratio reduces the need for additional hydrogen, thereby improving the overall economics of these costly processes. (2) Removal of Carbon in Conversion Processes: Processes like catalytic cracking (FCC) remove carbon to adjust the H/C ratio. However, pyrolysis oil with a too low H/C ratio can lead to the production of low H/C ratio products, such as aromatics, polyaromatics, and coke. These by-products can negatively impact the activity, stability, and selectivity of the FCC catalyst.
- Low Water Content – Minimize water content to avoid phase separation and deactivation of hydrotreatment catalysts polishing the fuel properties.
- Homogeneous Composition & consistent quality – Ensure a consistent and stable composition to facilitate blending in co-processing with conventional feedstocks
- High Thermal Stability: – Enhance thermal stability to prevent decomposition and polymerisation during high-temperature refinery processes.
- Compatibility with Existing Equipment: – High acidic content of direct fast pyrolysis liquids may cause metallurgical problems with already existing refinery pipes, reactors, distillation columns and storage tanks. Since refineries are running very risky operations and safety is very first, any leak may cause very devastating results. Reduced acidity that can be handled with existing equipments ensuring no or minor effect on wear, corrosion, or fouling of refinery equipment.
2. Should a high-quality fuel have a higher content of isoparaffins or n-paraffins, and why?
For jet fuel (aviation fuel) since the operability at high altitudes at low temperatures are must, cold flow properties are very important.Isoparaffins have lower freezing points compared to n-paraffins with the same carbon number due to their branched structures and reduced van der Waals molecular interaction.
For gasoline isoparaffins also have positive effect on octane number, a standard measure of a fuel’s ability to withstand compression in an internal combustion engine without undergoing pre-ignition. The higher the octane number, the more compression the fuel can withstand before detonating.
Olefin content is not generally wanted in fuels due to higher reactivity and tendency to gum formation leading improper physical properties
For diesel n-paraffins contributes to cetane number since their auto-ignition points are lower than isoparaffins.
Olefin content is not generally wanted in fuels due to higher reactivity and tendency to gum formation leading improper physical properties.
3. NiMo and CoMo catalysts were discussed. The study also used alumina-supported NiMo catalysts. Why did you choose this support material?
For jet fuel maximization by hydroprocessing of pyrolysis liquids support materials with moderate acidity is preferred in order not to cause overcracking.
Alumina is resistant to high temperatures and has high thermal stability. This allows the catalyst to operate without degradation in hydroprocessing reactions that require high temperatures.
4.How long were you able to run the hydrotreating test? It seems the catalyst is strongly deactivated after few days.
We have not yet conducted long-term testing. Therefore, we could not fully observe the deactivation of the catalyst. For now, we are trying 5-6 hour tests. We will increase performance tests in the coming period and look for the exact answer to this question.
5 . What is the cycloparaffin content in the fuel?
The cycloparaffin content in fuel varies depending on the type of fuel and its source. For instance:
Gasoline: Typically, cycloparaffin content can range from 10% to 40% by volume.
Jet Fuel: Cycloparaffin content can be higher, often between 20% to 30%.
Diesel Fuel: Cycloparaffin content is usually lower, ranging from 5% to 10%.
6. Do you think it would be possible to continue the reaction at 90 bar pressure? Is it economically viable reaction?
Knowing that the hydrogen pressure for the hydrotreatment of vegetable oil typically ranges from 30 to 100 bar to ensure efficient hydrogenation reactions, which convert triglycerides and free fatty acids into desirable hydrocarbon products like renewable diesel and jet fuel, using a reaction pressure of 90 bar is not a significant issue for refiners and can be economically viable. The main advantage of the EBIO proposal is the use of extremely cheap and highly available biomass, such as forest residues, which should ensure the economic feasibility of the proposed value chain.
7. How did you remove the water from oil before upgrading?
Draining is one of the initial options to be performed by physical observation. After that distillation and fractionation help reducing the water content in some of the boiling point cuts. Alternatively liquid-liquid extraction with a polar organic solvent with low boiling point may help.
8. I am interested in the electrochemical upgrading of biooil. Could I get some more information such as experimental conditions or any published papers?
Several publications are being drafted. Publications of the consortium partners you can find below:
Peroxodicarbonate as a Green Oxidizer for the Selective Degradation of Kraft Lignin into Vanillin Michael Zirbes, Dr. Tobias Graßl, Rieke Neuber, Prof. Dr. Siegfried R. Waldvogel
https://doi.org/10.1002/anie.202219217
Comprehensive valorisation of technically relevant organosolv lignins via anodic oxidation
Manuel Breiner Michael Zirbes and Siegfried R. Waldvogel
https://doi.org/10.1039/D1GC01995C
Investigating the platinum electrode surface during Kolbe electrolysis of acetic acid Margot Olde Nordkamp, Talal Ashraf, Marco Altomare, Andrea Casanova Borca, Paolo Ghigna, Tatiana Priamushko, Serhiy Cherevko, Viktoriia A. Saveleva, Cesare Atzori, Alessandro Minguzzi, Xiufang He, Guido Mul, Bastian Mei
https://doi.org/10.1016/j.surfin.2023.103684
The Impact of Cations on the Selectivity of Pt Electrodes in the Electrochemical Oxidation of Acetic Acid Talal Ashraf, Guido Mul, Bastian Mei
https://doi.org/10.2139/ssrn.4592318
9. How do you rate the pretreatment technology (electrochemical upgrading), if using a trl level between 1-9?
We target TRL 4 at the end of the project and have currently operate three bench scale units at this TRL.
10. What about energy demand required for those upgrading processes from biooil to refinery friendly liquid
It is difficult to estimate for now since the EBIO is a lab scale (TRL 3-4) project and far from economies of scale. The level of upgrading relies on the downstream process to be utilized further with blending with fossil cut since each downstream process has its own specific processing limits.
However, it is important to mention that electrochemical upgrading is conducted under mild operating conditions, specifically at low temperatures (30-60ºC) and with high faradic efficiency. This means that electrochemical upgrading is less energy-intensive compared to traditional upgrading processes, such as the direct hydrotreatment of pyrolysis oils. This strategy is therefore advantageous for producing refinery-friendly biocrudes.