The Latest Development Trend of Automation in Cement Industry

Release time:

Jan 11,2012

1 information technology to promote enterprises to achieve automation control to information technology to transform the cement industry, to promote automation, automation and then promote energy saving, environmental protection, safety, high efficiency of the four goals, has become the consensus of the industry. In today's automation field, from the process site layer to the factory (group) management layer can basically realize the smooth and seamless flow of information through Ethernet. The so-called "modern integrated production process" combines information technology, network technology and modern new processes and is applied to all stages of the enterprise product life cycle. Through the seamless integration of information, process optimization and resource optimization, logistics and information can be realized.

1 information technology to promote enterprise automation control

It has become the consensus of the industry to transform the cement industry with information technology, to promote automation, and to promote the realization of the four goals of energy saving, environmental protection, safety and high efficiency. In today's automation field, from the process site layer to the factory (group) management layer can basically realize the smooth and seamless flow of information through Ethernet. The so-called "modern integrated production process" combines information technology, network technology and modern new processes, and is applied to all stages of the product life cycle of the enterprise. Through the seamless integration of information, process optimization and resource optimization, the integration of logistics, information flow and value flow is realized to shorten the development cycle (T), improve quality (Q), reduce cost (C), improve service (S) and improve environment (E) of enterprises, so as to improve the adaptability and competitiveness of enterprises in the market. A series of management software, such as ERP, MRP, MIS, PES, etc, and more and more show its huge economic benefits.

A domestic cement group has added a manufacturing execution system (MES) layer at the top of the field level and process control level (PCS) when configuring the automatic control system for the newly-built cement production line, and is planning and operating ERP, I .e. enterprise resource planning and management, it includes production management system, quality control system, procurement management system, warehouse management system, sales subsystem, equipment management system, financial management system, office automation management system and integrated management subsystem. Under the situation of oversupply and fierce competition in the cement market, due to the initial realization of MES operation of the group, the control and execution of group management have been significantly improved. The refined operation mode has controlled the logistics cost and raw material cost, realized the substantial increase in comprehensive benefits, and the net profit increased by 12.76 over the same period last year. The author thinks that the MES operation of the group is still in its infancy, and further development is needed to unify the production scheduling and the decision-making of the enterprise leaders into a real enterprise management level (ERP).

Nowadays, the combination of computer technology, network technology and advanced control technology is no longer in the theoretical and experimental stage, such as model prediction, neurons and neural networks, fuzzy control, multivariable control. Advanced control algorithms such as adaptive and self-seeking have been put into practice and used in DCS, PLC and other controllers, and this trend is accelerating. Fuzzy control, multivariable control and expert systems for kilns and mills in the cement industry have been used as early as the last century, but most of these are developed by cement equipment suppliers, such as FLS, KHD, etc., which provide only independent software and have almost no connection with the system. However, now the suppliers of control systems have applied advanced control algorithms to DCS, PLC and other controllers. For example, CEMAT integrated standard software specially developed by Siemens Company for cement industry has the function block of process control optimization in cement plants, and also includes the load optimization control of kiln calcination and grinding. This software package is integrated into Siemens Company's process control system PCS7; ABB's Opti-mizeIT optimization experts are integrated into the IndustryIT, which controls the cement production process and implements optimal decision management by integrating a large number of proven advanced control technologies and a wide knowledge base of experts, such as fuzzy logic, control models, neurons and fuzzy control.

Another hot spot in the combination of IT technology and automation is the penetration control system such as public database, local area network, Internet and wireless technology, which makes the control system flat and realizes cross-platform and cross-regional control.

2 Complementarity and penetration of automation technology

DCS, PLC and IPC are the three pillars in the field of automatic control. They compete fiercely, but they learn from each other and penetrate and merge with each other, thus forming a PLC/DCS hybrid system HCS with hybrid control strategy, which is called PAC by a consulting group. As a typical process industry, the cement industry determines the dominant position of its switching logic control. At the same time, the processing of analog quantity is mostly simple display and given, and the control loop is basically not complicated single-loop adjustment. These characteristics are suitable for HCS applications. At present, Siemens, Schneider, Rockwell and other companies with PLC as the dominant position in the market have launched PLC/DCS hybrid system HCS with hybrid control strategy, which has been promoted as the leading product in the cement industry and achieved good results.

The main features of the hybrid system HCS are: to build a common, integrated development environment, providing a common development platform, common tags and a single database to meet the needs of multi-domain automation system design and integration; at the same time, it uses a freely combinable modular hardware architecture to reduce the cost of system upgrades. It supports fieldbus international standards such as IEC61158 to realize a highly decentralized automation environment, and also supports the de facto industrial Ethernet standard, which can be easily integrated with ERP, MIS and MES at a higher level.

3 automation system pay more attention to function and information security

Safety in production has attracted more and more attention. Human life is above all else. It has become an important indicator to measure modern industry. It is more important for our country where safety accidents occur frequently. The main safety considerations of the automation control system are: electrical safety, explosion-proof safety, information safety and functional safety.

Information security refers to the security of systems such as information leakage and hacker intrusion; functional security refers to the possible danger caused by the failure of the security functions performed by the control system. At present, the international standards that have been issued successively include IEC61508-functional safety standards for electrical/electronic/programmable electronic safety-related systems, IEC61511 functional safety standards for safety instrumented systems in the process industry. Generally, the overall safety level SIL is used to assess the risk level. There are 4 levels in total. The higher the safety level SIL, the lower the risk.

The cement industry has mostly adopted the new cement dry process, which is a continuous process and has realized the sequence and chain control of the computer system. The author thinks that the new dry process has a high safety level. To further improve the overall safety level, the fault diagnosis link must be strengthened. The man-machine operation interface should facilitate fault monitoring. For production lines with larger production scale, such as production lines with a daily output of 10,000 tons of clinker, redundancy should be improved. In addition, information security must also be highly concerned. The explosion-proof safety level of coal mill workshops should be specially enhanced. For enterprises setting up low-temperature waste heat power generation, the overall safety level SIL should be higher than that of ordinary enterprises.

In the field of automation have introduced the corresponding standard products, such as the Siemens fault-safe fault-tolerant S7F/FH system, Rockwell GruardPLC, etc., some companies are equipped with dedicated security modules and the corresponding configuration software, and by passive maintenance, diagnosis development to preventive security measures, which also introduced a number of security protocols, such as PROFIsafe, CIPsafety and so on.

4. Development of control systems from centralization to decentralization

Intelligent distributed I/O is the formation of a certain part of I/O into an autonomous node with its own processor to independently complete the control of a certain part. Because it is combined in a framework, it can be installed directly on the site, even where the space is very limited, but it can be linked to the central computer at the same time, thus simplifying the control system from the traditional three-layer structure to the two-layer structure. Many famous PLC manufacturers have introduced distributed I/O, such as Siemens's ET200 series, Rockwell's FlexAr-morI/O,Wago's WAGO-SPEEDWAY767 and other high-speed intelligent I/O. Intelligent distributed I/O will make the system configuration of the cement production line more flat, the original set of remote I/O occasions, such as mines, pre-batching stations, etc. can be replaced by intelligent distributed I/O, in order to save the I/O installation cable and the overall cost of the control system.

5 Wireless communication technology to further penetrate the field of control

Wireless communication technology, as a supplement to wired control systems, is in the ascendant for industrial automation systems, is also a new growth point of industrial automation products, running in the 2.4GHz1SM band frequency hopping spread spectrum (FHSS) wireless transmission technology has excellent anti-interference and high reliability, wireless local area network and wireless mesh network to expand the coverage of wireless transmission. The data security of wireless communication is of concern to people, but a series of measures such as adding a secure password and an encrypted password can be taken to ensure the secure transmission of data. It is reported that the HART Foundation will launch a new protocol for HART wireless communications in the near future.

In the cement industry, some large groups have adopted wireless technology for local auxiliary processes. For example, Jidong Cement Group has adopted wireless control in circulating water pumping stations, and some cement plants in Zhejiang have adopted wireless control for loading and unloading bulk cement ships. Considering that some cement plants occupy a large physical space, some process measurement positions are difficult to install, and some process measurement points have very harsh environment, and the cost of installing devices with traditional hard wires is too high, if the switch to wireless communication can save energy, reduce wiring and maintenance costs.

6 man-machine interface more humane

The man-machine interface has been fully serialized, including handheld, panel, desktop and PC. In the future, the man-machine interface is not only limited to SCADA, programming, monitoring and diagnosis. In the field of industrial automation, the man-machine interface can provide more and more information for operators and managers. The powerful modular software and multi-client/server structure make the man-machine interface become a unified software platform for real-time production information and business vertical integration, and it is also a medium connected to the outside world. Through the drive or OPC to drive a variety of I/O modules, in short, the man-machine interface has evolved into a complete system.

The operation of MES of a cement group, the control of group management mainly depends on a variety of man-machine interfaces, through OPC to achieve the exchange of information between the various cement production lines within the group, but also to achieve the main control system and the interconnection of the sub-control system, such as raw material quality control system.

7 inverter performance is more extended

The application field of frequency converter has expanded from conventional fans, pumps, etc. to conveying and feeding machinery, etc., and has become more and more widely used in the industry. Therefore, its functions have been further improved and diversified. On the one hand, it is fully digital, fully functional, adaptive and tuning technology capable of compensating load changes, especially distributed high-end frequency converter with communication, networking functions and integrated PLC. On the other hand is a simple or dedicated inverter, as well as mechatronics inverter. In terms of control technology, DTC direct torque control and sensorless vector control are the development directions. At present, the speed response is about 2ms, and the current response can reach 0.1~0.5ms. The development trend of speed regulation is to improve the speed control accuracy, generally in the closed loop, corresponding to the full range, speed ratio of 1:100 or higher, the speed control accuracy of up to 0.05. In addition, the performance of the inverter is also enhanced in terms of overload capacity at low speed, stable, four-quadrant operation capacity and load balancing of multiple motors driven by one machine. In order to save energy and reduce consumption in cement industry, fans, pumps, conveying equipment, feeding machinery and so on have been widely used. How to withstand large overload torque at low speed and improve the cost performance of medium voltage inverter is a subject for manufacturers. The introduction of Robinkon medium voltage inverter as the preferred scheme of medium voltage inverter by Siemens company will help to improve the cost performance.

In addition to the above fields, in the field of automation, there is the protrusion of radio frequency identification technology (RFID), which promotes the rapid development of machine vision and its systems; and the vision system is connected to the motion control system, which is more highly intelligent, which is extremely beneficial for the manufacturing industry with hundreds of drives to improve production efficiency and reduce operating costs. Another hot spot is the breakthrough development of industrial Ethernet, which makes the three-layer network of industrial control more seamless and can communicate with the IT world. The development of automation technology will enable us to achieve the four goals of energy saving, environmental protection, safety and efficiency as soon as possible.