ORIGINAL PAPER Polystyrene pyrolysis using silica-alumina catalyst in fluidized bed reactor Saeedeh Imani Moqadam • Mojtaba Mirdrikvand • Behrooz Roozbehani • Abdolreza Kharaghani • Mohammad Reza Shishehsaz Received: 3 August 2014 / Accepted: 6 January 2015 Ó Springer-Verlag Berlin Heidelberg 2015 Abstract Catalytic degradation of polystyrene (PS) at ambient pressure was investigated in this study. Samples of PS and catalyst were mixed in a semi-batch reactor. Experiments were carried out in a Pyrex reactor in different conditions, taking temperature and catalyst/PS mass ratio as variables to determine the kinetic parameters. The results indicated that increasing the temperature causes conversion increase. The products of the degradation mostly consist of liquid, gas, and solid residue. The pyro- lysis of PS was examined as an effective way to recycle this polymer and recover its styrene monomer. Based on the weight loss of polymer sample, the reaction kinetic parameters are calculated and discussed in the paper. In addition, the effects of temperature and catalyst/polymer ratio were examined, comparing its result to the gaseous and liquid pyrolysis products. Since the oil product con- tained a high percentage of styrene monomer ( [ 80 %), it is possible to use it directly for the reproduction of the polymer. The experiments indicated a unique catalytic performance for degradation of PS with selectivity to aromatics more than 99 %. The products contained styrene, as the major product, and ethyl benzene, indene, and propyl benzene to some amounts in the liquid. Order of reaction, pre-exponential factor and activation energies were deter- mined using the nth order model technique method. According to the results E (activation energy) and A 0 (Pre- exponential factor) are as the following 1.1326, 194 (kJ mol -1 ) and 3.2668 9 10 14 min -1 , respectively. Keywords Catalytic conversion  Polystyrene  Pyrolysis  Polymer Introduction More than 12 % of a city solid wastes are polymer plastics including plastic food containers, toys, protective packag- ing foams, and disposable cutleries; therefore, recycling plastic wastes are an important concern for environmen- talists and scientists. The amount indicates an increase since 1960 when plastics included less than 1 % of the wastes. In 2004, about 20 million tons of plastic wastes were produced in Europe (Bazargan and McKay 2012). In 2010, 31 million tons of plastic wastes were produced; representing 12.4 % of total municipal solid waste (MSW). The United States produced approximately 14 million tons of plastics as containers and packaging in 2010, among which only 8 % was recovered for recycling (Miskolczi and Nagy 2012). The increasing amount of waste polymers (mostly Polystyrene, due to its wide application as a result of its low cost) result in enormous environmental problems and therefore waste polymer recycling is of great attention. The recycling is vital in both aspects of environmental friendly processes and energy saving. The waste polymers may be used as secondary raw materials instead of being landfilled or incinerated. The disadvantages of these two mentioned methods (landfilling and incineration) are increase in costs, environmental concerns, and the decreasing space for landfills. Although many alternatives have been proposed for destroying plastic wastes, many of them have not been used widely due to economic S. Imani Moqadam (&)  M. Mirdrikvand  A. Kharaghani Thermal Process Engineering, Otto von Guericke University, P.O. 4120, 39106 Magdeburg, Germany e-mail: saeedeh.imani@st.ovgu.de B. Roozbehani  M. R. Shishehsaz Research Center of Petroleum University of Technology, Abadan, Iran 123 Clean Techn Environ Policy DOI 10.1007/s10098-015-0899-8