Plasma-Catalytic Processing of Biomass Gasification Tars

Biomass gasification produces tar-laden syngas that hampers downstream utilisation. Plasma-catalytic processing integrates a plasma source with heterogeneous catalysts to crack, reform and oxidise tar compounds at relatively low temperatures and ambient pressure. The reactive species generated by non-thermal plasmas—electrons, radicals and excited molecules—initiate bond scission in aromatic and polyaromatic tars, while catalysts lower activation energies and steer selectivity towards valuable gases such as hydrogen and carbon monoxide. Recent advances have explored diverse reactor architectures, from dielectric barrier discharge systems to gliding arc and microwave plasmas, coupled with metal-oxide supports to enhance surface discharge and maintain catalyst stability. Synergistic effects between plasma and catalyst manifest in improved energy efficiency, tar conversion and resistance to carbon deposition. This hybrid approach holds promise for decentralised biomass-to-hydrogen pathways and cleaner syngas production, contributing to decarbonisation across energy and chemical sectors.

Research from Nature Portfolio

A foundational investigation demonstrated the performance of a coupled gliding arc plasma-catalytic reactor employing an RANG-19PR catalyst for toluene conversion. At atmospheric pressure and in a simulated pyrolysis gas mixture, the hybrid system achieved nearly 90 % toluene conversion and significantly increased the calorific value of the treated gas. The study revealed that catalyst presence enhanced syngas quality by promoting methanation of CO₂ and CO, and mitigated carbon deposition through proposed radical-mediated pathways. This work exemplifies how plasma-catalysis can meet the minimal energy requirements for turbine and engine fuels while tackling tar removal in a single unit operation.

Plasma-Catalytic Processing of Biomass Gasification Tars publication trend

The graph below shows the total number of articles in plasma-catalytic processing of biomass gasification tars across all publications each year (not limited to Nature Index journals).

Technical terms

Non-thermal plasma: A partially ionised gas in which electron temperatures greatly exceed those of heavy species, generating reactive radicals and excited molecules without excessive thermal heating.

Dielectric barrier discharge (DBD): A plasma generation technique that employs one or more insulating layers between electrodes to produce uniform microdischarges at atmospheric pressure.

Syngas: A synthesis gas composed primarily of hydrogen and carbon monoxide, produced by gasification or reforming processes and used as a feedstock for fuels and chemicals.

Synergistic effect: Enhanced reaction performance arising from the interaction between plasma-generated species and catalyst active sites, leading to higher conversion or selectivity than either component alone.

References

1. Recent progress of low-temperature plasma technology in biorefining process. Nano Convergence (2023).
2. Coupled Plasma-Catalytic System with Rang 19pr Catalyst for Conversion of Tar. Scientific Reports (2019).
3. Plasma-Catalytic CO2 Reforming of Toluene over Hydrotalcite-Derived NiFe/(Mg, Al)O x Catalysts. JACS Au (2023).
4. Plasma-Catalytic Reforming of Naphthalene and Toluene as Biomass Tar over Honeycomb Catalysts in a Gliding Arc Reactor. ACS Sustainable Chemistry & Engineering (2022).
5. The Effect of Packing Material Properties on Tars Removal by Plasma Catalysis. Catalysts (2020).