韶冶热电分厂流化床锅炉控制系统的研究与实现

【作者】 夏志勇；

【导师】 沈德耀； 卢沛光；

【作者基本信息】 中南大学 ， 控制工程， 2004， 硕士

【摘要】 循环流化床技术作为一种清洁燃煤技术,由于其低污染排放、燃料适应性广、燃烧效率高及负荷适应性强等优点,得到了迅猛的发展。从理论和实践出发,对流化床锅炉控制系统的研究成为势在必行的工作。 本论文首先分析了流化床锅炉的生产工艺。从对其工作过程的分析可以得出,流化床锅炉是一个复杂的系统,有多参数、非线性、时变、多变量紧密耦合特点。理想的控制系统应是多回路的控制系统。当系统受到某一扰动时,各个调节量同时协调动作,使所有的被调量都具有一定的精度;但是,这样的调节比较困难。目前工程处理上做了一些假设后,将流化床锅炉设备控制划分为若干个子控制系统。而在若干个子系统中,燃烧控制和汽包水位控制显得的尤为重要。 对于燃烧系统中所涉及到的主汽压和床温这对互相强耦合参数,本论文设计的控制系统采取的原则是控制床温稳定和在此基础上维持主蒸汽压力稳定。因此整个专家控制方案分为负荷粗调和床温细调两个部分。首先按照蒸汽压力大小设定给煤机转速(给煤量)和送风量以便快速跟随压力的大幅度扰动,然后根据床温调节给煤机转速和送风量。炉膛负压调节则采用随调方式。现场运行曲线表明,床温和主汽压得到有效的控制。 对于汽包水位控制,论文先分析了汽包水位的动态特性,阐明了产生虚假水位的原因。由于传统的汽包水位控制方法不能很好的满足更多还原

【Abstract】 Circulating Fluidized Boiler, CFB, is a clear coal technology. In case of its low-pollution, wide fuel adaptability and high combustion efficiency, CFB is widely used. From theory and practice, the study of CFB is a necessary work.This paper analyzes the product process firstly, and draws the conclusion that CFB is a complicated system that has characteristic of multi-parameters, non-linear, time-change and parameter coupling. The ideal control system is mufti-loop. When a parameter of system is pretreated, the other control parameters should work coordinately. However, this control is difficult. At present, some assumptions have been done in the engineering. The control system of CFB includes many son control system. And in these systems, the combustion control system and the liquid location of steam beam control system are important.From analysis of the perform characteristic of combustion system, we conclude that the difficult of combustion system lies in each other’s influence. This paper aims at controlling steady of temperature firstly and maintaining stability of main vapor pressure secondly. Compensatory solve coupling control method is used. And expert judgment is adopted in the system. The fuzzy control is added in the system. And according to the errors of main vapor pressure and change of it, the range of control amount is changed. All these methods improve the system quality and solve the problem of strong coupling. The practical curve shows it’s useful.The reason of deceived liquid location is detected by analyzing thestream beam perform characteristic. The traditional control algorithm isn’t fit for the real working site. Based on the worker’s experience, this paper proposed the method of expert PID expert control. Practical curve show this control algorithm is efficient.At last, the paper introduces the implementation of hardware and software. This work secures the successful control of CFB.更多还原