Study On Control System Of Kiln Outlet Production Line In Cement Industry

Along with the increase of production scale of cement plants all over the world, the increasingly complexity of production technique, and the significantly improvement of product quality, the cement production have higher requests for the industrial control system, and traditional control system DCS could not adapt the modernized control requests any more. Under such situation, the system which is described in this paper selects Siemens's S7-400 series PLC and SIMATIC PCS7 which is integrated with CEMAT software package.The content of this paper is the study on PCS7 control system which based on the kiln outlet technique. Specifically, the content of this paper includes the analysis and realization of network architecture, the methods of hardware configuration, network configuration, CFC configuration and the WinCC picture configuration and the control methods which base on technology. Specifically, detailed analysis is as follows:1. The paper studies on the network architecture of PCS7 control system which can be divided into three layers:field devices layer, process control layer and operation and management layer. The number of I/O points of the entire project are more than 10,000, and the switch points accont for 85% of the total. Therefore, in the hardware configuration, this system selectes S7-400 series PLC which is the most high-end product of siemens in the hardware configuration process. As a result, S7-400 not only satisfied the control needs of large-scale production, but also displayed it's superiority fully in the control of switch I/Os. In the network configuration, this system selectes the way of integrating industrial ethernet and Profibus-DP to realize the communication from operation management layer to field devices layer.2. The paper studies on the control methods which based on the kiln outlet technique. According to the technique, the control methods can be divided into control methods which based on burning technique and control methods which based on cooling technique. The design of control methods is the focal point in the study of PCS7, because it is the ideological basis of CFC configuration. The control ideas of entire production line and the set of key technological parameters' values are realized through the CFC configuration.3. The paper studies on the reasonable values, control methods and detailed control methods of key technological parameters, such as the volume of first air, negative pressure in kiln outlet end, calcined temperature in the kiln, temperature of the second air, clinker which left from cooler and waste gas which enters the dust collecter.Specifically, the control of negative pressure is realized through the adjustment of the speed of exhaust blower and the opening degree of corresponding valves in order to guarantee its value is in the requirement range; The control of secondary-air's temperature is mainly realized through the adjustment of cooler's speed, according to the experience and the analysis to data, the system adopts decentralized control mode to control the cooler's speed in order to guarantee the material on the cooler can absorb even heat, and obtains the suitable temperature of secondary winds. Moreover, this paper studies the control methods of first-wind's volume, the burning temperature in the kiln and the temperature of waste gas to guarantees the steady running of production line steady operation.