The Storage Bin
The RDF storage bin is located in the coal yard between the Resource Recovery Plant and the municipal power plant. This is a two-compartment RDF receiving bin. Each compartment has a volume of 31,500 cubic feet, for a total capacity of 250 tons of RDF. The RDF is pneumatically conveyed from the Resource Recovery Plant to the bin, then discharged through a rotating distributor at the top of each compartment. Since RDF is produced at a greater rate than it is consumed, the bin provides storage for the amount of RDF processed beyond the immediate boiler fuel demand.
Transversing screw-type augers move the RDF from the bottom of each compartment to drag chain conveyors. The conveyors drag the RDF to a pair of pneumatic conveyors located in the center of the bin. The RDF is blown from the bin into a pulverized coal utility boiler.
The Ames Municipal Power Plant has two pulverized coal boilers which consume RDF as a supplemental fuel. The RDF is blown into the lower section of the boiler. Complete burning of the RDF is more difficult than coal, so bottom grates have been installed in the boilers to hold refuse in the flames until as much as possible is consumed.
The Ames Power Plant annually burns about 35,000 tons of RDF, which meets about 10% of the plant's annual fuel requirements. The Resource Recovery Plant produces enough refuse-derived fuel to help the power plant heat more than 4,600 Ames homes each year.