High-tech maintenance at ethanol plants

Ethanol plants tap into vibration, ultrasound, infrared and laser technologies. This article appears in the November issue of EPM.
By Susanne Retka Schill | October 20, 2015

A bearing race sits on a shelf at Elkhorn Valley Ethanol LLC in Norfolk, Nebraska, as a testimony to the maintenance department’s high tech tools. A technician using vibration analysis on a motor turning at 1,700 RPM told the maintenance crew that the front bearing had an inner race defect. “I laughed when he first told me that,” recalls Matt Werzyn, maintenance manager, “but we took it apart and, lo and behold, there was a hairline crack in the inner race of that bearing.”

Vibration analysis, ultrasonic readings, thermal imaging and laser alignment are among the newer technologies in the toolkits of the maintenance departments at ethanol plants. Along with their impressive capabilities come impressive price tags—anywhere from a little under $2,000 for a single tool to $20,000 for a more sophisticated system with sensors and software.

For Werzyn, those tools help his department stay ahead of the challenge of keeping equipment running smoothly. “We’re a 50 million gallon plant,” he says. “I have close to 125 motors, 80 pumps, five fans—and everything on that list has a least two bearings. There’s a lot of stuff moving in a plant.”

Elkhorn Valley started using vibration analysis right away when the plant was commissioned in 2007, Werzyn says, so they had a better experience with reliability than he encountered at the first plant he worked at.  Instead, he measures performance by tracking unscheduled downtime. “We have had zero unscheduled downtime for the past six months. So, having all those high-tech gadgets does pay off. The initial outlay is pricey, but it pays for itself.”

High-tech tools and a new maintenance emphasis have also had an impact at KAAPA Ethanol LLC in Minden, Nebraska. “The reliability of the plant has exponentially increased,” says Dan Mainwaring, who began managing the maintenance department at KAAPA Ethanol a couple of years ago, with a goal of improving predictive and preventive measures. Like Elkhorn Valley, KAAPA Ethanol has a company come in monthly to do its vibration analysis, covering all the equipment at least once each quarter or six months, looking for early indications of bearing failures or other issues.

“A good example is cooling tower fan gearboxes,” Mainwaring explains. Enclosed in a cell on the cooling tower, there’s no direct access for a maintenance check on those gearboxes while operating. Remote vibration sensors were installed during a shutdown with wires running to a box outside of the cell, where the readings can be safely taken while running. The cooling tower fans are critical items, he adds, particularly in the summer when losing a cell might mean a fermentation would begin overheating, potentially killing off yeast and production. 

Infrared (IR) scans are also done at KAAPA, looking for issues with electrical panels, motor control centers and switchboards. “Obviously, that’s another one of those things you don’t normally access and open panels because of safety, so you don’t know where you have hot spots or loose wires or a breaker that’s ready to fail,” Mainwaring says. “We hire a company that comes in and they will get their arc flash gear on—and following other safety requirements—they’ll open the panels and use an IR scanner that will scan all the connections.”

Ultrasound readings are another technology used to find electrical issues. Ultrasound detects the air disturbance created by a pressure differential or friction, explains Blake Canham, regional manager UE Systems Inc., and can detect those disturbances without opening panels. Ultrasound has other uses. Perhaps the simplest is finding leaks in compressed air lines or malfunctioning valves.

The newest application catching on in the ethanol industry is using ultrasound-aided greasing. “It’s helped us by answering the age old question—if it needs grease, how much do you put in?” says Werzyn. The old school of thought was two pumps, he explains, but using the new tool, “a lot of times it will only take less than a pump. We’ve been overgreasing.” Overgreasing, he adds, is considered the biggest cause of bearing failure.

Maintenance Goals
High-tech tools aid other routine maintenance at plants. Laser alignment tools are widely used whenever pumps or motors or fans are worked on, to be sure they get put back together correctly.  “Before laser alignment everything would be aligned within tolerances with multiple sets of dial indicators,” recalls Werzyn, adding that alignment itself is as old as mechanics. The ethanol industry has grown to see laser alignment as a must, he says. “You’ve got to have it, just for the sheer speed. If we go into a shutdown and my guys are going to open 14 pumps, that’s 14 alignments.” That many alignments might have taken two days with old school methods, he says, “Now an alignment can be done in 15 minutes.”

While some of these high-tech tools have been used in industrial settings for a couple of decades, new models are being designed with more features, requiring less-highly skilled operators. Operators for early models of vibration analysis take 12 to 24 months to acquire the skill set to use the equipment, explains Brian Shanovich, product line manager with VibrAlign Inc. With fewer highly skilled trades people available these days, particularly in rural areas where most ethanol plants are located, his company is increasingly focused on equipment with added capabilities. “Our shaft alignment and the Hawk (machine diagnostics) are designed for people who don’t need to have that skilled or multiyear millwright or mechanic background. The tools are designed to help them go through it step by step. They are very tutorial in how it helps people go through the process.”

As these high-tech tools become more user friendly, he stresses, proper training is essential to understand the fundamental principles. “These tools are not a panacea,” he says. “When we do alignment or vibration training, we talk about the basics before we get to actually touch the buttons and teach people what to do.” The goal is to get machinery life to where it could be, he adds. “The bearing manufacturers say if you properly align and lubricate the bearing and balance the machine, it should last virtually forever.” And, while the average pump life is two and a-half to three years, according to one study, world class industrial plants get 10.5 years.

Reducing overall maintenance cost is another big goal of the high-tech tools, says Dennis Uhl, a machine reliability specialist with R.S. Stover Co., working with the Emerson Process Group. Good software is a big part of the new systems, he says, describing how Emerson’s CSI 2140 allows a reliability technician to build virtual machines in the computer software. Readings gathered in the plant can then be used to analyze machine health. “This is about knowing the problem sooner,” he explains. “Plants want less parts on the shelf and to know ahead of time so they can go to the vendor and ship the parts in plenty of time—and not pay for that expedited service—and schedule the time to do the work.”  He cites a reliability study that shows unplanned work involved about 25 percent wrench time which, when planned, goes up to 55 percent. “Planning the work, you get more done in a day and it’s more productive work,” Uhl says, adding that top tier industrial plants set a goal of keeping annual maintenance costs at 3 percent of the replacement value of the plant. 

Unscheduled downtime is a big expense. Werzyn says he hasn’t done the math for a few years, but at one time, he calculated the cost of unscheduled downtime at $35,000—per hour. “The rule of thumb is, it’s a year’s wages per hour,” he says, adding that it does vary. “The expensive tools are necessary. They’re not a luxury item—they are another tool in our toolbox. If you want to run and stay running well, you’ve got to have them.”

Author: Susanne Retka Schill
Senior Editor, Ethanol Producer Magazine