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Paratherm has become the trusted name among asphalt plants for ensuring their heat-transfer fluid systems provide consistent heat to keep the asphalt moving. “The asphalt products need to be kept warm to be fluid,” Sales Engineer Mike DiGiacomo says. “Our heat-transfer fluid gets heated and circulated to maintain the product’s temperature during batching and storage.”

The Conshohocken, Pa.-based company began more than 20 years ago and has become a leader in the development of heat-transfer fluids, fluid analysis and hot oil system cleaners. Paratherm’s products can be found worldwide through its global network of distributors in more than 20 countries. Its sales engineers are trained to help select the appropriate heat-transfer fluid and will provide 24/7 technical support and service. “We have more technical experience than any of our competitors,” DiGiacomo adds. 

Paratherm’s heat-transfer fluids are used in more settings than hot-mix asphalt production. They also have applications in petroleum refining, liquid terminals, gas processing, biodiesel, industrial laundry, poultry and meat processing, and plastic molding and extrusion. The company offers nine heat-transfer fluids specialized for specific industries and applications. Asphalt plants, for example, want heat-transfer fluids to reach 300 to 400 degrees F to maintain the asphalt cement’s viscosity in their batch plants, tanks and silos.

“Each product is tailored to an industry or industries based on temperature range or other engineered characteristics,” DiGiacomo explains. “We have fluids for low-temperature applications, negative temperatures and high-temperature products that go up to 650 degrees F.”

To ensure systems are running correctly, Paratherm’s technical experts perform fluid analyses on samples of both mineral oil-based heat-transfer fluids and synthetic fluids. This program enables customers to correct problems before they become expensive, avoid complete heating system failure or just make sure the fluid is still in good condition. 

The fluid analysis program is unique at Paratherm because it goes beyond only running laboratory tests that measure properties of the fluid. It uses the in-house laboratory test results to make a total system analysis through its extensive knowledge of equipment and processes, and monitors historical results on a given system for process trends and signs of equipment issues. 

Paratherm’s fluid analysis can determine whether results are normal, if equipment problems exist or whether operational issues are causing the fluid to degrade. By performing an analysis on a fouled system, Paratherm engineers are also able to recommend the appropriate hot oil system cleaner. The company provides three hot oil system cleaners that can restore a system’s performance, dissolving sludge and carbon lumps with minimal downtime. 

Overcoming Challenges

Paratherm’s fluid analysis program was able to catch a vital flaw with the heat-transfer fluid that a major city on the West Coast was using to keep its asphalt heated. The company’s thermal fluids are used to heat asphalt tanks, mix plants and storage silos that supply paving material to one of the largest cities on the West Coast. This city has more than 6,000 miles of streets and repaves about 270 miles annually, not including repairing potholes and emergencies. 

One of two plants that supply the city’s needs is a 5,000-pound batch plant that prepares 1,600 tons of asphalt every working day. The asphalt is pumped into liquid storage tanks and sent through a piping system to the weigh scales. It is mixed with aggregate that was previously heated to 340 F to remove any residual water. The mixed asphalt is moved to storage silos where it is then loaded into trucks for jobsite delivery. If there is bad weather and crews cannot work, the heat transfer fluid has to keep the asphalt hot at the plant for up to a week or more. “It is imperative that the plant runs smoothly just to keep up because any delays that slow or temporarily halt production can put the city seriously behind schedule,” the company explains. 

This city was using various brands of heat-transfer fluids, but overtime they would degrade, causing a loss of heating capability in the tanks. When enough heat was lost, jackhammers had to be used to remove hardened asphalt. Paratherm helped get the system running again and had the city replace the degraded hot oil with a Paratherm heat-transfer fluid. It was able to keep the new oil within specs by monitoring it with regular fluid analysis, thus avoiding a repeat of the expensive plant failure.

To ensure asphalt plants stay operational, Paratherm offers training sessions on using its heat-transfer fluid to its customers in addition to performing its fluid analysis. “We went to Vulcan Materials in California to hold an hour-long training session to inform their plant managers and maintenance personnel on our fluid,” DiGiacomo says. “We show them how to track the life of the fluid, made recommendations based on their past history, and explained how to get the best life out of the fluid.”

Minimizing Oxidation

Heavy fluid oxidation occurs when supplies of fresh air come into contact with hot heat-transfer fluid and convert fluid molecules to organic acids. As a result, the fluid becomes thicker, darker and more odorous, and its heat-transfer capabilities drop dramatically. “On average, fluid will last five to seven years,” DiGiacomo adds. “The exact life in any specific circumstance will vary depending on so many variables. With our new antioxidant additive product, we are expecting to extend that operating life when testing shows significant oxidation.”

The company’s newest product, the Paratherm AP (antioxidant protection) is not a heat transfer fluid. This is an aftermarket additive that stops sludge formation caused by acids that develop in existing thermal oil. The product restores oxidation resistance and extends service life. “The biggest challenge with heaters and fluid, especially in asphalt plants, is oxidation,” DiGiacomo says. “Our new product can reduce the oxidation level in the fluid so it will extend the working life of the fluid in the heat process.”

Paratherm attended the World of Asphalt 2015 tradeshow in March where it was able to showcase its industry-leading heat-transfer fluids for asphalt tanks, mix plants and storage silos. It also introduced its innovative new additive product, which is specifically designed for asphalt heating applications.

Moving forward, Paratherm’s long-term goal is to focus more on the asphalt market while continuing to expand into new industries. “As more roads are being repaired and infrastructure continues to build up, asphalt is not going anywhere in the future,” DiGiacomo says. “We’ve found that more and more asphalt plant managers recognize the value of reducing downtime and proactively maintaining their heating systems. It’s a good focus.”