Perhaps no industry represents the spectacular growth of Chinese manufacturing and infrastructure better than the country's steel industry, with the People's Republic of China having grown into the world's leading producer of crude steel.
Along with China, Jinan Iron and Steel Group steadily grew as its country's demand for steel increased. With more than 37 000 employees and US$10 billion in assets, the company's annual steel output now exceeds 3 million metric tons. Jinan Steel is currently one of the leading exporters of medium and thick board and the eleventh largest steel producer in the country.
Like many iron and steel companies, Jinan Steel also produces coke, the coal based fuel needed to fire its plant's blast furnace. Coke represents more than 50% of an integrated steel mill's total energy use, with about a half ton of coke needed to process a ton of iron. Jinan Steel is therefore continually looking for ways to optimise its coke production to both contain its energy costs and increase the amount available for domestic sale and export.
Smooth, reliable operation of the coke oven is essential to cost-effective production of coke. The coke oven provides the oxygen deficient atmosphere and high temperature (1100°C) needed to convert coal to coke. To improve the efficiency of its coke oven - and ensure stable operation - Jinan Steel called on Rockwell Automation for a control system upgrade. The automation specialist recommended a complete automation solution based on Allen-Bradley ControlLogix controllers, running on ControlNet, for the retrofit.
The ControlLogix system is a high-performance, easy-to-use control platform ideally suited to demanding control applications. And it is industrially hardened to particularly withstand the vibrations, electrical noise and thermal extremes inherent to the coking environment. Four ControlLogix stations - one for each subsystem - were installed to control the moving equipment. In addition, a fifth ControlLogix unit was installed as a master control station. It coordinates the other four ControlLogix stations and also provides the PID loop control needed to maintain the precise temperature and interlock control functions within the oven itself.
All control stations within the system are integrated via a ControlNet network. ControlNet provides deterministic, repeatable transfers of all mission critical control data in addition to supporting transfers of non-time-critical data. In addition, ControlNet features high-speed (5M) data throughput, which improves I/O performance and controller-to-controller interlocking, and enables realtime control. RSView, by Rockwell Software, provides the central monitoring for the plant. At the same time, Allen-Bradley PanelView stations provide the local operator interfaces for each subsystem. The rugged, easy-to-use PanelView utilises standard tools, objects, graphics and imported bitmaps to allow operators to quickly understand the status of the application - in realtime.
To ensure a fast and seamless system changeover, Rockwell Automation first tested all logic functions within the new system and then operated it for one month before the switch. On the day of the changeover, the new ControlLogix system was up and running within a half hour. Local service and support by Rockwell Automation distribution partner, Jinan Huazhang Electric, helps ensure that the system continues to operate at peak efficiency.
During the two years since the system was installed, the coke oven has continued to run reliably - unscheduled downtime is a thing of the past. The ControlLogix system continuously provides the precise control needed for this application and withstands the harsh coking environment with very little maintenance. As a result, Jinan Steel has significantly reduced its operating costs.
According to the project engineer, the company is confident it will realise similar results when it calls on Rockwell Automation to retrofit its #6 and #7 coke ovens in the near future. "The excellent quality and high stability of Rockwell Automation's ControlLogix system have convinced us that we have found the right solution for our coke oven retrofits," the project engineer said. "We plan to install the ControlLogix system soon in other coking applications."
For more information contact John Duncan, Rockwell Automation South Africa & Middle East, +27 (0) 11 654 9887, [email protected]
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