The wireless and mobile movement that has swept across the globe hasn’t stopped short of cell phones and tablets. Adaptation of smart, sensory and remote monitoring technologies has been ongoing in the power industry for many years, and innovations have only just begun. Via these applications, plant operators are seeing reduced installation and maintenance costs, safer operations, increased efficiencies, and in the case of emergencies or unplanned down time, are able to conveniently access real-time plant data while being nowhere near the facility.
For Stacy Cook, plant manager of Koda Energy, a combined-heat-and-power (CHP) biomass power plant in Shakopee, Minn., being able to access and view control capabilities from remote locations proved highly valuable. Provided by Rockwell Automation, Cook explains that Factory Talk software is set up with the ability to log in to the system from a network. Purchasing extra licenses and installation of a Citrix-based network portal means remote users, once logged into the network, can navigate to the server where the Factory Talk software resides. “So any time I am away from the plant and have an Internet connection, I can log into Citrix, get onto our internal network, navigate to our control system server and log into Factory Talk after selecting whether I want to have control capabilities or a read only file,” Cook says. “Once I am into the system, the screen on my mobile device has the same functionality and appearance as if I were sitting at the operator control station in our plant control room.”
Having that capability recently proved extremely useful to Cook. “About a year ago, I was in Central America hiking on Mt. Chirripo with my wife,” he says. “While up at the ranger station base camp at 11,500 feet, I found that they had a radio-based Internet connection that I could jump onto. When I logged onto our email server, I had several messages from the plant identifying problems they were having at the CHP plant.”
Cook was able to use his smart phone to log into the control system. “From the middle of nowhere in Costa Rica, I could help troubleshoot their issues and provide guidance.” he said. “Otherwise, they would have struggled with an upset condition without the additional support from me until I got off the mountain that evening and had a cell connection to speak directly with my operations staff. It is so much better to have the ability to see what they are seeing from the operator chair, and less opportunity for a miscommunication through a verbal or email.”
While Cook benefitted from wireless technology while being offsite, many companies, such as Emerson Process Management, are tweaking already robust product lines focused on onsite efficiency. Bob Karschnia, vice president of Emerson Process Management’s wireless business, says the bulk of this company’s business segment is centered around wireless instrumentation and systems associated with helping customers increase visibility and provide better plant control. “[Applications] that keep people safer, make plants more efficient, and keep equipment up and running,” he says.
Since biomass power is a newer industry than the oil refinery business, many companies are able and desire to adapt the latest and greatest when they build. Some, however, are making changes to existing plants.
At the Elektrownia Stalowa Wola S.A. power plant located in Poland, Emerson’s Rosemount wireless transmitters are being used to enable thermal monitoring of biomass gasification precombustion chambers. There, new temperature data is being transmitted over a network to operators to ensure that the ceramic walls of the chamber are not damaged by stress fractures through overheating.
“There, they have rotating kilns pushing the wood chips through, and that’s something you can’t wire very well,” Karschnia says. “Getting multiple measurement points along kilns is a problem—they are long, 20 to 30 feet, and the temperature varies from one end to the other and the middle. You have to be able to get a clear look at the temperature profile across the kiln and control it accordingly, so we put transmitters along it to provide a better efficiency view of what was going.”
This provides the operator with the information needed to protect the chamber from overheating. Should temperatures go beyond 350 degrees Centigrade, an alarm is triggered and the operator can adjust the amount of air going into the chamber or reduce the heating of the biomass. If required, the fuel for the chamber can be shut down completely. Should the operator not react in time, the system can shut down automatically. A further transmitter has been installed nearby and acts as a router, strengthening the self-organizing wireless network by providing an extra route for signals to pass through. The device also measures the ambient temperatures.
“That’s been a big thing for them, having the ability to better see what’s going on in that kiln, and as a result has been able to increase the efficiency of the process.” Karschnia adds.
In Faenza, Italy, the 13.7-MW Enomondo power generating plant at Caviro Distillerie is using Emerson Process Management’s smart wireless devices to monitor a complex fuel pretreatment operation, an incineration process, and a new boiler, and has seen an estimated 5 percent increase in overall efficiency. The wireless system meets the plant's predictive maintenance requirements, and continuous data made available by the wireless network enables personnel to identify performance degradation trends that signify potential problems.
“In this case, they could have done something like it with a wired solution, but the downside of wires is twofold,” Karschnia explains. “One is that it causes complexity when trying to do something. If you wanted a wired Ethernet connection from one end of your house to the other you to have a contractor come in, tear up the walls, put in the wire and repatch, and it takes a while, because there is a lot of complexity. If you go to Best Buy and get a wireless router, however, you’re up and running right away. That’s the advantage of wireless, at Enomondo it allowed them to get that data into their system much more efficiently and quicker than they could have done with a wired system.”
Karschnia says wireless systems are usually about half the cost of a wired system, but wired systems have one advantage. “The advantage of a wired system is that its powered all the time…wireless has batteries that have a limited life time. We have high-end, specialized batteries, and run our system to optimize transmitter energy usage such that batteries can last up to 10 years, but an operator gets measurements on a slower rate.”
Wired systems may provide readings every half second. With wireless, one can achieve them once every two seconds, but it will cut the battery life down to about three years. “If you do it smartly, and recognize that a boiler’s temperature doesn’t change very quickly, a once-per-minute-update rate isn’t a problem. If you’re controlling something more high-speed like a liquid flow line, which can change very rapidly, you need higher update rates.”
For boiler monitoring specifically, Clark Reliance recently released an upgrade of its boiler-level indication system, which has been installed in over 10,000 boilers in the U.S., according to Jim Kolbus, product manager.
The EyeHye SmartLevel Boiler Level Indication System has been on the market since 1959, and has evolved through the years. It consists of sensors located in a vertical pipe manifold, locations of which are agreed upon by the customer or original boiler manufacturer, and is used to indicate actual water level in the boiler drum. This device is also approved for use as a limit control, Kolbus says, so it can be used for alarming or tripping the boiler to shut down for high or low water.
“The big advancement with the smart control is that we’re telling the operator when to conduct maintenance,” Kolbus says. “There’s a blue light that illuminates on the indicator to tell the control room operator that the column or probes need cleaning or a blow down. The idea with the Smart System is that we detect a contamination build up on the sensors before it’s to the point where we’d get an incorrect signal.”
If a customer has a blue light come on in the control room and advises operations to conduct a blow down on the system, one of two things will happen: steam cleaning of the probes will correct it and the blue light will go off immediately, or the blue light remains on, meaning the blow down didn’t solve the problem and that there’s a bad sensor. “By going to the control unit, the module related to the particular probe will have a companion blue light on it and it will identify which particular sensor the customer has to go after,” Kolbus says.
With a traditional system, a contaminated sensor may identify a problem when there wasn’t one, or indicate water where there is none. “If they blew down a column before with regularity, one would see this—if any lights remained on, there was a dirty, shorted or contaminated probe. They would see which lights stayed on and go troubleshooting,” Kolbus says. “Here, you’ve got a warning system that lets the operator know there will be a problem before it happens. In these days of everyone doing less maintenance than ever before, this is being viewed as a value-added function, and we’re getting very good feedback for the people who learn about it.”
The EyeHye also has a green system status light, an indicator that lets the operator know all internal communications are working correctly and turns red upon any internal component failure.
“With our system and other manufactures' systems with conductivity probes, we traditionally recommend weekly blow downs,” Kolbus says. “We have customers who tell us when they went through boiler training they have done blown downs once a day or shift, and then there are people who do once a week, which is what we recommend, and those who say, ‘we’re short on maintenance people here, nothing’s leaking so I’m not touching it.’ As we get into this trend in the power industry of fewer personnel and cutbacks, having a device that smartly tells you when to do maintenance is being widely perceived as a benefit.”
Already have an EyeHye and want the upgrade? Three field test installations were done in less than a day, according to Kolbus. “We used existing field wiring, removed an old control box and installed a new one, and the indicators for the control room have the same physical size as earlier models so no cutouts required. People tend to get very nervous about having to enlarge openings in control room walls where there is other instrumentation, as they don’t want tiny chips produced from cutting or sawing walls to get into instrumentation and potentially cause other failures.”
Overall, deciding which technologies will improve a plant’s bottom line and achieve safety, emission and other goals isn’t a simple task. “The challenges plant managers face are always complicated,” Karschnia says. “They will always have multidimension problems they’re trying to solve—trying to reduce cost, increase efficiency, help with safety and environmental issues, and they don’t always line up.”
Sometimes, a plant has to spend a lot of money to be more efficient, and that can lead to being cost-prohibitive, he adds. “Wireless has dramatically changed that cost-benefit curve, such that you can actually get all of this additional insight on how to run your plants safer and more efficiently at a much reduced cost. As a result, you can see notable improvements in the performance in your plant, and do that with the budgets that you have today.”
Author: Anna Siimet
Managing Editor, Biomass Magazine