Research And Implementation Of Monitoring And Controlling System For CFBB Multi-function Test-bed

As a new type of solid fuel combustion technology, circulating fluidized bed boiler (CFBB) is highly efficient, low-pollution, fuel adaptability, good load regulation performance. It received a wide attention and became a major coal burning technology, all around the world. The rapid development of Commercial circulating fluidized bed boiler has put forward higher requirements of its automated operation.In order to enable students to learn more about the process of CFBB and to be familiar with the operation of CFBB, complete a number of boiler-related undergraduate experiments, Ningbo Institute of Technology built a large-scale multifunctional experiment rig with CFBB as the core structure. Addition to being able to meet the needs of undergraduate teaching experiment, this multifunctional experiment rig also provides effective support for the boiler and combustion related research project. Research task of this article is to develop a computer automatic monitoring system for the multifunctional experiment rig, The key points are hardware, software system design and realization of automatic control functions.Multi-function rig automatic monitoring system uses high-performance PLC, industrial control computer (PC) running with SCADA application software, field sensors, transmitters, actuators, etc,together to make a distributed control (DCS) system. This automatic monitoring system can supervise and control the running of the multifunctional experiment rig. When designing the key control loops of the multifunctional experiment rig, this paper analysed several modern PID control arithmetic, and decided fuzzy_PID controller algorithm for the furnace temperature, the furnace negative pressure, working fluid flow, etc control loops.The key points of automatic monitoring system design of the multifunctional experiment rig are the control software design of PLC lower computer and the SCADA application sofeware design of host computer. The lower computer software was designed on the Step 7 software platform,and realized the functions like raw data pre-disposal,control loop controller, the auto-control of hearth temperature, hearth pressure, refrigerant flow rate,etc. The SCADA application software was designed on platform of WinCC,and actualized the functions like system data realtime display, data storage, process interface displaying, equipment soft hand operation, etc. The automatic monitoring system has the characters like friendly operation interface, easy to operating and so on.The multifunctional experiment rig had been run for the experiment course like boiler heat balance, pump arid fan characteristics, characteristics of CFBB and boiler running operations,ect, from November 2008 to July 2009. The running practice showed that the control system can supervise and control the multifunctional experiment rig running stably and safely.