A mixture of post-consumer polyethylene/polypropylene/polystyrene (PE/PP/PS) with polyvinyl chloride (PVC) waste was pyrolyzed over cracking catalysts using a fluidizing reaction system operating isothermally at ambient pressure. The influences of catalyst types and reaction conditions including reaction temperatures, ratios of catalyst to plastic feed, flow rates of fluidizing gas and catalyst particle sizes were examined. Experiments carried out with various catalysts gave good yields of valuable hydrocarbons with differing selectivity in the final products dependent on reaction conditions. A model based on kinetic and mechanistic considerations associated with chemical reactions and catalyst deactivation in the acid-catalyzed degradation of plastics has been developed. The model gives a good representation of experimental results from the degradation of commingled plastic waste. The results of this study are useful for determining the effects of catalyst types and reaction conditions on both the product distribution and selectivity from hospital plastic waste, and especially for the utilization of post-use commercial FCC catalysts for producing valuable hydrocarbons in a fluidizing cracking process.
"The excessive use of these plastics is associated with generation of large quantity of wastes which is a serious threat to the environment. Several methods are used for their disposal including incineration, land filling, reuse and conversion in to value added products (Panda et al., 2010; Subramanian 2000; Vasudevan 2012; Lin et al., 2010). However, most of these methods are not cost effective (Ali et al., 2002; Rodriguez 1989; Salmiaton and Garforth 2007 ) and generate wastes with several environmental implications (Valerio 2010; Mendes et al., 2004). "
[Show abstract][Hide abstract] ABSTRACT: Pyrolysis of polypropylene (PP) and high density polyethylene (HDPE) into fuel like products was investigated over temperature range of 250 to 400 °C. The product yields as a function of temperature were studied. Total conversion as high as 98.66 % (liquid; 69.82%, gas; 28.84%, and residue; 1.34 %) was achieved at 300 °C in case of PP and 98.12 % (liquid; 80.88 %, gas; 17.24 %, and residue; 1.88 %) in case of HDPE at 350 °C. The liquid fractions were analyzed by FTIR and GC-MS. The results showed that the liquid fractions consisted of a wide range of hydrocarbons mainly distributed within the C6–C16. The liquid product obtained in case of PP is enriched in the naphtha range hydrocarbons. Similarly, the liquid product obtained in case of HDPE is also enriched in naphtha range hydrocarbons with preponderance in gasoline and diesel range hydrocarbons. The % distribution of paraffinic, olefinic, and naphthenic hydrocarbons in liquid product derived from PP is 66.55, 25.7, and 7.58 %, respectively, whereas in case HDPE, the % distribution is 59.70, 31.90, and 8.40 %, respectively. Upon comparing the hydrocarbon group type yields, PP gave high yield of paraffinic hydrocarbons while HDPE gave high yields of olefins and naphthenes. The whole liquid fractions and their corresponding distillates fractions were also analyzed for fuel properties. The results indicated that the derived liquid fractions were fuel-like meeting the fuel grade criteria.
International Journal of Green Energy 03/2014; 12(7):140303064405005. DOI:10.1080/15435075.2014.880146 · 1.22 Impact Factor
"However, the thermal degradation of plastics has a major drawback such as very broad product range and requirement of high temperature. These facts strongly limit their applicability and especially increase the cost of feedstock recycling for waste plastic treatment (Lin et al., 2010). Catalytic degradation therefore provides a means to address these problems. "
[Show abstract][Hide abstract] ABSTRACT: 2) MOL Hungarian Oil and Gas Plc. Abstract: In this work the pyrolysis of contaminated plastic waste was studied. The pyrolysis of clear and contaminated waste plastics was carried out in a tubular reactor, applying 500°C temperature. Y-zeolite catalyst was applied to reduce the contaminant level in the products and the effect of pre-treatment of raw materials was also studied. It was established that the catalyst could increase the yields of volatile products but its effect was significant only in case of clear, non-contaminated raw materials. In the absence of catalyst the pre-treating of raw materials had only moderate effect on the quantity and quality of the products. The determined properties of the low contami-nated products were advantageous with respect to their energetic utilization. However it was also cleared that the pyrolysis of high contaminated raw materials could not result in acceptable hydrocarbon fractions for refinery plants.
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