Producers need to take advantage of winter downtime to get asphalt plants in optimum condition for season startup—that’s a given. Let’s dive right into modern ideas. The manufacturers who visit plant sites and place the orders all year long took some time to share what’s hot among your peers for updating the facility and improving the bottom line.
Ron Heap of Tarmac International Inc., Kansas City, Missouri, sees producers looking for incremental production improvement of the total tons per hour or in the percentage of recycled materials in mixes. “Often this production request can be improved with efficiency in the drying section of the drum mixer with adjustable flights, or in the preparation and number of recycled products,” Heap shared.
How Much Do You Dry?
To increase production by 33 percent for a $600,000 price tag for a specific customer in the Kansas City area, Tarmac personnel focused mainly on the dryer and air moving equipment. That involved replacing the 8-foot-diameter drum with a 9-foot-diameter drum, and replacing fixed drying flights with adjustable drying flights. The mixing flights to be used in the new dryer are now self-cleaning. Heap explained you can’t expect to increase production by 33 percent without modifying your air pollution control system, too.
“Fortunately, they had an oversized baghouse to begin with,” Heap said. This saved the contractor thousands of dollars right off the bat. “The air system went from 45,000 ACFM to 55,000 ACFM. Our customer already had a VFD on the fan, and that was moved from 200 HP to 250 HP.”
Heap explained, “Other improvements include a knock-out box over the dryer to allow fines to enter the RAP collar with a gravity chute versus augers from the baghouse. The lower drum tire was moved away from the RAP collar keeping the lower tire/trunnions assembly cleaner.”
Now Tarmac’s client will have higher production to better serve early morning contractors.
Jim Grida of Reliable Asphalt Products Inc., Shelbyville, Kentucky, sees producers still going for the addition of silos, bins and tanks to get more production. It may seem a standard fallback for updates, but the reasoning remains sound. Think about the number of mix designs your facility produces in a typical week, and then think about capacity.
“Depending on the plant, more silos make it easier for the operator to run multiple mixes,” Grida shared. He’s not wrong on that point, or on the idea that more cold feed and recycle bins give the plant more flexibility.
“More and more mix designs call for five to six different blends of sand and stone, making the plant harder to switch on the fly,” Grida said. “More and more plants are running 30 percent or more RAP, and they’re needing to fractionate their RAP so their QC can fine-tune the mix design.”
Jerry Vantrease, the construction sales manager for Heatec Inc., Chattanooga, sees producers looking at additional tank storage to meet demand for more mixes and to take advantage of cheaper asphalt prices. When working with producers, he often recommends upgrading to a more efficient heater along with insulating lines, flanges and related equipment to get more efficiency at the plant.
How Efficient are You Overall?
A common thread in this guide is getting the plant to operate more efficiently. Travis Sneed with Astec Industries, Chattanooga, spelled that out. “Efficiency is always going to be one of your main concerns, even when you’re not buying new equipment. One of our jobs is to make the owner aware of what’s available that can improve his efficiency.”
Depending on your location, you’ll have more or less interest in the many tools available in the marketplace. “A plant in Florida that deals with high moisture will have a different need to ‘up’ production compared to a plant in the west where it’s dry,” Sneed said.
Sneed reminded owners to look at the overall plant site. “Does he have paved stockpiles? That cuts down on drying his materials. So it starts out as a site assessment to make sure the whole site meets his needs. Regardless of where you’re at, make sure your equipment is sized properly. Plants run more efficiently when at their top capacity. If you’re running 150 tons an hour through a 400-ton-an-hour plant, it’s not efficient.”
Clarence Richard of Clarence Richard Companies, Minnetonka, Minnesota, sees a common fix at plants at the drag slat conveyor. When he goes to a plant site to train personnel, one of the first things he recommends to increase energy efficiency is to put a VFD on the drag conveyor.
“If the plant is rated for 500 tons an hour, but they regularly run at 250, the drag is going, going, going,” Richard said. “You want to put a VFD on the drag conveyor so you can vary how fast that goes. Then you’re not wearing out your drag, or its sprockets. You save on energy draw that way. It’ll pay for itself in just a couple of projects when you’re running at 250 tons an hour.”
Lennie Loesch of Stansteel/Hotmix Parts & Service, Louisville, Kentucky, also recommends looking at the overall plant as a whole, and he brings plant efficiency in line with quality.
“Going in and doing an examination or an audit of the facility is the first step to making a recommendation,” Loesch shared. “In some cases, dramatic production increases can be made by adjusting the induced draft fan on the baghouse system or modifying the flighting in the rotary dryer. At other times, there may be more of an investment required to modify the plant to accept RAP or RAS. There are a number of other cases that may be more of an issue with product quality. If the plant has not kept up to date with technology on weighing, metering and interlocking, it may be time to look at a new control system that accurately proportions all the ingredients to make not only quality mix, but one that would receive bonus payments exactly meeting the government specification and allowing proper on-road compaction.”
Loesch pointed to Stansteel’s RAP Eater™ counterflow drum mixer. “The RAP Eater drum will provide the asphalt producer a jump two or three generations of technology by a simple change-out.” He explained that many plants are restricted on the amount of recycle material they can process, giving producers problems of plugging, short mixing zones or failing performance designs. The RAP Eater drum mixer is designed for thermal heat transfer and efficiency to run up to 50 percent recycle—and more—while maintaining the quality product mix.
“It can replace many failed designs and help the producer keep 80 percent of the infrastructure of his plant such as his silos, baghouse, material handling, etc., and get the benefits of new technology without spending multiple millions of dollars on a new plant facility,” Loesch said.
What Will the Upgrade Save?
The team at Meeker Equipment Co. Inc., Belleville, Pennsylvania, looks at investment from a cost-savings point of view also. “Our team looks at how the asphalt plant can reduce its cost per ton,” Jeff Meeker said. “This can be achieved in a number of ways. For example, is the plant burning the cheapest fuel to dry the aggregate? Can the plant increase the amount of RAP into the mix without harming quality? Are too many trucks being allocated to a job? Could trucking be minimized with additional silo storage? Are plants using automation and the Internet/smartphones to get high quality information to their employees? Finally, sometimes the next best investment is in safety. We look at products that keep workers safe and keep sites clean from spills.”
Meeker introduced the smartphone-monitoring concept to its customers with its Patriot hot oil heater. “Today, customers can see the status of their hot oil heater from their smartphones anytime and anywhere. We also introduced the Liquid Vision to the market so tank farms become safer. We monitor liquid levels in tanks and control filling into those tanks. All this is done to make filling tanks safer.”
Loesch’s Hotmix Parts & Service team looks at the facility for what he describes as items “that for a relatively small investment, yield an extremely fast payback,” and that includes monitoring. “Many customers have chosen our NiteOwl® Plant Alert to help them monitor the liquid asphalt temperature 24/7 and alert them if they’re having any falling temperature, so they don’t have a cold asphalt plant for their morning startup.”
From morning startup to most efficient loadout, the producer making the most of winter downtime may need to invest in equipment and iron, or in software and elbow grease. Travis Mick, vice president and sales manager of CWMF Corporation, Waite Park, Minnesota, discussed how the different aspects of long-term success must have the payoff of optimizing overall plant performance and turning a profit.
“The two pieces of equipment that offer the most potential for improving efficiency, minimizing costs and maximizing results are the drum and the baghouse,” Mick shared. “First, we recommend tuning the burner annually to ensure optimal operation. Second, we partner with customers in measuring and analyzing temperatures both in the drum and baghouse. With this information, we can make recommendations about flight design or rotational speed to achieve balanced temperatures. Last, we work with customers to ensure the drum and baghouse are sealed and free of leaks that can result in production losses.”
What Astec’s Sneed has seen during his years of service is a tendency for owners to produce more efficiently when times are tough. “You must be efficient enough to sustain through the lean times. When things are going great, and we’re making lots of money, we should funnel that money into upgrading efficiencies. You can improve on the things you’re doing right. If you’re not growing, you’re dying.”
Why Fix What Ain’t Broke?
One resource shared an example of an asphalt producer who has been in business for many years, successfully making mix and money. In recent years, that producer has lost a number of bids to a competitor in the marketplace because the competitor is able to control materials costs through its own asphalt terminal and the use of RAP in its mixes. Obviously, not every asphalt producer can afford to take on the debt for setting up his or her own terminal for liquid material. But isn’t it past time to invest in the equipment to successfully run RAP? Is this the right time to invest in the technology to add warm mixes to your offerings? Have you waited long enough to slope, pave and even cover the area where aggregate and RAP are stockpiled? Maybe it’s merely time to retune the burner and assess the size of the baghouse in relation to the tonnage you run for your best efficiency. Whatever time it is for you specifically, the clock is ticking on the winter down season for most producers to make decisions and make their next best plant investment.
You can contact any of the resources who shared their time and expertise for this article.
(800) 251-6042 – office
(423) 240-1754 – mobile
Clarence Richard Companies
(952) 939-6000 – office
(612) 590-0993 – mobile
Waite Park, Minnesota
(320) 267-3805 – office
(423) 821-5200 – office
(423) 488-9755 – mobile
Meeker Equipment Company Inc.
(717) 667-6000 – office
(215) 828-2651 – mobile
Reliable Asphalt Products
(866) 647-1782 – office
(216) 470-7619 – mobile
Stansteel/Hotmix Parts & Service
(502) 245-1977 – office
Tarmac International Inc.
Kansas City, Missouri
(816) 220-0700 – office
(816) 916-6806 – mobile