How does a circulating fluidized bed boiler achieve efficient denitrification and desulfurization through low-temperature combustion and the addition of a desulfurizer?
Publish Time: 2025-07-31
In modern energy conversion and industrial heating, the circulating fluidized bed boiler (CFB) has long surpassed traditional combustion equipment, becoming a model for efficient, clean, and flexible energy utilization. More than just a boiler, it's a complex system integrating combustion science, thermodynamics, materials engineering, and environmental control. It represents a crucial step toward sustainable coal-fired and multi-fuel utilization technologies. Its core lies in the synergistic effects of "circulation" and "fluidization." By suspending solid particles in the airflow and repeatedly circulating them for combustion, it achieves deep fuel utilization and source control of pollutants.The core value of the circulating fluidized bed boiler lies in its extraordinary adaptability to low-quality fuels and its excellent environmental performance. While traditional boilers often rely on high-quality coal with high calorific value and low impurities, CFB boilers can efficiently burn low-calorific-value, high-ash, high-moisture, or difficult-to-burn fuels such as lignite, coal gangue, oil shale, biomass, municipal solid waste, and even industrial waste. This is due to their unique fluidized combustion environment: fuel particles are "boiling" in the high-velocity airflow, thoroughly mixing with the air and maintaining a low combustion temperature range of 850–950°C. This temperature window maintains efficient combustion while effectively suppressing the formation of nitrogen oxides (NOx), avoiding the large-scale generation of high-temperature thermal NOx. Furthermore, desulfurization agents such as limestone can be added directly into the furnace, reacting with sulfur in the fuel during combustion to achieve desulfurization efficiencies exceeding 90%, significantly reducing SO₂ emissions and truly achieving the goal of "eating coarse grains, emitting clean air."The innovation of circulating fluidized bed boilers lies not only in their combustion efficiency but also in their deep optimization of energy cascade utilization and system integration. The high-temperature flue gas produced by CFB boilers is not only used to generate steam to drive turbines for power generation or heating, but the large amount of high-temperature circulating ash it carries also contains considerable physical heat energy. Through external heat exchangers or return material conditioning, this heat can be effectively recovered for use in preheating air, feedwater, or driving other processes, significantly improving overall thermal efficiency. Furthermore, CFB boilers offer a stable combustion process, a wide load regulation range (stable operation between 30% and 100% of rated load), and fast response times, making them ideal for grid peak regulation and addressing load fluctuations in industrial production, enhancing the flexibility and resilience of the energy system.Circulating fluidized bed boilers demonstrate strong economic and strategic value. In regions with abundant but low-quality coal resources, CFB technology transforms previously unusable "waste" into valuable energy, reducing fuel costs and improving resource utilization. In industries such as power generation, cogeneration, papermaking, chemicals, and metallurgy, it provides a stable and reliable heat source and power for energy-intensive production processes. Especially in the field of municipal waste incineration power generation, CFB boilers, with their advantages such as low-temperature combustion that suppresses dioxin production, strong fuel adaptability, and resource-based ash utilization, have become a key technological path for achieving "harmless, reduced, and resourceful" waste treatment.Even more thought-provoking is the potential role of circulating fluidized bed boilers in promoting energy transition and carbon emission reduction. With the advancement of carbon neutrality goals, CFB boilers are actively exploring integration with carbon capture and use (CCUS) technology. Their lower flue gas temperatures and higher CO₂ concentrations (compared to traditional pulverized coal boilers) provide more favorable conditions for subsequent carbon capture. Furthermore, their compatibility with biomass fuels offers the potential for transitioning to co-firing or even full-firing of biomass, gradually reducing carbon emissions intensity. In the future, combined with intelligent control systems and big data analytics, CFB boilers are expected to achieve real-time optimization and predictive maintenance of the combustion process, further improving operational efficiency and environmental performance.Though a giant industrial structure, circulating fluidized bed boilers carry a profound balance between resources, the environment, and efficiency. It uses a "boiling" bed to digest low-quality fuel, "circulating" ash particles to recover waste heat, and "low-temperature" combustion to protect blue skies. In an era of pursuit of clean, efficient, and sustainable energy, it is providing indispensable power support for modern industrial civilization in a solid and intelligent way, becoming a silent yet powerful cornerstone in the transformation of the energy structure.
