In a groundbreaking study published in *Meitan xuebao* (translated to *Coal Science*), researchers from Xi’an Jiaotong University have demonstrated the feasibility of co-firing biomass pellets with coal in large-scale power plants, offering a promising pathway to reduce carbon emissions while maintaining operational efficiency. The research, led by Fuxin Yang from the School of Energy and Power Engineering, could reshape the energy sector’s approach to integrating renewable energy sources into existing infrastructure.
The study, conducted at a 660 MW ultra-low emission coal-fired power plant, explored two combustion modes for co-firing Salix psammophila biomass pellets: “single mill and single burning,” where biomass is pulverized separately, and “single mill and mixed burning,” where coal and biomass are co-pulverized together. The findings reveal that biomass pellet co-firing can be achieved using existing pulverization and combustion equipment, a significant breakthrough for the industry.
“Our results indicate that the HP coal mill demonstrates excellent adaptability to biomass pellets, meeting all operational requirements,” said Yang. “The operating current of the mill is lower when the biomass is milled alone or with coal, which is a notable efficiency gain.”
The research highlights several key advantages of co-firing biomass. In the “single mill and single burning” mode, a biomass feed rate of 15 to 20 tons per hour is recommended, while a biomass co-firing ratio of 3% to 5% is optimal for the “single milling and mixed burning” mode. The study found that co-firing biomass slightly decreases furnace temperature by about 15 to 32 degrees Celsius, but the temperature of flue gas at the air preheater inlet remains relatively unchanged. Importantly, the thermal efficiency of the boiler stays within the range of 92.83% to 93.93%, nearly equivalent to the thermal efficiency under pure coal conditions.
One of the most compelling findings is the potential for co-firing biomass to reduce NOx emissions. “Oxygen content is a key factor influencing NOx formation,” explained Yang. “By adjusting the air supply parameters, co-firing biomass can significantly reduce the formation of NOx, which is a major environmental benefit.”
The study also examined the characteristics of fly ash produced under various conditions. The fly ash generated with “single mill and single burning” meets the strength activity index requirements, with values exceeding 70%, making it suitable for use in building materials. This finding opens up new commercial opportunities for the energy sector, as the fly ash can be repurposed, adding value to the co-firing process.
The implications of this research are far-reaching. By demonstrating that biomass can be co-fired with coal in large-scale power plants without compromising efficiency or increasing emissions, the study provides a viable strategy for reducing carbon footprints while leveraging existing infrastructure. This approach could accelerate the transition to renewable energy sources, making it an attractive option for energy providers looking to meet sustainability goals.
As the energy sector continues to evolve, the integration of biomass into coal-fired power plants could become a standard practice, driven by the need for cleaner energy solutions. The research published in *Meitan xuebao* offers a roadmap for this transition, highlighting the technical feasibility and environmental benefits of co-firing biomass.
For the energy sector, this research represents a significant step forward in the quest for sustainable energy solutions. By co-firing biomass with coal, power plants can reduce their carbon emissions while maintaining operational efficiency, a win-win scenario for both the environment and the industry. As Fuxin Yang and his team continue to explore the potential of biomass co-firing, the energy sector can look forward to a future where renewable energy sources play an increasingly central role.