Design Of The Semi-Dry Type FGD Control System

In this paper, the development and the application of desulfurization technology are introduced, and the technical choice of FGD engineering are studied and put forward. Furthermore, the control methods of FGD system and electrical design are analyzed mainly, and bring forward the electrical design of Semi-Dry type FGD engineering of Linyi Electrical Power Plant. The engineering design of control system is an important part in application of the technology on fossil fuel power plants. The study on automatic control system in the process of FGD, which is urgent an indispensable part in the whole De-SO₂ technology. Under this situation research on engineering design of the control system is raised, including the project design of whole control system, measurement & control of each loop, the function of DCS(Distributed Control System), and selection of CEMS. Those works are listed as follows.1. China is a main country to produce and consume energy in the world. As is schemed, the emission of S0₂ will drop to 22950 thousand tons in our country in 2010, which is 2540 thousand tons than that of 2005. Therefore, it is necessary to deal with the emission of S0₂. In the past years, many efforts have been made to investigate the technology of desulfurization in order to control the pollution of S0₂ in air. And so far 200 kinds of technology to control S0₂ have been developed, of which the technology of FGD has been applied widely in some large electrical power plants of the world.2. According to developing trends of process-control and character of technological procedure in the Semi-Dry type Circulation Fluidized Bed FGD, the centralized control mode of whole system based on DCS is put forward, which is classified by function as DAS (Date Acquisition System),MCS(Modulating Control System) and SCS(Sequence Control System). And the structure of control system is designed by separated layer. 3. The detail function and configuration of every subsystem of DCS and the criterion on field instrument selection, as per the technical code and requirements of power unit running,is illuminated.4. According to the mechanism of the Semi-Dry type Circulation Fluidized Bed FGD and varies factor which influence system efficiency of desulfuration, the control scheme and logic of MCS and SCS are developed.5. Semi-dry FGD sequence control system are designed according to the practical engineering need. We confirmed some basal design scheme consists of control range, control function and control logic etc. The control system are divided 4 levels according to control function and range, namely unit level, function.Above all, the engineering design of the FGD control system is investigated comparatively deeply. Related control systems have been applied in many engineering of De-S0₂ system, our idea and feed back of all works will supply useful references and experiences for future application in power unit.