Duininck celebrates 100 years with newly commissioned portable counterflow plant in Texas

In 2024, Duininck commissioned a new 350-ton-per-hour (TPH) portable counterflow asphalt plant in Texas—their first of its kind. For most contractors, a new plant build is about efficiency, mobility, or production capacity. For Duininck, it was all of that—and a return to a partnership grounded in trust, flexibility, and shared values built over more than 30 years.

Editor’s Note: Duininck was founded in 1926 when three entrepreneurial brothers started a road construction business in Prinsburg, Minnesota. In keeping with AsphaltPro’s anniversary celebrations this year, we wish the Duininck team a Happy Centennial!

History of an Industry Relationship

The relationship between Duininck and CWMF traces back to the early 1990s, when a problematic baghouse order from another vendor brought together Harris Duininck, second generation owner, and Loren Mick, founder of CWMF. Loren stepped in to help resolve the issue, and sparked a working relationship built on service, accountability, and mutual respect.

Travis Mick, vice president at CWMF, remembers those early days clearly. “Harris and my dad were like oil and water at first—very different personalities—but somehow it worked. They ended up building a real friendship grounded in respect, even if they didn’t always agree.”

Even after Loren’s passing, the personal connection remained. “Harris stayed in touch and shared stories about the two of them working together,” Travis added. “That kind of legacy says a lot, not just about companies, but about people.”

Duininck’s Texas roots go back to 1985, when challenging business conditions in Minnesota prompted expansion south.

Chris Duininck, president of Duininck Minnesota, has watched that trust carry forward. “What started between Harris and Loren evolved naturally as both companies grew,” Chris said. “As we matured, the partnership carried through to our teams at every level.”

In 1999, Duininck commissioned CWMF to build a complete asphalt plant from the ground up, which was an experience that set the tone for future collaboration.

Growing Across State Lines

Duininck’s Texas roots go back to 1985, when challenging business conditions in Minnesota prompted expansion south. Fifty families relocated from Prinsburg, Minnesota, helping launch the Texas division, while Harris Duininck remained in Minnesota guiding diversification and growth at home.

Timeline Snapshot

1985: Duininck launched its Texas division and 50 families relocated from Prinsburg, Minnesota

2024: The new portable counterflow plant was commissioned in Texas

Today, Duininck operates asphalt plants in both regions, shifting crews as seasons change and investing in equipment that supports large-scale, geographically dispersed projects. For Texas, flexibility was critical, and Duininck selected a 350-TPH portable counterflow plant to support its Texas operations in the early 2020s. It was commissioned in 2024. (See sidebar for details.)

“With a market defined by long haul distances and decentralized projects, mobility matters,” Chris explained. “A portable plant allows us to bring production closer to major highway and municipal work, reducing transport time, fuel use, and cost—without compromising quality.”

The 350-TPH counterflow system delivers the output required for major infrastructure projects while maintaining tight temperature control and efficient fuel use, which are key factors in Texas’ high-heat paving environment.

“Our experience led us to partner with CWMF to build a plant suited to our needs,” Chris added. “The last complete plant we purchased was more than 20 years ago, and the timing was right to deploy additional resources in the market.”

After three decades, the partnership operates without complexity.

“A lot of our deals have been done on a handshake,” Chris said. “It all comes down to trust—trusting each other to get the job done and meet commitments.”

From CWMF’s perspective, that familiarity leads to better solutions. “When you know a customer this well, you understand what matters most to them,” Travis said. “That allows us to recommend equipment and configurations that truly support how they work.”

Both companies point to people as the foundation of quality work.

“Our employees take pride in their workmanship and in representing the company well,” Chris said. “There’s real satisfaction in supporting a family business and recommending them across the industry with confidence.”

“That connection matters,” Travis added. “People work harder for people they trust, and that’s been true at every level of this partnership.”

CWMF, now a legacy brand within Astec, reinforces the long-term strength of customer relationships like Duininck’s, providing scale and stability behind the products and values that have earned trust over decades.

More than 30 years in, the Duininck–CWMF relationship isn’t just about equipment. It’s about consistency, accountability, and building for the long haul, one plant at a time.

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Why Duininck Chose a Portable Counterflow Plant for Texas Operations

Plant Type: 350 TPH Portable Counterflow Asphalt Plant

Location: Texas

Built By: CWMF

Commissioned: 2024

Duininck selected a 350-TPH portable asphalt plant to support Texas operations defined by long haul distances and decentralized job sites. Mobility allows production to move closer to large highway and municipal projects, reducing transport time, fuel consumption, and overall cost while maintaining consistent mix quality.

Counterflow technology was the preferred choice due to its ability to meet both performance and environmental expectations. By moving aggregates opposite the exhaust stream, the system is designed to maximize heat transfer, improve fuel efficiency, deliver tight temperature control, and reduce emissions, which management saw as critical advantages in high-temperature paving environments.

The system supports Duininck’s production target of 350 TPH, aligning with the scale of heavy civil and municipal work common across Texas. Its ability to integrate high volumes of recycled asphalt pavement (RAP) also supports sustainability goals while lowering material costs.

Mix Design: Minnesota vs. Texas

Minnesota

• Focus on freeze-thaw durability
• Softer binders (PG58-34)
• Higher recycled content
• Rounded glacial aggregates
• Emphasis on crack resistance and long-life pavement

Texas

• Built for extreme heat and heavy truck traffic
• Stiffer binders (PG70-28/PG76-28)
• Angular limestone and granite aggregates
• Dense-graded structures for rut resistance

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Shared Direction, Sustainability

Both regions are expanding balanced mix design (BMD) programs, blending volumetric targets with performance-based testing to meet durability expectations across climates.

Duininck’s operational and sustainability strategy centers on smart material management—locating plants near job sites, sourcing aggregates locally, and reclaiming and recycling asphalt whenever possible. Recent projects, such as reprocessing materials at Willmar High School, have demonstrated both environmental benefits and meaningful cost savings.

Editor’s Note: The Focus on Performance series from AsphaltPro Magazine allows OEMs and service providers in the industry to highlight asphalt professionals who have improved efficiencies and the bottom line through best practices and performance. This month’s installment, featuring a producer in the Northeast, dives specifically into efficiencies gained through a burner retrofit.

When a Maryland producer was looking to upgrade their dated burner system to improve reliability and energy efficiency, Detroit Stoker Company, Monroe, Michigan, responded with a HADES burner and HBC burner control system.

The customer operates a 400 tph, dual drum plant, which includes a counterflow dryer and separate mixing drum. The burner replaced a dated 100 MBtu/hr sealed in burner, which had proven to be difficult to service and maintain. Detroit Stoker with partner, Meeker Equipment Company LLC, Belleville, Pennsylvania, provided a new HADES-100 (100MBtu/hr) dual fuel burner capable of firing natural gas (primary fuel source) with No. 2 and/or recycled fuel oil backup fuel.

The original burner system included:

1. Direct drive fan with 1,800 rpm 100-Hp motor.
2. Single control actuator with linkages driving a fan outlet damper (airflow control) and fuel control valve(s) for gas and fuel oil.

Sustainability Tips for Asphalt Plant Dryer Burners

The new burner system features include:

1. A direct drive, 1,800-rpm fan; however, due to the energy efficient design of the burner, only a 60-Hp motor was required to achieve the same burner rated capacity. In addition, a variable frequency drive (VFD) is now used for precise combustion air flow control via the HBC panel.
2. Independent (gas and fuel oil) direct coupled fuel actuators controlled by the HBC panel.
3. More compact footprint/package as a result of smaller combustion air fan and reduction in ancillary dampers/drives/linkages. This improved design results in higher reliability and maintainability.

These features offer numerous advantages, such as precise combustion air/fuel ratio control across the entire burner input range (low to high fire). This means maximum fuel efficiency can be achieved regardless of plant production rate.

Additional benefits include enhanced safety as the HBC panel is continuously monitoring both air and fuel demand versus feedback and “cross-limiting” the air/fuel ratio such that the burner cannot go rich. In a linkage-based system, when the linkage slips or fails, the burner can literally be firing at any ratio, and the writer has seen burners firing in extremely rich and potentially explosive conditions as a result.

VFD savings are well documented. The motor horsepower is proportional to the speed cubed, resulting in significant energy savings by adjusting the motor’s speed to match the required load, instead of running at full speed constantly. A small speed reduction results in large energy savings. VFDs also improve efficiency with a better power factor and can extend motor life by reducing startup current.

What You Need to Know About Burner Size and Performance

Final tuned CO emissions were well under 200 ppm corrected to 7% O2 dry across multiple firing rates. Burner tuning is not only much more precise but far easier to accomplish with the use of fully characterizable air/fuel tuning curves in a burner control panel like the HBC. Tuning is accomplished with the simple change of combustion air VFD speed and/or the fuel valve(s) position electronically with the push of a button. This is of course accomplished while monitoring emissions, burner and overall plant performance.

This burner retrofit provides the producer with a future-proof, energy-efficient combustion system designed for decades of reliable operation. By replacing an outdated, maintenance-intensive burner with the HADES-100 and HBC control platform, the plant now benefits from significantly reduced electrical energy consumption, precise and repeatable air/fuel ratio control, lower emissions, and a streamlined mechanical design with fewer wear components.

The VFD, independent fuel actuators, and modern cross-limiting combustion logic all contribute to sustained fuel savings, extended equipment life, and enhanced operational safety. Together, these improvements ensure that the plant will continue to operate at peak efficiency with lower operating costs and reduced environmental impact—delivering long-term sustainability for both production and energy management.

HMA plant start-up tips for the 2026 season

To keep the hot-mix asphalt (HMA) plant in top operating condition, it’s important not to rush or skip start-up steps. Here’s a quick guide to supplement the longer pre-check article found in the January issue and to walk your team through getting your asphalt plant running properly for a profitable summer.

First and foremost, think safety. It’s easy to get complacent after a long hiatus. Refresh yourself and your team on safety procedures before getting back to work.

Take the time for a thorough inspection. Visually inspect the components, looking for worn cables, broken water lines, damaged refractory tubes, and loose or missing shields. Work your way through the plant, checking for anything that’s worn, damaged, loose or missing after it’s been sitting idle during the winter:

• Start with the drive belts, looking for frayed spots and cracks, as well as checking the tension and alignment. Ensure it matches the owner’s manual.
• Then move to the sheaves, checking for cracks, chips or broken edges.
• Also look over the conveyor belts to ensure there’s no stretching, cuts or excessive wear. Also check that the drive pulley’s lagging is intact.

Change the oils. If you didn’t change oil in all of the gearboxes when shutting down at the end of 2025’s season, do that now. Pay attention to any signs of water or metal shavings, which indicate damage. Also replace the air compressor crankcase oil and any airline oils.

Keep all the parts moving with some testing. When moving parts don’t do what they should, the whole operation will suffer:

• Test the venturi gates, watching that they close completely.
• Check the spray nozzles and, if they’re clogged or broken, clean or replace them.
• Run through all of the gates, as well, ensuring correct operation for the silo gates, cold feed bin gates, gob hopper gates and drag conveyor bypass gates.
• Test the limit switch paddles and then move on to the controls, making sure the indicators and switches all operate properly.

Also check the alignment of the plant frame. If necessary, level it to ensure the least amount of trunnion wear.

Finally, know when to call a professional for assistance. Have a qualified service tech come in to tune the burner. This is something you want to do at least once, if not twice a year, as routine maintenance.

Mike Devine is the president of ADM FAYAT Group. For more information, please visit https://www.admasphaltplants.com/ex-series/

Get your winter plant upgrades and spring pre-check list to increase 2026’s production success

January is the right time of year for most North American asphalt producers to handle updates and upgrades at the hot-mix asphalt (HMA) plant. Maintenance activities that were too cumbersome to schedule during the height of construction season when a shutdown would mean a costly delay to production can be executed now.

Five original equipment manufacturers (OEMs) and plant service providers took time prior to seasonal shutdown to offer their top tips for making the most of your winter schedule. Starting with ideas for upgrading to enhance your 2026 production, these gentlemen offer non-branded advice you could implement before season startup. They also dive into the top maintenance issues you should be watching out for in today’s asphalt mix production climate.

“A plant dry run not only verifies equipment’s operational capacity but gives a team a baseline for typical plant noises and vibrations they can expect during operation. This gives the team a head start on keying in on new noises or smells that may indicate looming issues.”—Ted Hope

The 2026 Pre-Checklist for Your Plant

Check and Control the Burner

More than one source wanted to remind asphalt professionals of the burner at the heart of your HMA plant. Terry Elbert of Commercial Asphalt Plant Services, Minneapolis, Minnesota, suggested inspecting and performing maintenance on the burners prior to spring startup.

“Both the hot oil heater burner and rotary dryer burner have fans that suck in dust throughout the year,” Elbert said. “This dust can collect in and on areas such as impellers, dampers, pressure switches and lines, pilot valves, ignitors, and scanners. Buildup of debris on dampers can affect air-fuel ratios, resulting in inefficiency. Buildup on impellers can cause balance issues, resulting in premature bearing failure. Buildup of debris in pressure switch lines, ignitors and pilot valves/plumbing can result in the dreaded misfire. Just a little cleaning in these areas can save you a lot of trouble later.

“It is also a good idea to test burner safeties at this time,” he continued. He cautioned that some burners in the field might have safety switches that have failed or weren’t wired or adjusted properly.

Make Plans for Plant Maintenance this Winter

But don’t stop there. “While you’re at it, have your combustion gases analyzed. This will tell you if you are burning efficiently throughout the firing range. Sometimes small air-fuel adjustments can result in big savings.”

Ron Heap, the president of Tarmac International, Inc., Kansas City, Missouri, spoke of investing in burner control technology for remote monitoring and troubleshooting. He started with a financial scenario.

“Let’s say mid-year, a burner goes down and the plant cannot make repairs and bring the dryer back online,” Heap theorized. “It will cost $2,000 to get a burner tech to the site and $2,000 for him to return home. If there is one day of work, that brings the cost to $6,000. Add to that the lost revenue from being down. My suggestion is to invest in a burner control that allows the operator to see the instrument limit stream that caused the failure and allow a serviceman to get online and see the burner, negative pressure at the burner faceplate, and the ID fan function. 90% of the onsite service calls can now be via a phone call and an internet connection to the burner control.”

Iván Fernández Hevia, international sales director of Intrame, Valladolid, Spain, also highlighted the importance of investing in various controls, stating this will depend heavily on the specific plant being evaluated.

“Generally speaking, for an older plant, I would suggest upgrading the controls and automation systems, including a full set of sensors,” Fernández Hevia shared. “This allows operators to monitor and control every parameter, generate comprehensive reports, and ultimately reduce operating costs while detecting potential failures in advance.”

Does it snow on your plant? “For customers in cold regions with snow during the winter such as Greenland, Switzerland, United States and Poland, we usually recommend covering all the motors, allowing ventilation,” Intrame’s Fernández Hevia shared. “When snow slowly melts, moisture can get inside and damage the motors, so this helps prevent that.”

How Lubrication Strategies Cut Costs at the Plant

Analyze the Parts

“Each year it is required that a NFPA® (National Fire Protection Association) test be performed on the burner and the fuel train,” Heap said. “This can check the double block valves for leaks, which can reduce the risk of an explosion if both stay open when they should be closed. The review will also point out other instruments that have failed. Finally, the burner can be tuned for lower CO which saves money on fuel and reduces emissions of CO to the atmosphere.”

Michael Petrie, the president of Motion Engineering, Caledonia, Wisconsin, also addressed analyzing the burner’s efficiency prior to season startup.

“I recommend firing up the burner, lighting it, and cycling it up and down while making some test mix if possible,” Petrie shared. “Be sure to use an analyzer during this process as it is the only way to confirm proper fuel efficiency and reliable burner performance. Running test mix helps confirm that every component is ready for a smooth, productive asphalt season.”

Winter Asphalt Plant Greasing: What to Know and Avoid

The team at Astec Industries, Chattanooga, Tennessee, agreed with the importance of using an analyzer to double-check burner and fuel efficiency. They also recommended the use of another type of analyzer all over the plant. Ted Hope, the director of service at Astec, suggested plant personnel perform a thermographic electrical inspection.

“A thermographic electrical inspection helps reveal electrical issues with the equipment such as: Loose connections, which can be from installation, overtime due to vibrations, or even thermal cycling; undersized components; and failing or damaged breakers and starters. These catches early in the season can help avoid costly downtime and last-minute repairs. A thermographic electrical inspection can be done with just the equipment running but will reveal the best results under a load.

“The start of a season would be a great time to do an inspection,” Hope continued. “These inspections can help operators across all regions and plant sizes find and repair issues before they create downtime. It is always less costly to do the repairs on your schedule than the equipment’s.”

Get Clean Production Next Season

The inspection isn’t something your plant personnel will necessarily do on their own. Hope explained: “A thermographic electrical inspection requires an infrared thermal camera (major brands being FLIR or Fluke), but the inspection is almost always sold as a service. The reason for this is due to certifications and training the inspector must have to provide an adequate report and results. There are many providers across the world that provide this service.”

Along with investing in a thermographic electrical inspection, plant personnel should consider investing in an inline flow meter on the main gas line to track fuel consumption.

Petrie suggested this technology “provides precise tracking of fuel consumption, which is critical for optimizing plant efficiency. As the industry moves toward transparency and accountability of a plant’s carbon footprint, accurate tracking will likely at some point no longer be optional. This technology is one way to start collecting meaningful data to understand how your asphalt plant is performing to benchmark energy use. I think that in time, regulatory agencies will require documentation of fuel consumption per ton of asphalt produced. Adopting this technology early would allow for a strategic advantage.”

Get Strategic

Elbert suggested another technology that can add a strategic advantage as we head into 2026.

“As far as adding a new technology, my first choice as an operator would be license plate identification for trucks coming onto the scale,” Elbert said. “Information for that truck can be saved and auto populated on the scale ticket. This may not make sense for a smaller operation that utilizes the same small group of trucks but, for a larger operation selling multiple mix types to multiple customers, this can free up unnecessary CB chatter, reduce ticket errors and save data entry time. Any technology that allows your operator more time to focus on the plant will pay dividends.”

It will also pay dividends to run some strategic tests during the off season when performing maintenance doesn’t require an interruption in production.

“Run a rotational test on veiling,” Heap suggested. “Here you would run a plug of material into the drying section and watch the veil as it moves through the drying zone. Misadjusted drying flights can be easily seen, and a movie taken with a phone. Doing [such testing] improves safety and reduces dollars spent.”

Mix-and-Match Asphalt Plants

“Complete a dry run before starting up,” Astec’s team suggested.  “A trial run of the equipment can give the team on site time to test all the motors, belts and rotating steel—all before it is used to make asphalt. A plant dry run not only verifies equipment’s operational capacity but gives a team a baseline for typical plant noises and vibrations they can expect during operation. This gives the team a head start on keying in on new noises or smells that may indicate looming issues.”

Petrie recommended getting the tank farm hot and circulating liquid asphalt cement (AC) throughout the system.

“Circulation of the hot oil system is paramount to ensure that the meter pump is functioning properly and that there is proper flow without restriction in the system,” Petrie said. “It is important to check that valves and pumps are working properly and there are no blockages throughout the system. If this is not checked, it could lead to a multitude of problems including changing out valves and pumps, replacing or cleaning strainers, flow problems, and leaks.”

“This technology is one way to start collecting meaningful data to understand how your asphalt plant is performing to benchmark energy use.”—Michael Petrie

Back to Basics

Along with the guidance offered here, don’t forget the foundational concepts of good plant operation. If your plant has been running for a few years, the winter downtime is the right time to get back to basics with maintenance and inspection.

“I would encourage them to inspect the entire plant for buildup,” Elbert said. “Inspect the baghouse for buildup. Baghouses tend to condensate more at the end of the season as temperatures drop; this can lead to ‘mudding’ on the baghouse walls or on the auger grates if you have them. You will want to clean this so it doesn’t continue to build.

“Inspect the ductwork between the dryer and baghouse,” he continued. “Oftentimes, dust can settle out and build up in the bottom of the ductwork. This causes higher velocity and premature wear. Clean or chisel the recycle scoops and the drum mixing area. Check the silos. Buildup on the cones will not go away when you put hot mix on top of it; it will only continue to grow. Start the season out free of buildup throughout your plant.”

Top Plant Fixes to Plan for Winter Downtime

Hope also spoke of general housekeeping. “A clean and organized plant site greatly enhances the chance of catching issues before they turn into lost production time,” he shared. “Clean equipment can show leaks potentially long before the seal or bearing completely fails. This gives the plant personnel time to get the item replaced before its inevitable failure. This extends well beyond mechanical as a clean electrical cabinet or panel is not only safer but prevents potential issues caused by dust and greatly decreases troubleshooting time if an issue arises.”

By using this winter’s downtime to install meaningful upgrades and prepare your pre-startup checklist, you’re strategically planning for a prosperous 2026 and guarding against unpleasant surprises in the spring. At the end of the winter day, the guidance and ideas mentioned above are the top tips to help enhance your bottom line.

Resources for More Information

The original equipment manufacturers (OEMs) and service providers who responded to questions for this article took time to share their expertise with the readers of AsphaltPro and provided excellent information. To address additional questions you might have, reach out to them, or your specific OEM, directly.

Astec Industries

Ted Hope

thope@astecindustries.com

Office (423) 827-1591

Commercial Asphalt Plant Services

Terry Elbert

Terry@caplantservices.com

Office (763) 910-0051

Intrame

Iván Fernández Hevia

ivan.fernandez@intrame.com

Office (954) 865-9627

Motion Engineering

Michael Petrie

Mike@motionengineering.net

Office (414) 510-6097

Tarmac International

Ron Heap

Rheap@tarmacinc.com

Office (816) 220-0700

Editor’s Note: The Focus on Performance series from AsphaltPro Magazine allows OEMs and service providers to highlight professionals in the industry who have improved efficiencies and the bottom line through best practices and performance. This month’s installment features a case study with electric heat from Intrame.

This article explores the transition from traditional oil heating to electric heating systems for asphalt storage. With increasing focus on emissions reduction, energy efficiency and sustainability, electric heating offers operational and environmental advantages. Through technical analysis and real-world data, we evaluate the energy demands of maintaining asphalt temperature and compare the economic and environmental implications of both heating methods.

Of course, the data and figures presented in this article are intended to provide a general overview and to stimulate reflection on the potential benefits of transitioning to electric heating. They are based on typical conditions, and on theoretical calculations. However, actual values may vary significantly depending on many factors such as equipment design, meteorological conditions, electrical grid capacity, energy prices, fuels compositions, etc.

Asphalt plants are continuously evolving to reduce environmental impacts and increase efficiency. Some key development areas include:

• Reduction of pollutant emissions
• Increased use of recycled materials in asphalt mixes
• Lower productions and storage temperatures
• Improving production energy efficiency per ton of hot-mix asphalt

Increasing efficiency by reducing the energy required to produce each ton of hot mix offers the two main benefits of lower operational costs and reduced pollutant emissions and carbon footprint. This results in greener, more environmentally friendly and sustainable asphalt plants.

One approach to achieve these goals is to use electrical heating instead of oil heating. Throughout this article, we will explore how electric heating can be one of the answers to reducing both costs and emissions.

Electrify Asphalt Plant Heat Efficiency

A Case Study

This study is complex due to the numerous variables affecting the results. Some of these variables are the type and size of tanks, type and thickness of the thermal insulation, type and thickness of the tank cover/skin, filling level, medium ambient temperatures, average winds and storage temperature, among others.

As an initial approach to the energy required to maintain the temperature of liquid asphalt cement (AC) inside a tank, over a 24-hour period, we will use some heat transfer calculations, applied to a standard Intrame electrically heated tank, under the following conditions:

• Storage temperature of the liquid AC: 320ºF (160ºC)
• Tank capacity: 16,000 gallons (60m3)
• Tank filling level: 75% = 12,000 gallons (45m3)
• Liquid AC density: 60 lbs/ft3 (960kg/m3)
• Specific heat of the liquid AC: 0.501 BTU/Lb·ºF / 2.098 kJ/kg·ºK
• Average wind speed: 10 ft/s (6.82 MPH)
• Ambient Temperature: 50ºF

Meeker Spotlights Electric Heater & UL‑142 Tanks at World of Asphalt

Insulation:

• Material: mineral wool
• Thermic conductivity at 320ºF: 0.061W/(m·K)
• Thickness: 8 inches

External cover/skin:

• Material: aluminum
• Surface emissivity coefficient: 0.05
• Thickness: 1.2 mm

The theoretical energy required to maintain 12,000 gallons of liquid AC, at 320ºF, inside the tank, over 24 hours, under these conditions, using convection, conduction and radiation calculations, is approximately 200 kWh, which equals 16.7 Wh/gallon/day.

We have also remotely monitored the temperature drop of several tanks, when disconnecting the heating over a 24-hour period, at different times of the year, with different inside and outside temperatures and winds.

Process Heating Company Designs Lo-Density® Hot Oil for Auto Control, Even Temp

The first intuitive conclusions are:

• The fuller the tank, the slower temperature drop it has. An almost empty tank can lose temperature at a rate more than double that of a full tank.
• The hotter the AC is in the tanks, the faster it loses temperature.

After some field data analysis, we found an average temperature decrease in summer, from 11ºF to 14ºF per day, and from 14ºF to 18ºF per day in winter, when heating is disconnected at 320ºF.

With this information, we can calculate the energy required to maintain the temperature of the AC inside a tank, for a 24-hour period. This will be done using the most common tank size in Europe, which is 16,000 gallons (60m3), filled to ¾ capacity (12,000 gallons):

Assuming a total heating efficiency of 80% for the hot oil system, and 90% for the electric heating, the approximate energy output required for keeping the temperature in the tank at 320ºF is:

Hot oil system: 264 kWh = 22 Wh/gal

Electric system: 234 kWh = 19.5 Wh/gal

Please note that the figures above refer to 8-inch mineral wool insulated tanks. Electrically heated tanks are insulated with a minimum of 8 inches or even 12 inches of mineral wool, reducing thermal losses considerably.

According to EPA’s 2020 grid emission factors, CO₂ emissions of U.S. power generation grid are 0.818 lbs/kWh. Therefore, maintaining 12,000 gallons of liquid AC, at 320ºF for 24 hours using electric heating, will require an energy of 234 kWh, and will generate approximately 0.096 tons of CO₂/day.

Referencing the cost of the electrical energy according to the U.S. Energy Information Administration (EIA), the average cost in 2024 was $0.0844/kWh. Utilizing this cost factor, the cost of the electrical energy needed to maintain the temperature of the AC inside the tank at 320ºF is:

Depending on the geographical location and solar radiation availability, this cost may be further reduced by partially powering the electric heating system through photovoltaic energy, which also contributes to lowering overall emissions.

We have also collected field data from different plants, operating under diverse weather conditions, various tank specifications and AC types.

Based on this information, the average No.2 diesel oil consumption required to maintain the AC at target storage temperature is approximately 0.003 gallons of diesel per gallon of AC per day. Assuming an average fuel cost of $2.50 per gallon, this results in a daily heating cost of $0.0075 per gallon of AC, significantly higher than $0.0017 per gallon per day associated with electric heating.

In terms of emissions, maintaining the temperature of 12,000 gallons of AC using a hot oil heater would require burning: 0.003 x 12,000 = 36 gallons/day, which will emit 0.41 tons of CO₂/day, further reinforcing the environmental benefits of electric heating solutions.

In addition to the figures above, burning fuel to heat oil has other associated costs and disadvantages that should be considered, such as oil changes and scheduled emissions testing. In some countries, a 24-hour custodian is required to ensure safe operation of hot oil systems. This norm is gaining ground in more and more countries as the emphasis on safety and lowering insurance costs becomes more predominant worldwide. In these cases, an auto-shutdown feature is required. An assigned custodian must go to the heater and inspect to be sure everything is operating properly, then press a reset button before the allotted time in order to keep the system running.

Hot oil heaters are reliable and essential for multiple applications, and they have served the industry for decades. However, with growing emphasis on sustainability and cost control, electric heating is gaining ground. In countries like France, Spain, the United Kingdom and Poland, nearly 100% of all new asphalt plants are equipped with electric heating.

Electric heating of AC storage tanks represents a forward-looking solution for the asphalt production industry. It offers a compelling combination of economic savings, operational simplicity and environmental responsibility. As energy prices and emissions regulations continue to evolve, the adoption of electric heating systems will likely become the new standard across global markets.

Iván Fernández Hevia is the international director at Intrame, managing operations across nearly 50 countries. He brings deep expertise in navigating the technical and regulatory specifications of diverse markets.

Editor’s Note: The Focus on Performance series from AsphaltPro Magazine allows OEMs and service providers to highlight professionals in the industry who have improved efficiencies and the bottom line through best practices and performance. This month’s installment from Motion Engineering, Inc., focuses on plant maintenance strategies during the off season.

When the last ton of mix goes out the gate for the paving season, it’s tempting to close shop and call it a season well done. But for the forward-thinking asphalt producer, winter isn’t downtime. It’s go-time for planning, inspecting and maintaining the critical equipment that keeps production rolling the other nine months of the year. Asphalt plants are complex systems of mechanical, electrical and combustion equipment—each with their own wear patterns, failure points and maintenance needs.

Many of the failures we see in peak season—burner malfunctions, seized valves, worn-out drag slats, failed sensors—are entirely preventable. The culprit is often deferred maintenance and a lack of thorough winter inspections.

When you fail to inspect and maintain during the off-season, you’re rolling the dice on everything from your drum bearings and flighting to your silo gates and burner systems. In most cases, early detection means a simple repair; ignored, it becomes a catastrophic failure.

“What I continue to see out in the field is that we are nearing a time when a significant number of plant operators who have extensive experience are retiring.”—Michael Petrie

Winter is the perfect storm for hidden damage as moisture intrusion causes rust and electrical issues. Also, thermal cycling can cause stress cracks and reduce the strength of welds. As with all mechanical equipment, periods of inactivity can result in seizing, corrosion or undetected mechanical failure.

At Motion Engineering, Inc., we’ve been in the guts of hundreds of plants, and we’ve seen what works, what breaks and what costs producers serious money. If you’re wondering what you should inspect this winter, here’s your prioritized guide, system by system, with insider tips on what to look for and how to address potential issues before they turn into operational nightmares.

Top Plant Fixes to Plan for Winter Downtime

Drum/Dryer System

I have personally seen entire drum sections separate from excessive wear and lack of proper inspection. With a new drum costing upwards of $1 million, it is critical to extend the life of your current drum by properly inspecting it and completing the necessary repairs.

Here are the key areas that you should be evaluating once production stops for the season.

• Drum shell and tire wear: Look for excessive scarring, pitting or ovality. Uneven wear on tires or trunnion surfaces often indicates misalignment. It’s also important to inspect the thickness of the drum shell looking for cracks and separation.
• Flighting: Check for broken or severely worn flights that affect aggregate veil and drying efficiency. Check for worn out hardware.
• Trunnion rollers and bearings: Look for flat spots, vibration, excessive noise and leaking seals.
• Gearboxes: Check all gearboxes for oil leaks or unusual noises that may indicate failure.
• Thrust rollers: Inspect for proper positioning and contact pressure.

What to Do:

• Realign the drum if there’s abnormal wear.
• Install replacement liners if thickness testing comes back at a level reaching anything less than ¾ of the manufacturer’s original thickness.
• Replace broken or worn flighting to maintain proper drying.
• Grease and test roller bearings. If they’re noisy or have play, replace them before failure occurs.

Drag Slat Conveyor Checklist for Winter Maintenance

Burner System

As a distributor for multiple combustion manufacturers, I have witnessed the catastrophic failures and the impact they have on producers when these systems fail at the most crucial of times. Particularly when spring hits and the first batch of mix is on the schedule, the last thing you need is a burner malfunction.

Just this past spring, I had a customer that waited until their first job to fire up their burner only to realize the control system was having intermittent failure that would not allow them to run. This cost them unprecedented downtime and hundreds of thousands of dollars to try to diagnose and correct the problem. A simple test run earlier in the season could have prevented this from occurring.

Here are things to inspect on your test run.

• Combustion zone and flame shape: Look for evidence of soot, poor combustion or flame impingement.
• Blower motors and controls: Check the amperage draw, noise and contactor condition.
• Fuel lines and filters: Inspect for leaks, clogs or degradation.
• Ignition systems: Check spark plug condition, transformer performance and timing controls.

What to Do:

• Clean and calibrate the burner. A proper tune-up can significantly improve fuel efficiency and reduce emissions.
• Replace any aging or cracked fuel hoses.
• Make sure all safety components are working properly: Pressure switches, safety shut-off valves, flame supervision and limit switches.
• Schedule an inspection for the fuel filtration system.
• Make sure your burner management system is functioning properly. It’s not enough just to turn it on. You need to make a test batch and ensure your burner ramps up and down properly.

Quick Tips for Wintering Equipment

Electrical and Control Systems

Any electrical or control failure at your plant is a sure guarantee of downtime at your facility. It is critical to ensure the functionality of all the equipment prior to your first scheduled job for the season. I have witnessed countless occurrences where producers have encountered electrical issues due to corrosion or water intrusion and simple weather proofing during the downtime could have prevented those issues.

Here is what I recommend inspecting and preparing for in the off season.

• Wiring and junction boxes: Look for water intrusion, corrosion and loose connections.
• Sensors and thermocouples: Test signal consistency and placement accuracy.
• Control panels and PLCs: Update software, test relays and backup settings.

What to Do:

• Replace compromised wiring and weatherproof enclosures.
• Calibrate all critical sensors.
• Perform a full system simulation before startup season.
• Have a backup CPU with your burner control program loaded.

9 Tips for Asphalt Plant Maintenance

Baghouse & Dust Collection

Lack of proper maintenance on dust collection systems can lead to decreased efficiency, increased operating costs as well as safety hazards for your employees. The last thing you need is for a fire to start because of lack of inspecting your baghouse bags. Clogged or damaged filters are a primary cause of environmental issues and higher energy costs.

Here is what I recommend inspecting once your team winds down production for the season.

• Filter bags: Check for holes, abrasion or oil contamination.
• Dampers and ductwork: Ensure smooth operation and check for buildup or corrosion.
• Pulse valves: Listen for consistent operation and monitor differential pressure.

What to Do:

• Replace damaged or blinded bags. Dust carryover leads to environmental issues and reduced efficiency.
• Clean ducting and realign dampers.
• Replace worn diaphragm valves for consistent pulse cleaning.

Neutralize Odors at Your Asphalt Plant’s Stack and Baghouse

Drag Conveyor & Silo System

One of the primary areas of expertise for Motion Engineering, Inc., is the installation of silo liners. Whether they are ceramic or steel liners, proper installation of these liners will extend the life of the equipment for many years. Also, there are safety concerns if structural integrity is not sound. I’ve seen the silo tub wall settle or “beer can” on numerous plants over the years due to neglect.

I recommend inspecting these critical areas on the Drag Conveyor/Silo System.

• Slat chains and sprockets: Check for elongation, cracked links and worn teeth.
• Floor liners and troughs: Inspect for excessive wear, warping or holes.
• Discharge gates and cylinders: Look for leaks, delayed action or bent rods.
• Batcher Gates: Make sure batcher gates are operating properly. A batcher stuck open can allow a hole to wear right through the tub wall.
• Silo Thickness: Check the thickness of the cone and tub wall to ensure structural integrity.

What to Do:

• Measure chain stretch and replace if beyond spec (usually 2–3% elongation).
• Weld or replace worn liners—holes become heat loss zones and safety risks.
• Rebuild or replace gate actuators that fail under load.
• Use a thickness tester to properly map the cone and up the tub walls to ensure structural integrity as well as identify if liners are needed.
• Properly install ceramic or steel liners on any silo cones/tub walls that have a thickness of < ¾ of the original manufacturer’s thickness.

Keep Silo Maintenance Safety a Top Priority

Asphalt Tank & Pump Systems

When it comes to annual maintenance, it’s important not to overlook your tank farm system.  Just this year at three different asphalt plants, our service team removed and replaced liquid asphalt cement (AC) pipes due to restricted flow. After inspection, we identified that the pipes were clogged due to buildup that had been overlooked. This caused supply and return issues as well as offload issues.

Here are a few key areas to be focused on when it comes to inspection and repair for your tank farm system.

• Circulating pumps: Check for seal leaks, bearing play and pump performance.
• Heaters and lines: Inspect lines for coking and buildup. The most vulnerable lines are the AC lines that oil sits in for long periods of time. Make sure you understand what the max flow of your pump is. When you know that, you will know when your lines are starting to clog.
• Valves: Ensure valves are operating correctly and identify any valve stem leaks or seal leaks.

What to Do:

• Rebuild pumps if bearings or seals are suspect.
• Flush lines and test heater operation at full temperature. Repair and replace any pipes where flow is restricted.
• Repair and replace any valve leaks.
• Insulate exposed lines to prevent cold-weather failures.

Do Your AC Tank Inspection Procedures Pass the Test?

What I continue to see out in the field is that we are nearing a time when a significant number of plant operators who have extensive experience are retiring. Less experienced plant operators are taking over those roles and they lack the proper knowledge of what to look for. This is causing problems for producers. Your team might be capable, but winter inspections are the time for precision, not assumptions. Hiring experienced maintenance professionals to assist ensures your plant is not only inspected thoroughly, but also that small issues are corrected before they snowball.

Michael Petrie is the president of Motion Engineering, Inc.