Plant Upgrade helps Blythe Construction Meet Sustainability Goals
BY Rick Jay
As one of Southeast United States’ premiere infrastructure construction firms, Blythe Construction Inc., operates 13 asphalt plants across North and South Carolina, producing more than 1 million tons of hot mix and recycled asphalt annually. It is a source of pride for Blythe that every one of its asphalt plants is a recipient of the coveted Diamond Achievement Commendation for operational excellence from the National Asphalt Pavement Association (NAPA).
Covering aspects that range from plant appearance to safety to regulatory compliance and community relations, the Diamond Achievement Commendation also includes a sustainability component that gauges a facility’s effectiveness at implementing environmental goals. For Blythe and its parent entity, Eurovia Company, based in Paris, France, the environmental focus has increasingly become a priority within its operational practices. Because of this, Eurovia has set forth an initiative to reduce emissions from its asphalt plants by converting the plants to electric heat for their asphalt tanks, hot oil heaters and more. The first Eurovia-owned U.S. plant to make this switch is Blythe Construction’s North Plant on Reames Road in Charlotte, North Carolina. The company completed the upgrade September 2019.
Driving Towards Environmental Excellence
“Eurovia’s emphasis has been to change its asphalt plants overseas to all electric in an effort to reduce emissions,” Tim Mitchell said. He’s the North Carolina plant manager for Blythe Construction Inc. “They now are working to upgrade our plants here in the U.S. to electric heat. At the North Plant tank farm, we installed three new asphalt cement tanks, five new silos and a hot oil heater this past summer. We upgraded all three tanks and the hot oil heater to include drywell-style electric heat, rather than propane burners, because the burners are inefficient and create emissions.”
Mitchell explained that the three vertical 30,000-gallon asphalt cement tanks were all manufactured by Meeker Equipment Company of Belleville, Pennsylvania. Each is heated with a Lo-Density® Unitized Storage Tank Heater from Process Heating Company (PHCo), based in Seattle, Washington. The plant’s new hot oil circulating heater also is manufactured by PHCo and features Lo-Density drywell-style heat. “Eurovia had specced everything out, and they specified the drywell-style electric heaters,” Mitchell said. “Meeker was our tank supplier for the project.”
PHCo’s Lo-Density Unitized Storage Tank Heater heaters are often specified into both new and existing asphalt tanks, as they can easily be installed into any horizontal or vertical above-ground tank or vat, even as a retrofit. The unique low-watt-density drywell-style heaters dissipate controlled heat as low as three watts per square inch on the heater’s sheath to prevent coking or damaging of temperature-sensitive asphalt or emulsions. These materials often experience damage when too much heat is applied to them too quickly. Asphalt and emulsions ideally should be heated by a carefully controlled system that reduces their viscosity.
With the PHCo’s indirect heating systems, like its Lo-Density Hot Oil Circulating Heaters, heat from electric energy is transferred to the oil, which then carries it to the area or process where it is needed. Using PHCo’s unique, patented Coil-Lock-design heating elements, which also reside within a drywell, the hot oil transfer heat units dissipate controlled heat as low as eight watts per square inch on the heater’s sheath, eliminating coking or carbonization of the transfer oil.
As a means for Eurovia and Blythe Construction Inc. to meet their environmental goals, the Lo-Density heat provides the emission-free benefits the companies were seeking.
Keen on Clean
Since the plant was brought online, Mitchell said he has been pleased with its performance. “Moving from tank to tank, the (material) temperature can drop some. But with it now being self-controlled at each tank, the Process Heating units keep everything at an even temperature,” he said.
“Because the heating elements are in a drywell, you have more control over the heat. With the natural gas burners we used before, we always had issues with the asphalt or hot oil first cooling then spiking in temperature—creating problems with coking and burning,” Mitchell continued. “I was somewhat familiar with this style of heater prior to the upgrade. We have one Process Heating heater at another location in an asphalt tank. In my experience, it has maintained the heat beautifully in that tank—controlling it a lot better, without coking in the bottom of the tank or around the elements.”
With the completion of its North Plant upgrade, Blythe Construction Inc. will be following a plan set forth by Eurovia to upgrade each of its U.S. asphalt plants in turn.
“As older equipment becomes inefficient and needs to be replaced, we will continue to upgrade to the low-(watt)-density electric heat,” Mitchell said. “In 2021, there are a set of tanks in Raleigh (North Carolina) that will be replaced, and we intend to use the Process Heating Lo-Density heaters for those.”