Technology of co-firing coal and biomass: features, current state, and prospects

Purpose. The research focuses on analysing the technology of co-firing biomass and coal (CFBC) as an effective method for reducing greenhouse gas emissions and partially transitioning to renewable energy sources. Particular attention is given to the application of this technology in the context of Ukraine, considering the energy challenges posed by the war and the need to modernise coal-fired power generation. Methodology. A comprehensive approach was employed in this study, combining the analysis of experimental and computational research. A systematic review of global experience with the implementation of co-firing technologies for coal and biomass was conducted using scientific databases covering the period from 2012 to 2024. The data obtained on global practices provided the theoretical basis for analysing research directions essential for implementing CFBC technology in Ukraine. Findings. The research revealed that CFBC technology is an effective method for decarbonising coal-fired energy production, particularly in coal-dependent countries such as Ukraine. The findings demonstrated that the optimal share of biomass in the fuel blend during direct pulverised combustion is approximately 10 %, which enables a reduction in NOx emissions by 3–17 % and SO2 emissions by 9 % without requiring significant boiler retrofitting. Furthermore, a synergistic effect was identified: during the co-pyrolysis of coal and biomass, the yield of volatile matter increased by 3–9 % compared to calculated values, significantly improving the ignition and combustion processes of anthracite. However, increasing the biomass proportion beyond 10 % in existing pulverised boilers results in higher unburned residues and may lead to slagging issues due to the high alkali metal content in biomass. Originality. This study provides a comprehensive analysis of CFBC technology within the context of Ukraine’s energy system, particularly for TPP-210A boiler type. It offers a detailed review of the synergistic effects arising from the combustion of blended fuels and substantiates optimal component ratios to minimise emissions. The research also establishes the optimal biomass content in existing pulverised boilers (up to 10 %), achieving a balance between environmental efficiency and the technological safety of the process. Practical value. The study demonstrates that CFBC technology is the most accessible and effective solution for the step-by-step decarbonisation of Ukraine’s energy system. The findings provide specific recommendations for modernising existing boilers without significant capital investments, including optimal ratios and methods for blending and feeding the fuel components. The research materials serve as a valuable resource for developing state programmes to support renewable energy, as they offer practical mechanisms for reducing CO₂ emissions by 5–20 % at pulverised power plants.