Formosa Plastics established an electronic group in 1985 and cooperated with Fuji Electric of Japan on the design and manufacture of medium and large-scale decentralized control systems (DCS). At present, Formosa Plastics DCS (Fuji DCS) is widely used in steel, chemical, and paper industries. , schools, hospitals, cogeneration, power plants and other processes. Fuji Electric released the DCS system in October 1975 and is one of the first manufacturers to develop a DCS system in the world. The AX-2000 Distributed Control System is Fujifilm's fifth generation product system. It is an open new generation integrated control system. The intelligent and reliable Process I/O unit is also used by Yokogawa's CS3000 system. AX-2000 system has good control performance, real-time and flexible communication capabilities, intuitive and clear man-machine interface, the system is easy to expand, access to higher user evaluation.
Qinhuangdao Asano Cement Co., Ltd. is composed of Hebei Provincial Construction Investment Corporation, Funing Public Asset Management Corporation, Qinhuangdao Port Group Co., Ltd., Pacific Cement Co., Ltd., Marubeni Corporation, and Marubeni (China) Co., Ltd. Modern cement production company built. It owns a NSP production line with a daily output of 4,000 tons of cement clinker, and produces 1.38 million tons of high-grade cement annually. The company adopts a dry process production process with a five-stage suspension preheater (DD furnace) with advanced international technology in the 1990s. The original fuel and raw materials were homogenized and the host equipment was imported from abroad. All production lines are controlled by the central control room through the Fuji IX-2000 DCS system. Cement quality (acquired ISO-9002 certification), energy saving and consumption reduction, and smoke and dust removal indicators have reached the international advanced level.
1. Cement Production Overview
The process of cement production can usually be summarized as “two-burning and one-burningâ€. That is, the raw materials are ground into raw materials, then calcined into mature materials, and then the clinker is ground into cement.
Limestone, sandstone, steel slag, and fly ash are homogenized and then mixed into a raw material powder through a constant proportioning system. The transfer system transfers the raw material powder to a pulverizer for raw material preparation, and prepares a good raw material into a raw material warehouse. The raw material in the raw material storage is sent to a five-stage suspension preheater through a quantitative feeder and preheated into the rotary kiln system for calcination of the mature material. The calcined clinker is cooled and broken into a clinker silo. According to the different requirements of cement varieties, appropriate amount of gypsum and mixed materials are mixed in the clinker, and after high-precision weighing scales are dosed into cement grinding equipment, cements meeting the requirements of good quality are manufactured.
Figure 1 Flow chart of cement production process
2nd, control system introduction
The cement production line DCS control system of Asan Cement Co., Ltd. of Qinhuangdao City has a total of 1050 points. A total of 4 pairs of ICS-2000 control stations (redundant) are used to control the site; 2 sets of IOS-PC2000 are used to operate and control the system; 1 pair of IDS-PC2000 (redundant) is used to Data is stored and organized, and IES-PC2000 programs and maintains the system.
Figure 2 Schematic diagram of the control system
3 control system functions
3.1 Monitoring and Data Acquisition Functions (SCADA Functions)
The DCS control system collects all real-time data and parameters (such as temperature, kiln rotation speed, kiln feed, raw mix ratio, fan air flow, valve and motor running status, etc.), and displays on the upper computer monitoring screen. The monitoring screen fully and intuitively reflects the entire process of cement production process control and can monitor the operating status of the entire system in real time. The switching between system monitoring screens is simple and convenient, and the interface is friendly. The system processes and processes the collected real-time data through the application program, realizing online real-time control and production management. Reach SCADA functionality and handle alarms in a timely manner.
3.2 parameter setting and modification function
Various process parameters provided by the craftsman are stored in the computer. The operator can set according to the production process requirements, including temperature, batching, feeding amount and PID adjustment parameters, etc., and can modify various setting parameters online. With anti-saturation, integral separation, manual-automatic switching without interference, parameters at any time to modify and other functions.
3.3 System Report and Alarm Processing Function
Operators can query real-time data, historical data, and equipment operating status through real-time trend graphs, historical trend graphs, and reports. This facilitates analysis of faults or optimization of process parameter settings. When the process parameters (including the switch quantity and analog quantity) or the equipment in the controlled object are abnormal, the system will alarm through the screen and sound, and also record the time when the fault occurs in the alarm graph.
3.4 Security Functions The system has a security protection function. Operators and administrators can perform system operations based on their respective privileges.
3.5 Online Flexibility and Extensibility The hardware and software of the control system are standardized, modular, and open design. The modular structure provides flexible screen display and expandability.
4 Conclusion
The NSP production line of 4,000 tons of cement clinker produced by Asan Cement Co., Ltd. of Qinhuangdao City will annually produce 1.38 million tons of high-grade cement. The quality of cement (acquired ISO-9002 certification), energy conservation, consumption reduction and smoke and dust removal indicators have all reached the international advanced level.
The entire Fuji IX-2000 DCS distributed control system has been operating normally since 1997. In use, it fully embodies the characteristics of advanced technology, reliable performance and stable operation, and has been widely praised by users.