Progress in low carbon technologies for large-scale coal-fired power plants

China’s total carbon emissions are approximately 11 billion tons, with around 40% of CO₂ being produced by the coal-fired power plants (CFPP). Therefore, reducing carbon emissions from the CFPP is critical in achieving the Dual-Carbon target. This paper focused on the advancements in the low-carbon/carbon-neutral fuel substitution technologies (such as biomass, sludge, hydrogen/ammonia, etc.) and the CCUS (carbon capture, utilization and storage). The CFPP coupled with biomass includes direct and indirect coupling, but are subject to the supply and price of biomass feedstock. To address these challenges, a comprehensive “planting-harvesting-transportation-storage-pretreatment-combustion” approach was recommended to ensure an effective control throughout the entire chain. Initial pilot test on a 660 MW CFPP revealed a substantial reduction in CO₂ emissions by 772500 tons annually. The high-water content of municipal sludge, reaching up to 80%, necessitates drying prior to entering the boiler. Current steam drying and flue gas drying technologies entail substantial investment and operational costs, with the dried sludge still retaining high water content and associated problems such as odor. Consequently, the blending ratio in the CFPP remains below 8%. A sludge carbonization technology based on a biomass heat source can address these challenges, which allows for the direct production of odorless sludge char in sewage plants with a calorific value of about 10.26 MJ/kg. This technology enables an increased blending ratio in the CFPP to 20%−30%, thereby significantly reducing coal consumption and CO₂ emissions. The blending of hydrogen/ammonia necessitates addressing the issues of ammonia escape and NO_x emission under high blending ratios. Experiments for co-firing of coal and ammonia were conducted on 300 MW and 600 MW CFPP in China to address the challenges of ammonia escape and NO_x emissions under high blending ratios. The results showed that combustion control can achieve a higher NH₃ burn-up rate with a slight increase in NO_x emissions. However, the commercialization of hydrogen/ammonia blending in the CFPP is constrained by the cost of hydrogen and ammonia. The commercialization of pre-combustion decarbonization technology, such as IGCC, faces significant limitations due to high costs. Several foreign demonstration projects were discontinued. The construction costs and equipment reliability are crucial for promoting the commercialization of this technology. Carbon capture technologies in combustion processes include oxygen-enriched combustion and chemical chain combustion. The power generation efficiency of atmospheric oxyfuel combustion is lower by 8%−12% compared to air combustion due to the energy consumption associated with air separation and recycling processes. Transitioning from atmospheric oxyfuel combustion to pressurized oxyfuel combustion can further increase the net power generation efficiency. Notably, China has constructed the world’s largest 4 MW chemical-looping combustion (LCL) demonstration plant. The LCL also has a potential application in the gasification industry. Post-combustion carbon capture predominantly employs the solution absorption technology, while the solid adsorption technology offers a lower regeneration energy consumption. However, some challenges remain in reducing energy consumption and costs to facilitate the large-scale commercialization of this technology.