Finish Line

The end markets for shredded tires vary widely, which means recyclers should definitely spend time researching what end markets they want to target before deciding on a shredder or shredding system.

For instance, the specification for TDF is 2-inch-by-2-inch pieces with wire still included, according to Rusty Angel, industrial division product manager at Vecoplan LLC, a High Point, N.C.-based manufacturer of shredding and grinding equipment. Traditionally, TDF is made using one or more primary shredders, which are normally dual-shaft machines, Angel says. "Whole tires are thrown into the shredder, and a wide variety of different sized chunks come out," he explains. "Those chunks that are larger than 2 inches by 2 inches are then run through another dual-shaft shredder or conveyed back and run through the original shredder again and again until they fit the 2-inch-by-2-inch size," Angel says.

A more efficient method for producing TDF, Angel says, is using a primary shredder and a secondary shredder. "First, it’s faster. Second, it saves on energy costs. Third, it saves on maintenance costs," he says.

Other markets, Angel says, require smaller particle size and wire removal, which necessitates an additional secondary shredder that can take the pre-shredded tires and reduce the size further, as well as liberate the wire from the rubber.

"For ground rubber you need equipment capable of good, clean steel extraction," says Colyar.

Material handling is another factor recyclers should consider, adds Dave Fleming of shredder manufacturer SSI Shredding Systems Inc. of Wilsonville, Ore. "Another thing for recyclers to consider is how far they need to haul the tires to their site and how far the finished product needs to be shipped to the end user," he says. "Shredded material is much denser than stacked tires, but shreds are also a lot harder to work with than whole tires from a material handling standpoint. Ideally, the plant would have most of the material coming from within a 75-to-100-mile radius and shipping the shortest distance possible. This is especially true right now with rising fuel and freight costs."

Colyar says, "TDF and TDA require equipment capable of producing very clean cut material." He adds, "If the material is not very clean, it tends to clump together, and that creates material handling issues for the end users—with feed bins and conveyors, it’s just going to wreak havoc."

Once an end market is determined, recyclers have several other factors to consider when choosing a shredder.

Primary volume and particle size are the main considerations when choosing a shredder, however, recyclers also need to factor in the kinds of tires that make up their incoming feedstock.

Fleming suggests recyclers consider the tire "matrix." "Some processors have a high percentage of truck tires. Others have a high percentage of farm implement tires. A few will have a high percentage of heavy-equipment tires. If they purchase a primary shredder that is too small or not designed to process the kinds of tires they have, they will likely fail critical parts and have a great deal of unnecessary downtime."

Processors must also consider how many shredders to include in their systems, which depends on the end markets they are targeting, as well as end markets they might want to pursue in the future. "If a given recycler is looking only to produce a TDF type product, he may only need to consider primary shredders," says Angel. "However, if a recycler is looking to make a smaller product without any wire in it, then he will need a secondary shredder after the primary shredder." As when choosing a primary shredder, a recycler should consider throughput, feedstock makeup, as well as operating costs when choosing a secondary shredder, Angel says.

Most processors benefit from the flexibility afforded by operating multiple shredders. "If tires are only being shredded for disposal in a landfill, then using one shredder is possible," says Angel. "But even then for most tire recyclers, the shredder is their business. If that shredder is down, then their whole plant is down." Using two smaller shredders allows a recycler to run at 50 percent capacity, even if the other shredder is not operating, he adds. "If the recycler only has one large shredder, then every time they have to work on that machine, even if it’s for routine maintenance, the whole plant is down."

From the number of shredders in a system to which specific model or shaft configuration is the best fit for a desired end market, manufacturers’ representatives sometimes see processors making avoidable mistakes when choosing a shredder.

A common mistake often happens very early in the process, according to Colyar. "They don’t research their end markets, so they end up with equipment that can’t perform," he says.

Another common mistake he sees is a lack of planning when installing the shredder or shredding system. "They end up buying an old building and trying to shoehorn processing systems into an old building," he says. "The building needs to be conducive to the system first, and the system needs to fit the product that will fit the end user, not the building."

Some processors balk at the initial capital investment, which can be a costly error in the long run. "Of course, money is a very important part of any sales process, and we all want to get the best deal we can get," says Angel. "However, there needs to be balance when weighing the costs. A given shredder may cost a few more dollars up front, but if it’s down less frequently for repairs or maintenance, if it produces more output and if it lasts longer than a cheaper machine, then that machine will have a greater value in the long run."

Fleming adds underestimating operating costs and timelines for profitability to the list of common errors. "There’s more to it than just plopping down money to purchase a tire system. Consumable parts replacement intervals are frequent due to the high-strength abrasion wire found in radial tire and tire beads. If they don’t stay on top of the consumable parts, the finished product degrades, and they may lose end users as well as risk damage to processing equipment," he says.

Colyar says he tries to get his customers to think long term. "You pay the capital cost once, but you pay the operating costs every day," he says.

The author is associate editor of Recycling Today and can be reached at jgubeno@gie.net.