On 12 May, the HYIELD project hosted a webinar titled “Gasification of different biomasses in a bubbling fluidized bed reactor: influence of process variables on gas yield and composition.” Around 60 participants joined from research and industrial backgrounds, and the session generated a focused Q&A of mostly technical questions, which showed the audience’s expertise and clear focus on the practical and scientific aspects of biomass gasification within the HYIELD framework.
This webinar forms part of HYIELD’s broader mission to accelerate the transition towards clean hydrogen production from biogenic waste streams, demonstrating innovative solutions that combine advanced gasification, syngas cleaning, and hydrogen purification into a single integrated value chain.
What is gasification and why does it matter?
The session opened with an introduction to the HYIELD project by Andrés Viedma from Magtel. Ramón Murillo from the Instituto de Carboquímica (CSIC) then gave a thorough overview of gasification as a thermochemical process that converts biomass and waste into syngas, a versatile mixture of hydrogen (H₂), carbon monoxide (CO), carbon dioxide (CO₂), methane (CH₄) and light hydrocarbons.
With over 200 years of development behind it, gasification is a well-understood technology, and its ability to process waste streams makes it a practical route for producing renewable hydrogen while keeping carbon in productive use rather than releasing it.
Why Bubbling Fluidized Bed Reactors?
A central focus of the webinar was the use of bubbling fluidized bed (BFB) reactors, a preferred configuration for biomass gasification due to their:
- Excellent gas–solid mixing, ensuring uniform temperature distribution
- Flexibility to handle heterogeneous feedstocks, including waste-derived materials
- Enhanced heat transfer and reaction efficiency
These advantages make BFB reactors particularly suitable for HYIELD’s goal of processing diverse biogenic waste streams at scale.
How process variables affect performance
One of the most valuable contributions of the webinar was the detailed analysis of how operating conditions influence gasification performance.
Temperature:
Temperature is one of the most influential parameters. Raising it from 650°C to 850°C increased gas yield and carbon conversion noticeably and reduced tar formation. Overall hydrogen output rose even when hydrogen concentration within the gas mix fluctuated.
Steam-to-carbon ratio (S/C)
The S/C ratio affects reaction pathways. Higher steam promotes reforming and reduces hydrocarbons, though at lower temperatures the kinetics limit hydrogen formation. Above an S/C of roughly 2, both gas yield and hydrogen production improve.
Feedstock type
The webinar highlighted strong differences between biomass types: lignocellulosic feedstocks (e.g., olive stones, grape seeds) show varying reactivity and tar production, while structurant biomass demonstrated cleaner gas and better overall performance. Sewage sludge produced high hydrogen concentrations but came with significantly higher tar and sulfur levels.
These findings underline the importance of tailoring gasification conditions to each feedstock.
The HYIELD Perspective
The webinar also placed the experimental work within the broader HYIELD framework. The project aims to demonstrate a multi-stage steam gasification and gas separation process capable of producing high-purity hydrogen (>99.97%) from waste streams.
The process converts waste into raw syngas through gasification, cleans and conditions the gas to remove contaminants, then separates and purifies the hydrogen for industrial use. This integrated concept is being validated at demonstration scale, with cement production among the target applications.
Watch the full webinar here: https://youtu.be/qn0ObVzM-lI?si=BacX92Q46_02EAIZ
The presentations from the session are available here:
The project is Co-founded by Clean Hydrogen Partnership and European Commission.
Writer: Laia Mencia
Editorial: Lucía Salinas
May, 2026