Rotary-kiln pelletizing technology is a kind of pellet process which makes use of chain grate machine dry and preheat raw pellet, rotary kiln consolidates and burns pellet in rotary kiln and uses annular cooling machine to cool finished pellet. Pallet produced by this technology is a high-quality blast furnace feed. It has such commercialization advantages as high-grade iron content, good metallurgy capability and being suitable for longtime storage and long-distance transportation. And if used together with sinter, it can effectively decrease coke rate and promote furnace productivity. Its process is advanced and the secondary energy utilization is full and it is environmentally clean. The pallet quality is high and energy consumption is low, and it has good economic and environmental benefits. While the shaft furnace palletizing technology is difficult to be used for large-scale production, because of the the non-uniforminity of pellet quality and poor adaptability to raw materials.
According to the characteristics and the status quo of China's iron and steel and mining enterprises, small and medium-sized chain grate machine - rotary kiln production line teams get rapid development because it’s advanced and practical in techque, low in investment and it can be built in a very short time and quickly put into production and the benefits are good.
Aiming at improveing product quality and reducing costs, we fully absorb the same type of domestic pellet plant construction experience and advanced technology from abroad, so that the main technical and economic indicators have reached domestic advanced level. All equipment in the main production line adopt PLC system to realize centralized and interconnected control and industrial television for monitoring will be set in key production posts to reach domestic advanced automaticity.
Programmable controller and distributed control system are the main products applied in current automatic control of industrial production. We choose the PLC system of Siemens to control the entire rotary kiln. Through realizing a series of functions such as data collection, screen monitoring, remote automatic control and records of historical trends etc, promote labor productivity of the entire rotary kiln system and decrease workers’ labor intensity to ensure production activity running safely and stably.
This automatic control system program is designed and completed based on principles of economy and application, safety and reliability as well as by gathering our company’s experience of many years on maintenance and development of chain grate rotary kiln automatic control system. The main body adopts EIC control thought, that is, the thought of combining electric, instrument and computers. This reduces intermediate links and realizes integrated control to instrument, electric and automatic control system.
Our company conducts integrated design for aspects as follows:
1.Chain grate rotary kiln system, PLC system design, installation, commissioning.
2.Design, installation and commissioning of PLC power supply system.
3.Automatic control system is basic automation including PLC control devices and HMI supervisory control system etc.
4.Design, installation and commissioning of thermal instrumentation system.
5.Design, installation and commissioning of low-voltage power distribution system.
The main control functions
According to requirements of chain grate rotary kiln process to automatic control system, it is applicable to use PLC and human-machine interface to realize functions such as electrical automatic control, data processing and data transmission, equipment status monitoring, and parameter giving etc., and the electrical, the instrumentation and the PLC system together constitute an integrated system. The electrical carries out sequential control to process and production equipment by receiving various information transmitted from computers or synthesized instrumentation devices; during the course of automatic control, transmit status information of certain process and production equipment to the actuating mechanism; display detection contents, show in real time the process flow information in the form of simulation system on the screen, namely, output digital information, visual information and sound information and at the same time record and preserve them. Program control of system equipment start and stop; interlock control between equipments; adjust and revise given parameters according to production practice so as to realize online control to the whole production line.