Shredded refuse

This paper considers plastics and their positive role during the lifetime of a car, the case of end-of-life vehicles, energy recovery from shredding refuse by means of co-... 

The Union Carbide Purox system (17) uses municipal solid waste as the feed. Shredded ferrous-free refuse enters the top of the conversion furnace and is contacted countercurrently with hot combustion gases from the reaction occurring in the hearth. 

The energy recovery system selected dictates the extent that solid waste must be prepared. Some systems require nothing more than the removal of massive noncombustibles, such as kitchen appliances from the refuse, while other processes require extensive shredding, air classification, reshredding, and drying, In conjunction with fuel preparation, it is usually worthwhile to reclaim metals and glass for recycling. 

Refuse-Derived Fuel (RDF) Fuel processed from municipal solid waste that can be in shredded, fluff or dense pellet fonns. 

Waste materials cover a diversity of products such as wood waste, used tires, waste from agricultural products such as rice husks, and municipal solid waste. Some of these waste materials are very heterogeneous while others are more uniform. Different types of waste are commonly processed using incinerators or reactors that process waste material by heat. The processed materials are commonly classified in char, liquid, and gasses. The municipal solid waste (refuse derived fuel), which is probably the most heterogeneous, is initially processed by the removal of metals, is shredded, dried, and pelletized, and only after that is it processed in heated reactors. 

Figure 7. Comparison of daily temperatures for cubed and shredded refuse during storage tests...

Leaves and vines must also be shredded for densification. Mint straw, hop vines, cotton gin trash and municipal refuse can be coarsely cut and cubed with dry materials when possible. 

Saarberg Fernwarme utilizes a rotary-grate vertical shaft gasifier operating on a mixture of oxygen and steam. The refuse is pretreated by shredding and magnetic removal of ferrous metal. 

Hammer Mills. These are very effective for size reduction of brittle materials. Hammer mills for shredding refuse are available with fixed or swing hammers, bolted on the high-speed rotating shaft (700-1,200 RPM). Major and minor variations exist in the design of each manufacturer s hammer mill. 

The pneumatic conveyors are suitable for refuse-derived fuel, dense and light plastics, granulated paper, milled glass, and chip wood/timber. They are not suitable for mixed municipal solid waste due to the variable characteristics of the components, organics/putrescibles due to odors, and material deposition in the rotary valves, and metal objects, except shredded aluminum. 

Refuse-Derived Fuel (RDF) - A solid fuel produced by shredding municipal solid waste (MSW). Noncombustible materials such as glass and metals are generally removed prior to making RDF. The residual material Is sold as-ls or compressed into pellets, bricks, or logs. RDF processing facilities are typically located near a source of MSW, while the RDF combustion facility can be located elsewhere. Existing RDF facilities process between 100 and 3,000 tons per day. 

There are two basic types of solid waste combustors currently in operation in the United States, mass burn facilities and refuse derived-fuel (RDF) facilities. Mass burn facilities manage over 90% of the solid waste that is combusted in the United States. Mass burn facilities are designed to handle unsorted sohd waste, whereas RDF facilities are designed to handle preprocessed trash. The ash produced by RDF facilities, where the incoming municipal solid waste stream is shredded and presorted to remove ferrous metal and in certain cases nonferrous metal prior to combustion, can be expected to have different physical and chemical properties from ash generated at mass burn facilities [115-118]. 

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