CFB机组燃烧控制系统模型分析及优化研究

发布时间：2019-01-27 10:26

【摘要】：循环流化床锅炉作为一种新型洁净煤燃烧技术,已经在我国各容量等级的电厂中得到应用。这种技术凭借燃烧劣质煤方面得天独厚的的优势在我国电力行业中所占的比重越来越大。但是自动控制系统投入率较低的问题也随之而来。这主要有两方面原因:一方面是因为CFB锅炉内部燃烧机理亟待研究,另一方面是成熟煤粉炉的自动控制系统不能完全适合于CFB锅炉。随着循环流化床锅炉大型化的发展趋势,对燃烧系统内部机理的研究也逐渐深入。本文基于CFB锅炉稀、密相区能量平衡以及质量平衡方程,根据现场数据辨识得到床温和主汽压的数学模型,为后续的研究奠定了基础。首先,本文针对床温和主汽压之间的耦合情况,使用了前馈补偿法和串联补偿法两种解耦算法实现解耦。通过解耦得到了给煤量控制床温、一次风量控制主汽压的单变量控制系统。然后,本文针对建立的模型进行参数辨识,最终获得了给煤量扰动下床温的数学模型。分别采用PID控制、模糊控制、模糊自适应PID控制对系统进行了仿真。通过对仿真曲线的对比分析,得出智能算法比传统算法在控制品质上效果更好。最后,本文针对某电厂CFB锅炉燃烧优化的实际课题,分别对床温控制系统、给煤量控制系统、石灰石量控制系统进行了优化设计,使控制系统有完全DCS模式和优化控制模式两种控制方式。实验结果表明:优化后系统的控制品质有了很大的提高,且可以与原DCS系统完成相互跟踪、无扰切换。
[Abstract]:As a new clean coal combustion technology, circulating fluidized bed boiler (CFB) has been applied in power plants with different capacity levels in China. With the advantage of burning inferior coal, this technology is more and more important in China's electric power industry. But the problem of low input rate of automatic control system also follows. There are two main reasons for this: on the one hand, the internal combustion mechanism of CFB boiler needs to be studied urgently; on the other hand, the automatic control system of mature pulverized coal boiler is not fully suitable for CFB boiler. With the development of circulating fluidized bed boiler (CFB), the internal mechanism of combustion system has been studied deeply. Based on the energy balance and mass balance equations in the dilute, dense phase region of CFB boiler, the mathematical model of bed temperature and main steam pressure is obtained according to the field data, which lays a foundation for further research. Firstly, for the coupling between the bed and the main steam pressure, two decoupling algorithms, the feedforward compensation method and the series compensation method, are used to realize the decoupling. A single variable control system is obtained by decoupling the bed temperature and the primary air volume to control the main steam pressure. Then, the parameter identification of the model is carried out, and the mathematical model of bed temperature under disturbance of coal quantity is obtained. PID control and fuzzy adaptive PID control are used to simulate the system. Through the comparison and analysis of the simulation curve, it is concluded that the intelligent algorithm is more effective than the traditional algorithm in the control quality. Finally, aiming at the practical problem of combustion optimization of CFB boiler in a power plant, the paper designs the bed temperature control system, coal feed control system and limestone quantity control system respectively. The control system has two control modes: complete DCS mode and optimal control mode. The experimental results show that the control quality of the optimized system has been greatly improved, and the system can track each other with the original DCS system without disturbance switching.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM621.2;TP273

【参考文献】