Preparing for Expected Growth in Nuclear Power Plants

by Jim Cahill

My spy utility, WatchThatPage, alerted me to another good article, this time on the Fisher control valves and regulators area of the Emerson website. The article, Getting ready for the nuclear renaissance, from the April issue of Valve World magazine, features Bill Fitzgerald, director of the Fisher Valves nuclear business unit.

As more and more people around the world climb the economic ladder, the global demand for energy continues to grow. A nuclear power renaissance is underway, according to Bill driven by:

…issues like global warming and a desire for energy independence... It can never be the only solution, but it is a logical part of the solution.

Bill describes his team tracking forty U.S. projects. He estimates two-thirds of these will actually be built. The first ones may come on-line as soon as 2015. Bill describes the large engineering firms as well as the U.S. Nuclear Regulatory Commission (NRC) staffing up anticipating the work required to completely design, build and commission the first wave of these plants over the next seven years. This expected growth is by no means limited to the U.S.

As part of this process, the engineering firms' procurement people need to identify and begin to purchase the long-lead items like reactor vessels, which may take three years from order to delivery. Control valves also fall into this long-lead item category. As Bill explains:

…control valves have long lead times because the ASME has just issued new qualification requirements. So to use a valve in a given safety related application will probably require 18 months of qualification testing. We also have to factor in ever-tighter seismic requirements. Then materials procurement, machining, assembly and testing will probably take an additional 9-18 months, depending on valve type. So, we believe that if we get an order today for a nuclear grade valve it could take as long as three years to actually deliver it to the end user.

And Bill notes that these valves are used in safety critical areas. Not having them will delay the startup of the plant. Based upon this expected global increase in nuclear power plants, Emerson and other automation suppliers are increasing their capabilities to meet this demand.

Technology has changed greatly since these types of plants were built in the U.S. a generation ago. Bill describes digital technologies like Foundation fieldbus, which can be used in the balance of plant applications to provide better control and diagnostic information. Devices like digital valve controllers have completed Electric Power Research Institute (EPRI)-certification for use in this demanding application.

As energy producers seek ways to meet the increasing global energy demand, these preparatory activities are critical to meet challenging project schedules.

Update: I was just pointed to a great Béla Lipták article, The Third Industrial Revolution by a member of our DeltaV Twitter community. Béla describes the post fossil fuel world based on solar power and the role of process automation. It's well worth your read and I look forward to his book due out in August.

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April 16, 2008 in Foundation Fieldbus, in Plant Equipment, in Power, in Regulatory Compliance, in Safety | Comments (0)

Proven Measurement Installation Practices in Power Applications

by Jim Cahill

Inside the Emerson firewall, we have a growing community of bloggers who share their expertise with other Emerson folks and local business partners. Hopefully more of these voices will emerge over time, sharing their expertise externally with the world.

Rajesh NogajaI saw a post this week from the Rosemount team about installation best practices in the power industry. Power Industry leader, Rajesh Nogaja lead the effort to show how Rosemount products could be used to improve the power generation process.

On the external EmersonProcess.com website, the team created a graphical interactive application, Proven Installation Practices in Power Applications, to show these opportunities.

Power ApplicationsFor instance, if you click on the steam and gas turbine area of the graphic, the application takes you to a closer view of the steam, gas turbine, and balance of the plant graphic.

Once you click on the graphic to activate it, the graphic becomes dynamic and shows what measurement can be added to improve the operation of this part of the plant. Marker one points to the saturated steam flow measurement. It displays the best practice, in this case, having accurate measurement helps accurately calculate thermal cycle efficiency for these turbines.

I asked Rajesh from his experience which measurements were most often overlooked and a source for energy efficiency improvement. Rajesh pointed to condensate level measurements in heaters, condensers and deaerators. Accurate level control can optimize thermal cycle efficiency and improve plant heat rate. Guided Wave radar, which is immune to high vibrations and density changes, improves the condensate level controls under heavy load fluctuations. This measurement accuracy is not possible with conventional DP level or displacer type technologies.

Another often-overlooked area in most of power plants is accurately measuring main steam flow and extraction steam flow. These measurements are generally inferred from turbine first stage pressure or condensate flow. The direct flow measurement enables online heat-mass balance and optimizes part load and full load thermal efficiencies in the plant.

If you're responsible for optimizing a power plant and haven't done so already, look at these proven installation practices. I invite your comments on your experiences with key measurements and their impact on efficiency.

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February 5, 2008 in Measurement, in Power | Comments (0)

Getting Your Power Plant Unstuck

by Jim Cahill

Imagine that your power plant is about to have a scheduled outage. As the unit is ramped down and feed water control is taken over by the by-pass valves, you discover that the control valves refuse to close upon receiving orders from the level control system to do so. This is now the last straw for the operators who also have been fighting stability problems with these valves over the past several years. What do you do?

Well, if you know Emerson variability consultant, Eric Ascoli, you contact him. You may recall Eric from a prior post on stability problems at a sugar mill. He shared this story with me.

Instead of continuing with the shutdown, the station had to run at 20% power production for 12 hours costing them hundreds of thousands of dollars while the situation was diagnosed and corrected. A manual unit trip was not an option. The problem was aging pneumatic instrumentation that had locked up and blocked the valve positioner's operation.

Eric worked with a pneumatic specialist from Proconex, the local business partner for the power station. Their findings were that the operation of the pneumatic trip valve was not completely understood and its adjustment was slightly off. Also, the combined level control valves had a very large variation in installed valve gain and the unbalanced and aggressive controller tuning caused the instability the operators had been experiencing.

The challenge was to find a solution that would remove completely the possibility of such an event from happening again. It involved a short-term fix (servicing and adjustment of the pneumatics and modification of the characterizing functions for the valves) in preparation for the imminent scheduled power up. Additionally, Eric corrected the level controller tuning by using Lambda tuning after he analyzed and evaluated the process gain and empirically defined other important process parameters.

Their longer-term recommendations were to install digital valve positioners to replace the aging pneumatic ones. The same split-range control strategy would be maintained, but the valve performance would be improved through better positioning accuracy and dynamic behavior. The installation would be simpler and less prone to maintenance issues because I/P (current to pneumatic) converters could be removed. An even longer-term solution would be to replace the two split-ranged valves with one single start-up control valve to eliminate any crossover interactions.

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November 15, 2007 in Feed Water Control, in Power, in Process Optimization, in Variability Management | Comments (0)

Leading the Development of Fossil Power Plant Standards

by Jim Cahill

Congratulations to Gordon McFarland, senior power plant performance analyst with Emerson's Power & Water Solutions division for receiving the ISA's Standards & Practices Award. The award recognizes Gordon for his leadership in the initial development of fossil power plant standards, and for 25 years of continuous support and direction of those standards.

I caught up with Gordon who has 37 plus years in the power industry helping power producers get the most out of their control systems, including the Ovation system and non-Emerson systems. He applies this expertise as a primary technical lead in Premier Services performance improvement assessments. These assessments typically include a unit walk-down, plant personnel interviews, unit performance data collection, observation of unit operation, analysis of data and information collected, presentation of the results, and a final performance improvement assessment report. The team documents the actual unit control performance for deviation from the set points, control overshoots on ramping, ramp rates, unit net heat rate, forced outages and load de-rates directly and indirectly related to controls, and other parameters that may be important to overall performance.

Since 2000, Gordon has performed assessments on over 50 units, including drum type units, Once-Thru units, coal-fired and gas-fired units. On several of these, the performance was benchmarked by conducting "Before" and "After" performance tests to validate performance improvements on drum units, both coal-fired and gas-fired units, and on combined cycle units.

The goal of these assessments is to give power producers a roadmap to follow to achieve the possible unit performance improvements from improved control of the unit. These recommendations typically include field devices, control systems, operator interfaces, information and alarm management, and control room layout.

One thing Gordon and the team see almost every time in their evaluations is the need to have the basic regulatory control functions covered. This include single element and three element feed water control, steam temperature control, combustion control and unit front end control. The ISA SP 77 Fossil Fuel Power Plant Standards series covers the minimum recommended controls for these functions and they are a great starting point for good power plant control.

By applying his 37+ years of experience, Gordon has helped power producers in analyzing and improving their control performance and operating costs.

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December 13, 2006 in Power, in Process Optimization | Comments (0) | Trackback (0)