Prof. Dr.-Ing. Joachim Schmidt Automotive Recycling Engineering Workshop at the Nelson Mandela Metropolitan University NMMU Port Elizabeth South Africa 2011 4 Shredder operation and post shredder Technologies
4 Shredder operation and post shredder Technologies ELV Dismantling workshop Pre-treatment Draining Dismantling Shredder Fluids Pollutants Spare parts Components Nonferrous metals After treatment of the vehicle in a dismantling workshop, the car body is taken to a shredder facility for an additional material recycling. A separation of the materials is done there. 2
Shredder operation The car that s to be shredded comes into a hammer mill and is disjointed into small pieces. Light material (non metallic materials) will be exhausted by an air seperator. The metals and heavy plastic and rubber parts reached a conveyor belt and are further processed. 3
Shredder operation Shredder plant in Germany. It is easy to recognize, how a pressed body is fed to the shredder. In the background one can see the "air separators partly. Naturally a shredder processes not only automobile bodies, but also other mixing and collecting scrap metal. These include production residues, metallic building materials and household electrical appliances such as washing machines. 4
Shredder Technology, Process chain ELV Dismantling workshop Pre-treatment Draining Dismantling Shredder Magnet separator Ferrous metals Firstly, the heavy shredder residues move through a magnetic separator. Steel and iron are separated there (ferromagnetic materials). 5
Shredder operation - operation of a magnet separator to the separation of ferrous metals Shredder material Conveyer belt Magnet Conveyer belt Ferrous metals Operation of a "magnetic separator. The ferro-magnetic parts adhere firmly to the end of the magnet and drop onto a conveyor belt. The non-magnetic material falls down directly. In the material flow are also high-alloy steels, which are not ferromagnetic. The shown device is known in the field of process technique as "conveyor magnet. Non ferrous metals and non metals 6
Shredder Technology, Process chain ELV Dismantling workshop Pre-treatment Draining Dismantling Shredder The remaining material stream is further treated depending on the installation in three ways: Hand sorting of non ferrous metal Eddy current separator for Al, Mg Float-sink-plant for Al, Mg. Magnet separator Sorting by hand Eddy current separator Swim sink plant Ferrous metals Nonferrous metals 7
Shredder operation - Operation of an eddy current separator Shredder material without ferrous metals Conveyer belt Rotating magnet Eddy current separators are used increasingly because they work without separating liquids. An induced voltage is produced in the pieces which leads to a repulsive force. The particles are flung away by the belt. Ferrous metals Non metals Conductive metals (Al, Mg, Cu,...) 8
Shredder operation - Operation of a swim-sink-plant Shredder material without ferrous metals Swim-sink-stage 1 Density 2,2 g/cm 3 Swim-sink-stage 2 Density 3,3 g/cm 3 Hand sorting Shredder residues/ remelting of lead, zinc Magnesium Rubber Aluminium Non ferrous steel Copper Brass At the density separation the impetus force is made use of into liquids. One uses for metals a mixture of ferro silicon powder and water. 9
New techniques for metal separation, automatic single piece sorting Mirror Laser Detector Signal device, comparison with known X-ray spectrum (spectrum library) Conveyor belt, isolation of metal mix Stimulation of the metal pieces by X-ray or laser light, emission of characteristic X-ray, finger print of the metal. Ejector (switch, flap, pressure nozzle), controlled by signal device Sorted metals (for example Aluminium and Magnesium alloys) 10
New techniques for metal separation, RFA, System Aumund The figure shows the sorting machine of the Aumund company. Here, the spectrum in the metal particles will be excited by means of X-rays. The detected pieces of metal are sorted with the help of a slide into the collection boxes. 11
Shredder Technology, Process chain ELV Dismantling workshop Pre-treatment Draining Dismantling Shredder Post shredder Technologies Shredder residues ASR (incl. plastic and rubber) The second partial stream, the automotive shredder residues ASR, includes all nonmetals. These materials are seperated by a big vacuum cleaner, called air separator, during shredder operation. This material can be further separated and recovered with the help of post-shredder technologies. 12
Processing of shredder residues Product for feedstock recycling or energy recovery Shredder residues Processing (Cutting, sorting) Products Polymer granulate Blast-furnace, Pyrolysis, Gasification, Power plants,... Non-ferrous metals Ferrous metals Fluff Mineral product for remelters (Shredder sand) Various plant concepts for the separation of materials have been developed in recent years. Volkswagen has developed together with SiCon a procedure, obtaining the following materials: Rest of ferrous metals Remaining non-ferrous metals Polymer granules for feedstock recycling or energy recovery Mineral product for Remelters and Fluff for the drying of sludge. 13
Post shredder technologies principle of gasification Polymer granulate Gasification medium H 2 O, O 2 Syntetic gas (CO,H 2, CH 4 ) Gasification reactor 2C + O 2 => 2 CO C + H 2 O => CO + H 2 C + CO 2 => 2CO CO + H 2 O => CO 2 + H 2 C + 2 H 2 => CH 4 CO +3H 2 => CH 4 + H 2 O During the gasification of the polymer granules the material is partially oxidized together with a gasification medium (water, oxygen). The major components of carbon monoxide, hydrogen and methane creates with the specified reaction equations a synthetic gas. After cleaning the gas, it can be used directly or stored for later use. Gas purification Temperature Purified gas for use 14
Feedstock recycling by gasification (production of synthesis gas) The following illustration shows the plant Schwarze Pumpe. It is a pure gasification plant and was used in Estern Germany for the production of fuel gas from coal. Plant Schwarze Pumpe in Germany 15
Feedstock recycling by gasification (System Thermoselect) The company Thermoselect operates a pilot plant in Switzerland. According to this model plants in Germany and Japan were built. Especially in Japan this method for the recycling of household waste is used. Plant Chiba, Japan Plant Mutsu, Japan Plant Locarno, Switzerland 16
Post shredder technologies principle of pyrolysis Polymer granulate Pyrolysis reactor Gas (CO 2, H 2 O, CH 4, H 2,..) Another possibility for recovery of the polymer granules is the pyrolysis. These hydrocarbon chains are broken under exclusion of oxygen and are modified from the solid material to a gas and a carbon residue. Condensation Pyrolysis carbon Preparation Oil Coke for blast furnace Temperature 17
Post shredder technologies principle of energy recovery Thermal reactor Exhaust Shredder residues Heat for use Ashes/Slag Separation Metals Temperature In the energy recovery, the polymer granules are converted with a supply of oxygen to carbon dioxide. The oxidation heat can be converted into electrical energy or can be used to heat buildings. 18
Thermal treatment of tyres Engineering Workshop Automobile Recycling Plant Year Capacity Gummi-Mayer 1 BRD 1973 1.000 kg/h Gummi-Mayer 2 BRD 1983 1.400 kg/h Reifen-Ihle BRD 1979 490 kg/h Modesto USA 1987 3.200 kg/h (5 Mio Tyres/a) Sterling USA 1991 5.950 kg/h (10 Mio Tyres/a) Chewton Glen USA 1996 7.510 kg/h Power plant in Modesto, California Location of power plants 19