At the 2016 International Production and Processing Expo in Atlanta, Georgia, U.S., Charles Stark, associate professor in feed technology at Kansas State University, gave a presentation on ways to improve efficiency and reduce energy costs in a feed mill.
Stark said addressing these issues will “improve your bottom line, increase your competitiveness in the marketplace, protect your business from rising energy prices, reduce carbon emissions and help you stay ahead of government regulations.”
Having visited many feed mills during his years in the industry, Stark said facilities that are not energy-conscious are missing opportunities to improve profitability.
“I’ve seen mills where you go into the warehouse and every light is on,” he said. “Or you go to do a steam trap audit and the steam traps are sticking open. All they’re doing is wasting energy.”
While the idea of creating an energy management program might seem overwhelming, Stark said a good place to start is using the American Feed Industry Association’s energy savings guide.
“It’s a very good way to begin the process,” he said. “You can go through and highlight which items have the potential to save you the most money. We’re not asking you to create a form because it already exists.”
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Creating a conservation culture
Stark said energy conservation programs are doomed to failure unless top management makes it a priority and then leads by example for its employees.
“It starts at the top and works its way down,” he said. “You need to have commitment from management. You can say you’re going to start doing things in the plant, but if management is unwilling to provide the money or resources to do those things, you may have a bunch of great ideas that nobody is implementing.”
Stark said a good energy conservation program is not run by committee. An individual must be designated to have clear responsibility for driving the program and making sure specific goals are met. The program also must be properly staffed, with enough people involved to carry out important energy savings tasks.
A critical part of the program is having a data monitoring process in which energy usage data is compiled and evaluated in order to determine what changes can be made to save energy. The problem with some companies, he said, is their process doesn’t go beyond data collection.
“If you collect data just so you can have it on the report and no one looks at it every week, then the data is not going to be very valuable,” he said. “You should be using the data to hopefully make a positive change in the process.”
He said a successful energy savings plan is not altered when the price of energy and fuel drops.
“A boss of mine told me a long time ago if your management philosophy changes when you have $70 hogs as opposed to $20 hogs, then you probably aren’t managing correctly at $70 hogs,” Stark said. “Your philosophy should be consistent regardless of the other variables.”
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Boilers
Stark said the boiler is probably where feed mills spend their greatest percentage of energy, but there are opportunities for energy savings that many mills overlook.
“About 75% of BTUs in a boiler are actually used,” he said. “Everything else is sent into the environment or someplace else. You have to look for steam leaks, radiation, condensation, boiler blowdowns.”
He said an easy way to save money is to make sure the water softener in the boiler is working correctly. “If you just build up a little bit of scale, say 1/32nd of an inch, it is estimated that it will cost you 8.5% in energy over a year’s time,” he said. “At 1/16th of an inch, it’s 12% additional fuel every year. I learned this the hard way. I found out the water softener hadn’t been working for a period of six months in one of my feed mills. When we opened up the boiler we had a lot of scaling issues. It cost me $5,000 to fix the water softener.”
He also recommends using an economizer, which returns warm water to the boiler so it doesn’t take as much fuel to heat it up, also heat recovery from routine boiler blowdown can be used to preheat make-up water. Stark also suggested having a boiler efficiency analysis done at least once a year to make sure it is running at peak efficiency. “Just like a car, you need to make sure it’s tuned up,” he said. “The cost to bring someone in to do that type of inspection compared to the cost of wasting fuel is much less. The return on investment is very high.”
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Air compressors
Stark said one of the easiest ways to save money in a feed mill to identify areas where air pressure can be reduced. He said millers should examine each piece of equipment that is operated on air pressure and determine the minimum air pressure requirement. He said installing a reserve air tank for times when the mill is running at peak demand can allow equipment to run at a lower psi (pounds per square inch) the rest of the time.
“I almost invested $30,000 on a new air compressor for the receiving area until I had a consultant come in and say if I just put a $3,000 air reserve tank in that area the problem would be solved,” he said. “Sure enough, we put in the reserve air tank and the air compressor could actually keep up because we had that extra reserve there. That saved me about $25,000.”
He also emphasized the importance of checking for air compressor leaks. “My best advice is to turn the air compressor on during the weekends (with the equipment off) and listen for the hissing,” Stark said. “If you look at the cost of a 1/8-inch leak over a half-inch leak in an air compressor over time on an annual basis, it adds up in a hurry.”
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Maintenance
Diligent maintenance of equipment is a sure way to save money, Stark notes, although some mill managers are hesitant because properly maintaining equipment does cost money up front.
“If you double your cost of maintenance, which means increasing the frequency in which you maintain hammers and screens, you will actually decrease your total energy cost,” he said.
Making sure filters are clean, belts are tight and bearings are not worn can all lead to energy savings, he noted. For instance, it takes more mechanical energy for a piece of equipment to operate with a worn bearing.
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Lighting efficiency
An aspect of energy savings that is often overlooked in an intense energy-consuming environment like a feed mill is lighting efficiency, Stark said. The first step is to go through a feed milling facility, including the office and laboratory, and count how many fluorescent and incandescent lights are in the plant and how many of them are on when nobody is in the room.
“I’m going to a lot more plants that have sensors that turn lights off in part of the plant that are not being used,” he said. “It’s not a huge investment but it does save money.”
Other office items that can simply be turned off when not in use to provide savings are computers, copy machines, coffee machines, space heaters and fans.
“What does it cost to have a coffee machine running all day to keep the coffee hot? Probably pennies but as part of an energy management system it all adds up,” Stark said.
The same principle can be used with feed mill equipment.
“How many pieces of equipment do you have running that aren’t doing anything? A hammermill may be running empty or a bucket elevator. But before you shut it down you need to take cool down time into consideration,” he said. “If you know you’re going to start it back up in 15 minutes, it’s probably not worth shutting down. But if you know you won’t be using it for another hour or more, it is worth shutting down the equipment rather than running it.”
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AFIA energy management guidelines
In 2014, AFIA published an updated Energy Management Guidance Document. The six-chapter guide covers state regulations, the organization and development of an energy management program, feed industry audits, calculating energy costs and methods for conserving energy.
The document is designed to help feed manufacturing facilities understand how to develop benchmarks within their companies and offers suggestions for improvement based on the findings.
Key areas the document provides details on are: calculation of electric bills and how to reduce electricity usage in a feed facility; energy audits specific to natural gas consumption, operating temperatures of a boiler, peak demand usage and more; and the proper maintenance of boilers within a mill, especially if operators are pelleting feed or flaking grains.
