Scientists eliminate tar in gasification

As the global demand for sustainable energy solutions continues to grow, Lithuanian researchers have taken a step forward by developing a technology that not only transforms waste into valuable hydrogen but also eliminates a long-standing issue in gasification—the presence of tar. This new method offers an efficient and eco-friendly way to produce high-purity hydrogen from various waste materials, representing a significant advancement in clean energy production.

Hydrogen is a key element in the transition to cleaner energy. However, conventional gasification methods are often unable to ensure its high purity—synthesis gases contain very low concentrations of hydrogen.

This inefficiency limits the industrial application of hydrogen as a clean gas fuel, highlighting the need for more advanced production methods.

To address this, Kaunas University of Technology (KTU) and Lithuanian Energy Institute (LEI) scientists have developed a two-step conversion system: an updraft gasifier followed by a catalytic reforming reactor.

The work is published in the journal Energy.

Increased hydrogen production

The process begins with gasification, where waste is heated in a controlled steam-oxygen environment to produce syngas, also known as synthetic gas.

“Gasification treatment is an emerging, promising, and eco-friendly technology that can convert waste into syngas as a major product besides soot as a by-product,” says KTU Chief researcher Dr. Samy Yousef.

However, the produced syngas contains tar, which not only reduces efficiency and can damage equipment due to corrosion effects, but also interferes with hydrogen production by affecting key chemical reactions. To solve this, the syngas is passed through a catalytic reforming reactor to break down the tar into smaller molecules. These catalysts also enhance chemical reactions that increase the hydrogen content of the syngas, reaching up to 60 vol%, making it a cleaner and more efficient fuel source.

According to the KTU expert, a crucial factor in this technology is the choice of catalysts used in the reforming reactor. That is why researchers tested most commercially available catalysts and laboratory-developed options.

“Experimental results demonstrated the technology’s efficiency under various conditions. Among the tested catalysts, KATALCO 57-4GQ proved to be the most effective, as its high surface area, stability, and durability played a key role in breaking down tar and enhancing hydrogen production,” says Dr. Yousef.

Can be applied to all types of waste

Unlike conventional gasification techniques, which require high-energy plasma systems or complex pressure-based processes, this new method operates at atmospheric pressure. This reduces the need for high-cost infrastructure and enhances operational safety.

Compared to the dominant hydrogen production method, steam methane reforming (SMR), this new approach offers a more energy-efficient and environmentally sustainable alternative. SMR relies on natural gas, a non-renewable resource, and emits large amounts of carbon dioxide, making it less viable for long-term sustainability goals.

“Unlike SMR, which operates under extreme conditions and requires high-pressure reactors, our method works at atmospheric pressure and utilizes waste as a cost-effective and renewable raw material, making it a cleaner solution,” says Dr. Yousef.

While the initial research focused on medical waste, the technology has the potential for broader applications. “This technology is versatile and can be applied to various types of organic and industrial waste, including plastics, textiles, and biomass. Before processing, the waste must be collected, sorted, and pre-treated to ensure a consistent composition and size, allowing for more efficient conversion,” KTU expert explains.

When discussing industrial implementation, the researcher highlights that this innovation has reached Technology Readiness Level 5 (TRL5). This level is part of a globally recognized scale that measures a technology’s maturity.

“Being at TRL5 means the technology has been tested in an environment that simulates real industrial conditions using reactors that closely resemble industrial-scale systems and is progressing toward full-scale deployment,” says Dr. Yousef.

As research continues, further scaling and optimization could pave the way for commercial implementation, making sustainable hydrogen production a reality in the near future.