Insulate the Plant to Save on Utility Costs
BY AsphaltPro Staff
Editor’s Note: Some of the information presented in this article was used in the “Save Big Money on Your Plant’s Heating Bill” article in the January 2012 edition of AsphaltPro.
If the ambient temperature where you produce asphalt doesn’t typically remain above the temperature of your liquid asphalt cement (AC) or heat transfer oil, you’ll want to insulate piping and tanks. As you do with any equipment or accessories, you’ll then want to monitor and maintain the insulation.
Ron Henry of Heatec, Chattanooga, reminded owners: “Insulation of jacketed asphalt piping—or any other piping with heated materials—is extremely important. The first reason is fuel savings. Some customers tell us that insulated piping saves them about $15,000 per year. The second reason is conservation of energy.”
Considering the changes that have gone into effect concerning coal plants and power generation in the United States, electricity costs should start their sharp incline soon. During presidential campaigning, candidates of both parties told the voting public that electricity prices would necessarily rise during the second term. The reason for the utility price increase would be tied to the regulations the Environmental Protection Agency (EPA) would bring against the coal industry.
As of late 2014, new EPA rules are bringing hardship to coal-fired power plants. The Associated Press has reported that at least 32 such plants will close with an additional 36 such plants being affected in a costly way. The trickle-down effect means utility bills are doing exactly what we were told they would do: rise.
The good news for plant owners is utility costs can be controlled by cycling storage heating, keeping large storage tanks at a reasonable temperature and then boosting their material’s temperature prior to loading or use, and maintaining insulation to keep it functioning optimally. Normal weather conditions don’t destroy insulation, but ground men performing maintenance checks should include the condition of insulation on their checklists after high winds or hail storms and during annual winter maintenance. If you have concerns, point a temperature gun at the area of concern to measure how much, if any, heat is coming off the spot. An owner can easily see a 10 percent or more energy loss when insulation isn’t doing its job.
Rick Rees, the technical director for Stansteel/Hotmix Parts, Louisville, Ky., assured owners, “Once insulation and protection covers have been installed correctly, the system should last for years.” But consider what your plant upgrades entail. “Additions to hot oil circuits are sometimes made and not insulated,” Rees said. “This decreases the efficiency of the hot oil circuit.”
“The aluminum skin is critical to protecting the insulation,” Jim Grida of Reliable Asphalt Products, Shelbyville, Ky., said. “Make sure there are no breeches in the skin that could cause the insulation to deteriorate and the pipes to corrode. The joints of the skin should be silicone, or paste them regularly. Check them to make sure the seals are intact.
“Also, the hot oil lines can leak and further compromise the insulation and lines. Make sure all jumper lines are attached correctly and not leaking. Replace older insulation when it’s lost its value. Inspect sections of insulated pipe with a temperature gun to see if there is any significant heat loss. Those sections should be reinsulated using a newer insulation and skin.”
As Rees pointed out, insulating the piping on the HMA plant conserves fuel consumption, which minimizes the fuel costs of operating the hot oil heater. That means the hot oil system operates efficiently.
“With non-jacketed hot oil lines the transfer oil loses heat at a much more rapid rate, which in turn causes the hot oil heater to run constantly,” Grida concurred. “The hot oil heater isn’t allowed to run through its normal cycle and therefore greatly increases the heater’s fuel consumption. The contractor can easily see a 10 percent or more energy loss. Constant heating and reheating can cause a breakdown of the thermal transfer oil as well as build-up in the hot oil lines. He should also consider the condition of the hot oil heater and its efficiency.”
Pipes aren’t the only insulated portions of a plant that can affect costs. Take a look at the tank farm. Heatec’s Henry takes us back to a time when the thickness of insulation around asphalt tanks was not what it should have been.
“Years ago, three inches of insulation was standard and six inches was an option. But three inches is less than optimum. Six inches is close to optimum…” Henry said the 6-inch thickness has been standard on Heatec tanks for at least a dozen years.
“New equipment generally uses newer insulation technology,” Grida said. “The older tanks were primarily covered in asbestos, wool or fiberglass insulation, and the new equipment comes equipped with mineral fiber or dense foam insulation in thicknesses from 4 to 10 inches.”
Depending on your take, insulation of thicknesses beyond six inches is overkill—and could be detrimental to your purposes. “Thickness greater than six inches provides diminishing returns,” Henry said.
Tank insulation rarely sees damage, but older tanks may have new insulation needs. Rather than getting rid of an older tank, a producer may opt to re-insulate. Henry pointed out that this is something plant personnel, an outside contractor or the original manufacturer can do, but he said it’s sure easier to plan ahead and let the tank manufacturer do it at the factory instead of doing it in the field.
“Adding insulation to an old tank is very difficult to do in the field even if the tank is in top condition,” Henry said. “It’s very labor intensive. When buying a new tank, never get one with three inches of insulation with the thought of adding more insulation later,” he cautioned. “Increasing the insulation thickness is far more cost-effective when done at the factory instead of the field.”
Grida set producers’ minds at ease concerning maintenance, saying the owner always has the option to let someone else do the labor. “Most suppliers offer installation of the insulation as a service. We [Reliable Asphalt] have completed several jobs that involved skinning and insulating an existing tank. It not only diminishes heat loss, but it also provides a better aesthetic look for the tanks. There are several factors when considering a tank for refurbishing such as amount of coke in the tank currently and condition of the direct fire tube or coils.”
If you decide an older tank is a good candidate for updated insulation, you have options that could save big bucks on heating costs as new EPA regulations influence heating and other costs. Of course, the insulation you see every day around pipes and elbows deserves a close look for leaks or severe weather damage so you can keep high utility costs at bay there. Take a moment to consider your insulation condition around the plant and see what you save.
Insulation by the Numbers
Be aware of the actual costs involved in operating without at least 1-inch insulation in your piping. Look at the heat loss comparison between a typical HMA plant with 300 feet of piping and no insulation versus 1 inch of insulation.
The plant with no insulation on its pipes suffers a heat loss of 213,500 BTU (per 100 feet of pipe). Multiply that by 3 to equal 300 feet of pipe and you have a loss of 640,500 BTU per hour, for a total heat loss per day of 15,372,000 BTU.
The plant with 1 inch of insulation on its pipes sees a natural heat loss of 15,000 BTU (per 100 feet of pipe). Multiply that by 3 for a loss of 45,000 BTU per hour, for a total loss per day of 1,080,000 BTU.
You can save 14,292,000 BTU per day with the addition of 1 inch of insulation on pipes.
If you convert that to fuel, lack of insulation costs you 117 gallons of extra fuel/day (hot oil heater output), which means you spend about $350 more per day (at $3/gallon).
Source: Stansteel/Hotmix Parts