Emerson Process Management has modernized steam turbine controls at the GIM Channelview Cogeneration LLC plant with itsOvation™ expert control system
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Emerson’s Ovation™ system contributes to additional 8 megawatts of generation plus annual savings of $25,000 – $40,000 in maintenance and fuel costs
PITTSBURGH (July 19, 2011) — Emerson Process Management has modernized steam turbine controls at the GIM Channelview Cogeneration LLC plant with its Ovation™ expert control system. Benefits to the plant located near Houston have included greater operational efficiency and reduced maintenance costs.
GIM Channelview is an 830-MW, combined-cycle (4x4x1) cogeneration plant that provides electricity and steam to Equistar Chemical’s Channelview Complex, with surplus electricity sold for use by Texas consumers. The plant, which began commercial operation 10 years ago, utilizes four 170-MW Siemens-Westinghouse 501F natural gas-fired combustion turbines, four heat recovery steam generators (HRSGs) and one Alstom COMAX steam turbine.
For years, GIM Channelview had experienced significant functionality issues and high service costs associated with the three controllers originally installed on the Alstom COMAX steam turbine. In November 2010, the GIM Channelview plant replaced the existing system with Emerson’s Ovation control system. Ovation technology was already controlling balance-of-plant (BOP) equipment and processes at the facility, including the four HRSGs, condensate system, natural gas system and switchyard, as well as interfacing to the four combustion turbines.
Upgrading steam turbine controls to the Ovation system has improved the plant’s operational efficiency. Unlike the previous system, the Ovation control scheme uses a temperature and pressure differential bandwidth to ensure that the admission steam valve opens properly in order to release low-pressure steam back to the turbine for improved efficiency. This feature alone saves GIM Channelview $5,000 –$10,000 annually in fuel costs.
The new Ovation control philosophy also enables accurate tuning of the initial pressure control loop, high-pressure upstream blade and duct burners. Resulting performance improvements contribute to the plant’s ability to generate an additional 8MW of power.
The control modernization also provides GIM Channelview with numerous operational and maintenance savings. For example, the Ovation system provides automated steam turbine startup and shutdown sequencing. Prior to the upgrade, plant personnel had to perform these tasks manually. Ovation’s automated startup and shutdown sequencing provides tighter monitoring and control of temperature and speed, thereby greatly reducing the risk of equipment damage.
Furthermore, with the existing proprietary control system, all maintenance, service or other modifications had to be performed by the OEM, which was both costly and time-consuming. In contrast, Ovation technology is designed to allow users to easily perform diagnostics and modify control strategies. Beyond the time and inconvenience of relying on the OEM, GIM Channelview expects to save roughly $20,000 – $30,000 each year in steam turbine maintenance and service costs.
“Our confidence in efficient plant operation has increased significantly since installing Ovation for direct control of our steam turbine processes,” said Doug Marcontell, maintenance manager, Channelview Cogeneration plant. “Now, our technicians are armed with practical tools for in-house maintenance and problem solving, allowing them to make immediate changes to the control logic when needed. Beyond saving us tens of thousands of dollars, this capability will help us optimize plant operations across the board.”
Consolidating control systems also moves GIM Channelview closer to a common platform across the entire power block, which is advantageous on several fronts: It reduces the inventory of spare parts that must be kept on site. It streamlines operator training and helps optimize personnel deployment. And it enables plant personnel to operate the entire plant on an integrated system without having to leave the central control room.
The Ovation retrofit project also included eliminating the manual calibration of six proportional control valves, renovating the automatic turning gear to engage automatically on coast down, and streamlining the control schemes for easier troubleshooting.
“Over the years, Emerson has supplied thousands of steam, gas, and hydro turbine control solutions,” said Bob Yeager, president of Emerson Process Management’s Power & Water Solutions.
According to Yeager, the reason for this success is simple: The Ovation system offers features proprietary systems don’t have, such as automated startup and shutdown sequencing, specialty turbine interface cards, built-in security features, and embedded advanced control applications.
“Ovation’s ability to provide precise and reliable control is more important than ever, as utilities look to obtain incremental performance improvements from their existing generating assets,” Yeager continued. “The measurable benefits GIM Channelview is experiencing dramatically demonstrate how Ovation technology can greatly improve plant reliability and efficiency.”
The retrofit was a turnkey project, with Emerson responsible for designing, engineering, manufacturing, testing, training, installing and commissioning the control systems. In all, the integrated Ovation control system now manages more than 3,100 I/O points across the entire plant, and includes nine redundant controllers and nine engineering and operator workstations communicating over a Fast Ethernet network architecture.
Timing was an important consideration for this project. Because steam flow could not be disrupted to Equistar Chemical’s Channelview Complex, installation of the new steam turbine controller had to be coordinated with the upgrade of the existing Ovation BOP control system. Emerson was able to perform the entire system upgrade while keeping three of the four gas-fired combustion turbines operational at all times in order to satisfy GIM’s contractual obligations for steam production.