- Tata Steel needed to upgrade the control solution on four of its kilns in Shapfell, but the window for replacement per kiln was just 16 hours
- Dual redundant Allen-Bradley ControlLogix PAC
- 5,000+ Allen-Bradley POINT I/O nodes
- FactoryTalk View site edition (SE) SCADA
- FactoryTalk Historian
- FactoryTalk VantagePoint
- Far less risk of failure
- Full off-line virtual testing prior to install
- Off-line virtual training prior to install
- Modern communication network enabling data capabilities in The Connected Enterprise
- Real time visibility of manufacturing/process data
Tata Steel's limestone quarry and lime kilns, located in Cumbria in the UK, have been producing quicklime and limestone products since 1962.
At the plant in Shapfell, the company produces high-performance lime products created to meet the requirements of a wide range of applications.
Lime products include CE-marked fine lime, other size grades and ground limestone in flexible quantities and at short notice.
In a recent audit, Tata Steel realised that the control infrastructure managing four of its Maerz lime kilns was at the end of its lifecycle and was effectively obsolete.
As well as facing potential operational failure risks associated with obsolete hardware, Tata Steel was also seeing increased maintenance costs and diminishing performance levels.
It had a problem with alarming too, not only in terms of the quantity of alarms, but also with regard to how to effectively manage them.
Easier connectivity to the rest of the plant would also be of huge benefit, allowing Tata Steel to exploit the capabilities of future Connected Enterprise opportunities. As a result, the control system had to be replaced as a matter of urgency.
Tata Steel put a tender out for the modernisation project to many of the leading suppliers of automation solutions, including the incumbent supplier.
After a rigorous vetting process, it opted for a Rockwell Automation based solution designed and delivered by InControl Systems Ltd., a company that has been providing turnkey solutions for process control, automation and information systems for over 14 years.
Tata Steel chose InControl’s solution for a number of reasons, one was the cost competitiveness, coupled with greater flexibility and easier connectivity offered by the Rockwell Automation solution, and another was because of InControl’s ability to undertake changeovers in incredibly tight windows of opportunity.
The project entailed the complete replacement of the legacy controllers and SCADA system with a modern solution based on dual redundant Allen-Bradley® ControlLogix® programmable automation controllers (PAC).
These would be working in conjunction with FactoryTalk® View Site Edition (SE) SCADA, FactoryTalk® Historian and FactoryTalk® VantagePoint®; with primary data pathways to over 5,000 Allen-Bradley POINT™ I/O nodes, other plant IT systems and remote support gateways being provided by an EtherNet/IP™ network.
As well as transferring the control solution over to the new platform, the primary challenge faced was the limited timescale in which it could achieve a successful changeover.
This timescale was governed by how long the kilns could be switched off before the refractory lining began to degrade – in this case less than 16 hours.
Any longer and the bill for repair could run into many thousands of pounds.
The alarm system also had to be addressed, with the creation of a solution guided by EEMUA-191 that could prioritise the alarms and then notify the operators in the most effective way.
In addition, the operators needed a way to manage the alarms so that they could be postponed in order to cater for the variations in production ‘foibles’ – due to the variable mechanics of the raw materials – and their subsequent self-remedy.
Prior to the installation of the new contemporary system a fully simulated environment was built and run within the ControlLogix PAC, which mimicked the way the kilns worked, simulating the process conditions off line.
PlantPAx process control system faceplates were also used modified to meet the Tata Steel standards.
“We then gave this to Tata Steel,” explains Jan Hemper, Technical Director at InControl, “to let its engineers run and test the new solution and deliberately create faults to see how it handled the alarms.
Their feedback then allowed us to fine tune and refine the control system before we put it anywhere near the kilns.
“This virtual testing using VMware-compliant Rockwell Automation software allows us to do an incredible amount of off-line testing,” Jan continues, “but using real-life parameters.”
Virtual testing is much easier and a lot faster than on-site testing and delivers greater peace of mind to the customer.
In addition to the refinement, the virtual environment also proved ideal for training, so the engineers at Tata Steel were already up to speed before the hardware was rolled out.
The virtual environment is highly flexible when it comes to managing issues, too.
InControl could simply delete virtual machines, reimport their templates and then reinstall the Allen-Bradley products back on to the server.
To address the alarms, a situational-awareness type approach was deployed, with a solution based around a ‘dark-desk’ philosophy.
To the operators, the control room screens appear subtle and bland but when something goes wrong it really jumps out.
Jan explains: “When there aren’t any alarms, the screens are a symphony of grey. When alarms do appear they will only be apparent in one of four primary colors – blue, yellow, red and green – in fact these are the only colors used in the in the operator works stations .”
The primary remit for the alarm delivery and management system was to follow EEMUA 191 guidelines, a standard for the design and management of alarm systems.
Since it was first published in 1999, EEMUA 191 has become the globally accepted and leading guide to good practice for all aspects of alarm systems.
The kilns have radiation-based level transmitters, which are used to gauge the stone level.
The problem is the stones can back up or bridge and then drop, so the actual level will fluctuate. One alarm that kept appearing with the old system was ‘stone level low’, which triggered every couple of minutes across all four kilns.
“When we were translating the software from the original system we looked at the entire state of the alarms, rationalised them and then classified them based on importance,” Jan explains.
“We utilized the ability of operators to shelve the alarms too, in effect snoozing or hiding them for a while to give engineers the time to fix any issues.”
There are still over 2,800 potential alarms in the system, but the shelving functionality allows the operators to consciously tidy up the alarm screen and prevent the alarm logger being continuously stamped.
Since the installation, the new control solution has been working as designed and has proven to be a more than capable replacement for the older system.
Along with the significantly reduced risk of failures, Tata Steel is also seeing many other benefits of a contemporary control solution.
These include: far more effective data management, thanks to FactoryTalk Historian; the effective collection and collation of real time data, allowing the company to make better informed role-based business decisions; and clearer data presentation and disbursement thanks to FactoryTalk VantagePoint.
The use of an EtherNet/IP communication backbone has also allowed Tata Steel to exploit the power of The Connected Enterprise.
The new control solution not only connects to the site’s ERP system, but also to its quality system, laboratories and its road & rail logistics system.
The use of an EtherNet/IP-based communication protocol also gives InControl the ability to ‘dial in’ to the site to remedy any issues without having to undertake costly engineering visits.
Jan adds: “A lot of people are wary of letting you touch their kilns. If you wreck the refractories, it costs thousands to fix.
We have proved that modern control solutions can be implemented in incredibly short time windows and at a very attractive price point.
We have now modernised four kilns at Shapfell and are eager to let other Maerz kiln operators know that we now have a standard tried-and-tested solution.”
According to Ian Busby, engineering Manager at Tata Steel’s Shapfell plant: “We needed a solution that would offer us good reliability that could help us replace the older system in stages without disrupting the production.
We also went for a system that would be supported by readily available spares and one that could deliver remote support. The Rockwell Automation-based solution ticked all the boxes.
“We are now seeing more real time information,” Ian concludes, “so trending is a lot more straightforward.
The next stage will be to look at increasing efficiencies at the plant, which will be more straightforward thanks to our new data capabilities and the ability to easily add more hardware.”
Allen-Bradley, ControlLogix, FactoryTalk View Site Edition (SE), FactoryTalk Historian, FactoryTalk VantagePoint, LISTEN. THINK. SOLVE., PlantPAx, POINT I/O and Rockwell Automation are trademarks of Rockwell Automation, Inc.
EtherNet/IP is a trademark of ODVA, Inc.
Trademarks not belonging to Rockwell Automation are property of their respective companies.