Dec. 9, 2003 — In what is the first commercial application of fleet-wide optimization using real-time data, Emerson Process Management announced that Xcel Energy has installed its SmartProcess® Fleet Emissions Optimizer module to optimize SO2 emissions at three Denver-area power generation facilities.
This announcement comes just one year after Emerson introduced this software, which uses computer models and artificial intelligence to improve environmental compliance and cost efficiency over a fleet of generating units.
The module, which began running in September 2003, is to be used in conjunction with Xcel Energy’s voluntary Metro Emissions Reduction Program (MERP) for the metropolitan Denver area.
Through the installation of additional emission controls at three Xcel Energy power plants (Arapahoe, Valmont and Cherokee stations), Xcel Energy seeks to optimize the SO2 emission rate so that the total amount of SO2 produced by these units does not exceed the yearly cap (10,500 tons of SO2 per year), and ensure that the flue gas is scrubbed in the most cost-effective manner.
The SmartProcess Fleet Emissions Optimizer module was designed to determine the optimum SO2 emission rate for the FGD (Flue Gas Desulfurization) systems at these generating facilities.
“Environmental performance is extremely important to Xcel Energy,” said Alan Davidson, manager of capital projects for the Energy Supply business unit at Xcel Energy. “We are currently gathering data through this system and hope to soon use it to control our scrubbers. The software is a decision-support tool that weighs a number of interrelated variables to determine the emission rate set points for the scrubber units so that we meet our MERP SO2 goal as efficiently as possible,” Davidson said.
The optimization software is further enhanced by the SmartProcess Fleet Emissions Optimizer Portal, which provides a single window into the plants, enabling plant personnel to remotely view the output of the SO2 optimization program, plant process graphics and other relevant information.
The portal also allows what-if analysis through the browser to determine the cause and effect of tweaking the variables.
“Via secure Internet access, designated personnel can see into the plants and monitor the program on a real-time basis,” said Davidson. “This valuable tool helps our personnel to keep close tabs on SO2 compliance – even when they are off site.”
Xcel Energy operates three facilities with coal-fired units in the metropolitan Denver area: Arapahoe Station, a two-unit, 156-megawatt, steam-electric generating station; Cherokee Station, a four-unit, 717-megawatt, steam-electric generating station; and Valmont Station, which has one 199-megawatt steam-electric generating unit.
The plants are located several miles apart, however, each is connected to the corporate network, making it possible to gather data from each plant and deliver it to a central location.
The optimization software receives all of the primary process data from each of the plant’s control systems.
The software also evaluates a number of related factors, including data collected from the Continuous Emission Monitoring (CEM) system located at each plant; the load/outage schedule; coal train and load forecast data; as well as dry reagent, water and waste disposal costs associated with the two types of FGD systems used by the units – Dry Sodium Injection (DSI) and Lime Spray Dryers (LSD).
Based on this information, the optimization software sends FGD system setpoints from the central computer to each of the plant’s control systems. The actual amount of SO2 being emitted from each plant and the predicted yearly SO2 amount are constantly updated so that the software can calculate the difference between the two and make the necessary adjustments.
The software responds dynamically to plant operating conditions. For example, if a scrubber goes offline, the software weighs the overall load against the target compliance and costs to determine whether it is necessary to run gas units – and for how long – until the scrubbers go back online. “The decision support offered by the module provides the information necessary to ensure we meet the objectives of the MERP,” said Davidson.
When modifications have to be made, there are many combinations of actions that can eliminate the error. However, some combinations are better than others, according to Jeff Williams, director, SmartProcess Advanced Control Solutions, Power & Water Solutions industry center of Emerson Process Management.
“Some FGD systems are more efficient than others, while others cost less to operate although they are not as efficient,” he explained. “The goal is to find the solution that satisfies SO2 requirements at minimum cost.”
Based on the early indications of the success of this program, Williams believes it will be adopted by others in the power industry looking for ways to cost effectively manage fleet-wide emissions reductions.
He explains that the Fleet Emissions Optimizer offers a competitive advantage to power generators because it can impact the bottom line in a number of ways. “The ability to assure environmental compliance by automating a process previously done manually and increase equipment efficiency and lifespan makes a compelling case for adopting a fleet-wide approach,” said Williams.
About Emerson Process Management
Emerson Process Management (www.emersonprocess.com), an Emerson business, helps businesses automate their production, processing and distribution in the power, water and wastewater treatment, chemical, oil and gas, refining, pulp and paper, food and beverage, pharmaceutical, and other industries.
Emerson’s Power & Water Solutions division (www.emersonprocess-powerwater.com), formerly Westinghouse Process Control, is a global supplier of advanced distributed process control and information systems. The Pittsburgh-based company develops plant-wide process control solutions for the power generation, water treatment and wastewater treatment industries. Power & Water Solutions plays a key role in the Emerson mission of combining superior products and technology with industry-specific engineering, consulting, project management and maintenance services.
St. Louis-based Emerson (www.gotoemerson.com) brings technology and engineering together to provide innovative solutions to customers in process control; electronics and telecommunications; industrial automation; heating, ventilating and air conditioning; and appliance and tools. Sales in fiscal 2003 were $14 billion.