The Development And Application Of Coal Transport System

As the development of China's electric power industry grows rapidly, the capacity of coal-burning power plants represents over 70% of the entire power plant capacity. A highly productive, reliable and flexible coal delivery system ensures not only the stability of a power-generating unit, but also the stability of the entire power plant. As the biggest slave system in a power plant heating control system, the controlling requirement for a delivery system becomes more and more strict. Its proper operation directly affects the performance of the main control system. As for the traditional relay control method, field staff needs to inspect, test and maintain equipment under dreadful conditions due to obsolete controlling method which performs with very low effectiveness. Thus, such method has been replaced by PLC-based process control method. Based upon the above considerations, the coal-burning delivery control system was designed and produced.The hardware of the system consists of two parts: PLC controller using Rockwell's three-tier network framework and an object control system with a simulated coal cabin and boiler. The former includes two sets of ControlLogix control systems and one set of CommpactLogix control system. The latter is composed of a conveyor belt driven by a frequency converting speed control system with three PowerFlex 7 frequency converters and motors. The entire system is operated according to the power plant's actual delivery control strategy by using RSLogix5000 to program PLC and frequency converter, Networks software to plan, and RSlink to communicate. FactoryTalk software is used to design monitoring screen and tracks the PLC status in real time, which monitors the delivery status of the three conveyor belts, the temperature in the boiler as well as the actual coal level in the cabin. It also can send warning signals and take necessary actions, such as sequence of stop, if there are any abnormal situations. In addition, in order to most closely simulate the field situations, the system uses PanelView to monitor the field in real time, PanelBuilder software to design the screen so as to display the system's entire current data. The system also has the function to process warning signals.The entire network of the system meets all communication requirements, and can operate properly. Also, monitoring data accords completely with the field situation and the monitoring data is accurate. It is safe to conclude that the model successfully simulated the coal delivery system in power plant.