CHARACTERISTICS OF BY-PRODUCTS AND DIOXIN EMISSION FROM PYROLYSIS PROCESS FOR URETHANE/STYROFOAM WASTE OF ELECTRIC HOME APPLIANCES

摘要

EU directive RoHS (Restriction of Hazardous Substances) prohibits marketing of electrical home appliances containing harmful substances such as lead, cadmium, mercury, chromium (VI), Polybrominated biphenyls (PBBs), and Polybrominated diphenyl ethers (PBDE). The enactment of RoHS was a big shock to Asian companies and especially to Japanese companies as they have supplied major portion of their products to the global market. Influenced by RoHS, most countries enacted the regulations and laws related to prohibiting the use of such substances in the home appliances. The recycling rate of home appliances such as washing machine, TV, and air condition is currently above 90%, which is mostly recycled in waste treatment/recycling facilities. In case of refrigerator and washing machine all parts are recycled except urethane/styrofoam (14.36%). During recovery process, the refrigerant (CFCs) from the refrigerator is first recovered. After then copper, iron, aluminum, plastic, and rubber are separated and pass through the crushing and grinding process. The reclaimed metals are almost recycled. Urethane/Styrofoam mixture is collected from urethane separation device. The mixture ratio of urethane and styrofoam is usually 8.6:1, which are difficult to separate. So, in most of the countries, the mixture is disposed of in landfill or is directly incinerated.In this study, we evaluated the recycling possibility of urethane/styrofoam by a pyrolysis process to generate any usable products such as syngas and use of residue as sorbent-activated carbon. A series of pyrolysis and carbonization experiments for the mixture sample were carried out at various temperatures, and product gas, carbon characteristics and loss of ignition were analyzed to observe the characteristics of products and the feasibility of such technology utilization.