One of the best ways to get recycle wood and residue from a C&D recycling line is to grind it to fuel size and ship it to some sort of Cofired Plant or Kiln.“Fuel size” though, is different from plant to plant and State to State.
Generally, wood fired plants can handle a 6” minus product. There are some kilns that use a 3” conveyable material and many others that use a 1” blowable material to mix with their coal. The BTU values of the C&D residue are probably 5,000 to 10,000 depending on the materials being recycled in the systems.
But there is one costly constant that I see continually. There is many times some sort of high speed grinder at the end of these systems. These are probably the most costly parts of the operations.
STOP! Why does the material need to be shredded so fine. The only time you can make a case for it is if you are shipping for a 1” product, but even in these cases the infeed rates are so low there is no need for a big diameter rotor and all its expensive parts and all that wasted horsepower.
A slow speed shredder with a small screen size cannot only make the product you want, but reduce your costs by using less horsepower and limiting the wear to about 1/4 of what a high speed grinder would. The hum of that high speed rotor spinning, whether electric or $4 a gallon diesel driven, is costing you all your profit on the fuel and probably everything else too.
Screens are cheap in comparison to grinders. You really need them to remove the dirt fines from your product and reduce your ash content anyway. So if you have some oversize, scalp it off too and drop out those fines while you are at it. You’ll get more money for your fuel.
Star screens got a tarnished reputation from some of the early years in the industry, but today’s models are nothing like its predecessors. They create less dust than trommels, they don’t plug up like flat decks, you can adjust the sizing in seconds and you can create the multiple products with the same deck.
Review your operations. What if your grinding costs were reduced by over 50% and you were paid more for your fuel?
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