New Components Revive Silver Star's Asphalt Production Workhorse

A CMI 400-tph counterflow plant, which has been cranking out asphalt at Silver Star Construction Company's Moore, OK headquarter for the past 12 years, was due for an upgrade as the reliable drum mixer and some of the ductwork had reached the point of requiring a major overhaul.

For owners Steve Shawn and Craig Parker investing in new components made more sense than rebuilding the existing worn out equipment.

"We talked to some of the major plant manufacturers about what we wanted to accomplish, and Maxam Equipment came back with the solution that best addressed our needs at this time," notes Parker, vice president.

Silver Star Construction has been serving the Oklahoma City Metropolitan area for over 20 years as both a site development and road construction contractor. From earthmoving to soil stabilization to concrete or asphalt products and services, the company's 150 associates are poised to deliver the right solutions in meeting their customers' expectations.

With asphalt production and construction a significant part of the contractor's business, supported by approximately a third of its workforce, upgraded the Moore facility was a vital investment to the future success of the company.

"We knew the investment was necessary simply because some of the components were wearing out, but we also viewed it as an opportunity enhance our production capabilities with today's technological advancements," Parker notes. "We definitely wanted to improve the overall fuel efficiency of the plant simply because we often have to process material that has a high-moisture content (During this past spring, the moisture content of the asphalt producer/contractor's aggregate stockpiles was in the 4-5% range.). And, we wanted to upgrade the facility with technology that would allow us to continue expanding the use of RAP material."

Silver Star replaced its aging 400 tph CMI counterflow drum with a 400 tph Maxam SOLO counterflow drum, equipped with a natural-gas fired Hauck Star Jet Burner.

The SOLO technology lowers exhaust stack temperatures to less than 250 degree F, cutting fuel costs by 7-10% per ton. That particular performance characteristic not only appealed to Silver Star's desire to operate a more fuel-efficient production facility, but it also allowed them to reduce emissions at the plant, produce more mix at a lower cost, and increase the RAP content of mixes produced because the SOLO technology has recycle inlet that heats RAP material directly. This means that mixes produced in drum can handle up to 50% RAP without superheating the material, which often produces blue smoke because high temperatures often burn off some of the recycled liquid asphalt binder.

The 48-foot-long by 9' 6" diameter drum is equipped with the MAXAMizer Heat Recovery System, Raptor Recycle System, TrooTrac Self-Aligning Trunnion System and the AQUABlack Solutions for Warm Mix System.

The MAXAMizer Heat Recovery System's high-efficiency flighting reduces drum exhaust temperature below 200 degrees, via a small modulating heater that's dedicated to maintaining baghouse temperature by increasing the baghouse inlet temperature to the preferred minimum of 225 degrees.

The Raptor Recycle System eliminates steam, blue smoke and higher fuel costs associated with superheating virgin aggregate by introducing RAP directly into the drum.

This allows the RAP to be warmed up by the radiant heat generated by the burner flame, limiting the time of exposure to the overall heating process – in other words, removing the moisture without cooking off the reclaimed asphalt binder.

Since the RAP is being warmed up at the same time virgin aggregated is being dried, there's no need to superheat the virgin material before mixing it with the RAP material. The technology lowers fuel consumption, reduces emissions, and allows for increased RAP percentages since it heating process is conducted at a lower temperature.