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March 2013www. .com

SPECIAL REPORT

Coke is one of the base materials for integrated steel mill produc-tion. Coke quality and properties

affect the blast-furnace operation and, as a result, have a direct impact on plant performance.

The control characteristics of coke plants combine process control (battery systems) with machine interlocking co-ordination (pusher machines, coal charging, transfer cars, quench cars) in a distributed automation and supervision architecture.

Coke operations also require a high degree of redundancy, allowing critical operations to be performed even when other systems fail.

Modern coke systems, combined with supervision and control systems, manage multiple technologies working together. Such technologies include networks, wireless systems, cameras, motor control, and positioning and anti-collision systems, which result in more complex operations.

The plant supervision and automation system is an operator graphical interface/human-machine interface (HMI) that allows production and maintenance personnel to operate and oversee coke operations and potential issues including:

• system overview and parameters;

• real-time information processing;

• process trends;

• automatic and manual operation of coke machines;

• alarms and fault detection;

• programmable logic controller (PLC), drives and network status;

• process and production tuning; and

• maintenance and troubleshooting.

THE CHALLENGEA major steel producer needed a new control system for its coke plant with a supervisory system that could manage a complex production environment. The new system was required to run in an environment consisting of multiple electrical components and machines separated by great distances.

Adding to the complexity, there were multiple communication platforms that needed to be tied into the supervisory system. Each machine (coal charger, pusher, quench car, etc.) had to communi-cate globally, as well as maintain full standalone machine functionality in the event of a network communication failure.

Ideally, the customer was seeking a platform that would enable operators to support each other by viewing each other’s screens, assisting in new operator training and other collaborative activities.

Global communication was also important to the customer’s maintenance processes and functions. Through a new control system, downtime would be minimised due to the ability to evaluate problems from a distance, thereby eliminating the loss of time accrued by having to travel to the site to troubleshoot.

The specified system originally required two separate communication networks and associated screen development for local and global systems. This would require extensive mapping and hardware, and two different HMI hardware platforms. For each modification to a given machine screen, all other machines would have to be individually changed.

After the realisation that the initial

specification would not meet the user requirements, a new automation/supervision solution was selected and delivered by Integrated Mill Systems (IMS), an engineering organisation with extensive experience in the metals industry.

The solution IMS suggested was based on the Schneider Electric Viejo Citect SCADA system providing a scalable, ‘view anywhere’ supervisory control and maintenance system. The IMS Viejo Citect system would eliminate the drawbacks and exceed the specification requirements. This supervisory system was also able to handle both an application needing high redundancy capacity and the client servers’ distributed architecture with no perfor-mance disturbance.

The supervision/automation system was able to achieve a unified feel that simplified navigation using touch screens. A consistent operating scheme reduced errors and enabled easy adaption and usability for new users. Because the development process was the most critical, engineering submittals designed to assist the customer in developing the concept into a working operating system were included. This methodology reduced start-up processes and accelerated the cus-tomer’s return on investment (ROI).

RESULTSIn order to meet the supervisory system challenges outlined by the user, IMS presented a superior alternative to the initial specification, which required supplying a specific vendor supervisory/HMI package. This was important as the IMS and Schneider Electric solution could meet the current process requirements, as well as provide a level of flexibility and a path for future development. The customer’s input was vital to validate the IMS and Schneider supervisory system solution with respect to the specification requirements.

The system design and staging was done at the IMS facility to reduce start-up time and eliminate any potential errors, resulting in a faster ROI.

This project has led to an advanced supervisory system, which reduced development and start-up time. It also created powerful templates that can be applied in any large operation (independ-ent of the process); a platform that is scalable to customer needs without costly redesign and extensive programming; and a faster review cycle with the customer that resulted in an accelerated installation time.

The nature of this scalability can be applied not only to this specific coke plant, but also to many other processing systems.

The perfect plantSchneider Electric describes how its plant supervision and automation system has been adapted to meet a customer’s needs

The IMS engineering lab showing Citect systems being tested

HMI shots showing various plant elements

“Global communi-cation was also important to the customer’s maintenance processes and functions”

Written by Fabio Mielli and Nicholas Panno Jr of Schneider Electric and Jim Zelazny and Marius Juodisius of Integrated Mill Systems

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