在碳达峰、碳中和目标背景下，我国正加快构建新能源占比逐渐提高的新型电力系统，目前煤电正是消纳可再生能源大规模并网的最经济调节电源。循环流化床锅炉机组因自身天然优势在煤电深度灵活调峰中担任重要角色，但其独特的结构和运行方式导致变负荷速率偏低，消纳高比例新能源并网的能力亟待提高。分析了制约循环流化床锅炉变负荷速率的影响因素，包括气固两相流动的惯性、炉侧水侧传热的惯性、固体颗粒燃烧的惯性、水动力安全性、机炉动态匹配问题等，并解释了产生惯性的物理机制。归纳了提高循环流化床机组快速变负荷能力的关键技术，通过加快流动参数、提高传热系数、减小炉侧热容、增强炉侧水侧间的传热、强化燃烧反应、优化控制策略等方法，考虑工业尺寸锅炉的可行性，提出了一套综合优化技术方案，即“智能吞吐”系统的设想。在1台135 MW循环流化床锅炉上进行验证，结果表明，锅炉平均变负荷变化率可提升16%，最大负荷变化率短时间内可持续达到4%／min 左右。在此基础上，对宽负荷灵活运行的循环流化床锅炉机组的设计思路进行展望，用数据驱动热力系统动态模型，融合创新技术的热力系统多时空匹配运行技术，构建“ 三自一体” 的先进协同控制系统，并参考成熟的煤粉炉蓄能利用技术，为将来实际工业应用提供理论指导。

In the background of the carbon peaking and carbon neutrality goals, China is accelerating the construction of a new power system in which the proportion of new energy sources is gradually increasing, and coal-fired power plants are currently the most economical regulating power sources for the large-scale grid connection of renewable energy. Due to their inherent advantages, circulating fluidized bed boiler units are crucial for the deep and flexible peaking of coal-fired power plants. However, because of their peculiar design and mode of operation, these units have a low load change rate, making it necessary to increase their capacity to absorb large amounts of new energy for the grid. The influencing factors that governed the load change rate of circulating fluidized bed boilers were analyzed including the inertia of gas-solid two-phase flow, combustion of solid particles, heat transfer between the water side and the furnace side, hydrodynamic safety, dynamic matching problem of the turbine and boiler, and the physical mechanism of inertia generation was also explained. The key technologies to improve the rapid load change capability of the circulating fluidized bed unit were summarized. By accelerating the flow parameters, improving the heat transfer coefficient, reducing the heat capacity of the furnace side, enhancing the heat transfer between the furnace and the water side, strengthening the combustion reaction, optimizing the control strategy, and considering the feasibility of industrial size boilers, a comprehensive optimization technology solution was proposed, namely the concept of an "intelligent take in/out" system, which was validated in a 135 MW circulating fluidized bed boiler. The results indicate that it is possible to enhance the boiler′s average load change rate by 16% and sustain a short-term maximum load variation rate of up to 4%/min. According to this, using a data-driven dynamic model of the thermal system, a multi-temporal matching operation technology of the thermal system incorporating innovative technologies, an advanced collaborative control system with "three self-integrated", and a reference to the established energy storage and utilization technology of pulverized coal-fired power plants, the design idea of a circulating fluidized bed unit with flexible operation at a wide range of load was provided, which offered theoretical guidance for future practical industrial applications in China.

0 引言

1 循环流化床锅炉机组灵活性提升的重要性

   1.1 电力结构

   1.2 灵活性政策

2 循环流化床锅炉机组快速变负荷研究现状

   2.1 外部辅助系统优化

   2.2 热力系统优化

3 循环流化床锅炉机组变负荷速率影响因素

   3.1 流动惯性分析

   3.2 传热惯性分析

   3.3 燃烧惯性分析

   3.4 水动力安全分析

   3.5 机炉匹配问题

   3.6 小结

4 循环流化床锅炉快速变负荷运行关键技术

   4.1 流动参数和传热系数变化速率加快措施

   4.2 炉侧热容减小措施

   4.3 炉侧与水侧间传热能力增强措施

   4.4 燃烧反应速率强化措施

   4.5 机组灵活运行智能控制措施

   4.6 综合优化技术方案

   4.7 宽负荷灵活运行CFB机组设计思路

5 结语及展望