Research And Application On DCS Of Circulating Fluidized Bed Boiler

Fluidized-bed combustion is one of the best commercial combustion technologies of clean-coal currently, it has safe, efficient and clean characteristic. The circulating fluidized bed boiler (CFBB) is a kind of boiler which using fluidized-bed combustion technology. It has lots of prominent advantages includes wide fuel adaptability, high burning efficiency, low nitrogen oxides emissions, low desulphurization cost, large load regulation proportion and so on. Used in home and abroad widely. Today, governments advocate the energy conservation and emissions reduction vigorously; circulating fluidized bed boiler has wide application prospects. However, it's low that the level of automation of circulating fluidized bed boiler, Automatic control technology for circulating fluidized bed boiler has become the bottleneck of commercial application. This thesis is directed against some key issues about control technology of CFBB, and carried out the research and application of DCS, made beneficial attempt to improve the level of automation of CFBB.The circulating fluidized bed boiler is a complex control object with multiple input and output, time-varying, multi-operating mode, barge lag, nonlinear and multivariate tight coupling. General control strategy is decompose the whole system into several independent control subsystems according to their process characteristics and coupling degree, and then design control strategy for every subsystems respectively. Lag, nonlinear and coupling is most evident in combustion system, which is the difficulty of control system.According to the characteristics and the difficulties, this subject mainly research in two ways. First, after analyzing the characteristics of the control of CFBB, deep research in the decoupling control algorithm and advanced process control system. Specifically, Research of coupling characteristics and methods for reduce and eliminate the coupling. Put forward a kind of indirect fuzzy decoupling coordinated control algorithm. In the design of concrete, Combustion system used this method and achieved good control effect, increased energy conservation and emission reduction effect obviously. Second, analyses the characteristics development trend of current process control system. Selected the DCS which adopt advanced and mature technology and meets the requirements of CFBB. Take DCS as control platform, researched and designed the detailed control strategies. Realize the relevant control loop and operating pictures.Rely on thermoelectric workshop DCS project of Chongqing Nanchuan Xianfeng alumina Co., LTD the phase iii extension project. Use Honeywell Company's PlantScape Vista/HC900 controller, Combined with the control configuration software HC designer, and combined a complete set of distributed control system. With this platform, through the configuration and human-computer interface design, realized the fuzzy decoupling algorithm and the control strategy. And through the debug and optimize, make system operation successfully. Decoupling algorithm and control strategy what has been expounded in the paper will be certain reference for the next similar circulating fluidized bed boiler control system.