Catalytic and thermal depolymerization of low value post-consumer high density polyethylene plastic * Bidhya Kunwar a, * , Bryan R. Moser b , Sriraam R. Chandrasekaran a , Nandakishore Rajagopalan a , Brajendra K. Sharma a, ** a Illinois Sustainable Technology Center, Prairie Research Institute, University of Illinois, Urbana-Champaign, IL 61820, USA b United States Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Peoria, IL 61604, USA article info Article history: Received 15 July 2015 Received in revised form 25 April 2016 Accepted 5 June 2016 Keywords: TGA Pyrolysis Catalyst Gasoline Diesel Ultra-low sulfur diesel abstract The feasibility of catalytic and non-catalytic pyrolytic conversion of low value post-consumer high density polyethylene (HPDE) plastic into crude oil and subsequent distillation was explored. Translation of optimized conditions for catalytic and non-catalytic pyrolysis from TGA to a bench-scale system was validated using another kind of plastic (HDPE). The properties of the plastic crude (PC) oil and residue were studied for boiling point distribution; molecular weight distribution; elemental composition; and thermal degradation. The plastic crude oils had properties similar to conventional crude oil. The resulting PC oils were distilled into motor gasoline, diesel #1, diesel #2, and vacuum gas oil fractions. An increase in gasoline and diesel-range fractions was observed with Y-zeolite and MgCO 3 catalysts, respectively. Diesel and vacuum gas oil fractions were the major products in the absence of catalyst. The distillate fraction was characterized for fuel properties, elemental composition, boiling point, and molecular weight distribution. The fuel properties of the diesel-range distillate (diesel fraction) were comparable to those of ultra-low sulfur diesel (ULSD) fuel. Market demand, growth, and value of end products will dictate which process, non-catalytic or catalytic (Y-Zeolite/MgCO 3 ), is best suited for providing the product portfolio for a particular scenario. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Polyethylene (PE) and polypropylene (PP) are two major plastics used widely in packaging, electronics, storage, and personal care products due to their low cost, durability, and versatility [1]. Proper end-of-life management of these waste plastics is a serious prob- lem throughout the world, as only about one percent of plastics are recycled [2]. The disposal of plastics in landfills poses a major environmental concern, because they may take centuries to degrade naturally and they currently occupy a large volume of expensive landfill space [2]. In addition, leaving that carbon in landfills is not the most efficient way of carbon utilization. Thermochemical conversion is an attractive route to produce fuels from these waste plastics while diverting them from landfills [1]. The plastic fuels have fuel properties comparable to fossil fuels [3]. PE and PP are polymers containing only carbon and hydrogen. Therefore, unlike biofuels, the need for further upgrading of plastic fuels can be avoided. The plastic fuels have high calorific value and are non-acidic and non-corrosive due to the absence of water and oxygen, unlike biofuel [3e7]. Sharma et al. obtained approximately 20% motor gasoline, 41% diesel #1, 23% diesel #2, and 16% vacuum gas oil-range fractions from distillation of crude oil obtained from non-catalytic pyrolysis of HDPE at 440  C [3]. A recent study by Kaimal and Vijayabalan showed that oil synthesized from the waste plastic has similar properties to that of diesel [8]. It has also been shown that the waste plastic oil can be used in engines without any modifications [8]. One thermochemical conversion process is py- rolysis which is a thermal degradation method in which larger polymeric chains and biomass are broken into smaller hydrocar- bons in absence of air/oxygen [9e15]. A wide distribution of hy- drocarbons is obtained with changes in temperature and reaction * Disclaimer: Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. USDA is an equal opportunity provider and employer. * Corresponding author. ** Corresponding author. E-mail addresses: bkunwar@illinois.edu (B. Kunwar), bksharma@illinois.edu (B.K. Sharma). Contents lists available at ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy http://dx.doi.org/10.1016/j.energy.2016.06.024 0360-5442/© 2016 Elsevier Ltd. All rights reserved. Energy 111 (2016) 884e892 10988