Originally Detroit Energy, DTE Energy Services has branched out into a national footprint. The Electric and Gas Utilities division produces power; “We are in the Non-Utility Businesses unit,” said Mike Srock, senior technical engineer, DTE Energy Services.
DTE recently purchased its St. Bernard facility, a 14 MW multi-fuel cogeneration plant in Cincinnati, Ohio, that provides electric power and steam for local industrial customers including Cincinnati Biofuels, J.M. Smucker Co., Procter & Gamble, and St. Bernard Soap Company.
[sidebar id =1]Srock co-presented with Alexander Mericle, technical analyst, DTE Energy Services, in the Power & Energy Forum at Automation Fair this week in Atlanta.
The plant was built as part of the St. Bernard Soap Company, which dates back to 1886. It included one steam turbine, one heat recovery steam generator (HRSG), two package boilers, one coal boiler converted to natural gas, wastewater treatment including reverse osmosis (RO) and condensate units, and “state of the art control systems – for the 1980s,” Srock said.
Old dog gets new tricks
Two of the boilers needed new controls, and the control system running the turbines had no support. “The 1980s DCS for plant-wide control and monitoring had everything piped to it with little adapters and devices,” Srock said. “There were walls of PLC-5s at their end of life—you could still get parts, but they were very expensive, so it was very expensive to keep the plant running.”
The plant had two control rooms because at some point, “They built a new one and couldn’t move everything into it, so operators had to keep running back and forth,” Srock said. “The newer one, with the DCS, looked cool but was hard to support.” One reverse osmosis (RO) unit had the DCS company’s PLC, the other an Allen-Bradley touchscreen and Flex I/O from Rockwell Automation.
Help came in the form of a modern distributed control system. “We chose Rockwell Automation PlantPAx because of all the platforms available to us, Rockwell Automation products have historically been very reliable and cost-competitive,” said Srock. “The support is world-class, and parts availability has not been a problem.”
The solution included:
- All new Allen-Bradley ControlLogix controllers for balance-of-plant, wastewater treatment, turbine and boilers
- Local HMI for RO and condensate systems, as well as the two package boilers
- An updated SCADA system using Rockwell Automation PlantPAx DCS
- FactoryTalk Historian
- ThinManager thin clients for reduced cost and downtime
“All these separate control systems were merged and standardized on a platform we use in other plants,” said Mericle. The balance-of-plant wall of PLC-5s was replaced by two redundant ControlLogix controllers, with redundant switches for decreased downtime.
Local HMIs were installed for the two boilers and two RO systems, “all with a common look and feel so wherever the operators go, they’re familiar with it,” Mericle said. “We keep the screens in familiar colors so operations can pick up changes the same way that they’re used to.”
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“We also have software redundancy with the virtual infrastructure,” Mericle said. “We save snapshots for backup on FactoryTalk servers with firewalls.” At one point, a power failure knocked out the PlantPAx HMIs on four ThinManager 9 devices. “We had them all replaced in five minutes, and they came right back up.”
Finally, they added an engineering workstation (EWS) to the original control room. “If we lose the server, the EWS can run the plant,” Mericle said. “We put it in the old control room so people don’t play with it.”
Successful rescue raises reliability, reduces costs
High points of the results include tighter integration using Rockwell Automation common platforms, improved supportability, cost reduction, “increased technician availability, and increased parts obtainability,” Mericle said. “The old system required specialists that we don’t have in the area. There’s just five of us and with Rockwell Automation, we can get support.”
The historical database allows trending, custom reporting and plant efficiency analysis. “FactoryTalk VantagePoint does historical trending, so if there’s an issue, we can go back a week, a month or a year ago, and see what happened and what was going on at the time,” Mericle said.
In the future, “We’re looking at adding AssetCentre for plant-wide use so we can know what’s nearing end-of-life and can focus on that,” Mericle said. Down the road, DTE plans to use big data to better understand asset performance company-wide. “Speaking of big data, we’re using FactoryTalk VantagePoint to knock it out of the park,” Mericle said. “We’re able to produce great graphics with rapid development and easy deployment.”
Due in part to this experience, “DTE is standardizing on PlantPAx due to its many integration and implementation benefits,” Mericle said. Support is readily available, downtime is reduced, revenue is increased, and the system supports rapid development of dashboards, trends and reports using FactoryTalk Historian and FactoryTalk VantagePoint. He added, “We plan to use VantagePoint v7 for mobile deployment.”
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