Syngas from steam gasification of polyethylene in a conical spouted bed reactor Aitziber Erkiaga, Gartzen Lopez, Maider Amutio, Javier Bilbao, Martin Olazar ⇑ Department of Chemical Engineering, University of the Basque Country UPV/EHU, P.O. Box 644, E48080 Bilbao, Spain highlights  The spouted bed reactor performs well with carbon efficiency being above 90%.  The 850–900 °C range is suitable for a high yield of H 2 and a low yield of tar.  Steam/plastic ratio increases process efficiency, H 2 yield and favours tar cracking.  Tar yield is low (6%) and made up of monoaromatic hydrocarbons.  The syngas ratio (H 2 /CO = 2.2) is suitable for hydrocarbon or DME synthesis. graphical abstract article info Article history: Received 2 July 2012 Received in revised form 25 February 2013 Accepted 13 March 2013 Available online 27 March 2013 Keywords: Steam gasification Spouted bed Plastic waste Hydrogen abstract The steam gasification of high density polyethylene in continuous mode has been carried out in a conical spouted bed reactor. The effect of temperature (in the 800–900 °C range) and steam/plastic mass ratio (between 0 and 2) on the distribution of products (gas and tar) and their composition has been studied. In order to reduce tar formation, two catalysts have been used in situ, namely, olivine and c-Al 2 O 3 . The spouted bed reactor has an excellent performance between 850 and 900 °C, and an increase in the steam/ plastic ratio from 1 to 2 only improves slightly both carbon conversion efficiency (to 93.6% with steam/ plastic ratio = 2) and hydrogen concentration (61.6%). The use of olivine and c-Al 2 O 3 instead of sand gives way to a moderate reduction in the tar formation , whose yield is 4.8% with olivine. The syngas obtained has a H 2 /CO ratio of 2.2, with a low tar content whose composition (monoaromatics, mainly benzene) augurs well for the use of the syngas in DME synthesis. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction The world’s overall consumption of plastics in 2010 was 230 million tones and the predictions are for an upward trend of 3% annual in developed countries and 10% in developing countries. Consequently, the development of recycling processes at industrial scale is urgent to avoid the environmental problems related to waste plastic landfill and contribute to intensifying the upgrading of oil, of which 8% is used in the production of plastics [1]. Amongst waste plastic valorisation routes, thermochemical processes have best perspectives and they have been developed to pilot and dem- onstration scale [2]. Pyrolysis is an interesting option for the treat- ment of polyolefins to obtain fuels and monomers [3,4]. Gasification is another alternative, given that it is a flexible process that allows operating with a wide range of plastics, mixed plastics and even combining different wastes, such as biomass [5,6] and coal [7,8]. Furthermore, depending on the gasification agent used, it is possible to direct the process towards the production of a gas fuel with low (using air) or high (using pure oxygen) heating 0016-2361/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.fuel.2013.03.022 ⇑ Corresponding author. Tel.: +34 946 012 527; fax: +34 946 013 500. E-mail address: martin.olazar@ehu.es (M. Olazar). Fuel 109 (2013) 461–469 Contents lists available at SciVerse ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel