Xcel Energy XTRA April 14, 2008
Atomizers - Work helps boost plant performance
(Reprinted with permission)
It's high technology, not magic or fantasy. But still, a new tool recently put in
use at Denver's Cherokee Generating Station has some of the characteristics of a
crystal ball.
It gives plant staff the ability to "look" deep into the inner workings of the power
plant's scrubbers and atomizers - and then tell at a glance the past, present and
future condition of the complex equipment. Not surprisingly, that valuable information
will help maximize the scrubbers' performance and reliability.
"We've recently introduced the new technology of Radio Frequency Identification
(RFID) here at Cherokee," said Terry Perkins, a station supervisor at the plant.
"It's a tool that will give the mechanics, planners, schedulers and operators a
glance of how long an atomizer has been running.
"It also will keep track of the running time of each component, and allow us to
compare different vendor parts to maximize the reliability of the atomizers,”
he said. “Additionally, it will help mechanics who’ve never overhauled an
atomizer learn how to do the work beforehand."
Cherokee uses atomizer in its scrubber systems for Units Three and Four.
The atomizers use a lime-spray mixture to perform the critical task of
removing sulfur dioxide from the flue gas.
Traditionally, the monitoring and maintenance of Cherokee’s atomizers
has been somewhat of a hit-and-miss proposition. The work was labor intensive,
Perkins said, and there was limited information to provide in work orders after
maintenance was completed.
In addition, because the relative newness of the technology, there were no
standard method for tracking work orders on the atomizers, limited history of
current components, no way to compare materials or manufacturers, and no accurate
meters or alarms on the equipment that could provide critical information for
effective maintenance or avoiding failures.
However, during the 2005 Xcel Energy Scrubber Conference, Perkins came across
the new RFID Technology produced by RPM Solutions, Inc. He discussed the situation
with RPM representatives and the potential advantages of implementing the new
technology at Cherokee.
"We agreed there was a need to do better monitoring of the atomizers, and we
felt the RFID technology could assist us in doing effective preventive and predictive
maintenance of this expensive equipment," he explained. "A demo unit was installed
on one atomizer at Cherokee in 2006, and the RFID sensors on the remaining atomizers
were installed on the following year."
The RFID system uses wireless sensors to closely monitor the equipment’s condition
based on history. That critical information is sent to the central computer on
Cherokee’s atomizer deck, as well as to two table PCs containing procedure software.
The RFID system uses the sensor, computers and software to provide an at-a-glance
status of all of the plant's atomizers.
The monitoring system also provides flexibility for filing electronic data, he said.
It is search capable, and allows for data mining and for tracking equipment history.
In additional, operators can insert notes, photos, warning and other key information.
Procedures are customized for the specific power plant, and the software provides for
the generation of work orders and automatic e-mails regarding key maintenance activities.
"The immediate and up-to-date information on the status of the atomizers allows us to
know the run hours of all of the components of each of the atomizers," Perkins said.
"From that information, we're able to make fact-based decisions on when to most
effectively perform maintenance."
The RFID system will help with accountability of procedures, along with capturing of
the valuable "know-how" of staff through its documentation of maintenance activities,
he added. Plus, detailed step-by-step instructions for the maintenance and replacement
of atomizer equipment will be invaluable in training new employees.
"The web-based procedures on the PC tablets are a way of providing up-to-date electronic
manuals for our mechanics and operators," he said, “and can be customized based on the
plant's specific needs."
In addition to the advantages of standardized maintenance and operation procedures, and
the increased efficiency and reliability those bring, the RFID system should bring significant
savings in maintenance costs, Perkins said. The system's budget and inventory control will
allow for effective cost evaluation of each atomizer, as well as for comparing vendors,
equipment and test components.
"The information provided by the RIFD technology ultimately should help maximize the life
of all atomizer components, and minimize needless inspections and equipment handling," he
said. "From that information, we'll be able to accurately determine the runtime of each
individual atomizer.
"And one key advantage of the RIFD system is that is allows us to closely monitor the
useful life of each atomizer component and replace it before it fails, which can shorten
the life or destroy other atomizer parts."
While it's too early to gauge the overall results and effectiveness of the RFID system
at Cherokee, Perkins said he is confident that the recently installed technology will
bring significant improvements in maintenance, reliability and cost effectiveness to
the power plant.