OP-II-3

OP-III-A-5PYROLYSIS OF HDPE IN A CONICAL SPOUTED BED REACTORElordi G., Artetxe M., Lopez G., Amutio M., Aguado R., Olazar M.University of the Basque Country,P.O. Box 644, 48080 Bilbao, Spain,gorka.elordi@ehu.esThe production and use of plastics are increasing considerably, about 4% peryear, due to their contribution to all daily activities. Thus, 5 million tonnes of highdensity polyethylene were produced in Western Europe in 2007 [1]. At present, onlya small percentage of plastic waste is recovered or recycled, less than 20%.Pyrolysis is an alternative process for converting and upgrading plastic wastes.Pyrolysis in a fluidized bed reactor and similar devices has many possibilities forlarge-scale implementation of continuous waste plastic valorization [2]. The conicalspouted bed reactor (CSBR) has interesting conditions for pyrolysis because of thelow segregation in the bed and lower attrition than the bubbling fluidized bed.Furthermore, the CSBR has great versatility in the gas residence time, which may bereduced to values near 20 ms [3].Figure 1. Schematic representation of the pirolysis unit; the CSBR in detail.Batch runs have been carried out at 550, 600 and 650 °C. The bed consists of100 g of sand (0.6 < d p < 1.2 mm), and batches of 3 g of plastic (2 mm particle size)are fed into the reactor. The nitrogen flowrate is 20 % over that required for minimumspouting velocity (23 L min –1 at room conditions). Composition of products has beendetermined by GC analysis (Agilent 6890) of the reactor outlet stream at 10 sintervals during reactions. Weight loss and gaseous stream composition have beenmonitored throughout time. The calculation of product composition at a given timehas been carried out using cyclohexane as the internal standard for mass balanceclosure, given that it is a product with insignificant yield and is easily identifiable.159